A Mechanistic Study for Cyclic Carbonate Formation from CO2 and Epoxides Catalyzed by Ruthenium 2,2 '-Bipyridine Complex

作者：Bu Zhanwei^*; Wang Zhiqiang; Qin Gang; Cui Yuanchen; Cao Shaokui

来源：Acta Chimica Sinica, 2010, 68(18): 1871-1875.

• ruthenium 2,2 '-bipyridine complex
• catalysis
• carbon dioxide
• epoxides
• mechanism

The cycloaddition of CO2 with various epoxides to afford cyclic carbonates was investigated via the catalysis of ruthenium 2,2'-bipyridine complex RuCl3(2,2'-bipy)(CH3OH) and hexadecyl trimethyl ammonium chloride (CTAC). The cyclic carbonate formation mechanism was studied by using electrospray ionization mass spectrometry (ESI-MS) in the case of cycloaddition of CO2 with propylene oxide (PO). Two intermediate complexes, RuCl3(2,2'-bipy)(PO) and RuCl3(2,2'-bipy)(PC), in the proposed reaction mechanism were successfully detected via ESI-MS measurement. Experimental results suggested that the initial coordination of epoxide is likely to occur first through the methanol ligand replacement in RuCl3(2,2'-bipy)(CH3OH). A nucleophilic attack of the chloride anion in CTAC on the less sterically hindered beta-carbon atom of the coordinated epoxide is responsible for the epoxide ring-opening, CO2 succeedingly inserts into the Ru-O bond and ring-closure happens subsequently yielding the cyclic carbonate.

• 出版日期2010-9-28
• 单位河南大学; 郑州大学