GB756483A - Production of esters of gamma-ketopimelic acid - Google Patents

Abstract

Esters of a -ketopimelic acid of the general formula RO.OC.CH2.CH2.CO.CH2.CH2.CO.OR, in which each R is an alkyl or cycloalkyl group containing from 4 to 12 carbon atoms or a b -alkoxyethyl group in which the alkoxy group contains from 1 to 8 carbon atoms, (see Group IV (b)), are used as plasticizers for polyvinyl chloride resins and copolymers containing vinyl chloride with vinyl acetate, vinylidine chloride, dimethyl maleate, dimethyl fumarate or methyl methacrylate. Specific compositions mentioned contain polyvinyl chloride, an ester of g -ketopimelic acid, e.g. dicapryl g -ketopimelate or di-(2-ethylhexyl)-g -ketopimelate, and a basic lead silicate stabilizer. The plasticized polyvinyl chloride compositions find use in calendered films, sheeting for wearing apparel, shower curtains, seat and cushion covering and extruded insulation for electrical wiring.ALSO:Esters of g -ketopimelic acid of the general formula RO.OC.CH2.CH2.CO.CH2CH2.CO.OR, in which each R is an alkyl or cycloalkyl group having 4 to 12 carbon atoms or a b -alkoxyethyl group in which the alkoxy group has 1 to 8 carbon atoms, are prepared by heating g -pimelic acid dilactone with at least two molecular proportions of an alcohol ROH, in which R is as above defined, in the presence of an acid esterification catalyst, such as sulphuric acid, benzene sulphonic acid or a toluene sulphonic acid. The reaction temperature is normally from 100 DEG to 175 DEG C., and water of esterification is removed during the reaction by distillation. A water entrainer such as butanol, benzene, toluene, xylene, chlorobenzene or a gasoline fraction may be used. Preferably a substantial excess of the alcohol is used, and a mixture of alcohols may be used to produce mixed esters. Detailed examples describe the preparation of the di-n-butyl, di-n-amyl, dicapryl, di(2-ethyl-hexyl),dilauryl, di(b -methoxyethyl), and di-(b - 2 - ethylhexoxyethyl), esters of g -ketopimelic acid. Other typical esters mentioned are the di-sec.-butyl, diisobutyl, dihexyl, di-2-methyl pentyl, diheptyl, dioctyl, di-iso-octyl, dinonyl, didecyl, ditrimethylheptyl, diundecyl, diethoxyethyl, dipropoxyethyl, dibutoxyethyl, dipentoxyethyl, di-6-methylpentoxyethyl, dicyclohexyl, and dimethylcyclohexyl esters of g -ketopimelic acid. The esters are useful as plasticizers for natural and synthetic resins, and as functional fluids, for example, as heat transfer media or pressure transfer media. The di(b -methoxyethyl) ester is a good solvent for cellulose acetate and in aqueous solution may be used as a paint and varnish remover.ALSO:Aqueous solutions of di(b - methoxyethyl g -ketopimelate (see Group IV(b)) are useful as paint and varnish removers. Solutions containing 1 part of the ester with up to 2 parts of water are effective for this purpose.