The kinetics of the esterification reaction between castor oil and oleic acid

In this study, esterification of castor oil with oleic acid was investigated in view of the reaction kinetics under various conditions. Potassium hydroxide,p-toluenesulfonic acid and tin chloride (SnCl₂2H₂O) were used as catalysts. Reaction was carried out at 200°C, 225°C and 250° C by using equivalent proportions of the reactants. For tin chloride, experimental data fitted the second-order rate equation, while for the other catalysts the obtained data fitted the third-order rate equation.     

Mechanism and kinetics of the CoCl2-catalyzed esterification reaction of castor oil with oleic acid

The apparent orders of the Lewis acid-catalyzed esterification reactions between castor oil and oleic acid are known to change with the catalyst used and with the reaction temperature. A mechanism is proposed in this study to explain the variations (with temperature) in the apparent orders of the cobalt chloride-catalyzed esterification reaction between castor oil and oleic acid. According to the proposed mechanism, an acid-catalyst intermediate forms in an initial, fast quasi-equilibrium step, and this intermediate then reacts with the oil to yield the products and to regenerate the catalyst in the rate-determining second step. A general rate expression, with an acid concentration term and a temperature-dependent constant in the denominator, is derived from the proposed mechanism and is verified with data obtained at different temperatures.     

负载型磷钨酸催化杂醇油合成混合酯的研究

本实验以杂醇油和乙酸为原料，杂多酸HPW／MxOy为催化剂。在相同条件下将几种工艺进行比较，从而选出适合该酯化反应的工艺。同时考察了催化剂的用量、醇酸酯比、反应时间等对酯化反应的影响。并研究了杂多酸的重复使用性。确定了酯化率和酯含量最佳时的酯合成反应的工艺条件。     

离子液体催化合成三羟甲基丙烷油酸酯

以离子液体为催化剂,催化三羟甲基丙烷和油酸合成三羟甲基丙烷油酸酯,最佳工艺条件为:醇与酸物质的量比1.1:3,催化剂使用离子液体[C6H10N2]+C2H6O3S-,用量占醇与酸总质量的10%～15%,带水剂为二甲苯,用量占醇与酸总质量的40%,反应温度(150～160)℃,反应时间4.0 h,在此条件下,油酸转化率达...     

Effects of Lewis acid catalysts on the esterification kinetics of castor oil with oleic acid

The effects of two Lewis acid catalysts, tin chloride and cobalt chloride, on the kinetics of the esterification reaction between castor oil and oleic acid have been investigated. Uncatalyzed and catalyzed reactions were carried out both in the presence of excess oil and with equivalent amounts of reactants at various temperatures. The reaction, with respect to castor oil concentration, is first-order in all cases, whereas with acid concentration the reaction was observed to change from second-order for the uncatalyzed reaction to first-order for tin chloride-catalyzed and to zero-order for cobalt chloride-catalyzed reactions. The order (with respect to acid) also changed with temperature for the cobalt chloride-catalyzed reaction.     

固体超强酸SO4^2-/ZrO2-CeO2催化油酸酯化反应的研究

以固体超强酸SO4^2-/ZrO2-CeO2为催化剂,以油酸和甲醇为原料,在高温高压反应釜中进行酯化反应。对反应条件的研究表明,当甲醇与油酸的体积比为2：1（摩尔比为15：1）,反应温度为160℃,反应时间4h,催化剂用量8％（与油酸的质量百分比）时,反应的酯化率达到97．34％。动力学计算表明,该酯化反应的反应级数为1．42,反应活化能为25．25kJ／mol。     

对甲苯磺酸催化制备油酸异丙酯及动力学研究

油酸与异丙醇在对甲苯磺酸催化剂的作用下发生酯化反应制备油酸异丙酯,研究了催化剂用量、醇酸配比、反应时间、反应温度等对转化率的影响。结果表明,催化剂的量4%,醇酸体积比2.5∶1(摩尔比10.3∶1),反应温度75℃,反应时间5 h,酯化率达到91.8%。动力学计算表明,对甲苯磺酸催化制备油酸异丙酯的反应级数为1级,频率因子A=611.1,反应活化能为24.0 kJ/mol。     

Soybean oil microemulsions with oleic acid/glycols as cosurfactants

The preparation of biocompatible microemulsions of soybean oil in systems made of anionic surfactant, oleic acid, water, and several glycols was considered. The selected glycols were ether derivatives (methyl, ethyl, dimethyl, and diethyl ether) of ethylene glycol and diethylene glycol. The study was performed using pseudoternary phase diagrams in which the three apexes were occupied by soybean oil, a combination of surfactant/oleic acid, and a combination of water/glycol, respectively. The widest regions of microemulsions were obtained for systems containing methyl ether and especially ethyl ether of both ethylene glycol and diethylene glycol. The two latter compounds allowed the preparation of oil-in-water, bicontinuous, and water-in-oil microemulsions with final surfactant contents of 3–4%.     

硼酸在润滑油添加剂领域的应用现状

硼元素引入润滑油添加剂中可改善和提高油品的抗磨性能以及热稳定性能等。硼元素是通过硼酸与碱性化合物反应而引入添加剂分子上的，因而，硼酸已逐步成为润滑油添加剂的重要原料之一。介绍了硼酸在润滑油添加剂中的应用现状，包括含硼清净剂、含硼分散剂、含硼极压抗磨剂、含硼防锈剂。主要介绍了世界各大石油公司生产含硼润滑油添加剂的商品牌号、合成方法等。指出随着中国汽车工业的发展，环保、节能法规的不断出台与执行力度的加大，含硼等环保、节能型润滑油添加剂将得到广泛的使用，其中硼化丁二酰亚胺市场潜力巨大。     

油酸异丁酯的合成及其对生物柴油降凝效果研究

油酸与异丁醇在离子液体催化剂的作用下发生酯化反应制备油酸异丁酯。研究了催化剂用量、醇酸配比、反应时间、反应温度等对酯化反应转化率的影响,并通过测定凝固点、冷滤点、粘度来考察脂肪酸异丁酯对生物柴油的降凝效果。结果表明,当催化剂用量为2%,醇酸体积比2∶1(摩尔比6.8∶1),反应温度100℃,反应时间3 h,转化率达到95.6%。降凝实验结果表明,把一定量的脂肪酸异丁酯添加到生物柴油中可有效地降低生物柴油的凝固点、冷滤点,改善其低温流动性能。     

Esterification of oleic acid in soybean oil on zeolite catalysts with different acidity

The catalytic activity of zeolites was studied in the esterification of oleic acid with methanol in soybean oil. The influences of acidity and pore structure of the zeolites were investigated in relation to conversion of the oleic acid on the zeolite catalysts. H⁺ ion exchanged ZSM-5 (HMFI) and mordenite (HMOR) zeolites conducted with different Si/Al ratio were employed to examine an influence of acidity in the reaction. Conversion of oleic acid was about 80% on HMOR zeolites and HMFI(25) zeolite. The conversion of oleic acid was improved as the amount of acid site increased. The amount of acid site of the zeolites affected significantly the catalytic activity in the esterification of oleic acid.     

Esterification of glycerol with conjugated linoleic acid and long-chain fatty acids from fish oil

Free fatty acids from fish oil were prepared by saponification of menhaden oil. The resulting mixture of fatty acids contained ca. 15% eicosapentaenoic acid (EPA) and 10% docosahexaenoic acid (DHA), together with other saturated and monounsaturated fatty acids. Four commercial lipases (PS from Pseudomonas cepacia, G from Penicillium camemberti, L2 from Candida antarctica fraction B, and L9 from Mucor miehei) were tested for their ability to catalyze the esterification of glycerol with a mixture of free fatty acids derived from saponified menhaden oil, to which 20% (w/w) conjugated linoleic acid had been added. The mixtures were incubated at 40°C for 48h. The ultimate extent of the esterification reaction (60%) was similar for three of the four lipases studied. Lipase PS produced triacylglycerols at the fastest rate. Lipase G differed from the other three lipases in terms of effecting a much slower reaction rate. In addition, the rate of incorporation of omega-3 fatty acids when mediated by lipase G was slower than the rates of incorporation of other fatty acids present in the reaction mixture. With respect to fatty acid specificities, lipases PS and L9 showed appreciable discrimination against esterification of EPA and DHA, respectively, while lipase L2 exhibited similar activity for all fatty acids present in the reaction mixture. The positional distribution of the various fatty acids between the sn-1,3 and sn-2 positions on the glycerol backbone was also determined.     

大连石化润滑油基础油酸值不合格解决方案

用大庆尼罗混合减三线脱蜡油为原料,先后进行了工业装置理论塔板数标定、多级静态及中试规模的糠醛溶剂精制实验研究。结果表明,工业装置理论塔板数为2～3块。剂油体积比为6∶1的假二段实验与剂油体积比为3.2∶1的假四段实验精制油酸值均小于0.03mgKOH/g,收率分别为64.53%与75.33%。具有4块理论板数的中试装置在剂油体积比为2.81∶1条件下得到的精制油酸值为0.0246mgKOH/g,收率为78.01%。精制油产品质量能够满足HVI400SN润滑油基础油的质量要求。     

Esterification of oleic acid with glycerol in the presence of sulfated iron oxide catalyst

Esterification of oleic acid with glycerol was investigated in view of the reaction kinetics, using “superacidic” sulfated iron oxide catalysts. A series of different sulfate contents were prepared and characterized by a multitude of techniques prior to their use as catalysts. The sulfated iron oxide reaction was carried out with equivalent amounts of reactants in the temperature range of 180–240°C. Effects of the sulfate content and the catalyst amount on reaction kinetics at different temperatures were evaluated.     

Zirconium sulfate supported on activated carbon as catalyst for esterification of oleic acid by n-butanol under solvent-free conditions

It has been shown that the activated carbon-supported zirconium sulfate (ZS) is an efficient solid catalyst for the esterification of oleic acid by n-butanol under solvent-free condition. The effect of mole ratio of the reactant, time and catalyst loading on the conversion was examined. The correlation among XRD, nitrogen adsorption data and catalytic activity suggested that ZS has been finely dispersed on activated carbon, which are active in the esterification of oleic acid. The reaction shows that the supported ZS exhibits a higher activity than that of parent ZS and conventional resins.     

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。     

Effect of light irradiation on esterification of oleic acid with ethanol catalyzed by immobilized Pseudomonas cepacia lipase

The present study demonstrates the effect of light irradiation on the esterification of oleic acid catalyzed by immobilized Pseudomonas cepacia lipase. The reaction rates of all the experiments under light irradiation were found to be higher than dark conditions. The kinetics of reactions supported the Ping‐Pong Bi‐Bi mechanism with dead end inhibition by both the alcohol and acid substrates. Moreover, circular dichroism (CD) spectroscopy was used to analyze the effect of light on lipase enzyme. The CD spectroscopic studies confirmed that the conformational changes in the secondary structure of the lipase enzyme increased the reaction rate of light‐illuminated experiments, which might have opened up the active sites of enzymes and thus, resulted in higher reaction rates compared to dark reactions. These results have successfully demonstrated that the light illumination positively influenced the rate of P. cepacia enzyme‐catalyzed esterification reactions.     

A twin-screw extruder for oil extraction: II. Alcohol extraction of oleic sunflower seeds

Our work is about the extraction of sunflower seed oil in a twin-screw extruder with or without the injection of 2-ethylhexanol and acidified 2-ethylhexanol. 2-Ethylhexanol is mixed with phosphoric acid. The oil recovery is increased to 90% by the co-injection of acidified alcohol. Mixing phosphoric acid with the alcohol enhances the lability of the oily spherosomes. Its addition increases the destruction of the membranes enveloping the lipid-containing organelles to release the oil more easily. Phosphoric acid exhibits an extracting and a degumming role. The best oil quality was obtained at a low extraction temperature (80°C), when 88% of the oil was removed. After alcoholic distillation, the oil exhibited a total acid value (mineral acidity plus organic acidity) of 4 mg KOH/g of oil and an organic phosphorus content below 30 ppm. This work was presented as an oral communication at the 2nd American Oil Chemists’ Society Europe Symposium, October 1–4, 1998, at Cagliari, Italy.     

A kinetic model for co-oxidation of β-carotene with oleic acid

Oxidation experiments with β-carotene in a lipid solution were conducted under various conditions of temperature, oxygen composition, and lipid content. The experimental results were compared with those using n-decane reported previously. Under all conditions, the oxidation rate in oleic acid was faster than that in n-decane. A novel kinetic model for the co-oxidation of carotene with a lipid was proposed based on the reaction mechanism, which consisted of the oxidation of carotene, the oxidation of oleic acid, and the cross-reaction of carotene with oleic acid. The model quantitatively described the oxidation behavior of carotene over a wide range of temperatures, oxygen compositions, and lipid contents.     

离子液体复配溶剂体系改进壬二酸的合成工艺

以油酸为原料,50%的H2O2为氧化剂,在离子液体作为主要溶剂的条件下,采用钨酸为催化剂所得中间产物用自制的过氧乙酸继续氧化裂解合成了高纯度壬二酸。其中分别对异丙醇、离子液体(BMIMPF6和BMIMBF4)单独作溶剂以及二者复配作溶剂的各种情况作了详细比较。最终经过收率、熔点、FT-IR及HPGC等手段将对上述各产物品质进行了表征与分析,从而得出了合成壬二酸的最佳条件为n(C18H34O2)∶n(H2O2)∶n(H2WO4)=1.0∶3.0∶0.04,V(BMIMPF6)∶V(isopropanol)=1∶0.7,所得中间产物中加入300mL含量为25%的过乙酸在90℃氧化裂解3h。最终壬二酸收率可达46%,纯度高于95%。