Conversion of Residual Ethylene Oxide in the Ionic Liquid Catalyzed CO2 Cycloaddition Process

Conversion of residual ethylene oxide in the ionic liquid catalyzed CO₂ cycloaddition process

Jian Sun, Weiguo Cheng, Jinquan Wang, Junping Zhang and Suojiang Zhang

Institute of Process Engineering, Chinese Academy of Sciences,100190, Beijing, PR China

*Contact information: jsun@home.ipe.ac.cn

Recently, the synthesis of cyclic carbonates via cycloaddition of CO₂ to epoxides is much attractive not only because of its efficiency in CO₂ conversion, but also becuase of its widely derivative high-value chemicals.^[1] Although a number of efficient catalysts including ionic liquids (ILs) have been developed, ^[2] attention on the trace residual epoxide in the reaction system, especially in gas phase, is rarely covered, which could cause a potential explosion of epoxide when unreacted CO₂ is compressed for recyle. As a continous work for CO₂ conversion,^[3] herein, studies on the conversion of residual trace epoxide (0.2 wt%) in an IL catalyzed CO₂ cycloaddition process to produce ethylene carbonate (EC) were carried out. The effect parameters including pressure, temperature, time and solvents (e.g. H₂O, EC+ethylene glycol+H₂O, BmimCl, BmimPF₆, BmimBF₄, etc) were systematically screened, and a >99.9% conversion of EO could be realized by reduding the partial pressure of EO in the system. The results indicated that a vapor-liquid equilibriuma of EO in the reaction system has a more important effect on EO elimination rather than reaction time and temperature.

Refferences

[1]  B. Schaffner, F. Schaffner, S.P. Verevkin and A. Borner, Chem. Rev., 2010, 110, 4554.

[2]  a) J. M. Zhang, J. Sun, X. C. Zhang, Y. S. Zhao, S. J. Zhang. Greenhouse Gas Sci Technol., 2011, 2:142-159; b) M. North, R. Pasquale, C. Young, Green Chem., 2010, 12, 1514.

[3]  a) J.Q. Wang, J. Sun, W.G Cheng, S.J. Zhang. Phys. Chem. Chem. Phys., 2012, 14, 11021; b) J. Sun, L. J. Han, W. G. Cheng , J. Q. Wang, X. P. Zhang, S. J. Zhang. ChemSusChem, 2011, 4: 502; c) J. Sun, J.Q. Wang, W. G. Cheng, J. X. Zhang, X. H. Li, S. J. Zhang, Y. B. She. Green Chem., 2012, 14: 654; d) J. Sun, W. G. Cheng, W. Fan, Y. H. Wang, Z. Y. Meng, S. J. Zhang. Catal. Today, 2009, 148: 361.

Acknowledgments

This work was supported by National Basic Research Program of China (2009CB219901), and National Science Fund of China (21006117).