超临界CO2萃取共轭亚油酸甘油酯的研究

对超临界CO2萃取分离共轭亚油酸甘油酯进行了研究,考察了温度梯度、压力对萃取过程的影响及萃取对甘油酯分布和酸值的影响.结果表明:当没有温度梯度时,分离速率较快但效果较差;当温度梯度为10℃、压力为12.75～16 MPa时,苹取产物酸值最小为3.94,甘油二酯含量最高为67.08%,所得产物几乎无色.     

无溶剂体系中癸酸甘油酯的酶法合成

本文通过探索无溶剂体系中固定化脂肪酶催化甘油和癸酸酯化合成癸酸甘油酯的反应特性。对无溶剂体系中酶法催化合成中链甘油酯的可行性进行了研究。     

无溶剂体系中酶法催化微藻油脂乙酯化制备生物柴油工艺研究

研究了无溶剂体系中酶法催化微藻油脂乙酯化制备生物柴油的技术工艺,采用Box-Behnken设计及响应面优化了工艺参数。经SAS 9.2软件分析得到的最优条件为:Novozym 435脂肪酶用量6.0%(w/w),醇油摩尔比4.0∶1,温度44.7℃,反应时间17.6 h。在该条件下,乙酯得率达94.86%。同时,获得的较高乙酯转化率为微藻油脂中多不饱和脂肪酸提取奠定了技术基础。     

无溶剂体系中酶法催化微藻油脂乙酯化制备生物柴油工艺研究

研究了无溶剂体系中酶法催化微藻油脂乙酯化制备生物柴油的技术工艺,采用Box-Behnken设计及响应面优化了工艺参数。经SAS 9.2软件分析得到的最优条件为:Novozym 435脂肪酶用量6.0%(w/w),醇油摩尔比4.0∶1,温度44.7℃,反应时间17.6 h。在该条件下,乙酯得率达94.86%。同时,获得的较高乙酯转化率为微藻油脂中多不饱和脂肪酸提取奠定了技术基础。     

无溶剂体系脂肪酶催化制阿魏酸双油酸甘油酯

在无溶剂体系中以分散在硅藻土上的褶皱假丝酵母脂肪酶为催化剂,以阿魏酸乙酯与油酸甘油酯为原料,一步合成阿魏酸双油酸甘油酯。通过质谱和红外光谱对薄层层析分离纯化后的产物结构进行了表征。定量分析表明,当反应温度为50℃,n(阿魏酸乙酯)/n(油酸甘油酯)=1时,阿魏酸双油酸甘油酯的质量占生成物总质量分数较高。在1 mmoL阿魏酸乙酯,1 mmoL油酸甘油酯和70 mg脂肪酶组成的无溶剂反应体系中,50℃空气浴振荡120 h,总产率可达63.32%,其中阿魏酸双油酸甘油酯质量占生成物总质量的63.37%。     

共轭亚油酸锌的合成工艺研究

通过利用共轭亚油酸的弱酸性质,将共轭亚油酸制成盐,以期生理功能的改变,本文利用具有生物功能活性的共轭亚油酸,先与氢氧化钠反应得到共轭亚油酸的钠盐溶液,再加入氯化锌溶液得到共轭亚油酸锌盐,平均收率为67%。为共轭亚油酸锌制成制剂的进一步研究提供了原料。     

硫酸氢钠催化合成共轭亚油酸的反应动力学

常压下,以蓖麻油为原料,硫酸氢钠为催化剂,对合成共轭亚油酸的反应动力学进行了研究,分析了搅拌速度、反应时间、催化剂的用量对反应转化率的影响。结果表明,蓖麻油酸异构化反应为一级反应,反应活化能为18.060 kJ/mol,动力学方程为r C=35.943 e-18.060/RT C A。     

共轭亚油酸盐的研究进展

本文通过共轭亚油酸的结构、生理功能,引出了共轭亚油酸盐的应用。并分别从共轭亚油酸的钙盐、锌盐、镁盐、钠盐和钾盐的应用出发综述了近年来有关共轭亚油酸盐的研究进展,阐述了其广泛的开发应用前景。     

偏铁酸钠催化合成共轭亚油酸

以红花菜籽油中亚油酸为原料,偏铁酸钠为催化剂,在单因素试验的基础上,选取反应温度、反应时间、催化剂用量为考察因素,以异构化产物共轭亚油酸(CLA)转化率为响应值,通过响应面分析法对异构化反应进行优化,并建立相应的回归模型,试验结果表明,红花菜籽油中亚油酸异构化为CLA的最佳工艺为：反应温度195℃、反应时间4.7 h、催化剂用量0.6 g,在此条件下得到CLA转化率为92.90%,与预测值93.92%相比,误差为1.02%。然后再通过脲素包合纯化、经2%的H₂SO₄-CH₃OH溶液甲酯化后,用气相色谱-质谱联用仪检测CLA含量为64.27%。     

共轭亚油酸乙酯的合成

采用间歇式反应 ,以硫酸、磷酸、对甲苯磺酸为催化剂对共轭亚油酸乙酯进行了合成 ,并采用正交实验设计研究了物料比、反应温度、反应时间、催化剂用量对产品收率和品质的影响。硫酸、对甲苯磺酸催化活性佳 ,磷酸催化活性差。得到了如下合成工艺条件 :硫酸催化 ;n(共轭亚油酸 )∶n(无水乙醇 ) =1∶6;酯化反应温度 76℃ ;反应时间 1h ;催化剂用量为共轭亚油酸质量的 2 5 % ,收率可达 75 % ,产品w(共轭亚油酸乙酯 ) =77%～ 82 %。     

非水相脂肪酶催化阿魏酸淀粉酯合成

以玉米淀粉和阿魏酸乙酯为原料,利用脂肪酶催化合成阿魏酸淀粉酯。对反应介质和脂肪酶进行了筛选,同时对影响合成阿魏酸淀粉酯反应的因素进行了探究,主要考察了底物摩尔比、酶添加量、反应时间及反应温度等参数对该反应的影响。采用紫外分光光度计对取代度进行测定,并以取代度为考察指标,确定了最佳反应条件：Novozym435脂肪酶为催化剂、异辛烷为反应介质、底物摩尔比为3:1、酶添加量为10%、反应时间18 h、反应温度65 ℃,在此条件下,产物的最大取代度可达0.031. 并通过FT-IR以及1H NMR对产物进行表征。     

脂肪酶选择性水解酰胺工艺条件的初步研究

对脂肪酶Nov435选择性水解拆分2-氯-N-(1-(4-氯苯基)乙基)乙酰胺的工艺进行了研究.通过对反应介质、转化时间、底物浓度、温度和转速等影响因素的考察,得到较优的拆分工艺为:反应介质为含水体积分率为0.2%的甲苯,酶添加且0.04 g/mL,底物浓度为0.3%,反应温度40℃,转速为220 r/min,转化时间...     

超声酶促合成氯乙酸对硝基苄酯研究

以氯乙酸和对硝基苄醇为原料,超声辅助固定化脂肪酶催化合成氯乙酸对硝基苄酯,并对超声酶促合成条件进行了优化。实验结果表明:20 Hz的超声声强为0.5 W·cm-2,温度为35℃,固定化酶的浓度为2 g·L-1时,反应6 h,对硝基苄醇的转化率最高可达89.7%。     

Lipase-Catalyzed Synthesis of Fatty Acid Pyridylcarbinol Ester for the Analysis of Seed Lipids

Numerous derivatives of fatty acids (FA), including esters of methanol/3‐hydroxymethylpyridine or dimethyloxazoline, are used for the analysis of FAs in biological specimens. Picolinyl derivatives are frequently prepared for structural determination by gas chromatography–mass spectrometry (GC‐MS) since they provide characteristic fragments. The ester can be prepared by chemical methods‐multistep methodologies or basic transesterification. Microbial lipases catalyze a number of transesterification reactions, and their catalytic activities are often stable at extreme conditions. Although these characteristic features may be useful in the application of typical FA structure analysis by picolinyl ester, detailed studies have not been reported. To address the problems, a simple and quantitative methodology for the synthesis of picolinyl esters from lipids has been developed. It involves the transesterification with Novozym 435 (Novozymes Biopharma US Inc., Franklinton, USA), resin‐immobilized lipase from Candida antartica in toluene. Mild reaction conditions allow for complete derivatization of perilla seed oil in 30 min at 50 °C. The procedure was further studied with various TAGs and fatty wax from 17 plants. The optimized procedure was as follows; 1 mg lipid and 20 mg catalyst in 2 mL toluene at 50 °C for 1 h. Quantitative analysis of marker FAs was performed with the proposed method. The results coincided well with those from potassium t‐butoxide‐catalyzed reaction. The optimized method, however, was not applicable for the determination of some epoxy FAs, fatty wax, and parinaric acid.     

Lipase-catalyzed esterification of lactic acid with straight-chain alcohols

Enzymatic synthesis of esters of lactic acid and straight-chain alcohols with different chain lengths (C₆–C₁₈) were investigated in batch reactions with hexadecanol (C₁₆) as the model alcohol. Cyclohexane was the best solvent for higher ester yields, and the best biocatalyst was the immobilized Candida antarctica lipase B (Novozym 435) as well as the textile-immobilized Candida sp. lipase. A method was established to obtain ester yields in the range of 71 to 82% for the different alcohols, and the most favorable conditions for the esterification reaction using Novozym 435 were an equimolar ratio of lactic acid to alcohol, each at a concentration of 120 mM each; a 50°C reaction temperature; 190 rpm shaking speed; and the addition of 100 mg molecular sieves (4 Å) for drying. The ester yield increased with increasing lipase load, and a yield of 79.2% could be obtained after 24 h of reaction at 20 wt% of Novozym 435. The immobilized Candida sp. lipase prepared in the laboratory also could be used to produce esters of lactic acid and straight-chain alcohols, but it had a much lower activity than Novozym 435 with a temperature optimum of 40°C.     

Improved Synthesis of Monopalmitin on a Large Scale by Two Enzymatic Methods

Monoacylglycerols (MAG) are precursors for the synthesis of symmetrical and unsymmetrical triacylglycerols (TAG). In the present study, we improved two methods for synthesizing MAG. One method involved the enzymatic transesterification of vinyl palmitate with glycerol catalyzed by Novozym 435 lipase, and the other method was an enzymatic esterification of 1,2-acetonide glycerol with palmitic acid catalyzed by Novozym 435 lipase and then the cleavage of 1,2-acetonide-3-palmitoyl glycerol in methanol catalyzed by Amberlyst-15 to produce monopalmitin. Pure monopalmitin was obtained after repeated crystallization. The main novelties of this study are twofold: Novozym 435 proved to be very effective in catalyzing the transesterification between vinyl palmitate and glycerol without absorbing glycerol onto silica gel; and the enzyme catalyzed reaction between 1,2-acetonide glycerol and palmitic acid was simpler and safer than the typical method of using 4-dimethyl aminopyridine and N-ethyl-N′-(3-dimethylaminopropyl)-carbodiimide hydrochloride as catalysts. Our methods for the synthesis of monopalmitin are much simpler and environmentally friendlier than the reported methods, and they are economical and scalable to larger quantity production.     

有机相中酶催化1-苯基乙胺的不对称酰胺化反应

在有机相中,对酶催化条件下的1-苯基乙胺酰胺化反应进行了研究。通过对酰基供体、酶、溶剂的筛选和酯量、底物胺浓度、酶量、摇床转速、反应温度等影响因素的考察,发现乙酸异丙烯酯为较佳的酰基供体,脂肪酶Novozym 435对该反应的催化活性和对映体选择性较高,甲苯为最适的介质,最适酯量为底物胺量的0.6倍,最佳底物胺浓度、酶量、摇床转速、温度分别为200 mmol·L^-1、4 mg·ml^-1、200 r·min^-1、30℃。在此优化条件下反应的对映体选择率（E）达到89。反应4 h转化率为39％,产物的对映体过剩值（ee_p）为96％;反应10 h转化率达到52.4％,底物的对映体过剩值（ee_s）为98％。     

Production of geranyl propionate by enzymatic esterification of geraniol and propionic acid in solvent‐free system

Background: This work reports the optimization of geranyl propionate production by esterification of geraniol and propionic acid in a solvent‐free system using a commercial lipase as catalyst. For this purpose, a sequential strategy was performed applying two experimental designs. Results: The operating conditions that optimized geranyl propionate production were determined to be 40 °C, geraniol to propionic acid molar ratio of 3:1, 150 rpm and 10 wt% of enzyme, with a resulting reaction conversion of about 93%. After determining the optimum reaction parameters, a kinetic study was carried out evaluating the influence of substrates molar ratio, enzyme concentration and temperature on reaction conversion. Results obtained in this step allow one to conclude that an excess of alcohol (acid to alcohol molar ratio of 1:6), relatively low enzyme concentration (5 wt%), temperature of 40 °C and substrates molar ratio of 1:1 afforded nearly complete reaction conversion after 30 min of reaction. Conclusion: New experimental data on enzymatic esterification of geraniol and propionic acid for geranyl propionate production are reported in this work, showing a promising perspective of the technique to overcome the well‐known drawbacks of the chemical‐catalyzed route. Copyright © 2010 Society of Chemical Industry     

酰基供体对动态动力学拆分1-四氢萘胺的影响

采用新型消旋催化剂耦合Novozym 435成功构建1-四氢萘胺的动态动力学拆分体系用于制备光学纯(R)-1-四氢萘胺。该反应存在着自催化酰胺化反应,会降低反应的对映体选择性。从改变酰基供体结构的角度出发来抑制这种自催化酰胺化反应,考察了不同酸部以及不同醇部的酰基供体对1-四氢萘胺动态动力学拆分反应的影响,发现随着酰基供体结构变得复杂,1-四氢萘胺动态动力学拆分反应结果也相应变得越好,当采用戊酸对氯苯酯作为酰基供体时,动态动力学拆分反应结果就可达到最佳,即转化率>99%,光学纯度eeP>99%。     

Novozym435催化不对称水解3-(4-氟苯基)-戊二酸二甲酯的动力学研究

对Novozym 435在以甲基叔丁基醚(MTBE)为助溶剂的水相体系中不对称水解3-(4-氟苯基)-戊二酸二甲酯(3-DFG)的动力学进行了研究。考察了摇床转速、酶浓度、底物浓度、产物浓度等因素对该水解反应的影响。结果表明该水解反应的最佳转速为200 r?min?1,内扩散的影响可忽略。底物3-(4-氟苯基)-戊二酸二甲酯和产物3-(4-氟苯基)-戊二酸单甲酯(3-MFG)对Novozym 435的催化水解活性不存在抑制作用。此外,该反应受副产物甲醇的竞争性抑制,通过非线性回归求得该体系相应的动力学参数值:米氏常数Km值为0.24 mol?L?1,抑制常数Ki值为0.39 mol?L?1,最大反应速度Vmax值为2.39 mmol?L?1?h?1。