GB727257A - Improvements in or relating to method of preparing alkali metal xanthates - Google Patents

Abstract

A process for preparing alkali metal xanthates comprises preparing a dispersion of an alkali metal alcoholate by treating an alkyl alcohol with an alkali metal hydroxide at a temperature of from 70 DEG to 100 DEG C. in a liquid organic medium that is inert to the alkali metal alcoholate and to carbon disulphide, said medium being present in a volume of from about 16 to about 36 times that of the solid metal hydroxide and containing a maximum of one mol. of water for each mol. of alkali metal hydroxide, cooling the reaction mixture below the boiling-point of carbon disulphide, and reacting carbon disulphide with the dispersed alkali metal alcoholate, whereby substantially pure alkali metal xanthate is formed. The liquid organic medium may be an excess of the alcohol, in which case preferably not more than 10 mols. of alcohol per mol. of hydroxide are used, or may be a solvent for the alcohol. The reaction with the carbon disulphide can be effected at 30 DEG to 45 DEG C. As alkali metal hydroxides lithium, sodium, potassium, rubidium and caesium hydroxides are specified. Methyl, ethyl, isopropyl and sec.-butyl alcohols are referred to. Suitable inert solvents are toluene, isopropyl ether, heptane and gasoline. Some water may be present in the alcohol as long as the total water present does not exceed two mols. per mol. of xanthate to be prepared. In examples: (1) sodium hydroxide containing 25 per cent by weight of water is melted, reacted with excess isopropyl alcohol, and the slurry of alcoholate, after cooling, is reacted with carbon bisulphide at 45 DEG C.; (2) in a process similar to (1), reaction is effected at 30 DEG C.; (3) toluene is employed as the medium in reacting the molten sodium hydroxide with isopropyl alcohol and the slurry is thinned by adding acetone before the reaction with carbon bisulphide. Further examples, similar to (3) illustrate the use as inert media of (4) heptane, (5) gasoline, (6) isopropyl ether and heptane, (7) and (8) isopropyl ether and toluene.