Biodiesel industrial production based on a solid base catalyst in a fixed-bed was simulated. The lab and bench scale experiments were carded out effectively, in which the kinetic model is established and it can descri...Biodiesel industrial production based on a solid base catalyst in a fixed-bed was simulated. The lab and bench scale experiments were carded out effectively, in which the kinetic model is established and it can describe the transesterification reaction well. The Antoine equation of biodiesel is regressed with the vapor-liquid data cited of literature. The non-random two liquid （NRTL） model is applied to describe the system of fatty acid methyl ester （FAME）, methanol and glycerol and parameters are obtained. The Ternary phase map is obtained from Aspen Plus via the liquid-liquid equilibrium （LLE） data. In order to describe the production in a fixed-bed performs in industrial scale after being magnified 1 000 times, the Aspen Plus simulation is employed, where two flowsheets are simulated to predict material and energy consumption. The simulation results prove that at least 350. 42 kW energy consumption can be reduced per hour to produce per ton biodiesel compared with data reported in previous references.展开更多
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
A facile route for the synthesis of dimethyl adipate （DAP） from cyclopentanone and dimethyl carbonate （DMC） in the pres- ence of solid base catalysts has been developed. It was found that the intermediate carbomet...A facile route for the synthesis of dimethyl adipate （DAP） from cyclopentanone and dimethyl carbonate （DMC） in the pres- ence 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 a-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 wit...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）2 and SrCO3 were 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 （SrBgO4, SrB6O10） 〉 hydrated strontium borates （SrB2O4·4H2O, SrB6O10·5H2O） 〉 Sr（OH）〉 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
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
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
Solid strong base catalysts have high potentials in a variety of reactions due to the advantages of negligible corrosion,easy separation,and high efficiency.However,two issues hinder the applications of such catalysts...Solid strong base catalysts have high potentials in a variety of reactions due to the advantages of negligible corrosion,easy separation,and high efficiency.However,two issues hinder the applications of such catalysts seriously,namely aggregation of basic sites and leaching of active species during reactions.The development of solid strong base catalysts with active sites that are highly dispersed and stable remains a pronounced challenge.In this work,we employed a two-step reduction strategy to anchor Na single atoms on nitrogen-doped porous carbon(NPC)support,producing a high-performance solid strongly basic catalyst named as Na1/NPC.The alkali precursor NaNO3was converted to Na_(2)O on NPC at 400℃,in which conventional solid base catalyst Na_(2)O/NPC was generated.Upon heat treatment at 850oC,Na_(2)O was further reduced to Na single atoms anchored on NPC,creating Na1/NPC.Experimental studies and theoretical calculations show that Na is structurally embedded on the support in penta-coordinated configuration(Na-C_(3)N_(2)).The synergistic effect of highly dispersed Na atoms and nitrogen doping results in uncommon catalytic activity and stability.In transesterification between methanol and ethylene carbonate to produce dimethyl carbonate(DMC),the yield of DMC reaches 48.4%over Na1/NPC,corresponding to a turnover frequency(TOF)of 129.4 h^(-1),which is far beyond the conventional counterpart Na_(2)O/NPC(63.3 h^(-1))and various reported solid base catalysts.The catalytic activity of Na1/NPC almost keeps constant during five cycles,while 87%of activity is lost for Na_(2)O/NPC due to the leaching of basic sites.This work might offer new ideas for the development of efficient single-atom solid strong base catalysts with high efficiency.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
基金The National Basic Research Program of China(973Program)(No.2010CB732206)the National Natural Science Foundation of China(No.21076044,21276050)
文摘Biodiesel industrial production based on a solid base catalyst in a fixed-bed was simulated. The lab and bench scale experiments were carded out effectively, in which the kinetic model is established and it can describe the transesterification reaction well. The Antoine equation of biodiesel is regressed with the vapor-liquid data cited of literature. The non-random two liquid （NRTL） model is applied to describe the system of fatty acid methyl ester （FAME）, methanol and glycerol and parameters are obtained. The Ternary phase map is obtained from Aspen Plus via the liquid-liquid equilibrium （LLE） data. In order to describe the production in a fixed-bed performs in industrial scale after being magnified 1 000 times, the Aspen Plus simulation is employed, where two flowsheets are simulated to predict material and energy consumption. The simulation results prove that at least 350. 42 kW energy consumption can be reduced per hour to produce per ton biodiesel compared with data reported in previous references.
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 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 pres- ence 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 a-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）2 and SrCO3 were 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 （SrBgO4, SrB6O10） 〉 hydrated strontium borates （SrB2O4·4H2O, SrB6O10·5H2O） 〉 Sr（OH）〉 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 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 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.
基金supported by the National Science Foundation of China(22125804 and U24A20534)。
文摘Solid strong base catalysts have high potentials in a variety of reactions due to the advantages of negligible corrosion,easy separation,and high efficiency.However,two issues hinder the applications of such catalysts seriously,namely aggregation of basic sites and leaching of active species during reactions.The development of solid strong base catalysts with active sites that are highly dispersed and stable remains a pronounced challenge.In this work,we employed a two-step reduction strategy to anchor Na single atoms on nitrogen-doped porous carbon(NPC)support,producing a high-performance solid strongly basic catalyst named as Na1/NPC.The alkali precursor NaNO3was converted to Na_(2)O on NPC at 400℃,in which conventional solid base catalyst Na_(2)O/NPC was generated.Upon heat treatment at 850oC,Na_(2)O was further reduced to Na single atoms anchored on NPC,creating Na1/NPC.Experimental studies and theoretical calculations show that Na is structurally embedded on the support in penta-coordinated configuration(Na-C_(3)N_(2)).The synergistic effect of highly dispersed Na atoms and nitrogen doping results in uncommon catalytic activity and stability.In transesterification between methanol and ethylene carbonate to produce dimethyl carbonate(DMC),the yield of DMC reaches 48.4%over Na1/NPC,corresponding to a turnover frequency(TOF)of 129.4 h^(-1),which is far beyond the conventional counterpart Na_(2)O/NPC(63.3 h^(-1))and various reported solid base catalysts.The catalytic activity of Na1/NPC almost keeps constant during five cycles,while 87%of activity is lost for Na_(2)O/NPC due to the leaching of basic sites.This work might offer new ideas for the development of efficient single-atom solid strong base catalysts with high efficiency.
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%.
