1. School of Chemistry and Chemical Engineering; Beijing Institute of Technology; 5 South Zhongguancun street Beijing 100081 (P.R. China
2. Institute of Chemical Materials; China Academy of Engineering Physics, Mianyang; 621050 (P.R. China
3. Division of Ionic Liquids and Green Engineering; Institute of Process Engineering; Chinese Academy of Sciences, Beijing; 100190 (P.R. China