MOORE-“ACTION OF SOME OXIDISING AGENTS O N COTTON.” [Sept., 1915. 180

sulphate. The colour of the silk was lighter and better after treatment with Glauber’s salt than when treated with water only, and a slight scroop was also developed by Glauber’s salt treatment.

The only theory known to us which can furnish a rational explanation of this stripping of animal ibre substance by neutral sodium sulphate is he theory of neut)ral salt reactions advanced t i previous communications (Eoc. ez‘t.).

Technical College, Bradford.

The wool was much felted after the fifth treatment, and i t was difficult to draw con- clusions as to the lustre and handle. In colour, however, a pronounced difference was shown, the wool which had undergone Glauber’s salt treatment being not so brownish as the wool which had been treated with water alone although the former had undergone more severe losses in weight. It has been observed previously (Fort and Lloyd, this Journal, 1914, p. 77) that the yellowing or browning of wool appears to be due to basic constituents of the wool, and is suppressed by acid treatment (e.g., with sul- phuric acid). The tendency for a faintly acid state to be set up on wool when treated with Glauber’s salt solutions has been described previously by one of us, and this may be re- sponsible for the colour of the wool being better maintained in presence of Glauber’s salt than in a treatment with water only.

A difference in the affinity of the samples for a neutral solution of pure Crystal Scarlet was also noticed. The wool treated with Glauber’s salt took up more dye, i.e., using 0.0399 grm. actual dye, analysis of the exhausted liquors by titration with titanous chloride showed an absorption of 0.0012 grm. dye by the water- treated sample and 0.0028 grm. dye by the sample which had received successive Glauber’~ salt treatment. This effect of Glauber’s salt on wool was dealt with in previous communications and an explanation was assigned similar to thal just given for the effect upon the colour of thc wool itself.

A similar experiment to those recorded in Table I. was performed on three similar sample5 of pure boiled-off silk, and the samples weighec after conditioning together.

Untreated silk weighed 443240 grms. ; silk treated with Glauber’s salt, 4,7300 grms. ; sill! treated with water, 4.7590 grms. The effect 0‘ Glauber’s salt therefore has been to cause tht loss of 0.0290 grm.=0.6 per cent. of silk sub stance. Colour differences were not so market as to furnish definite conclusions, but a decidec scroop was given by the Glauber’s salt treat inent (after thorough rinsing and drying), whicl the other sample did not show. This agair presumes some faint acidity on the fibre (c.f wool above).

Finaliy we have performed similar experi ments on the same silk in the gum, employing however, two hours’ heating instead of three but 20 per cent. Glauber’s salt as before. I seemed possible that such a treatment migh find application in soupling or partially degum ming for ecru silk. The estimation was made b: weighing the evaporated extracts in duplicab experiments.

Water removed 0.1398 grm. and 0.1350 grm of gum. Glauber’s salt solution removed 0.1851 grm. and 0.1814, or 3.6-3-7 per cent., of gum. afte allowance had been made for sodium sulphatc left behind. About 0.5 or 1 per cent. gun therefore was removed by the action of sodiun

The Action of Some Oxidising Agents on Ceihiose.

H ~ R O L D MOORE, M.Sc.Tech.

These investigations were undertaken with 5 view to ascertaining the quantitative relation- &ips which exist between the concentrations of 3olutions of various oxidising agents, and the srnounts of oxycellulose formed by these golutions under varying conditions. It is well known that the formation of oxycellulose is one of the greatest difficulties of the bleacher, and that its existence is the cause of large losses to dyers and others engaged in the production of cotton goods. It appeared to the author that if the conditions which bring about the formation of oxycellulose were more fully under- stood, these conditions might be more success- fully avoided.

In all cases the cellulose taken was cotton, and the results will probably not apply to other forms of cellulose without modification. The raw yarn (2130 American) was soaped and washed out, no bleaching taking place before treatment with the oxidising agents.

It will be evident that i t was first necessary to find a suitable method for detecting and esti- mating the presence of oxycellulose in a bleached sample. Two methods have been employed, the first being by means of Fehlimg’s solution, and the second a method based on the greater affinity of oxycellulose for several basic dye- stuffs-notably for Methylene Blue. Pre- liminary experiments were carried out with a view to finding which method was preferable for the estimation of oxycellulose. The Fehling’s solution method is as follows :-About three grins. of the sample are boiled for 15 minutes with 100 cc. of Fehling’s solution and 200 cc. of water. The cotton is washed repeatedly, and the washings added to the original solution. The amount of copper reduced may then be estimated by a titration of the residual liquid with titanous chloride. The copper value of the original Fehling’s solution may also be deter- mined in the same manner. The amount of copper precipitated is supposed to be roughly proportional to the oxycellulose present. The copper precipitate may be estimated gravi- metrically if preferred.

Sept., 1915.1 MOORE-"ACTION O F SOME OSlDlSING AGENTS ON COTTON." 181

of the Methylene Hue absorbed by the cotton, the dyed skein of cotton is immersed in 50 cc.

In the experiment two skeins of raw American yarn of approximately 10 grms. were weighed out ; skein A was then treated with cold wat,er for 60 minutes, and skein B with a bleach solution containing 4% grms. chlorine per litre for 60 minutes.

The were as :-- ~- ~~~~ -~

After washing and drying, a sample of each of the two skeins was taken and the oxycellulose estimated by the Fehling's solution method. It was found that skein A precipitated 3.81 per cent., and skein B precipitated 4.12 per cent. of copper (calculated to the weight of the cellulose).

0,0732 one and was eventually employed throughout. D 0'00307 0.234 0.0516 ~ 0'00fi1-1- "'-"W

In the, various series of experiments 10 grm. E , 0,00151 , 0,252 , 0.0301 skeins of 2/30 American yarn were invariably 0.255 ' 0.02.54

The same two skeins were now dyed with Methylene Blue (4 per cent.), and the amount of dyestuff on the fibre estimated directly by the method of Knecht. The results were as follows :-A contained 0.285 per cent., and B contained 1.06 per cent. of Methylene Blue (calculated to the weight of the cellulose). This shows the results obtained by the Methylene Blue method to be much more strongly marked than was the case by the Fehling's solution method, the bleached sample having absorbed nearly four times the amount of Methylene Blue taken by the unbleached yarn.

0.2753 0'2856 0.2821 0.2804

Further experiments were made on tlhe relative figures obtainecl for cellulose unbleached and for cellulose oxidised as completely as possible (until the fibre had fallen to pieces). These results were found to favour still more the estimation of oxycellulose by the Methylene Blue method.

At this point the question arose as to the method of determining the Methylene Blue absorbed by the fibre ; this may be done either by an estimation of the Methylene Blue left, in the filtrate or by an estimation of the Methylene Blue on the fibre, as given by Knecht.

The former method is found in practice to have several serious disadvantages-chiefl y the fact that the exhaust liquor and washings occupy such a large bulk that on titrating considerable difficulty is experienced, the end point of the titrations is not distinct when a large volunie of water is employed, and also the water has always some oxidising effect on the titanous chloride due to air in solution.

a morclant., t,he washing had to be limited to a fixed number of ininiersions in water, the skeins being wrung out in a machine.

In most of the experiments undertaken, the oxidising agent employed was filtered bleaching powder solution ; in some cases sodium hypo- chlorite solutions were employed, and in some of the later experiments potassium perman- ganate was used.

The resnltrs givcn in a11 the following experi- ments are only comparative. The series were always carried out together and in similar dye- pots-the latter being always immersed in the same water-bath in order to ensure an equality of temperature. In all cases blanks were carried out.

Ten-grm. skeins were treated for two hours a t a temperature of 15' C. with 200 cc. of the varioiis bleach solutions, after which they were taken out and well rinsed, first with very dilute hydrochloric acid. to wad^ out any lime which might he present,, and then with water. The skeins were then dyed in 100 cc. of Methylene Blue, 2 per cent. (011 the weight of cotton) being employed. The results are given in the following table :-

The results indicate the general effect of the various bleaching solrttions, the amount of Mcthylene Blue corresponding to the strength of the bleach.

A furtzher series of esperiniciits were ca,rried out at, 45" C. ; t'he washing of the dyed skeins previous to est.imntion was -restricted to five immersions in cold water and pressing once between rollers.

MOORE-"ACTION OF SOME OXIDISING AGENTS ON COTTON." [Sept., 1915. 182

0.0 B A I ;::; 0.4

7.65 ' 1.0 2.0

E F 7.65 4.0

1 ;::: 1 3.0

solutions a t different temperatures and a t varying concentrations, it was considered ad-. visable to note the effects produced by the addition of acid to the bleach solution.

The results in the accompanying table were obtained, using 100 cc. of bleach solution :-

0.0294 0.0214 0.0161 0.0130 00174 0.0321

~

NO.

A €3 C D E

Amonnt Grm. of

Addition. on Yarn. of Met.hy1ene Blue

~~~

Grm. of CI. per cc.of Bleach.

0.00601 0.00601 0.00601 0'00601 0.00601

I--- ~~

10 cc. N/HCl 50 ,, ,,

100 10 cc. ?5y0 HCl No addition

0.0371 0.0206 0.0164 0.0237

* 0.141 0

Due to the high temperature (45" C.), the effect of even small quantities of acid has been to release chlorine, which is expelled from solution, thus reducing the amount of oxidation. The large amount of acid in D has caused the formation of hydrocellulose, accounting for the comparatively high Methylene Blue value. It will be observed that all the values are much below those obtained with the bleaching agent alone in E.

As the effects of additions of hydrochloric acid had been more drastic than was desired, acetic acid was used in the next series, which was carried out a t 15" C. for samples A to E, and a t 45" C . for those from F to J.

No, I Grm.ofC1. per litre.

~-

EFFECT O F ADDITIONS OF ACETIC ACID ON BLEACH AT 15" C.

Grm.ofNaOH Grm. of added. Methyleue Blue.

1 RrIn.ofC1.

No. ' Bleach Solution. per ec. of

A B C

~

Glacial Grm. of Acetic Acid I Metliylene Blue

added. , on Yarn.

10.8 7,2 5.4

A ' 0.00479 B 0.00479

0.00479 g 0.00479 E 0.00479

0.00479 0'00479 0.00479 r" ! 0.00479

J 1 0.00479

i 1 cc.

10 cc. 20 cc. 1 0 cc. 1 cc.

5 cc. ~

5 cc. I

I 10 cc. I 20 cc. 0 cc.

0.0352 0.0180 0.0197 0.0223 0.0587 0.1062 0.0249 0.0257 0-0210 0.1425

I I I

It was anticipated that the effect of slight additions of acid might be to liberate thc chlorine slowly and thus increase oxidation this, however, is proved by the results not to bc the case.

Egect of Addition of Alkali.-The effect of adding alkali on the production of oxycellulosc was next investigated. In this case the skeins were dyed with 2 per cent. of Methylene Blue in 200 cc. total volume of dyebath at 15" C The other figures governing the conditions oj the experiment are given in the accompanying table. The special bleach solution used provec to contain no excess alkali on analysis by thc hydrogen peroxide method.

Grm.of CI. I Grm.of Grm. of

Bleach. added. on Yarn. No. 1 percc. of NaOH 1 Methylene Blue

A 11.47 B 11.47 C 11.47 D ~ 11.47 E 11.47

11-47 F ! 11.47

I 1 11.47 H I 11'47

0.0 ' 0.1 I 0.5 1.0

3.0 4.0 5.0

0.0133 0~0100 0.00865 0~0080 0-00865 0~0100 0.0153 0.0153 0.0167

It was next decided to carry out a series of tests on the oxycellulose values found when permanganate is employed instead of chlorine as oxidising agent.

The concentration of the permanganate solu- tions is stated in terms of oxygen, assuming that three atoms of oxygen can be given by each molecule of potassium permanganate in neutral solution.

In experiments in which permanganate was employed, the skeins were immersed after oxidation in oxalic acid and sodium bisulphite solution, in order to discharge the precipitate of manganese dioxide from the fibre, and finally washed with a large quantity of water until all traces of the bisulphite was removed. The skeins were then dyed with 2 per cent. Methylene Blue bath in the usual way.

In the first series varying amounts of per- manganate were used, the experiments being carried out a t 15" C., and the immersion lasting one hour.

The results are shown in the accompanying table :-

Concentration of

of Oxygen per litre. No. I Permitnganate as e m . Grm. of Methylene Blue

on Ya.rn.

0.0443 0.0369 0.0372 0.0276 0.0160 0.0154 0.0154

Sept., 1915.1 ATACK-" USE O F M E T H Y L E N E B L U E I N ANALYTICAL CHEMISTRY." 183

K O .

~ - ~~ -

The results are very similar to those obtained with chlorine bleach.

In a further series the temperature was maintained at 35" C. during the oxidation, the results being as follows :-

Amount of 1 Total I Grni. u t

a8 grm. Oa. Solution. o n Yarn. Permanganste Amount of Yethyleor Uliie

~ -~ I

Concentration of

of Oxygen per litre. Xo. Pernianganate as grm.

A 10'8 B I 7.2 c 5.4

2.7 1'35 : I F O.G'i5

~ _ _ _ _ _ _ _ ~ ~

A B C D E F

Grin. of JIetliylene Blue on Yarn.

1.08 100 grms. 0.0830

1.08 300 ,, 0,0849 1.08 400 ,, 0'0521 1.08 500 ,, 0.0341 1.08 Infinite dilution1 0.0154

1.08 200 1 , 0.0210

0,0644 0.0468 0.043G 0.0321 0.0228 0.0208

~

The results are of the same type as a t 15" C. In a third series, using permanganate, the

amount of oxidising agent was kept constant, but the volume of the bath was varied, in order to decide whether the effects indicated in the previous experiments were actually due to concentration, or whether the total amount of the oxidising agent was the factor influencing the results. If the total quantity of oxidising agent alone is affecting the results, the result of plotting a curve would give a straight hori- zontal line, but if concentration be the influenc- ing factor, the results on plotting the Methylene Blue value against the total volume of solution would give a hyperbolic curve. Actually the following results prove that the latter is correct :

Triisile I Strengtll I Strength of Bleacliin 'a'uyle. 1 grm. CI. per litre.

i 15'3

R t 10.2 1 1 . 7 7 C ' 7'65 12.50

3.83 12.50 2.65 14.47 1.53 12.82

f G I I 13.61

~ _ _ pp

-~

The results appear all in sequence except for the skein E. The abnormally high value for the tensile strength given by this member of the series can only be accounted for by some differ- ence in the cotton, although a further experi- ment gave a similar result a t this concentration. The greatest care was taken to prevent any moisture entering the fibre.

School of Technology. Manchester.

Methylene Blue and i t s Use in Analytical Chemistry.-I.

F. W. ATACK, M.Sc.Tech., B.Sc. (Loncl.), A.I.C. Of the various dyestuffs and other coloured

substances which have been suggestecl for use in analytical chemistry, none appear to the author t o be capable of such wide application as the thiazine dyestuff Methylene Blue. This dyestuff is characterised by (1) great fastness to light, 0.5 per cent. solutions having been preserved in the light for three years in contact with air without any measurable (i.e., below 0.1 per cent.) decomposition occurring ; (2) the stability of an acid solution of this basic dye- stuff and of its leuco compound ; (3) the relative ease with which the dyestuff is converted quantitatively into its leuco compound by reducing agents in acid solution, and vice versa by oxidising agents ; and (4) its high tinctorial power ; for example, it is possible to titrate with an N/SOO or even more dilute solution of Methylene Blue. There appears to be no reason why the use of Methylene Blue should not be much more frequent; it is readily obtainable in a sufficient state of purity, and, as will be shown, it is capable of far wider application in the laboratory than most reagents in common use.

It is, therefore, considered that it will be an advantage to collect the information available with regard to the use of Methylene Blue in analytical processes, and details will be added of several methods, which, although they have been used with success by the author for several years, have not previously been published.

It is proposed to precede the analytical section of the paper by an account of certain researches on Methylene Blue itself and of its leuco-com- pound (Methylene White), with the latter portion of which the author had the assistance of A. Embleton. In certain respects these researches are unfortunately somewhat incomplete, but as i t seems improbable that the author will have an early opportunity of completing the work, it would appear best to publish the results to date.

The author desires to acknowledge his indebtedness to the Research Fund of the Chemical Society for a grant which covered the expenses of certain portions of the research, and also to Messrs. Claus & Co., of Clayton, Man- Chester, for their kindness in providing the pure samples of Methylene Blue used throughout