聚酯(PET)反应过程研究⒇Ⅳ酯化反应过程数学模拟

通过对酯化反应器流动模型的分析结合酯化反应化学平衡、反应动力学和反应器内传质的研究建立了适用于多种工业酯化反应器的数学模型     

聚酯（PET）反应过程研究：Ⅳ酯化反应过程数学模拟

通过对酯化反应器流动模型的分析结合酯化反应化学平衡，反应动力学和反应器内传质的研究建立了适用于多种工业酯化反应器的数学模型。     

酯化反应耦联渗透汽化膜过程对平衡移动的影响

以乙酸正丁酯的合成为目标反应,系统地考察了渗透汽化－ 酯化反应耦联复合膜反应器中过程因素（进料中醇、酸摩尔比率、膜面积与反应混合物体积的比值、复合膜渗透通量的大小,反应、分离温度等）对酯化反应化学平衡移动的影响。实验发现反应（分离）温度是影响酯化反应化学平衡移动的最重要因素。     

催化剂对酯化反应渗透汽化膜稳定性的影响

比较了酯化反应耦合渗透汽化膜反应器中不同的催化剂体系及其含量对ＰＰＶＡ／ＰＡＮ复合膜稳定性的影响。试验结果表明,固体超强酸催化剂体系对复合膜的稳定性没有影响。活性层酯化度为３．３％及６．２％的复合膜具有良好的稳定性。能够适合于酯化反应耦合渗透汽化过程研究及应用。     

微通道反应器中油酸与低级醇的酯化反应研究

本研究以高酸值油酸为原料,采用微通道反应器与0.38*12mm毛细管相连接,建立了快速酸催化制备生物柴油的微结构反应器。进行了油酸酯化反应,寻找合适的反应条件。考察了停留时间、醇酸摩尔比、催化剂浓度、反应温度对酯化反应的影响。在78℃条件下,油酸与低级醇反应停留时间仅为10 min,产率可达80%以上;与传统釜式反应器相比,微反应器减少了催化剂用量,缩短了反应时间,提高了反应过程中的安全性。此外,建立了均相动力学模型。确定了生物柴油的酯化反应的速率常数和活化参数。     

莰烯乙酸酯化制乙酸异龙脑酯宏观动力学

采用φ3 mm×3 mm条状工业分子筛催化剂,在固定床管式反应器中考察了该催化剂在崁烯酯化制备乙酸异龙脑酯中的反应性能,建立了幂函数宏观动力学模型,运用最小二乘法进行动力学模型参数估计。结果表明,崁烯酯化制备乙酸异龙脑酯的表观活化能(Ea)为47.225 k J/mol,对崁烯和乙酸的反应级数分别为0.15和0.5。预测值与实验值能较好地吻合,表明动力学模型是适用的。     

五釜工艺聚酯工业装置的稳态模拟

针对大型连续PTA直接酯化法PET工艺过程装置,以Aspen Plus和Polymers Plus为模型开发工具,建立了以反应和传质过程机理为基础的稳态模型。结果表明:该模型中包括了酯化反应、缩聚反应、二甘醇生成反应、链降解反应和乙醛生成等主副反应,且考虑了端羧基对酯化反应的自催化效应;更重要的是模型考虑了酯化阶段PTA在酯化反应器中的溶解过程和终缩聚阶段小分子的脱挥,并建立了小分子脱挥的传质系数与缩聚反应器内聚合度、黏度、温度和搅拌器转速等的关联;在此模型基础上模拟研究了第一酯化反应操作温度对各反应器出口指标的影响,指出酯化段的酯化率有一个适宜的控制范围。     

丙烯酸与异丁烯酯化合成丙烯酸叔丁酯动力学

为实现丙烯酸与异丁烯酯化合成丙烯酸叔丁酯的工业化,在间歇釜式反应器内,研究了磺酸改性SBA-15介孔分子筛催化丙烯酸与异丁烯加成酯化合成丙烯酸叔丁酯的本征反应动力学。结果表明,在搅拌转速大于400 r/min,催化剂粒径为0.15~0.18 mm,可消除内、外扩散影响。测定了酸烯酯化合成丙烯酸叔丁酯的本征反应动力学数据,建立了幂级数反应动力学方程,采用非线性最小二乘法拟合得到模型参数,得到酯化反应的正逆反应活化能分别为33.8和61.7 k J/mol,异丁烯二聚反应的正逆反应活化能分别为42.7和91.6 k J/mol,实验测定值与模型计算值吻合较好。     

双环戊二烯解聚制环戊二烯的工程开发研究

对双环戊二烯解聚制环戊二烯的反应过程进行了热力学与动力学分析 ,建立了解聚反应器的数学模型 ,包括反应动力学模型与传递过程模型。在中试装置上对反应动力学模型进行了检验 ,模拟计算结果与中试反应器实际反应结果符合较好     

微尺度下渗透汽化?酯化反应耦合过程

设计加工了新型膜微反应器,分析了该设备对渗透汽化?反应耦合过程的强化作用.以酯化反应为模型反应,在催化膜微反应器中,考察了有无渗透汽化作用下催化剂负载量和温度对酯化反应性能的影响.结果表明,在反应停留时间60 min、温度65℃的条件下引入渗透汽化作用,转化率由13.6%提高至54.0%.由于微反应系统的比表面积大且扩散距离短,过程微型化有利于副产物水的脱除,能强化膜分离与反应耦合过程.在催化剂含量15%(?)、反应停留时间60 min、温度65℃的条件下,催化膜微反应器和常规尺寸催化膜反应器内的酯化反应转化率分别为54.0%和29.3%.微反应设备中无需机械搅拌,对催化膜有保护作用.     

Production and Isolation of n‐Butyl Acrylate Using Pervaporation‐Aided Esterification Reaction: Kinetics and Optimization

Synthesis of n‐butyl acrylate by esterification of acrylic acid with n‐butyl alcohol was carried out in a batch membrane reactor. Optimization and design of the experiment was accomplished by response surface methodology with Box‐Behnken experimental design. The effects of different parameters like reaction temperature, catalyst concentration, molar ratio of alcohol to acid, and ratio of membrane surface to initial volume on water flux and conversion of acrylic acid were evaluated. A kinetic model for the esterification‐coupled pervaporation process was developed. Kinetic parameters were estimated by a nonlinear optimization technique in the MATLAB optimization toolbox. The experimental and simulation results were applied for developing a concept to effectively conduct a pilot‐scale esterification‐pervaporation experiment.     

Esterification of Acetic Acid and Ethanol in a Flow‐Through Membrane Reactor Coupled with Pervaporation

The esterification of acetic acid is an important industrial process for the synthesis of ethyl acetate. A membrane reactor with a sulfonated polyethersulfone/polyethersulfone/non‐woven fabrics composite catalytic coupled with a poly(vinyl alcohol) pervaporation membrane was applied in continuous esterification of ethanol with acetic acid in a flow‐through mode. High equilibrium conversion was obtained for esterification in a closed‐loop mode. For the pervaporation‐assisted esterification in this mode, the experimental conversion was very close to the theoretical value.     

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。     

Preparation of zeolite-coated pervaporation membranes for the integration of reaction and separation

Pervaporation is a promising option to enhance conversion of reversible condensation reactions, generating water as a by-product. In this work, composite catalytic membranes for pervaporation-assisted esterification processes are prepared. Catalytic zeolite H-USY layers have been deposited on silica membranes by dip-coating using TEOS and Ludox AS-40 as binder material. Membrane pre-treatment and the addition of binder to the dip-coat suspension appear to be crucial in the process. Tuning of catalytic layer thickness is possible by varying the number of dip-coat steps. This procedure avoids failure of the coating due to the high stresses, which can occur in thicker coatings during firing. In the pervaporation-assisted esterification reaction the H-USY coated catalytic pervaporation membrane was able to couple catalytic activity and water removal. The catalytic activity is comparable to the activity of the bulk zeolite catalyst. The collected permeate consists mainly of water and the loss of acid, alcohol and ester through the membrane is negligible. The performance of the membrane reactor is mainly limited by reaction kinetics and can be improved by using a more active catalyst.     

Membrane reactors in chemical production processes and the application to the pervaporation-assisted esterification

When appropriate membrane was used for the assistance of chemical and biochemical equilibrium reactions, it is possible to enhance the yield and the purity of the reaction product by selectively adding educts or selectively removing products and to a lower the energy input and the reaction time compared to conventional process. In this paper a review on membrane reactors with special emphasis on membrane-assistance of esterification reactions and a continuous tube membrane reactor for the pervaporation-assistance of the esterification are presented. The heterogeneously catalyzed esterification of ethanol and acetic acid to ethyl acetate and water was investigated as a typical chemical equilibrium reaction. The selective and simultaneous water separation from the reaction mixture of the esterification with polyvinyl alcohol pervaporation membranes is considered to be an interesting process alternative to the conventional distillation process. Compared to the distillation process, for the pervaporation-assisted process a decrease of the energy input of over 75% and of the investment and operating coasts of over 50% each was calculated.     

Pervaporation membrane reactor study for the esterification of acetic acid and isobutanol using polydimethylsiloxane membrane

In this study, isobutyl acetate, a valuable solvent in cosmetics, aroma and paint industries, is produced by pervaporation–esterification equilibrium reaction in a batch pervaporation membrane reactor (PVMR) using homogeneous (sulphuric acid) and heterogeneous (Dowex 50W-X8) catalysts. The effects of catalyst loading, catalyst type, reaction time, membrane thickness, temperature and initial molar ratio of reactants were investigated. A cross-linked polydimethylsiloxane (PDMS) membrane selective to esters was prepared and used in PVMR. Batch reactions were carried out also in a simple batch reactor (SBR) without pervaporation under the same conditions to compare the conversions for the reactions with and without pervaporation. In conclusion, PVMR experiments showed that the PDMS membrane can be used to remove the isobutyl acetate formed selectively with acceptable conversions and pervaporation fluxes.     

Pervaporation‐Assisted Esterification of Caproic Acid with Isobutanol in Conventional,In Situ,and Ex Situ Reactors

The factors that affect the pervaporation‐assisted esterification of caproic acid and isobutanol have been investigated in a batch reactor and compared with two different pervaporation reactors, in situ and ex situ reactors, with different configurations. The operating process parameters of the pervaporation modules can be adjusted to optimize the performance, which improves the conversion of reactants and reduces the operating costs. The performances of the reactors have been extensively studied and the membrane selectivity has been investigated in terms of the flux of individual reaction species. The mass transfer limitation of both pervaporation reactors was studied and suitably eliminated. In addition, the performance of the pervaporation reactors was investigated by evaluating the ratio of water removal rate to the water production rate.     

醋酸丁酯酯化反应体系组分在PEBA膜中的吸附性能

采用实验和模型计算两种方法研究了醋酸丁酯酯化反应体系组分在涂布法制备的用于渗透汽化分离的PEBA膜材料中的吸附行为.分别用Flory-Huggins和ONIQUAC模型预测了全浓度范围内的水/有机物二元混合液在PEBA膜中的吸附量.用溶解度参数法得到Flory-Huggins模型中的相互作用参数;用纯溶剂与膜的平衡吸附数据拟合得到UNIOUAC模型中溶剂与膜的二元相互作用参数,而溶剂之间的二元相互作用参数可用文献中汽液平衡数据关联拟合.结果表明PEBA膜材料的亲有机物性能良好,对于四种组分的选择吸附性顺序为:醋酸正丁酯>正丁醇>醋酸>水,并且两种模型的计算结果基本一致.