5826 5830.output

* GB786234 (A)

Description: GB786234 (A) ? 1957-11-13

Improvements relating to substituted ureidocoumarin compounds and their use

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The EPO does not accept any responsibility for the accuracy of data and information originating from other authorities than the EPO; in particular, the EPO does not guarantee that they are complete, up-to-date or fit for specific purposes.

PATENT SPECIFICATION 786,234 Date of Application and filing Complete Specification: Nov 10, 1955. No 32176155. Application mode in Switzerland on Nov 12, 1954. Application made in Switzerland on Oct 3, 1955. Complete Specification Published: Nov 13, 1957. Index at acceptance:-Classes 2 ( 3), CIFI(A 3: C 5: C 6: D 3), CIF 2 (A 3: C 6: D 3), C 1 F 4 (A 3: B: C 4: C 5: C 7: D 2: D 3: F 1: F 3), C 2 84 (A 4: F: G 2: G 3: G 1 l), C 2 820, C 2 B 37 (A 2: A 3: F 3: 1: J: K: L: M), C 2 D 2; 2 ( 6), P 7 (A: C 10), P 7 D( 1 A: 2 A 1), P 7 T 2 C, P 8 (A: C 10: D 3 A: T 2 C), P 1 O(A: C 10: D 1 A: T 2 C); 15 ( 2), AIC( 2 A: 2 B: 3 A: 4), AID; and 96, B( 14 X: 22). International Classification:-CO 7 c, d CO 8 f D 061, D 21 h. COMPLETE SPECIFICATION Improvements relating to Substituted' Ureidocoumarin Compounds and their use We, J R GEIGY A -G, a body corporate organised according to the laws of Switzerland, of 215 Schwarzwaldallee, Basle, Switzerland, do hereby declare the invention, for which we pray that a patent may

be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - The invention is concerned with new 3-phenyl-7-ureido'coumarins which, because of their intensive blue to bluegreen fluorescence, are suitable as optical brightening agents for more or less colourless organic material, in particular for organic textile fibres of the most varying origin as well as for polymeric synthetic materials The invention also concerns processes for the production of the new 3-phenyl-7-ureidocoumarins It is further concerned with processes for the brightening of organic material with the new coumarin derivatives as well as, as an industrial product, ithe material brightened with the aid of these compounds. 7-Aminocoumarin compounds have already been suggested more than once as optical brightening agents for the most different types of substrata such as soap, cellulose fibres, wool, synthetic polypeptide fibres However, 7ureidocoumarin compounds which are substituted in the 3-position of the coumarin ring by a phenyl radical have not been known up to now. It has been found that new valuable 3phenyl-7-ureido-coumarins are obtained by condensing a benzaldehyde which in the 2position of the benzene ring contains a hydroxyl group or a substituent which can be converted into a hydroxyl group and in the 4position contains an acylamino group or a nitro group, with such a derivative of acetic acid which contains a phenyl, or a halogen or alkyl substituted phenyl substituent at the a-carbon atonu,:o form the corresponding 3-phenylacrylic acid derivative, and if necessary, liberating, as a hydroxyl group the substituent in the opposition to the acrylic acid radical in the e-,phenyl radical, joining this hydroxyl group together with the carboxyl function of the acrylic acid radical to form the coumarin ring and, if necessary, at any stage of the reaction saponifying the acylamino group or reducing the nitro group to the amino group in the 7-position and reacting with a carbamic acid derivative to form the ureido group. Benzaldehydes which can be used according ito the invention are, for example, the known 2-hydroxy-4-nitrobenzaldehyde and the -2hydroxy-4-acylaminobenzaldehydes obtainable therefrom by acylating reduction Particularly favourable however, are the 2-alkoxybenzaldehydes which contain a nitro, or preferably an acylamino group in the 4-position which can be converted into ithe amino group Because of disturbing side reactions, a primary amino group in the 4-position is to be avoided at all costs. Examples of acetic acid derivatives which can be condensed and which contain phenyl, halogenphenyl or alkylphenyl substituents at the carbon atom are phenyl acetic acid or the esters thereof, in

particular the alkyl esters, preferably however, the phenyl acetic acid nitrile (benzyl cyanide). The condensation to form the,B-phenylacrylic acid compound is performed by methods known per se, for example in alcohol in the presence of caustic alkalies, of alkali alcoholates or of piperidine If o-alkoxy aldehydes are used for the condensation, then the liberation of the hydroxyl group follows; it is performed advantageously with anhydrous aluminium chloride in inert organic solvents such as benzene, chlorobenzene or nitrobenzene, possibly also in the aluminium chloridesodium chloride melt, in the pyridine hydrochloride melt or also with a solution of hydrogen bromide in glacial acetic acid Often the coumarin ring is closed at the same time For this, it is not necessary that the carboxyl group of the acrylic acid radical should be in the free form; it can be in the modified form of the carboxylic acid ester, carboxylic acid amide and, preferably, of the nitrile group. If the coumarin ring has not bean closed on the dealkylation of the alkoxy group or if a P-( 2-hydroxyphenyl)-acrylic acid derivative is obtained as reaction product in the first step, then it is advantageous to close the ring with a solution of hydrogen halide in a low fatty acid. However, also other acid condensing agents can be used, for example zinc chloride or concentrated phosphoric acid. If a 4-nitro-2-hydroxy or -2-alkoxy-benzaldehyde is used as starting material, the nitro group is reduced to;the amino group in some step of the reaction sketched above. The 3-phenyl 7 ureidocoumarins have proved to be valuable optical brightening agents The ureido radical in these compounds derives from carbamic acids which may possibly be organically substituted at the nitrogen atom The ureido radical can already be present in the starting material or it can be introduced into the 3-phenyl 7 aminocoumarin only in the last step of the reaction In the latter case, a 3-phenyl-7-aminocoumarin is advantageously reacted in organic solution with isocyanates. An important modification of the process according to the present invention consists in converting the 3-phenyl-7-amino-coumarin by methods known per se with phosgene in inert organic solvents while warming, into the 3plienylcoumarinyl-7-isocyanates and reacting these with ammonia or organic primary or secondary amines. Thus, the new 3-phenyl-7-ureidocoumarins correspond to the general formula I (I) wherein R 1 represents the radical of ammonia or of an organic primary or secondary amine, R 2 represents a phenyl or halogen or alkyl So substituted phenyl group. A Mcording to their composition, the new 3phenyl 7 ureidocoumarins

have a more or less strong blue to bluegreen fluorescence. They can-be used for example for the optical brightening of wool, polyamide and polyurethane fibres, cellulose fibres, cellulose acetate, polyacrylonitrile fibres They can also be incorporated in polymeric synthetic substances such as polyvinyl chloride, polystyrol or polyethylene and these polymers can be worked up to form fluorescent plastic foils. In comparison with similar known compounds the colour of the fluorescence light is shifted in an interesting manner Thus the new 3-phenyl-7-ureidocoumarin compounds are a valuable addition to the group of fluorescent coumarin compounds. The following Examples 1 to 8 and the Table illustrate the invention without limiting it in any way The preparation of 7-amino compounds and isocyanates usable is first set out under Preparations 1 to 6 Where not otherwise stated, parts are given as parts by weight and the temperatures are in degrees Centigrade The relationship of parts by weight to parts by volume is as that of kilogrammes to litres. PREPARATION 1. 0-co a) 19 3 Parts of 2-methoxy-4-acetylamino 80 benzaldehyde (obtained by acetylating the amino-compound described in J Chem Soc. 1741 ( 1927)) and 111 7 parts of benzylcyanide are dissolved in 200 parts of 95 % alcohol and the temperature is reduced to 25-30 % A 85 solution of 7 5 parts of 50 % caustic potash solution in 40 parts of 95 % alcohol is quickly poured in while stirring The temperature rises slightly and after a few minutes a firm yellow precipitate is formed The mixture is 90 heated for 30 minutes at 40-45 to complete the reaction After cooling to 20 , the precipitated yellow coloured reaction product is filtered off, washed with alcohol and water and dried In this way 26 parts of 2-phenyl-/3 95 ( 2-methoxy-4-acetylaminophenyl)-acrylonitixile are obtained as a yellowish powder The product can be purified by recrystallisation from 10 times the amount of chlorobenzene, but this purification is not necessary for the 100 following reaction to close the ring The recrystallised preparation melts at 1950. b) 63 Parts of the -i-phenyl-13-( 2-methoxy4-acetylaminophenyl) acrylonitrile obtained are distributed while stirring in 500 parts of 105 abs benzene and 160 parts of pulverised anhydrous aluminium chloride are added The temperature rises from 20 to about 400 The yellow-brown reaction mixture is then boiled under reflux for 6 hours while stirring and, 110 after cooling, 800 parts of ice and 100 parts of 30 % hydrochloric acid are added After the benzene has been removed by steam distillation, the yellow precipitate obtained is filtered off under suction and washed with 115 water The substance obtained is not uniform and contains, apart from some 3-phenyl-7aminocoumarin, the

acetylation product thereof and in addition a non-cyclised product. from the analysis values -and chemical proper 120 ties of which it can be deduced that lit is an acetylamino hydroxy-carboxylic acid amide momm 786,234 786,234 3 of the formula: CH 3-CO-Nfi-::Cil C-C O Hi CONH;, This yellow mixture of substances is then boiled under reflux in a mixture of 700 parts of 851 % acetic acid and 118 parts of 36 % hydrochloric acid while stirring The yellow body is converted into grey ito grey-beige tiny crystals, the hydrochloride of 3-phenyl-7aminocoumarin After cooling, this hydro0 chloride is filtered off and washed once with cold 80 % acetic acid To produce the free base, the hydrochloride is suspended in 1000 parts of water whereupon complete hydrolysis into the free base and hydrochloric acid occurs The yellow coloured 3-phenyl-7aminocoumarin so obtained is filtered off, washed until the reaction is neutral and, after drying, it is recrystallized from alcohol or chlorobenzene In this way, 42-45 parts i e. 83-89 i% of the theoretical amount, of pure 3-phenyl 7 aminocoumarin are obtained. M.P 208-209 The amine can easily be acetylated by reacting with aceticanhydride in pyridine The acetyl compound forms colourless needles which melt at 264-265 uncorrected. PREPARATION 2. C Hi CO Nfl R c H =,Co Q-CO 6 Parts of a-phenyl-/-( 2-methoxy-4-acetylaminophenyl)-acrylonitrile obtained according to Preparation la, are heated for 30 minutes with 30 pants of pyridine hydrochloride at 180-200 and then the melt obtained is poured into 150 parts of water The yellowbrown body which precipitates is filtered off, washed with water, dissolved hot in 40 parts of pyridine, filtered and 10 parts of acetic anhydride are added On cooling, brownish coloured crystals precipitate which are drawn off under suction and purified by recrystallisation from ethylene glycol monomethyl ether. 3-Phenyl-7-acetylaminocoumarin is obtained in this way as almost colourless needles which melt at 2650 The acetyl derivative can be converted into the 3-phenyl-7-aminocoumarin described in Preparation 1 by boiling with concentrated hydrochloric acid. PREPARATION 3. o-co 4 Parts of c 4-phenyl-/-( 2-methoxy-4-acetylaminophenyl)-acrylonitrile obtained according to Preparation la, are added ito a melt of 32 parts of aluminium chloride and 8 parts ol sodium chloride at 120-130 and the whok is stirred at the same temperature for 5 minutes Ice and 301 % hydrochloric acid are then added to the yellow melt, the yellow body which precipitates is filtered off, washed and finally boiled with acetic acid +

hydrochloric acid in a manner analogous to that described in Preparation lb) Working up analogous to Preparation lb) produces the same 3-phenyl-7-aminocoumarin -which melts at 208 . PREPARATION 4. O-Co 15.2 Parts of p-chlorobenzylcyanide and 19.3 parts of 4-acetylamino-2-methoxybenzaldehyde in 20 parts of 95;% alcohol are condensed in a manner analgous to that described 70 in Preparation la) with 7 5 parts of 50 % caustic potash solution The a -(p-chlorophenyl)-3-( 2 methoxy-4-acetylaminophenyl)acrylonitrile obtained crystallises from chlorobenzene in fine yellow clusters of needles, 75 which melt at 2500 uncorrected In order to convert the acrylonitrile derivative obtained into 3-(p-chlorophenyl) 7 -aminocoumarin, it is added at 110-115 ' to a melt of 200 parts of anhydrous aluminium chloride, 40 parts of 80 sodium chloride and 10 parts of potassium chloride while stirring and stirring is continued for 30 minutes at 105-110 until a homogenous brown melt is obtained The melt is then poured while stirring into a mixture 85 of 1000 parts of ice and 100 parts of 30 % hydrochloric acid and the whole is heated for 1 hour at 80-90 while stirring The yellow suspension obtained is cooled to 200, the yellow precipitate is filtered off, washed with 90 water and then stirred for 3 hours at 1000 in a mixture of 300 parts of 80 % acetic acid and 50 parts of 30 % hydrochloric acid The pale yellow precipitate obtained is filtered after being cooled, washed with 80,% acetic 95 acid, stirred in 300 parts of water, again filtered and washed until the reaction is neutral After drying, 21 parts of the crude 3-(p-chlorophenyl)-7-aminocoumarin are obtained as a greenish-yellow powder The new 100 compound crystallises from chlorobenzene in small yellow crystals which melt at 2520 uncorrected. The same product is obtained if in this Preparation the 19 3 pants of 2-methoxy-4 105 acetylaminobenzaldehyde are replaced by 20 7 parts of 2-ethoxy-4-acetylaminobenzaldehyde (M.P 136). PREPARATION 5 O-co 13.1 Parts of p-methylbenzyl cyanide are reacted in a manner analogous to that des786,234 4 786,234 cribed in Preparation 4 with 19 3 parts of 2methoxy-4-acetylaminobenzaldehyde to form -(p-methylphenyil)-i-( 2-methoxy 4 acetylaminophenyl) acrylonitrile (yellow platelets from chlorobenzene, M P 2220) and then further condensed to form the coumarin compound. 3-(p Methylphenyl) 7 aminocoumarin obtained (M P 220 ) has similar properties to the product produced according to example 1. PREPARATION 6. Oo C=N 9-C Heo CO( co 23.7 Parts of 3-phenyl-7-aminocoumarin are dissolved in 1000 parts of abs 'chlorobenzene at 1100 and converted into the hydrochloride by the introduction of abs hydrogen chloride The almost colourless suspension of the base hydrochloride so obtained

is then cooled ito 500 and is reacted at a rising temperature while stirring with excess phosgene. As soon as the temperature has reached 100 -110 ', phosgene is still introduced until the HC 1 formation is complete The temperature is then raised to 1300, upon which an almost complete solution is obtained After hot filtration from the chlorobenzene solution, the resulting 3-phenylcoumarinyl ( 7)-isocyanate crystallises out in colourless glittering little flakes After cooling completely, the crystals are drawn off under suction, washed with some benzene and dried for a short time The yield is 22-24 parts, i e 83-92 % of the theoretical The new isocyanate melts at 2330 uncorrected. Because of its -N= C=O group which can be easily hydrolysed the isocyanate itself is not really suitable as a brightening agent but it is a very valuable intermediate product for the production of numerous ureas and urethanes which are suitable as brightening agents. If in this Preparation the 23 7 parts of 3phenyl-7-aminocoumarin are replaced by 25 1 parts of 3-(p-methylphenyl)-7-aminocoumarin or by 27 15 parts of 3-(p-chlorophenyl)-7aminocoumarin, then the 3-(p-methylphenyl)coumarinyl-( 7)-i'socyanate (M P 2140) or the 3-(p-chlorophenyl) coumarinyl-( 7)-isocyanate (M.P 225 ) respectively are obtained These isocyanates are also valuable intermediate products for the production of optical brightening agents. EXAMPLE 1. 26 3 Parts of the 3-phenyl coumarinyl-( 7)isocyanate obtained according to Preparation 6 are dissolved at 120-125 in 300 parts of nitrobenzene and 6 5 parts of monoethanolamine are added all at once The temperature rises spontaneously to 132-136 and the solution still remains clear It is allowed to cool At even 125-130 the reaction product begins to precipitate in pale yellowish fine crystals and on cooling completely to 10-20 the reaction mixture consists of a thick crystal broth After filtering under suction, the N( 13-hydroxyethyl) N'-l 3-phenyl coumarinyl( 7)l-urea is washed with some nitrobenzene and benzene and dried at 70-80 in vacuo. The urea which is obtained as a pale yellowish powder in a yield of 29-31 parts ( 90-96 %' of the theoretical), melts on decomposition at 216-218 In alcoholic solution it has a very vivid blue fluorescence in daylight The product, can be recrystallised from hot alcohol upon which the melting point increases by 1-2 Due to its strong fluorescence and its good drawing power on to various substrata, such as, e g wool, acetate silk and Nylon, the new urea derivative can be used as an optical bleaching agent Contrasted with the 7-alkyl amino-coumarins used in practice as brightening agents, this coumarin derivative has the advantage of a better fastness to light and a more blue white shading If in this example the 26 3 parts of

3-phenyl-coumarinyl-( 7)isocyanate are replaced by 27 7 parts of 3(p-methyl phenyl) coumarinyl-( 7)-isocyanate or by 29 8 parts of 3-(p-chlorophenyl) coumarinyl-( 7)-isocyanate then the N-(f 3-hydroxy-ethyl) N' l 3 (p-methyl phenyl)-coumarinyl-( 7)J-urea (M P 2550 on decomposition) or the N-ffl-hydroxyethyl) NI l 3-(pchlorophenyl) coumarinyl-( 7)l urea (M P. 2250 on decomposition) respectively are obtained These two ureas have a somewhat more green fluorescence and can also be used as optical bleaching agents Due to its good substantivity, also on cellulose fibres, N-(flhydroxyethyl) N'-l 3-(p-methyl phenyi)-cou 1 marinyl-( 7)-urea has a strong brightening effect. EXAMPLE 2. \G-CO 26.3 Parts of 3-phenyl-coumarinyl-( 7)-iso 105 cyanate obtained according to Preparation 6 are dissolved hot in 1000 parts of chlorobenzene and a solution of 3 1 parts of methylamine dissolved in chlorobenzene is added. The N-methyl-N'-l 3 phenyl coumarinyl 110 ( 7)1-urea separates immediately as a yellowish crystalline precipitate After cooling, the product is drawn off under suction, washed with a little chlorobenzene and dried The yellowish crystals which are obtained in an almost 115 quantitative yield, melt at 3200 uncorrected and they dissolve in hot alcohol with a brilliant blue fluorescence This urea derivative is also 786,234. decomposition) is obtained which has a some 50 what more greenish fluorescence This urea derivative can also be used for the brightening of substrata. Ex AMPLE 5. Parts of previously bleached wool fabric, 55 e.g wool flannel which has a slightly yellowish appearance, are treated in a dyebath (liquor ratio 1: 30) which contains 0 05 parts of the compound obtained according to example 1 and 2 5 parts of Glaubers salt The 60 treatment is for 30 minutes at 50-60 The goods are then rinsed and dried The wool so treated has a higher white content than untreated wool. A similar effect is obtained if the compound 65 according to example 3 is used instead of that according to example 1. EXAMPLE 6. Parts of slightly yellowish Nylon material are treated for 30 minutes at 60-70 70 in a dyebath (liquor ratio 1: 40) which contains 0 005 parts of the brightening agent obtained according to example 1 The goods are rinsed with cold water and dried in the air The material so treated has a much more 75 white appearance than untreated material. A very similar action is obtained if instead of the brightening agent according to example 1, one according to example 2 is used. EXAMPLE 7 80

Parts of white woollen knitted goods are washed for 30 minutes at 40-50 in 1,000 parts of a washing liquor which contains 2 5 parts of the sodium salt of the acid dodecyl sulphate, 2 5 parts of Glaubers salt 85 and 0 05 pants of the brightening agent obtained according to Example 1 The goods are then rinsed and dried in the air Woollen goods so washed have a considerably more white appearance than when washed without 90 the addition of the brightening agent mentioned. EXAMPLE 8. Parts of polyacrylonitrile fabric which appears slightly yellowish are treated for 30 95 minutes at 95-100 in a dyebath (liquor ratio 1: 50) which contains 0 01 parts of the brightening agent obtained according to example 3 as well as 0 4 parts of 80 % acetic acid After rinsing and drying, the polyacrylo 100 nitrile material so treated has a considerably more white appearance than the untreated material. The compounds listed in the following Table are obtained by analogous processes 105 They are suitable for the optical brightening of the substrata indicated. a valuable brightening agent for diverse substrata. If in this example the 3 1 parts of methylamine are replaced by 4 5 parts of ethylamine or 4 5 parts of dimethylamine or 5 9 parts of propylamine, then N-ethyl N 1 l 3-phenylcoumarinyl-( 7)l-urea (M P 3150); N Ndimethyl NI l 3 phenyl-coumarinyl-( 7)lurea (M P 2470); N-propyl-N 1-l 3-phenylcoumarinyl-( 7)l -urea (M P 2330) are obtained in an analogous manner. Due to their strong fluorescence and good drawing power, all three products are suitable for the optical bleaching of various substrata. EXAMPLE 3. / N CHC 1-N CQ ac C% 0-co 8.8 Parts of N N-dimetiiyl-ethylene diamine are reacted with 26 3 Parts of 3-phenylcoumarinyl-( 7)-isocyanate dissolved in chlorobenzene The N-( 13-dimethylaminoethyl)-NIl 3-phenyl-coumarinyl ( 7)l urea obtained which melts at 2060 dissolves in diluted acetic acid with a blue fluorescence and is suitable for the brightening of various substrata such as, e g Nylon, polyacrylonitrile fibres, acetate silk and wool If 10 2 parts of 7 y-dimethylamino-propylamine are used instead of the assymmetrical dimethylethylene diamine, then N-(y-dimethylaminopropyl) N 1-l 3 phenylcoumarinyl-( 7)l-urea (M P 1930) is obtained which is somewhat less active as a brightening agent. EXAMPLE 4. 0-co 4.74 Parts of 3-phenyl-7-aminocoumarin are dissolved at 60-70 in 150 parts of glacial acetic acid and a concentrated aqueous solution of 5 parts of potassium cyanate is added On cooling, the 3-phenyl-coumarinyl( 7)-urea precipitates in pale yellowish fine crystals The urea derivative melts on decomposition at 3300 and, in

ethylene glycol monoethyl ether, it fluoresces a strong blue This product also is excellently suitable for the optical bleaching of acetate silk and Nylon If the 4 74 parts of 3-phenyl-7-aminocoumarin are replaced by 5 02 parts of 3-(p-methyl phenyl)-coumarinyl-( 7)-urea (M P 3150 on 786,234 786,234 No. Compound 1 Nky-iethoxypropyl-N 1-3-phenylcoumarinyl-( 7)-urea (M P 2050) 2 N-a-methyl-,B-hydroxyethyl-N'-3phenylcoumarinyl-( 7)-urea (M P. 1930) 3 N-hydroxyethyl-N-methyl N-3phenylcoumarinyl-( 7)-urea (M P. 1980) 4 N-carboxymethyl-N' 3 phenylcoumarinyl ( 7)-urea (M P 240 on decomposition) 5 N-,8-sulphoethyl-N' 3 phenylcoumarinyl-( 7)-urea. 6 N-3-sulphophenyl N 1 3-phenylcoumarinyl-( 7)-urea. 7 N-4-methyl 3 -sulphophenyl-N'3-phenylcoumarinyl-( 7)-urea. Produced according to example Ex 1 + y-methoxypropylamine Ex 1 + ac-methyl-,3hydroxyethylamine Ex 1 + hydroxyethylmethylamine Ex 1 + aminoacetic acid. Ex 1 + Taurine Ex 1 + 3-aminobenzene sulphonic acid Ex 1 + 2-methyl-5aminobenzene 1 sulphonic acid. Suitable for the brightening of polyamide fibres cellulose acetate fibres polyamide fibres cellulose acectate fibres, wool polyamide fibres cellulose acetate fibres polyamide fibres polyamide fibres cotton viscose, paper cotton, viscose, paper

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* GB786235 (A)

Description: GB786235 (A) ? 1957-11-13

Process for the germicidal treatment of liquids

Description of GB786235 (A) Translate this text into Tooltip



COMPLETE SPECIFICATION Process for the germicidal treatment of liquids I, HoRsT-GUENThER ROTT, a German National, the sole personally responsible partner in the firm Schoeller & Co. Elektrotechnische Fabrik, of 115-119, Moerfelder Landstrasse, Frankfurt am Main-Sued, Germany, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention concerns the germicidal treatment of liquids. Germicidal treatment of liquids with ultrasonic waves, has already been proposed. Thus it is known, for example, to utilise an ultrasonic pipe or whistle effect to treat a liquid which is allowed to flow at high speed against an edge, whereby ultrasonic oscillations arise in the liquid, which is consequently de-germinated. The effect of the sound at the high flow velocity of the liquid, however, is of such a short duration that neither a sound dispersion sufficient for degermination nor of uniform sound distribution in all the parts of the liquid can reliably be achieved. This process is therefore not wholly effective in practice. According to another known process, the liquid is set in motion by means of a centrifuge, whereby on impingement of the liquid on a fixed wall, ultrasonic oscillations likewise can arise. In this case also, however, there is no guarantee that the sound distribution has a sufficient germicidal action. Above all, moreover, separation of the degerminated portions of the liquid from those not de-germinated is not possible in the two processes described. It is an object of the invention to provide a process for the germicidal treatment of liquids with ultrasonic waves by means of which those portions of the liquid which are to be exposed to intensive sound radiation are completely separated from the remainder of the liquid. Exact and continuous control of the degree of sound intensity having a sufficient germicidal action is thus possible. The invention makes use of the known phenomenon that liquids which are

exposed to a strong ultrasonic effect are converted far below their boiling point into mist, which escapes from the liquid. According to the present invention, therefore, the liquid is atomised ultrasonically, the resulting mist is conducted away and is then condensed. Only that part of the liquid is atomised which is exposed to a maximum sound intensity. With a sufficient value of sound intensity only fragments of bacteria pass into the mist, but no living bacteria. The minimum value of the intensity for atomisation of the liquid in the ultrasonic field to begin is dependent upon the specific gravity of the liquid, its viscosity and its vapour pressure. The said minimum value for atomisation can thus be increased by producing an excess pressure above the surface of the liquid. The process proposed by the invention is of especial importance in the germicidal treatment of liquids for therapeutic purposes. What I claim is : - 1. A process for the germicidal treatment of liquids characterised in that a liquid is atomised ultrasonically, and that the resulting mist is conducted away and is then condensed. 2. A process as claimed in claim 1, in which the pressure above the surface of the liquid is above atmospheric pressure.

* GB786236 (A)

Description: GB786236 (A) ? 1957-11-13

Electric wave-signal modifying apparatus

Description of GB786236 (A)

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US2890273 (A) US2890273 (A) less Translate this text into Tooltip



PATENT SPECIFICATION 786,236 Date of Application and filing Complete Specification: Dec 5, 1955. No 34806/55. Application made in United States of America on Dec 14, 1954. Complete Specification Published: Nov 13, 1957. Index at Acceptance:-Casses 40 ( 3), F 3 B; and 40 ( 5), L 14 E, L 15 G( 3: 5). International C Lssification:-H 1 OH 3 c H 04 j, w. COMPLETE SPECIFICATION Electric wave-signal modifying apparatus We, HAZEL Ti NE CORPORATION, a corporation organized and existing under the laws of the State of Delaware, United States of America, of 59-25 Little Neck Parkway, Little Neck 62, New York, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - General. The present invention is directed to electric wave-signal modifying apparatus for converting a wave signal which is double side-band modulated at one phase by one component and at least partially single sideband modulated at another phase by another component into a wave signal which is double side-band modulated by both components More specifically, the present invention is directed to modifying an NTSC type of color subcarrier wave signal modulated by a double side-band Q component and a partially single side-band I component into a -subcarrier wave signal double side-band modulated by both the I and Q components. In the form of color-television system now standard in the United States, hereinafter referred to as the NTSC color-television system, information representative of a scene in color being televised is utilized to develop at the transmitter two substantially simultaneous signals, one of which is primarily representative of the luminance and the other representative of the chrominance of the image To develop the latter signals, the scene being televised is viewed by one or more television cameras which develop, for example, color signals G, R, and B individually representative, respectively, of the primary colors green, red, and blue of the scene The signals G, R, and B are combined

in specific proportions to develop a signal Y representative of the luminance of fpr Jv -' the televised image Additionally, in one form of NTSC color-television system, the signals R and B are modified to color-difference signals R-Y and B-Y and these colordifference signals are utilized individually to 50 modulate quadrature phases of a subcarrier wave signal having a mean frequency within the video-frequency pass band The modulated subcarrier wave signal represents chrominance, that is, it represents the saturation 55 and hue of the televised image At a receiver in the NTSC system, the luminance and chrominance signals are detected and the hue and color saturation information is derived from the chrominance signal and 60 combined with the luminance signal to develop the three color signals G, R, and B which are utilized to reproduce the televised color image. Preferably, both of the color-difference 65 signals should be translated as double sideband modulation of the subcarrier wave signal However, double side-band transmission undesirably limits the band widths of the color-difference signals For example, 70 for a subcarrier wave signal of approximately 3 6 megacycles translated through video-frequency channels having pass bands of approximately 0-4 2 megacycles, the band widths of the modulating color-difference 75 signals would be limited to approximately 0.6 megacycle if these signals are to be transmitted, as double side-band modulation of the subcarrier wave signal The band widths of the color-difference signals that are 80 utilized cannot be arbitrarily limited since they have to be sufficiently wide to provide adequate chrominance information in the reproduced image and are, therefore, at least to some degree determined by the sensitivity 85 of the human eye to saturation changes in colors represented by the different ones of the color-difference signals Experience has indicated that the eye is less sensitive to saturation changes in colors along a green 90 white-magenta axis of a conventional colordiagram Information of approximately 0-.5 megacycle with respect to colors along such color axis appears to satisfy the response of the human eye to such colors Consequently, in an NTSC type of system a signal representative of colors along such axis and designated the Q signal is transmitted with a band width of approximately 0 5 megacycle so as to effect double side-band modulation of the subcarrier signal Having selected such Q signal, in order to provide chrominance information for the gamut of primary colors, a signal I representative of changes along another color axis orangewhite-cyan is also developed at the transmitter and utilized to modulate another phase of the subcarrier wave signal However, since the eye is more sensitive to changes along the latter color axis, the I signal requires a band width of approximately 1 5 megacycles Consequently, the I signal is transmitted partially as

double side-band modulation and partially as single side-band modulation of the subcarrier signal Nevertheless, by transmitting the Q signal only as double side-band modulation of the subcarrier signal and only the I signal as partially single side-band modulation of such wave signal the tendency for cross talk between derived I and Q signals is minimized. Though benefits are derived by utilizing I and Q modulation signals and deriving such at the receiver, due to the primary colors conventionally employed in the picture tube at the receiver, the derived I and Q signals may not be directly applied to this tube. At present, the I and Q signals are matrixed to develop the G, R, and B color signals. The requirement for such additional matrixing at the receiver to obtain the benefits of transmitting I and Q signals is undesirable at least for economic reasons It would be preferable to derive the red, green, and blue color-difference signals directly while still obtaining the benefits of the narrow band Q and wideband I signals The present invention is directed to subcarrier wave-signal modifying apparatus for modifying the received subcarrier wave signals to permit direct derivation of the green, red, blue, or any other color components. It is, therefore, an object of the present invention to provide a new and improved electric wave-signal modifying apparatus for use in the color-signal deriving apparatus of a television receiver. It is also an object of the invention to provide an electric wave-signal modifying apparatus for modifying the modulation components of a color subcarrier wave signal. It is a further object of the invention to provide an electric wave-signal modifying apparatus for use in a color-signal deriving apparatus of a color-television receiver which is effective to simplify such apparatus and minimize the number of circuit elements required therein. In accordance with the present invention, 70 there is provided an electric wave-signal modifying apparatus comprising a circuit for supplying a wave signal double sideband modulated at one phase by one component and at least partially single side-band 75 modulated at another phase by another component Such apparatus includes circuit means coupled to the supply circuit for translating the supplied wave signal with a band width including at least the double side 80 band portion of the said one component. In addition, such apparatus includes signalmodifying circuit means coupled to this signal-translating circuit means and the aforesaid supply circuit and responsive to 85 the single side-band portion of the wave signal and substantially unresponsive to the double side-band

portion of the wave signal for developing the complementary side band of the single side-band portion of the wave 90 signal and for modifying the wave signal into a resultant wave signal double side-band modulated by the one and other components. For a better understanding of the present invention, together with other and further 95 objects thereof, reference is had to the following description taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims 100 Referring to the drawings: Fig 1 is a circuit diagram of a color-television receiver having an electric wave-signal modifying apparatus in accordance with the present invention, 105 Fig 2 is a group of spectrum diagrams useful in explaining the operation of the modifying apparatus of Fig 1; Pig 3 is a circuit diagram of a modified form of a portion of the modifying appara 110 tus of Fig 1; Fig 4 is a circuit diagram of an additional modified form of a portion of the modifying apparatus of Fig 1; Fig 5 is a spectrum diagram useful in 115 explaining the operation of the modifying apparatus of Fig 4; and Figs 6 a-6 d, inclusive, and 7 a-7 d, inclusive, are spectrum and vector diagrams also useful in explaining the operation of the 120 modifying apparatus of Fig 4. General Description of Receiver of Fig 1. Referring now to Fig 1 of the drawings, there is represented a color-television receiver of a type suitable for utilizing the 125 standard NTSC color-television signal The receiver includes a video-frequency signal source 10 having an input circuit coupled to an antenna system 11 It will be understood that the unit 10 may include a con 130 786,236 786,236 3 ventional source of a video-frequency signal of the-NTSC type, for example, may comprise the initial stages of a color-television receiver including one or more stages of radio-frequency signal amplification, an oscillator-modulator, one or more stages of intermediate-frequency amplification, and a detector for deriving the video-frequency signal Such detector stage may also include 3 ( O an automatic-gain-control circuit Coupled to one output circuit of the video-frequency signal source, in cascade in the order named, is a wave-signal modifying apparatus 15, in accordance with the present invention and to be considered more fully hereinafter, a synchronous detection apparatus 16, a matrix apparatus 17, and an image-reproducing device 14 Different input circuits of the apparatus 16 are individually coupled through a phase-modifying circuit 19 and directly to an output circuit of a referencesignal generator 18 in the apparatus 15. Coupled between another output circuit of the source 10 and the cathode circuit of the :25 device 14, in cascade in the order named, are a delay line 12 and a luminance-signal amplifier 13 The delay line

12 may be of conventional construction for equating the signal delay through the units 12 and 13 to that through the units 15, 16, and 17 The luminance-signal amplifier 13 is a conventional wide band amplifier for translating signals having a maximum band width of approximately 0-4 2 megacycles The band width of the amplifier 13 may be limited to an upper frequency less than 4 2 megacycles if it is desired that no signal components having the frequency of the subcarrier wave signal be translated therethrough The image-reproducing device 14 is conventional and may, for example, comprise a single cathode-ray tube having a plurality of cathodes and a plurality of control electrodes, different pairs of the cathode and controlelectrode circuits being individually responsive to different color signals, as will be explained more fully hereinafter, and including an arrangement for directing the beams emitted from the cathodes individually onto different phosphors for developing different primary colors such as red, green, and blue. Such a tube is more fully described in an article entitled " General Description of Receivers for the Dot-Sequential Color Television System which Employ DirectView Tri-Color Kinescopes" in the RCA Review for June, 1950 at pages 228-232, inclusive It should be understood that other suitable types of color-television imagereproducing devices may be employed The synchronous detection apparatus 16 may also be of a conventional type widely used in NTSC type receivers for deriving, for example, the R-Y and B-Y color-difference signals The matrix apparatus 17 may also be conventional for combining the derived R-Y and B-Y color-difference signals into a G-Y color-difference signal. Another output circuit of source 10 is coupled through a synchronizing-signal 70 separator 20 to a line-scanning generator 21 and a field-scanning generator 22, output circuits of the latter units being coupled, respectively, to line-deflection and fielddeflection windings of the image-reproduc 75 ing device 14 An output circuit of the linescanning generator 21, for example, a terminal on the conventional horizontal output transformer therein is coupled to an automatic-phase-control (APC) system 23 in the 80 apparatus 15 for purposes to be considered more fully hereinafter A sound-signal reproducing apparatus 24 is also coupled to the video-frequency signal source 10 and may include stages of intermediate-frequency 85 amplification, a sound-signal detector, stages of audio-frequency amplification, and a sound-reproducing device. It will be understood that the various units and circuit elements thus far described, 90 with the exception of the wave-signal modifying apparatus 15, may be of any conventional construction and design, the details of such units and circuit elements being well known in the art

and requiring no further 95 description. General Operation of Receiver of Fig 1. Considering briefly now the operation of the receiver of Fig I as a whole, an NTSC type of television wave signal is intercepted 100 by the antenna system 11, selected, amplified, converted to an intermediate-frequency signal, and the latter signal further amplified in the unit 10, the video-frequency modulation components thereof being derived and 105 developed in an output circuit of the unit 10. These video-frequency modulation components comprise synchronizing components, the aforementioned modulated subcarrier wave signal or chrominance signal including a 110 color burst synchronizing signal, and a luminance or brightness signal The luminance or brightness signal is translated through the delay line 12, amplified in the unit 13, and applied to the cathodes of the image-repro 115 ducing device 14 The modulated subcarrier wave signal or chrominance signal is translated through the apparatus 15, wherein it is modified in a manner to be considered more fully hereinafter, and 120 applied to an input circuit of the synchronous detection apparatus 16 The apparatus 16 includes at least a pair of synchronous detectors individually responsive to different ones of the reference signals either translated 125 directly from the generator 18 or through the phase-modifying circuit 19 for deriving from the applied chrominance signal modulation components, for example, the R-Y and B-Y modulation components thereof 130 786,236 The derived R-Y and B-Y modulation components are matrixed in the apparatus 17 in a conventional manner to develop the color-difference signal G-Y The three color-difference signals are individually applied to different ones of the control electrodes in the image-reproducing device 14. The line-frequency and field-frequency synchronizing signals are separated from the video-frequency components and from each other in the synchronizing-signal separator The separated signals are applied to the generators 21 and 22 to synchronize the operation thereof with the operation of corresponding units at the transmitter. These generators supply signals of sawtooth wave form which are properly synchronized with respect to the transmitted signal and are individually applied to the line-deflection and field-deflection windings of the image-reproducing device 14 to effect a rectilinear scanning of the screen in such device The color-difference signals B-Y, G-Y, and R-Y combine with the luminance signal -Y in the electron guns of the device 14 effectively to develop color signals B, G, and R which intensity-modulate the cathode-ray beams emitted from the different guns Such intensity modulation of these beams together with the raster scanning results in an excitation of the different color phosphors on the image screen to effect reproduction of the televised

color image. The sound-signal modulated wave signal accompanying the television signal is selected, amplified in the source 10, and applied to the sound-signal reproducing apparatus 24 as an intermediate-frequency signal It is further amplified in the apparatus 24, detected, and utilized to reproduce sound in a conventional manner. Description of Wave-Signal Modifying Apparatus of Fig 1. Considering now the wave-signal modifying apparatus 15 of Fig 1, such apparatus includes a circuit for supplying a wave signal double side-band modulated at one phase by one component and at least partially single side-band modulated at another phase by another component Such supply circuit is the chrominance-signal amplifier 26 preferably having a pass band of approximately 2 1-4 2 megacycles An output circuit of the amplifier 26 is coupled through the automatic-phase-control system 23 to the generator 18 for controlling the phase of the signal developed therein. The apparatus 15 also includes one channel coupled to the amplifier 26 for translating the wave signal supplied by the unit 26 with a band width including at least the double side-band portion of the aforementioned one modulation component More specifically, the one channel includes, in cascade in the order named, a filter network 27 having a pass band of 3 1-4 1 megacycles and a buffer amplifier 28 coupled between the output circuit of the amplifier 26 and an adder circuit 29 The network 27, the amplifier 28, and the adder circuit 29 may be 70 of conventional construction and may be designed to have a total signal delay time equal to that for a modifying circuit now to be considered. The modifying apparatus 15 also includes 75 a signal-modifying circuit coupled to the signal-translating channel just described and to the output circuit of the amplifier 26. More specifically, the signal-modifying circuit includes, in the order named, a filter 80 network 30 having a pass band of 2 1-3 1 megacycles, a synchronous demodulator 31, a filter network 32 having a pass band of 0.5-1 5 megacycles, and a balanced modulator 33 coupled between the output circuit 85 of the amplifier 26 and another input circuit of the adder circuit 29 The synchronous demodulator 31 is a periodically conductive device responsive to the single side-band portion of the wave signal translated 90 through the network 30 and substantially unresponsive to the double side-band portion of the wave signal blocked by the network 30 The synchronous demodulator 31 may be a conventional device for deriv 95 ing a portion of the modulation component at a predetermined phase, specifically at the phase of modulation of the I signal, of the subcarrier wave signal translated

through the network 30 The balanced modulator 33 100 may be a conventional modulator for effecting modulation of a wave signal applied thereto by means of the low-frequency signal translated through the network 32. Finally, the wave-signal modifying appara 105 tus comprises means for controlling the conductivity of the periodically conductive device in synchronism with one of the modulation phases for causing the signalmodifying circuit to develop the comple 110 mentary side band of the aforementioned single side band and to modify the wave signal developed in the output circuit of the chrominance-signal amplifier 26 into a lresultant wave signal double side-band 115 modulated by both modulation components of the wave signal More specifically, such control means comprises the reference-signal generator 18 having an output circuit coupled through a phase-modifying circuit 120 34 to an input circuit of the demodulator 31 and through the unit 34 and an additional phase-modifying circuit 39 to an input circuit of the balanced modulator 33 The phase and frequency of the signal developed 125 by the generator 18 are controlled by the APC system 23, in response to a color burst synchronizing signal applied to the system 23 by the amplifier 26, to have a specific relation to the modulated subcarrier wave 130 786,236 786,236 S signal amplified by the unit 26 The frequencies of -the subcarrier wave signal and the signal developed by the generator 18 are maintained equal and the phase relation is so maintained that the signal directly applied to the apparatus 16 from the generator 18 is in phase with the modulation phase of the subcarrier wave signal of one of the signals to be derived in the apparatus 16 For example, the phase of the signal directly applied from the generator 18 is in phase with the modulation phase of the R-Y color-difference signal In such case, the design of the phase-modifying circuit 19 is such as to delay the phase of the signal developed in the output circuit of the generator 18 under consideration so that in another detector in the apparatus 16 such delayed signal is in phase with the modulation phase of the B-Y color-difference signal. The phase-modifying circuit 34 controls the phase of the signal translated therethrough so that such phase occurs in coincidence with that phase of the applied chrominance signal at which the I-modulation component occurs and thereby causes the demodulator 31 to be conductive in synchronism with the I-modulation phase The circuit 39 controls the phase of the reference signal translated therethrough so that the I-modulated signal developed in the output circuit of the modulator 33 and applied to the adder circuit 29 is in phase with the I-modulation phase of the signal translated through the units 27 and 28 and also applied to the adder circuit 29.

Operation of Wave-Signal Modifying Apparatus of Fig 1. Considering now the operation of the signal-modifying apparatus 15 of Fig 1, a chrominance signal, specifically the modulated subcarrier wave signal and its side bands extending over the range of 2 1-4 1 megacycles, is translated through the amplifier 26 Such subcarrier wave signal with its side bands is diagrammatically represented by Curve A of Fig 2 and has a mean frequency of approximately 3 6 megacycles, a double side-band region between 3 1 and 4 1 megacycles, and a single side-band region between 2 1 and 3 1 megacycles. The double side-band region includes the modulation components I and Q at quadrature phases of the subcarrier wave signal and these components are translated through the network 27 and the buffer amplifier 28 and applied to an input circuit of the adder circuit 29 Such translated double side-band component is represented by Curve B of Fig 2 The single side-band component, represented by Curve C of Fig 2, is translated through the network 30 and applied to an input circuit of the synchronous demodulator 31 A sine-wave signal having the same frequency as the subcarrier wave 65 signal, that is, a frequency of approximately 3.6 megacycles and in phase with the Isignal modulation phase of the modulated subcarrier wave signal is also applied to an input circuit of the synchronous demodulator 70 31 The pair of applied signals heterodyne in the demodulator 31 to develop a beatfrequency signal having a band width of 0.5-1 5 megacycles and representative of that portion of the I signal which effects single 75 side-band modulation of the subcarrier wave signal The derived component, represented by Curve D Qf Fig 2, is translated through the network 32 and applied to an input circuit of the balanced modulator 33 The 80 signal in the output circuit of the phasemodifying circuit 39 is applied to the other input circuit of the balanced modulator 33. The derived I-signal component, represented by Curve D of Fig 2, modulates the 3 6 85 megacycle signal applied to the modulator 33 to develop a pair of side-band components such as represented by Curve E of Fig 2 The 3 6 megacycle reference signal modulated in the unit 33 is controlled by 90 the phase-modifying circuit 39 to be in phase with the I-modulation component of the signal translated through the units 27 and 28 Consequently, in the adder circuit 29 the signal developed in the output circuit 95 of the modulator 33, and represented by Curve E of Fig 2, combines with the signal translated through the units 27 and 28, and represented by Curve B of Fig 2, to develop a resultant subcarrier wave signal such as 100 represented by Curve F of Fig 2 The resultant subcarrier wave signal is double side-band modulated by both the Q and I modulation components Because of such double side-band modulation, the I and Q 105 signals, or any components defined by

combination of such I and Q signals and derivable from the subcarrier wave signal, for example, the R-Y and B-Y modulation components, may be directly derived in the 110 synchronous detection apparatus 16 with all the double side-band benefits formerly only available by deriving the I and Q components, that is, such signals may be derived without causing the suprious effects resulting 115 from the cross-talk deficiencies of single side-band modulation to be developed. Description and Explanation of Operation of Wave Signal Modifying Apparatus of Fig3 120 Though the modifying apparatus 15 of Fig 1 is effective to permit direct derivation of the R-Y and B-Y or other color-difference signals directly from the subcarrier wave signal without intermediate derivation of I 125 and Q color-difference signals, the apparatus may require more circuit elements and circuit components than desirable for the benefits obtained The apparatus of Fig 3 786,236 Srequires -less components to effect the result obtained in the apparatus 15 of Fig 1. Since many of the circuit components in the apparatus of Fig 3 are the same as components in the apparatus of Fig 1, such components are identified by the same reference numerals. In the apparatus of Fig 3 the channel for translating the signal with a band width including at least the double side-band portion of one of the modulation components includes a band-pass filter network 40 having a pass band of 2 1-4 1 megacycles Such network is effective to translate not only the 3 1-4 1 double side-band portion of the modulated sub-carrier wave signal but also the single side-band portion between the frequencies 2 1 and 3 1 megacycles Additionally, in the apparatus of Fig 3 the signalmodifying circuit includes a balanced modulator 42 and a filter network 43 having a pass band of 4 1-5 1 megacycles coupled, in the order named, between the output circuit of the filter network 30 and an input circuit of the adder circuit 29 A second harmonic amplifier 41 is coupled between the output circuit of the phase-modifying circuit 34 and an input circuit of the balanced modulator 42 The second harmonic amplifier 41 is effective to develop a signal having approximately a frequency of 7.2 megacycles and in phase with the modulation phase of the I signal on the subcarrier wave signal translated through the network 30 The balanced modulator 42 may be a conventional modulator. In operation, the modifying apparatus of Fig 3 translates the modulated subcarrier wave signal partially double side-band modulated and partially single side-band modulated through the network 40 and the buffer amplifier 28 for application to an input circuit of adder circuit 29 The upper side band in the region of 4 1-5 1 megacycles corresponding to the side band in the region of 2 1-3 1 megacycles is not translated through the units 28 and 40 or prior stages in the

receiver or transmitter due to the upper frequency cutoff characteristics of the system through which the television signal including such modulated subcarrier wave signal is conventionally translated. The components of the lower side band in the region of 2 1-3 1 megacycles are translated through the network 30 and applied to an input circuit of the balanced modulator 42 A 7 2 megacycle sine-wave signal in phase with that modulation phase of the subcarrier wave signal at which the I signal modulates such wave signal, that is, with a peak of the second harmonic signal in co-incidence with the I-modulation phase, is also applied to the modulator 42 The 2 13.1 megacycle component heterodynes with the 72 -megacycle signal in the modulator 42 to develop a component having the frequency range of 4 1-5 1 megacycles The latter component corresponds to the upper side band of the 2 1-3 1 megacycle component The 4 1-5 1 megacycle component 70 is applied to an input circuit of the adder circuit 29 wherein it combines with the subcarrier wave signal applied to the other input circuit of the adder circuit 29 to develop a resultant wave signal having double side 75 band modulation for both the I and Q components This double side-band modulated subcarrier wave signal is utilized in detection apparatus such as the unit 16 in Fig 1 in the manner previously described herein 80 Though the above apparatus has been described as utilizing a balanced modulator 42, an unbalanced modulator may be employed if only components having the double sideband frequencies of 3 1-4 1 megacycles are 85 translated through the units 40 and 28 and the single side-band components in the range of 2 1-3 1 megacycles are translated through the units 30, 42, and 43 by modifying the pass band of network 43 to cover at least 90 the ranges of 2 1-3 1 and 4 1-5 1 megacycles. Description and Explanation of Operation of Wave-Signal Modifying Apparatus of Fig 4. Though the apparatus of Fig 3 requires 95 less circuit components than that of Fig 1 to effect the same result, it may sometimes be beneficial to utilize a wave-signal modifying apparatus requiring even less circuit components than those described with reference 100 to Fig 3 The apparatus of Fig 4 employs a minimum of circuit components for modification of the subcarrier wave signal from one partially single side-band modulated to one including only double side-band modu 105 lation Those circuit components in the apparatus of Fig 4 which are identical with components in the apparatus of Fig 1 are indicated by the same reference numerals as used in Fig1 110 Referring now to the apparatus of Fig 4, the channel for translating the wave signal with a band width including at least the double side-band portion of one of the modulation components comprises a delay 115 line 52 The delay line

52 is in parallel circuit with a pair of inductively coupled tuned circuits 51 and 53 having a pair of terminals thereof coupled by means of the delay line 52 The terminal of the tuned 120 circuit 51 remote from the delay line 52 is connected to an output circuit of the chrominance-signal amplifier 26 through a condenser 50 while a center tap of the tuned circuit 53 is coupled to detection apparatus 125 such as the unit 16 of Fig 1 The circuits 51 and 53 are broadly resonant at the mean frequency of the subcarrier wave signal to have a pass band for the coupled circuits -786; 236 megacycles is applied through the condenser to the resonant circuit 51 and through the circuit 51 to the input circuit of the delay line 52 Such applied subcarrier wave signal is translated through the delay line 52 70 with some delay to develop across the output circuit thereof a subcarrier wave signal corresponding to the applied subcarrier wave signal delayed by a specific amount The subcarrier wave signal applied to the reson 75 ant circuit 51 is applied to the resonant circuit 53 to induce in the latter resonant circuit a subcarrier modulated wave signal effectively having frequencies over the range of 3.1-4 1 megacycles and inverted in-phase 80 with respect to the signal developed in the output circuit of the delay line 52 Consequently, the subcarrier wave signal developed between the anode of the tube 54 and ground effectively has no frequency components in 85 the range of 3 1-4 1 megacycles, having only components in the range of 2 1-3 1 megacycles such as represented by Curve C of Fig 5 At the tap on the inductor of the resonant circuit 53, since this tap with res 90 pect to either end terminal of the resonant circuit 53 has less impedance than the circuit 53 and therefore less than the output impedance of the delay line 52, the inverse signal is not of sufficient magnitude to effect 95 complete cancellation of the signal developed at the output circuit of the delay line 52. Consequently, at such tap a signal is developed such as represented by Curve C of Fig 5 but having components in the fre 100 quency range of 3 1-4 1 megacycles such as represented by Curve C' of Fig 5. The manner in which a subcarrier wave signal, having a frequency-amplitude characteristic such as represented by Curve C of 105 Fig 5, is developed in the resonant circuit 53 has just been described To understand how a periodically conductive diode, such as diode 54 conductive in-phase with the Q axis of the subcarrier wave signal, operates 110 to develop a resultant subcarrier wave signal double side-band modulated by both the Iand Q-modulation components, it is initially helpful to consider some of the characteristics of a single side-band component such 115 as the I component in the range of 2 1-3 1 megacycles A reasonably thorough consideration of single side-band transmission has been presented in an article entitled

"Effect of the Quadrature Component in 120 Single Side Band Transmission" at pages 63-73, inclusive, of The Bell System Technical Journal for 1940 This article supports the proposition that the power or energy of a single side-band component -is distributed 125 substantially equally in quadrature components, that is, in amplitude-modulation and phase-modulation of the carrier wave signal resulting in the amplitude-phase ambiguity attributed to single side-band tranis 130 of approximately 3 1-4 1 megacycles, that is, a pass band equivalent to the double sideband portion of the subcarrier wave signal. The coupled tuned circuits 51 and 53 have an over-all phase delay inherent in such circuits and the delay of the delay line 52 is made equal to that of circuits 51 and 53. In order to provide a load circuit for the 4.1-5 1 megacycle components to be developed, the delay line 52 is designed to have a pass band of 2 1-5 1 megacycles, though signals having only the frequency range of 2.1-4 1 megacycles are translated therethrough from the output circuit of the amplifier 26 The impedances of the circuits 51 and 53 and the terminating impedances of the delay line 52 may be made equal for convenience The pass band of the delay line 52 is represented by Curve A of Fig 5 while that of the coupled tuned circuits 51, 53 is represented by Curve B of Fig 5 The phase translation characteristic of the coupled circuits 51 and 53 is the inverse of that for the delay line 52 Consequently, signals developed in the output circuit of the delay line 52 which correspond to the signals developed in the tuned circuit 53 are equal and opposite in magnitude Such correspondence occurs over the band of frequencies 3 1-4 1 megacycles Therefore, the over-all pass band of the system including the units 51, 52, and 53 is such as represented by Curve C of Fig 5. The signal-modifying circuit of Fig 4 includes a diode 54 having the anode thereof coupled to the tuned circuit 53 and the cathode coupled in series through a tuned circuit 56 and a biasing circuit 57 to ground. The circuit 56 is resonant at the second harmonic frequency of the subcarrier wave signal, that is, at approximately 7 2 megacycles An output circuit of the referencesignal generator is coupled through a phasemodifying circuit 58 and a second harmonic amplifier 59 to a resonant circuit 55 tuned to approximately 7 2 megacycles and which is inductively coupled to the resonant circuit 56 The phase-modifying circuit 58 is arranged to delay the phase of the signal developed in the generator 18 so that the 7.2 megacycle signal in the cathode circuit of the diode 54 is in phase with the phase of the subcarrier wave signal at which the Q-modulation component occurs The biasing

circuit 57 develops a positive potential during conduction periods of the diode 54 which tends to maintain the diode nonconductive The potential of the 7 2 megacycle signal is such as to render the diode 54 conductive at the times of the negative peaks thereof damping any signal then being applied to the anode of the diode 54. Considering now the operation of the apparatus of Fig 4, the subcarrier wave signal modulated over the range of 2 1-4 1 786,236 mission Effectively a single side-band component can be considered to have two sets of side bands, one being in-phase and the other in quadrature-phase with the carrier wave signal This relationship is represented by the spectrum diagrams of Figs 6 a-6 d, inclusive, and the related vector diagrams of Figs 7 a-7 d, inclusive, representing the I single side-band component in the frequency region of 2 1-3 1 megacycles The reference axis in the vector -diagrams of Figs 7 a-7 d, inclusive, is that phase of the subearrier wave signal at which the I signal should effect amplitude-modulation. In Fig 6 a, the relationship in frequency and amplitude of the single side-band component to the subcarrier wave signal is represented and Fig 7 a is a vector representation of the magnitude and phase of such single side-band I component Without disturbing the validity of representation, the single side-band component represented by Figs 6 a and 7 a may be represented as including an upper side-band component of equal energy half of which is in a positive sense and the other half in a negative sense so that the two halves cancel each other leaving only the single side-band component. Figs 6 b and 7 b represent the single sideband component with the addition of such upper side-band component It is obvious that in Figs 6 b and 7 b the halves of the added upper side-band component cancel each other and, therefore, the representations of Figs 6 b and 7 b are as valid as the representations of Figs 6 a and 7 a However, the representations of Figs 6 b and 7 b assist materially in indicating some fundamental aspects of a single side-band component as verified from experiments described in the article referred to above. The side-band components represented by Figs 6 b and 7 b are separable into two sets of equal side-band components One of such sets is represented by Figs 6 c and 7 c and includes the side-band components symmetrically disposed about the reference axis and thus these figures represent sideband components which effect pure amplitude-modulation of the I-modulation phase of the subcarrier wave signal The other set of side-band components is represented by Figs 6 d and 7 d and is symmetrically disposed about an axis in-quadrature with the reference axis or, more specifically, that axis of the subcarrier wave signal at which the Q signal effects amplitude-modulation of such subcarrier wave signal Consequently, the side-band components represented by Figs

6 d and 7 d represent amplitude modulation of the subcarrier wave signal at the Q axis and thus represent cross talk of the I-modulation signal into the Q-modulation signal This is the undesirable cross talk eliminated by means of wave-signal modifying apparatus in accordance with the present invention. The signal developed across the diode circuit including the networks 56,57 and the diode 54 has the spectrum represented by 70 Curve C of Fig 5 unmodified by the portion represented by Curve C' The diode 54 is normally nonconductive due to the bias developed in the network 57 The 7 2 megacycle signal applied by means of the 75 ' resonant circuit 56 to the cathode of the diode 54 is, as has been explained previously, phased so that the negative peaks thereof are in phase with the Q-modulation axis of the modulated subcarrier wave signal 80 applied to the anode of the diode Since, as represented by Curve C of Fig 5, the subcarrier wave signal applied to the diode 54 includes no Q-modulation components, that is, includes no energy in the region of 85 3.1-4 1 megacycles, the diode 54 cannot respond to components in this region and, therefore, has no effect on the double sideband Q components of the subcarrier wave signal However, the applied subcarrier 9 a wave signal does include components in the region of 2 1-3 1 megacycles, these components representing the single side-band modulation effected by the I signal The diode 54 is, as has been described, rendered 95 conductive in phase with the Q-modulation phase and thus is rendered conductive in phase with the components represented by Figs 6 d and 7 d Consequently, such components are effectively shunted to ground by 100 the conducting diode leaving only those I components which effect amplitude-modulation of the subcarrier wave signal at the proper phase and which are represented by Figs 6 c and 7 c Thus, effectively the sub 105 carrier wave signal is modified to have upper and lower side-band modulation components, such as represented by Figs 6 c and 7 c, in place of what previously was only single side-band modulation of the sub 110 carrier wave signal Consequently, the signal developed at the tap terminal of the resonant circuit 53 and including I and Q double side-band components for the region of 3 14.1 megacycles, as represented by Curve C'115 of Fig 5, and I double side-band components in the regions 2 1-3 1 and 4 1-5 1 megacycles, as represented by Figs 6 c and 7 c, is a subcarrier wave signal fully double side-band modulated by both the Q and I 120 components This signal is utilized in the detection apparatus, such as the unit 16 of Fig 1, in the manner previously considered herein The signal developed at the tap terminal of the resonant circuit 53 is 125 employed to provide a wave signal modulated to equal levels of the I and Q components This is accomplished because the level of the signal at the tap terminal is a fraction of that at the delay-line

termination 130 786,236 786,236 9 for the double side-band components in the frequency range of 3 1-4 1 megacycles, for example, a level of one-half that at the delay line As indicated by the levels of the sideband components represented by Fig 6 c, the I-modulated portion of the subcarrier wave signal, that is the components in the frequency ranges of 2 1-3 1 and 4 1-5 1 megacycles, are attenuated by the signalf O modifying process to be approximately onehalf the level of the I-modulated side-band portion represented by Fig 6 a In order to retain equality of modulation level, it is desired that the double side-band modulated portion of the wave signal be similarly attenuated, that is, the portion in the range of 3 1-4 1 megacycles, and this is effected by employing the signal at the tap terminal of the tuned circuit 53 If the output signal is taken from the delay line only, then the components in the range of 3 1-4 1 megacycles are twice the intensity of those in the ranges 2 1-3 1 and 4 1-5 1 megacycles This might be desirable to provide increased gain for the low-frequency derived components, that is, to provide low-frequency boost if such is found to be beneficial. The development of the upper side band of the I component may also be considered as a heterodyning operation in which the I-signal side-band components in the range of 2 1-3 1 megacycles are heterodyned with the 7 2 megacycle signal in the cathode circuit of the diode 54 to develop the 4 1-5 1 megacycle components When so considered, the operation of the diode 54, conductive in-phase with the Q components, is such as to damp out the Q components at a 7 2 megacycle rate The shunted Q components heterodyne with the 7 2 megacycle switching of the diode to develop an upper side-band component. Though there have been described herein circuits for converting a subcarrier wave signal at least partially single side-band modulated to another subcarrier wave signal entirely double side-band modulated and from which R-Y and B-Y modulation components may be directly derived with all the benefits of initially deriving I and Q components, it should be understood that the invention is broadly directed to the conversion of one type of wave signal to another and not to the conversion of a specific wave signal to a specific other wave signal for the purpose solely of deriving the specific modulation components described herein The resultant wave signal double side-band modulated may be utilized in any 460 manner desirable and any modulation components may be derived therefrom, such as the color-difference signals described herein or others, and such components will effectively have the benefits of double side-band s 65 modulation and be free from the deficiencies and limitations of single side-band modulation Additionally, though the description herein has been directed to utilization of the invention with three-gun picture

tubes, modifying apparatus in accordance with the present invention also has extensive utility in single-gun picture tubes where the color detection occurs within the picture tube. Such signal-modifying apparatus operates in a manner analogous to that previously described to develop the complementary side band of the single side band and to modify the wave signal into a resultant double sideband wave signal This signal-modifying apparatus may be employed in addition to apparatus which modifies the subcarrier and luminance signal to the form required for one-gun tubes.

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* GB786237 (A)

Description: GB786237 (A) ? 1957-11-13

Process for the preparation of hydrogen peroxide



BE543261 (A) DE1025396 (B) FR1137161 (A) US2904478 (A) BE543261 (A) DE1025396 (B) FR1137161 (A) US2904478 (A) less Translate this text into Tooltip



AMENDED SPECIFICATION Reprinted as amended in accordance with the Decision of the Superintending Examiner acting for the Comptroller-General, dated the eighteenth day of October, 1960, under Section 33, of the Patents Act, 1949. PATENT SPECIFICATION DRAWINGS ATTACHED Date of Application and filing Complete Specification: Dec 6, 1955. So | r No 34886/55. Application made in Germany on Dec 8, 1954. Complete Specification Published: Nov 13, 1957. Index at acceptance:-Class 1 ( 2), A 7. International Classification:-C Olb. COMPLETE SPECIFICATION Process for the preparation of Hydrogen Peroxide We, DEUTSCHE GOLD UND SILBERSCHEIDENSTALT vormals Roessler, a German Joint Stock Company, of 9, Weissfrauenstrasse, Frankfurt am Main, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - The present invention relates to a process for the preparation of hydrogen peroxide by the electrolytic oxidation of sulphuric acid or a sulphate and decomposition of the persulphuric acid or persulphate formed at the anode. It is known to prepare hydrogen peroxide by the anodic oxidation of sulphuric acid or a sulphate hydrolysis of the persulphuric acid or persulphate so formed and fractional distillation end/or condensation of the resulting solution of hydrogen peroxide In this process hydrogen is produced at the cathode and this has hitherto not as a rule been used, for various reasons, in the technical working of the electrolytic process. It is also known that hydrogen peroxide can be obtained from hydrogen by a number of methods of which the following can be mentioned. ( 1) The catalytic combustion of hydrogen with molecular oxygen. ( 2) The combustion of hydrogen with molecular oxygen by means of a silent electrical discharge. ( 3) The reaction with hydrogen of an organic compound such as anthraquinone, or an alkyl derivative thereof such as 2 methyl anthraquinone, or azotoluene which forms, by such lPrice 3 s 6 d l reaction, a compound with readily separable hydrogen atoms and subsequent autoxidation of the latter compound with molecular oxygen. ( 4) Reduction of cadmium hydroxide, anialgamation of the resulting metallic cadmium with mercury and reaction of the amalgam with water

in the presence of molecular oxygen. In any of these methods the molecular oxygen may be in the form of gaseous oxygen itself or of gases containing oxygen, such as air. By these methods it is possible to obtain hydrogen peroxide only in dilute solution whose working up is expensive; but it becomes economical, in an electrolytic process in which hydrogen peroxide is produced from persulphuric acid or a persulphate at the anode, to work up such a solution. According to the present invention, therefore, there is provided a process for the preparation of aqueous hydrogen peroxide by the electrolytic oxidation of sulphuric acid or a sulphate and decomposition of the persulphuric acid or persulphate formed at the anode in which the hydrogen produced at the cathode is employed for the preparation of aqueous hydrogen peroxide by a method known per se and the aqueous hydrogen peroxide produced from the cathode hydrogen and the persulphuric acid or persulphate solution are treated in a common process for the working up of the hydrogen peroxide, the working up being effected by fractional distillation and/or condensation The combined working up of aqueous solution of hydrogen peroxide produced from the cathode hydrogen, although this is comparatively weak in hydrogen per786,237 oxide, and that obtained by decomposition of the persulphuric acid or a persulphate, gives a self-contained process giving a good yield of hydrogen peroxide and high energy efficiency. It is desirable, in carrying out the process, to recover as completely as possible and particularly in a pure form, the hydrogen formed on the cathode, which can readily be done by the process of Specification No 735,195. It is particularly important to employ the hydrogen in a high degree of purity when it is reacted with an organic substance which forms a compound with readily separable hydrogen atoms Since such compounds, when treated with molecular oxygen for the production of hydrogen peroxide are converted again to the starting materials, the latter can be used cyclically by further reaction with hydrogen. Similarly, when the hydrogen is used for the reduction of cadmium hydroxide, the decomposition of the cadmium amalgam which gives rise to hydrogen peroxide also yields cadmium hydroxide again which can thus be used cyclically as illustrated by the following equations. Cd(OH)2 + H 2,-Cd+H 20 Cd + Hg Cd(Hg) Cd(llg) + 2 H 20 + O 2->Cd(OH)2 + H 202 (+ Hg) A process using the hydrogen from the cathode gives a hydrogen peroxide solution of lower concentration than that of the solution obtained by decomposition of the anodically oxidised solution It is therefore very advantageous to work up such a dilute solution toaether with the anodically oxidised solution.

The fact that it is no longer necessary to concentrate these more dilute solutions separately, by means of organic compounds, for example, means that there is less need to take account of undesired secondary reactions. In the working up by distillation of the solution obtained by decomposition of the anodically oxidised solution, relatively large quantities of steam become available, since the steam is generally evolved at a concentration of 7-10 % hydrogen peroxide The heat content of these large quantities of steam may be utilised in a simple manner and favourably from the point of view of energy for the concentration of the dilute peroxide solutions obtained from the cathodic hydrogen Thus quite dilute solutions may be utilised effectively by simply adding them as a reflux to vapours from the solution obtained by decomposition of the anodically oxidised solution according to a preferred method of carrying out the invention. EXAMPLE 1 Electrolysis is carried out in a persulphuric acid plant producing 1,000 Kg of hydrogen peroxide of 25 % concentration by weight in 24 hours This plant has a current capacity of 5 x 7000 Amp = 35000 Amp for the anodic and cathodic current operation According to the process of Specification No 735,195 electrolysis is effected with a voltage of 4 35 volts per cell and with 70 % overall yield for the anodic process (current yield x distillation yield), there is a consumption of 10 k-W direct current for each Kg of 100 % hydrogen peroxide produced. With the stated quantity of current 14 64 cbm of hydrogen gas per hour simultaneously produced at the cathodes, of which more than % can be recovered according to the process of Specification No 735,195. In the working up by distillation of the anodically produced persulphuric acid, which, under the above stated conditions, amounts to approximately 6,500 litres of 32 % H 2520 in 24 hours, a reflux of about 850 litres occurs during fractional condensation to produce hydrogen peroxide of 35 % by weight This quantity of liquid which is condensed from the waste vapour may be replaced by a solution of hydrogen peroxide obtained from the hydrogen liberated at the cathode, the hydrogen peroxide content of which is then brought to % by weight almost without loss or cost. Moreover the heat of the exhaust steam can be utilised by pre-concentrating the solution of hydrogen peroxide obtained from the cathodic hydrogen in a heat exchanger and then adding the solution to the reflux during the fractionating The condensed exhaust vapours can then be used for diluting the electrolyte from the anode process after the distillation. As already indicated, the cathodic hydrogen may be used to make hydrogen peroxide by an autoxidation process employing an alkyl

anthrahydroquinone in a suitable solvent The alkyl anthrahydroquinone which is first formed is oxidised by means of oxygen or oxygencontaining gases and the alkyl anthraquinone which is recovered can be re-used. In the alkyl anthraquinone process approximately 80 cbm of hydrogen gas are required for 100 Kg 100 % H 202 The persulphuric acid process of this example yields 14 64 cbm hydrogen gas per hour, of which 95 % can be utilised This is 13 9 cbm per hour or 334 cbm in 24 hours, so that about 400 Kg 100 %/ hydrogen peroxide, that is to say, more than from the anode process, can be obtained The hydrogen peroxide solution obtained from the alkyl anthraquinone process is worked up in the distillation process of the anodic product. If it is considered that the cathodic hydrogen, apart from the costs of the apparatus to utilise it, is yielded without cost and also a great part of the heat is available for the concentration of the solutions, it will be seen that the combined use of the two processes yields a very cheap process of preparing hydrogen peroxide In addition it enables the concentration of the hydrogen peroxide solu786,237 roxide obtained from this process is reduced to cadmium metal by the cathodic hydrogen at temperatures below 3000, and this dissolved in mercury and can thus be used cyclically. EXAMPLE 3 This example illustrates the combination of the electrolytic process with catalytic combustion of hydrogen to form hydrogen peroxide, and is shown in Fig 2 of the accompanying drawings In Figure 2 the electrolysers for obtaining persulphuric acid or its salts are indicated by 21 The cathodically produced hydrogen is collected in the pipe line 22 and the anodically oxidised solution flows through 23 into the preheating column 24 (in which mainly the hydrolysis and a part of the distillation is undertaken) and from there into the column where the formed hydrogen peroxide is expelled by direct steam At the foot of the column, at 26, the sulphuric acid is drawn off and returned to the electrolysers through 27 in the cycle The vapour mixture from the column 25 flows through 28 into the fractionating condenser 29 whence aqueous hydrogen peroxide is removed at 220 The steam is condensed at 221 The cathodically produced hydrogen flows through 22 into the catalyst oven 222 into which air or oxygen is introduced at 223 The hydrogen peroxide produced is passed together with water, through the connection 224 at 225 as a reflux, to the fractionating condenser 29 and enriched there.

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* GB786238 (A)

Description: GB786238 (A) ? 1957-11-13

Improvements in or relating to composite catalysts for use in the hydrationof olefins and to the preparation of alcohols thereby



DE1042561 (B) DE1042561 (B) less Translate this text into Tooltip



COMPLETE SPECIFICATION Improvements in or relating to Composite Catalysts for Use in the Hydration of Olefins and to the Preparation of Alcohols Thereby. We, N. V. DE BATAAFSCHE PETROLEUM MAATSCHAPPIJ, a company organised under the laws of The Netherlands, of 30 Carel van Bylandtlaan, - The Hague, The Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to the preparation of a composite catalyst for use - in the preparation of alcohols by the vapour-phase hydration of

olefins. It is known that olefins can be reacted with water to form alcohols, the reaction being conducted in the vapour phase at high pressures and moderately eleyated temperatures, and in the presence of a suitable catalyst. U.K. Patent Specification No. 651,275, for example, describes such a process wherein a composite catalyst comprising a solid porous siliceous support incompletely saturated with an aqueous solution of phosphoric acid of specified concentration is employed. This process although successfully used in commercial operations, has been found to be not entirely satisfactory, for reasons which are attributable to the particular composite catalyst hitherto employed. The requirements for a successful composite catalyst for use in the hydration of olefins include: A. The catalyst must actively and selec tively promote the hydration of olefins to alcohols without causing concurrent for mation - of excessive amounts of polymers, tars and cokes, or malodorous by-products, such as aldehydes. B. The catalyst must have a sufficiently long life with respect to its catalytic activity. C. The catalyst must be sufficiently strong mechanically to withstand crushing and other forces tending to cause its attrition during preparation and use. D. The catalyst must be chemically stable and inert with respect to the various reactants and reaction products, as well as to the materials of construction with which it comes into contact. It has been found that the particular material employed as the carrier-determines the character of the final composite catalyst with respect to factors C and D, and determines to a great extent factors A and B, as well, Only relatively few materials have been found to provide all the above requirements to a practical degree, and even in these cases there has been need for improvement. Composite catalysts comprising silica gel as the carrier have been found to exhibit high

activity levels with good selectivity, but they shave low mechanical strength and insufficient resistance to attritional forces. Qther types of siliceous materials, various aluminas, cokes and other forms of carbon have been employed as the carrier material with varying degree of success. The most useful of all the carrier materials heretofore employed have been found to be certain forms of calcined diatomaceous earth. -These calcined diato maceous earths are composed primarily of silica and/or hydrated silica in the form of complete or incomplete diatoms skeletons, the diatom skeletons being cemented or bound together with clay or clay-like materials. Catalysts prepared by impregnat ing these materials with phosphoric acid of the correct concentration have been found to have satisfactory activity levels, good selectivity and high mechanical strength. However, for several reasons calcined diatomaceous earth materials of this kind have not proved entirely satisfactory for use as the carrier material. The clay binding material contains metallic compounds (primarily iron and aluminium oxides and/or silicates) which are quite soluble in phosi phorio acid of the concentration employed in olefin hydration catalysts, at the tempera tures normally employed in effecting such hydrations. The solubility of these compo nents of the binding material of the carrier in the impregnating acid causes several serious problems during the use of the corre sponding composite catalysts. First, the alteration of the chemical composition of the binding material reduces its effectiveness as a binder, and seriously impairs the mech anical strength of the final catalyst. Both the mechanical strength of the catalyst and its resistance to abrasion are affected, so that during operation it tends to disintegrate at an undesirably rapid rate. This break-down of the catalyst increases the pressure drop across the catalyst bed and tends to cause

the gaseous reaction mixture to channel i.e., the bed tends to plug-up, leaving only restricted paths through which the gases may flow. - This reduces the effective area of the catalyst and the intimacy of contact between the gases and the catalyst surface; the effi ciency of the catalyst is lowered accordingly. A further difficulty encountered is that the finer particles of the catalyst tend to disperse in the gaseous reaction mixture and pass with it from the reactor into subsequent process equipment. This causes additional loss of catalyst and necessitates clean-up of the other equipment. The over-all result is that both the useful life and the efficiency of the catalyst are reduced at an undesirably rapid rate. Secondly, these composite catalysts have a tendency to "bleed" during use. That is to say, a liquid or semi-liquid material tends to seep from the catalyst. This seepage material appears to consist primarily of an aqueous solution of free phosphoric acid containing a substantial concentration of the phosphates of iron and aluminium. It tends to flow slowly through the catalyst bed and in part, at least, out of the reactor. A part of the fine particles produced by disintegration of the carrier material, together with particles of carbonaceous material formed by cracking of the olefin, becomes suspended in the seepage material. The fluidity of the resulting mixture is markedly dependent upon the temperature of the mixture, so that even a relatively small drop in the temperature of the mixture causes it to set to a hard, extremely tenacious solid. Thus, where the mixture passing through the catalyst bed encounters any "cool" zone, or where the reactor temperature falls more than a few degrees, the seepage material - hardens, effectively plugging up the catalyst bed. The area of plugging often grows since the original plug disturbs the flow pattern of the gases, extending the area of the cool zone. This effect likewise reduces the efficiency of the catalyst, increases the pressure drop across the catalyst bed and causes channelling of the gaseous reaction mixture. In many in stances, plugging of the reactor may become so severe that it is necessary to shut down the entire reactor and to replace the catalyst long before this would normally be required. The seepage material flowing from the re actor into the subsequent process equipment

also causes difficulties. For example the effluent gases from the reactor normally pass through pipes and valves to a heat exchanger wherein the product alcohol is condensed. The temperature in such piping is usually somewhat below the temperature in the re actor and the effluent gases are cooled sub stantially in the heat exchanger. Conse quently, the seepage material deposits out, coating the inner surfaces of the piping and the heat exchanger. At the least, such de posits increase the pressure drop across such apparatus, and seriously reduce the heat transfer coefficient of the heat exchanger. re quiring frequent cleaning of this equipment: in many cases, replacement of much of the process equipment immediately downstream from the reactor has been found necessary. A further disadvantage of these composite catalysts lies in the fact that hydration of the olefin over such catalysts is accompanied by the production of substantial amounts of carbonaceous materials. It is thought that these materials are formed by the cracking of the olefin reactant, and further that the cracking reaction is promoted by the iron present in the catalyst. Reduction of the iron content of the carrier would therefore be highly desirable, provided that this could be accomplished without concurrent reduction in the mechanical strength of the carrier. It has now been discovered that these difficulties can be overcome by the use of a composite catalyst prepared by impregnating, with an aqueous solution of phosphoric acid, a modified porous diatomaceous earth- carrier material prepared in a particular manner and having a structure unlike that of any material previously proposed in the art. According to the present invention a process for the production of a composite catalyst comprises saturating a porous, inert, diatomaceous carrier material with a strong aqueous solution of phosphoric acid, heating the resulting impregnated carrier material in an atmosphere containing water vapour having a partial pressure which is less than the partial pressure of water vapour in equilibrium with an aqueous solution of phosphoric acid at the temperature at which the heating is

effected, digesting the heated carrier material with acidified hot water having a pH less than about 1, washing the digested carrier material with hot water, drying the washed carrier material and impregnating the dried carrier material with an aqueous solution of phosphoric acid. This process results in a composite catalyst comprising an aqueous solution of phosphoric acid supported on a carrier consisting primarily of a porous diatomaceous material the diatom skeletons of which are coated with silica gel. By the use of a composite catalyst prepared in accordance with the present invention, an olefin may be converted to the corresponding alcohol at significantly higher initial and average conversion levels than has been possible heretofore. The formation of malodorous by-products andjor tarry or carbonaceous materials is substantially reduced. Substantially no seepage of metallic phosphates occurs, so that prolonged on-stream periods without significant reduction- in heat transfer coefficients of downstream heat exchangers or increase in pressure drop of subsequent transfer equipment are obtainable. No significant change in the mechanical strength of the catalysts of the present invention with prolonged use has been noted. Throughout this specification, the activity of the catalyst will be expressed in terms of the mole fraction (per cent.) of olefin converted to the alcohol per pass. Thus, where the term "catalyst activity level" or, simply, "activity level" is used, this term expresses the mole per cent. of olefin converted to alcohol per pass by the particular catalyst considered. The carrier material for preparing the catalysts of the present invention may be any of the various diatomaceous earth materials, by which term is meant any predominantly siliceous material composed primarily of the silica and/or hydrated silica skeletons of diatoms which are bonded together by a claylike binding agent, which materials may be formed into particles of regular size and shape having high - mechanical strength. Typical of these materials are the calcined diatomaceous earths manufactured by the Johns-Mansville Corporation and marketed under the trade name "Celite." ("Celite" is a Registered Trade Mark.) Especially desirable of this class of materials is the grade designated "Celite VIII," which is in the form of small pellets and has the following composition: Component Weight Per Cent Silica 86.1 Iron oxide 2.4

Alumina 7.3 Magnesia 1.2 Sodium oxide + potassium oxide 2.2 Titanium dioxide 0.2 Remainder- 0.6 It is preferred that the carrier material be in granular or pelleted form, and that the smallest dimension of said granules or pellets be at least about 1/32 of an inch. The preferred carrier materials of the composite catalysts of the present invention have an average pore radius of between about 3500 A and;about 6500 A and at least 5% of the pores have a radius of less than about 500 A Ordinarily not more than about 25% but at least about 1% of the total weight of the silica is in the form of silica gel, the remainder being in the form of complete or incomplete diatom skeletons. The silica gel usually is present in the form of a substantially uniform layer which is not thicker than about 1500 A over the surface of the diatom skeleton structure, - the layer intimately contacting the major portion of the surface area of said structure. - Carriers in which the thickness of the silica gel layer is between about 10 and about 250 , are preferred. The total porosity of these carriers (measured as the number of cubic centimetres of distilled water absorbed per gram of the carrier material at ordinary teinperatures and pressures) is between about 0.6 and about 1.1. The surface area of these carriers is between about 15 and about 40 square metres per gram. To prepare a catalyst in accordance with the present invention, the untreated material is first impregnated to substantial saturation with an aqueous solution of phosphoric acid containing a high concentration of the acid. For this purpose, there is preferably employed any aqueous solution of phosphoric acid containing at least about 70% by weight of phosphoric acid, such as the commercially available acid which contains approximately 85% by weight phosphoric acid. The impregnation of the carrier may be effected by immersing the carrier material in the acid for a sufficient time to ensure saturation of the material: a soaking period of between about 1/2 and 1 hour will usually be sufficient for this purpose. The impregnated carrier is then freed from excess acid by allowing it to drain thoroughly. After draining, the impregnated carrier is heated under carefully controlled and correlatedconditions of temperature and humidity, to effect solution of substantially all of the components of the clay-binding material and to effect solution of a controlled amount of the siliceous diatom skeletons. The heating may be effected at a

temperature between about 150 C and about 400 C, temperatures between about 225 C and about 325 C being preferred. Heating is effected in an atmosphere which contains sufficient water vapour to give a partial pressure less than the partial pressure of water vapour in equilibrium with an aqueous solution of phosphoric acid at the heating temperature. Thus, when the heating is conducted within the above-specified temperature range the atmosphere in which the heating is conducted should contain water vapour in an 'amount -such that the partial pressure of water vapour in that atmosphere lies between about 50 and about 500 millimetres of mercury. It has been found that a catalyst prepared from a carrier heated within the stated temperature range in an atmosphere in which the partial pressure of water is between about 150 and 300 -millimetres of mercury possesses optimum properties, i.e. such a catalyst promotes the conversion of olefins to alcohols at consistently high conversion levels, has excellent mechanical strength and exhibits substantially no seepage of metallic phosphates. The catalyst prepared according to this procedure contains but a small amount of iron and aluminium compounds. Usually the iron content (as iron oxide) is less than about 0.30,0, by weight of the carrier material, and the aluminium content (as the oxide) is somewhat less than about 3.0%. The form and location of these compounds in the carrier material are such that the compounds react with the impregnating acid slowly or not at all, under the usual operating conditions. The concentration and availability of the iron are such as not to promote cracking of the olefin so that the amount of carbonaceous materials produced during olefin hydration is substantially reduced. The total pressure within the system dur ing the heating is not a critical factor in the production of carriers of optimum characteristics, and atmospheric, subatmospheric or superatmospheric pressures are all satisfactory, provided the required humidity relationships are maintained. Operation at substantially atmospheric pressure is desirable from a practical standpoint. The time required for heating varies more or less directly with the temperature em ployed. For example, if the heating is carried out at about 100 C, the effect of the phosphoric acid is incomplete, even after 50-60 hours of heating, whereas if the tem perature is maintained at between about

250"C and about 350 C, heating for between about 2 and 8 hours will effect the reaction between the carrier and the phosphoric acid to substantial completion. In one case the heating was conducted. at 300"C and under 200 millimetres of mercury partial pressure of water for 1 hour and the catalyst activity was about 4.5 units. In comparison, where the heating was continued for 2 hours, the catalyst activity rose to about 5.1 units. Fur ther heating did not improve the catalyst activity significantly. When the heating.is carried out at lower temperatures, i.e. 150"C to 250 C, somewhat longer periods of heating -up to about 20 hours-will be required. Following heating the impregnated carrier material is digested with a controlled amount of hot water having a pH less than about 1 and it is believed that this digestion step has a dual effect of dissolving and removing-: the metallic phosphates present and also - of hydrolizing the dissolved silicyl phosphates in a controlled manner. The precise manner in which the silica gel resulting from hydrolysis of the silical phosphate is deposited in, upon or around the residual diatom skeleton structure is not known. The improved characteristics of the catalysts of the present invention do not appear to be only those which might be expected to arise from merely dcpositing silica gel on an inert carrier as by dipping the carrier in a silica sol and drying: the amount of silica gel deposited and/or its location on the diatom skeleton structure is such that the pore structure of the diatomaceous earth material is not significantly changed, yet the catalysts of the present inInvention exhibit improved characteristics. Whatever the disposition of the silica gel upon the; diatomaceous earth structure, the preceding description indicates the steps, determined empirically to be critical, in the production of the catalyst carrier material. The heated carrier material is generally digested at about 100 C with water having a pH of less than about 1.0 until substantially all of the metallic phosphates have been reremoved, and substantially all of the dissolved silicyl phosphates have been hydrolized to silica gel and deposited on the diatom skeletal structure. For providing the necessary acidity, there may be employed any strong mineral acid. Sulphuric acid is preferred for this purpose because of its low volatility. The volume ratio of. digestion solution to carrier material is generally above about 0.75:1. It is preferred in order to minimize the amount of mineral acid required, yet to obtain substantially complete removal of the metallic phosphates, that this volume ratio be maintained between about 1:1 and about 2:1. Volume ratios of below about 0.75:1 are undesirable since lower water to carrier ratios

promote the formation of thick gelatinous extracts of silica or silica gel. The pH of the solution is conveniently maintained within the desired range by emplaying a digestion solution having an initial pH between about 0.2 and about 0.5. If the pH is not maintained within the prescribed limits, the iron and aluminium phosphates tend to hydrolize and precipitate from the solution, coating the carrier material with a white crust which is very difficult to remove. This crust is highly undesirable, since it causes plugging of the pores of-the carrier material and cementation of the carrier particles. The digestion may be effected by immersing the carrier in the acidified water which is maintained at or slightly below its boiling point, and allowing the mixture to digest for a sufficient time to ensure substantially complete solution of the metallic phosphates. The temperature of the mixture is preferably not below about 85"C, but it is desirable that vigorous boiling be avoided during the diges tion, since the mechanical strength of the carrier material is then at its lowest level during the course of the pretreatment process, and vigorous boiling may cause undue attri tion of the carrier material. It is desirable, however, that the particles of carrier material be gently agitated during the digestion pro cess, thus preventing non-unilorm removal of the metal - phosphates and non-uniform hydrolysis of.the silicyl phosphates In some cases, especially where the pH of the leach solution approaches.0.7, agitation of the carrier material during leaching-is necessary to prevent formation of crusts of metaI hydroxides or hydrated oxides formed by hydrolysis of the metal phosphates. This digestion procedure should be carried out until the carrier. material is substantially free of metallic phosphates. Normally, sub stantially all of the soluble.materials will be leached from the carrier material and the silicyl-phosphate will be completely hydro 4sized in approximately one hour of digestion time, and in many cases substantially com plete solution and hydrolysis 'will be effected in about 30 minutes. It is desirable that the minimum digestion time be employed.

Following this first digestion stage, the carrier material is- drained and washed thoroughly in the manner described above for the first digestion stage, with the sole exception that the wash liquid consists of non-acidified hot water. The washing is preferably accomplished in several stages, each stage employing a fresh portion-of hot water. The washing should be continued until the carrier material is substantially free of acid. During this treatment any residual metallic phosphates will be removed and any remaining silicyl phosphate will be hydro lyzed. Following the washing stage, the carrier material is dried. For this purpose, any means common to the artHven drying, for example-may 'be' employed. The dried material is then impregnated with an aqueous solution of phosphoric acid in accordance with known procedures to form the superior composite catalyst of the present invention. The impregnation is carried out in the same manner as heretofore described iri preparing the carrier material for the heat treatment i.e. the dried carrier material is soaked in the aqueous phosphoric acid for 'a sufficient period of time to allow the carrier material to become saturated with the acid, the excess- acid is removed and the impreg nated carrier material is allowed to drain thoroughly. In generaI, a soaking period of from about to 1 hour will be found suffi cient, and an equal length of time for drain age normally prepares the catalyst' for - use. In use the - concentration of H3PO4 in the solution with which the carrier is impreg nated is generally at least 70% by weight and preferably is from about 75 to about 95 D/Q by weight. The concentration of HYPO4 in the aqueous acid solution supported on the carrier material during the olefin. hydration process is preferably maintained in the same concentration- range. Further, the can rier pore loading is preferably below about 90% and more preferably -is between about 70--80 /o . The term " pore loading "'indicates the relationship between the actual

amount of acid present on the carrier material and the maximum amount of acid with which it can become impregnated, it being understood that the carrier material and- the acid are in such case in the same physical states as under actual operating conditions. The maximum pore loading may.be determined experimentally, but for many purposes, it is more convenient and sufficiently accurate to calculate the maximum pore loading from the total porosity of the carrier and the specific gravity of the acid solution. For these calculations, the porosity af the carrier and the concentration of H,PO, in the acid solution have the same values that they have under actual operating conditions. At these desired pore loadings mentioned above catalyst activity is at its maximum and seepage is kept to a minimum. These conditions are most conveniently attained by an alternative treatment consisting of- saturating the treated carrier material-- (pore loading=100%} with a more dilute solution of' - phosphoric acid and operating under such conditions that part of the water content of the phosphoric acid solution is removed, bringing the -concentration of H3PO4- and the pore loading to the desired levels simultaneously. For this purpose, the dilute phosphoric acid used to impregnate the treated carrier material initially contains. somewhat less than 70% H3PO by weight. The acid concentration should not be below about 50% by weight, for otherwise the. final composite catalyst will be incompletely saturated with the acid. In general, an acid strength of about 55 to 65 % by weight has been found most suitable. The catalysts prepared in accordance with this process have been found to be relatively insensitive to changes in the water content of the reaction zone, and,therefore, may be used directly in the process for hydrating the olefin without any preliminary treatment. When employed in the process for effecting hydration of the olefin hereinafter described, the catalyst loses water until the strength of the phosphoric acid on the carrier rises until the solution of the acid contains at least about 70% by weight of phosphoric acid, which level is maintained - throughout the duration of the reaction. According to a further feature of the present invention a process for the preparation of an alcohol by direct hydration of an olefin, comprises contacting a gaseous mixture of an olefin and water at elevated temperature and pressure with a composite catalyst prepared as defined above, the temperature, pressure and molecular ratio of the reactants being controlled so that the aqueous solution of phosphoric acid supported on the carrier has a concentration of at least 705: by weight. By the use of a catalyst prepared in accordance with the present invention, the olefin conversion level is much higher than that

previously obtainable, and while the conversion level may decline with time, the rate of decline is much lower than with the olefin hydration catalysts known in the art. In effecting the hydration of an olefin, the various process conditions, i.e. temperature, pressure and molar ratio of water vapour to olefin vapour in the feed, are adjusted so as to bring the concentration of H3POr in the aqueous solution of phosphoric acid on the carrier to at least 70 O by weight as soon as possible after the process has gone on stream, and also whenever fresh acid is added as make-up during the hydration process. The hydration process is brought on stream by passing a heated gas through the catalyst bed until the reaction temperature is approached, whereupon the feed mixture of Normally, mixtures of the olefins with other hydrocarbon gases - may be - emplbyed. It is preferred that the other components of such mixtures be compounds which are substantially inert to the action of water vapour in the presence of the catalyst. The alcohol produced by the hydration of the olefin is condensed out of the gaseous effluent emerging from the catalyst bed, and by suitable choice of condenser and condensing temperature. The product alcohol and water vapour can be condensed with the condensation of but a minor amount, for example about 5 or 10%. of -by-product ether which is thereafter removed from the alcohol in known manner as by distillation. The remaining gaseous ether, together with unreacted gaseous olefin, is recycled through the system in admixture with additional quantities of olefin and water vapour, the process thereby being continuous. In the following Examples, Example I illustrates the preparation of a composite catalyst according to the process of the present invention and Examples II to VI, the use of such a catalyst in the hydration of olefines. EXAMPLE I A composite catalyst comprising phosphoric acid impregnated upon a siliceous carrier was prepared by the following procedure: 100 parts of a diatomaceous earth material designated by the manufacturer (Johns Mansville Corporation) as "Celite VIII," in the form of pellets of generally cylindrical shape measuring approximately 5/32 by 3/16 inch, were soaked for approximately one hour at room temperature in excess aqueous phosphoric acid containing 85% by weight H3PO4. The excess acid was then removed by allowing. the carrier material to drain for 1 hour. The impregnated carrier material was then heated in an oven at 300"C for 3 hours, the pressure being atmospheric and the atmosphere

surrounding the carrier material containing a partial pressure of water equal to approximately 200 millimetres of mercury. The material was then cooled and leached by digesting the material for 1 hour with acidified water maintained at 100"C. The water had an initial pH of 0.35, the acidity being furnished by the addition of sulphuric acid. The volume ratio of water to carrier material was approximately 1.5. The carrier material was then drained and the leaching repeated using fresh acidified water. The acidified water was then drained from the material and the leaching repeated twice more following the same procedure but substituting pure water for the acidified water. The carrier material was then drained and dried in an oven at about 125"C. It was then soaked in an excess of an aqueous solution of phosphoric acid containing 55 % by weight of HaPO4 for approximately one hour, after which itqwas drained for about 2 hours. EXAMPLE II 200 Parts of the catalyst prepared in Example I were charged to a reactor, and a gasedus mixture comprising water vapour and ethylene vapour in a molar ratio of 0.5:1.0 was passed through the catalyst bedat a VSVM of 27. The temperature of the catalyst bed was maintained between 275 C and 285"C. The total pressure. was 1000 pounds per square inch. No phosphoric acid was added during the run. The initial conversion level of ethylene to ethyl alcohol was 5.3 %. At the end qf 400 hours of operation the conversion level was 4.8%. Inspection of the catalyst during and at the end of the run showed that no carbon deposit or fines had resulted. Comparison of the catalyst's physical strength befbre and after the run showed a negligible physical strength loss. A duplicate run was conducted substituting for the catalyst specified above a catalyst comprising " Celite Vm" as received from the manufacturer impregnated with an aqueous solution of phosphoric acid of the same concentration as was employed with the treated carrier in preparing the catalyst in accordance with the invention. The initial conversion level in thins run was 4.2%, and the final conversion level was about 3.6%. EXAMPLE 111 The modified "Celite VIII"-phosphoric acid catalyst employed in Example II was re-impregnated with an aqueous solution of phosphoric acid containing 55% by weight H3PO4, and was employed in the hydration of ethylene under substantially the same conditions as indicated in Example II. The conversion level remained at 5.5% through out the duration of a 30 hour run. This value may be compared to the value 5.3 % obtained at,

the end of the first- 30- hours of the run reported in Example It. during the 30 hour period of the second continuous operation, there was no observed decline in the activity of the re-impregnated catalyst. EXAMPLE IV 200 parts of the catalyst prepared in Example I were charged to a reactor and heated in a stream of nitrogen for one hour, the catalyst bed temperature being approximately 275"C, and the total pressure being 1000 pounds per square inch gauge. A water vapour-ethylene vapour feed mixture in a molar ratio of 0.5:1 was then fed into the reactor. The activity of the catalyst after this treatment was 4.8, the catalyst bed temperature being approximately 275"C, and the feed rate being 47 VSVM. The run was repeated with 200 parts of fresh catalyst which was not subjected to the above pretreatment. The activity level of this catalyst was substantially the -same as that of the pretreated catalyst, i.e. approximately 4.6 ,' total conversion, illustrating the indifference of the catalyst of the present invention to start up procedures in which no water is present. EXAMPLE V The optimum operating temperature for the catalyst prepared by the- procedure of Example I - was determined by three runs each at a different catalyst bed temperature. The conditions, other than the temperature, were identical to those indicated in Example II. The following results were obtained ,EtAlvlene Run Teinperatie Conversion Level ('C) ( O) 1 250 4.7 2 275 5.4 3 300 4.5 EXAMPLE VI A run of extended duration was made in which the process was on-stream- for 100 days, under conditions which were substantially the same as indicated in Example II. The following data were obtained: <img class="EMIRef" id="026598819-00080001" /> - Initial (Start of run) - ,-. -- Final (End of run) Parts product Conversion Parts product Conversion per day level ( /O) - per day level ( O)

Treated carrier 14.5-15.5 4.24.6 ' ' - io - 3.2

Treated carrier -- . 16.5 5.3 15.5 - 4.6 What we claim is : - - 1. A process for- the production. of a composite catalyst comprising saturating a porous. inert diatomaceous carrier material with a strong aqueous solution of phosphoric acid, heating the resulting impregnated carrier material in can atmosphere containing water vapour having a partial pressure which is less than the partial -pressure of water vapour in equilibrium with an aqueous solution of phosphoric acid at the temperature at which the heating is effected, digesting the heated carrier material with acidified - hot water having a pH less than about 1, washing the digested carrier material with hot water, drying the washed -carrier material and impregnating the dried carrier material with an aqueous solution of phosphoric acid. 2. A process as claimed in claim 1, wherein said carrier- material is saturated in said first impregnation stage with an aqueous solution of phosphoric acid having a concentration of at least 70% by weight. 3. A process as claimed in claim 1 or claim 2, wherein said - impregnated carrier material obtained in said - first impregnation stage is heated in the water vapour-containing atmosphere at a temperature - between about 225 C and about 325 C. 4. A process as claimed in any one of the preceding daims, wherein said impregnated carrier material obtained in said first impregnation stage is heated in an atmosphere containing- water vapour at a partial pressure between about 150 and 300 millimetres of mercury. 5. A process as claimed in any one of the preceding claims. wherein the aqueous phosphoric acid with which said washed and dried carrier is impregnated has a concentration of between 55 and 65''o by weight of H3POo, and said acid is thereafter concentrated iZ2 sit on said carrier to a concentration above 70% by weight of H3PO. 6. A process for the production of a composite catalyst substantially as described hereinbefore with reference to Example I. 7. A composite catalyst when prepared by a process as claimed in any of the preceding claims wherein the carrier material has an average pore radius of between about 3500 A and about 6500 , at least 5% of the pores having a radius of less than about 5QO A 8. A catalyst as claimed in claim 7, comprising a granular carrier material impregnated with an aqueous solution of phosphoric acid containing between- 75,u and 95''u bp weight of H3 P.O4. 9. A composite catalyst when prepared by the process claimed in any one of claims 1-6. 40, A process for the preparation of an alcohol by direct hydration of an olefin, which comprises contacting a gaseous mixture of an olefin and water at elevated temperature and pressure with a composite

catalyst as claimed in any one of claims 7 to 9, the temperature, pressure and molecular ratio; of the reactants being controlled so that the aqueous solution of phosphoric acid supported on the carrier has a concentration of at least 70% by weight. 11. A process as claimed in claim 10, wherein. the catalyst is maintained at a temperature between 265 and 300 C. 12. A process as claimed in claim 10 or claim 11, wherein small amounts of phosphoric acid are added to the support during the process to maintain the catalyst activity level. 13. A process as claimed in any one of claims 10-12, wherein the olefin is ethylene. 14. A process for the preparation of an alcohol by direct hydration of an olefin as claimed in any one of claims 10-13 substantially as described hereinbefore with refer

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