5586 5590.output

* GB785994 (A)

Description: GB785994 (A) ? 1957-11-06

Improved fluid coking process

Description of GB785994 (A)

PATENT SPECIFICATION 7,

Datet of Application andfiling Complete Specietiatfion:

July 22, 1955 No 21320155.

Application made in United States of America on Aug 23, 1954.

(Patent of Addition to No, 752,400, dated May 20, 1954).

Complete Specification P'ubiihed: Nov 6, 1957.

Index at Acceptance:-Classes 32, E 2; and 55 ( 1), AK( 1: 2: 6 A: 6

B).

International Classification:-l Ob, g.

COMPLETE SPECIFICATION.

Improved Fluid Coking Process.

We, Esso RESEARCH AND ENGINEERING Comp ANY, a corporation duly

organized and existing under the laws of the State of Delaware, United

States of America, having an office at Elizabeth, New Jersey, 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:

This invention relates to a process for converting hydrocarbons, and

more particularly to coking of heavy residual oils by the fluidized

solids technique Specifically, this invention is concerned with an

improved hydrocarbon oil fluid coking process wherein a coking charge

stock is contacted at a coking temperature with a body of coke

particles maintained in a fluidized state in a coking zone.

Fluid coking processes in which an oil is pyrolytically upgraded by

contact at a coking temperature with particulate solids maintained in

a fluidized state in a coking vessel are well known Upon contact with

the solids, the oil undergoes pyrolysis, evolving lighter hydrocarbons

and depositing carbonaceous residue on the solid particles causing

them to grow in size The necessary heat for the pyrolysis is supplied

by circulating a stream of the fluidized solids through an external

heating zone e g, a combustion zone, and back to the coking vessel.

Because more coke is produced by the coking process than is required

to be burnt to supply heat, the heat-carrying solids will continue to

grow in size because of the carbon deposition and a portion of the

solids must be withdrawn to maintain the total mass or weight

inventory of the particles substantially constant It is customary in

commercial processes to withdraw some of the coke from the system,

comminute the lPrice 3 s 6 d l coke in some manner to form seed coke

or growth nuclei and to return the seed coke to the process to

maintain the particle size and particle size distribution relatively

constant.

This size reduction of solids may be accomplished, for example, by jet

attrition grinding.

The net coke product of the process may be classified as by

elutriation such that only relatively coarse material is withdrawn

whereby the coke of seed size in the process is conserved.

Serious problems have been encountered in the development of this type

of coking.

One problem in particular is the building up of coke deposits on the

confines of the vapor space above the fluidized bed These deposits

cause the pressure drop through the coker and overhead lines to

increase to such an extent as to require the coker to be shut down

periodically and cleaned out.

As the vapors leaving the coking bed are at or near their dew-point,

(i e, their condensation-point), they will readily condense.

This condensation is aided by endothermic polymerization and

condensation reactions occurring in the vapor phase It has been found

that if this condensation of the coker vapors is on surfaces having a

temperature of about 700 to 1000 F, severe coke deposition occurs.

It had not been appreciated heretobefore that entrained solids from

the coking bed, if present above a critical level in the coker product

vapors, prevent coke deposition and fouling in the overhead system of

the coking reactor The present invention is based on the discovery

that by proper control of the operating conditions of a coking

process, partly by control of the particle size, particlesize

distribution and fluidization gas velocities, solid particle

entrainment rates from the fluid bed can be controlled, and by

controlling the entrainment rate and holding it 85,994 so 4 S rd

785,994 above a certain critical minimum, coke deposition is

substantially eliminated.

Specifically, it has now been found that coke deposition on the

interior surfaces of the coking vessel above the fluid bed can be

greatly inhibited or substantially eliminated by maintaining, in the

vapors in the part of the vessel above the fluidized bed, entrained

solids from the fluid coking bed in amounts above a certain critical

minimum, specifically, above 400 lbs /bbl of coking charge stock.

Entrained solids in amounts above this critical level help to uphold

the temperature of the vapors and scour attendant surfaces, thereby

removing carbon deposits and providing surfaces upon which condensing

vapors are absorbed.

According to the present invention, there is provided a hydrocarbon

oil conversion process of the type in which a coking chargestock is

contacted with particulate solids maintained at a coking temperature

as a dense fluidized bed in a coking vessel to obtain relatively

lighter hydrocarbon vapors in the part of the vessel above the

fluidized bed from the upper surface of the bed and thence from the

coking vessel; characterized in that there is'maintained in the said

hydrocarbon vapors an entrainment of the solids 3 i 5 of above 400 lbs

Ibbl of the charge stock.

The hydrocarbon oil which forms the coking charge stock of the present

process is preferably a low value high-boiling residuum of about -10

to 200 A Pl gravity, about 5 33 to 50 wt % Conradson carbon, and

boiling above about 9000 to 12000 F Broadly, however, any hydrocarbon

oil may be treated in the present process, including shale oils, tars,

asphalts, oils derived from coals, synthetic oils, recycled heavy ends

from the coker effluent, whole crudes, heavy distillate and residual

fractions therefrom, or mixtures thereof.

The nature of the present invention will more clearly appear during

the following description of the drawings attached to and forming a

part of this Specification In the drawings, Figure 1 schematically

presents a preferred hydrocarbon oil fluid coking process adapted to

achieve the objects of this invention Figures 2, 3 and 4 are graphical

presentations of data illustrating this invention and its advantages.

Referring to Figure 1, the major items of equipment shown are a coking

vessel 1 and a combustion vessel or burner 2 used to supply heat to

the process The fluid coker 1 contains a fluidized bed of high

temperature solids having an upper level L Preferably, the solids used

in the coking process are finely divided coke particles produced by

the process Other solids such as sand, spent catalyst, or pumice, may

however, be used In this particular coking vessel design, the lower

portion 1-A of the vessel serves as a stripping zone The intermediate

portion, 1-B, is conical in shape so as to minimize the consumption of

fluidizing gas by permitting conversion products generated in the

lower portion of the coker to serve as fluidizing 70 gas in the upper

portions The upper portion 1-C is made narrower so as to increase the

velocity of the vapors withdrawn overhead thereby decreasing secondary

vapor phase cracking of the products As 75 will later appear, the

extent of reduction in the cross-sectional area of the coker at this

point is an important design consideration, as the velocities of the

vapors affect the solid entrainment rate 80 The oil to be upgraded,

such as a vacuum residuum, is injected into the vessel at a plurality

of points via line 3 The feed rate is preferably maintained at a rate

between to 150 bblldy/ft 2 of reactor cross 85 section area at the

upper level of the bed.

The oil undergoes pyrolysis at a temperature in the range of 850 ' to

16000 F, preferably 950 to 10500 F When gas oils for catalytic

cracking are desired, the coker is operated 90 at a temperature in the

range of 9500 to 10500 F When lighter products are desired, e.g,

naphthas and heating oils, the operating temperature is about 1050 to

1200 ' F and when chemicals and chemical intermediates A)5 are

desired, the temperature is 1200 ' to 16000 F, preferably 1300 ' to

1450 ̂F.

Steam is admitted to the base of the vessel as by line 4 This steam

serves first to strip the coke particles before the coke is circulated

11)0 to the burner and then passes upwardly through the vessel

fluidizing the solids therein The reaction products are taken off

overhead by line 5 after having entrained solids removed by cyclone 6

and may be 105 further processed, as desired.

In order to supply heat to the process, solids are circulated from the

base of the coking vessel by line 7 to a burner vessel 2.

Here the particles are fluidized by an oxi 110 dizing gas, e g, air,

supplied by line 8 The resulting combustion heats the particles to a

temperature 1000 to 3000 F higher than the coking temperature After

having entrained solids removed, flue gases are removed 115 overhead

from the burner vessel by line 9 and may be vented to the atmosphere.

Heated solids are transferred to the fluid coker by line 10 Other

means may, of course, be used to reheat the coke particles 120

including gravitating bed burners, transfer line burners, shot heating

systems, and other direct and indirect heating means Line 11 removes

from the coking vessel the net coke product and agglomerates produced

by the 125 process.

Coking deposits will normally form in the coking vessel on the

surfaces above the fluid bed level L including the surfaces of cyclone

6 and overhead line 5 unless steps are taken 130 have to be operated

at capacities less than maximum A preferred method of controlling the

superficial gas velocity is to control the level L of the fluid bed

along a tapered portion of the reactor as shown 70 By increasing the

amount of coke hold-up in the reactor, the level L will move upwardly

along this tapered portion and consequently the cross-sectional area

of the surfaces of the fluid bed will be decreased 75 Thus the

fluidizing gas velocity through this surface will be increased and the

entrainment rate will thereby be increased The extent of this taper

is, of course, a design consideration and can be made to provide for a

80 fairly wide range of operating conditions.

By proper design, the reactor may be configured to achieve an

entrainment rate of over 4-00 lbs of coke /bbl of feed without the

necessity of resorting to any special control 85 techniques.

So far as it is known, it is believed that the entrainment from a

fluid bed with a given particle size and superficial gas velocity and

the amount of solids entrained in withdrawn 90 vapors is substantially

independent of the reactor geometry or configuration at the top or

above the fluid bed with the exception of reactor outage Outage is the

distance from the surface of the fluid bed to the cyclone 95 outlet,

indicated by the dimension 0 on the drawing As the outage is

increased, the amount of solids contained in the vapors in the

uppermost portions of the reactor will be decreased 109) Figure 3

shows in simplified relations a method of controlling the entrainment

rate.

Although the coke particle size used in fluid coking may vary up to

1000 microns or more, the preferred particle size is within the range

105 of 40-500 microns, with 200-300 microns being the median particle

size The particle distribution may vary within these ranges.

The preferred particle distribution is such that 10 to 20 wt % of the

coke is smaller 110 than 147 microns, 30 to 60 wt % is smaller than

175 microns, 60 to 90 wt % is smaller than 246 microns and O to 5 wt %

is no larger than 400 microns This particle size and distribution are

controlled by controlling 115 the rate and size of seed coke additions

and coke product withdrawal The coke particles normally have a true

particle density in the range of 90 to 110 lbs /ft 3 For material this

size, the superficial gas veloci 120 ties in the reactor will lie in

the range of 1-5 ft /sec and bed densities will be in the range of 30

to 55 lbs Ift 3.

For a fluid coking vessel operating under normal coking conditions, e

g, temperature 125 9500 F, pressure 6 ' psig, fluidizing steam wt %

based on feed, coke circulation rate to burner 15 lbs /lb of feed, a

chart in the nature of Figure 3 may be prepared Figure 3 relates feed

rate in bbls /day /sq ft of cross 133 to prevent their formation This

invention is directed primarily towards tile prevention of coking

between the fluid bed level L and the inlet C, to the cyclone,

although operation in accordance with the present invention will

substantially reduce coking of the equipment beyond inlet C It is in

this area between L and C where the greatest amount of coke deposition

occurs in normal coking operations.

In some coking processes, the solid-; separating means, i e, cyclone,

is located outside the coking reactor The present invention is also

applicable to such designs.

According to the present invention, the superficial velocity of the

vapors, which comprises reaction products and fluidizing gas, through

the upper surfaces L of the fluid bed is regulated to obtain an

entrainment above 400 lbs /bbl of stock charged to the coker By

maintaining this entrainment rate, coking of the equipment is

substantially prevented.

The criticality of maintaining a certain 2.5 entrainment rate will be

appreciated by reference to Figure 2, which presents data obtained

from a fluid cokier operating under conventional conditions The

abscissa of Figure 2 indicates the increase in pressure drop from the

level L of the fluid bed through the cyclone outlet due to coking and

fouling in a coking vessel, as related to the amount of solids

entrained in the vapors withdrawn overhead As can readily be seen,

coking of equipment is virtually nonexistent when the entrainment rate

is above 400 lbs Ibbl.

of feed When the entrainment rate is less than 400 lbs Ibbl, then the

increase in pressure drop due to coking increases almost exponentially

with decreases in entrainment rate The figure also shows that there is

no practical advantage obtained by maintaining the entrainment rate

above 800 lbs of solids Ibbl of feed.

The entrainment rate of solids from the fluid bed is controlled

primarily by control of the superficial fluidized gas velocity.

Attention must be paid, however, to the particle size and size

distribution of the ao fluidized coke For a relatively coarse

material, fluidizing gas velocity will have to be higher to obtain a

given entrainment as opposed to the use of a finer material.

The fluidizing gas velocity may be controlled by various methods The

amount of fluidizing steam or other inert gases used may, of course,

be controlled to regulate the superficial gas velocity Excessive use

of fluidizing gas is to be avoided, however, as it results in

uneconomical operation The rate of feed injection into the coking

vessel may also be controlled so as to control fluidizing gas velocity

This method of control per se is not too attractive as it may mean in

some instances that the coker will 785,994 sectional area of the

reactor to the entrainment rate in lbs /bbl of feed which is dependent

upon the superficial gas velocity and size distribution of the coke in

the figure Wt %, retained on 80 mesh is used in the chart as being

indicative of the size distribution of the coke Thus, for a set of

conditions, the fluidizing gas velocity necessary to obtain the

minimum entrainment needed to avoid colke deposition can be obtained

from Figure 3 following lines X Y and Z in the direction indicated.

A commercial fluid coker majy be designed to provide sufficient gas

velocity in the top of the reactor to give sufficient entrainment

under normal conditions It is quite possible, however, that a coking

unit may be called upon to operate at widely varying feed rates For

example, the unit may process 10,000 B /D of oil in the winter and yet

only be required to handle 4000 B ID in the summer At the lower feed

rate, the gas velocity in the top of the reactor will be greatly

reduced This would mean that unless special operating controls were

invoked, the entrainment rate would become dangerously low, leading to

coke deposits in the top of the reactor followed by a shut down of the

unit By use of a plot similar to Figure 3, however, proper entrainment

can be maintained As the feed rate is reduced, both the velocity and

the particle size of the circulating coke can be varied to hold the

entrainment above 400 lbs Ibbl of feed Velocity can be adjusted by

increasing the quantity of fluidizing gas and by controlling the

position of the surface of the fluid bed with respect to upper tapered

portion of the reactor, if the reactor be so designed The particle

size and distribution can be varied by adjusting the amount and size

of seed coke or growth nuclei added to the system.

For example, with reference to Figure 3, a coking reactor may normally

handle an B /D Ift 2 of reactor cross-section, of feed.

The entrainment at this rate may be desired to be about 600 lbs Ibbl

of feed The lines X'., Y 1 and Z 1 on Figure 3 represent the

conditions necessary to maintain the desired entrainment If the feed

rate becomes Bl D Ift 2, then the entrainment will drop below the

minimum for safe operation, even though this decrease is partially

compensated for by a decrease in particle size, as indicated by lines

X, Yll and Z 11 But by a change both in gas velocity and in particle

size, as indicated by lines X, Y and Z, the entrainment can be brought

back to the desired 600 lbs /bbl.

Figure -3 was based upon a coking vessel having about 11 ft outage

Figure 4 illustrates a method that may be used to extrapolate the data

of Figure 3 to a coking vessel having a different " outage ' The

abscissa of Figure 4 indicates the outane in feed and the ordinate

Yields a multiplies which can be used to adjust the curves in the left

field of Figure 2 upwardly or downwardly.

It should be understood that the Figures 3 74 and 4 havle been used

only to illustrate one method of controlling and determining the

entrainment rate and this invention is not to be limited thereby Other

methods may wvell be used It is important however, that 7 athe

entrainment in the vapors withdrawn overhead be above 400 lbs /bbl of

feed.

Solids entrained according to this invention are most beneficial in

preventing coke deposits before the cyclone inlet However a coke

deposition in the cyclone and beyond is also inhibited because the

high entrainment minimizes temperature drop and, therefore.

inhibits condensation of the vapors The solids also absorb any

condensate and poly 85 meric material formed from the vapors The

entrained solids will also provide a scouring action in the cyclone

and, due to some coke losses through the cyclone, will scour the lines

after the cyclone 90

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* GB785995 (A)

Description: GB785995 (A) ? 1957-11-06

Improvements in or relating to the preparation of titanium carbide, boride

or nitride


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particular, the EPO does not guarantee that they are complete,

up-to-date or fit for specific purposes.

r

PATENT SPECIFICATION

785,995 Date of Application and filing Complete Specification: Aug 11,

1955.

No 23229/55.


Complete Specification Published: Nov 6, i 957.

Pam 78 >.Cv Ii ICXT OJ, NO 73 'D, 98 Re erence as been -e A Pursu oeh

Pae A Ct, 1949 t Oe Pearrednt 2 c 'T d 77-j 11;S 2 r a Th: PAT 2 INT O

FF 10, igth Yl:zrch, 19 D L' O 5446/1 ( 4)/a D 8 g 150 //ES for making

titanium and more especially to an improvement in the method of

forming a starting composition from which said titanium compounds may

be formed.

An object of the present invention is to provide an improved method

for forming a homogeneous mixture of titanium hydrate, titanium

phosphate or alkali altered titanium hydrate and carbon particles for

use in the preparation of said titanium compounds.

The invention provides a starting composition for the preparation of

titanium carbide, boride or nitride comprising an intimate mixture of

titanium hydrate, titanium phosphate or alkali altered titanium

hydrate and carbon particles prepared by precipitating the titanium

hydrate, titanium phosphate or alkali altered titanium hydrate from

aqueous solution in the presence of the carbon particles so that the

titanium hydrate, hydrated titanium phosphate or alkali altered

titanium hydrate and carbon particles are joined by a coalescent bond.

The titanium hydrate is an uncalcined hydrate precipitated usually by

hydrolysis from a salt solution prepared from an acid digest of a

titaniferous material, such as, for example, titaniferous ore, ore

concentrates or slags By way of illustration, the digestion treatment

may comprise mixing a titaniferous material with concentrated ( 93 '

sv/w v) sulphuric acid in an amount such that the ratio of acid,

calculated as 100 % sulphuric acid, to the titaniferous material, on a

Ti O, basis, is precipltateu uv washed.

Although washing serves to remove large amounts of soluble salts and

free acid there is usually some acid present in the form of a basic

salt or adsorbed acid which may impair the quality of the titanium

compounds to be formed therefrom, and hence the hydrate may be treated

with a basic substance, such as alkaline compounds of sodium,

potassium or ammonium to neutralize and/or remove the adsorbed acid In

general, the size of the individual particles, that is to say the

crystalloids or agglomerates of crystalloids of precipitated hydrous

titanium oxide, is within the range of from about 0 01 to 0 5 microns.

For reasons of economy, sulphuric acid solutions of titanium are used

in carrying out the process of the present invention in preference to

solutions prepared from hydrochloric acid.

To prepare the starting composition of this invention using an

unaltered titanium hydrate pulp, finely divided carbon having a

particle size in the range of from 0 005 to 0 01 microns and

preferably hydrophilic, may be added to a titanium sulphate solution

prepared in the manner hereinabove described, prior to hydrolysis,

whereupon the mixture is heated and maintained at a temperature within

the range of about 1000 C to 1120 C for approximately two hours

whereby most of the titanium oxide values in the solution is

hydrolyzed and precipitated out as hydrous Ind Int 8 () t k 11, 1 1 1

1, -"'11 -9 AI 9 A 1)PATENT SPECIFICATION

785 995 Date of Application and filing Complete Specification: Aug I

1, 1955.

No 23229155.


Complete Specification Published: Nov 6, 1957.

idex at acceptance:-Class 1 ( 2), E( 1 A 1: 2 A 1: 5 A 1).

iternational Classification:-C Olb.

COMPLETE SPECIFICATION

Improvements in or relating to the preparation of Titanium Carbide,

Boride or Nitride We, NATIONAL LEAD COMPANY, a Corporation organised

and existing under the Laws of the State of New Jersey, United States

of America, of 111, Broadway, New York 6, State of 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: -

The present invention relates to a process for making titanium

carbide, boride or nitride and more especially to an improvement in

the method of forming a starting composition from which said titanium

compounds may be formed.

An object of the present invention is to provide an improved method

for forming a homogeneous mixture of titanium hydrate, titanium

phosphate or alkali altered titanium hydrate and carbon particles for

use in the preparation of said titanium compounds.

The invention provides a starting composition for the preparation of

titanium carbide, boride or nitride comprising an intimate mixture of

titanium hydrate, titanium phosphate or alkali altered titanium

hydrate and carbon particles prepared by precipitating the titanium

hydrate, titanium phosphate or alkali altered titanium hydrate from

aqueous solution in the presence of the carbon particles so that the

titanium hydrate, hydrated titanium phosphate or alkali altered

titanium hydrate and carbon particles are joined by a coalescent bond.

The titanium hydrate is an uncalcined hydrate precipitated usually by

hydrolysis from a salt solution prepared from an acid digest of a

titaniferous material, such as, for example, titaniferous ore, ore

concentrates or slags By way of illustration, the digestion treatment

may comprise mixing a titaniferous material with concentrated ( 93 %

w/w) sulphuric acid in an amount such that the ratio of acid,

calculated as 100 % sulphuric acid, to the titaniferous material, on a

Ti OQ basis, is within the range of from about 1 3 to 1 5 parts acid

to one part titaniferous material, and heating the mixture until a

reaction sets in and a digestion cake is formed The digestion cake is

then dissolved in water to form a solution to which scrap iron or the

like is added to convert the ferric iron values to ferrous iron The

solution is then clarified, filtered, concentrated and crystallized in

the manner well-known to the art of pigment manufacture to form a

titanium sulphate solution from which the hydrous titanium oxide is

precipitated by hydrolysis and thereafter washed.

Although washing serves to remove large amounts of soluble salts and

free acid, there is usually some acid present in the form of a basic

salt or adsorbed acid which may impair the quality of the titanium

compounds to be formed therefrom, and hence the hydrate may be treated

with a basic substance, such as alkaline compounds of sodium,

potassium or ammonium to neutralize and/or remove the adsorbed acid In

general, the size of the individual particles, that is to say the

crystalloids or agglomerates of crystalloids of precipitated hydrous

titanium oxide, is within the range of from about 0 01 to 0 5 microns.

For reasons of economy, sulphuric acid solutions of titanium are used

in carrying out the process of the present invention in preference to

solutions prepared from hydrochloric acid.

To prepare the starting composition of this invention using an

unaltered titanium hydrate pulp, finely divided carbon having a

particle size in the range of from 0 005 to 0 01 microns and

preferably hydrophilic, may be added to a titanium sulphate solution

prepared in the manner hereinabove described, prior to hydrolysis,

whereupon the mixture is heated and maintained at a temperature within

the range of about 1000 C to 1120 C for approximately two hours

whereby most of the titanium oxide values in the solution is

hydrolyzed and precipitated out as hydrous .f I_ titanium oxide in the

presence of the individual carbon particles Thereby, the individual

particles of hydrous titanium oxide are joined with the individual

carbon particles by a coalescent bond to form a uniform intimate

mixture of the hydrate and carbon.

This mixture is then filtered or otherwise separated from the soluble

salts and acid formed during the hydrolysis, washed and subsequently

dried to provide a starting composition from which titanium carbide,

boride or nitride may be formed as described below, the size of the

particles of the starting composition being for example within the

range of from 0 02 to 0 5 microns.

While the procedure described above is satisfactory, improved yields

of the hydrate may be obtained by the expedient of adding a nucleating

agent to the salt solution at hydrolysis A typical nucleating agent,

sometimes referred to in the art as a yield seed, is that prepared

from a titanium sulphate hydrolysate by treatment of the latter with

an alkali metal hydroxide, such as sodium hydroxide, to form an alkali

altered hydrate.

The thermal hydrolysis of a titanium salt solution, as hereinabove

described, produces a hydrate in the form of metatitanic acid, but it

is within the scope of the invention to form the hydrate as

ortho-titanic acid.

Although a titanium hydrate formed from a titanium sulphate solution,

as hereinabove described is highly satisfactory, hydrated titanium

phosphate or alkali altered titanium hydrate may be used instead Thus,

it is within the scope of the invention to prepare a starting

composition by mixing a dilute aqueous solution of phosphoric acid or

a phosphate and a dilute aqueous titanium salt solution at room

temperature in the presence of finely divided carbon, and then heating

the mixture to complete the reaction and form a filterable starting

compound comprising individual particles of titanium phosphate joined

to the individual carbon particles by a coalescent bond; or by adding

phosphoric acid or a soluble phosphate to the unmodified starting

compositions hereinabove described, thereby to convert the hydrous

titanium oxide component to titanium phosphate in the presence of the

carbon.

It has been found also that the starting composition of this invention

may be formed from a mixture of an alkali altered hydrate and finely

divided carbon particles As used herein, the phrase "alkali altered

hydrate" denotes a material which according to one method is prepared

from an unaltered hydrate, as hereinabove described, by adding thereto

an alkali metal hydroxide, e g, sodium hydroxide, in much the same way

that an alkali metal hydroxide is added to the hydrate to neutralize

the sulphate values, except that in this instance sufficient alkali

metal hydroxide is added not 6 only: to neutralize the sulphate values

but to alter the hydrate itself such that upon calcination it will be

converted to a sodium titanate or mixture of sodium titanates It has

been found that a suitable amount of sodium hydroxide would be

approximately 1 l parts by weight to 1 part by weight of Ti O, As an

alternative method for preparing the alkali altered hydrate, the

latter may be formed in the presence of finely divided carbon, from a

pure titanium salt solution, i e, one which is free of iron and other

impurities by addition of sufficient alkali to the solution to

neutralize all the acid and for the alteration of the hydrate.

A feature which is common to each of the above described starting

compositions is the step by which intimate contact is achieved between

the particles of the hydrated titanium compound and the carbon

particles, in each instance the titanium compound being intimately

joined with the individual carbon particles by formation of the

compound in the presence of the carbon particles.

While the formation of the starting material of this invention by

thermal hydrolysis of a sulphate solution in the presence of carbon

may be carried out successfully at atmospheric pressure, it has been

found that the rate of hydrolysis may be accelerated considerably by

carrying out the operation in an autoclave under pressures of 100 to

500 lbs per square inch Pressure hydrolysis, preferably coupled with

agitation, results in a thorough blending of the titanium compound and

carbon particles in a relatively short time.

The following is a description by way of example of methods of

carrying the invention into effect.

c EXAMPLE I.

To prepare the unmodified starting com 1 ( position of this invention,

a clarified sulphate solution is prepared in a manner well-known in

the art, as for example by digesting a titaniferous ore in

concentrated H 25 04 to form a digest cake which is dissolved in H O,

1 l filtered, clarified, crystallized, and again diluted with H 2 O to

form a solution having a Ti O 2 content of about 200 grams per litre.

To this solution was added finely divided hydrophilic carbon in an

amount which was 11 varied depending upon the titanium compound to be

formed therefrom Thus, when the solution was to be used to prepare

titanium carbide, finely divided hydrophilic carbon was added to the

solution in an amount to satisfy 12 the formula:

Ti O, + 3 C-Ti C + 2 C O based on the amount of titanium, calculated

as Ti O,, recovered from the solution.

A solution prepared in the above manner 12 was boiled for about two

hours in the presence of 1 % yield seed until about 95 % of the

titanium was precipitated out as a titanium 785,995 tion of phosphoric

acid ( 50 grams per litre P 1,0) was added to a titanium sulphate

solution ( 30 grams per litre Ti O,) containing finely divided carbon,

the weight ratio of PO, to the titanium values being 0 6 on a Ti O 2

basis The carbon was present in an amount to satisfy the formula:

Ti P,07 + 8 C= Ti C+ 7 CO + P 2 hydrate intimately associated with the

fine particles of carbon This starting composition was then separated

from the liquid, washed and dried, and subsequently converted to

titanium carbide by calcination.

To this end the starting composition was placed in a furnace and

calcined at a temperature of about 16500 C for about two hours in an

inert atmosphere The resulting product comprised a finely divided

powder, the size of the particles being from 1 to 10 microns An

analysis of the product showed 80.% titanium and 19 5 % carbon.

EXAMPLE II.

To prepare titanium boride starting composition was prepared

substantially in the manner described in Example I except that in this

instance finely divided hydrophilic carbon was added to the sulphate

solution prior to hydrolysis in an amount to satisfy the formula:

Ti Oai + B,0, + 5 G-+Ti B, + 5 C O based on the amount of titanium,

calculated as Ti O, recovered from the solution.

To prepare titanium boride from the resulting starting composition,

130 parts, on a weight basis, of boric acid, as B 0,, were added for

every 148 parts of Ti O 2 in the starting composition, and the mixture

was agitated for a sufficient length of time to thoroughly disseminate

the boric acid therethrough whereupon the mixture was introduced into

a furnace and calcined at a temperature of about 1550 C for about two

hours in an atmosphere of argon.

The resulting product comprised a finely divided powder which analyzed

68 4 % titanium and 29 6 % boron and had an effective particle size of

from 1 to 5 microns.

EXAMPLE III.

To prepare titanium nitride, a starting composition was formed by the

method described in Example I except that in this instance finely

divided hydrophilic carbon was added to the sulphate solution in an

amount to satisfy the formula:

Ti Q, + 2 C+ N->Ti N+ 2 C O based on the amount of titanium,

calculated as Ti O,, recovered from the solution The starting

composition resulting from hydrolysis of this solution was dried and

introduced into a furnace and calcined at a temperature of about 1350

C for about two hours in an atmosphere of nitrogen The resulting

product comprised a finely divided titanium nitride powder which

analyzed 78 6 % titanium and 19.4 % nitrogen, the size of the

particles being from 1 to 15 microns.

EXAMPLE IV.

To prepare titanium carbide from a starting composition comprising

titanium phosphate and hydrophilic carbon, a dilute solubased on the

titanium, calculated as Ti P,01, recovered from the solution This

mixture was heated for one hour at a temperature of about C and

precipitated a starting composition of coalesced titanium phosphate

and carbon which, after being dried, was introduced into a furnace and

calcined at a temperature of about 16000 C for about two hours in an

atmosphere of argon.

The resulting product comprised a finely divided titanium carbide

powder which analyzed 79 1 % titanium and 19 3 % carbon, the particle

size of the product being in the range of from 1 to 10 microns.

EXAMPLE V.

To prepare titanium nitride from a starting composition of coalesced

titanium phosphate and hydrophilic carbon, a starting composition was

prepared substantially in the manner described in Example IV except

that finely divided carbon was added in an amount to satisfy the

formula:

N, Ti P,07 + 7 C Ti N + 7 C O + P.

based on the amount of titanium, calculated as Ti P 50,, recovered

from the solution This starting composition was calcined at a tem 95

perature of about 13500 C for two hours in an atmosphere of nitrogen

The resulting product was a finely divided titanium nitride powder of

substantially uniform particle size, which analyzed 79 % titanium and

21 % 100 nitrogen, the particles ranging in size from about 1 to 10

microns.

EXAMPLE VI.

To form titanium boride a starting composition of titanium phosphate

and hydro 105 philic carbon was prepared as described in Example IV

except that finely divided carbon was added in an amount to satisfy

the formula:

Ti P,0,9 + l OC + B,Q, = Ti B,,,+ l OCO + P 1, based on the amount of

titanium, calculated 110 as Ti O 2, recovered from the solution For

every 148 parts of titanium, calculated as Ti O 2, in the

titanium-phosphate-carbon composition were added 130 parts boric acid

as BO, The mixture was thoroughly agitated for a sufficient 115 length

of time to form intimate contact of the materials whereupon the

mixture was introduced into a furnace and calcined at a temperature of

about 15500 C for about two.

W 8,9 g 5 hours in an atmosphere of argon.

The resulting product comprised finely divided powder which analyzed

68 1 % titanium and 299 % boron, the effective particle size being

from 1 to 5 microns.

As mentioned above, the invention also contemplates the preparation of

a starting composition comprising a mixture of an alkali altered

hydrate and carbon from which the carbide, nitride and boride

metalloids may be produced in the manner described above.

One way in which this alkali altered hydrate-carbon starting

composition may be prepared is by thermal hydrolysis of a sulphate

solution and carbon, in situ, as described in Example I, and then

adding to the resulting hydrate-carbon mixture a quantity of an alkali

metal hydroxide, for example, sodium hydroxide.

The alkali altered hydrate-carbon starting composition may also be

prepared from a pure titanium salt solution, that is to say a solution

free of iron, vanadium, aluminium and other impurities By way of

example, finely divided carbon may be added to a pure chloride

solution, such as titanium tetrachloride, and to this mixture is added

an alkali metal, such as sodium hydroxide, in an amount sufficient

both to neutralize the solution and alter the hydrate The resulting

hydrolysate will comprise an admixture of carbon particles, bonded

with the particles of alkali altered hydrate from which the soluble

salts may be removed by washing prior to calcination.

From the foregoing description and examples it will be evident that

the starting composition of the present invention is a highly reactive

material which may be calcined at relatively low temperatures to form

titanium carbide, boride or nitride of high purity and uniform and

fine particle size.

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* GB785996 (A)

Description: GB785996 (A) ? 1957-11-06

Improvements in and apparatus for injection moulding polymers of halogen-

containing vinyl compounds


COMPLETE SPECIFICATION.

Improvements in and Apparatus for Injection Moulding Polymers of

Halogen- Containing Vinyl Compounds.

We, CHEMISOHE WERKE HULS AXTIEN- GE5ELL5OHAFT, a German Body

Corporate, of 21A Marl, ltreis Becklinghausen, 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

It has already been proposed to work up polymers of halogen-containing

vinyl compounds by injection moulding or extrusion pressing by heating

the polymer in an injection-moulding-cyli.nder of an

injection-moulding machine to the temperature necessary for a

satisfactory flow and then extruding it through a nozzle under

pressure into the mould. Hitherto, however, only polymers containing

softeners could be worked up without difficulty because in the case of

polymers free from softener the temperature necessary for a

satisfactory flow is dangerously near to the decomposition

temperature. Therefore when polymers free from softener are wolked up

for injectionmoulding by known methods, account must be taken of

decomposition phenomena, in particular with the formation of hydrogen

chloride, and this on the one hand impairs the value of the injection

moulding and on the other hand endangers the injectionmoulding

apparatus used. The decomposition phenomena can be suppressed by the

addition of considerable amounts of stabilisers but not excluded. If

the temperature necessary for satisfactory flow of the polymer is

reduced by the addition of lubricants, the mechanical values of the

products obtained are worsened.

We have now found that polymers of halogen-containing vinyl compounds

which are free from softener can be injectionmoulded in an

advantageous way by heating the polymer in the

injection-mouldingcylinder to a temperature which is 10 to 20 C. below

the temperature which is necessary for satisfactory flow and producing

the temperature necessary for satisfactory flow by pressing out the

polymer into the mould through a constriction under high pressure. As

a polymer of a halogen-containing vinyl compound, polyvinyl chloride

is especially suitable which can be prepared by emulsion

polymerisation or by suspension polymerisation, and other suitable

compounds are after-chlorinated polyvinyl chloride, polyvinylidene

chloride and copolymers of vinyl chloride and vinylidene chloride with

each other or with other polymerisable compounds. The usual additions

of fillers, dyestuffs, stabilisers and lubricants may be incorporated

with the polymers. Stabilisers are only necessary in amounts smaller

than in the known methods, as for example 0.5 to 3%, or less active

stabilisers, as for example non-toxic stabilisers, can be used the

introduction of which for the injection moulding of polymers free from

softener according to the known methods is impossible.

If desired the addition of lubricants can be entirely dispensed with.

The temperature necessary for satisfactory flow and lying in the

neighbourhood of the decomposition temperature is preferably

ascertained by a preliminary experiment.

The polymer is then heated in the injectionmoulding- cylinder of an

injection-moulding machine, while avoiding overheating, to

temperatures which are 10 to 200 C. below the temperature necessary

for satisfactory flow. This heating is preferably effected in zones,

for example by resistance heating coils wound around the

injection-moulding.

cylinder. For forcing out the heated polymer into the mould through a

constriction, a pressure of more than 1500 kilograms per square

centimetre is required.

The constriction should amount to at least 50% calculated as reduction

in cross-section as compared with the original cross-section.

The length of the constriction should amount to at least half of the

diameter of the original cross-section. If the constriction is slight,

its length must be great. If the constriction is considerable, it is

sufficient for it to have a short length. Since the pressure necessary

for forcing out the polymer increases as the constriction increases,

the constriction has an upper limit placed thereon by the pressure

economically produceable in the apparatus used. The lower limit of the

constriction is provided by the fact that with decreasing constriction

the necessary length soon becomes cumbersome and uneconomical. It is

advantageous to use constrictions of 75 to 95% which have a length

about equal to 4 to 2 times the diameter of the original cposs-

section. From the constriction a stream of polymer is then led in

known manner into the mould which is advantageously preheated to a

temperature of 400 to 600 C.

By working in this way, the polymer is only exposed to the temperature

necessary for a satisfactory flow for a short time, namely from its

passage through the constriction to its entry into the injection

mould. In this way a decomposition and consequent injury to the

polymer and- the apparatus are avoided. It is even possible in this

way to work up polymers of which the temperature necessary for

satisfactory flow coincides with the decomposition temperature.

We have also found that the said process can be carried out

advantageously in an apparatus which consists of an

injectionmoulding-cylinder capable of being heated, preferably in

zones, at the rear end of which is provided a pressure means capable

of applying a pressure of more than 1500 kilograms per square

centimetre and the front end of which is provided with a constriction

which amounts to at least 50% (calculated as reduction in

cross-section as compared with the original cross-section) and which

has a length of at least half the diameter of the original

cross-section. The injeetion-moulding-cylinder is preferably

constructed so that it holds no more than 2 to 3 times the amount of

polymer which is to be used as a maximum in a single

injection-moulding operation. Thus the residence time of the polymer

in the injeetion-moulding-cylinder and consequently the thermal load

is kept small. Usually the pressure means will be a piston which fits

into the injection-moulding-cyiinder. The constriction is preferably

formed by a mern- ber which temporarily splits up the stream of

polymer into a plurality of partial streams.

A torpedo having longitudinal grooves or longitudinal ribs arranged in

the interior of the inj ection-moulding-cylinder is especially

advantageous. The apparatus is preferably made of material which

resists corrosion, as for example from a stainless steel.

An embodiment of apparatus according to the present invention is shown

in the accompanying drawing in which :-

Figure 1 is a sectional elevation; and

Figure 2 is a cross-section on the line a-b.

An injection-moulding-cylinder 1 is provided with resistance heating

coils 4. A pressure means is shown at 2 and the constriction is formed

by a torpedo 5 having longitudinal grooves or ribs which split up the

stream of polymer temporarily into a number of partial streams by

virtue of the shape thereof. The polymer, which is introduced at 6,

passes through the nozzle 3 into an injection mould (not shown).

The ibliowing examples will further illustrate this invention but the

invention is not restricted to these examples.

EXAMPLE 1.

A polyvinyl chloride having a R-value of 55 obtained by suspension

polymerisation is granulated with 2% of lead stearate as stabiliser

and then lvorked up in an injection moulding machine. In the

injection-mould ing-cylinder having an internal diameter of 30

millimetres, the material is heated by electrical resistance heating

coils to 1600 C.

in a first zone, to 1750 C. in a second zone and to 1s0O Cl. in a

third zone. The heated polymer is forced with a pressure of 1600

kilograms per square centimetre through a constriction of 75%

(calculated as reduction as compared with the original cross-section)

having a length of 60 millimetres, and through a nozzle of 2

nijilimetres diameter during the course of 15 seconds into a mould

preheated to 500 C. Test rods from the moulding thus obtained give a

tensile strength of 550 kilograms per square centimetre and a breaking

elongation of 20 to pro%. The mouldings obtained are practically

without discoloration and the apparatus used does not show any

corrosion at all.

EXAZPLE'.

If a suspension polymer of vinyl chloride having the K-value 70 and

stabilised with 2% of an organic sulphur-tin compound is used as

described in Example 1 under a pressure of 1700 kilograms per square

centimetre and a temperature of 170j180 ( 1S5" C., practically

undiscoloured test rods are obtained having a tensile strength of 620

kilograms per square centimetre and a breaking elongation of aO9. In

this case also, the apparatus is not eorroded.

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* GB785997 (A)

Description: GB785997 (A) ? 1957-11-06

Method for the recovery of uranium products from solutions containing

hexavalent uranium










785997 : Date of Application and filing Complete Specification: Aug

18, 1955.

No 23845/55.

Application made in Sweden on Aug 20, 1954.

Complete Specification Published: Nov 6, 1957.

Index at acceptance: -Class 1 ( 2), C 3 CXM International

Classification:-CO 1 g.

COMPLETE SPECWIICATION Method for the Recovery of Uranium Products

from Solutions containing Hexavalent Uranium We, A B ATOMENERGI, a

joint stock company organized according to the laws of Sweden, of

Lovholmsvdgen 5, Stockholm 9, Sweden, 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 conventional method for precipitating uranium from aqueous

solutions containing hexavalent uranium is precipitation by the

addition of ammonium hydroxide, alkali metal hydroxides or alkaline

earth metal hydroxides.

Thereby a product is obtained which is very difficult to separate from

the solution by sedimentation, filtration or centrifuging, whether the

solution contains foreign ions or not Owing to local excess

concentration which cannot be prevented on the addition of the

neutralizing agent the product becomes heavily polluted by

co-precipitation of other ions if such ions are also present in the

solution If the product is later to be subjected to processes in the

dry state it will usually be necessary to grind and screen the dried

product These methods for the recovery of hexavalent uranium from a

solution are thus laborious, result in pollution of the product and

often make succeeding processes for the manufacture of uranium metal

complicated.

In the method according to the present invention these drawbacks are

completely avoided Uranium is precipitated in the form of a compound

which is exceedingly easy to filter, and the process is easily carried

out, easily controlled and cheap The method consists in dissolving in

the aqueous solution containing hexavalent uranium one or more amides

to form a homogeneous solution and heating the solution to cause the

amide to hydrolyse whereby the p 1 H value of the solution increases

and ammonium uranate is precipitated The precipitate settles very

rapidly to a small end or ultimate volume and can very easily be

lPrice 3 s 6 d l separated from the solution by filtration or 45

centrifuging Preferably an amide of an easily volatile acid or an acid

with a p K value greater than 3 is used and of these preferably

carbamide or acetamide As a rule carbamide is preferred as it provides

a quicker and more 50 complete precipitation In order that hydrolysis

of the amide shall take place quickly the solution is heated,

preferably to 90 -1 '15 C.

Due to the fact that the amide is homogeneously distributed in 'the

entire solution no 55 great local excess of the neutralization agent

occurs when the amide is hydrolysed on heating It follows that a well

formed product of high volume weight and having less impurities on

account of enclosures and adsorptions is 60 obtained.

After drying the product easily falls to a powder of very uniform

grain size It is, therefore, well suited to be used without grinding

and screening In operations in the dry state, 65 for instance,

according to the fluidized bed principle The dried product is not

dusty to any material extent which minimizes the risk of toxic effects

and makes the product easy to handle 70 When carbamide is used ammonia

and carbon dioxide are obtained on hydrolysis It would be expected

that the carbon dioxide split off would form soluble complexes with

uranium and that the process would not give so favour 75 able a result

as it, surprisingly enough, has given.

On the above hydrolysis of carbamide the p H value of the solution

increases causing the uranium to precipitate Experiments carried 80

out have indicated that the ultimate p H value obtainable at a given

temperature depends on the percentage of ammonium salts in the

solution By controlling the percentage of ammonium salts in the

solution, it is therefore 85 possible within certain limits to adjust

the maximum or ultimate p H value This p H value can be so chosen that

the uranium will 111 'I1 1 be practically completely precipitated

while, on the other hand, hydroxides of, for instance, Cd, rare earth

metals, Hg, Be, Fe", Cr, Ni, Co, Zn, Pb, Mn, Mg, and Ca have not

started to separate It is thus possible to obtain a product free from

a multitude of undesired metal ions by using at the end phase of the

process a p H value within the range 4 5-7 and preferably 5-6.

EXAMPLE 1.

Three separate solutions of uranyl chloride, sulphate and nitrate

respectively, containing grams per litre of uranium were adjusted with

ammonium hydroxide to a p H value of 3 Then 1 gram carbamide per gram

uranium was dissolved in each clear solution and the mixture was

heated to 100-103 C with stirring Within 30 minutes uranium started to

separate out, and within 2 hours the precipitation was complete.

The precipitates settled very quickly to a small ultimate volume The

products were filtered off on a Bichner funnel and washed with warm

water at 60 C under vacuum.

For the sake of comparison solutions of the above composition were

precipitated with a % solution of ammonium hydroxide at 951000 C,

whereafter the precipitates were stirred for 1 hour before

sedimentation and filtration which was also carried out on a Bichner

funnel under the same vacuum The results are given in the following

table.

TABLE

Filtration, funnel Product dried The solution Precipitation diam 5 5

centimtr at room temp.

Filtration velocity at washing with warm Cake water Filtrate thick (

600 C) milliUraniumM iii end ness, litre/sq gram/ gram/ Uranium

Afillih end centi meter/ litre milligram/lit litres Anion p H metres

hour of U % U % NH 3 litre 200 Cl Hydro 6 5 0 8 360 6 73 0 1 4 1 14

lysis 200 504 of carb 6 0 1 0 650 52 64 6 3 5 1 36 amide 200 NO 3,, >

6 7 0 5 570 6 72 0 1 3 1 79 200 Cl 25 % 6 7 2 0 4 1 1 73 9 1 9 1 05

ammonia 200 504 1,, 5 6 1 5 4 8 80 64 6 3 7 1 05 200 NO 3 J,, 6 0 2 0

3 2 2 72 8 1 6 1 22 \ O 785,997 The filtration velocities refer to

washing with 600 C water of equal amounts of uranium on the filter It

will be readily seen that the products obtained by precipitation by

hydrolysis of carbamide gave filtering velocities of quite a different

order from those obtained by precipitation by addition of ammonium

hydroxide.

EXAMPLE 2.

A solution of uranyl nitrate containing 100 grams of uranium per litre

was adjusted with ammonium hydroxide to a p H value of 3 In the clear

solution 2 5 grams acetamide per gram uranium were dissolved, and the

solution was then heated to 100-103 C with stirring.

Within 30 minutes uranium began to precipitate After 5 hours a p H of

4 6 was attained.

The precipitative settled quickly to a small end volume The product

was filtered on a Biichner funnel The percentage of uranium in the

filtrate was 4 grams per litre The product was washed in the same

manner as in Example 1 The velocity of filtration on washing was 310

litres per square meter per hour.

A comparison with Example 1 indicates that the precipitation of

uranium proceeds quicker and more completely with carbamide than with

acetamide.

EXAMPLE 3.

Hereinbelow the results of some experiments are given showing what p H

values can be obtained at 100-103 C and with various percentages of

ammonium salts in the solution.

Salt NH 4 NMM (NH 4)"SO 4 gram/litre 300 end p H 6.3 5.9 5.5 5.8 5.4

It is seen that within given limits it is possible by variation of the

percentage of ammonium salts to obtain the desired end p H at the

precipitation of uranium by hydrolysis of carbamide.

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* GB785998 (A)

Description: GB785998 (A) ? 1957-11-06

Method for the preparation of di-halo-glycol diethers










785,998 Date of Application and filing Complete Specification: Aug 26,

1955.

e% S ark No24620/55.

Application made in France on Sept 16, 1954, Co plete Specification

Published: Nov 6, 1957.

Index at acceptance:-Class 2 ( 3), CIE 4 K( 2: 6: 8: 9), C 1 G 2 B( 1:

2), CIG 5 (A: B), C 1 G 6 (A 2: A 3:

B 3).

International Classification:-CO 7 c, d.

COMPLETE SPECIFICATION

Method for the preparation of Di-Halo-Glycol Diethers We,

BOZEL-MALETRA SOCIBTE INDUSTRIELLE DE PRODUITS CHIMIQUES, a body

corporate organised under the laws of France, of 38, rue de Lisbonne,

Paris, France, 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 method for the preparation of

dihalo-glycol diethers, as well as to the products obtained by this

method.

It is known that halo-methylated ethers, having the general formula

RO-CH 2 X, may be obtained by reacting formol with an alcohol R-OH in

the presence of a hydrogen halide HX, X being a halogen and R an alkyl

radical.

Said halogenated ethers are commonly used as intermediate products for

various organic syntheses, particularly for obtaining chloromethylated

derivatives according to the formula R 1-CH 2 C 1.

Such methods, however, have not made it possible heretofore to prepare

compounds according to the general formula R-O-CHX -CHX-O-R or XHC CHX

1 U 0 O R' An object of the present invention is to provide a method

for the preparation of dihalodiethers derived from ethane and having

the general formula ( 1) XHC-CHX l l 0 O R 1 univalent aliphatic

hydrocarbon radicals or together constitute a divalent aliphatic

hydrocarbon radical thus forming a ring Preferred compounds are those

in which R and R' are methyl or ethyl radicals or in which R and R'

together are a -CH 2-CH 2 radical.

The method according to the invention consists in causing an alcohol

or a glycol and a hydrohalic acid to act on glyoxal.

According to the invention, glyoxal is dissolved, in the form of a

concentrated aqueous solution or in powdered form, in, an excess of

alcohol or of glycol, the solution is cooled, the hydrohalic acid is

introduced therein, preferably in a gaseous condition, the

dihaloglycerol diether thus formed is separated either by

crystallisation from the mixture or by extraction by means of a

solvent.

The alcohols capable of being used for working the method are, for

example, methyl alcohol, ethyl alcohol and butyl alcohol As glycols,

ethylene-glycol may be more particularly mentioned.

Hydrochloric acid or hydrobromic acid may be used as hydrohalic acids

according to the final products desired.

For facilitating the dissolution of the glyoxal, a certain amount of

hydrohalic acid may be introduced in the solution as it is being

formed Iit is also possible to add the alcohol or glycol to the

solution containing glyoxal after the gaseous hydrohalic acid has been

introduced.

Finally methylene chloride, carbon tetrachloride, ethyl ether and the

like may be used as extraction solvent.

The dissolving of the dialdehyde may be facilitated by heating and/or

stirring the mixture.

The temperature of introduction of the hydrohalic acid should be

chosen sufficiently low so that the dihalo-glycol diethers formed do

not react with the alcohol in excess; temperatures below 25 C are

preferably used.

The method when carried out under the above conditions provides a

number of new in which X is a halogen and R and R' are compounds which

are clearly characterised both chemically and physically; they are

crystalline solids or liquids insoluble in water but easily soluble in

organic solvents In the presence of water, they undergo saponification

to give the starting materials In the absence of water they are

completely stable and may be purified by distillation.

These dihalo-glycol diethers are extremely valuable in organic

synthesis due to the high reactivity of their halogen atoms; they

condense in particular with all alcoholic or phenolic -OH groups thus

making possible preparation of numerous new diacetals; they also react

with the substances possessing an H atom, particularly with carboxylic

hydrogen, or an active metal atom.

On the other hand, the alkoxy -R-Ogroup of these dihalo-glycol

diethers can also condense with substances of the aromatic series;

this provides an easy and economical synthesis for substances of the

diphenylethane series according to the reaction.

2 Ar H + R-O-CHX-CHX-O-R Ar-CHX-CHX-Ar + 2 R-OH in which Ar is an aryl

radical.

When zinc reacts with the dilialides thus prepared, derivatives of

stilbene are obtained.

By ithe action of alkaline reagents, it is possible to obtain

halogenostilbenes Ar-CH= CX-Ar or tolanes Ar-C= Ar, or other like

derivatives.

Finally, the invention provides an important advance in the synthesis

of some products which were heretofore accessible only by means of

difficult methods Such is the case, for example, of the preparation of

2,3-dichlorodioxane which could only be obtained heretofore by

chlorination of dioxane but which can now be prepared according to the

present invention, from glyoxal, ethylene glycol and hydrochloric

acid.

EXAMPLE 1

220 parts in weight of 78 % powdered glyoxal are mixed with 425 parts

in weight of methyl alcohol, a small amount (about 10 parts) of

gaseous hydrochloric acid is introduced into the mixture and the

mixture is heated with stirring at 40-50 C until the glyoxal is

completely dissolved.

The mixture is then cooled ito between 0 and 15 WG, and 365 parts of

dry, gaseous hydrochloric acid are introduced over a course of 4

hours.

An abundant mass of crystals are formed which are dried and rinsed

with a small amount of cold methanol followed by a small amount of

cold ether 380 parts of pure 1: 2dimethoxy-l 2-dichloroethane are

obtained.

Melting point 70 50 C Chlorine content 44 2 i% (calculated content

44.6 %) Yield 80/% EXAMPLE 2

A mixture of 220 parts by weight of powdered glyoxal ( 78 %) and 425

parts of methyl alcohol are treated as in Example 1, the hydrochloric

acid being replaced by 810 parts of gaseous hydrobromic acid.

1: 2-dimethoxy-1: 2-dibromoethane is obtained and then dried and

immediately recrystallized from carbon tetrachloride The final nroduct

has a melting point at 720 C and a bromine content of 60 %'

(calculated content 64.5 %).

EXAMPLE 3

1330 parts of methylene chloride are mixed with a solution of 50 C%

glyoxal comprising 435 -parts in weight of glyoxal ( 100 %) dissolved

in 435 parts of water and the mixture saturated with gaseous

hydrochloric acid, the temperature being maintained at about O GC.

690 parts of ethyl alcohol are then slowly introduced, while

continuing the bubbling of hydrochloric acid through the mixture and

while maintaining the temperature in the vicinity of 00 C.

After saturation, the lower layer, consisting in a mixture of 1:

2-diethoxy-1:2 dichloroethane and methylene chloride, is separated

off, dried over calcium chloride and a double distillation carried out

under reduced pressure.

1100 parts of diethoxydichloroethane are thus obtained distilling

under 40 mm Hg at WC, having a specific gravity of 1 135 at C, a

melting point at 17 WC and a chlorine content of 37 1 % (calculated

content 38 %o).

EXAMPLE 4

Into a well-stirred mixture of 500 parts by weight of a 60 % glyoxal

aqueous solution, 284 100 parts of ethylene-glycol and 800 parts of

carbon tetrachloride, is introduced gaseous hydrochloric acid under a

slight pressure until the mixture is saturated, the temperature being

maintained below 50 C 105 After standing for a few hours at room

temperature, the lower layer, consisting of carbon tetrachloride and

2: 3-dichlorodioxane, is decanted; the upper layer is then again

saturated with hydrochloric acid in the pre 110 sence of a further

amount of 800 parts of carbon tetrachloride These operations are

repeated three times.

The four mixtures of carbon tetrachloride and 2: 3-dichlorodioxane

thus obtained are 115 bulked together and re-distilled under reduced

pressure.

193 5 parts of pure 2: 3-dichlorodioxane are finally obtained,

distilling under 23 mm Hg between 89 and 95 WC 120 785,998 solution of

glyoxal, in which alcohol or glycol is then introduced.

8 A method according to any one of the preceding claims, in which

glyoxal, ethyleneglycol and hydrochloric acid are used as starting

materials for obtaining 2: 3-dichlorodioxane.

9 Dihialo-glycol diethers derived from ethane of the general formula:

The reaction gives practically rno secondary products.

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