Carbon disulfide is a colorless volatile liquid with the formula CS2, useful as a non-polar solvent.
Chlorination of CS2 yields carbon tetrachloride and sulfur dichloride:
- CS2 + 3 Cl2 → CCl4 + S2Cl2
Carbon disulfide is a colorless liquid, with an chloroform like smell when pure. Impure CS2 has a yellowish color and has a putrid smell. It is insoluble in water, but soluble in many organic solvents, such as benzene, ethanol, diethyl ether, carbon tetrachloride, chloroform. It's poorly soluble in formic acid. CS2 boils at 46.24 °C and freezes at −111.61 °C. It has a low autoignition temperature for a solvent, of only 102 °C.
Carbon disulfide is sold by chemical suppliers, however there appears to be no sellers on Ebay or Amazon. It is a hard to find reagent.
There are many ways to synthesize CS2, most if not all tend to produce plenty of side products, which means that the product will be impure and have a bad smell. Some processes have low yield.
The first method, involves the reaction of sulfur vapors with carbon (or coke, anthracite, or any other coal) at 900°C. The resulting vapors are condensed and sulfur disulfide is purified. BromicAcid managed to synthesize only a few ml using this method. A few years later, garagechemist in collaboration with Len1, tried to improve the said method, using a tube furnace. It yielded around 44 g of CS2. myst32YT mas also made a small amount of carbon disulfide.
Another method, that works at lower temperatures (600 °C), utilizes methane as the carbon source in the presence of silica gel or alumina catalysts:
- 2 CH4 + S8 → 2 CS2 + 4 H2S
The thermal decomposition of ammonium thiocyanate, preferably in an inert atmosphere yields carbon disulfide, ammonia, hydrogen sulfide, leaving a residue of guanidinium thiocyanate. This reaction produces a fairly pure compound, though the starting products are not particularly cheap. Other thiocyanates can also be used. An approximate reaction of the decomposition is shown below:
- NH4SCN → CS2 + NH3 + H2S + CH6N3SCN
A different way involves the reaction of carbon monoxide with sulfur, in the presence of a catalyst such as iron, iron(III) sulfide, at temperatures between 400 - 500 °C. The same reaction can also be carried out at 500 °C in the presence of silica gel.
Carbon disulfide can also be obtained in traces by reacting benzene with sulfur dioxide, at 500°C. It also produces many byproducts,such as dithiobenzene, carbon dioxide, carbonyl sulfide, some free oxygen, and some unknown polymeric residue. The reaction can be improved by using a vanadium pentoxide/alumina catalyst, the reaction taking place at 1000-1200 °C.
Pyrolysis of scrap tires also gives carbon disulfide, although separating it from the mixture is not very practical.
- Sulfur extraction and purification
- Barking dog reaction
- Make carbon tetrachloride
- Make sulfur disulfide
- Make KS Fluid
- Solvent for synthesis of phosphorus triiodide
- Synthesize trithiocarbonates
- Prepare xanthate salts
Carbon disulfide has moderate toxicity. It is an irritant to the eyes and skin. CS2 is however extremely volatile and flammable.
Carbon disulfide should be stored in closed bottles away from any heat source. Due to it's high volatility its best kept in a cold place. The bottle should be open periodically to prevent a pressure build-up.
Carbon disulfide can be burned, although this will produce sulfur dioxide gas.
- Fomin, W. A., Zhurnal Obshchei Khimii, 1936, Vol. 6, p. 852 - 854
- Bulletin de la Societe Chimique de France, 1908, Vol. <4> 3, p. 151
- DE398322 C
- Moissan, Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences (1894), Vol. 118, p. 502