Preparation, Characterization and Catalytic Performance of La-SO_4^(2-)/SBA-15 in Esterification of Acetic Acid with n-Butanol

La-SO42-/SBA-15 was synthesized with various amounts of lanthanum via incipient-wetness impregnation. Characterization was done by X-ray diffraction（XRD）, transmission electron micrographs（TEM）, nitrogen adsorption, FTIR spectroscopic analysis, thermogravimetric analysis, and the total amount of acidity of catalyst was estimated by TPD of NH3. The results indicate that lanthanum has been incorporated into SBA-15 molecular sieve. The prepared materials（La-SO42-/SBA-15） keep the highly ordered mesoporous two-dimensional hexagonal structure and do not change the mesoporous channel structure of the support SBA-15. The catalyst showed best catalytic activity in the synthesis of n-butyl acetate. The optimum conditions of the esterification by orthogonal experiments were studied： the molar ratio of n-butanol to acetic acid 1：1.2, the amount of catalyst 7.5%, reaction time 80 min. The yield of n-butyl acetate could reach 93.2% under the optimum conditions. The catalyst was recyclable, cost effective and environmental friendly.

Enantioselective esterification of(R,S)-2-(4-methylphenyl)propionic acid via Novozym 435:Optimization and application

This paper reports on the resolution of(R,S)-2-(4-methylphenyl)propionic acid(MPPA)enantiomers by enzymatic esterification in organic solvent.Novozym 435(CALB)has the best catalytic performance compared with other lipases.Of the alcohols screened,n-hexanol is the best acyl acceptor and gives the highest enzyme activity and enantioselectivity in n-hexane.Response surface methodology(RSM)was used to evaluate the influence of the factors,such as temperature,enzyme amount,substrate concentration and reaction time on the substrate conversion(c)and enantiomeric excess(ee).The correlation coefficient R2 for enantiomeric excess and the conversion are 0.9827 and 0.9910,respectively,indicating that can accurately predict the experimental results.By simulation and optimization,the optimal conditions were obtained,involving 600 mmol·L^-1 MPPA concentration(0.60 mmol),850 mmol·L^-1 hexanol concentration(0.85 mmol),58 mg enzyme amount,75℃temperature and 4.5 h reaction time,respectively.Under the optimized conditions,the experimental values of conversion and enantiomeric excess were 89.34%and 97.84%,respectively,which are in good agreement with the model predictions.

三甘醇双[3-(3′,5′-二叔丁基-4′-羟基苯基)丙酸]酯的合成与表征

以3-(3′,5′-二叔丁基-4′-羟基苯基)丙酸甲酯和三甘醇为原料,有机锡为催化剂,通过酯交换法在甲苯作溶剂的条件下合成了三甘醇双[3-(3′,5′-二叔丁基-4′-羟基苯基)丙酸]酯。通过实验考察了反应温度、催化剂及催化剂用量、反应时间及物料配比等因素对反应的影响。结果表明,最佳反应条件为:反应温度120～125℃,催化剂为有机锡,催化剂用量0.25g,反应时间3.5h,3-(3′,5′-二叔丁基-4′-羟基苯基)丙酸甲酯与三甘醇物质的量比为2.10∶1,在此条件下,产物收率在94%以上,产品熔点为106～107℃,通过元素分析、红外光谱分析、核磁氢谱对产品结构进行了表征。

N,N′-双[3-(3′,5′-二叔丁基-4′-羟基苯基)丙酰]己二胺的合成新工艺

以 3- (3′,5′-二叔丁基 - 4′ -羟基苯基 )丙酸甲酯 (简称 3,5 -甲酯 )与己二胺为原料 ,有机锡为催化剂 ,二甲苯为溶剂合成了N ,N′ -双 [3- (3′,5′ -二叔丁基 - 4′ -羟基苯基 )丙酰 ]己二胺。通过实验考察了反应温度、催化剂及催化剂用量、反应时间及物料配比等因素对反应的影响。结果表明 ,最佳的反应条件是 :反应温度为 135～ 14 5℃ ,催化剂为有机锡 ,用量为 3,5 -甲酯的 2 % ,反应时间为 3.5h ,3,5 -甲酯与己二胺物质的量比为 2 .10 ∶1。在此条件下 ,收率在 97%以上 ,放大到 10 0 0mL ,收率在 99%以上 ,产品熔点为 16 1～ 16 2℃ ,产品纯度较高 ,通过元素分析、红外光谱分析。

Preparation,characterization and catalytic properties of S_2O_8^(2-)/ZrO_2-CeO_2 solid superacid catalyst

A novel solid superacid catalyst S2O8^2-/ZrO2-CeO2 was prepared by a coprecipitation method and characterized by means of XRD FTIR, BET, TEM and DSC/TG analysis methods. The results indicated that incorporation of appropriate amounts of Ce into the catalyst was beneficial to the formation of sole tetragonal ZrO2 and effectively prevented from the formation of monoclinic ZrO〉 and restrained the loss of sulfated species. XRD revealed the presence of tetragonal Ce0.16Zr0.84O2phase in the case of S2O8^2-/ZrO2-CeO2 calcined above 500 ℃. Catalytic activities of S2O8^2-/ZrO2-CeO2 for the esterification of lactic acid with n-butanol was studied. The results showed that the optimum conditions were as follows： calcination temperature of the catalyst 600 ℃, n（lactic acid）：n（n-butyl alcohol）=1.0：3.0, w（S2O8^2-/ZrO2- CeO2）=12.0%, reaction temperature 145 ℃, and reaction time 2 h. The esterification efficiency of lactic acid was about 96.6%.

气相色谱-质谱联用技术测定乳制品中反式脂肪酸

对超市中常见的几种乳制品中的脂肪酸进行了提取和检测,采用酸酯化、碱酯化、碱皂化酸酯化三种前处理方式并进行效果比较,进而选取碱皂化酸酯化法,运用气质联用仪对八种乳制品进行测定,得出大部分乳制品中含有反式脂肪酸的结论,以期为乳制品的品质鉴定提供依据。

Synthesis and characterization ofα-butyl-ω-{3-[(2,2-dihydroxymethyl)-propionyloxy]}propylpolydimethylsiloxanes

A series of polydimethylsiloxanes containing two primary hydroxyl groups at one single chain end were synthesized by five-step reactions which included esterification, hydroxyl protection, anionic ring-opening polymerization, hydrosilylation and deprotection. The prepared compounds in each step were characterized. The results showed that each step synthesis was successfully carded out and objective products could be achieved.

Pig Liver Esterase-catalyzed Hydrolysis of Three Diesters of meso-Bicyclic Dicarboxylic Acid and Three Tetraesters of Tetrahydrofuran -2,3,4,5-tetracarboxylic Acid

Three diesters of exo- syn-meso-oxabicyclo (2, 2, 1 ) -hept- 5- ene- 2, 3- dicarboxylic acid and three tetraesters of tetrahydrofuran-2, 3, 4, 5-tetracarboxylic acid were synthesized and tested with enantioselective hydrolysis catalyzed by pig liver esterase(PLE). The results of the PLEcatalyzed hydrolysis were discussed.

海洋贝壳基固体碱催化合成甲基丙烯酸叔丁酯

通过煅烧法制备了8种海洋贝壳基固体碱,并用于催化合成甲基丙烯酸叔丁酯(t-BMA)。经活性比较,优选出催化合成t-BMA的最佳固体碱为牡蛎贝壳基固体碱Ⅱ(OSBⅡ),其对应的t-BMA收率高达49.77%。考察了二次煅烧温度对OSBⅡ催化剂表面碱性的影响,得到优化的二次煅烧温度为700℃,对应表面碱密度为0.281 mmol/g。采用扫描电镜、N_(2)吸附-脱附、红外光谱等方法初步探究OSBⅡ的可能构效关系,结果表明OSBⅡ催化剂因含有大量的表面碱性活性位点而呈现出较强的催化活性。

Water-Promoted Kinetic Separation of trans- and cis-Limonene Oxides

The efficient hydrolytic kinetic separation of trans/cis-（R）-（＋）-limonene oxides was realized in a 1 ： 1 mixed solvent of water and 1,4-dioxane without additional catalyst. Optically pure trans-（R）-（＋）-limonene oxide was recovered in high yield （77%）.

碳酸二甲酯与乙醇酯交换反应动力学

在间歇反应釜内,以甲醇钠为催化剂,对碳酸二甲酯与乙醇酯交换合成碳酸二乙酯反应进行了研究,考察了催化剂浓度、反应温度、乙醇与碳酸二甲酯的摩尔配比等因素对酯交换反应的影响,通过数据校正优化了实验原始数据,建立了动力学模型并进行严格的模型检验,得到了可靠的模型参数。结果表明,该反应为连串反应,中间产物为碳酸甲乙酯,反应焓分别为ΔH10=-1.595 kJ?mol-1,ΔH20=0.809 kJ?mol-1;两个反应均为可逆反应,活化能分别为Ea1+=45.633 kJ?mol-1和Ea1-=47.228 kJ?mol-1、Ea2+=55.058 kJ?mol-1和Ea2-=54.249 kJ?mol-1。

酶法制备甘油二酯与甘油三酯的结晶特性研究

采用Lipozyme RM IM催化大豆油和棕榈油硬脂(熔点45℃)混合油与单甘酯(由大豆油、棕榈油硬脂和甘油合成)酯交换合成甘油二酯,并以此酶催化大豆油和棕榈油硬脂(熔点45℃)酯交换合成甘油三酯。采用差示扫描量热仪、脉冲核磁共振仪和偏光显微镜测定甘油二酯、甘油三酯以及甘油三酯中添加不同比例甘油二酯(10%、30%、50%和70%)的混合物的结晶和熔化性质。结果表明:脂肪酸组成接近的甘油二酯,初始结晶温度(28.14℃)和熔点(48.26℃)比甘油三酯初始结晶温度(8.51℃)和熔点(30.58℃)高。添加50%和70%的甘油二酯能够提高甘油三酯的熔点和初始结晶温度,而添加10%和30%的甘油二酯对其结晶影响较小。随着甘油二酯添加比例的增大,混合物的固体脂肪含量逐渐增加。添加50%和70%甘油二酯的混合物,在熔点温度附近时晶体为针状。

桐油制备生物柴油的工艺研究

以四川桐油为原料,研究了生产生物柴油过程中的酯交换反应条件的影响。结果表明,当甲醇和油脂的物质的量之比超过6∶1后,桐油转化率提高范围很小。当油脂中含有少量游离脂肪酸和水分时,通过甘油虽可测定油脂的转化率,但是后处理时乳化严重,甲酯的损失较大从而影响甲酯的收率。反应温度对反应的转化率影响较大。通过测定桐油生物柴油的物性,表明桐油生物柴油的低温流动性良好,可以作为低温流动性改进剂与其它油脂制备的生物柴油混合使用。闪点为194℃,硫含量为70.75μg/g。

固定化脂肪酶催化菜籽油合成蜡酯

以菜籽油、鲸蜡醇为原料,采用实验室自制的固定化Candidia sp.99-125脂肪酶分别在有机溶剂和无溶剂体系下合成了蜡酯,在两种体系下对影响蜡酯合成的各种因素进行了比较研究,研究表明:以正己烷为反应介质,在40℃条件下反应12h,油醇摩尔比1∶2,酶量15%(质量分数,上同),水含量7.5%,蜡酯产率可达85.87%;无溶剂体系中在50℃条件下反应20h,油醇摩尔比1∶1.5,蜡酯产率可达80.68%。通过流加鲸蜡醇可以提高酶的使用寿命。

强碱催化棉籽油酯交换制备生物柴油的动力学

Methyl esters were produced by trans-esterification of c ottonseed oil with methanol in the presence of a homogeneous catalyst (KOH).A ki netic model was established by taking three consecutive and reversible reactions into consideration.Rate constants were determined for each reaction by the Rung e-Kutta method with optimization.The corresponding values of frequency factor a nd activation energy were then obtained based on the Arrhenius’ law for a ll forward and reverse reactions under different experimental conditions.

鸡油制备生物柴油的研究

采用鸡油在催化剂KOH的作用下与甲醇发生酯交换反应制备生物柴油,研究了醇油摩尔比、催化剂用量、反应时间、反应温度对反应产率的影响。实验结果表明:醇油摩尔比为7∶1、KOH质量分数为1.0%、反应时间为50min、反应温度为60℃为最优操作条件。在此条件下生物柴油的收率可达97.0%。制得的生物柴油与我国0#柴油和德国生物柴油的主要性能指标接近。

酯交换法制备乙酸正丁酯动力学研究

为了给乙酸正丁酯的工业生产提供动力学支持,文章在间歇搅拌釜式反应器中利用酯交换法将乙酸甲酯转化为乙酸正丁酯。首先筛选出Si-3为最优催化剂,然后考察了转速、反应温度、催化剂用量、醇酯比等因素对反应过程的影响,确定较优的实验条件为转速400 r/min,反应温度70℃,催化剂用量(质量分数)20%,醇酯比(摩尔比)为1.25∶1。在323—343 K下,将实验数据拟合后得到酯交换反应的动力学方程。正反应速率常数为6 291.15 L/(mol·s),正反应活化能50 134.7 J/mol;逆反应速率常数为137.72 L/(mol·s),逆反应活化能38 324 J/mol。通过实验与计算值的比较验证,此宏观动力学方程合理,可用于模拟计算。

桐油转化生物柴油工艺技术分析与研究

[目的]研究以桐油为原料,利用酯交换法转化生物柴油的工艺技术,为桐油作为生物柴油原料油的应用提供参考。[方法]通过单因素试验和正交试验,对影响生物柴油产量的主要因素进行了分析。[结果]试验表明,影响桐油转化生物柴油的主要因素有催化剂用量、甲醇用量、反应温度、反应时间及原料油中的含水量。其中甲醇用量对桐油酯交换反应转化生物柴油的影响最大,其次为反应时间,再次为催化剂用量和反应温度。综合分析得到最优的反应条件为甲醇用量约占桐油重的50%、催化剂NaOH占桐油重的1.00%、反应温度50～65℃、反应时间30～40min,转换率超过80%。[结论]利用酯交换反应,以桐油转化生物柴油是可行的,最佳工艺条件下制备的桐油生物柴油的主要性能指标基本符合石化柴油标准。

酸离子液体在生物柴油酯交换反应中的催化活性

合成四类不同含氮官能团及不同阴离子的Brфnsted酸离子液体,用核磁共振(NMR)、红外光谱(IR)、热重分析(TG/DTA)等表征方法对其进行表征.在此基础上,研究三油酸甘油酯和甲醇的酯交换反应,考查离子液体种类对酯交换反应的催化能力.结果表明:离子液体催化剂的活性与其含氮官能团结构和阴离子酸强度以及酸量有关.通过阴阳离子共同作用,将阴离子为HSO4-和H2PO4-的吡啶类和甲基吡啶类离子液体结合使用,既能使反应快速进行又可以得到较高的甲酯收率.

酶催化合成混合型蔗糖酯的研究

在有机溶剂中,以脂肪酶Novo435为催化剂,使蔗糖八乙酸酯与油酸乙酯进行酯交换反应合成了同时含有油酰基和乙酰基的混合型蔗糖酯,当蔗糖八乙酸酯/油酸乙酯(摩尔比)=1:1时,油酸乙酯的转化率达95%。通过正交实验得到的适宜反应条件为:以叔戊醇为反应介质,反应温度40℃,以0.1mmol蔗糖酯计,脂肪酶用量20-60mg,分子筛用量20mg。