Carbonyl sulphide, decomposition

Some thiocarbonates yield carbonyl sulphide on decomposition, thus 2... 

An important method of preparing carbonyl sulphide consists in the decomposition of a thiocyanate with moderately concentrated (14-/V) sulphuric acid, the liberated thiocyanic acid being hydrolysed thus ... 

Properties.—Pure carbonyl sulphide is a colourless, odourless gas, which is slowly decomposed by water. When dry it is stable, even in sunlight, and if kept over sulphuric acid it undergoes only slight decomposition. Its density at —87° C. is 1-24. It melts at —138-2° C. and boils at -50-2° C. under a pressure of 760 mm.4... 

The thermal decomposition of carbonyl sulphide has been investigated.5 The products of dissociation may be carbon monoxide and... 

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 thiocyanates, except those of the heavy metals, are decomposed in the cold by dilute mineral acids, and on heating, the free thiocyanic acid distils over. With moderately concentrated acid, carbonyl sulphide is produced (see p. 270), whilst concentrated sulphuric acid causes rapid decomposition, with evolution of pungent vapours containing carbonyl sulphide, formic acid, carbon dioxide and sulphur dioxide. 

TABLE VIII - Influence of the Continuous Addition of Either Hydrogen Sulphide. Sulphur Dioxide or Carbonyl Sulphide to the Gas Phase upon Carbon Deposition f ran Acetone Decomposition on FeiO/. at 600°C... 

DECOMPOSITION OF INORGANIC OXIDES AND SULPHIDES HALIDES AND DERIVATIVES METAL ALKYLS, ARYLS, CARBONYLS AND NITROSYLS... 

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