Mechanism of Cyclic Carbonate Synthesis from Epoxides and CO₂

Abstract

Three interconnected catalytic cycles account for the title reaction catalyzed by a bimetallic aluminum(salen) complex and Bu4NBr. In the first, Bu4NBr acts as a nucleophile to activate the epoxide. In the second, Bu3N generated in situ serves to activate CO2. In the third, the aluminum(salen) complex brings the two activated species together so that the key bonds can be formed intramolecularly.

Preparation of lignin/glycerol-based bis(cyclic carbonate) for the synthesis of polyurethanes

“…The cycloaddition of CO 2 with mono-epoxy compound have been widely studied and numerous catalysts have been developed to obtain high yield and selectivity, such as halide salts, 35 quaternary ammonium salts 36,37 ionic liquids (ILs) 38,39 and metal catalysts. 40,41 With the significant progress in NIPUs preparation via the polyaddition between BCC and multifunctional primary alkyl amines, the screen of highly effective catalysts for the conversion of bisepoxy compounds into BCC is of great important, as the structures and properties of as prepared NIPUs are greatly influenced by the ratio of carbonate to amine groups.…”

Phosphorus‐based Bifunctional Organocatalysts for the Addition of Carbon Dioxide and Epoxides

“…[7] There are numerous reports on catalysts for the coupling of CO 2 with epoxides. Especially organocatalysts based on pyridinium, [8] imidazolium, [9] ammonium, [10] and phosphonium salts [11] as well as carbenes [12] have been studied extensively as both single catalysts and co-catalysts. However, under metalfree conditions these catalysts usually require harsh reaction conditions: temperatures > 100 8C and/or pressures > 2.0 MPa.…”

Environmentally benign chemical fixation of CO2 catalyzed by the functionalized ion-exchange resins

“…This fact presumably implies that the basic species may be assumed to activate CO 2 , and thus the basicity may play a crucial role in the present catalytic system. The functional group of D301R is a tertiary amino group, which is assumed to activate CO 2 through formation of the zwitterionic species [42][43][44][45]. However, the primary amine group in D380 likely tends to form the stable carbamate salts, thus resulting in lower activity (entry 10 vs. 11).…”

“…Activation of CO 2 itself by a nucleophilic species should not be neglected. There have been numerous reports about interactions between CO 2 and tertiary amines [42][43][44][45]. The catalytic utilization in chemical fixation of CO 2 was intensively investigated as well [46][47][48][49][50][51][52].…”