Patent GB-425192-A (GB)
Title: Processes for the manufacture and application of unsaturated xanthates
IPC: C07C329/00
Filed: 1934-01-26
Abstract: Xanthates of unsaturated aliphatic monohydric alcohols containing a tertiary carbon atom, i.e. a carbon atom linked to three other carbon atoms, are prepared by treating the alcohols with carbon bisulphide and an alkali such as caustic soda, caustic potash, or ammonium hydroxide.  The reaction may be effected by adding an alkali solution to a mixture of the alcohol and carbon bisulphide in a vessel provided with a reflux condenser; an excess of alcohol or carbon bisulphide may be used, the vaporization of the excess serving to control the reaction temperature, or for the same purpose an inert liquid of suitable boiling point, e.g. propane, butane, pentane or their halogen derivatives, gasoline, benzene, or carbon tetrachloride may be added; a part or all of the alkali may be dissolved in or mixed with the alcohol and the remainder (if any) added as an aqueous solution, or solid alkali and water may be added separately; alternatively, an alkali alcoholate of the alcohol may be reacted with carbon bisulphide. Examples are given of the preparation of xanthates of isobutenol and of a mixture of isooctenols prepared by hydrolysis of monochlorodiisobutylenes.  Reference is made also to the preparation of xanthates of isocrotyl alcohol, isopropenylmethyl carbinol, isopentenyl alcohol of the formula CH2 : C(CH3) CH2CH2OH, and hexenyl and heptenyl alcohols containing a tertiary carbon atom. The xanthates are useful as promoters in flotation processes for treating ores, and for this purpose they may be used alone or with other promoters or the usual additions.  Examples are given in which a gold ore is concentrated by flotation with the aid of pine oil and isobutenyl or isooctenyl xanthate.  Copper, zinc, lead and similar ores may also be treated.  The xanthates are useful also as vulcanization accelerators and insecticides.  Isopentenyl alcohol of the formula given above is prepared by heating the corresponding chloride with aqueous caustic soda under pressure.  The chloride is obtainable by chlorinating the corresponding amylene.  The Specification as open to inspection under Sect. 91 states that the process may be applied to the preparation of xanthates of other unsaturated monohydric alcohols, and refers to the preparation of xanthates of allyl alcohol, pentenyl, hexenyl, heptenyl and octenyl alcohols in general, phenylisopropenyl carbinol, crotyl alcohol, and cyclohexenol.  It states also that these xanthates may be used for the purposes specified above. This subject-matter does not appear in the Specification as accepted.ALSO:Xanthates of unsaturated aliphatic monohydric alcohols containing a tertiary carbon atom, i.e. a carbon atom linked to three other carbon atoms, are stated to be useful as vulcanization accelerators.  Specified xanthates are those of isobutenol, mixed isooctenols prepared by hydrolysis of monochlorodiisobutylenes, isocrotyl alcohol, isopropenylmethyl carbinol, isopentenyl alcohol of the formula CH2:C(CH3) CH2CH2OH, and hexenyl and heptenyl alcohols containing a tertiary carbon atom.  The Specification as open to inspection under Sect. 91 states that xanthates of other unsaturated monohydric alcohols may also be used and refers to the use of xanthates of allyl alcohol, pentenyl, hexenyl, heptenyl and octenyl alcohols in general, phenylisopropenyl carbinol, crotyl alcohol, and cyclohexenol. This subject-matter does not appear in the Specification as accepted.ALSO:Xanthates of unsaturated aliphatic monohydric alcohols containing a tertiary carbon atom, i.e. a carbon atom linked to three other carbon atoms are used as promoters in flotation processes for treating ores. Specified xanthates are those of isobutenol, mixed isooctenols prepared by hydrolysis of monochlorodiisobutylenes, isocrotyl alcohol, isopropenylmethyl carbinol, isopentenyl alcohol of the formula CH2 : C(CH3)CH2CH2OH, and hexenyl and heptenyl alcohols containing a tertiary carbon atom.  The xanthates may be used alone or with other promoters or the usual additions. Examples are given in which a gold ore is concentrated by flotation with the aid of pine oil and isobutenyl or isooctenyl xanthate.  Copper, zinc, lead and similar ores may also be treated.  The Specification as open to inspection under Sect. 91 states that xanthates of other unsaturated monohydric alcohols may also be used, and refers to the use of xanthates of allyl alcohol, pentenyl, hexenyl, heptenyl and octenyl alcohols in general, phenylisopropenyl carbinol, crotyl alcohol, and cyclohexenol. This subject-matter does not appear in the Specification as accepted.