- Lithium doped TiO2 as catalysts for the transesterification of bisphenol-A with dimethyl carbonate
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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.
- Liang, Yanan,Su, Kunmei,Cao, Lei,Li, Zhenhuan
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- Motional Heterogeneity and Polymorphism of Bisphenol-A Diacetate
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Two polymorphs of bisphenol-A diacetate were characterized by solid-state (13)C cross-polarization magic-angle spinning NMR, X-ray powder diffraction and differential scanning calorimetric measurements.The structure of one polymorph was determined by single-crystal x-ray diffraction methods, and shown to have two molecules in the asymmetric unit.The two polymorphs show markedly different molecular mobilities, as reflected in variable-temperature solid-state NMR measurements, with one-polymorph exhibiting motional heterogeneity in the flipping of the phenylene rings.KEY WORDS: (13)C NMR; (13)C CP MAS; Motional heterogeneity; Polymorphism; Bisphenol-A diacetate
- Casarini, Daniele,Harris, Robin K.,Kenwright, Alan M.
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- Promotion of organotin modified SBA-15 in the selective carboxylation of BPA with DMC
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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)3SnOC4H 9 was used as catalyst, DmC(1) achieved better yield and higher selectivity than that obtained over homogeneous (C4H 9)2SnO. The confined region effect of SBA-15(CH 2)3SnOC4H9 was the main reason to promote the reaction between one-methylcarbonate-ended-BPA (MmC(1)) and DMC.
- Li, Zhenhuan,Su, Kunmei,Cheng, Bowen,Ming, Jun,Zhang, Lei,Xu, Yongchao
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- Acetylation of alcohols and phenols by zinc zirconium phosphate as an efficient heterogeneous catalyst under solvent-free conditions
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An efficient method for the acetylation of a wide range of alcohols as well as phenols with acetic anhydride in good to excellent yields under solvent-free conditions, using zinc zirconium phosphate as the catalyst was investigated. The catalyst was characterized by XRD, inductivity coupled plasma-optical emission spectroscopy, and scanning electron microscope. Products are easily isolated and the protocol is mild and green, compared to the existing methods. Graphical abstract: [Figure not available: see fulltext.]
- Hajipour, Abdol Reza,Karimi, Hirbod,Karimzadeh, Morteza
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- Study on the transesterification and mechanism of bisphenol A and dimethyl carbonate catalyzed by organotin oxide
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(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.
- Liang, Yanan,Su, Kunmei,Cao, Lei,Gao, Yuan,Li, Zhenhuan
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- METHOD FOR MANUFACTURING TRIMELLITIC ANHYDRIDE ARYL ESTER
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Disclosed is a method for manufacturing a trimellitic anhydride aryl ester in an efficient, high-yielding manner, wherein carboxylic acid lithium salt is used as a catalyst when a carboxylic acid aryl ester and trimellitic anhydride are caused to undergo an ester exchange reaction to manufacture a trimellitic anhydride aryl ester.
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Page/Page column 8
(2011/11/12)
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- Broensted acidic ionic liquid as an efficient catalyst for acetylation of alcohols and phenols
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A novel Broensted acidic room temperature ionic liquid (1-H-3-methyl-imidazolium bisulfate) is found to catalyze efficiently the acetylation of a wide rang of alcohols as well as phenols with acetic anhydride in good to excellent yields at 50°C under solvent-free conditions. Products are easily isolated by extraction with ether and the protocol is mild and green, compared to the existing method based on toxic solvents.
- Hajipour, Abdol R.,Khazdooz, Leila,Ruoho, Arnold E.
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experimental part
p. 398 - 403
(2009/12/06)
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- Tetrakisphenol
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Formylation of bisphenol-A (1a), with subsequent methylation, oxidation and esterification, gave 2,2-bis-(4-methoxy-3-methoxycarbonylphenyl)-propane (11b). It was transformed into 2,2-bis-[4-methoxy-3-(2-hydroxy-2-propyl)-phenyl]-propane (12b) by the addition of methylmagnesium iodide. This carbinol was condensed with phenol in the presence of dry hydrogen chloride and the title compound was isolated as its tetramethyl ether (4b). Its structure of 2,2-bis-[4-hydroxy-3-(4-hydroxycumyl)-phenyl]-propane (4a) was confirmed by 13C-NMR spectra. In PhOH/HCl medium tetrakisphenol (4a) decomposed and isomerized to bisphenol-A (1a).
- Nowakowska,Daszkiewicz,Kyziol
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p. 1191 - 1197
(2007/10/03)
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