Effective synthesis of cyclic carbonates from CO<sub>2</sub> and epoxides catalyzed by KI/cucurbit[6]uril

Shi, Jinghua; Song, Jinliang; Ma, Jun; Zhang, Zhaofu; Fan, Honglei; Han, Buxing

doi:10.1351/PAC-CON-12-10-09

Pure Appl. Chem., 2013, Vol. 85, No. 8, pp. 1633-1641

http://dx.doi.org/10.1351/PAC-CON-12-10-09

Published online 2013-04-04

Effective synthesis of cyclic carbonates from CO₂ and epoxides catalyzed by KI/cucurbit[6]uril

Jinghua Shi, Jinliang Song, Jun Ma, Zhaofu Zhang, Honglei Fan and Buxing Han*

Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China

Abstract: The development of efficient, inexpensive, and nontoxic catalysts for cycloaddition of CO₂ with epoxides to produce five-membered cyclic carbonates is a very interesting topic. In this work, cycloaddition of CO₂ with propylene oxide (PO) to produce propylene carbonate (PC) catalyzed by potassium halides (KCl, KBr, and KI) in the presence of cucurbit[6]uril (CB[6]) was studied at various conditions. It was discovered that the potassium halides and CB[6] had excellent synergetic effect in promoting the reaction, and the KI/CB[6] catalytic system was the most efficient among them. The decrease of the activity and selectivity of KI/CB[6] was negligible after the catalytic system was reused five times. Further study indicated that the KI/CB[6] catalytic system was also very active and selective for the cycloaddition of CO₂ with other epoxides, such as glycidyl phenyl ether, epichlorohydrin, and styrene oxide. The mechanism for the synergetic effect of KI and CB[6] was also discussed.