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In the process of preparing biodiesel using microreactors, cosolvents and homogeneous catalysts are generally used, which adds to the separation cost. Hence, this study explored the use of an opposite-side feed micro-fixed-bed reactor with an inner diameter of 2 mm to produce biodiesel by the transesterification of soybean oil and methanol without any cosolvent, in which a fixed solid base acted as catalyst and obstacles. A biodiesel yield of 99.4% was achieved when the methanol-to-oil molar ratio was 12, the temperature was 70 °C, and the residence time was 8.05 min. A mixing study was conducted for this microreactor through computational fluid dynamics (CFD) simulations. The results showed that the best mixing index could reach 0.94 within 25 mm (length). Then, the transesterification kinetics in this reactor were found to be consistent with the proposed pseudo-homogeneous secondary reaction model. With the kinetics data and mixed-model, the biodiesel yield could be predicted. The simulated results were consistent with the experimental data. [ABSTRACT FROM AUTHOR]

Herein, a kind of three-dimensional hollow Mg-Ca-Al hydrotalcite-like compounds (HTLCs) microsphere was prepared by self-assembly of hydrotalcite-like nanosheets. Mg-Ca-Al HTLCs microsphere (MS) has large specific surface area and large pore size, and the modification of KF·2H2O increases numerous alkaline active sites on the surface of the catalyst. The prepared catalyst has excellent catalytic effect for the production of biodiesel by transesterification. Under the optimal conditions of the catalyst addition amount which accounts for 2% of the weight of oil, the biodiesel yield of the best catalyst is as high as 92% within 30 minutes. This article also provides a paradigm of a rational structural design for regulating the morphology of HTLCs. [ABSTRACT FROM AUTHOR]

A mathematical model based on the pore model of membrane, liquid–liquid equilibrium model and reaction kinetics model for biodiesel production in membrane reactor was developed. The parameters of the model were calculated from the membrane reaction process of the transesterification between soybean oil and methanol catalyzed by KF/Ca-Mg-Al hydrotalcite. The biodiesel yield calculated by the model fitted the experimental data well. The model simulated results indicated that the membrane reaction system can be divided in biodiesel accumulation and membrane separation of biodiesel stage. In the studied temperature range, the biodiesel yield with the same reaction time increased with the increase in temperature. However, the maximum yields under of all temperatures were almost the same. The results proved that the membrane reactor can shift the transesterification equilibrium to the products side by continuously removing the products. [ABSTRACT FROM AUTHOR]

In this study, Ca–Mg–Al hydrotalcite was deposited on the inert honeycomb ceramic surface as a second carrier and KF was loaded on the support as an active component. The KF/Ca–Mg–Al hydrotalcite/honeycomb ceramic monolithic catalyst was packed in the membrane reactor for biodiesel production from the transesterification between soybean oil and methanol. The central composite design (CCD) of response surface methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst amount and circulation velocity on the production of biodiesel. A quadratic model was developed to navigate the design space. The optimum condition for the highest biodiesel yield was obtained by the assistance of the model. The catalyst showed a reasonable efficiency and reusability for coupling the monolithic catalyzed transesterification and membrane separation in the membrane reactor. [ABSTRACT FROM AUTHOR]

During transesterification process in the fixed-bed reactor, traditional heterogeneous catalyst cannot stand the high pressure drop and would easily breaks at the reactor bottom thus blocking the outlets. KF/γ-Al 2 O 3 /honeycomb ceramic (HC) monolithic catalyst which was prepared in this research can be utilized because of its thermal and mechanical stability. γ-Al 2 O 3 was deposited on the inert HC surface as a second carrier and KF acted as an active component. Loading ratio and loading intensity were both examined in order to select for catalyst with best catalytic performance. Optima reaction condition in the fixed-bed reactor was studied by investigating the effect of residence time, methanol/oil molar ratio and reaction temperature on oil conversion. Experiment results indicated that when the residence time was 33 min, the methanol/oil molar ratio was 18:1, the reaction temperature was 140 °C and with saturated vapor pressure, oil conversion could exceed 96%. X-ray diffraction (XRD) and scanning electron microscope (SEM) indicated that the KF/γ-Al 2 O 3 /HC monolithic catalyst shared the same alkaline catalytic centers identical to KF/γ-Al 2 O 3 . [ABSTRACT FROM AUTHOR]

Highlights: [•] Solid acid catalysis and membrane separation was coupled for biodiesel production. [•] PTSA/MCM-41 was used as a catalyst for biodiesel production in a membrane reactor. [•] Box–Behnken design was employed to analyze and optimize the process. [ABSTRACT FROM AUTHOR]

A 500 h endurance test of continuous catalytic transesterificationto biodiesel was conducted in a bench-scale fixed-bed reactor. A designedcylinder shape of KF/Ca–Mg–Al hydrotalcite catalystwas stable through the test with high catalytic activity and mechanicalstrength, converting palm oil to biodiesel with a conversion of morethan 95%. Conditions effects on transesterification under relativehigh pressure (1.0 MPa) were investigated and a one-dimensional heterogeneousmodel of a fixed-bed reactor was developed to describe the reaction-masstransfer behaviors of continuous catalytic transesterification ina bench-scale fixed-bed reactor. With the given reactor size, optimumconditions were proposed as a LHSV (liquid hourly space velocity)of 0.76–0.25 h–1, molar ratio of methanol-to-oilof 9.16–13.7, and temperature of 338–347 K. [ABSTRACT FROM AUTHOR]

ABSTRACT Biodiesel has been drawing a great deal of attention on account of its special environment friendly and fuel properties. However, the cost of biodiesel production is still very high compared with that of traditional fossil fuels. In this study, a heterogeneous super acid catalyst and inedible oil were used to reduce the cost of raw materials. Biodiesel was obtained from cotton seed oil (CSO) and catalyzed by the super acid SO42−/ZrO2, which was prepared by impregnation and characterized by infrared spectroscopy, thermo-gravimetric analysis (TGA) and X-ray diffraction (XRD). Different operation parameters of the transesterification of CSO with methanol, such as methanol/oil molar ratio, catalyst amount and loaded mass ratio, reaction time and temperature, were investigated. Under the optimum conditions of methanol to CSO molar ratio of 9:1, 3.5 wt% fresh catalyst (loaded mass ratio is 0.841), 1 h reaction time and reaction temperature of 120 °C, a relatively high biodiesel yield of 98% was obtained. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Biodiesel has been drawing a great deal of attention on account of its special environment friendly and fuel properties. However, the cost of biodiesel production is still very high compared with that of traditional fossil fuels. In this study, a heterogeneous super acid catalyst and inedible oil were used to reduce the cost of raw materials. Biodiesel was obtained from cotton seed oil (CSO) and catalyzed by the super acid SO42−/ZrO2, which was prepared by impregnation and characterized by infrared spectroscopy, thermo-gravimetric analysis (TGA) and X-ray diffraction (XRD). Different operation parameters of the transesterification of CSO with methanol, such as methanol/oil molar ratio, catalyst amount and loaded mass ratio, reaction time and temperature, were investigated. Under the optimum conditions of methanol to CSO molar ratio of 9:1, 3.5 wt% fresh catalyst (loaded mass ratio is 0.841), 1 h reaction time and reaction temperature of 120 °C, a relatively high biodiesel yield of 98% was obtained. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: The solid base catalyst KF/Ca–Al hydrotalcite was obtained from Ca–Al layered double hydroxides and successfully used in the transesterification of methanol with palm oil to produce biodiesel. With the load of KF, the activity of Ca–Al mixed-oxides had been improved much. For the mass ratio 80wt.%(KF·6H2O to Ca–Al mixed-oxides) catalyst, under the optimal condition: 338K, catalyst amount 5%(wt./wt. oil) and methanol/oil molar ratio 12:1, after 5h reaction, the fatty acid methyl esters yield could reach 97.98%; for the mass ratio 100wt.%(KF·6H2O to Ca–Al mixed-oxides) ones, under the same reaction condition, only needed 3h to get the FAME yield of 99.74%, and even only reacted 1h, the FAME yield could obtain 97.14%. [Copyright &y& Elsevier]

An efficient, convenient, and environmentally friendly method was developed for the transesterification of glycols into cyclic carbonates catalysed by 5 wt% KF/Ca-Mg-Al hydrotalcite. Using as a model the reaction of glycerol with dimethyl carbonate (DMC), various parameters such as molar ratios, catalyst type and amount, reaction temperature and solvent were studied to optimise the reaction. Then, using the optimal conditions, the formation of the corresponding cyclic carbonates via transesterification of ethylene, propylene and styrene glycols with DMC using KF/Ca-Mg-Al hydrotalcite as solid base catalyst were achieved in good to high yields in short reaction times. The catalyst was conveniently separated and reused for ten cycles without appreciable decrease in its activity. [ABSTRACT FROM AUTHOR]

An abstract of the article "An Efficient and Green Transesterification of Glycols into Cyclic Carbonates Catalyzed by KF/Ca-Mg-Al Hydrotalcite" by Mei Hong and colleagues is presented.