铜绿假单胞菌脂肪酶无溶剂催化棕榈油甘油解：Ⅰ.单甘酯酶促合 …

以自产铜绿假单胞菌脂肪酶为催化剂,通过无溶剂法棕榈油甘油解反应催化合成的单脂肪酸甘油酯。实验结果表明：适宜加酶量为５００ｕ／ｇ棕榈油,甘油相适宜水质量分数为ｗ（Ｈ２Ｏ）＝３％～４．５％,反应物量比宜设定为ｎ（甘油）：ｎ（棕榈油）＝（２．０～２．５）：１。反应器材质对单甘酯产率有影响,３１６Ｌ型不锈钢为适宜材质。最佳反应温度为３８～４２℃,在此温度区间内适宜反应时间为２４ｈ。临界反应温度为４４℃。     

CaCO_3粉末作载体固定化脂肪酶催化合成单甘酯

研究了以CaCO3 粉末为载体吸附法固定化脂肪酶的方法。结果表明 ,当酶的用量为CaCO3 质量的 0 3g g-1,吸附时间 1 5h ,所得固定化酶活最高 ,为 15 8 1UCaCO3/g min。研究了固定化酶催化棕榈油固相甘油解反应合成单甘酯工艺条件 ,结果表明 ,固定化酶加入量为 15 0U/g油 ,甘油与棕榈油摩尔比为 4∶1,甘油中水的含量为 4% ,于2 8℃反应 2 4h ,然后将反应体系的温度降至室温 ( 13℃～ 15℃ ) ,9天后单甘酯的含量达 33 4% ,该固定化酶很容易从反应体系中回收 ,重复使用 5次 ,酶活保留 73 37%     

连续加压炔化反应合成脱氢芳樟醇

研究了以液氨为溶剂 ,在反应温度 35～ 4 0℃ ,压力 2 0～ 2 5MPa的条件下 ,6 甲基 5 庚烯 2 酮连续加压乙炔化反应制备脱氢芳樟醇工艺 ,考察了反应时间、物料量比对反应的影响 ,并对反应机理作了初步探讨。实验表明 ,反应温度 35～ 4 0℃ ,压力 2 0～ 2 5MPa ,n (6 甲基 5 庚烯 2 酮 )∶n (催化剂 )∶n(乙炔 )∶n(液氨 ) =7∶1∶5 1∶15 3,反应时间为 2 1h ,脱氢芳樟醇收率为 92 %～ 94 % ,产品经减压精馏后 ,脱氢芳樟醇质量分数大于 98%     

复合固体超强酸SO42-/ZrO2-TiO2催化合成三乙酸甘油酯

用复合固体超强酸SO_4~(2-)/ZrO_2-TiO_2催化合成三乙酸甘油酯。考察了合成三乙酸甘油酯的适宜工艺条件为:催化剂用量为2.5%～3.0%(占总投料量质量分数),投料比为n(甘油)∶n(乙酸)=1∶5.5,反应温度130℃,反应时间3.0h。在适宜的工艺条件下产品收率达92.6%,催化剂可重复使用6次,易再生。     

酶催化合成高纯度甘油中碳酸单酯

研究了无溶剂体系中脂肪酶LRI催化合成甘油中碳酸单酯(MG)。得到适宜的反应条件为:反应温度57℃,n(酸)∶n(甘油)=1∶1 1,加酶量100U/g(酸),甘油初始含水量w(H2O)=12%,封闭物系反应4h转敞开物系反应6h。产物中甘油中碳酸单酯质量分数w(MG)=42 20%。将n(酸)∶n(甘油)降低至1∶9,反应时间缩短至4h,粗产物经脱甘油和脱酸处理,可获得高纯度甘油中碳酸单酯。纯化后产品中基本不含游离酸及甘油,其中甘油中碳酸单酯质量分数w(MG)=73 65%。过量加入的甘油全部可以回收利用,其平衡转化率降低不超过2%。     

过碱性硫化壬基水杨酸钙清净剂的开发

通过金属化、羧基化、硫化等步骤 ,进行了过碱性硫化壬基水杨酸钙清净剂的开发研究 ,得到较为适宜的原料量比为 :n(氧化钙 )∶n(壬基酚 ) =0 .5∶1 0 ,n(乙二醇 )∶n(氧化钙 ) =( 0 .8～1 0 )∶1 0 ,n(硫 )∶n(氧化钙 ) =( 1.0～ 1.2 )∶1 0 ;各步骤适宜的操作参数为 :①金属化 :温度 16 0℃ ,压力 (N2 )常压 ,时间 4h ;②羧基化 :温度 2 0 0℃ ,压力 (CO2 ) 0 .6～ 0 .8MPa ,时间 2h ;③硫化 :温度 180℃ ,压力 (CO2 ) 0 6MPa ,时间 3～ 4h。产品总碱值达到 183mgKOH/g。     

一锅法合成苯甲醛缩氨基脲

以水合肼、尿素和苯甲醛为原料 ,一锅法合成苯甲醛缩氨基脲 ,该工艺中间产物氨基脲不以氨基脲盐酸盐形式分离 ,直接与苯甲醛进行缩合反应 ,且不产生含肼废水。适宜的反应条件为 :n (H2 NNH2 ·H2 O)∶n (H2 NCONH2 )∶n (C6H5CHO) =1 0∶2 0∶0 8,氨基脲合成反应温度 98～ 10 1℃ ,反应时间 3～ 4h ;缩合反应pH =3～ 4 ,滴加时间 1 5h ,室温搅拌 2h ,回流 1h ,产物收率为 98.0 %。     

酯交换法合成共轭亚油酸三甘酯

采用酯交换反应,以共轭亚油酸乙酯、甘油为原料,脂肪酸钾为均相化试剂,无水K2CO3为催化剂,在压力～1 0kPa下反应制得共轭亚油酸三甘酯。合成工艺条件:n(共轭亚油酸乙酯)∶n(甘油)=6∶1;酯化反应温度140℃;反应时间～1 5h;无水K2CO3用量为共轭亚油酸乙酯质量的0 5%～1%;按统计平均值,产物三甘酯脂肪酸侧链中w(共轭亚油酸)>80%;产率(以甘油计)60%～65%。     

由喜树碱制备盐酸拓扑替康

以喜树碱(CPT)为原料,采用氧化、光化及Mannich3步反应的路线合成了盐酸拓扑替康(TPT),通过对反应条件的优化,确定氧化反应最佳条件为:反应时间4h、反应温度75℃、0 01mol喜树碱,w(H2O2)=30%的双氧水48mL、乙酸350mL;光化反应条件:V(1,4 二氧六环)∶V(乙腈)∶V(H2O)=5∶4∶1为溶剂,浓硫酸为催化剂;Mannich反应条件:n(羟基喜树碱)∶n(甲醛)∶n(二甲胺水溶液)=1∶9 3∶5 5,反应温度45℃。盐酸拓扑替康总收率35 9%(文献值[4]29%)、w(TPT)=98 50%、熔点213～217℃(文献值[6]213～218℃)。     

载体强酸催化合成柠檬醛二乙缩醛

研究了以复合载体强酸 (Ph SO3H/Na2 SO4·CaSO4)催化合成柠檬醛二乙缩醛的新方法 ,得到柠檬醛直接与无水乙醇一步反应的最佳条件 :投料比n(柠檬醛 )∶n(无水乙醇 )∶n(苯磺酸 ) =1∶ (4～ 5 )∶(0 .0 2 5～ 0 .0 0 3 0 ) ,控制反应温度 80℃ ,反应时间 1 .5h。该优化条件下 ,合成收率为 93 %～ 94% ,粗成品纯度可达 96 %     

Lipase-catalyzed glycerolysis of olive oil in organic solvent medium: Optimization using response surface methodology

Enzymatic glycerolysis of olive oil for mono- (MG) and diglycerides (DG) synthesis was investigated. Several pure organic solvents and co-solvent mixtures were screened in a batch reaction system. The yields of MG and DG in co-solvent mixtures exceeded those of the corresponding pure organic solvents. Batch reaction conditions of the glycerolysis reaction, the lipase amount, the glycerol to oil molar ratio, the reaction time, and temperature, were studied. In these systems, the high content of reaction products, especially MG (55.8 wt%) and DG (16.4wt%) was achieved at 40 °C temperature and 0.025 g of lipase with relatively low glycerol to oil molar ratio (2: 1) within 4 h of reaction time in isopropanol/tert-butanol (1: 3) solvent mixture. Glycerolysis reaction was optimized with the assistance of response surface methodology (RSM). Optimal condition for reaction conversion was recommended as lipase amount 0.025 g, glycerol to oil molar ratio 2: 1, reaction time 4 h and temperature 40 °C.     

脂肪酶促乌桕脂组分甘油解及其反应机理研究

Glycerolysis of Chinese vegetable tallow （CVT） fraction was investigated using a 1,3-specific lipase from Rhizopus arrhizus as catalyst. Based upon a binary gradient HPLC with an evaporative light-scattering detector （ELSD）, the contents of free fatty acids （FFA）, monoglycerides （MG）, diglycerides（DG） and triglycerides （TG） with their positional isomers during the glycerolysis were determined. The effects of water content and the ratio of glycerol to oil on the product distribution of glycerolysis were studied. Under the optimum reactant conditions： 250 units lipase per gram oil at 37℃ with 1：2 molar ratio of oil to glycerol in a solvent-free system, after 24 h reaction, the product consisted of 7.2% TG, 25.6% MG, 56.1% DG and 4.9% FFA （all by mass）. Furthermore, the mechanism of glycerolysis was discussed in detail.     

铜绿假单胞菌脂肪酶无溶剂催化棕榈油甘油解Ⅱ.进一步提高单甘酯产率的研究

以自产铜绿假单胞菌脂肪酶为催化剂 ,通过无溶剂法棕榈油甘油解反应催化合成了单脂肪酸甘油酯。考察了反应温度程序以及加酶方式对最终产物中单甘酯质量分数的影响。结果表明程序降温和批次加酶更有利于反应 ,产物中单甘酯质量分数可增大 1 0 %～ 2 0 % ,实验条件下反应 48h后单甘酯质量分数可达 65 % ,脱酶后达 77%。     

Immobilization of Candida antarctica lipase onto cellulose acetate-coated Fe2O3 nanoparticles for glycerolysis of olive oil

Candida antarctica lipase was covalently immobilized onto the surface of cellulose acetate-coated Fe₂O₃ nanoparticles. The characterizations of immobilized lipase were examined by Fourier transform infrared spectrophotometer (FTIR) and field emission gun-scanning electron microscopy (FEG-SEM). The immobilized lipase was assayed for production of monoglycerides (MG) and diglycerides (DG) by glycerolysis of olive oil in a solvent medium. The effect of various reaction conditions on the MG and DG production such as reaction time, temperature, the molar ratio of glycerol to oil and amount of immobilized lipase was investigated. The optimum condition for MG and DG production was found at 50 °C temperature and 0.025 g of lipase with the molar ratio of glycerol to oil 1.5: 1 in 5 h of reaction time. The effect of substrate concentration on enzymatic activity of the free and immobilized lipase showed the best fits to the Lineweaver-Burk plots. The K _m and V _max values of immobilized lipase were found to be 25mM and 0.58mM/min, whereas that for free lipase was 52.63mM and 1.75mM/min, respectively. The activation and deactivation energy was found to decrease for immobilization of lipase on cellulose acetate-coated Fe₂O₃ nanoparticles.     

A continuous process for the glycerolysis of soybean oil

A continuous process for the glycerolysis of soybean oil with pure and crude glycerol, the co-product from the transesterification of soybean oil, was investigated in a pilot plant. The process was equipped with a static and a high-shear mixer. The experimental studies explored the effects of variations in mixing intensity, temperature, reactant flow rates, and reactant stoichiometry on the formation of MG and DG. The developed process resulted in high conversion of TG to MG. The most favorable conditions were 230°C, 40 mL/min total flow, 25 min of reaction time, 2.5∶1 molar ratio of glycerol/soybean oil, and 3600 rpm for the reactions involving crude glycerol where the concentrations of MG and DG in the product were about 56 and 36 wt%, respectively. Under similar conditions, glycerolysis of pure glycerol resulted in 58% MG and 33% DG. In general, higher temperatures and mixing intensities favored the conversion of TG to MG and DG. Reaction temperature had a greater influence on the extent of the reaction than mixing. The formation of MG approached equilibrium for nearly all cases under investigation.     

Selective distribution of saturated fatty acids into the monoglyceride fraction during enzymatic glycerolysis

Four triglyceride fats and oils (beef tallow, lard, rapeseed oil and soybean oil) were reacted with glycerol while using lipase as the catalyst. For all fats examined, at reaction temperatures above the critical temperature (T_c), the fatty acid compositions of the monoglyceride (MG) and diglyceride (DG) fractions and of the original fat were similar. A relatively low yield of MG was obtained (20–30 wt%). When the reaction was carried out with beef tallow or lard at a temperature below the T_c (40°C), the concentration of saturated fatty acids in the MG fraction was 2 to 4 times greater than that in the DG fraction. Correspondingly, the concentration of unsaturated fatty acids in the DG fraction was more than two times greater than that in the MG fraction. At 5°C, a similar trend was observed for rapeseed oil and soybean oil. Direct analysis of partial glycerides during glycerolysis by high-temperature gas-liquid chromatography showed that below T_c the content of C16 MG increased relatively more than C18 MG. C36 DG and C54 TG were apparently resistant to glycerolysis. Preferential distribution of saturated fatty acids into the MG fraction was accompanied by a high yield of monoglyceride (45–70 wt%) and solidification of the reaction mixture. It is concluded that during glycerolysis below T_c, preferential crystallization occurs for MGs that contain a saturated fatty acid.     

无溶剂酶催化油脂甘油解中温度效应的研究

以荧光假单胞菌脂肪酶为催化剂 ,进行无溶剂油脂甘油解反应合成单脂肪酸甘油酯。实验结果表明 :反应 2 4h时在所有实验体系中 ,反应温度高于 46℃时 ,产物中单甘酯平衡质量分数均低于 30 % ,最佳反应温度与体系最低共熔点有关。当体系最低共熔点约在 35～ 45℃时 ,临界温度 (TC)现象较明显 ,最佳反应温度接近于此反应体系的最低共熔点。油脂熔点和体系最低共熔点低于 35℃时 ,最佳反应温度及临界温度高于最低共熔点 ;油脂熔点和体系最低共熔点高于 45℃时 ,最佳反应温度低于最低共熔点。提出了第一临界温度和第二临界温度的概念     

Enzymatic glycerolysis of soybean oil

Enzymatic glycerolysis of soybean oil was studied. Of the nine lipases that were tested in the initial screening, Pseudomonas sp. resulted in the highest yield of monoglycerides. Lipase from Pseudomonas sp. was further studied for the influence of temperature, thermal stability, enzyme/oil ratio, and glycerol/oil ratio. A full factorial optimization approach was performed. The following conditions were tested over the specified ranges: temperature (30–70°C), thermal stability (30–70°C), enzyme/oil ratio (0.05–0.2 g enzyme/10 g oil), glycerol/oil ratio (1:1–3:1 glycerol/oil molar ratio) and 1 h reaction time. The stability of the enzyme at the reaction temperature was also incorporated as a separate variable. At temperatures above 40°C enzyme denaturation offset the higher activity. The optimal conditions were selected to be the basis for a continuous process: 40°C, a glycerol/oil molar ratio of 2:1, and an enzyme/oil ratio of 0.1 g enzyme/10 g oil. A definition for glycerolysis activity was adopted. The glycerolysis activity (1 GU) was defined as the amount of enzyme necessary to consume 1 μmol of substrate (glycerol and oil) per minute. This research is intended to explore the reaction parameters that are important in a continuous enzymatic glycerolysis process.     

Enzymatic glycerolysis of a triglyceride in aqueous and nonaqueous microemulsions

Enzymatic solvolysis of a model triglyceride, palm oil, was performed in microemulsions containing isooctane, sodiumbis(2-ethylhexyl)sulfosuccinate (AOT), palm oil and a combination of water and glycerol as the polar component. Using a 1,3-specific lipase both hydrolysis, leading to the formation of fatty acid and one mole of monoglyceride, and glycerolysis, giving three moles of monoglyceride, occur. The reaction was very slow in a completely nonaqueous system. Addition of a small amount of water led to an increased rate of glycerolysis, in addition to hydrolysis. It was found that by using³H labelled material reaction products originating from the two reactions were formed in equimolar amounts. The products probably emanate from a common intermediate. The molar ratio, R, of water and glycerol to surfactant turned out to be critical, optimum R-value being 3.4. Four different lipases, one from porcine pancreas and three of fungal origin, were tested. No marked differences in ratio of monoglyceride to fatty acid formed were obtained, indicating that the ratio between glycerolysis and hydrolysis is constant regardless of the lipase used.     

Glycerolysis of Buriti Oil (Mauritia flexuosa) by Magnesium Oxide and Immobilized Lipase Catalysts: Reaction Yield and Carotenoids Degradation

Buriti (Mauritia flexuosa) is a palm tree widely distributed in South America. The oil extracted from its fruit is an added value product for its high carotenoids content. The aim of this work was to evaluate the alkaline (magnesium oxide—MgO) and enzymatic (lipase B from Candida antarctica immobilized on macroporous acrylic resin) glycerolysis of buriti oil to obtain non-ionic emulsifiers and evaluate the carotenoids degradation during this process. Alkaline glycerolysis was carried out using a 3:1 glycerol/oil molar ratio, temperatures of 170 and 210 °C, and MgO contents of 0.5 and 1%wt. Enzymatic glycerolysis reactions were performed using 3%wt. of a lipase catalyst and varying the following parameters: glycerol: oil molar ratio (3:1, 6:1, and 9:1), solvent (tert-butyl alcohol) concentration (50%, 150%, and 250%, vol./substrate mass), and temperature (40, 55 and 70 °C). The products were analyzed by liquid chromatography and UV–visible spectroscopy (370–520 nm). Enzymatic glycerolysis was superior in terms of conversion and selectivity to monoacylglycerols (MAG). MAG yields were close to 80% or higher for most conditions tested for enzymatic glycerolysis, while the maximum yield for alkaline glycerolysis was of 58%. UV–Vis data showed that carotenoids were severally degraded in alkaline glycerolysis, while the enzymatic product exhibited high preservation of carotenoids and color and odor similar to those of the pure buriti oil. Based on the final composition of the non-ionic emulsifiers obtained from buriti oil by enzymatic glycerolysis, they can be considered potential raw materials for cosmetic and food industries.