A rapid and environmentally friendly approach to synthesize hierarchical sodalite from natural aluminosilicate mineral without the involvement of any mesoporogen or post-synthesis treatment was developed.This strategy...A rapid and environmentally friendly approach to synthesize hierarchical sodalite from natural aluminosilicate mineral without the involvement of any mesoporogen or post-synthesis treatment was developed.This strategy involves three important steps:the first is the depolymerization of an aluminosilicate mineral into highly reactive silicon and aluminum species with ideal meso-scale structures through activation of a sub-molten salt.The second step is the hydrolysis and condensation of the activated aluminosilicate mineral into zeolitic precursors that also have a meso-scale structure.The third is the rapid zeolitization of the zeolitic precursors through the reversed crystal growth route at room temperature and ambient pressure to form hierarchical sodalite.The physicochemical properties of the as-synthesized sodalite were systematically characterized,and the formation mechanism of the hierarchical pore structure was discussed.When used as a solid base catalyst for Knoevenagel condensation,the as-synthesized sodalite and its potassium ion-exchanged product with hierarchical micro-meso-macroporous structure both exhibited high catalytic activity and product selectivity.展开更多
The preparation and regeneration conditions of the identified catalyst X/Y/MgO/?-Al2O3 with high catalytic activity were studied and optimized. The biodiesel was prepared by transesterification of Jatropha curcas see...The preparation and regeneration conditions of the identified catalyst X/Y/MgO/?-Al2O3 with high catalytic activity were studied and optimized. The biodiesel was prepared by transesterification of Jatropha curcas seed oil produced in Guizhou with methanol at its reflux temoerature in the presence of X/Y/MgO/?-Al2O3 . The pilot plant tests were carried out in a 100 L reaction vessel. Both average yield and fatty acid methyl esters (FAME) content reached more than 96.50% under the optimum reaction conditions of the pilot plant tests designed with an oil/methanol molar ratio of 1 : 10, catalyst concentration of 1.00%, and reaction time of 3 h at reflux temperature. In addition, analysis shows that the quality of biodiesel meets the standard EN 14214.展开更多
A facile route for the synthesis of dimethyl adipate (DAP) from cyclopentanone and dimethyl carbonate (DMC) in the presence of solid base catalysts has been developed.It was found that the intermediate carbomethoxycyc...A facile route for the synthesis of dimethyl adipate (DAP) from cyclopentanone and dimethyl carbonate (DMC) in the presence of solid base catalysts has been developed.It was found that the intermediate carbomethoxycyclopentanone (CMCP) was produced from cyclopentanone with DMC in the first step,and then CMCP was further converted to DAP by reacting with a methoxide group.The role of the basic catalysts can be mainly ascribed to the activation of cyclopentanone via the abstraction of a proton in the α-position by base sites,and solid bases with moderate strength,such as MgO,favor the formation of DAP.展开更多
Four kinds of strontium borates were prepared and characterized by XRD,SEM,EDS,TG-DTA and Hammett titration method,and their catalytic activities were examined in the transesterification of glyceryl tributyrate with m...Four kinds of strontium borates were prepared and characterized by XRD,SEM,EDS,TG-DTA and Hammett titration method,and their catalytic activities were examined in the transesterification of glyceryl tributyrate with methanol for the first time.The separate effects of the molar ratio of methanol to oil,the reaction time,and reusability were investigated.In addition,the catalytic activities of Sr(OH)2and SrCO3were also examined for the comparison.The results showed that the basicity and catalytic activity of these catalysts were decreased as the following order:Sr(OH)2>SrB2O4·4H2O>SrB6O10·5H2O>SrB2O4>SrB6O10>SrCO3,and the reusability decreases as the following order:anhydrous strontium borates(SrB2O4,SrB6O10)>hydrated strontium borates(SrB2O4·4H2O,SrB6O10·5H2O)>Sr(OH)2.The results indicate that the SrB2O4·4H2O with regular morphology,which was obtained at low temperature by a simple preparation method,might be as one kind of good potential alkaline earth salts catalyst for transesterification.Moreover,the possible reaction mechanism is proposed and analyzed.展开更多
Recently, increasing interest has been focused on the hydrolysis of carbohydrates to monosaccharides, among which, glucose and xylose as typical platform sugars can be used to produce chemicals and biofuels. As hetero...Recently, increasing interest has been focused on the hydrolysis of carbohydrates to monosaccharides, among which, glucose and xylose as typical platform sugars can be used to produce chemicals and biofuels. As heterogeneous catalysts, solid acids have gained extensive attention for biomass biorefinery and could replace the conventional process owing to their excellent properties, including acceptable acidity and easy separation. In particular, biochar-based solid acids derived from biomass are promising for biomass conversion owing to the low-cost of feedstocks and the simple preparation procedure. Herein, we attempt to provide a critical overview of biochar-based solid acids for hydrolysis of carbohydrates into glucose and xylose. The preparation methods and properties of biochar-based catalysts as well as the influence of their properties on catalytic performance were discussed in detail. We also highlight the major challenges facing the use of biochar-based solid acids for carbohydrate hydrolysis.展开更多
Based on starch and series of alkyl benzene sulfonic acid as the materials, a novel carbon-based solid acid catalyst is synthesized using hydrothermal method. This catalyst exhibits much higher catalytic activity in t...Based on starch and series of alkyl benzene sulfonic acid as the materials, a novel carbon-based solid acid catalyst is synthesized using hydrothermal method. This catalyst exhibits much higher catalytic activity in the reaction of esterification of Mono-fatty alcohol polyoxyethylene maleate esters with 1,4-butanediol. The structure of carbon-based solid acid catalyst was charactered by IR and XRD, characterizations showed that this catalyst exhibited high –SO3H loading. Reusability of the carbon-based solid acid catalyst for esterification showed that after recycling five times the activity remained unchanged.展开更多
KOH/CaO/C supported catalyst was prepared via incipient wetness impregnation and used in synthesis of biodiesel. First, the effects of carrier/active components mass ratio, calcination temperature and calcination time...KOH/CaO/C supported catalyst was prepared via incipient wetness impregnation and used in synthesis of biodiesel. First, the effects of carrier/active components mass ratio, calcination temperature and calcination time on catalytic activity were investigated aiming at biodiesel yield, and the optimal process conditions for preparation of KOH/CaO/C catalysts were: mass ratio of C/CaO was 4:6;KOH solution (mass concentration) was 25%;impregnation time was 24 h;drying temperature was 105°C and time was 4 h;calcination temperature was 500°C and time was 5 h. Then the complex catalysts prepared under the optimal conditions were applied to synthesize biodiesel, and the effects of dose of catalyst, reaction temperature, and reaction time on the yield of biodiesel were investigated. At last, the optimal process conditions for synthesis of biodiesel were concluded: methanol-oil ratio was 10:1;catalyst dose was 2% of that of soybean oil;reaction temperature was 65°C;reaction time was 5 h. The yield of as-prepared biodiesel could be 98%.展开更多
Nano-solid-base catalyst K2O/γ-Al2O3 was prepared and adopted for the synthesis of biodiesel by transesterification of rapeseed oil with methanol. The particle diameter of the catalyst was about 50 nm, which was meas...Nano-solid-base catalyst K2O/γ-Al2O3 was prepared and adopted for the synthesis of biodiesel by transesterification of rapeseed oil with methanol. The particle diameter of the catalyst was about 50 nm, which was measured by transmission electron microscopy （TEM）. The variables affecting the yield of biodiesel during transesterification, such as mass ratio of KNO3 to γ-Al2O3, calcination temperature, calcination time, catalyst content, molar ratio of methanol to oil, reaction temperature and reaction time were investigated. The catalyst obtained by calcining a mixture of KNO3 and γ-Al2O3 （mKNO3/mγ-Al2O3 =70 %） at 600℃ for 3 h, was found to be the optimum one, which gave the highest catalytic activity in the reaction. With 3% （mcatalyst/moil） catalyst, when the transesterification was carried out at a molar ratio of methanol to oil of 12 ： ：1, a reaction temperature of 70℃, and a reaction time of 3 h, yield of 94% was achieved.展开更多
基金The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China(grant Nos.91434206,21506034,and 21276270).
文摘A rapid and environmentally friendly approach to synthesize hierarchical sodalite from natural aluminosilicate mineral without the involvement of any mesoporogen or post-synthesis treatment was developed.This strategy involves three important steps:the first is the depolymerization of an aluminosilicate mineral into highly reactive silicon and aluminum species with ideal meso-scale structures through activation of a sub-molten salt.The second step is the hydrolysis and condensation of the activated aluminosilicate mineral into zeolitic precursors that also have a meso-scale structure.The third is the rapid zeolitization of the zeolitic precursors through the reversed crystal growth route at room temperature and ambient pressure to form hierarchical sodalite.The physicochemical properties of the as-synthesized sodalite were systematically characterized,and the formation mechanism of the hierarchical pore structure was discussed.When used as a solid base catalyst for Knoevenagel condensation,the as-synthesized sodalite and its potassium ion-exchanged product with hierarchical micro-meso-macroporous structure both exhibited high catalytic activity and product selectivity.
基金supported by the Key Science and Technology Project of Guizhou(No.20076004).
文摘The preparation and regeneration conditions of the identified catalyst X/Y/MgO/?-Al2O3 with high catalytic activity were studied and optimized. The biodiesel was prepared by transesterification of Jatropha curcas seed oil produced in Guizhou with methanol at its reflux temoerature in the presence of X/Y/MgO/?-Al2O3 . The pilot plant tests were carried out in a 100 L reaction vessel. Both average yield and fatty acid methyl esters (FAME) content reached more than 96.50% under the optimum reaction conditions of the pilot plant tests designed with an oil/methanol molar ratio of 1 : 10, catalyst concentration of 1.00%, and reaction time of 3 h at reflux temperature. In addition, analysis shows that the quality of biodiesel meets the standard EN 14214.
基金supported by the Zhangjiang Science and Technology Development Foundation of Guangdong,China (2009C3101015)Doctoral Starting Foundation of Guangdong Medical College (XB0811)
文摘A facile route for the synthesis of dimethyl adipate (DAP) from cyclopentanone and dimethyl carbonate (DMC) in the presence of solid base catalysts has been developed.It was found that the intermediate carbomethoxycyclopentanone (CMCP) was produced from cyclopentanone with DMC in the first step,and then CMCP was further converted to DAP by reacting with a methoxide group.The role of the basic catalysts can be mainly ascribed to the activation of cyclopentanone via the abstraction of a proton in the α-position by base sites,and solid bases with moderate strength,such as MgO,favor the formation of DAP.
基金supported by the National Natural Science Foundation of China(21173143)
文摘Four kinds of strontium borates were prepared and characterized by XRD,SEM,EDS,TG-DTA and Hammett titration method,and their catalytic activities were examined in the transesterification of glyceryl tributyrate with methanol for the first time.The separate effects of the molar ratio of methanol to oil,the reaction time,and reusability were investigated.In addition,the catalytic activities of Sr(OH)2and SrCO3were also examined for the comparison.The results showed that the basicity and catalytic activity of these catalysts were decreased as the following order:Sr(OH)2>SrB2O4·4H2O>SrB6O10·5H2O>SrB2O4>SrB6O10>SrCO3,and the reusability decreases as the following order:anhydrous strontium borates(SrB2O4,SrB6O10)>hydrated strontium borates(SrB2O4·4H2O,SrB6O10·5H2O)>Sr(OH)2.The results indicate that the SrB2O4·4H2O with regular morphology,which was obtained at low temperature by a simple preparation method,might be as one kind of good potential alkaline earth salts catalyst for transesterification.Moreover,the possible reaction mechanism is proposed and analyzed.
基金supported by grants from the Program for National Natural Science Foundation of China(No.21576103)the Guangdong Program for Support of Top-notch Young Professionals(No.2016TQ03Z585)the Guangzhou Science and Technology Plan Project(No.201707010059)
文摘Recently, increasing interest has been focused on the hydrolysis of carbohydrates to monosaccharides, among which, glucose and xylose as typical platform sugars can be used to produce chemicals and biofuels. As heterogeneous catalysts, solid acids have gained extensive attention for biomass biorefinery and could replace the conventional process owing to their excellent properties, including acceptable acidity and easy separation. In particular, biochar-based solid acids derived from biomass are promising for biomass conversion owing to the low-cost of feedstocks and the simple preparation procedure. Herein, we attempt to provide a critical overview of biochar-based solid acids for hydrolysis of carbohydrates into glucose and xylose. The preparation methods and properties of biochar-based catalysts as well as the influence of their properties on catalytic performance were discussed in detail. We also highlight the major challenges facing the use of biochar-based solid acids for carbohydrate hydrolysis.
文摘Based on starch and series of alkyl benzene sulfonic acid as the materials, a novel carbon-based solid acid catalyst is synthesized using hydrothermal method. This catalyst exhibits much higher catalytic activity in the reaction of esterification of Mono-fatty alcohol polyoxyethylene maleate esters with 1,4-butanediol. The structure of carbon-based solid acid catalyst was charactered by IR and XRD, characterizations showed that this catalyst exhibited high –SO3H loading. Reusability of the carbon-based solid acid catalyst for esterification showed that after recycling five times the activity remained unchanged.
文摘KOH/CaO/C supported catalyst was prepared via incipient wetness impregnation and used in synthesis of biodiesel. First, the effects of carrier/active components mass ratio, calcination temperature and calcination time on catalytic activity were investigated aiming at biodiesel yield, and the optimal process conditions for preparation of KOH/CaO/C catalysts were: mass ratio of C/CaO was 4:6;KOH solution (mass concentration) was 25%;impregnation time was 24 h;drying temperature was 105°C and time was 4 h;calcination temperature was 500°C and time was 5 h. Then the complex catalysts prepared under the optimal conditions were applied to synthesize biodiesel, and the effects of dose of catalyst, reaction temperature, and reaction time on the yield of biodiesel were investigated. At last, the optimal process conditions for synthesis of biodiesel were concluded: methanol-oil ratio was 10:1;catalyst dose was 2% of that of soybean oil;reaction temperature was 65°C;reaction time was 5 h. The yield of as-prepared biodiesel could be 98%.
基金Supported by the National High-Technology Research and Development Program of China (863 Program) (2007AA100703)
文摘Nano-solid-base catalyst K2O/γ-Al2O3 was prepared and adopted for the synthesis of biodiesel by transesterification of rapeseed oil with methanol. The particle diameter of the catalyst was about 50 nm, which was measured by transmission electron microscopy （TEM）. The variables affecting the yield of biodiesel during transesterification, such as mass ratio of KNO3 to γ-Al2O3, calcination temperature, calcination time, catalyst content, molar ratio of methanol to oil, reaction temperature and reaction time were investigated. The catalyst obtained by calcining a mixture of KNO3 and γ-Al2O3 （mKNO3/mγ-Al2O3 =70 %） at 600℃ for 3 h, was found to be the optimum one, which gave the highest catalytic activity in the reaction. With 3% （mcatalyst/moil） catalyst, when the transesterification was carried out at a molar ratio of methanol to oil of 12 ： ：1, a reaction temperature of 70℃, and a reaction time of 3 h, yield of 94% was achieved.
