Carbon disulfide

Carbon disulfide
Image:Carbon-disulfide-structure.png Image:Carbon-disulfide-3D-vdW.png
Chemical name	Carbon disulfide
Other names	Dithiocarbonic anhydride
Chemical formula	CS2
SMILES	CS(S)
Molecular mass	76.1 g/mol
Appearance	colorless liquid impure: light-yellow
CAS number	75-15-0
Properties
Density	1.26 g/cm³
Melting point	-112 °C
Boiling point	46 °C
Solubility	0.2 g/100 ml of water (20 °C)
Hazards
Main hazards	Highly flammable CNS toxin
NFPA 704
Flash point	-30 °C
Autoignition temperature	90 °C
R/S statement	R: 12, 23, 24, 25 S:
Disclaimer and references

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Carbon disulfide is a colorless liquid with the formula CS₂. It has a pleasant odor that is like that of chloroform, although it is usually impure yellowish with an unpleasant odor like that of rotting radishes due to traces of other sulphurous species, such as carbonyl sulfide (COS).

[edit] Occurrence and manufacture

Small amounts of carbon disulfide are found in gases released by volcanic eruptions or marshes. CS₂ once was manufactured by combining carbon (or coke) and sulfur at high temperatures. A lower temperature reaction, requiring only 600 °C involves natural gas in the presence of kieselgel or alumina catalysts:

CH₄ + 1/2 S₈ → CS₂ + 2 H₂S

[edit] Chemical properties

CS₂ is structurally analogous to CO₂, but more reactive toward nucleophiles and bases and more easily reduced. This difference in reactivity can be attributed to the weaker π donor-ability of the sulfido centers.

[edit] Addition of nucleophiles

Nucleophiles such as amines afford dithiocarbamates:

2R₂NH + CS₂ → [R₂NH₂⁺][R₂NCS₂^-]

Xanthates form similarly from alkoxides:

RONa + CS₂ → [Na⁺][ROCS₂^-]

Sodium sulfide affords trithiocarbonate:

Na₂S + CS₂ → [Na⁺]₂[CS₃^2-]

[edit] Reduction

Sodium reduces CS₂ to give the heterocycle "dmit^2-"

3 CS₂ + 4 Na → Na₂C₃S₅ + Na₂S

Direct electrochemical reduction affords the tetrathiooxalate anion:

2 CS₂ + 2e → C₂S₄^2-

[edit] Other

Chlorination of CS₂ is the route to Thiophosgene.

CS₂ is a ligand for many metal complexes, forming pi complexes. One example is CpCo(η²-CS₂)(PMe₃)

It is used to manufacture regenerated cellulose (the main ingredient of viscose rayon and cellophane), carbon tetrachloride and organic sulfur compounds including those mentioned above. It is used as flotation agents in mineral processing, and Metham sodium soil fumigant.

[edit] Health effects

At very high levels, carbon disulfide may be life-threatening because it affects the nervous system. People who breathed carbon disulfide near an accident involving a derailed railroad car showed changes in breathing and some chest pains, although these effects are probably due to the sulfur oxides formed in the ensuing fire.

Some workers who breathed high levels during working hours for at least 6 months had headaches, tiredness, and trouble sleeping, in some cases even serious central and peripheral nervous system disease such as toxic encephalitis and peripheral mixed neuropathy. Most of these data come from the Viscose rayon Industry, where small amounts of H₂S may also have been present. Among workers who breathed lower levels, some developed very slight changes in their nerves. An increased risk of cardiovascular death has also been established in several countries.

Studies in animals indicate that carbon disulfide can affect the normal functions of the brain, liver, and heart. After pregnant rats breathed carbon disulfide in the air, some of the newborn rats died or had birth defects.

Liquid carbon disulfide has caused skin burns.

[edit] External links

• National Pollutant Inventory - Carbon disulfide

• Link page to external chemical sources.

[edit] References

• Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
• Werner, H. "Novel Coordination Compounds formed from CS₂ and Heteroallenes" Journal of Organometallic Chemistry, 1982, volume 43, pages 165-185.cs:Sirouhlík

de:Kohlenstoffdisulfid es:Disulfuro de carbono lv:Sērogleklis nl:Koolstofdisulfide ja:二硫化炭素 pl:Dwusiarczek węgla fi:Hiilidisulfidi sv:Koldisulfid tr:Karbondisülfür zh:二硫化碳 ru:Сероуглерод

Categories: Sulfides | Inorganic carbon compounds | Solvents