Methanolysis of seed oils in flowing supercritical carbon dioxide

The direct methanolysis of triglycerides in flowing supercritical carbon dioxide by an immobilized lipase is described. The reaction system consists of two syringe pumps for substrate addition and another two syringe pumps for delivering CO₂ at 24.1 MPa. Corn oil is pumped into the carbon dioxide stream at a rate of 4 μL/min, and methanol is pumped at 5 μL/min to yield fatty acid methyl esters (FAME) at >98% conversion. Direct methanolysis of soy flakes gives FAME at similar yields. This combined extraction/reaction is performed at 17.2 MPa and 50°C. The fatty acid profiles obtained for these seed oils matches those obtained by classical chemical synthesis.     

Kinetics of hydroxide‐catalyzed methanolysis of crude sunflower oil for the production of fuel‐grade methyl esters

Methyl esters from crude sunflower oil were produced via methanolysis reaction using sodium hydroxide catalyst. Methanolysis was carried out at different agitation speeds (200–600 rpm), temperatures (25–60 °C), catalyst loadings (0.25–1.00% by weight of oil), and methanol:oil mole ratios (6:1–20:1). Mass‐transfer limitation was effectively minimized at agitation speeds of 400–600 rpm with no apparent lag period. Lowering the temperature resulted in a fall in the rate of reaction prolonging the reaction time necessary to achieve maximum production of methyl ester. Using 0.50% hydroxide catalyst was found to be adequate, resulting in 97–98% conversion without compromising recovery due to soap formation. Increasing the methanol:oil mole ratio beyond the usual amount of 6:1 tended to speed up the initial rate of methanolysis and was found to lower the bonded glycerol content, especially the amount of diglyceride in the sample. Kinetic rate constants were derived from experimental results using second‐order rate expressions, and values of activation energy for glyceride methanolysis have been established. Copyright © 2007 Society of Chemical Industry     

Alcoholysis of triacylglycerols by heterogeneous catalysis

Synthesis of fatty acid esters by alcoholysis, especially methanolysis of triacylglycerols was investigated using metal salts of amino acids as catalysts. The methanol to oil molar ratio was 6:1. It could be shown that salts containing a quaternary amino or a highly basic group as e.g. a guanidino group have catalytic activity in alcoholysis. Some of these salts are insoluble in monovalent alcohols, glycerol, and fatty acids esters and are therefore suitable catalysts for heterogeneously catalysed alcoholysis. Zinc salts of arginine, carnitine or histidine are among others suited for industrial use. These catalysts are also suitable for heterogeneously catalysed interesterification.     

Biodiesel production by direct methanolysis of oleaginous microbial biomass

Biodiesel is a renewable fuel conventionally prepared by transesterification of pre‐extracted vegetable oils and animal fats of all resources with methanol, catalyzed by strong acids or bases. This paper reports on a novel biodiesel production method that features acid‐promoted direct methanolysis of cellular biomass of oleaginous yeasts and filamentous fungi. The process was optimized for tuning operation parameters, such as methanol dosage, catalyst concentration, reaction temperature and time. Up to 98% yield was reached with reaction conditions of 70 °C, under ambient pressure for 20 h and a dried biomass to methanol ratio 1:20 (w/v) catalyzed by either 0.2 mol L^?1 H₂SO₄ or 0.4 mol L^?1 HCl. Cetane numbers for these products were estimated to range from 56 to 59. This integrated method is thus effective and technically attractive, as dried microbial biomass as feedstocks omits otherwise tedious and time‐consuming oil extraction processes. Copyright © 2007 Society of Chemical Industry     

Biodiesel production by the transesterification of cottonseed oil by solid acid catalysts

Methyl esters (biodiesel) were produced by the transesterification of cottonseed oil with methanol in the presence of solid acids as heterogeneous catalysts. The solid acids were prepared by mounting H₂SO₄ on TiO₂ · nH₂O and Zr(OH)₄, respectively, followed by calcining at 823K. TiO₂-SO₄ ²⁻ and ZrO₂-SO₄ ²⁻ showed high activity for the transesterification. The yield of methyl esters was over 90% under the conditions of 230°C, methanol/oil mole ratio of 12:1, reaction time 8 h and catalyst amount (catalyst/oil) of 2% (w). The solid acid catalysts showed more better adaptability than solid base catalysts when the oil has high acidity. IR spectral analysis of absorbed pyridine on the samples showed that there were Lewis and Br?nsted acid sites on the catalysts. Translated from The Chinese Journal of Process Engineering, 2006, 6(4): 571–575 [译自: 过程工程学报]     

Identification, FT-IR, NMR (H and C) and GC/MS studies of fatty acid methyl esters in biodiesel from rocket seed oil

Biodiesel was synthesized from rocket seed oil by base-catalyzed transesterification with methanol. The synthesis of biodiesel was confirmed by FT-IR and NMR (¹H and ¹³C) spectroscopy. Various fuel properties of the synthesized biodiesel were determined using ASTM methods and discussed accordingly. A total of eleven fatty acid methyl esters (FAMEs) were identified in rocket seed oil biodiesel (RSOB) by the retention time and the fragmentation pattern data of GC/MS analysis. The identified FAMEs were, methyl 9-hexadecenoate (C16:1), 14-methyl pentadecanoate (C16:0), methyl 9,12-octadecadienoate (C18:2), methyl 9-octadecenoate (C18:1), methyl octadecanoate (C18:0), methyl 11-eicosenoate (C20:1), methyl eicosanoate (C20:0), methyl 13-docosenoate (C22:1), methyl docosanoate (C22:0), methyl 15-tetracosenoate (24:1) and methyl tetracosanoate (C24:0). The percentage conversion of triglycerides to corresponding methyl esters determined by ¹H NMR was 88.49%.     

酯交换法制备生物柴油及其在我国的实践

生物柴油是一种对环境友好的可再生燃料.综述并比较了生物柴油的各种化学制备方法,介绍了该产业的生产应用情况,指出了生物柴油的优势,分析了生物柴油在生产及使用过程中存在的一些问题并对生物柴油的未来研究与发展作了展望.     

膨润土催化脂肪酸甲酯合成二聚酸甲酯的工艺优化

利用响应面方法优化膨润土催化脂肪酸甲酯合成二聚酸甲酯的工艺参数,得到最优参数为:催化剂加入量10%,催化助剂LiCl 0.8%,反应温度220℃,反应时间6 h。在最优条件下,二聚体收率为64.8%,产物的理化特性分析显示各项性能指标优良。     

葵花籽油制备生物柴油的研究

介绍了在碱催化剂作用下以葵花籽油与甲醇反应生成生物柴油的工艺条件,考察了醇油摩尔比、催化剂用量、反应温度、反应时间等条件对反应的影响,采用正交实验的方法得出最佳的反应条件:醇油摩尔比6:1、催化剂用量0．9％、反应温度60℃、反应时间50 min。对所得到生物柴油的主要性能与柴油进行对比,其指标均符合0#矿物柴油标准。     

The pseudo-single-phase,base-catalyzed transmethylation of soybean oil

The base-catalyzed transmethylation of soybean oil has been studied under conditions whereby the reaction starts as a single phase, but later becomes two phases as glycerol separates. Methanol/oil molar ratios of 6∶1 were used at 23°C. The catalysts were sodium hydroxide (0.5, 1.0, and 2.0 wt%), potassium hydroxide (1.0 and 1.4 wt%), and sodium methoxide (0.5, 1.0, and 1.35 wt%), all concentrations being with respect to the oil. Oxolane (tetrahydrofuran) was used to form a single reaction phase. The reactions deviated from homogeneous kinetics as glycerol separated, taking with it most of the catalyst. When 1.0 wt% sodium hydroxide was used, the methyl ester content reached 97.5 wt% after 4 h, compared with 85–90 wt% in the two-phase reaction. Sodium hydroxide (1.0 wt%), sodium methoxide (1.35 wt%), and potassium hydroxide (1.4 wt%) gave similar results, presumably because the same number of moles was used. The ASTM biodiesel specification for chemically bound glycerol was achieved after only 3 min when 2.0 wt% sodium hydroxide was used. However, the standard was not achieved after 4 h when 1.0 wt% sodium hydroxide was used, the MG content being 1.1–1.6 wt%. The use of 2.0 wt% catalyst is commercially impractical.     

Determining the acid number of biodiesel

Commerical biodiesel is composed of FAME. It may also contain small amounts of FA, which are quantified by an acid number, expressed as milligrams of potassium hydroxide required to neutralize 1 g of sample. In 2006, the ASTM D 6751 biodiesel acid-number limit was harmonized with the European biodiesel value of 0.50. ASTM D 664 is the standard reference method for measuring the acid number of both ASTM biodiesel and petroleum-derived diesel. This potentiometric method cites acceptable repeatability and mediocre reproducibility, but no information on accuracy. ASTM D 974 is a non-aqueous colorimetric titration that uses potassium hydroxide in isopropanol as the titrant and p-naphtholbenzein as indicator. It was designed for petroleum products and is suitable for colored samples. It has been tested on nine palmitic acid/soybean oil standards in the acid-number range of 0.198 to 1.17. All accuracies were within 3.3%. The repeatability was approximately 6% at an acid number of 0.5. The reproducibility appears to be only slightly greater than the repeatability at an acid number of 0.5. It is concluded that ASTM D 974 is a good method for evaluating the acid-number compliance of biodiesel samples.     

固体酸催化棉籽油酯交换制备生物柴油

生物柴油(脂肪酸甲酯)可以由棉籽油与甲醇在酸催化剂的作用下通过酯交换反应制得. 通过硫酸改性氧化钛、氧化锆,并经过高温煅烧得到了相应的固体强酸催化剂TiO2-SO42-, ZrO2-SO42-,并对催化剂活性进行了评价. 实验结果表明,TiO2-SO42-和ZrO2-SO42-与改性前的氧化物相比具有较高的酯交换反应活性. 在230℃、醇油摩尔比12:1及催化剂用量为棉籽油2%(w)的条件下,反应8 h后甲酯的收率达到90%以上. 与固体碱催化剂相比,固体酸催化剂对原料的酸度有更强的适应性. 红外吡啶吸附光谱表明,TiO2-SO42-与ZrO2-SO42-具有较强的L酸和B酸中心.     

脂肪酶催化非食用植物油制备生物柴油的过程优化

以麻疯树油、亚麻油、乌柏油为原料油,采用固定化脂肪酶Lipozyme TL IM,在3.0 g油、1 mL正己烷、醇油摩尔比为3.5∶1、固定化酶质量为油质量20%的条件下进行生物柴油的制备,通过脂肪酸甲酯产率和组成分析,以考察生物柴油制备的影响因素,进行反应时间优化.结果表明,酶的催化作用对脂肪酸组分不存在选择性,且...     

Synthesis of biodiesel from sunflower oil with silica‐supported NaOH catalysts

BACKGROUND: A series of NaOH catalysts supported on commercial silica have been prepared by conventional incipient wetness impregnation and their activity tested in the reaction of transesterification of refined sunflower oil with methanol at 323 K and atmospheric pressure. The effects of the molar methanol/oil ratio, catalyst concentration, NaOH loading and calcination of the supported catalysts have been investigated. RESULTS: It has been found that the transesterification rate largely depends on the catalyst/methanol ratio and that calcination of the NaOH catalysts supported on silica, even at moderate temperatures, had a very negative effect on their activity. Selectivity, on the other hand, is more affected by the methanol/oil ratio. Selectivity for methyl esters (biodiesel) improved with the methanol/oil ratio due to an increased transesterification rate of diglycerides, whereas the selectivity for monoglycerides was not affected. CONCLUSION: The NaOH/silica catalysts suffered from a significant lack of chemical stability under reaction conditions as evidenced by measurements of sodium extracted during the reaction progress; therefore, their performance was affected by the presence of Na dissolved in the methanol phase. Copyright © 2008 Society of Chemical Industry     

国内外生物柴油研究生产现状及发展趋势

可替代柴油的生物柴油在国内外研究及生产的现状和发展趋势,指出了生物柴油的优势及生物柴油制备、应用中存在的问题,分析了发展生物柴油产业对我国石油安全、国民经济建设、农业产业结构调整和环境保护的作用,并展望了该产业的发展前景。     

Biodiesel Production from Rubber Seed Oil by Transesterification Using a Co‐solvent of Fatty Acid Methyl Esters

Rubber seed oil (RSO) is a high‐potential feedstock for the production of biodiesel fuel (BDF) in Asia. Transesterification using fatty acid methyl esters (FAMEs) as co‐solvents was developed for BDF production from RSO with high content of free fatty acids (FFAs). The homogeneous system (FAMEs/triglyceride/methanol) was attained when the FAME content was more than 30 wt %. After esterification of RSO, the crude RSO obtained was transesterified with FAMEs as a co‐solvent. The quality of BDF with high FAME content satisfied the criteria of the EN 14214/JIS K2390 standards. These results suggest that FAMEs converted from FFAs can be applied as a co‐solvent and, thus, reused for BDF production.     

Comparison of Fatty Acid Methyl and Ethyl Esters as Biodiesel Base Stock: a Review on Processing and Production Requirements

Fatty acid methyl esters (FAME) were the first fatty acid esters to be introduced for use as biodiesel. However, there is a growing interest in the use of fatty acid ethyl esters (FAEE) in biodiesel. Both FAME and FAEE have their own unique advantages and disadvantages. These differences are ultimately attributable to the structural differences imparted by the alcohols used in their production. Sources of reactants as well as their safety issues, are a focus of this review. Also reviewed are the comparative characteristics and properties of both biodiesel types in terms of physicochemical features and performance. Processing requirements, reaction times and molar ratios of alcohol to oil, together with problems and drawbacks, are discussed. Recent developments on improving the yield of biodiesel, include mixing methanol and ethanol in the same reaction with ethanol acting as a co-solvent, and enzymatic methanolysis and ethanolysis are also highlighted.     

废旧光盘在离子液体中的甲醇醇解反应

以离子液体［Bmim］［Cl］为反应介质和催化剂,对废旧光盘的甲醇醇解反应进行了研究。考察了反应温度、反应时间、催化剂用量、甲醇用量对醇解反应结果的影响,得到的较佳醇解反应条件为反应温度110℃,反应时间1.5 h,n(甲醇)∶n(光盘)=8∶1,m(［Bmim］［Cl］)∶m(光盘)=1∶1,在上述条件下,光盘醇解率≥98%,双酚A收率≥93%。对离子液体的回用性能进行了考察,结果表明,离子液体回用8次后光盘的醇解率和BPA的收率无明显变化。采用FT-IR技术对醇解产物进行了表征。     

Transesterification of brazilian vegetable oils with methanol over ion-exchange resins

The transesterification of several Brazilian vegetable oils with methanol was carried out at 60°C in the presence of several ion-exchange resins having different structures. The vegetable oils used were from Babassu coconut, corn, palm, palm kernel, and soybean. The effect of the methanol/oil mole ratio and the influences of the structure of the ion-exchange resin and the type of vegetable oil used on the catalytic activity of the ionexchange resins were investigated. The resins used were Amberlyst 15, Amberlyst 31, Amberlyst 35, and Amberlyst 36. Amberlyst 15 produced the best results for the transesterification of vegetable oils. The methyl ester yield is higher for palm kernel oil and Babassu coconut oil than for soybean oil, probably owing to their higher content of shorter-chain FA. Therefore, it was shown that the catalytic activity of the resin depends on the FA composition of the vegetable oil employed.     

棉籽油酯交换制备生物柴油固体碱催化过程研究

生物柴油(脂肪酸甲酯)可以由棉籽油与甲醇在碱催化剂的作用下通过酯交换反应制得.本实验通过高温煅烧氢氧化镁、碳酸钙及镁-铝水滑石得到了相应的固体碱催化剂MgO、CaO及MgO-Al2O3,并对催化剂活性进行评价.实验结果表明,CaO及MgO-Al2O3具有较高的酯交换反应活性:在230℃,醇油摩尔比12:1及催化剂用量为棉籽油2%(wt)的条件下,反应3 h后,甲酯的收率达到90%以上.CO2-TPD实验结果表明,CaO 及MgO-Al2O3具有较强和较多的碱性位,而催化剂的活性与碱强度及碱性位数量直接相关.