The thermal dehydrochlorination of N, X'-dialkylallophanoyl chlorides afforded isocyanates in high yield. While X, S'-dialkylallophanoyl chlorides are virtually unaffected by base, the cyclic allophanoyl chlorides (2-imidazolidinone-N-carbonyl chlorides) could be dehydrochlorinated to the corresponding diisocyanatee at room temperature using a tertiary amine. The influence of various catalysts on the thermal decomposition of allophanoyl ...