(546a) Effect of Confined Ion Cluster Scale on Catalytic CO2 Conversion into Cyclic Carbonates

Suojiang Zhang, Qian Su and Weiguo Cheng

Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, P.O. Box 353, Beijing, 100190, China

*Corresponding author:sjzhang@ipe.ac.cn

In recent years, the atom-economy reaction of CO₂ with epoxides into cyclic carbonateshas attracted extensive attention in both academia and industry. Up to now, different forms of ionic liquids (ILs)have been developed for catalytic conversion of CO₂ into cyclic carbonates, such as bulk ILs, supported ILs and poly(ionic liquids).^1-4Though a great improvement has been achieved in catalytic performance of these ILs system, which mostly consists of clusters with different ion numbers. What scale of ion cluster functions most efficiently on this transformation is still unknown and lacking of effective way to explore.

Confinement method provides possibility for this exploration.⁵ By screening micro- and meso-porous materials with certain size of open channels as limited space, ion clusters of certain scale, ranging from one to dozens of angstroms, could be confined and isolated via in-situ synthesis in each space. In this work, molecular sieves were adopted as limited spaces for investigation about the effect of ion cluster scale on CO₂ conversion into cyclic carbonates. Through experiment test and molecule simulation, the space size of molecular sieves was rigorously screened to fix ion clusters firmly in and allow reactant and target product molecules free in-and-out. By using different size of spaces, different scale of clusters with varying ion numbers could be confined and the corresponding catalytic activity along with scale change, especially from one to dozens of angstroms, would be evaluated. This study not only optimizes the ion cluster scale which is needed for efficient synthesis of cyclic carbonates, but also provides an efficient way to investigate angstrom scale reaction mechanism, which is of great significance in both academic and industrial areas.

Keywords: ionic liquids, CO₂, cyclic carbonates, ion cluster, scale

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