Novel catalytic systems containing n-BuSn(O)OH for the transesterification of dimethyl carbonate and phenol

Novel catalytic systems containing n-butylstannonic acid (n-BuSn(O)OH) were used to synthesize methyl phenyl carbonate (MPC) and diphenyl carbonate (DPC) by the transesterification of dimethyl carbonate (DMC) with phenol in atmospheric conditions. The catalytic system consisting of n-BuSn(O)OH and cuprous iodide (CuI) had the highest activity for the transesterification. When the reaction was carried out between 150 and 180 °C, with a molar ratio of n-BuSn(O)OH to CuI of 1:1, a catalyst amount 0.005 (molar ratio to DMC), a reaction time 10 h, a molar ratio of DMC to phenol of 2:1, a dropping time of DMC 6 h, the conversion of phenol was 67.2%, and the selectivity of MPC and DPC was 40.2 and 59.6%, respectively. Upon comparison of the activities of Cu2O, CuX (X = Cl, Br, I) and the catalytic system being composed of n-BuSn(O)OH and Cu2O/CuX, it was found that Cu2O and CuX were excellent promoters, and the stronger was the anion electronegativity in the promoter, the weaker was the promoting catalysis of the promoter.

n-BuSn(O)OH and Cu2O/CuX (X = Cl, Br, I) constituted a highly efficient catalytic system for the transesterification of DMC and phenol. Cu2O and CuX were demonstrated to be excellent promoters, and the stronger was the anion electronegativity in the promoter, the weaker was its promoting catalysis. Figure optionsDownload as PowerPoint slide