Institute of Coal Chemistry;
Chinese Academy of Sciences;
Taiyuan;
030001;
China;
Center of Materials Science and Optoelectronics Engineering;
University of Chinese Academy of Sciences;
Beijing;
100049;
China;
Department of Chemistry;
University of Copenhagen;
DK-2100 Copenhagen;
Denmark;
Sinopec Shanghai Petrochemical Co.;
Ltd.;
Shanghai;
200540;
China;
Green solvents; Acidity; Basicity; ^(31)P-TMPO NMR; ^(1)H-pyrrole NMR;