GB639929A - Improvements in or relating to polycarboxylic acids and method of preparing the same - Google Patents

Abstract

In the reaction disclosed in the parent Specification between a saturated aliphatic b -lactone and an inorganic salt in a polar solvent reaction medium to give salts of b -substituted carboxylic acids, if excess lactone is present and the salt is a cyanide b -polyacyloxy carboxylic acid salts are obtained having a cyano group b -substituted in an acyloxy group. For details of cyanides and lactones used (see Group IV (b)). The Specification as open to inspection under Sect. 91 is not restricted to the use of saturated aliphatic lactones but also specifies aromatic and unsaturated aliphatic lactones which may be substituted with groups containing halogens, nitrogen, oxygen or sulphur. This subject-matter does not appear in the Specification as accepted.ALSO:The b -cyano-substituted carboxylic acids disclosed in the parent Specification by the reaction of a lactone of the general formula <FORM:0639929/IV (b)/1> where R1, R2, R3 or R4 are hydrogen or alkyl groups, with a cyanide ionizable in the polar solvent reaction medium are hydrolysed to give the corresponding b -carboxy-substituted carboxylic acid or salt. It is preferred that 1-5 mols. of cyanide per mol. of b -lactone be used, that the temperature be below room temperature for the first stage and that water is the solvent. Hydrolysis by any known method may be employed, but if alcohol-water solution is used as the hydrolysis medium esters of the alcohol with the polycarboxylic acid may be produced. The reaction mixture obtained by treating b -propiolactone with sodium cyanide is hydrolysed with (a) aqueous hydrochloric acid solution and (b) aqueous sodium hydroxide solution to give succinic acid (after acidification in (b)) and with (c) alcoholic sulphuric acid solution to give diethyl succinate. The Specification as open to inspection under Sect. 91 is not restricted to the use of saturated aliphatic b -lactones, but also specifies lactones of b -hydroxy-monocarboxylic acids containing cycloalkyl, aryl and aralkyl substituents, lactones of unsaturated b -hydroxy carboxylic acids, mono- and di-b -lactones of di-carboxylic acids and b -lactones containing oxygen, nitrogen, sulphur and halogens combined in such groupings as nitro, ether, amino and hydroxy as well as the carbonoxy structure and hydrogen atoms. This subject-matter does not appear in the Specification as accepted.