Isocyanate derivatives and their production

摘要

This invention describes a method of forming bisulphite adducts of aliphatic isocyanates bearing an aromatic moiety by mixing an aqueous solution of a bisulphite adduct forming agent with a solution of an isocyanate bearing an aromatic moiety in a substituted pyrrolidinone containing a catalytic amount of a substance which catalyses the bisulphite adduct forming reaction, the isocyanate being kept well dispersed so that the adduct is formed as a solution in the aqueous phase.