Recent advances in the coupling of CO2 and epoxides into cyclic carbonates under halogen-free condition
Feng Zhang, Yanyan Wang, Xiaochun Zhang, Xiaochun Zhang, Xiangping Zhang, Xiangping Zhang, Huizhen Liu, Buxing Han
Abstract
The chemical transformation of CO 2 and epoxides into cyclic carbonates has been receiving much attention and is one of the successful examples for CO 2 utilization as carbon resource. Many catalysts containing halide anions have been explored and exhibit excellent catalytic activity. However, halogen salt is generally toxic and corrosive to reactors. From a green chemistry perspective, it is more attractive to develop a halogen-free catalyst with excellent performance. Herein, a review of recent research progress of halogen-free catalysts in the cycloaddition of CO 2 and epoxide is presented. According to previous experimental and theoretical works, two possible strategies for achieving the halogen-free process were summarized. The relationship between catalytic activity and catalyst structure, the mechanism of CO 2 activation should be both studied deeply combined with experimental results and DFT calculation, which can guide the design of new catalysts and realize halogen-free process under mild reaction conditions. • Halogen-free catalysts for coupling reaction of CO 2 /epoxide were summarized. • Bi- or multi-functional catalysts were more effective for CO 2 cycloaddition. • Halogen-free process could be achieved by the synergistic effect of functional groups. • Lewis acid-base or Lewis acid-nucleophile facilitate the ring-opening of epoxide. • Two potential catalysts: metal-based porous catalysts and supported heterogeneous ILs.