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Abstract: Organotin oxide was used to catalyze the reaction between BPA (bisphenol A) and DMC (dimethyl carbonate), and Ph2SnO (diphenyltin oxide) displays the excellent catalytic performance in transesterification and O-methylation. However, Bu2SnO (dibutyltin oxide), (PhCH2)2SnO (dibenzyltin oxide) and (C6H11)2SnO (dicyclohexyltin oxide) exhibited weaker catalytic activity but higher selectivity for C-methylation product formation. The π–π function between Ph2SnO and BPA provided more chances for their interaction, and π–d interaction between phenyl ring and Sn resulted in catalyst having higher activity in transesterification and O-methylation. O-methylation product formation over Ph2SnO comes from transesterification product decomposition not from direct methylation of BPA with DMC. [Copyright &y& Elsevier]

Abstract: Two-methylcarbonate-ended-BPA (DmC(1)) was selectively synthesized from dimethyl carbonate (DMC) and bisphenol A (BPA) over organotin modified SBA-15. Organotin modified samples were characterized by XRD, FT-IR, BET and TG, and the relations between catalytic performance and catalyst properties were discussed. When heterogeneous SBA-15(CH2)3SnOC4H9 was used as catalyst, DmC(1) achieved better yield and higher selectivity than that obtained over homogeneous (C4H9)2SnO. The confined region effect of SBA-15(CH2)3SnOC4H9 was the main reason to promote the reaction between one-methylcarbonate-ended-BPA (MmC(1)) and DMC. [Copyright &y& Elsevier]

Abstract: Carboxymethylated species were selectively synthesized from dimethyl carbonate (DMC) and bisphenol A (BPA) over TiO2/SBA-15. On the basis of catalyst characterization by means of XRD, FT-IR, HPLC and GC–MS, the relations between catalytic performance and catalyst properties were discussed. Si–O–Ti was active sites for reaction, and the interaction mode between Ti–O–Si and DMC was main factor to determine carboxymethylation and methylation. When DMC was attacked by Ti–O–Si on two oxygen atoms of CH3–O moiety, BPA attacked carbonyl carbon to form carboxymethylated products. If the interaction occurs through the oxygen of C BPA attacked methyl carbon to form methylated products. Chemisorbed H2O over TiO2/SBA-15 made DMC to act as methylating agent. After chemisorbed H2O was removed, carboxymethylated species of two-methylcarbonate-ended-BPA (DmC(1)) and one-methylcarbonate-ended-BPA (MmC(1)) were selectively synthesized. [Copyright &y& Elsevier]

[Display omitted] • TiO 2 with different Lithium doped forms was prepared for the first time. • Ti/Li-6-400 showed the higher activity in transesterification of DMC with BPA. • The activity of surface Ti-O-Li was higher than that of internal Ti-O-Li. • Catalytic activity was related to the alkalinity of catalysts. Lithium doped TiO 2 were prepared by simple impregnation, which was used as heterogeneous catalysts for the transesterification of DMC with BPA. The characterized results of FTIR, XRD, XPS, SEM, TEM and temperature programmed desorption of CO 2 (CO 2 -TPD) showed that the structure and performance of the catalysts were obviously influenced by the doping amount of Li+ and calcining temperature. The optimum catalytic activity was obtained when the molar ratio of Ti/Li reached 6 and the calcination temperature came up to 400 ℃, which was due to Li+ reaction with TiO 2 to form surface Ti-O-Li at 400 ℃ (Ti/Li-6-400). When the transesterification of DMC with BPA was carried out at 160–180 ℃ over Ti/Li-6-400, BPA conversion reached 46.67%, and the yields of one-methylcarbonate-ended-BPA (MmC(1)) and two-methylcarbonate-ended-BPA (DmC(1)) achieved 36.36% and 5.97%, respectively, and only 9.3% methylation selectivity was detected. In addition, the possible transesterification mechanism was provided. [ABSTRACT FROM AUTHOR]