Highly Efficient and Selective Synthesis of Methyl Carbonate-Ended Polycarbonate Precursors from Dimethyl Carbonate and Bisphenol A

In this work, metal acetylacetonates were used to catalyze the reaction of dimethyl carbonate (DMC) and bisphenol A (BPA) and high conversion of BPA and excellent selectivity of carboxymethylation products were achieved. Among these, zirconium­(IV) acetylacetonate (Zr­(acac)4) exhibited the best catalytic performance with BPA conversion of 85.2% and carboxymethylation products selectivity up to 99.0%, which has been the most efficient catalyst so far to the best of our knowledge. According to Fourier transform infrared (FT-IR) characterization and density functional theory (DFT) calculations, we found that the most active cis–cis interaction species 3 formed between a Zr cation and two oxygen atoms from the CH3–O moiety of DMC greatly promoted the selective occurrence of the carboxymethylation reaction. It was demonstrated that the catalytic performance of metal acetylacetonate was related to d-electrons and interaction mode of the metal, and the plausible reaction mechanism was proposed.