Process for the preparation of an azonitrile dicarboxylic acid initiator

Abstract

Disclosed are processes for the preparation of an azonitrile initiator having both a low salt and low water content of the formula ##STR1## This initiator is prepared by reacting a keto acid of the formula ##STR2## with M(CN).sub.x, a hydrazine source, and hydrochloric acid to form ##STR3## The hydrazo intermediate is reacted with chlorine gas in the presence of acetone to oxidize the hydrazo intermediate to the azonitrile initiator. After oxidation, the reaction mixture is permitted to separate into layers. The bottom aqueous layer is removed and discarded. The upper acetone-azonitrile initiator level is treated with solid calcium chloride or a saturated calcium chloride or sodium chloride solution. This salting out procedure generates an additional water layer that further contains (M(Cl).sub.x. The final acetone-azonitrile initiator solution has a low salt and low water content. R.sub.1 is an alkyl group containing from about 1 to about 12 carbon atoms, R.sub.2 is non-existent or an alkylene group containing from 1 to about 12 carbon atoms, or a cycloalkylene or alkyl cycloalkylene group containing from about 3 to about 12 carbon atoms, and M is a metal comprising lithium, sodium, potassium, magnesium, or calcium.