GB781905A - Improvements in the production of organic tin compounds - Google Patents

Abstract

Synthetic resins (e.g. halogen-containing polyvinyl compounds and their copolymers) and halogenated synthetic rubbers (e.g. from condensed chlorbutadiene) may be stabilized against ageing by addition of an organotin compound of formula <FORM:0781905/IV (a)/1> where X1 and X2 are alkyl groups, Y is the residue of an alcohol or a carboxylic acid and Z is the residue of a saturated or unsaturated aliphatic or cycloaliphatic compound containing one or more mercapto groups. Compounds specified include dodecyl mercapto dibutyl tin laurate, dodecyl mercapto dibutyl tin oleate, dodecyl mercapto dibutyl tin methyl maleate: <FORM:0781905/IV (a)/2> and many others.ALSO:The invention comprises organo tin compounds of formula <FORM:0781905/IV (a)/1> where X1 and X2 are identical or different alkyl groups, Y is the residue of an alcohol or carboxylic acid and Z is the residue of a saturated or unsaturated aliphatic or cycloaliphatic compound containing one or more mercapto groups. They may be prepared by reacting a dialkyl tin dihalide of formula X1X2SnHal2 simultaneously or in any sequence with such amounts of an alkali metal compound of an alcohol or carboxylic acid and a saturated or unsaturated aliphatic or cycloaliphatic compound containing one or more mercapto groups that the resultant product contains equivalent amounts of the alcohol or carboxylic acid and the mercapto compound. Specified dialkyl tin dihalides include dimethyl, diethyl, dipropyl, dibutyl, diamyl, dihexyl, dioctyl, diallyl, methylethyl, methylbutyl, ethylbutyl tin dichloride, dibromide and di-iodide. Suitable alcohols specified include methanol, ethanol, propanol, butanol, hexanol, octanol, ethylhexanol, dodecanol, allyl alcohol, cyclohexanol, benzyl alcohol, tetrahydrofuryl alcohol and the ether or thioether alcohols derived therefrom. Acetic, propionic, butyric, valeric, caproic, ethylhexanoic, pelargonic, palmitic, acrylic, crotonic, linoleic, lauric, oleic, ricinoleic, benzoic, cinamic, and phenylacetic acids are specified as carboxylic acids. There may also be used the half esters of dicarboxylic acids, e.g. maleic, succinic, adipic and phthalic acid. Compounds containing mercapto groups (used as their metal, especially alkali-metal derivatives) include methyl, ethyl, propyl, n-butyl, iso-butyl, ethylhexyl, octyl, decyl, dodecyl, octadecyl, allyl, cyclohexyl, methylcyclohexyl and cyclopentyl thiols. The hydrocarbon chains or rings may be interrupted by oxygen or sulphur atoms, sulphoxy, sulphonyl or imido groups or also contain carbonyl or epoxidic oxygen, e.g. mercapto dibutyl ether, 4,41-dimercapto dibutyl ether, and the corresponding thioethers. These compounds may also contain halogen or further mercapto groups, e.g. 1,2-dimercapto ethane, 1,3-dimercaptopropane, 1,4-dimercaptobutane, 1,4-dimercapto-2,3-dichlorbutane. Saturated or unsaturated monobasic or dibasic thiolic acids, e.g. acetothiolic acid, dithioacetic and, thiobutyric acid, dithiobutyric acid, dithiomalonic acid, dithioadipic acid, thioacrylic acid and thiocrotonic acid may also be used. The reaction may be carried out between - 10 DEG C. and 150 DEG C., preferably in inert solvents such as benzene, toluene or xylene. The alcoholic starting material may be used in excess as diluent. In an example dodecyl mercaptan dissolved in benzene is added to a solution of sodium methylate in methanol. To the mixture lauric acid in benzene is added, and the whole stirred for half an hour. Dibutyl tin dichloride in benzene is then added and the mixture refluxed. Sodium chloride precipitates on cooling and is filtered off. The solvent is distilled from the filtrate under reduced pressure and the tin compound purified by solution in toluene, addition of animal charcoal, filtration and removal of the toluene. Among other compounds prepared are dodecylmercapto dibutyl tin oleate and dodecylmercapto dibutyl tin methyl maleate: <FORM:0781905/IV (a)/2> Specifications 692,556, 719,733 and 781,906, [Group IV (a)], are referred to.ALSO:Organotin compounds of formula: <FORM:0781905/V/1> where X1 and X2 are alkyl groups, Y is the residue of an alcohol or a carboxylic acid and Z is the residue of a saturated or unsaturated aliphatic or cycloaliphatic compound containing one or more mercapto groups may be used as rubber antioxidants. Compounds specified include dodecylmercapto dibutyltin laurate, dodecylmercapto dibutyl tin oleate, dodecylmercapto dibutylt in methyl maleate: <FORM:0781905/V/2> and many others.