GB650493A - Manufacture of alkyl xanthogenate glycol formates - Google Patents

Abstract

Xanthate derivatives, termed alkyl xanthogenate glycol formates, are prepared by reacting one mol. of a glycol chloroformate containing two chloroformate radicals with at least one and not more than two mols. of an alkali metal alkyl xanthate. According to one method, an alkali metal alkyl xanthate is slurried in an inert organic liquid such as ether or benzene and the glycol chloroformate is added slowly at a low temperature, e.g. below 5 DEG C.; inorganic salts are then filtered off or leached out with water and the solvent distilled off. Alternatively, the xanthate is added directly to the chloroformate, preferably at below 40 DEG C., followed by washing or drying. In a third process, the chloroformate is added to a cold water solution of the xanthate at about 5 DEG C. and the product which separates out as an oil is removed and dried. Mixtures of xanthates may be used. The products, derived from diglycol chloroformate for illustrative purposes may have the general formula <FORM:0650493/IV (b)/1> or <FORM:0650493/IV (b)/2> where R=alkyl, depending on whether one or two mols. of xanthate are employed. The compounds may be used as flotation reagents, in which connection reference is made to Specification 650,498, [Group II]. In examples, the following compounds are interacted, using one or other of the above methods and in molecular proportions of xanthate to chloroformate of 1 : 1 or 2 : 1, (1) sodium ethyl xanthate, sodium sec.-butyl xanthate, sodium isopropyl xanthate and potassium amyl xanthate, respectively, with diglycol bis.-chloroformate; (2) sodium isopropyl xanthate, sodium ethyl xanthate and potassium amyl xanthate, respectively, with ethylene glycol bis-chloroformate; (3) sodium isopropyl xanthate with trimethylene glycol bis-chloroformate or dipropylene glycol bischloroformate; (4) sodium ethyl xanthate with octadecane diol bis-chloroformate (prepared by action of phosgene in carbon tetrachloride on the diol), triethylene glycol bis-chloroformate and butine-2-diol-1 : 4 bis-chloroformate, respectively. The Specification as open to inspection under Sect. 91 states that the glycol chloroformates may be reacted with at least one mol. of alkali metal xanthate. This subject-matter does not appear in the Specification as accepted.