One-Pot Synthesis of Disubstituted Urea from Carbon Dioxide, Propylene Oxide, and Amines Catalyzed by Imidazolium-Tetraiodoindate

Article abstract of DOI:10.1002/bkcs.11363

In this article, synthesis of 1,3-disubstituted urea (DSU) from three component reagent systems comprising amine, carbon dioxide, and propylene oxide is described. DSU is synthesized in the presence of a variety of ionic liquids (ILs) with/without promoters. Among used ILs, 1-butyl-3-methylimidazolium tetraiodoindate^III (represented as [Bmim][InI₄]) is found to give the highest DSU product. A serious experiment clearly indicates that the tetraiodoindate anion plays an important role for the selective production of the DSU. Based on the in situ infrared spectroscopic studies, a plausible reaction mechanism for producing dicyclohexylurea from cyclohexylamine is proposed. The synthesis and characterization of [Bmim][InI₄] are given in details. Moreover, the effect of reaction variables such as time, temperature, pressure, and the molar ratio of substrate to catalyst is also studied.