Carbon Disulfide

CARBON DISULFIDE, CS₂, a colorless oily liquid with a characteristic odor; boils at 46°; very volatile; its vapors are 2.5 times heavier than air; almost insoluble in water, soluble in alcohol and ether. It is obtained by passing sulfur vapors over heated coal with subsequent condensation and collection under water. As a good solvent for fats, rubber, phosphorus, sulfur, etc., CS₂ finds application in a number of industries (e.g., in the production of artificial silk, in the rubber industry during cold vulcanization), in extracting fat from rags and bones, in the preparation of glue, as a disinfectant in the fight against phylloxera and ground squirrels, etc. Until a relatively recent time, CS₂ was one of the most dangerous industrial poisons in a number of industries, chiefly in rubber—giving a large number of very serious poisonings. In the last 30 years, due to its elimination from some industries or limitation of its use, as well as the adoption of safety measures, the number of CS₂ poisonings has decreased significantly, and the poisonings themselves are of a less severe character. In Italy in the last few years there were 100 cases, and in 80% of cases serious phenomena on the part of the nervous system were observed; in 1926 there appeared a report on one Polish artificial silk factory where during one year about 60 cases of very serious poisonings were registered. In the USSR in 1924–29 there were 54 cases of CS₂ poisoning; the predominant number refers to the chemical industry (artificial silk and rubber productions). CS₂ enters the organism in the form of vapors through the respiratory tract, as well as through the skin; about 90% of CS₂ is exhaled back. In Lehmans experiments on cats, concentrations above 2 mg per 1 liter of air caused the death of animals upon short-term action; at concentrations of 0.8–1.4 mg/l death occurred after two weeks. Data from a number of authors show that concentrations not exceeding 0.5 mg/l upon short-term exposure to humans already cause poisoning phenomena, a concentration of 0.15 mg/l upon action for a month can give phenomena of chronic poisoning. Picture of poisoning. Acute poisonings; see Poisoning. In workers inhaling for a long period small quantities of CS₂, toxic phenomena of varying severity develop on the part of the psyche and nervous system. In descriptions by Delpech (1853), there are indications of very severe psychic disorders. The number and severity of poisonings at present have decreased significantly, nevertheless even now in those constantly working with CS₂ phenomena on the part of the nervous system and psyche are often observed. In mild cases they are manifested by headaches, increased fatigue, apathy, weakness, vegetative disorders—bradycardia, dyspeptic phenomena, nausea, diarrhea, etc. In more severe cases more acute disorders of the psyche are noted: weakening of memory and attention, sometimes hallucinations of auditory and visual character, insomnia, psychic depression, alternating with psychic excitement, etc.; on the part of the nervous system—tremor of the extremities, very frequent peripheral polyneuritis on the extremities and face with muscular atrophies, muscular weakness, myalgias, disturbances of sensitivity, hyperesthesias and paresthesias, flaccidity of pupils and tendon reflexes, etc. In even more severe cases temporary and persistent psychoses of manic-depressive character may develop. Of 100 cases, Ranelletti (Italy) observed phenomena on the part of the nervous system in 80%, and in 52% of cases they were manifested by various psychoses, in 10%—neuritis, polyneuritis and paralysis. On the part of other organs, changes in the blood are described—anemia with lymphocytosis and basophilic granularity of erythrocytes, on the part of the digestive tract—functional and organic lesions of the stomach and intestines; as a result of long-term action of CS₂ a sharp cachexia may develop, etc. Pathological phenomena on the part of the central nervous system, blood and other organs upon cessation of contact with CS₂ are largely reversible, but very often the changes have a persistent character. At autopsy of animals that died from CS₂ poisoning, changes in the tissues of parenchymatous organs, chromatolysis of cells of the cerebral cortex, signs of inflammation of peripheral nerves, breakdown of myelin and other phenomena of damage to the nervous system are found. Prevention. The most radical practical measure for such a dangerous poison as CS₂ should be considered its complete elimination from production with replacement by other solvents or change of the production process (e.g., replacement of cold vulcanization by hot). It should however be borne in mind that such a replacement is not always possible and that sometimes instead of CS₂ solvents possessing no less toxicity are introduced (trichloroethylene, carbon tetrachloride, etc.). In the production of artificial silk, the main attention must be paid to the hermetic sealing of apparatus and proper ventilation of work premises with the aim of bringing the content of CS₂ in the air to negligible values. Further one can note the prohibition of adolescents to work with CS₂, periodic medical control, sanitary education of workers, etc.—TREATMENT—see Poisoning.

n. Rosenbaum. Detection in judicial cases and determination in occupational poisonings. The occasion for investigating internal organs, stomach contents, etc., for CS₂ is the characteristic odor and circumstances of the case. Parts of the internal organs are distilled with water vapor. A part of the distillate is heated on a water bath with an excess of alcoholic ammonia solution and then evaporated. In this process CS₂ gives ammonium thiocyanate. Addition upon weak acidification of a diluted solution of ferric chloride gives a red coloring (formation of ferric thiocyanate). A part of the distillate is mixed with an alcoholic solution of caustic potash (or sodium alkoxide). The liquid is weakly acidified with acetic acid and a drop of a solution of copper sulfide is added: a brown-black precipitate appears, which soon turns yellow. For the detection of CS₂ in the air, the latter is passed through absorbers with a solution of sodium alkoxide in alcohol and the reaction described above with copper sulfate is performed. For the quantitative determination of CS₂ in the air, a certain volume of air is drawn through a solution of alkoxide, after which the contents of the absorbers are poured into a measuring flask and brought to the mark with alcohol. A certain part of the liquid (e.g., 25 cm³) from the flask is diluted with water, acidified with diluted acetic acid, the excess of acid is removed by shaking with calcium carbonate, and, adding starch paste, it is titrated with 0.1 or 0.01 iodine solution.