16530-58-8Relevant articles and documents
Lithium doped TiO2 as catalysts for the transesterification of bisphenol-A with dimethyl carbonate
Liang, Yanan,Su, Kunmei,Cao, Lei,Li, Zhenhuan
, p. 16 - 23 (2019/01/04)
Lithium doped TiO2 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 CO2 (CO2-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 TiO2 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.
Study on the transesterification and mechanism of bisphenol A and dimethyl carbonate catalyzed by organotin oxide
Liang, Yanan,Su, Kunmei,Cao, Lei,Gao, Yuan,Li, Zhenhuan
, p. 2171 - 2182 (2019/06/21)
(CF3C6H4)2SnO, (CH3C6H4)2SnO and Ph2SnO were successfully synthesized for the transesterification of DMC with BPA. The products of mono-methylcarbonate-ended-BPA (MmC(1)) and two-methylcarbonate-ended-BPA (DmC(1)) were selectively synthesizedthem. The catalysts were characterized by FT-IR, TG and XPS. When Ph2SnO was used as the catalyst at 170?°C, the BPA conversion reached to 28.60% and the transesterification selectivity reached to 98.35%. As for (CF3C6H4)2SnO, BPA conversion and transesterification selectivity declined to 12.48% and 64.74%, respectively. The BPA conversion increased to 42.83%, but the transesterification selectivity declined to 44.55%(CF3C6H4)2SnO. Notability, the higher transesterification selectivity of Ph2SnO was due to its lowest electron binding energy of Sn4+. More importantly, the DMC adsorption, activation and decomposition process(CF3C6H4)2SnO, (CH3C6H4)2SnO and Ph2SnO were characterized by TG–MS and in situ DRIFT techniques, which provided more information about the mechanism of transesterification and methylation.
METHODS OF MANUFACTURE OF SALTS OF HYDROXY-SUBSTITUTED AROMATIC COMPOUNDS AND POLYETHERIMIDES
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Paragraph 0042; 0043, (2015/11/09)
A method for the manufacture of a metal salt of a hydroxy-substituted aromatic compound comprises: contacting a hydroxy-substituted aromatic compound with a base comprising a metal cation in molten diphenyl sulfone or sulfolane to provide a mixture compri
Study on the reaction between bisphenol A and dimethyl carbonate over organotin oxide
He, Xiaolong,Li, Zhenhuan,Su, Kunmei,Cheng, Bowen,Ming, Jun
, p. 20 - 23 (2013/05/09)
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), (PhCH 2)2SnO (dibenzyltin oxide) and (C6H 11)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.
Hydrosilanes are not always reducing agents for carbonyl compounds, II: Ruthenium-catalyzed deprotection of tert-butyl groups in carbamates, carbonates, esters, and ethers
Hanada, Shiori,Yuasa, Akihiro,Kuroiwa, Hirotaka,Motoyama, Yukihiro,Nagashima, Hideo
supporting information; experimental part, p. 1021 - 1025 (2010/04/27)
Hydrosilanes act as a reagent to cleave the C-O bond of OtBu groups in carbamates, carbonates, esters, and ethers by catalysis of a triruthenium cluster. The reaction offers a novel deprotection method, for OiBu groups under neutral conditions, showing unique selectivities that have never been accomplished with conventional Bronsted or Lewis acidic promoters. Possible mechanisms for C-O cleavage are discussed on the basis of NMR spectroscopic analysis.
