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CELLULOSE INDUSTRY

THE JOURNAL OF THE CELLULOSE INSTITUTE

, TOKYO, JAPAN

VOL. 15 August, 1939, No. 8

ABSTRACTS FROM THE TRANSACTIONS

STUDIES ON XANTHATE 1)

ON THE REACTIONSOF SOME XANTHICACIDSWITH

METALLICELEMENTS

by K. Atsuki and T. Takada.

(Recived 17th, June, 1939)

A number of xanthates of various alcohols and metals were prepared, and the reaction of

their formation and their characteristic properties were studied. comparing with cellulose xanthates.

Experimentals.

1. Preparation of sodium xanthates of various alcohols. The sodium xanthates of various

alcohols were prepared as follows. The pure alcohol was saturated with sodium hydroxide and added

with carbon bisulphide gradually while cooling. After the reaction was completed, a large quantity

of ether was added, and by rubbing the wall of the reaction vessel, beautiful needle or flaky crystals

were obtained. Then the crystals were dissolved in a small quantity of alcohol used in xanthation,

and crystallised again from ether. Thus the following 6 kinds of xanthates were prepared.

All these salts are needle like crystals having the characteristic unpleasant odour, insoluble in

ether, and soluble in alcohol. Their solubility in water decreases with the increase of molecular

weight of alcohols.

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5. Aluminium-Group. Aluminium : Aluminium xanthate was obtained as a yellow precipitate

when the solution of xanthate was added to a saturated A1C13 solution. It is easily soluble in water

and easily decomposed by hydrolysis. It may be reasonably assumed that the coagulation of viscose

with aluminium salts does not follow the Hoff-meister's law because of the characteristic solubility

and stability of the aluminium xanthate itself.

Cerium; a yellowish white precipitate, which changes into a white precipitate of cerrous

xanthate on warming. was precipitated from the solution of xanthate by the addition of the saturated

Ce(NO3)3 solution.

Erbium Er(NO: , Dysprosium Dy(CH;jCO2);., Lanthanium La(-NO:,)::, Ytterbium Yt(CH3CO2)s;

no reaction was observed at room temperature.

6. Thallium Group. The salts of this group are insoluble in water, and not attacked by

dilute inorganic acids.

7. Titanium Group. Titanium: A mixture of Titanium and xanthicc acid was produced from

the solution of santhate with the addition of an acidic solution of titanium.

8. Tin Group.

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. Vanadium Group. No reaction is expected to occur in the case of non-metallic elements

of this group.

Niobium : The solution of Niobium is so acidic that the reaction can not be clear.

Tantalum : Tantalum is a non-metallic element.

Vanadium: V02C14 produces a dark brown precipitate of xanthate from the solution of

sodium-xanthate, which is soluble in alcohol and ether. showing a reddish brown colour.

10. Nitrogen Group.

11. Cromium Group.

12. Sulphur Group. Selenium, Terbium : Due to the non-metallic properties of these metals,

no reaction is expected to occur.

13. Manganese Group. Manganese: A yellowish white precipitate of manganese xanthate

was obtained from the solution of sodium xanthate with the addition of the solution of MnC12.

Mn-methyl-xanthate is soluble in water, and the other alcoholic xanthates are soluble in hot water.

14. Iron Group. The xantic salts of this group have a characteristic colour, and are soluble

in alcohol and ether. As the colour of Cobalt xanthate is so characteristic, it may be used to

detect the xanthie radicals.

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15. Platinum Group. Platinum : H2PtCl6 produced a yellowish orange precipitate from the

solution of methyl-, butyl-, or amyl xanthate

, and an orange precipitate from ethyl-, or propyl

xanthate, and a yellowish white precipitate from benzyl xanthate. These platinum salts are soluble

in alcohol and show a bright, golden colour.

Rhodium H2RhC16, palladium H2PdCI6i Iridium H2IrC16 produced an orange precipitate from

the solution of ethyl xanthate, which are soluble in ether. and are of golden yellow colour

.

. The solubility of xanthate in ether. As the valency of metal of salt of the same acid

radical is different, the solubility of the salt in some specific solvent is also different, and this relation

is easily supposed to exist with xanthates. The solubility of the xanthates of various metals, there

fore, were examined, . using ether as solvent. All the xanthates of monovalent metals such as Na,

K_ TL Ag, Au were insoluble in ether, but the xanthates of polivalent metals such as Ca, Sr, Ba,

Cu, Cd, Zn, Co, Ni, He. Mn. Sn, U02, Pb, Hg, Bi, Cr, Au, Tl, V02, Pt were soluble in ether.

W The relation of the valency of metals to the formation of various Xanthate s.

A) On adding the solution of trivalent Au salt, HAuCl, to the solution of Na-xanthate, an

orange ether soluble precipitate of the xanthate of An... (RoCS2)j An was obtained, but it changed

immediately to a white ether insoluble precipitate of the xanthate of Au, ROCS,, Au. The same

results were obtained with the reaction of other polivalent salts as follows.

B) The bivalent cobalt salt, trivalent bismuth salt, and quardvalent vanadyl salt were added

to 3/100 Mol solution of Na-xanthate respectively and the corresponding xanthates were obtained as

precipitate, which were filtered and weighed. The yield was as follows. Co: 89.8 , Bi: 29.5%,

VOA: 21.6%.

V. Cellulose xanthate of various metals. It was found by our spectrochemical studies that

the constitution of sodium cellulose xanthate is identical with the sodium xanthate of methyl, ethyl,

propyl, butyl. amyl, and benzyl alcohols and that the colour of xanthate has no connection with

the alcohol radical which forms xanthate. It is proved that the colours of xanthates of alcohol and

cellulose are the same with respect to the same metal. But as the stability of xanthate decreases

with increasing molecular weight of alcohol radicals, the cellulose xanthate easily decomposes, and

the presence of sulphide and thiocarbonate affects the colour of pure cellulose xanthate. The colour

of pure cellulose xanthate was as follows :

Cu-Cellulose xanthate: yellow, Fe-Cellulose xanthate; brown, Co-Cellulose xanthate; dark green,

7.n_f Plln1es, xanthate: white. Pt-Cellulose xanthate; orange, etc.

The same consideration may be possible in case of the solubility and stability of alcohol and

cellulose xanthate. For example, aluminium alcoholic xanthate is more soluble and less stable than

the other trivalents alcoholic xanthates, so aluminium cellulose xanthate does not obey the

Hoffmeister's law in the coagulation of viscose.

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Summary.

1. The formation of xanthate with 48 kinds of the metallic elements and 6 kinds of

alcohols were studied.

2. The xanthates of metallic elements,. are formed directly from alcoholate of metals or

indirectly from the inter-reaction of sodium xanthates and metals.

3. The colour of xanthate is characterised by its salt but not by the sulfide of the metal,

existing in common.

4. When the molecular weight of alcohol which forms xanthate increases, the solubility of

xanthate in water decreases. If the xanthate radicals are the same, the larger the atomic weight

the easier the decomposition of the salt, forming sulfide.

5. The xanthates of metals are generally of the same colour, regardless of the alcohol radical

which forms xanthate.

6. Besides the reaction of copper, as the method of the detection of xanthate, the reaction

of cobalt is interesting.

7. The univalent alcoholic xanthates are insoluble in ether while the polivalent alcoholic

xanthates are soluble.

8. As the valeney of metal increases, the formation of xanthate becomes harder. With the

polivalent metals, the xanthate of the lowest valency are formed..

9. The colour of cellulose xanthate is the same with that of alcoholic xanthate with respect

to the same metal.

10. Cellulose xanthate sometimes does not obey the Hoffmeister's law. the cause of which is

ascribed to the stability and solubility of xanthate.

Department of Applied Chemistry. Faculty of Engineering. Tokyo Imperial University

Cellulose Research Laboratory. Faculty of Applied Chemistry, Tokyo Technical University College.