Alkali Hydrothermal Synthesis of Na0.1Ca0.9TiO3 Nanorods as Heterogeneous Catalyst for Transesterification of Camelina Sativa Oil to Biodiesel

Orthorhombic perovskite Na_0.1Ca_0.9TiO₃ nanorods were synthesized at low calcination temperature via alkali hydrothermal synthesis. The synthesized nanorods exhibits a square based prism morphology, with a width and length of 200–500 nm and 2–3 μm respectively. The structural, textural and basic characteristics of the catalyst were examined by SEM, TEM, XRD and BET. The growth direction of the nanorods was confirmed to be along the long symmetry [110] zone axis and the exterior surfaces are found to be polar (110) and (002) with either Ti or Ca exposed in those facets. The catalytic activity of the nanorods was investigated for the transesterification of the low-input Camelina Sativa oil and methanol to give the fatty acid methyl ester (FAME). Effects of important reaction parameters such as methanol to oil molar ratio, catalyst dosage, reaction temperature and reaction time on oil conversion were examined. Optimized biodiesel yield of 93 % was achieved with catalyst dosage of 6 % w/w, methanol to oil molar ratio of 36:1 at reaction temperature of 60 °C for 8 h.     

大麻籽油合成生物柴油

大麻籽油;甲醇;甲酯化;生物柴油;酯交换     

Al2O3掺杂SO2-4/SnO2固体酸催化剂上的酯化和酯交换反应

用共沉淀法制备了一系列不同Al2O3掺杂量(0.5%-3.0%, 摩尔分数)的SO2-4/SnO2催化剂. 采用N2吸附、热重(TG)分析、X射线粉末衍射(XRD)、X射线光电子能谱(XPS)、漫反射红外光谱(DRIFTS)、拉曼(Raman)光谱、魔角旋转固体核磁共振(27Al MAS NMR)对催化剂的结构和织构性质进行了表征, 用正丁胺电位滴定法测定了催化剂的酸量, 并评价了这些催化剂对月桂酸与甲醇的酯化和三乙酸甘油酯与甲醇的酯交换反应性能. 实验结果表明SO2-4/SnO2催化剂中掺杂少量Al2O3能明显提高催化活性, 这是由催化剂的酸性位增加而引起的, 添加Al2O3的摩尔分数为1.0%的催化剂表现出最高的反应活性, 在酯化反应中6 h后月桂酸转化率高达92.7%, 在酯交换反应中8 h后三乙酸甘油酯转化率高达91.1%.     

Synthesis of biodiesel over ZnO/Ca(OH)2/KF catalyst prepared by the grinding method

A novel ZnO/Ca(OH)₂/KF solid base catalyst was prepared by the grinding method and applied to biodiesel synthesis by the transesterification of soybean oil. The effect of various parameters such as KF molar amount, calcination temperature, the amount of catalyst, molar ratio of methanol to oil, reaction temperature, and time on the activity of the catalyst were investigated. The catalysts were characterized by several techniques of thermogravimetry/derivative thermogravimetry, X–ray diffraction, Hammett indicator method, and scanning electron microscopy. The analysis results indicated that the KF interacted with Ca(OH)₂ and formed KCaF₃ phase before calcination of the catalyst. The formed KCaF₃ crystal phase was the main catalytic active component for the catalyst activity. In addition, the basicity of ZnO/Ca(OH)₂/KF was greatly influenced by the different calcination temperates, and the catalyst activity was correlated closely with the basicity. A desired biodiesel yield of 97.6 % was obtained at catalyst amount of 3 %, methanol/oil of 12:1, and reaction time of 1.5 h at 65 °C.     

Montmorillonite-supported KF/CaO: a new solid base catalyst for biodiesel production

Biodiesel is an alternative to petroleum-derived diesel fuel; development of a high-efficiency base catalyst to be used in heterogeneous biodiesel production is still a challenge. In this paper, a novel solid base catalyst, KF- and CaO-supported montmorillonite (KCa/MMT) was successfully synthesized by a facile impregnation method, and used for producing biodiesel in transesterification of commercial soybean oil with methanol. The catalysts were characterized by X-ray diffraction, carbon dioxide temperature-programmed desorption and scanning electron microscopy. Effects of the parameters, such as the loading amount of KF, the amount of KCa/MMT, and the methanol to oil molar ratios, on the yield of biodiesel were investigated. A maximum biodiesel yield of 98 % was obtained under the optimal reaction conditions. The separated catalyst can be directly used in the next round of reactions and gave a satisfactory yield. Furthermore, analysis of the catalyst's tolerance to oil-containing water or free fatty acids, and a kinetic study were also carried out. Koros–Nowak tests were designed and conducted, and it was proven that the heat and mass transfer were not limited by the reaction rate.     

Density functional theory study of the reactivity and electronic structure of the transesterification of triacetin in biodiesel production via a sulfated zirconia heterogeneous catalysis

This DFT study examined the interaction of a sulfated zirconia (SZ) slab model system (heterogeneous catalyst) and triacetin (a precursor in biodiesel production) using explicit methanol solvent molecules. Full geometry optimizations of the systems were performed at the B3LYP level of theory. Gibbs free energies provide insight into the spontaneity of the reactions along a three‐step reaction mechanism for the transesterification of triacetin. Charge decomposition analysis revealed electronic charge transfer between the metallic oxide and the organic moieties involved in the reaction mechanism. Fukui indices indicate the likely locations on the SZ surface where catalysis may occur. The quadratic synchronous transit scheme was used to locate transition structures for each step of the transesterification process. The results are in agreement with the strongly acidic catalytic character of zirconium observed experimentally in the production of biodiesel. © 2016 Wiley Periodicals, Inc.     

A New Process for Synthesis of Dimethyl Carbonate from Ethylene Carbonate and Methanol without any Catalyst under Supercritical Conditions

Dimethyl carbonate was synthesized by transesterification reaction between ethylene carbonate and methanol under supercritical conditions without any catalyst. Experimental results showed that the residence time and the molar ratio of methanol to ethylene carbonate all can affect the conversion of ethylene carbonate. When the molar ratio of methanol to ethylene carbonate was 8:1, 81.2% conversion can be achieved at 9.0 MPa and 250℃ after 8 h.     

Fatty acid methyl ester production from acid oil using silica sulfuric acid: Process optimization and reaction kinetics

Conversion of high free fatty acids (FFA) containing acid oil (AO) to fatty acid methyl esters (FAME) using silica sulfuric acid (SSA) as a solid acid catalyst was investigated. Process parameters such as reaction temperature, reaction time, catalyst loading, and methanol to oil molar ratio were optimized using the Taguchi orthogonal array method. Maximum FFA conversion (97.16 %) was achieved under the optimal set of parameter values viz. 70°C, 4 mass % catalyst loading, and 1: 15 oil to methanol molar ratio after 90 min. SSA was reused three times successfully without a significant loss in activity. Biodiesel produced from AO met the international biodiesel standards. Determination of kinetic parameters proved that the experimental results fit the pseudo first order kinetic law.     

Soybean biodiesel methyl esters,free glycerin and acid number quantification by 1H nuclear magnetic resonance spectroscopy

Production of alternative fuels, such as biodiesel, from transesterification of vegetable oil driven by heterogeneous catalysts is a promising alternative to fossil diesel. However, achieving a successful substitution for a new renewable fuel depends on several quality parameters. ¹H NMR spectroscopy was used to determine the amount of methyl esters, free glycerin and acid number in the transesterification of soybean oil with methanol in the presence of hydrotalcite‐type catalyst to produce biodiesel. Reaction parameters, such as temperature and time, were used to evaluate soybean oil methyl esters rate conversion. Temperatures of 100 to 180 °C and times of 20 to 240 min were tested on a 1 : 12 molar ratio soybean oil/methanol reaction. At 180 °C/240 min conditions, a rate of 94.5 wt% of methyl esters was obtained, where free glycerin and free fatty acids were not detected. Copyright © 2012 John Wiley & Sons, Ltd.     

两相溶剂萃取黄连木籽油制备生物柴油

以黄连木籽为原料,采用乙醇/异己烷两相不互溶溶剂对其进行萃取处理.考察了乙醇／异己烷体积比、萃取温度和萃取时间对萃取过程的影响.通过实验确定最佳的萃取条件为,黄连木仁粉50 g,乙醇异己烷总体积300 mL,乙醇/异己烷体积比为50∶50,萃取温度40℃,萃取时间30 min.在此条件下,黄连木籽油出油率达到99.5％...     

Production of biodiesel through transesterification of soybean oil using ZIF-8@GO doped with sodium and potassium catalyst

One pot encapsulating (hydrothermal) method was used to synthesize ZIF-8@GO hybrid nanocomposites. Na/ZIF-8@GO doped with potassium were synthesized by the hydrothermal treatment of ZIF-8@GO precursor with a 10 M alkali solution containing both NaOH and KOH. The final product (KNa/ZIF-8@GO) was characterized by FTIR, XRD, BET, TGA, and SEM. The structure of graphene oxide remains intact following various modifications, as shown by absorption–desorption analysis, while spectral techniques indicate successful immobilization of the neat ZIF-8 between the GO sheets. Furthermore, soybean oil has been used as the feedstock in the preparation of biodiesel by KNa/ZIF-8@GO-catalyzed transesterification process. The effects of various reaction parameters, including methanol/oil molar ratio, reaction time, catalyst mass, and reaction temperature were investigated. A remarkable conversion of 98% was obtained using a 8% (wt/wt oil) of KNa/ZIF-8@GO catalyst, methanol/oil molar ratio of 18 : 1, and reflux temperature of methanol over a period of 8 h. The solid catalyst can be reused over at least three cycles under mild reaction conditions.

     

CaO-MgO@CoFe_2O_4磁性固体碱的制备及其大豆油酯交换反应催化性能

以草酸盐为前驱体采用两步法制备了一种以CaO-MgO作为活性组分,以CoFe_2O_4作为磁核的磁性固体碱催化剂,并用于大豆油与甲醇的酯交换反应合成生物柴油。对制备的磁性固体碱催化剂进行了磁滞回线、X-射线衍射(XRD)、CO_2-TPD及透射电镜(TEM)表征。考察了不同核壳物质的量比、焙烧温度、反应温度、反应时间、醇油物质的量比以及催化剂用量等因素对大豆油转化为生物柴油产率的影响。结果表明,采用核壳物质的量比为1∶6、焙烧温度为700℃所制备的CaO-MgO@CoFe_2O_4催化剂,当醇油物质的量比为12、催化剂用量为大豆油质量的1.0%时,在65℃下反应时间3 h,生物柴油收率高达97.1%。该催化剂具有较好的重复利用性能,重复利用四次后生物柴油的收率仍可达90%。     

双核碱性离子液体催化棉籽油酯交换制备生物柴油

采用两步法制备了五种新型咪唑类碱性双核功能化离子液体化合物,并考察了对棉籽油酯交换制备生物柴油的催化性能。结果表明,咪唑类碱性双核功能化离子液体具有很好的催化活性,其催化活性与阳离子中碳链长度有关。其中,双-(3-甲基-1-咪唑)亚乙基双氢氧化物离子液体的催化活性最好。催化剂量、反应时间、反应温度及醇油比对生物柴油中脂肪酸甲酯含量及选择性影响的研究发现,在催化剂用量为0.4%(质量分数),醇油摩尔比为12,反应温度为55℃,反应时间为4 h时,脂肪酸甲酯的含量和选择性分别达98.5%和99.9%。催化剂7次循环后,产物中脂肪酸甲酯含量仍达到96.2%,单甘酯和双甘酯的含量很少,表明该催化剂重复使用良好。     

Cantilever Functionalization Using Peroxidase Extract of Low Cost for Glyphosate Detection

A highly efficient process for reducing the fatty acid (FA) content of high-acid rice bran oil (RBO) was developed by immobilized partial glycerides-selective lipase SMG1-F278N-catalyzed esterification/transesterification using methanol as a novel acyl acceptor. Molecular docking simulation indicated that methanol was much closer to the catalytic serine (Ser-171) compared with ethanol and glycerol, which might be one of the reasons for its high efficiency in the deacidification of high-acid RBO. Additionally, the reaction parameters were optimized to minimize the FA content of high-acid RBO. Under the optimal conditions (substrate molar ratio of methanol to FAs of 1.8:1, enzyme loading of 40 U/g, and at 30 °C), FA content decreased from 25.14 to 0.03% after 6 h of reaction. Immobilized SMG1-F278N exhibited excellent methanol tolerance and retained almost 100% of its initial activity after being used for ten batches. After purification by molecular distillation, the final product contained 97.86% triacylglycerol, 2.10% diacylglycerol, and 0.04% FA. The acid value of the final product was 0.09 mg KOH/g, which reached the grade one standard of edible oil. Overall, methanol was a superior acyl acceptor for the deacidification of high-acid RBO and the high reusability of immobilized SMG1-F278N indicates an economically attractive process.     

Transesterification of Soybean Oil Catalyzed by Calcium Hydroxide which Obtained from Hydrolysis Reaction of Calcium Carbide

Calcium carbide residue (CCR) was investigated in transesterification reaction of triglycerides to determine its viability as a solid catalyst for biodiesel synthesis. Literature survey showed that CCR has never been studied as a solid catalyst in the transesterification of triglyceride. The scope of the study includes the effects of CCR calcination temperature, calcination time, the alcohol/oil molar ratio, the catalyst amount (wt % of oil) and the reaction time. The relationship between chemical composition and catalytic activity of waste cement was also investigated. These CCR catalysts, thermally activated at 600 °C, can give rise to fatty acid methyl esters (FAME) purity higher than 99.5%, after 3 h of reaction, when oil/methanol molar ratio of 1/12 and 1 wt % of the catalyst were employed. Application of CCR as catalyst for biodiesel production in this study may not only provide a cost‐effective and environment friendly way of recycling CCR waste but also reduce hopefully the cost of biodiesel production.     

造纸白泥催化花生油与甲醇酯交换的特性研究

从催化剂用量、酯交换温度及时间、醇油物质的量比等影响因素出发,并借助热重、X射线荧光光谱、X射线衍射、氮气吸附与哈米特指示剂等催化剂表征手段,研究造纸白泥催化花生油与甲醇的酯交换特性.造纸白泥通过800 ℃煅烧-常温水合-600 ℃活化处理后,成分以CaO为主、比表面积为7.28 m²/g、碱性强度为9.8相似文献   

Optimization of process conditions for biodiesel production over CaO–Al<Subscript>2</Subscript>O<Subscript>3</Subscript>/ZrO<Subscript>2</Subscript> catalyst using response surface methodology

CaO–Al₂O₃/ZrO₂ mixed oxide catalyst was prepared using free-solvent method. The catalyst was characterized using X-ray diffraction, BET surface area, acidity index (obtained by titration method), and scanning electron microscopy (SEM). With calcium aluminate and calcium zirconate been successfully formed, the mix exhibited small crystal size, high acidity, and large surface area, pore size, and pore volume, making it a catalyst of choice for biodiesel production. The activity of catalyst was evaluated in the course of esterification of oleic acid as well as transesterification of waste cooking oil (WCO) into biodiesel. Based on a four-variable central composite design (CCD), response surface methodology (RSM) was used to optimize effective variables on oleic acid conversion. The optimum yield of 94.68% was obtained at the following set of optimum conditions: reaction temperature of 120 °C, methanol/oleic acid molar ratio of 15.64, catalyst concentration of 2.94 wt%, and reaction time of 4 h; the result was in excellent agreement with the predicted values. Furthermore, under the optimum conditions, the catalyst succeeded to convert 93.48% of WCO into biodiesel.     

Transesterification of palm oil using supercritical methanol with co-solvent HCFC-141b

The transesterification of palm oil in supercritical methanol has been investigated without using any catalyst. HCFC-141b was used as co-solvent to reduce the molar ratio of methanol to palm oil under the milder conditions. The reaction was carried out in a flow-type tubular reactor. The residence time was fixed at 40 min. When the molar ratio of methanol to palm oil was set to 20:1 at 325 °C and 35 MPa, the optimum molar ratio of methanol to co-solvent was found to be 20:1. Addition of HCFC-141b increased FAME production even at the lower molar ratio of methanol to palm oil. In addition, a similar FAME content was obtained under the milder conditions (5 MPa lower pressure) compared with conditions without co-solvent at higher pressure. The role of HCFC-141b in the transesterification reaction under supercritical conditions was investigated.     

Application of a Chitosan-Immobilized Talaromyces thermophilus Lipase to a Batch Biodiesel Production from Waste Frying Oils

Waste frying oil, which not only harms people’s health but also causes environmental pollution, can be a good alternative to partially substitute petroleum diesel through transesterification reaction. This oil contained 8.8 % of free fatty acids, which cause a problem in a base-catalyzed process. In this study, synthesis of biodiesel was efficiently catalyzed by the covalently immobilized Talaromyces thermophilus lipase and allowed bioconversion yield up to 92 % after 24 h of reaction time. The optimal molar ratio was four to six parts of methanol to one part of oil with a biocatalyst loaded of 25 wt.% of oil. Further, experiments revealed that T. thermophilus lipase, immobilized by a multipoint covalent liaison onto activated chitosan via a short spacer (glutaraldehyde), was sufficiently tolerant to methanol. In fact, using the stepwise addition of methanol, no significant difference was observed from the one-step whole addition at the start of reaction. The batch biodiesel synthesis was performed in a fixed bed reactor with a lipase loaded of 10 g. The bioconversion yield of 98 % was attained after a 5-h reaction time. The bioreactor was operated successfully for almost 150 h without any changes in the initial conversion yield. Most of the chemical and physical properties of the produced biodiesel meet the European and USA standard specifications of biodiesel fuels.     

Enzymatic Biodiesel Synthesis in Semi-Pilot Continuous Process in Near-Critical Carbon Dioxide

A semi-pilot continuous process (SPCP) for enzymatic biodiesel synthesis utilizing near-critical carbon dioxide (NcCO₂) as the reaction medium was developed with the aim of reducing the reaction time and alleviating the catalyst inhibition by methanol. Biodiesel synthesis was evaluated in both lab-scale and semi-pilot scale reactors (batch and continuous reactors). In a SPCP, the highest conversion (～99.9 %) in four and a half hours was observed when three-step substrate (methanol) addition (molar ratio [oil/methanol]?=?1:1.3) was used and the reaction mixture containing enzyme (Lipozyme TL IM, 20 wt.% of oil) was continuously mixed (agitation speed?=?300 rpm) at 30 °C and 100 bar in a CO₂ environment. The biodiesel produced from canola oil conformed to the fuel standard (EU) even without additional downstream processing, other than glycerol separation and drying.