Direct synthesis of dimethyl carbonate from methanol and carbon dioxide using heteropolyoxometalates: the effects of cation and addenda atoms

The direct synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide over a series of Keggin-type heteropolyoxometalates has been investigated. The effects of the cations and the addenda atoms of the heteropolyoxometalate on the conversion and the product selectivities were investigated. The results showed that Co1.5PW12O40 was the best catalyst of the series. The effect of reaction temperature and CO2 pressure on the direct synthesis of DMC demonstrated that lower temperatures and higher pressures are favorable for the synthesis of DMC. Higher temperatures favor the formation of dimethoxymethane (DMM) and methyl formate (MF).