Xanthates

derivatives (salts and esters) of xanthic acids

where R is a hydrocarbon radical and R’ is a metal (salts) or a hydrocarbon radical (esters).

Xanthates (salts), unlike xanthic acids [acidic esters of dithio-carbonic acid ROC(=S)SH], are stable compounds. The xanthates of alkali metals disolve readily in water. They are generally prepared by the interaction of carbon disulfide and alcohol in the presence of an anhydrous alkali:

CS₂ + ROH + NaOH → ROCSSNa

Xanthates (esters)—full esters of dithiocarbonic acid—can be obtained by alkylation:

ROCSSK + R’l → ROCSSR’ + KI

Xanthates (esters) decompose upon heating into mercaptan, car-bonyl sulfide, and an unsaturated hydrocarbon (Chugaev reaction), for example:

C₂H₅O—CSSCH₃→ CH₃SH + COS + CH₂=CH₂

The most valuable xanthate, cellulose xanthate, is used in the manufacture of viscose fiber. Certain xanthates (salts) are used in the flotation of sulfide ores and in the preparation of insecticides. They also serve as accelerators in the vulcanization of rubber and as preparations for the analytical determination of molybdenum.