乙酸与丁醇酯化反应和渗透蒸发耦合过程研究

以硫酸锆催化乙酸和丁醇的酯化反应为例对渗透蒸发和酯化反应耦合过程进行研究 ,考察了温度、反应物初始摩尔比、膜面积与反应液体积比和催化剂浓度对耦合过程的影响。     

氨基磺酸催化乙酸酯化反应的研究

采用氨基磺酸作催化剂,对乙酸正丁酯合成反应进行了探索性研究。讨论了影响产率的多种因素。最佳条件下乙酸正丁酯产率可达到８８．２％。对其它乙酸酯类物质也进行了合成试验,获得了满意的结果。     

我国固体酸催化合成酯的研究

综述了近年来我国固体酸催化合成酯的研究进展。     

Aluminum Containing MCF Silica as Highly Efficient Solid Acid Catalyst for Alcohol Esterification

Aluminum incorporated mesocellulous silica foams (Al-MCF) with various Si/Al ratios have been hydrothermally synthesized. The characterization results indicate that the characteristic mesocellular structural features of MCF are preserved after the aluminum incorporation. The catalysts exhibit highly catalytic performance in the esterification of acetic acid with amyl alcohol in the liquid phase.     

乙酸与甲醇的催化酯化

Esterification of methyl alcohol with acetic acid catalysed by Amberlyst-15 (cation-exchange resin) was carried out in a batch reactor in the temperature ranging between 318-338 K, at atmospheric pressure. The reaction rate increased with increase in catalyst concentration and reaction temperature, but decreased with an increase in water concentration. Stirrer speed had virtually no effect on the rate under the experimental conditions. The rate data were correlated with a second-order kinetic model based on homogeneous reaction. The apparent activation energy was found to be 22.9kJmol-1 for the formation of methyl acetate. The methyl acetate production was carried out as batch and continuous in a packed bed reactive distillation column with high purity methyl acetate produced.     

乙酸与正丁醇催化精馏过程模拟

用平衡级与拟均相非平衡级模型对乙酸和正丁醇催化精馏过程进行了数学模拟，结果表明，2种模型所得结果与实验值吻合较好，计算所得的汽液相浓度和汽液相流速沿塔高的分布规律与实验结果一致。     

Preparation of Keggin and Preyssler Heteropolyacid Catalysts on Amine-modified SBA-15 and Their Catalytic Performances in Esterification of n-Butanol with Acetic Acid

The Keggin and Preyssler-structured tungstophosphoric acid catalysts anchored on the surface of modified SBA-15 (KNS and PNS) by grafting amine groups into system, and were characterized by infra-red spectroscopy, X-ray diffraction, N₂-adsorption, Hammett indicator and UV-Vis spectroscopy. Their catalytic behaviors were investigated in the esterification of n-butanol with acetic acid. Characterization results for obtained catalysts verified the ordered hexagonal mesostructure of SBA-15 and preservation of the structures of heteropolyanions on amine-modified SBA-15. KNS and PNS catalysts with the 37 and 25% loadings of Keggin and Preyssler acids exhibited considerable conversions of n-butanol of 61.2 and 63.8% with both 100% selectivity for n-butyl acetate in the esterification reaction, respectively. Especially, tests of six-cycle reaction revealed good reusabilities of KNS and PNS due to their excellent water-resistance properties, and in contrast, the catalysts prepared by direct impregnation lost their high activities immediately at their second cycles. Active sites on the amine-modified SBA-15 retained the Keggin or Preyssler structure after reaction demonstrated by IR analysis. Also, reaction conditions such as the amount of catalyst, reaction time and temperature were explored.     

硫酸氢钠催化合成乙酸乙酯动力学

研究了以硫酸氢钠为催化剂,乙酸与乙醇直接酯化合成乙酸乙酯的反应动力学。在不同条件下测量了反应物浓度随时间的变化关系,计算得到硫酸氢钠催化下的酯化反应速率常数。实验结果表明,硫酸氢钠催化合成乙酸乙酯的反应为二级可逆反应。在实验温度(60~90℃)和催化剂浓度(0.3%~2%)质量分率的条件下,反应速率常数与温度及催化剂浓度的关系可表为Arrhenius方程形式的函数,反应活化能为45.28 kJ/mol,指前因子则与催化剂的浓度有关。     

异丁烯与醋酸酯化合成醋酸叔丁酯

以锆复合氧化物和大孔强酸性阳离子交换树脂为催化剂,催化异丁烯与醋酸合成了醋酸叔丁酯。采用正丁胺电位滴定法对催化剂的酸强度和酸量进行了表征。结果表明:对异丁烯与醋酸酯化反应而言,随着酸量增加,转化率增大,但酸强度增大会导致选择性下降。以异丁烯质量分数为10%的混合烃为原料,D008为催化剂,异丁烯单程转化率可达80%,醋酸叔丁酯的选择性为95.98%。     

磷钨酸催化合成癸二酸二乙酯的研究

磷钨酸作为癸二酸和乙醇的酯化催化剂,性能优于硫酸。经实验确定了最佳反应条件为醇、酸物质的量比为４－０∶１ ,磷钨酸用量是酸质量的４ ％ ,反应时间４ ｈ ,酯化率达９６－８５ ％ ,选择性９９－８ ％ ,产品纯度达９８ ％ 以上,并且催化剂可以重复使用多次。     

Preparation and Characterization of a Magnetic Solid Acid for Esterification of Ammonium Lactate with n-Butanol

One kind of magnetic solid acid (MSA) was prepared by thermolysis of nickel sulfate with ferric hydroxide at 1,123 K. Its properties, such as magnetism and surface acidity, were investigated by PPMS, FTIR-NH₃, TPD-NH₃, XRF, XRD techniques. Its saturation magnetization is estimated to be 10.72 emu/g and a hysteretic feature with a remnant magnetization (2.76 emu/g) and coercivity (0.15 kOe) at 300 K is exhibited. The results also reveal that MSA solely possesses mild Lewis acid sites and four crystalline phases. Its catalytic activity for esterification of ammonium lactate with n-butanol was tested. The esterification yield (Ey) will be significantly enhanced when SnCl₂ · 2H₂O is added. The highest Ey will be up to 87.3% when the complex concentration is 5 wt% (mass ratio of SnCl₂ · 2H₂O to MSA = 4:1). The possible reasons correlating with the esterification performance of the complex system are discussed.     

用于酯化反应的堇青石担载固体酸催化剂的制备工艺探索

以堇青石为载体担载固体酸催化剂活性组分,以乙酸与乙醇合成乙酸乙酯的反应为模型反应,考察多种制备条件对堇青石担载固体酸催化剂酯化活性的影响,筛选最佳制备工艺. 结果表明,固体酸颗粒悬浊液性质均一、稳定,浸渍液中添加g-Al2O3或聚乙二醇会阻碍催化剂表面活性的发挥. 以悬浊液为浸渍液,1 mol/L H2SO4溶液达50%(j)的工艺条件下,堇青石担载固体酸催化剂酯化活性最高. 堇青石表面担载的固体酸是酯化活性中心,全回流反应100 min,乙酸的转化率达到79.2%,二次利用时转化率为一次转化率的95.6%. 堇青石担载固体酸催化剂制备工艺的平行性和稳定性较好,催化剂外形规整,孔道均匀整齐,在保持高活性的同时,达到催化剂成型和提高酯化催化剂经济性的目的.     

离子交换树脂催化柠檬酸与正丁醇酯化反应动力学研究

在间歇搅拌反应器中,研究强酸性离子交换树脂D072型催化柠檬酸与正丁醇酯化合成柠檬酸三丁酯的反应动力学。在消除内外扩散的条件下,测定了不同催化剂用量和不同反应温度条件下反应体系中柠檬酸浓度随反应时间的变化,按拟均相可逆反应,并采用初始反应速率法求取反应动力学方程参数。在催化剂与柠檬酸的质量比为0.02~0.06,反应温度为373.15~423.15 K时,得到反应动力学模型的指前因子为1.250 3L~3·mol~(-3)·min~(-1),反应活化能为11 732.58J/mol。在实验范围内对获得的反应动力学模型进行验证,计算值与实验值吻合较好。     

醋酸制备乙醇用催化剂研究

综述了国内外醋酸制备乙醇催化剂的研究现状、技术特点、反应机理及最新进展,指出了醋酸制备乙醇催化剂的研究方向。     

超稳Y沸石负载磷钨酸催化合成环己烯

以超稳Y沸石负载磷钨酸作为催化剂,对环己醇脱水制备环己烯的反应进行了研究,考察了影响反应的各种因素。结果表明,最佳的反应条件为:沸石粒度筛孔0.075～0.080mm,催化剂中磷钨酸的质量为环己醇总质量的3.6%～4.3%,反应温度为180～190℃。在此条件下,环己烯的收率在91.5%～93.9%,催化剂可以重复使用3次。     

Synthesis and Characterization of Nano Silica Supported Tungstophosphoric Acid: An Efficient, Reusable Heterogeneous Catalyst for the Synthesis of Azlactones

A rapid and scale up protocol for the synthesis of azlactones by the Erlenmeyer method under solvent-free conditions was developed. Tungstophosphoric acid supported on nano-silica, TPA@nano-SiO₂ was used as a heterogeneous catalyst for the synthesis of a wide range of azlactone derivatives. The catalyst was characterized by physicochemical measurements. The procedure was simple and permitted the quantitative isolation of products and catalyst under thermal conditions. The recycled catalyst was reused more than 5-times without loss of catalytic activity.     

Fast Esterification of Acetic Acid with Short Chain Alcohols in Microchannel Reactor

Microchannel reactor was used for the fast synthesis of acetic acid esters, including methyl acetate, ethyl acetate, n-propyl acetate and n-butyl acetate. Effects of the inner diameter of microchannel reactors, dosage of catalyst, residence time, reaction temperature and molar ratio of alcohol to acetic acid on yields of esters were studied in the p-toluene sulfonic acid-catalyzed homogeneous esterification of acetic acid with alcohols. Yields of acetic acid ester reached 74.0, 70.1, 97.2 and 92.2% when methanol, ethanol, n-propanol and n-butanol were used as the alcohols, respectively and the residence time was of 14.7 min.     

离子交换树脂催化乳酸与异丁醇及正丁醇酯化反应的动力学研究

The esterification reactions of lactic acid with isobutanol and n-butanol have been studied in the presence of acid ion-exchange resin Weblyst D009. The influences of catalyst loading, stirrer speed, catalyst particle size, initial reactant molar ratio and temperature on the reaction rate have been examined. Experimental kinetic data were correlated by using the Pseudo-homogeneous, Langmuir-Hinshelwood and Eley-Rideal models. Nonideality of the liquid phase was taken into account by using activities instead of molar fractions. The activity coefficients were calculated according to the group contribution method UNIFAC. Provided that the nonideality of the liquid is taken into account, the esterification kinetics of lactic acid with isobutanol and n-butanol catalyzed by the acid ion-exchange resin can be described using all three models with reasonable errors.