丙烯水合反应器数学模型

<正>1 引言 异丙醇是一种重要的有机化工原料,目前工业生产多用丙烯气相直接水合法。对该类异丙醇生产装置的建模与操作条件的优化国内外未见文献报道。本文针对某化工厂的工业丙烯气相直接水合反应器装置,从反应动力学机理出发,结合生产数据,建立了该反应器的简化数学模型,为该反应器的操作条件在线优化提供了依据。2 数学模型的建立     

Pervaporation separation of water–isopropanol mixture using carboxymethylated poly(vinyl alcohol) composite membranes

The pervaporation separation of water–isopropanol mixtures was carried out using carboxymethylated poly(vinyl alcohol) (CMPVA) composite membranes. Carboxymethylated PVA (CMPVA) was synthesized by reacting PVA with various concentrations of monochloroacetic acid. Substitution efficiency of the CMPVA ranged from 12–32%. The cross‐sectional structure of the composite membrane for pervaporation was confirmed by scanning electron microscopy (SEM) exhibiting a 20‐μm active skin layer. Glass transition temperature of the CMPVA was in the range of 74–84°C, and decreased with increasing substitution efficiency. Degree of swelling and permeation flux for water–isopropanol in pervaporation increased with the substitution degree of carboxymethylation. CMPVA composite membrane, having 16% substitution efficiency, showed the following pervaporation performance; permeation flux of 831 g/m² h and separation factor of 362 measured at 80°C and 85 wt % feed isopropanol concentration. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 241–249, 1999     

从异丙醇废液中回收高浓度异丙醇装置的可行性研究

简述了异丙醇的用途和市场概况,介绍了设计的间歇法生产装置,通过技术经济分析表明,该工艺具有较好的经济效益和社会效益.     

亲水性沸石膜在异丙醇脱水中的应用及其耐酸性研究

采用二次生长法,在α-Al2O3陶瓷管上制备亲水性NaA、T型、ZSM-5沸石膜,采用SEM对其进行表征.比较3种亲水性膜在异丙醇/水体系的渗透汽化性能,考察其在不同的料液温度下对异丙醇的分离效果.通过优化膜合成液中Si/Al和F-/Si的摩尔比、合成时间等条件,提高ZSM-5沸石膜的渗透汽化性能.分析考察膜的耐酸性能,结果显示ZSM-5沸石膜具有良好的耐酸性;将ZSM-5沸石膜在pH为5.8的酸性溶液浸泡10天后,用于97%的乙酸乙酯/水体系中渗透汽化脱水,渗透液水含量可达99.59%,渗透通量可达0.12kg/(m2·h),分离因数高达7 894.     

异丙醇水溶液尿素脱蜡装置节能改造

国内的异丙醇水溶液尿素脱蜡装置与同类工艺相比有一定优势 ,但在装置能耗方面与分子筛脱蜡技术有一定差距 ,因此对原有装置中用能较多的异丙醇回收系统进行改造很有必要。介绍了异丙醇水溶液尿素脱蜡装置节能改造过程和应用效果     

丙酮的生产与发展

本文介绍了丙酮的生产方法和发展，对国内丙酮生产状况作了评述。     

正己烷–异丙醇共沸体系液液相平衡数据测定及关联

为了给溶剂萃取分离正己烷–异丙醇混合物的过程设计和流程模拟计算提供基础数据，以二甲亚砜、1,4-丁二醇、1,2-丙二醇、乙腈、糠醛和N,N-二甲基甲酰胺为萃取剂，测定了30℃下萃取分离正己烷–异丙醇混合物的液液相平衡数据，并利用分离因子评价不同萃取剂的萃取分离性能。根据Hand方程对实验数据进行一致性和可靠性检验，拟合方程的相关系数都在0.98以上。随后，采用Aspen Plus软件选取NRTL活度系数模型对相平衡数据进行关联，得到相应的二元交互作用参数，并以此计算相应的相平衡组成。结果显示，计算值和实验值的均方根偏差小于1.0%，表明NRTL模型能够准确描述三元体系的液液相平衡。     

ZIF-8 membrane synthesized via covalent-assisted seeding on polyimide substrate for pervaporation dehydration

In this study, a novel covalent-assisted seeding method is developed to fabricate well-intergrown ZIF-8 membrane on polyimide (PI) substrate with imidazole-2-carboxaldehyde (ICA) as the covalent agent between ZIF-8 layer and PI substrate. Compared to ethylenediamine-crosslinked PI membrane and ZIF-8/PI membrane synthesized without covalent-assisted seeding method, ZIF-8/PI membrane synthesized with ICA covalent-assisted seeding method shows improved pervaporation performance for isopropanol dehydration. Subsequent surface coating with polydimethylsiloxane or polydopamine is applied to mitigate the grain boundary of ZIF-8/PI membrane, which results in a further performance enhancement. The morphologies and physicochemical properties of the resultant membranes are characterized by scanning electron microscope, attenuated total reflectance-Fourier transform infrared, X-ray diffraction, and water contact angle. The effect of operation temperature on the separation performance is also carried out. This work demonstrates the novel covalent-assisted seeding method for the preparation of ZIF-8 membrane with high-performance, which may hold a great potential for various ZIF membranes separation applications.     

A comparative study on the electrochemical properties of ring‐substituted polyanilines

The redox behavior of polyanilines with ring‐substituted groups synthesized by chemical polymerization, poly‐2,5‐dimethoxyaniline (PDMAn), poly‐m‐chloroaniline (PmClAn) and poly‐o‐toluidine (POT), was studied and the morphology and crystal orientation of platinum particles deposited on these polymer membranes was compared. The oxidation of isopropanol on platinized polyaniline‐modified electrodes as a model reaction was also investigated to examine the electrocatalytic properties of the polymers. The results show that the first oxidation potential of the polymers increases in the following sequence: PDMAn, POT and then PmClAn, which can be explained in terms of the electronic and steric effects of ring‐substituted groups. The growth of Pt particles electrodeposited on doping‐state POT and PDMAn polymer membranes takes place by a ‘progressive nucleation mechanism’, but by an ‘instantaneous nucleation mechanism’ on PmClAn. Platinum crystallites trend towards preferred‐orientation and Pt (200) is the preferred face, but the degree of preferred orientation depends on the polymer. The oxidation potentials of isopropanol are located near 0.3 V, and the oxidation currents increase on platinized polymer‐modified electrodes, indicating that the interaction of polymer with Pt particles might improve the catalytic activity of Pt. Polyanilines act not only as dispersion media but also change the electronic properties of Pt crystalline grains. Copyright © 2005 Society of Chemical Industry     

改性Beta（Na）型分子筛对异丙醇苯酚烷基化反应的影响

本文研究了用Beta（Na）型分子筛及用Na2O、磷钨酸改性后的Beta（Na）型分子筛作催化剂对苯酚异丙醇烷基化反应的影响。采用NH3-TPD、X射线衍射对催化剂晶相和表面酸性进行表征。实验结果表明：用Na2O改性后催化剂基本失活,而用磷钨酸改性后转化率可达68.3165%,邻异丙基苯酚选择性可达59.9167%。