Catalysis Letters, Vol.139, No.1-2, 38-41, 2010
Transition-Metal-Substituted Keggin-Type Germanotungstates for Catalytic Conversion of Carbon Dioxide to Cyclic Carbonate
The tetra-n-heptylammonium salts of transition-metal-substituted (TMS) Keggin type germanotungstates [(n-C7H15)(4)N](n)GeW11MO39 (M = Mn2+, Fe3+, Co2+, Ni2+, Cu2+ and Zn2+, n = 5 or 6) were found to be efficient catalysts for cyclic carbonates synthesis from epoxides and CO2 under solvent-free and halogen-free condition. The catalytic activities were significantly influenced by the transition metal and the countercation and a plausible mechanism was proposed.