Carbon disulphide, from decomposition

V,/V-Disubstituted thioformamides, R1R2NCH=S, are obtained from primary or secondary amines and dimethylthioformamide at 110°C. Aromatic amines do not react for electronic reasons nor does A-methylcyclohexylamine because of steric hindrance323. Decomposition of carbon disulphide in a high-voltage discharge gives CS, which reacts... 

At 800° C. reaction (2) appears to proceed slowly in either direction, while (1) is very rapid. The fact that the degree of dissociation in (1) is. independent of the amounts of carbon dioxide and carbon disulphide present, shows that carbon monoxide and sulphur are primary products of the decomposition of carbonyl sulphide and are not formed secondarily from the carbon dioxide and carbon disulphide. At temperatures below 400° C. decomposition according to equation (1) is not evident, while at 900° C. it reaches a maximum (64 per cent.) reaction (2) reaches a maximum at about 600° C., at which point 43 per cent, of the carbonyl sulphide is decomposed in this way and 16 per cent, according to reaction (1). The carbon monoxide equilibrium depends upon the pressure, whilst the carbon dioxide equilibrium does not. Nearly all the reactions involved in the thermal decomposition of carbonyl sulphide depend greatly on catalytic influences. Quartz is a pronounced catalyst for reaction (2), but has little influence on reaction (1). Carbonyl sulphide is comparatively rapidly decomposed in quartz vessels, but is stable when kept in glass apparatus. The viscosity of gaseous carbonyl sulphide is as follows x... 

The monochloride is soluble in various inert organic liquids, more particularly in benzene, chloroform, carbon tetrachloride and carbon disulphide, without undergoing chemical change. It is an exothermic compound, its heat of formation from gaseous chlorine and the amorphous modification of selenium being 22-1 Cals.1 Water causes a gradual decomposition of the chloride, selenium dioxide and selenium being formed 2... 

Although stable in dry air, the tetrachloride is gradually decomposed by moisture it deliquesces, giving an oxychloride. This oxychloride is probably only a mixture of tetrachloride and dioxide.3 With a larger quantity of water the tetrachloride dissolves, giving rise finally to tellurium dioxide. It is soluble without decomposition in aqueous hydrochloric acid (from which an unstable compound HCl.TeCl4.5H20 crystallises at —30° C.), also in carbon disulphide and sulphur monochloride.4... 

Arsenic Pentiodide ( ), Asls.—When a mixture of arsenic and iodine in the requisite proportions is heated in an atmosphere of carbon dioxide in a sealed tube at 150° C., a brown crystalline product is obtained.3 The crystals, which melt at 70° C. and have density 3-93, are soluble in water, carbon disulphide, alcohol, ether and chloroform. The solution in carbon disulphide yields, when allowed to crystallise, a mixture of arsenic triiodide and iodine. The latter is readily lost from the pentiodide, and heating at 100° C. in nitrogen in a sealed tube brings about the decomposition. Like the triiodide, the pentiodide dissolves boron tribromide.4... 

Di-a-naphthyl selenium dibromide, (C10H7)2SeBr2, is prepared in the usual manner. It forms wThite needles, melting at 183° C. with decomposition, soluble in amyl alcohol but best recrystallised from carbon disulphide. The halogen may be removed by alkali, but only di-a-naphthyl selenide results, no selenoxide being isolated as in the preceding cases. 

The melting-point of the commercial sulphide was 255° C.2 and that of the recrystallised product 275° to 276° C.3 The melting-point was raised to 284° to 291° C. by repeated recrystallisation from carbon disulphide.4 Boiling occurs with partial decomposition at 513° to 515° C.4 Other values which have been found are 520° C.,5 523-6° C.e The sulphide distils in a water-pump vacuum at 332° to 340° C., probably with considerable dissociation (see Vapour Density ).7... 

Natural waters may be contaminated with carbon disulphide and hydrogen sulphide from wastewaters from the chemical industry and more frequently by hydrogen sulphide formed during the anaerobic decomposition of organic matter. 

When cellulose is treated with carbon disulphide and sodium hydroxide, a cellulose xanthate is formed. This salt when stirred with a small amount of water forms a thick solution, called viscose, which is converted into cellulose hydrate by heat or certain salts. By squirting viscose through capillary tubes into a solution which brings about this decomposition, threads of cellulose are obtained having a silky luster. From these artificial silk is made. Viscose is also used for paper-sizing, in textile printing, and as a cement. 

---