Simple, high-efficiency synthesis of fatty acid methyl esters from soapstock

We report a simple method that efficiently esterifies the fatty acids in soapstock, an inexpensive, lipid-rich by-product of edible oil production. The process involves (i) alkaline hydrolysis of all lipid-linked fatty acid ester bonds and (ii) acid-catalyzed esterification of the resulting fatty acid sodium salts. Step (i) completely saponified all glycerides and phosphoglycerides in the soapstock. Following water removal, the resulting free fatty acid sodium salts were rapidly and quantitatively converted to fatty acid methyl esters (FAME) by incubation with methanol and sulfuric acid at 35°C and ambient pressure. Minimum molar reactant ratios for full esterification were fatty acids/methanol/sulfuric acid of 1∶30∶5. The esterification reaction was substantially complete within 10 min and was not inhibited by residual water contents up to ca. 10% in the saponified soapstock. The product FAME contained >99% fatty acid esters, 0% triglycerides, <0.05% diglycerides, <0.1% monoglycerides, and <0.8% free fatty acids. Free fatty acid levels were further reduced by washing with dilute sodium hydroxide. Free and total glycerol were <0.01 and <0.015%, respectively. The water content was <0.04%. These values meet the current specifications for biodiesel, a renewable substitute for petroleum-derived diesel fuel. The identities and proportions of fatty acid esters in the FAME reflected the fatty acid content of soybean lipids. Solids formed during the reaction contained 69.1% ash and 0.8% protein. Their sodium content indicated that sodium sulfate was the prime inorganic component. Carbohydrate was the predominant organic constituent of the solid.     

Preparation of alkenyl succinic anhydrides from vegetable oil FAME

Sunflower oil and oleic motif-enriched sunflower oil methyl esters were used to prepare alkenyl succinic anhydrides. A classic batch reactor was selected to carry out the synthesis. The range in which the temperature, reaction time, and molar ratio between the number of moles of maleic anhydride and the equivalent number of double bonds present in the unsaturated vegetable oil methyl esters (the most influential factors in the process) varied was determined in a preliminary study. A secondorder Doehlert uniform network design was used to investigate the influence of the temperature and molar ratio for all the methyl esters on the yield of alkenyl succinic anhydride from methyl oleate, the conversion of methyl oleate, the formation of side reaction products, the Gardner color of the product, and viscosity. The optimal reaction conditions for obtaining the maximal yield (around 95%) of alkenyl succinic anhydride from methyl oleate were 235°C, a molar ratio of 1.5, and a reaction lasting 8 h. However, the products synthesized under these conditions showed high viscosity (215 cP), a very dark color (18+ Gardner color), and a high content of undesirable side products (4%), which hindered their direct industrial use. The increase in the product viscosity was probably due to the formation of side reaction products. A molar ratio of less than 1.5 led to a less viscous product, although with a lower alkenyl succinic anhydride content.     

双液相萃取棉籽油制备脂肪酸甲酯

以双液相萃取技术处理棉籽,在得到脱毒棉粕的同时得到含有高质量毛油的非极性相。以非极性相作为与甲醇进行酯交换反应的原料,得到脂肪酸甲酯和甘油。考察了非极性相溶剂石油醚与棉籽油的比例对酯交换转化率和洗涤粗产品用水量的影响,确定了石油醚与棉籽油的最佳质量比为3,在此条件下,洗涤用水量可降低一半。考察了醇油比、催化剂用量、反应温度、反应时间等参数对转化率的影响。应用正交实验的方法找出酯交换反应的适宜条件为：醇油比6：1,催化剂用量1.1％,反应温度60℃,反应时间120min。在此反应条件下,产物中脂肪酸甲酯的含量可达97.4％。     

<Emphasis Type="Italic">In situ</Emphasis> alkaline transesterification: An effective method for the production of fatty acid esters from vegetable oils

The production of simple alkyl FA esters by direct alkali-catalyzed in situ transesterification of the acylglycerols (AG) in soybeans was examined. Initial experiments demonstrated that the lipid in commercially produced soy flakes was readily transesterified during agitation at 60°C in sealed containers of alcoholic NaOH. Methyl, ethyl, and isopropyl alcohols readily participated in the reaction, suggesting that the phenomenon is a general one. Statistical experimental design methods and response surface regression analysis were used to optimize reaction conditions, using methanol as alcohol. At 60°C, the highest yields of methyl ester with minimal contamination by FFA and AG were predicted at a molar ratio of methanol/AG/NaOH of 226∶1∶1.6 with an approximately 8-h incubation. An increase in the amount of methanol, coupled with a reduced alkali concentration, also gave high ester yields with low FFA and AG contamination. The reaction also proceeded well at 23°C (room temperature), giving higher predicted ester yields than at 60°C. At room temperature, maximal esterification was predicted at a molar ratio of 543∶1∶2.0 for methanol/AG/NaOH, again in 8 h. Of the lipid in soy flakes, 95% was removed under such conditions. The amount of FAME recovered after in situ transesterification corresponded to 84% of this solubilized lipid. Given the 95% removal of lipid from the soy flakes and an 84% efficiency of conversion of this solubilized lipid to FAME, one calculates an overall transesterification efficiency of 80%. The FAME fraction contained only 0.72% (mass basis) FFA and no AG. Of the glycerol released by transesterification, 93% was located in the alcoholic ester phase and 75 was on the post-transesterification flakes.     

由菜籽油制备生物柴油的HPLC定量分析

采用反相液相色谱分离和紫外检测法定量分析了菜籽油制备生物柴油的主要组分分布及含量。结果表明,各脂肪酸甲酯、甘油单酯、甘油二酯及甘油三酯组分均能达到基线分离,且线性相关性良好,相关系数均在0.999 3以上,加标回收率在99.5%~103.7%之间,RSD在0.45%~2.38%(n)之间,该方法准确可靠。定量分析了菜籽油完全酯交换产品中油酸甲酯、亚油酸甲酯、亚麻酸甲酯组分含量分别为58.45%,20.02%,16.50%,三者之和为94.98%。菜籽油中三油酸甘油酯组分含量为38.76%。     

聚乙二醇改性植物油的催化剂研究进展

综述了植物油改性合成聚乙二醇脂肪酸酯的催化剂研究进展。提出采用固体碱为催化剂进行脂肪酸酯类化合物与聚乙二醇酯交换反应来制备聚乙二醇脂肪酸酯基的方法。指出固体碱催化剂在此酯交换反应中的优良性能和应用前景。     

茶油精炼副产物皂脚制备生物柴油的研究

以茶油精炼副产物皂脚和甲醇为原料,NaOH为催化剂,经酯交换合成生物柴油,研究了工艺条件对皂脚合成生物柴油收率的影响。结果表明,适宜的工艺条件为:醇油摩尔比为5∶1,反应时间为30 min,反应温度为30℃,催化剂NaOH用量为油重的0.7%,反应收率为98.0%。     

由氯乙酸副产盐酸精制高纯盐酸

开发研究了氯乙酸副产盐酸的精制工艺及盐酸中有机杂质的紫外分光光度分析方法。副产盐酸经酸洗、吸收、蒸馏得高纯盐酸。中试结果表明 ,工艺合理 ,精制盐酸达到GB 32 0 - 93规定的工业用合成盐酸标准     

Low-molecular weight organic composition of acid water from coconut oil soapstock

Soapstock from alkaline refining of coconut oil was acidified, and the resulting acid water after neutralization was subjected to gas chromatography, electron-ionization and chemical-ionization mass spectroscopy, and high-performance liquid chromatography. The chief low-molecular weight organic components were C₄−C₁₈ fatty acids, hydroxylated acids, and sugar alcohols. The prevalence of acids and total absence of phosphate compounds make coconut acid water different in composition from the acid waters from other soapstocks.     

Low-molecular weight organic compositions of acid waters from vegetable oil soapstocks

Alkaline extracts (soapstocks) from canola, corn, cottonseed, peanut, soybean, and sunflower oil refining were acidified, and identities and concentrations of the low-molecular weight organic components of the resulting acid waters were determined by gas chromatography, followed by mass spectroscopy, and by high-performance liquid chromatography. The main components of each acid water sample, in order of decreasing concentration and after omitting the fermentation product lactic acid, were phosphoric acid, α-glycerophosphate, and glycerol from canola;myo-inositol, phosphoric acid, α-glycerophosphate andmyo-inositol-1-phosphate from corn; glycerol, α-glycerophosphate,myo-inositol-1-phosphate, and β-glycerophosphate from cottonseed; phosphoric acid, glycerol, andmyo-inositol from peanut; α-glycerophospho-1-myo-inositol,myo-inositol-1-phosphate, α-glycerophosphate, and glycerol from soybean; and α-glycerophosphate, glycerol,myo-inositol-1-phosphate, and β-glycerophosphate from sunflower.     

氢化葵花油脂肪酸蔗糖酯的合成

以氢化葵花油为原料 ,采用两步法合成了氢化葵花油脂肪酸蔗糖酯。探讨了反应温度、时间、压力、催化剂用量、助熔剂等对蔗糖酯收率的影响规律。结果表明 :当助熔剂和催化剂分别为 30 %和 2 .1%时 ,在 15 0℃下反应 6h ,产物收率达 4 5 %以上。     

Production of FAME from acid oil model using immobilized <Emphasis Type="Italic">Candida antarctica</Emphasis> lipase

Acid oil is a by-product in the neutralization step of vegetable oil refining and is an alternative source of biodiesel fuel. A model substrate of acid oil, which is composed of TAG and FFA, was used in experiments on the conversion to FAME by immobilized Candida antarctica lipase. FFA in the mixture of TAG/FFA were efficiently esterified with methanol (MeOH), but the water generated by the esterification significantly inhibited methanolysis of TAG. We thus attempted to convert a mixture of TAG/FFA to FAME by a two-step process comprising methyl esterification of FFA and methanolysis of TAG by immobilized C. antarctica lipase. The first reaction was conducted at 30°C in a mixture of TAG/FFA (1∶1, wt/wt) and 10 wt% MeOH using 0.5 wt% immobilized lipase, resulting in efficient esterification of FFA. The reaction mixture after 24 h was composed of 49.1 wt% TAG, 1.3 wt% FFA, 49.1 wt% FAME, and negligible amounts of DAG and MAG (<0.5 wt%). The reaction mixture was then dehydrated and used as a substrate for the second reaction, which was conducted at 30°C in a solution of the dehydrated mixture and 5.5 wt% MeOH using 6 wt% immobilized lipase. The activity of the lipase increased gradually when the reaction was repeated by transferring the enzyme to a fresh substrate mixture. The activity reached a maximum after 6 cycles, and the content of FAME achieved was >98.5 wt% after a 24-h reaction. The immobilized lipase was very stable in the first-and second-step reactions and could be used for >100 d without significant loss of activity.     

Microwave-assisted low-cost synthesis of sucrose-soya ester from vegetable oil refinery by-product and its application in toothpaste formulation for oral hygiene

The major drawbacks of the sucrose ester (SE), in spite of being a green nonionic surfactant, are the difficulty of synthesis and higher cost. Distilled soya acid oil (DSAO) obtained as by-product from a vegetable oil refinery was used for the synthesis of fatty acid methyl ester (SAFAME). Microwave-assisted method (680 watts system), which is greener and more efficient was used for the synthesis of SAFAME at 99.3% conversion using 2 wt% sulfuric acid catalyst within 30 min as well as for the synthesis of SE at 82.5% conversion using 5 wt% K₂CO₃ catalyst within 45 min. Both synthesis steps were monitored and characterized by using thin-layer chromatography, gas chromatography, ¹H NMR, and FT-IR. The surface tension of 1% aq. solution of SE was 29.58 mN m⁻¹, while the interfacial tension of n-heptane-1% aq. solution was observed to be 3.29 mN m⁻¹. The critical micelle concentration was 74.24 mg L⁻¹. Foaming properties, emulsion stability, and wetting power were determined by using standard techniques. The SE was used for the development of desensitizing anticavity toothpaste formulation and the various properties were evaluated in comparison with the commercial toothpaste formulation available in the market. The results show that the partially renewable surfactants like sodium dodecyl sulfate (SDS) and sodium lauryl ether sulfate (SLES) can be replaced partially or fully with the biobased renewable SE surfactants in the various personal care formulations including toothpaste.     

Flow and crystallization of saturated fatty acid methyl esters and their binary mixtures

Demand for biodiesel has increased due to being a more environmentally-friendly fuel. Cold weather operation of biodiesel is challenging due to fatty acid methyl ester (FAME) content in biodiesel. Saturated FAMEs crystallize at relatively high temperatures, increase the viscosity of biodiesel, and can clog fuel lines. Here, several factors altered crystallization temperature (CT) of FAMEs, including composition, shear rate, and cooling rate. The crystallization of pure and binary mixtures of methyl palmitate, methyl myristate, and methyl stearate were studied under shear flow and static conditions. Static phase CTs of pure methyl palmitate, methyl myristate, and methyl stearate were 26, 14, and 35°C, respectively. In binary mixtures, CTs were depressed up to 7°C, which agreed with freezing point depression theory. Increasing shear rate up to 100 s⁻¹ decreased CT by 2°C compared to static conditions. Decreasing cooling rate from 1 to 0.1°C/min increased CT less than 2°C. Overall, FAME composition altered CT more than shear flow or cooling rate for pure and binary mixtures of three FAMEs.     

Practical limitations in determining vegetable oil acid values by a novel pH-metric method

A novel pH-metric method is described for the determination of acid values (AV) in vegetable oils without titration. The method is based on a reagent containing triethanolamine, isopropanol, and water to which an oil sample is added before measuring pH. Oil samples with AV in the range 0.006–0.107 mg KOH/g oil were prepared from commercial soybean oil by treatment with a strong-base anion exchanger in OH⁻ form and addition of oleic acid. Compared to the standard titrimetric method, significantly greater AV were obtained at less then 0.02 mg KOH/g oil. This was due to the influence of triethanolamine hydrolysis on the acid-base equilibrium in the mixture “oil-reagent.” Thus, the AV 0.02 mg KOH/g oil is accepted as the limit of quantitation. Because refined oils usually have AV of 0.05 mg KOH/g oil or more, this method should be suitable for practical oil analyses.     

废动植物油生产生物柴油的工程设计

介绍了以废动植物油为原料,在自制新型微酸性DYD催化剂的作用下,通过酯交换反应生成生物柴油的设计过程。根据各个步骤的反应条件及其生产物的特性,结合工业化生产流程的一般规律,通过物性计算,设计出工业化生产工艺流程。结果表明:醇解与酯化转化率达到95.9%,无污染物排放,生物柴油的各项性能指标均达到美国同类产品的标准(D6751-03a),为发展生物柴油探索了一条切实可行的途径。     

氯代甲氧基脂肪酸甲酯增塑性能的研究

本文以不同比例的氯代甲氧基脂肪酸甲酯替代电缆料配方中的增塑剂DOP,考察了电缆料试片的最大力、抗张强度、断裂伸长率及邵氏硬度等指标。试验表明,当DOP为增塑剂总量40%,氯代甲氧基脂肪酸甲酯为增塑剂总量60%时,电缆料材料的各项性能指标均好于100%DOP的电缆料材料,其最大力为375N、抗拉强度为23.78MPa、断裂伸长率为324.42%、邵氏硬度75.86度。当DOP为增塑剂总量20%,氯代甲氧基脂肪酸甲酯为增塑剂总量80%时,电缆料材料的各项指标性能与100%DOP的电缆料材料性能相当。     

地沟油酶法制生物柴油的GC-MS测定

地沟油制的生物柴油成分复杂,通过气相色谱-质谱法测定脂肪酸甲酯、游离脂肪酸的峰形和相对位置,由此可确定各成分的含量,并准确计算出生物柴油的转化率和产率.     

强酸性阳离子树脂催化棕榈油副产物合成脂肪酸甲酯

以强酸性阳离子交换树脂为催化剂,经过自制的固定床反应器,使棕榈油脱臭馏出物(PODD)中的脂肪酸与甲醇起酯化反应,合成脂肪酸甲酯。结果表明,用固定床可从PODD连续制备脂肪酸甲酯,酯化反应的最佳条件为:n(甲醇)/n(PODD)=17.3;反应温度在甲醇正常沸点以下时,温度越高,转化率越大;转化率随催化反应时间增大而增大,但增大速度逐渐趋缓。当在常压下,64℃反应56 min时,游离脂肪酸的转化率可达87%左右。     

Transforming rapeseed oil into fatty acid ethyl ester (FAEE) via the noncatalytic transesterification reaction

A simple methodology for producing biodiesel is presented. The noncatalytic transesterification was carried out via the thermochemical process because the main driving force of biodiesel conversion was temperature rather than pressure. Noncatalytic transformation of rapeseed oil into fatty acid ethyl ester (FAEE) was performed in a continuous flow system under ambient pressure in the presence of activated alumina, charcoal, and carbon dioxide (CO₂). The biodiesel conversion methodology introduced in this work enables the esterification of fatty acids (FFAs), and transesterification of triglycerides to be combined into a single process and leads to a 97.5 (±0.5)% conversion efficiency of biodiesel within 1 min at 420–500^°C. The new process has high potential to achieve a breakthrough in minimizing the cost of biodiesel production owing to its simplicity and technical advantages. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1468–1471, 2013