Novel azocarboxylic esters useful as polymerisation initiators and process for their manufacture.

摘要

Azocarboxylic esters useful as polymerisation initiators, especially for polymerisation in aqueous medium, have the general formula <CHEM> in which R is the residue of an aliphatic polyhydroxy compound R(OH)q+1 after removal of one hydroxyl group therefrom, R1 is a methyl or ethyl group or a grouping of the formula -COO(CnH2nO)p-R(OH)q; R2 is a methyl group or a beta carboxyethoxy group and R3 is a methyl group or an ethyl group, or R2 and R3 together with the intermediate carbon atom form a cyclohexyl group: R4 is a methyl group and R5 is a methyl group, an ethyl group, a beta -carboxyethoxy group of a beta -methoxy- beta beta -dimethylethyl group, or R4 and R5 together with the intermediate carbon atom form a cyclohexyl group n has one or more of the values 2, 3 and 4, p is zero or an integer from 1 to 100, preferably from 1 to 50, and q has the value 2 of 4. The esters can be prepared by reacting a corresponding azonitrile or azobisnitrile with a stoichiometrically equivalent amount of an aceral or ketal of the formula <CHEM> wherein R6 is hydrogen or an alkyl or aryl group and R7 is an alkyl or artl group, or R6 and R7 together with the intermediate carbon atom form a cyclohexyl group, in the presence of hydrogen chloride gas under anhydrous conditiond, followed by hydrolysis of the product.