Xanthates


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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.

V. N. FROSIN

References in periodicals archive ?
Sankararamakrishnan, "Highly enhanced adsorption for decontamination of lead ions from battery wastewaters using chitosan functionalized with xanthate," Bioresource Technology, vol.
When sodium ethyl xanthate, a more aggressive collector was tried, the pyrite was floated as well in addition to sphalerite.
Saboury, "A calorimetric investigation for the bindings of mushroom tyrosinase to p-phenylene-bis dithiocarbamate and xanthates," Journal of the Serbian Chemical Society, vol.
Metal xanthates are known to decompose beyond these limits [36].
The wide range of sulphhydril collectors consists of high quality xanthates and Hostaflot[R] grades (aliphatic dithiophosphates and thiocarbamates).
This article will discuss xanthate accelerators in vulcanization systems for isobutylene-based elastomers.
Expecting relatively minor changes in standard mechanical cell design or in slightly modifying existing reagents such as xanthates, thionocarbamates, dithiophosphates, etc.
Thiols, thiones and xanthates are typical examples.
Depending on the cure system, thiurams, dithiocarbamates and xanthates may show poor reversion resistance.