The addition of platinum over the B2O3/TiO2-ZrO2 remarkably enhanced its catalytic stability in the vapor phase Beckmann rearrangement of cyclohexanone oxime under the carder gas of H2. The content of coke deposited ...The addition of platinum over the B2O3/TiO2-ZrO2 remarkably enhanced its catalytic stability in the vapor phase Beckmann rearrangement of cyclohexanone oxime under the carder gas of H2. The content of coke deposited on catalyst surface was decreased from 1.92% over the B2O3/TiO2-ZrO2 to 1.14% over the platinum promoted B2O3/TiO2-ZrO2 after reaction of six hours. This result indicates that the platinum added on the B2O3/TiO2-ZrO2 catalyst plays an important role in reducing the coke formation on the catalyst surface.展开更多
Four different ZSM 5 zeolites are tested for the gas phase Beckmann rearrangement of cyclohexanone oxime (CHO) into lactam. B ZSM 5 derived titanosilicalite (Ti ZSM 5) exhibits catalytic performances comparabl...Four different ZSM 5 zeolites are tested for the gas phase Beckmann rearrangement of cyclohexanone oxime (CHO) into lactam. B ZSM 5 derived titanosilicalite (Ti ZSM 5) exhibits catalytic performances comparable to hydrothermally synthesized titanosilicalite (TS 1), much better than B ZSM 5 and Al ZSM 5. The effect of reaction conditions (solvent, feed space velocity, and water) on the catalytic performance of Ti ZSM 5 is studied. It is found that a quantitative relationship exists among the feed space velocity, the reaction time, and the CHO constant conversion. Ethanol or methanol as solvent shows higher activity, lactam selectivity, and stability than benzene and n hexanol. The addition of water to the rearrangement with a maximum amount of 1.0 mole per mole CHO results in the increase of CHO conversion while no meaningful changes in lactam selectivity and stability are observed.展开更多
Silicalite-1 was hydrothermally synthesized in the presence of different concentrations of Na+using tetrapropylammonium hydroxide(TPAOH)as a template.The synthesis was followed by a base treatment.The silicalite-1samp...Silicalite-1 was hydrothermally synthesized in the presence of different concentrations of Na+using tetrapropylammonium hydroxide(TPAOH)as a template.The synthesis was followed by a base treatment.The silicalite-1samples were characterized using X-ray diffrac-tion,scanning electron microscopy,N2 adsorption,X-ray photoelectron spectroscopy,Fourier transform infrared spectroscopy and NH3 temperature-programmed deso-rption.The samples were used as catalysts for the vapor phase Beckmann rearrangement of cyclohexanone oxime.During the synthesis,the sodium ions were incorporated onto the silicalite-1 crystals,but were then removed by the base treatment.All the catalysts exhibited nearly complete conversion of cyclohexanone oxime toε-caprolactam with selectivities grater than 95%.Addition of less than 2.5 mol-%Na^(+)(relative to TPAOH)did not influence the catalytic properties.However,for Na+concentrations≥5 mol-%,the particle sizes of silicalite-1 increased and the catalytic activities decreased,which can be attributed to carbon deposition.The results in this work are of great importance for the polymer industry.展开更多
A selective reaction of cyclohexanone oxime-blocked tolylene-2,4-diisocyanate（2,4-TDI）with amino siloxane was observed,in which amines were capable of discriminating two reactive groups in the 2,4-TDI molecule.Thus,...A selective reaction of cyclohexanone oxime-blocked tolylene-2,4-diisocyanate（2,4-TDI）with amino siloxane was observed,in which amines were capable of discriminating two reactive groups in the 2,4-TDI molecule.Thus,tolylene-2-tert-butyldimethylsilyloxyethyl carbamide-4-cyclohexanone oxime carbamate was synthesized and its precise structure was determined by single-crystal X-ray diffraction.Moreover,it was found that oxime-blocked isocyanate could react selectively with the–NH2group with the–OH group unprotected in ethanolamine.展开更多
文摘The addition of platinum over the B2O3/TiO2-ZrO2 remarkably enhanced its catalytic stability in the vapor phase Beckmann rearrangement of cyclohexanone oxime under the carder gas of H2. The content of coke deposited on catalyst surface was decreased from 1.92% over the B2O3/TiO2-ZrO2 to 1.14% over the platinum promoted B2O3/TiO2-ZrO2 after reaction of six hours. This result indicates that the platinum added on the B2O3/TiO2-ZrO2 catalyst plays an important role in reducing the coke formation on the catalyst surface.
基金the Foundations for Basic Research ofTsinghua U niversity and of China Petrochem icalCompany
文摘Four different ZSM 5 zeolites are tested for the gas phase Beckmann rearrangement of cyclohexanone oxime (CHO) into lactam. B ZSM 5 derived titanosilicalite (Ti ZSM 5) exhibits catalytic performances comparable to hydrothermally synthesized titanosilicalite (TS 1), much better than B ZSM 5 and Al ZSM 5. The effect of reaction conditions (solvent, feed space velocity, and water) on the catalytic performance of Ti ZSM 5 is studied. It is found that a quantitative relationship exists among the feed space velocity, the reaction time, and the CHO constant conversion. Ethanol or methanol as solvent shows higher activity, lactam selectivity, and stability than benzene and n hexanol. The addition of water to the rearrangement with a maximum amount of 1.0 mole per mole CHO results in the increase of CHO conversion while no meaningful changes in lactam selectivity and stability are observed.
文摘Silicalite-1 was hydrothermally synthesized in the presence of different concentrations of Na+using tetrapropylammonium hydroxide(TPAOH)as a template.The synthesis was followed by a base treatment.The silicalite-1samples were characterized using X-ray diffrac-tion,scanning electron microscopy,N2 adsorption,X-ray photoelectron spectroscopy,Fourier transform infrared spectroscopy and NH3 temperature-programmed deso-rption.The samples were used as catalysts for the vapor phase Beckmann rearrangement of cyclohexanone oxime.During the synthesis,the sodium ions were incorporated onto the silicalite-1 crystals,but were then removed by the base treatment.All the catalysts exhibited nearly complete conversion of cyclohexanone oxime toε-caprolactam with selectivities grater than 95%.Addition of less than 2.5 mol-%Na^(+)(relative to TPAOH)did not influence the catalytic properties.However,for Na+concentrations≥5 mol-%,the particle sizes of silicalite-1 increased and the catalytic activities decreased,which can be attributed to carbon deposition.The results in this work are of great importance for the polymer industry.
基金financially supported by the National Natural Science Foundation of China (Nos. 21176147, 21276149 and 21204044)Program for Scientifc Research Innovation Team in Colleges and Universities of Shandong Province
文摘A selective reaction of cyclohexanone oxime-blocked tolylene-2,4-diisocyanate（2,4-TDI）with amino siloxane was observed,in which amines were capable of discriminating two reactive groups in the 2,4-TDI molecule.Thus,tolylene-2-tert-butyldimethylsilyloxyethyl carbamide-4-cyclohexanone oxime carbamate was synthesized and its precise structure was determined by single-crystal X-ray diffraction.Moreover,it was found that oxime-blocked isocyanate could react selectively with the–NH2group with the–OH group unprotected in ethanolamine.
