为了开发出更加温和高效的EO氢甲酯化催化剂,用于合成3-羟基丙酸甲酯,在100 m L的反应釜中考察了不同催化体系下环氧乙烷的氢甲酯化反应。探讨了催化剂种类、配体、反应温度、催化剂用量、反应压力、溶剂、助剂等因素对反应的影响,得到...为了开发出更加温和高效的EO氢甲酯化催化剂,用于合成3-羟基丙酸甲酯,在100 m L的反应釜中考察了不同催化体系下环氧乙烷的氢甲酯化反应。探讨了催化剂种类、配体、反应温度、催化剂用量、反应压力、溶剂、助剂等因素对反应的影响,得到了以MeOH作溶剂,摩尔分数2%Co2（CO）8作催化剂,摩尔分数3%胺基酚作配体的催化体系。在4.1 MPa和50-55℃下反应4 h得到的反应转化率与选择性分别为90.8%和91.0%,这是迄今最为温和条件的环氧乙烷氢甲酯化催化体系之一。展开更多
Aim To synthesize naturally occurring (-) methyl2,2-dimethyl-3-hydroxychromanyl-6-formate. Methods Sharpless' asymmetric dihydroxylation wasemployed to construct the 3-hydroxychroman. Results First asymmetric synt...Aim To synthesize naturally occurring (-) methyl2,2-dimethyl-3-hydroxychromanyl-6-formate. Methods Sharpless' asymmetric dihydroxylation wasemployed to construct the 3-hydroxychroman. Results First asymmetric synthesis of (-) methyl 2,2-dimethyl-3-hydroxychromanyl-6-formate (1) was accomplished starting from methyl 4-hydroxy-benzoate(2), and the absolute configuration was established. Conclusion A useful method for constructingchiral 3-hydroxychroman by employing Sharpless' asymmetric dihydroxylation is achieved.展开更多
A series of indium oxide‐modified Cu/SiO2catalysts were synthesized and used to produce ethanol via methyl acetate hydrogenation.In‐Cu/SiO2catalyst containing1.0wt%In2O3exhibited the best catalytic activity and stab...A series of indium oxide‐modified Cu/SiO2catalysts were synthesized and used to produce ethanol via methyl acetate hydrogenation.In‐Cu/SiO2catalyst containing1.0wt%In2O3exhibited the best catalytic activity and stability.The physicochemical properties of the synthesized catalysts were investigated using several characterization methods and the results showed that introducing suitable indium to Cu/SiO2increased the copper dispersion,diminished the copper crystallite size,and enriched the surface Cu+concentration.Furthermore,the Cu/SiO2catalyst gradually deactivated during the stability test,which was mainly attributed to copper sintering and the valence change in surface copper species.In contrast,indium addition can inhibit the thermal transmigration and accumulation of copper nanoparticles to stabilize the catalyst.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.展开更多
Hydroalkoxycarbonylation of olefins has been considered to be one of the most attractive methods to synthesize esters. Controlling the regioselectivities of linear esters(L) and branched esters(B) is a challenging pro...Hydroalkoxycarbonylation of olefins has been considered to be one of the most attractive methods to synthesize esters. Controlling the regioselectivities of linear esters(L) and branched esters(B) is a challenging project for researchers working in this reaction. Although most of the attention has been paid to control the regioselectivity through ligand design in homogeneous catalytic systems, study in the area is still limited. Herein, Ru-clusters/CeO2 is employed as a heterogeneous catalyst for the hydromethoxycarbonylation of styrene without any additives. After optimization of the reaction conditions, the conversion of styrene is > 99% with 83% and 12% regioselectivity of linear and branched ester, respectively. By using different supports(CeO2(nanoparticle), CeO2-rod, and CeO2-cube), three catalysts including Ru-clusters/CeO2, Ru/CeO2-rod, and Ru/CeO2-cube are prepared and applied in the reaction. Structural characterizations demonstrate that the L/B ratio is related to the Ru size of supported Ru catalysts. Further Raman characterization and NH3-TPD demonstrate that the metal-support interaction and the concentration of oxygen vacancy of the catalyst have a great influence on the Ru size. The mechanism and kinetic analysis for this reaction are also investigated in this work.展开更多
In order to evaluate the role of vanadium in the hydrogenation (HYD) reaction, a series of alumina supported vanadium catalysts were prepared and characterized by SEM, XRD, Raman spectrometry, 51V NMR, XPS, as well as...In order to evaluate the role of vanadium in the hydrogenation (HYD) reaction, a series of alumina supported vanadium catalysts were prepared and characterized by SEM, XRD, Raman spectrometry, 51V NMR, XPS, as well as TPR analyses. The catalytic performance of vanadium in HYD of model molecules (naphthalene) and real feedstock (Kuwait atmospheric residue) was studied after sulfidation of the catalysts. It can be concluded that the HYD capabilities of V/Al2O3 catalysts are lower than that of conventional NiMo/Al2O3 catalyst (RefNiMo). The V/Al2O3 catalysts can only facilitate hydrogenation of the first ring of naphthalene, but have little effect on the further hydrogenation of tetralin. Owing to the different forms of metals and sulfur compounds in residue, the weak HYD activity of V/Al2O3 catalysts is able to facilitate the HDM reaction of the residue, albeit with a slight effect on HDS activity.展开更多
The epoxidation of methyl oleate(MO)was conducted in the presence of aqueous H2O2 as the oxidant and hierarchical TS-1(HTS-1)as the catalyst;the catalyst was synthesized using polyquaternium-6 as the mesopore template...The epoxidation of methyl oleate(MO)was conducted in the presence of aqueous H2O2 as the oxidant and hierarchical TS-1(HTS-1)as the catalyst;the catalyst was synthesized using polyquaternium-6 as the mesopore template.The effects of various parameters,i.e.,H2O2/C=C molar ratio,oxidant concentration,amount of the catalyst,reaction temperature,and time,were systematically studied.Furthermore,response surface methodology(RSM)was used to optimize the conditions to maximize the yield of epoxy MO and to evaluate the significance and interplay of the factors affecting the epoxy MO production.The H2O2/C=C molar ratio and catalyst amount were the determining factors for MO epoxidation,wherein the maximum yield of epoxy MO reached 94.9%over HTS-1 under the optimal conditions.展开更多
文摘为了开发出更加温和高效的EO氢甲酯化催化剂,用于合成3-羟基丙酸甲酯,在100 m L的反应釜中考察了不同催化体系下环氧乙烷的氢甲酯化反应。探讨了催化剂种类、配体、反应温度、催化剂用量、反应压力、溶剂、助剂等因素对反应的影响,得到了以MeOH作溶剂,摩尔分数2%Co2（CO）8作催化剂,摩尔分数3%胺基酚作配体的催化体系。在4.1 MPa和50-55℃下反应4 h得到的反应转化率与选择性分别为90.8%和91.0%,这是迄今最为温和条件的环氧乙烷氢甲酯化催化体系之一。
基金This research work was financially supported by the National Natural Science Foundation of China(Grant NO.20272020).
文摘Aim To synthesize naturally occurring (-) methyl2,2-dimethyl-3-hydroxychromanyl-6-formate. Methods Sharpless' asymmetric dihydroxylation wasemployed to construct the 3-hydroxychroman. Results First asymmetric synthesis of (-) methyl 2,2-dimethyl-3-hydroxychromanyl-6-formate (1) was accomplished starting from methyl 4-hydroxy-benzoate(2), and the absolute configuration was established. Conclusion A useful method for constructingchiral 3-hydroxychroman by employing Sharpless' asymmetric dihydroxylation is achieved.
文摘A series of indium oxide‐modified Cu/SiO2catalysts were synthesized and used to produce ethanol via methyl acetate hydrogenation.In‐Cu/SiO2catalyst containing1.0wt%In2O3exhibited the best catalytic activity and stability.The physicochemical properties of the synthesized catalysts were investigated using several characterization methods and the results showed that introducing suitable indium to Cu/SiO2increased the copper dispersion,diminished the copper crystallite size,and enriched the surface Cu+concentration.Furthermore,the Cu/SiO2catalyst gradually deactivated during the stability test,which was mainly attributed to copper sintering and the valence change in surface copper species.In contrast,indium addition can inhibit the thermal transmigration and accumulation of copper nanoparticles to stabilize the catalyst.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.
文摘Hydroalkoxycarbonylation of olefins has been considered to be one of the most attractive methods to synthesize esters. Controlling the regioselectivities of linear esters(L) and branched esters(B) is a challenging project for researchers working in this reaction. Although most of the attention has been paid to control the regioselectivity through ligand design in homogeneous catalytic systems, study in the area is still limited. Herein, Ru-clusters/CeO2 is employed as a heterogeneous catalyst for the hydromethoxycarbonylation of styrene without any additives. After optimization of the reaction conditions, the conversion of styrene is > 99% with 83% and 12% regioselectivity of linear and branched ester, respectively. By using different supports(CeO2(nanoparticle), CeO2-rod, and CeO2-cube), three catalysts including Ru-clusters/CeO2, Ru/CeO2-rod, and Ru/CeO2-cube are prepared and applied in the reaction. Structural characterizations demonstrate that the L/B ratio is related to the Ru size of supported Ru catalysts. Further Raman characterization and NH3-TPD demonstrate that the metal-support interaction and the concentration of oxygen vacancy of the catalyst have a great influence on the Ru size. The mechanism and kinetic analysis for this reaction are also investigated in this work.
基金supported by the National Basic Research Program of China(973 Program No.2012CB224802)
文摘In order to evaluate the role of vanadium in the hydrogenation (HYD) reaction, a series of alumina supported vanadium catalysts were prepared and characterized by SEM, XRD, Raman spectrometry, 51V NMR, XPS, as well as TPR analyses. The catalytic performance of vanadium in HYD of model molecules (naphthalene) and real feedstock (Kuwait atmospheric residue) was studied after sulfidation of the catalysts. It can be concluded that the HYD capabilities of V/Al2O3 catalysts are lower than that of conventional NiMo/Al2O3 catalyst (RefNiMo). The V/Al2O3 catalysts can only facilitate hydrogenation of the first ring of naphthalene, but have little effect on the further hydrogenation of tetralin. Owing to the different forms of metals and sulfur compounds in residue, the weak HYD activity of V/Al2O3 catalysts is able to facilitate the HDM reaction of the residue, albeit with a slight effect on HDS activity.
基金supported by the Evonik Industries AGthe Program for New Century Excellent Talents in University(NCET-04-0270)~~
文摘The epoxidation of methyl oleate(MO)was conducted in the presence of aqueous H2O2 as the oxidant and hierarchical TS-1(HTS-1)as the catalyst;the catalyst was synthesized using polyquaternium-6 as the mesopore template.The effects of various parameters,i.e.,H2O2/C=C molar ratio,oxidant concentration,amount of the catalyst,reaction temperature,and time,were systematically studied.Furthermore,response surface methodology(RSM)was used to optimize the conditions to maximize the yield of epoxy MO and to evaluate the significance and interplay of the factors affecting the epoxy MO production.The H2O2/C=C molar ratio and catalyst amount were the determining factors for MO epoxidation,wherein the maximum yield of epoxy MO reached 94.9%over HTS-1 under the optimal conditions.
