Preparation of Xanthates

But someone proposed that the reaction can be given by the following  

Based on the testing of as labeled atom, it displayed that the O atom of NaOH entered into H2O, with the O atom of ROH entering into the synthetical xanthates. 

The content of the active ingredient of xanthate is usually about 79-82 % in China. The quality guarantee period of xanthate is generally half-year. The technological parameter for the preparation of xanthates varies with experiment condition. Based on reports, the main technological parameters for various sodium xanthates can be given as follows  

Meantime, some side reactions occur during the preparation of xanthates. 

CS2 -h 2NaOH NaOCSSNa + H2O NaOCSSNa + 2H2O 2NaHS + H2CO3 

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Another, quite different procedure is the preparation of xanthates from ethers (69) ... 

Alcohols can be dehydrated via xanthate esters at temperatures that are much lower than those required for acetate pyrolysis. The preparation of xanthate esters involves reaction of the alkoxide with carbon disulfide. The resulting salt is alkylated with methyl iodide. 

The method is comparable to the xanthate method4 but has certain advantages. The preparation of xanthates requires two steps reaction of the alkoxide with carboA disulfide followed by alkylation. Yields of olefins by the present method are at least as high as and sometimes higher than those obtained from xanthates. 

General directions for preparation of xanthates 755 Finely powdered potassium hydroxide (56 g, 1 mole) is dissolved in the requisite amount of an alcohol, the solution is cooled to room temperature, and carbon disulfide (76 g, 1 mole) is added with stirring during 30 min. After a further hour s stirring, ether is added to complete the precipitation of the xanthate, which is then filtered off and recrystallized from ethanol. Yields are 80-95 %. 

A colourless highly refractive liquid, CS2, slightly soluble in water and soluble in ethanol and ether r.d. 1.261 m.p. -110°C b.p. 46.3°C. Pure carbon disulphide has an ethereal odour but the commercial product is contaminated with a variety of other sulphur compounds and has a most unpleasant smeU. It was previously manufactured by heating a mixture of wood, sulphur, and charcoal modern processes use natural gas and sulphur. Carbon disulphide is an excellent solvent for oils, waxes, rubber, sulphur, and phosphorus, but its use is decreasing because of its high toxicity and its flammability. It is used for the preparation of xanthates in the manufacture of viscose yarns. 

Comparatively speaking, the preparation of xanthate ester is simple. For example, xanthate ester can be produced by adopting xanthate and chloroalkene as feeds. And cyanate ester can be produced by adopting xanthate and vinyl cyanide as feeds. The related reactions are as follows ... 

In a study of the influence of temperature (30—45°C) on the preparation of isopropyl xanthates, it was determined that increa sing the temperature resulted ia a decrease ia the xanthate yield and an iacrease ia by-products. Also, a decrease ia the water content of the alcohol iacreases the xanthate yield (70). 

A modified and detailed procedure is given for the preparation of the corresponding, and Co " xanthates ia good yields and high purity (18). A... 

The most important hazard ia the manufacturiag of xanthates is the use of carbon disulfide (qv) because of its low flash poiat, ignition temperature, and its toxicity. A report on the manufacture of sodium ethyl xanthate at Keimecott Nevada Mines Division discusses the various safety problems and the design of a faciUty (81). A plant layout and a description of the reagent preparations are also given. 

Of great commercial significance is preparation of sodium ceUulose xanthate [9032-37-5] solution (viscose) by reaction with alkaH ceUulose ... 

The described method of preparation of w-nitrophenyl disulfide is essentially that of Foss and co-workers and is a modification of that reported by Ekbom. The disulfide has been prepared by reaction of potassium ethyl xanthate with w-nitrobenzenedi-azonium chloride solution, followed by hydrolysis to yield the mercaptan, which is subsequently oxidized with potassium ferro-cyanide or dilute nitric acid to the disulfide. ... 

Carbonates and carbamates are reported to be intermediate in stability and easier to prepare than xanthates. " They can conveniently be prepared directly from the alcohol in high yield and give clean conversion to olefins. Cholesta-3,5-diene, for example, can be readily obtained via the phenylcar-bamate (114) or ethylcarbonate (115) of cholesterol. Such esters appear to have been somewhat neglected as synthetic intermediates. 

Diazonium xanthates (ArN—NSCSOC2H5) can detonate, and this procedure should be followed carefully to ensure decomposition of the xanthate as it is formed. Under no circumstances should the diazonium solution and the potassium ethyl xanthate be mixed cold and the mixture subsequently heated. A severe detonation has been reported when such a procedure was employed during the preparation of thiocresol. 

Nickel catalyst, Raney, in preparation of 2,2 bipvndine, 46, 5 VV7 J, preparation of, 46, 5 Nickel ion, as catalyst for decomposition of diazomum xanthates, 47,... 

Dining preparation of thiophenol by addition of a cold solution of potassium O-methyldithiocarbonate to a cold solution of benzenediazonium chloride, a violent explosion accompanied by an orange flash occurred [1], This was attributed to the formation and decomposition of bis(benzenediazo) disulfide. A preparation in which the diazonium solution was added to the xanthate solution proceeded smoothly [2],... 

There is an enormous literature on thiocarbonyl compounds, due in part to the technical and industrial importance of many of them, including thioamides, thioureas, xanthates, dithiocarbamates and so forth. An excellent, and recent, general review is available.107 There are also specialized reviews germane to the present chapter Griffin, Woods, and Klayman2 discussed the use of thioureas in the synthesis of heterocycles the preparation of thiazoles from thioamides is included in a three-part volume on Thiazoles 108 the use of carbon disulfide in the synthesis of trithiones and related heterocycles has been reviewed by Mayer109 and Huisgen110 has reported numerous examples of 1,3-dipolar cycloadditions in which carbon disulfide was used. 

Based on the encouraging results obtained from laboratory testing, a plant test was conducted at the Kolwezi concentrator, during which a number of important factors in preparation of the fatty acid xanthate emulsion were discovered, some of which included ... 

The best results were obtained using collector DAS-2, consisting of xanthated fatty acid + amine. The reagent was prepared by ultrasonic agitation of xanthate (50%), fatty acid (25%) and amine (25%). The mixture is a yellow-coloured solution. 

Because of the strong hydrolysis property of antimony salt, it is very difficult to prepare antimony xanthate salt to obtain its IR spectrums. Therefore, the formation of antimony xanthate is difficult to be identified by the UV and FTIR analysis, which has been determined by using XPS. Finally, it can be concluded that the interaction mechanism between ethyl xanthate and jamesonite are attributed to the formation of lead and antimony xanthate on the surface in the light of flotation results, voltammogram measurement, UV and FTIR as well as XPS analyses. 

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