Efficient production of methanol and diols via the hydrogenation of cyclic carbonates using copper-silica nanocomposite catalysts

Copper-silica nanocomposite catalysts with a uniform Cu dispersion prepared by a precipitation-gel method have been found to be highly efficient in the heterogeneous catalytic hydrogenation of CO2-derived cyclic carbonates, providing an indirect but practical approach for the transformation of CO2 to methanol with the co-production of diols under relatively mild conditions. The catalysts possessed remarkable stability in both batch and fixed-bed continuous flow reactors especially after promotion with B2O3. The reaction was found to depend sensitively on the Cu particle size, the surface acidity-basicity and the Cu valence of the catalysts. The synergetic effect between balanced Cu-0 and Cu+ sites was considered to play a critical role in attaining high yields of methanol and diols.