CARBON DISULPHIDE, carbon bisulphide or thiocar bonic anhydride, a chemical product first discovered in 1796 by W. A. Lampadius, who obtained it by heating a mixture of char coal and pyrites. Carbon disulphide, may be more con veniently prepared by passing the vapour of sulphur over red hot charcoal, the uncondensed gases so produced being led into a tower containing plates over which a vegetable oil is allowed to flow in order to absorb any carbon disulphide vapour, and then into a second tower containing lime, which absorbs any sulphuretted hydrogen. The crude product is very impure and possesses an offensive smell ; it may be purified by forcing a fine spray of lime water through the liquid until the escaping water is quite clear, the washed disulphide being then mixed with a little colourless fat and distilled at a low temperature. Carbon disulphide is manufactured on a considerable scale. An electric furnace built of fire-proof stone is heated by four insulated electrodes situated in the base of the hearth; the shaft is filled from above with charcoal, the sulphur is introduced at the side of the hearth and passes in a molten state through annular canals into the reaction zone, where it is vaporized into the charcoal mass. The crude product is purified by treatment with milk of lime and vegetable fats and by repeated distillation. Final purification for chemical purposes is effected by distillation over mercury and by drying over calcium chloride.
When quite pure, carbon disulphide is a colourless, somewhat pleasant smelling, highly refractive liquid, of specific gravity 1.2661 (18°/4°) (J. W. Briihl) or 1.29215 (T. E. Thorpe). As generally met, however, it has a fetid odour, owing to the pres ence of small quantities of powerfully evil-smelling organic sul phur compounds. It boils at 46.25° C. and solidifies at — I 16° C., melting at 113° C. Its critical temperature is 277.7° C., and its critical pressure is 78•1 atmos. It is very volatile, the vapour being heavy and dangerously inflammable. It burns with a pale blue flame to form carbon dioxide and sulphur dioxide, this change being also produced by oxidizing agents. It is almost insoluble in water, but mixes in all proportions with absolute alcohol, ether, benzene and various oils. It is a good solvent for sulphur, phos phorus, iodine, waxes, vegetable and animal fats and oils. A mix ture of carbon disulphide vapour and nitric oxide burns with a very intense blue-coloured flame, which, being very rich in the violet or actinic rays, is sometimes employed photographically. Zinc and hydrochloric acid reduce it to tri-thioformaldehyde When treated with chlorine in presence of an iron catalyst it yields carbon tetrachloride and sulphur chloride, and when passed over sodamide it yields ammonium thiocyanate. A mixture of carbon disulphide vapour and sulphuretted hydrogen, when passed over heated copper produces methane.
By the action of aqueous alkalis, carbon disulphide is converted into a mixture of an alkaline carbonate and an alkaline thiocar bonate, = K2CO3 2K2CS3+3H20; alcoholic caustic alkali, on the other hand, converts it into a xanthate, Carbon disulphide is used in the manufacture of viscose (artificial silk), as a solvent for oils, fats, resins and caoutchouc, as a germi cide, and as an insecticide. It is also the starting point in the manufacture of carbon tetrachloride, ammonium thiocyanate, thio urea and thiourea formaldehyde resins.
Carbon monosulphide, CS, is formed when a silent electric dis charge is passed through a mixture of carbon disulphide vapour and hydrogen or carbon monoxide. A polymerized form (CS)x is obtained by the action of nickel carbonyl on thiocarbonyl chloride.
Carbon subsulphide, a red liquid, is produced by striking an electric arc under carbon disulphide between a carbon cathode and a carbon—antimony anode.