STUDIES ON THE STABILITY OF THE DIMER OF 2,4-TOLYLENE DIISOCYANATE
Pritam Singh, Jean L. Boivin · Canadian Journal of Chemistry · 1962
A series of carbamates of the dimer of 2,4-tolylene diisocyanate was prepared from different alcohols, leaving the uretidine-dione ring unaffected. Di-sec-butylamine and dibenzylamine did not affect the dimer ring and reacted only with the two free isocyanate groups. However, di-n-propylamine, di-n-butylamine, and di-n-amylamine ruptured the ring, and diureas of the monomer were obtained. Alkaline reduction changed the dimer ring into a ureylene link and a N-substituted amide was formed by the Leuckart reaction. Hydrazine hydrate gave an unsymmetrical monosubstituted urea whereas hydroxylamine broke the ring and gave the corresponding oxime of the formamide.