膜反应器中5A分子筛负载氢氧化钾催化合成乙二醇单乙醚

以环氧乙烷和无水乙醇为原料,以负载KOH的5A分子筛为催化剂,在连续操作的膜反应器中合成乙二醇单乙醚.考察了反应温度、KOH负载量及空时对乙醇转化率和乙二醇单乙醚选择性的影响.结果表明,以KOH负载质量分数为17.6%的5A分子筛作为催化剂,在110 ℃和空时2 h的条件下反应,乙二醇单乙醚的选择性达到了88.81%.通过膜反应器与间歇釜式反应器对比实验发现,膜反应器中乙二醇单乙醚的选择性明显高于间歇釜式反应器.     

磁稳定床己内酰胺加氢精制新工艺

对气液固三相搅拌釜反应器与液固磁稳定床反应器串联的己内酰胺加氢精制过程进行了研究,研究了各种操作参数对反应结果的影响,考察了催化剂的稳定性。实验结果表明,采用该工艺可使w(己内酰胺)=30%的水溶液的高锰酸钾值从50s提高到3000s以上,催化剂寿命3200h。与工业上釜式己内酰胺加氢精制工艺相比,催化剂耗量可降低70%。     

液体喷射环流反应器在2，3，5-三甲基苯醌合成中的应用

在直径149mm液体喷射环流反应器热膜装置中采用空气氧化法对2,3,5-三甲基苯醌合成中三甲基苯酚氧化成三甲基苯醌过程进行了研究.与釜式反应器相比,反应时间由4小时缩短1小时,目的产物的含量由88%提高至98%,催化剂用量降低了70%,溶剂比例减小50%.研究工作为工业应用提供了依据.     

N-乙烯基己内酰胺的合成工艺改进与产品纯化

用乙炔作乙烯化剂,高压法合成出标题化合物,最佳工艺条件优化:在放大时最佳的脱水条件是加入溶剂比为1.0∶0.2;在反应温度90～120℃,反应时间8.0～9.0h,压力1.0～2.0MPa;以水作结晶溶剂,水的用量比例最低为1.0∶1.0;用气相色谱-质谱联用仪(GC/MS)和红外光谱检测表明,简单蒸馏得到w(NVCL)=92%～96%(气相色谱GC)的样品,经进一步精馏分离可得到质量分数99%(GC)以上的NVCL产品。     

醋酸锌/炭小球催化剂的制备及其催化合成醋酸乙烯性能

以炭小球(SAC)为载体,采用过量浸渍法制备了不同醋酸锌负载量的醋酸锌/炭小球催化剂,在常压固定床反应器上,考察了醋酸锌负载量、反应温度、乙炔和醋酸摩尔比、空速等因素对乙炔合成醋酸乙烯的影响。采用SEM,BET,XRD等表征手段研究了催化剂活性降低的机理。研究表明,活性组分的流失和反应过程中形成的少量积炭是催化剂活性下降的2个重要原因。当催化剂中醋酸锌负载量(质量分数)为32.05%,常压,反应温度220℃,C2H2/HAc摩尔比为3∶1,乙炔体积空速为500 h-1,反应110 h后,醋酸的单程转化率为24.20%,醋酸乙烯选择性为98.50%,醋酸锌/炭小球催化剂催化合成醋酸乙烯的生产能力可达2.95 g/(mL.d),比高比表面活性炭催化剂的生产能力高35.32%,且该催化剂具有良好的催化活性、醋酸乙烯选择性和反应稳定性。     

甲醇羰基合成碳酸二甲酯的气相连续性工艺

对甲醇氧化羰基化法合成碳酸二甲酯(DMC)的釜式反应过程,进行了原料气的气相连续性工艺研究.实验结果表明,在CO/O2的物质的量比为2∶1,流量分别为200和400 mL/min,反应压力为2.8 MPa,反应温度为95 ℃,反应时间为6 h条件下,当铜基催化剂浓度为0.25 g/mL时,甲醇转化率为46.8%以上,DMC选择性达到93.1%;当铜基催化剂浓度为0.32 g/mL,甲醇转化率达到54.7%,DMC选择性达到93.1%.     

己内酰胺钠催化剂合成MC尼龙的研究

研究了己内酰胺钠的制备及用己内酰胺钠作催化剂合成MC尼龙的方法,并与氢氧化钠作催化剂合成的MC尼龙作了性能对比。结果表明,使用己内酰胺钠催化剂合成的MC尼龙的转化率、吸水率、力学性能基本保持不变,但加入己内酰胺钠后可不抽真空,因此可以大批量生产,提高生产效率。     

己内酰胺生产的绿色化

己内酰胺生产的绿色化关键是环己酮肟贝克曼重排工艺路线替代的开发。重点介绍了代替浓硫酸催化该反应的固体酸催化剂、催化剂的失活与再生、反应器工业化的方法的进展。提出采用多相催化剂取代发烟硫酸使环己酮肟转化为己内酰胺的工艺 ,该催化剂具有转化率和选择性高 ,易处理再生 ,且可用于连续化工业生产     

温和催化液相重排制备ε-己内酰胺

以对甲苯磺酰氯(TsCl)作催化剂,乙腈为溶剂,催化环己酮肟液相贝克曼重排制备ε-己内酰胺。考察了不同的催化体系、反应温度、反应时间、催化剂用量、溶剂用量等因素对反应的影响,建立了适宜的反应条件:环己酮肟2.0 g,对甲苯磺酰氯1.5 g,乙腈20 mL,反应温度60℃,反应时间2.5 h,环己酮肟转化率达98.4%,ε-己内酰胺选择性达93.6%。该法反应条件温和,操作简单,溶剂乙腈可重复使用。     

高浓度己内酰胺在磁稳定床反应器中加氢精制研究

对高浓度(0．9)己内酰胺水溶液在磁稳定床反应器中加氢精制过程进行了研究,探讨了各种操作参数对反应结果的影响,考察了催化剂的稳定性。实验结果表明,采用该工艺可使质量分数为0．9的水溶液的高锰酸钾值从50s提高到300s以上,催化剂寿命1200h。与工业釜式己内酰胺加氢精制工艺相比,催化剂用量可降低50％。     

Synthesis of N-vinyl caprolactam

The synthesis of N-vinyl caprolactam (NVCL), with acetylene as alkylene agent, was studied in a stirred reactor system. With potassium hydroxide (KOH) being used as catalyst and 18-crown-6 ether as cocatalyst, NVCL was synthesized by the reaction of acetylene with caprolactam (CL). Crude products were purified by vacuum distillation. The addition of 18-crown-6 ether accelerates the reaction rate of the nucleophilic addition much greatly. The initial explanation suggests that the hole radius of 18-crown-6 ether is close to the one of K⁺. A complex is formed between 18-crown-6 ether and K⁺ ion on the formed intermediate of potassium caprolactam, so the addition reaction between acetylene and caprolactam was accelerated greatly. In the stirred tank reactor (500 mL four flask bottle), the CL conversion is 30.5% and the product selectivity is up to 73.4%. The experimental data indicate that the product mixture is a non-ideal liquid mixture. A single process of distillation is difficult to obtain a high purity NVCL product. The combination of extraction and distillation is an ideal separation process for producing high purity NVCL.     

The Preparation of Imidacloprid in a Jet Loop Reactor

A new process for the direct combination of 2-chloro-5-chloromethylpyridine and 2-nitroiminoimidazolidine under benzyltriethylammonium chloride (BTEAC) as the catalyst and butanone as the solvent to yield imidacloprid in an 11.5 L jet loop reactor was developed. Five main reaction conditions including reaction temperature, molar ratio of BTEAC to 2-nitroiminoimidazolidine, concentration of 2-nitroiminoimidazolidine, jet liquid flow rate, and the ratio of the inside diameter of the draft tube to that of the reactor were investigated and optimized. The average molar yield and purity of imidacloprid increased to approximately 80% and 92% under the optimum operating conditions, respectively. Finally, a comparison of the efficiency for the preparation of imidacloprid between the jet loop reactor and the stirred tank reactor under the same operating conditions was conducted.     

The Preparation of Imidacloprid in a Jet Loop Reactor

A new process for the direct combination of 2-chloro-5-chloromethylpyridine and 2-nitroiminoimidazolidine under benzyltriethylammonium chloride (BTEAC) as the catalyst and butanone as the solvent to yield imidacloprid in an 11.5 L jet loop reactor was developed. Five main reaction conditions including reaction temperature, molar ratio of BTEAC to 2-nitroiminoimidazolidine, concentration of 2-nitroiminoimidazolidine, jet liquid flow rate, and the ratio of the inside diameter of the draft tube to that of the reactor were investigated and optimized. The average molar yield and purity of imidacloprid increased to approximately 80% and 92% under the optimum operating conditions, respectively. Finally, a comparison of the efficiency for the preparation of imidacloprid between the jet loop reactor and the stirred tank reactor under the same operating conditions was conducted.     

A consecutive microreactor system for the synthesis of caprolactam with high selectivity

A microreactor system containing two consecutive microreactors and a stirred vessel was developed for the improvement of selectivity of caprolactam (CPL) synthesis. The first microreactor was used to conduct the reaction of cyclohexanecarboxylic acid and oleum, and 97% selectivity for the intermediate product, named mixed anhydride, was obtained. The mixed anhydride then quickly reacted with nitroso‐sulfuric acid in the second microreactor, and the reaction was completed in the vessel, where CPL selectivity reached 93.9%, a much higher value than that achieved either in a control experiment with a batch reactor or in industrial process. The advantage of microreactors is that they can provide high‐quality mixed anhydride and can mix it quickly with the nitroso‐sulfuric acid prior to reaction in the vessel reactor, which, from an engineering standpoint, gives better performance than the traditional syringe‐fed method that is common in chemical synthesis. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1959–1967, 2015     

液体喷射环流反应器的研究(Ⅰ)--"DSD酸"合成中非水介质法氧化过程的应用

在直径149mm液体喷射环流反应器热模装置中对"DSD酸"合成中非水介质法氧化过程进行了研究.与釜式反应器相比,反应时间由5小时缩短至25分钟,目的产物的含量由52%提高至97%,耗碱量降低了50%,能耗降低了20%.研究工作为工业应用提供了依据.     

Investigation of the local specific energy dissipation rates in a jet‐zone loop reactor for halogenation of ketones

Within the framework of process intensification there is a growing demand for novel reactor technologies. For the improvement of halogenation of ketones a jet‐zone loop reactor (JZR) is used, which leads to an enormous increase in yield and selectivity compared to stirred vessels (Kutschera et al., 2008 ). This JZR is a special jet loop reactor with high specific mass transfer performance and good macromixing behaviour. It is obvious that there is direct relation between the reaction and the hydrodynamics in the reactor. Despite several aspects of hydrodynamics in jet loop reactors have been investigated, the essential flow characteristics behind a two‐component jet are not sufficiently understood. In these investigations, the flow field in the jet zone of the JZR was analysed by 2D particle image velocimetry (PIV) and the kinetic energy dissipation rate ε was determined from the spatial gradients of the fluctuating velocity.     

Über die Auswahl von Polymerisationsreaktoren

Choice of polymerization reactors . Industrial syntheses of polymers always yield a highly complex product whose adequate characterization often requires application-oriented tests in addition to chemical and physical parameters. In contrast to the synthesis of low-molecular mass substances subsequent corrections, e. g. by distillation or crystallization, are usually impossible. Extremely detailed reaction control is of paramount importance. Polyreactions can be classified according to kinetic aspects (monomer linkage with and without termination reaction, linkage of polymers). Apart from homogeneous bulk polymerization, there are the heterogeneous processes of precipitation-, bead-, and emulsion-polymerization. The polymerization reactors can be assigned to the known ideal types (batch reactor, continuous plug flow reactor, series of stirred tanks, and continuous stirred tank reactor). High viscosity often thwarts thorough mixing in bulk polymerization and segregation may occur. The article surveys the variants of the reactor types used for various polyreactions and polymerization processes in industry and examines the reasons for this choice. Most commonly used is the batch reactor, followed by the cascade of stirred tanks. Continuous polymer-linkage (polycondensation, polyaddition) is frequently performed in a series of several different kinds of reactors.     

Deacidification of a synthetic oil with an anion exchange resin

Esters of trimethylolpropane were prepared by reaction of trimethylolpropane with erucic acid. Unreacted erucic acid was eliminated by fixation on an anion exchange resin to produce an oil with a low free fatty acid content. The authors describe the deacidification of the reaction product by Lewatit MP500A and MP600 resins in a fixed-bed reactor or in a stirred reactor. The discontinuous process gave the best results with the Lewatit MP600 resin in a stirred reactor with a 99% yield. The acid value was below 0.1 after less than 1 h of contact.     

氯乙烯精馏过程的模拟及优化

利用化工流程模拟软件 Aspen Plus,对电石乙炔法工艺中的氯乙烯精馏过程进行模拟.精馏全流程的模拟结果与实际生产数据基本吻合.对低沸塔和高沸塔的进料位置、回流比等参数进衍了优化.精馏过程的产品纯度提高到99.67%,低沸塔塔顶冷凝器的冷量消耗减少了17.4%,再沸器蒸汽消耗量减少了10.1%.     

Continuous reactive crystallization of pharmaceuticals using impinging jet mixers

For reactive crystallization of pharmaceuticals that show a rapid reaction rate, low solubility of active pharmaceutical ingredient and hence a large supersaturation, it was found in a recent study that a process design which integrates an impinging jet mixer and batch stirred tank produces high quality crystals. The current investigation examines if the short processing time of reactive crystallization permits the impinging jet mixer—stirred tank design to be modified to operate in a continuous mode. The new design combines an impinging jet mixer for feed introduction and reaction with a continuous stirred tank reactor (CSTR) and tubular reactor for crystal growth. A study of reactive crystallization of sodium cefuroxime (an antibiotic), using first a 1L CSTR then scaling to a 50L CSTR, found that the new design produces crystals of higher crystallinity, narrower particle size, and improved product stability, than batch crystallizers. © 2016 American Institute of Chemical Engineers AIChE J, 63: 967–974, 2017