Comparison of the behaviour of supported homogeneous catalysts in the synthesis of dimethylcarbonate from methanol and carbon dioxide: Polystyrene-grafted tin-metallorganic species versus silesquioxanes linked Nb-methoxo species

Two kinds of supported homogeneous catalysts have been used in the synthesis of dimethylcarbonate from methanol and carbon dioxide. Bu2nSn(OMe)2 and [Nb(OMe)5]2, that are reported to be active catalysts under homogeneous conditions, have been bound to a solid support. The moiety [–BunSn(OMe)2] has been grafted on a polystyrene resin by using a phenylethylene spacer, while the [Nb(OMe)5]2 moiety and NbOCl3 have been linked to a silesquioxane matrix. The grafted tin metallorganic species is still active in the synthesis of DMC from methanol and CO2: tin is not lost during catalysis and the heterogenized catalyst can be easily recovered and reused. Conversely, the Nb-silesquioxane adduct is either a monomer or a dimer that does not bring any –OMe moiety linked to Nb and does not react with CO2 nor with methanol, resulting to be inactive in catalysis.

Graphical abstractTwo kinds of supported homogeneous catalysts have been used in the synthesis of dimethylcarbonate from methanol and carbon dioxide. Bu2nSn(OMe)2 and [Nb(OMe)5]2, that are reported to be active catalysts under homogeneous conditions, have been bound to a solid support. The moiety [–BunSn(OMe)2] has been grafted on a polystyrene resin by using a phenylethylene spacer, while the [Nb(OMe)5]2 moiety and NbOCl3 have been linked to a silesquioxane matrix. The grafted tin metallorganic species is still active in the synthesis of DMC from methanol and CO2: tin is not lost during catalysis and the heterogenized catalyst can be easily recovered and reused. Conversely, the Nb-silesquioxane adduct is either a monomer or a dimer that does not bring any –OMe moiety linked to Nb and does not react with CO2 nor with methanol, resulting to be inactive in catalysis.Figure optionsDownload full-size imageDownload as PowerPoint slide