Carbon Disulfide
Properties
| State | Liquid (colorless to pale yellow, volatile, with sweet odor when pure) |
| Color | Colorless (pure); pale yellow (commercial grade) |
| Solubility | Slightly soluble in water (2.2 g/L at 20°C); miscible with ethanol, ether, benzene, and chloroform |
| Melting Point | -111°C |
| Boiling Point | 46°C |
About Carbon Disulfide
Carbon disulfide is the sulfur analog of CO2 — same linear S=C=S geometry, sp-hybridized carbon, zero molecular dipole — but the chemistry could not be more different. Where CO2 sublimes at −78.5 °C, CS2 is a volatile liquid (bp 46 °C) because the larger, more polarizable sulfur atoms throw far stronger London dispersion forces between molecules. CS2 has a flash point of −30 °C and an autoignition temperature of just 90 °C, lower than any other common solvent — a hot steam pipe is enough to ignite the vapor — which is why every safety induction for CS2 work emphasizes that there are essentially no acceptable ignition sources in the same room. As a solvent, CS2 dissolves elemental sulfur and white phosphorus better than almost anything else, which makes it indispensable when those allotropes need to be handled in solution. Its largest industrial use, however, is the viscose process: alkali cellulose (wood pulp slurried in NaOH) reacts with CS2 to form sodium cellulose xanthate, which is dissolved in dilute caustic to give the orange viscose dope, then extruded through a spinneret into an acid bath where the xanthate hydrolyzes back to cellulose as rayon fiber. World rayon production still consumes hundreds of thousands of tonnes of CS2 per year. CS2 is also the precursor for dithiocarbamate fungicides — maneb, mancozeb, ziram — made by reaction with primary amines and base, and it is the historical route to CCl4 and tetraethylthiuram disulfide (Antabuse). The catch is severe neurotoxicity: chronic exposure causes peripheral neuropathy, parkinsonism, and accelerated atherosclerosis, and the viscose industry has the documented occupational-disease history to prove it.
Where you'll encounter it
Every viscose rayon plant in the world is essentially a CS2 facility, and the orange-yellow tint of fresh viscose dope on a textile floor is unmistakable. In an organic teaching lab, the small bottle of CS2 in the flammables cabinet is what you reach for when you need to dissolve a few hundred milligrams of S8 for a sulfur transfer reaction or a bromonium-ion trapping experiment, and you handle it in a fume hood with no hot plates running and the bench cleared of friable material. In rubber chemistry, CS2 is the synthetic root of the entire dithiocarbamate accelerator family that makes tire vulcanization possible at industrial scale. Pure CS2 has a sweet, ethereal odor — almost pleasant — but technical grades stink of carbonyl sulfide and H2S impurities, which is the warning that something has gone off.
Common Uses
- Cellulose xanthate intermediate in viscose rayon and cellophane manufacture (largest single use)
- Solvent for elemental sulfur and white phosphorus in laboratory work
- Synthesis of dithiocarbamate fungicides (maneb, mancozeb, ziram) and rubber accelerators
- Precursor for carbon tetrachloride and tetraethylthiuram disulfide (Antabuse)
- Flotation collector in nonferrous mining for differential separation of sulfide ores
Safety Information
Extreme fire hazard: flash point −30 °C, autoignition 90 °C, explosive limits 1 to 50 percent in air — among the widest of any common solvent. Vapors are 2.6 times denser than air and pool at floor level. Treat steam pipes, light bulbs, and electrical contacts as ignition sources. Chronic neurotoxicity is the dominant occupational concern: ACGIH TLV-TWA 1 ppm, OSHA PEL 20 ppm (8-hour TWA), with documented peripheral neuropathy, parkinsonism, accelerated atherosclerosis, and reproductive toxicity from long-term low-level exposure in viscose-rayon workers. GHS: H225 (extremely flammable), H315/H319/H336, H361 (reproductive toxicity Cat. 2), H372 (target-organ toxicity, repeated exposure). Use only in a hood with explosion-rated equipment.
This safety summary is for educational reference only and may not be complete. It is not a substitute for Safety Data Sheets (SDS), medical advice, or professional chemical safety guidance. Always consult appropriate SDS and qualified professionals before handling chemicals.