固定化脂肪酶催化高酸废油脂酯交换生产生物柴油

 探讨了固定化脂肪酶Novozym 435催化高酸废油脂与乙酸甲酯酯交换生产生物柴油. Novozym 435能催化高酸废油脂与乙酸甲酯的酯交换反应,反应24 h后甲酯产率为77.5%,但该值大大低于以精制玉米油为原料时的甲酯产率(86.2%). 系统研究了反应体系中的水、游离脂肪酸和乙酸对反应的影响. 当反应体系中的水含量低于0.05%时,水对酶反应速率和甲酯产率影响甚小,而水含量高于0.05%时,酶反应速率和甲酯产率随着水含量的增加而降低. 游离脂肪酸对反应有较大影响,甲酯产率随着游离脂肪酸含量的增加而急剧下降. 乙酸甲酯与游离脂肪酸反应产生的副产物乙酸是导致甲酯产率显著下降的原因. 在反应体系中添加适量(油重的10%)的有机碱三羟甲基氨基甲烷或三乙胺可有效提高酶促高酸废油脂的酯交换反应速率和甲酯产率,使反应12 h后的甲酯产率分别达到85.9%和80.8%; 碱的加入还提高了酶的操作稳定性,添加有机碱三羟甲基氨基甲烷或三乙胺可使反应10批次后Novozym 435的相对酶活力分别由对照值86%提高到97%和93%.     

柴油溶剂中脂肪酶催化高酸值废油脂酯化制备生物柴油

采用0＃柴油作为反应溶剂,利用固定化脂肪酶催化高酸值废油脂与甲醇酯化反应制备生物柴油。来源于Candida antarctica的固定化脂肪酶Novozym435在0＃柴油溶剂中具有极高的催化活性。以酸价高达157×10-3的废油脂为原料,废油脂质量比10%的Novozym435,甲醇与废油脂初始摩尔比2∶1,0＃柴油与废油脂质量比5∶1,摇床摇速170r/min,50℃下反应2h甲酯化率可达95.10%。0＃柴油作为反应溶剂有效地溶解了高酸值废油脂和甲醇,降低了反应体系的黏度和消除了甲醇对Novozym435的负面影响,提高了Novozym435的稳定性。同时,0＃柴油溶剂对未脱胶废油脂中残留的对脂肪酶有害的磷脂等胶类物质具有一定的稀释作用。该工艺省却了溶剂蒸馏的繁琐工序,直接得到脂肪酸甲酯和石化柴油的混合燃料。     

无溶剂系统中固定化脂肪酶催化废油脂转酯生产生物柴油

 探讨了无溶剂系统中固定化脂肪酶Novozym 435催化餐饮业废油脂转酯生产生物柴油. 反应副产物甘油可吸附在固定化酶载体表面,采用丙酮洗涤除去甘油可提高酶的稳定性. 适宜的醇/油摩尔比、酶用量、反应温度和摇床转速分别为1, 6.6 U/g, 35～40 ℃和150 r/min,不宜加水到反应体系中. 采用分步加入甲醇的方式可减轻甲醇对酶的毒害作用. 分别在反应进行到6和14 h时用丙酮除去酶表面的甘油,然后按醇/油摩尔比为1的比例加入甲醇继续反应,反应30 h后产物中的脂肪酸甲酯含量为88.6%. 连续反应300 h后,酶活性基本没有下降.     

固体碱KF/Sm2O3催化菜籽油制备生物柴油

以菜籽油为原料,研究了负载型固体碱催化剂KF/Sm2O3在酯交换制备生物柴油过程中的催化活性.用气相色谱法对酯交换产物进行分析,并用CO2-TPD,XRD,Ramaa等技术对催化剂进行了表征.当催化剂焙烧温度为873 K,KF负载量为15%,甲醇跟菜籽油的计量比为12:1,催化剂用量为菜籽油质量的3%,反应温度为338 K,反应时间为1 h时,生物柴油产率达到95.1%.     

废茶油的精制及其合成生物柴油的研究

本文以废茶油为原料,经过脱胶脱酸等预处理后与甲醇进行酯交换反应制取生物柴油.探讨了反应时间、反应温度、醇-油摩尔比和催化剂用量等因素对废茶油-甲醇酯交换反应的影响,并且采用正交实验优化合成条件,确定了反应的最佳操作条件以及影响反应的关键因素.研究结果表明,酯交换反应进行的最佳反应条件为:醇油摩尔比为25:1、催化剂用量为油重的1.0%、反应时间为30min、反应温度为60℃,茶油酸甲酯产率77.34%.     

游离脂肪酶NS81006催化油脂醇解制备生物柴油的酶促反应动力学

探究了游离脂肪酶NS81006催化油脂甲(乙)醇解制备生物柴油的反应历程,并对该体系进行了酶促反应动力学研究.结果表明,催化过程中油脂同时存在酯交换及先水解再酯化两种反应历程.在以甲醇或乙醇作为酰基受体的反应过程中,酯交换反应速率明显大于水解反应速率.进一步研究表明,油脂甲醇解反应速率常数大于乙醇解,揭示了以甲醇或乙醇为不同酰基受体时反应速率存在差异的主要原因在于乙醇解反应的酯交换过程较慢.     

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。     

基于纤维素的固体酸催化剂的制备及其催化高酸值废油脂生产生物柴油

以廉价的纤维素为原料,经不完全炭化和磺化制得含高密度(1.69 mmol/g) SO3H基团的固体酸催化剂Cellulose-SO3H.结果表明,该催化剂适宜的制备条件为:在400℃炭化15h,再在150℃磺化15h.所得催化剂在油酸与甲醇的酯化反应中表现出明显高于其它几种典型固体酸催化剂(铌酸,Amberlyst- ...     

廉材担大任——氧化钙催化生物柴油制备反应

以化学反应的方向、有机物官能团等中学化学知识为基础,介绍常见化合物CaO用作酯交换反应的催化剂制备生物柴油的基础知识。为弥补现行高中化学教材的不足,特意着重介绍催化原理和应用研究的一些重要动态,以帮助高中生拓展视野,发展现代化学思维。     

Ca/Al固体碱催化菜籽油制备生物柴油

采用共沉淀法制备了Ca/Al复合氧化物固体碱催化剂,考察了沉淀剂种类、Ca/Al摩尔比、沉淀温度、溶液pH值、老化时间和焙烧温度等制备条件对其催化剂活性的影响。采用正交实验方法得到制备Ca/Al复合固体碱催化剂前躯体的最佳制备条件为,沉淀剂NaOH,Ca/Al摩尔比为3,沉淀温度为60 ℃,沉淀过程中pH值保持在10,在90 ℃老化18 h。在该最优条件下制备的催化剂前驱体主要以Ca₄Al₂O₆(NO₃)₂·10H₂O晶相存在,在N₂气保护下300 ℃焙烧2 h后,催化剂形成高分散钙铝复合氧化物,且碱性强度达到26.5以上。在催化菜籽油和甲醇的酯交换反应中,菜籽油的转化率达到95%,脂肪酸甲酯的质量分数为95.9%。     

Biodiesel Production from Waste Cooking Oil over Mesoporous SO42-/Zr-SBA-15

Biodiesel production from waste cooking oils over SO₄^2-/Zr-SBA-15 catalyst was successfully carried out and investigated. SO₄^2-/Zr-SBA-15 catalyst was prepared by one-step process using anhydrous zirconium nitrate as zirconium resource, and endowed with the strong Lewis acid sites formed by supporting the zirconium species onto the SBA-15 surface. The asprepared SO₄^2-/Zr-SBA-15 showed excellent triglyceride conversion efficiency of 92.3% and fatty acid methyl esters (FAME) yield of 91.7% for the transesteriffication of waste cooking oil with methanol under the optimized reaction conditions: the methanol/oil molar ratio of 30, the reaction temperature of 160 oC, the reaction time of 12 h and 10wt% of catalyst. It was noticed that the as-prepared SO₄^2-/Zr-SBA-15 materials with the higher area surface of mesoporous framework and the surface acidity displayed excellent stability and reusability, maintaining high FAME yield of (74±1)% after seven runs of reaction.     

Production and Characterization of Biodiesel from Tung Oil

The feasibility of biodiesel production from tung oil was investigated. The esterification reaction of the free fatty acids of tung oil was performed using Amberlyst-15. Optimal molar ratio of methanol to oil was determined to be 7.5:1, and Amberlyst-15 was 20.8wt% of oil by response surface methodology. Under these reaction conditions, the acid value of tung oil was reduced to 0.72mg KOH/g. In the range of the molar equivalents of methanol to oil under 5, the esterification was strongly affected by the amount of methanol but not the catalyst. When the molar ratio of methanol to oil was 4.1:1 and Amberlyst-15 was 29.8wt% of the oil, the acid value decreased to 0.85mg KOH/g. After the transesterification reaction of pretreated tung oil, the purity of tung biodiesel was 90.2wt%. The high viscosity of crude tung oil decreased to 9.8mm²/s at 40 °C. Because of the presence of eleostearic acid, which is a main component of tung oil, the oxidation stability as determined by the Rancimat method was very low, 0.5h, but the cold filter plugging point, −11 °C, was good. The distillation process did not improve the fatty acid methyl ester content and the viscosity.     

An Organic Soluble Lipase for Water-Free Synthesis of Biodiesel

Lipase AK was modified with short alkyl chains to form a highly organic soluble enzyme and was used to catalyze the synthesis of biodiesel from soybean oil in organic media. The effects of several key factors including water content, temperature, and solvent were examined for the solubilized enzyme in comparison with several other commercially available lipases. Whereas native lipases showed no activity in the absence of water, the organic soluble lipase demonstrated reaction rates of up to 33 g-product/g-enzyme h. The biocatalyst remains soluble in the biodiesel product, and therefore, there is no need to be removed because it is expected to be burned along with the diesel in combustion engines. This provides a promising one-pot mix-and-use strategy for biodiesel production.     

Lipase-Catalyzed Transesterification of Rapeseed Oil for Biodiesel Production with tert-Butanol

Biodiesel is a fatty acid alkyl ester that can be derived from any vegetable oil or animal fat via the process of transesterification. It is a renewable, biodegradable, and nontoxic fuel. In this paper, we have evaluated the efficacy of a transesterification process for rapeseed oil with methanol in the presence of an enzyme and tert-butanol, which is added to ameliorate the negative effects associated with excess methanol. The application of Novozym 435 was determined to catalyze the transesterification process, and a conversion of 76.1% was achieved under selected conditions (reaction temperature 40 °C, methanol/oil molar ratio 3:1, 5% (w/w) Novozym 435 based on the oil weight, water content 1% (w/w), and reaction time of 24h). It has also been determined that rapeseed oil can be converted to fatty acid methyl ester using this system, and the results of this study contribute to the body of basic data relevant to the development of continuous enzymatic processes.     

Biodiesel preparation from transesterification of glycerol trioleate catalyzed by basic ionic liquids

In the present study,the transesterification of glycerol trioleate was carried out over a basic ionic liquid,1-butyl-3- methylimidazolium hydroxide([Bmim]OH) and an 87.2%yield of methyl ester was achieved.The product was isolated through simple decantation from the biphasic system due to the immiscibility of[BmimJOH with ester.[Bmim]OH can be easily recovered and reused six times without dramatic decrease in ester yield.     

Biodiesel Production by Single and Mixed Immobilized Lipases Using Waste Cooking Oil

Biodiesel is one of the important biofuels as an alternative to petroleum-based diesel fuels. In the current study, enzymatic transesterification reaction was carried out for the production of biodiesel from waste cooking oil (WCO) and experimental conditions were optimized, in order to reach maximum biodiesel yield. Bacillus stearothermophilus and Staphylococcus aureus lipase enzymes were individually immobilized on CaCO₃ to be used as environmentally friendly catalysts for biodiesel production. The immobilized lipases exhibited better stability than free ones and were almost fully active after 60 days of storage at 4 °C. A significant biodiesel yield of 97.66 ± 0.57% was achieved without any pre-treatment and at 1:6 oil/methanol molar ratio, 1% of the enzyme mixture (a 1:1 ratio mixture of both lipase), 1% water content, after 24 h at 55 °C reaction temperature. The biocatalysts retained 93% of their initial activities after six cycles. The fuel and chemical properties such as the cloud point, viscosity at 40 °C and density at 15 °C of the produced biodiesel complied with international specifications (EN 14214) and, therefore, were comparable to those of other diesels/biodiesels. Interestingly, the resulting biodiesel revealed a linolenic methyl ester content of 0.55 ± 0.02% and an ester content of 97.7 ± 0.21% which is in good agreement with EN14214 requirements. Overall, using mixed CaCO₃-immobilized lipases to obtain an environmentally friendly biodiesel from WCO is a promising and effective alternative for biodiesel production catalysis.     

Catalytic Transesterification of Coconut Oil in Biodiesel Production: A Review

Catalysis Surveys from Asia - Biodiesel is one of the renewable energy (RE) sources that has received much interest due to its promising properties. Recently, the use of coconut oil as biodiesel...     

Heterogeneous Base Catalysts for Transesterification in Biodiesel Synthesis

The heterogeneous base-catalyzed transesterification for biodiesel synthesis has been studied intensively over the last decade. This review classifies the solid base catalysts for transesterification into the following six categories based on Hattori’s classification: single metal oxides, mixed metal oxides, zeolites, supported alkali/alkaline earth metals, clay minerals (hydrotalcites), and non-oxides (organic solid bases). The catalysts in each category have acceptable catalytic activities overall, and follow specific catalyst design rules, although not completely systematically, thereby drawing the best activity from them. In parallel, each catalyst is not versatile and has some limitations specifically related to its catalytic structure and properties. This review focuses on the heterogeneous base-catalyzed transesterification in terms of catalyst development, based on the published research, especially over the last decade.     

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.     

Effect of Solvent on the Extraction of Microalgae Lipid for Biodiesel Production

The effect of solvent on the microalgae lipid extraction was studied. The efficiency of lipid extraction from microalgae was found to differ according to the solvent used. The existence of formic acid contributed to the extraction of lipid to a great extent. With 8 mg/L formic acid existing in the system, the lipid yield and free fatty methyl ester(FAME) yield increased from 39% to 42% and from 81% to 90% respectively compared to those of the control. The highest lipid yield of 42% was achieved from Chlorella protothecoidesis with an FAME yield of 89% when a mixed solvent of 14 mL/g dichloromethane, 2 mL/g methanol and 4 mL/g formic acid was used.