A quantum-chemical insight on chemical fixation carbon dioxide with epoxides co-catalyzed by MIL-101 and tetrabutylammonium bromide

作者：Hu, Tian-ding; Sun, Yu-wang; Ding, Yi-hong^*

来源：Journal of CO2 Utilization, 2018, 28: 200-206.

DOI：10.1016/j.jcou.2018.09.027

• Metal-organic frameworks
• Ionic liquid
• CO2 conversion
• Synergistic catalysis
• DFT calculations

The fixation of CO2 with epoxides catalyzed by metal-organic frameworks (MOFs) has been the ongoing hot topic investigated extensively in experiment throughout the years. Recent experimental studies have revealed that the MIL-101(Cr) can effectively catalyze the cycloaddition conversion of CO2 with the aid of the tetrabutylammonium bromide(TBAB). However, the mechanistic details remain largely unraveled. In this work, we undertook a detailed DFT study on the cycloaddition reaction catalyzed by the binary system MIL-101/TBAB in comparison with the non-catalyzed, MIL-101-catalyzed alone and TBAB-catalyzed alone reactions. The threestep route involving the consecutive ring-opening of PO (propylene oxide), insertion of carbon dioxide, and ringclosure of cyclic carbonate was found to be kinetically more favorable than the two-step route (ring-opening of PO and ring-closure of cyclic carbonate). Based on the rate-determining activation energy barrier, the cycloaddition of CO2 to PO proceeds in a much easier way in the presence of MIL-101/TBAB (18.11 kcal mol(-1)) than the non-catalyzed (57.67 kcal mol(-1)), MIL-101-catalyzed (46.89 kcal mol(-1)) and TBAB-catalyzed (26.86 kcal mol(-1)) alone reactions. The computational findings can satisfactorily explain the available experimental observations, enabling a molecular-level understanding of congener catalysts for organic carbonate production as well as the rational design of more powerful MOF-orientated catalysts.

• 出版日期2018-12
• 单位吉林大学