Solid strong base catalysts are highly attractive for diverse reactions owing to their advantages of neglectable corrosion,facile separation,and environmental friendliness.However,their widespread applications are imp...Solid strong base catalysts are highly attractive for diverse reactions owing to their advantages of neglectable corrosion,facile separation,and environmental friendliness.However,their widespread applications are impeded by basic components aggregation and low stability.In this work,we fabricate single calcium atoms on graphene(denoted as Ca1/G)by use of a redox strategy for the first time,producing solid strong base catalyst with high activity and stability.The precursor Ca(NO_(3))_(2)is first reduced to CaO at 400℃ by the support graphene,forming CaO/G with conventional basic sites,and the subsequent reduction at 850℃results in the generation of Ca1/G with atomically dispersed Ca.Various characterizations reveal that Ca single atoms are anchored on graphene in tetra-coordination(Ca-C_(2)-N_(2))where N is in situ doped from Ca(NO_(3))_(2).The atomically dispersed Ca,along with their anchoring on the support,endow Ca1/G with high activity and stability toward the transesterification reaction of ethylene carbonate with methanol.The turnover frequency value reaches 128.0 h^(-1)on Ca1/G,which is much higher than the traditional counterpart CaO/G and various reported solid strong bases(2.9-46.2 h^(-1)).Moreover,the activity of Ca1/G is well maintained during 5 cycles,while 60%of activity is lost for the conventional analogue CaO/G due to the leaching of Ca.展开更多
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
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supported by the National Science Fund for Distinguished Young Scholars(22125804)the National Natural Science Foundation of China(22078155 and 22178163)the National Students'platform for innovation and entrepreneurship training program(20210291013Z).
文摘Solid strong base catalysts are highly attractive for diverse reactions owing to their advantages of neglectable corrosion,facile separation,and environmental friendliness.However,their widespread applications are impeded by basic components aggregation and low stability.In this work,we fabricate single calcium atoms on graphene(denoted as Ca1/G)by use of a redox strategy for the first time,producing solid strong base catalyst with high activity and stability.The precursor Ca(NO_(3))_(2)is first reduced to CaO at 400℃ by the support graphene,forming CaO/G with conventional basic sites,and the subsequent reduction at 850℃results in the generation of Ca1/G with atomically dispersed Ca.Various characterizations reveal that Ca single atoms are anchored on graphene in tetra-coordination(Ca-C_(2)-N_(2))where N is in situ doped from Ca(NO_(3))_(2).The atomically dispersed Ca,along with their anchoring on the support,endow Ca1/G with high activity and stability toward the transesterification reaction of ethylene carbonate with methanol.The turnover frequency value reaches 128.0 h^(-1)on Ca1/G,which is much higher than the traditional counterpart CaO/G and various reported solid strong bases(2.9-46.2 h^(-1)).Moreover,the activity of Ca1/G is well maintained during 5 cycles,while 60%of activity is lost for the conventional analogue CaO/G due to the leaching of Ca.
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.
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.
