Development of bifunctional metal catalysts for cyclic carbonate synthesis from oxirane and carbon dioxide

Abstract

In Chapter I, a urea-functionalized salen aluminum complex has been developed. The catalyst has a bimetallic scaffold due to the presence of the urea moiety. The reaction was carried out in a stainless bomb reactor under mild conditions (10 bar CO2 and 90 ˚C, neat). The turnover frequency (TOF) of the bis-urea salen catalyst was three times higher than that of the μ-oxo-bridged catalyst and thirteen times higher than that of the monomeric salen aluminum catalyst. The bimetallic pathway was determined by urea additive studies and kinetic studies. The bimetallic structures of the bis-urea aluminum salen catalyst were supported by the reported bis-urea salen Ni catalyst structures. In Chapter II, an imidazolium[1,5-a]pyridinyl carbene – phosphine ligand precursor has been developed. We established a screening system for the synthesis of acrylate and solved the over-reduction problem that occurred during the catalyst synthesis process. We were able to confirm the reaction conditions of the catalyst we synthesized by resolving the reproducibility issues of the known reaction conditions