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.