Phosgene-free synthesis of carbamates over zeolite-based catalysts

Abstract

Alkyl and aryl carbamates are synthesized in high yields (≥80%) at mild reaction conditions by reaction of the corresponding amine, CO₂ and alkyl halides over either titanosilicate molecular sieves or metal phthalocyanine complexes encapsulated in zeolite-Y. The catalysts could be reused with little or no loss in activity. In contrast to hitherto known catalysts for carbamate synthesis, the zeolite-based catalysts of the present study do not require additional onium salts as co-catalysts.