基于连续流微通道反应器合成盐酸金刚烷胺工艺研究

为解决传统釜式反应在盐酸金刚烷胺制备过程中存在的反应时间长、返混大等问题,通过连续流微通道反应器,以1-溴代金刚烷、尿素、盐酸等为原料对盐酸金刚烷胺进行了制备,其结构通过高分辨质谱(HRMS)和核磁氢谱(1H NMR)得到了证明。进而对其制备条件进行了考察,重点考察了反应物料摩尔比、停留时间、反应温度、反应压力等影响因素对产物产率的影响。实验结果表明,实验条件下,当物料摩尔比为1∶4、反应温度为100℃、反应停留时间为15 min,产物产率可高达90%,为最佳工艺条件。该工艺极大地提高了此反应合成盐酸金刚烷胺的工艺转化率,为其工业化应用提供了技术指导。     

微通道反应器中合成埃克替尼中间体的连续流工艺研究

在微通道反应器中,以2,3,5,6,8,9-六氢-1,4,7,10-苯并四氧基环十二烷-12-羧酸乙酯(BPI02)和硝酸为原料,设计连续合成埃克替尼中间体2,3,5,6,8,9-六氢-13-硝酸-1,4,7,10-苯并四氧基环十二烷-12-羧酸乙酯(BPI03)的新工艺。考察反应温度、反应物料摩尔比以及原料进料流速对反应的影响。结果表明:最佳工艺条件为70%HNO_3 作硝化剂,n(BPI02)∶n(硝酸)=1∶6、反应温度70℃、反应系统总通量为97.5 mL/min。在最佳工艺条件下,BPI02的转化率可达到99.22%,产物BPI03的选择性可以达到92.23%。与传统生产工艺相比,微通道反应器实现了连续化操作,提高了生产效率以及安全性。     

微通道中硝基胍的连续流合成工艺研究

以硫酸胍和硝硫混酸为原料,在微通道中进行管式流动硝化反应,形成了硝基胍的连续流合成工艺。研究了混酸浓度、反应温度、停留时间、物料摩尔比等工艺参数对合成反应的影响。获得的优化工艺参数为：90%HNO3:98%H2SO4=2:1(v/v),反应物与硝酸摩尔配比为1:1.2,反应温度为60 ℃,停留时间为30 s,此时硫酸胍的转化率为87.9%,硝基胍收率为86.1 %。与传统间歇釜式合成工艺相比,连续流工艺实现了硝基胍合成反应的稳定进行,消除了过程反应热的积累和温度波动,解决了硝基胍的合成安全性问题,缩短了反应时间,提高了产率,减少了废酸排放量。     

微通道连续流反应器用于传统搅拌釜的工艺改造

采用康宁公司的G1微通道连续流反应器对传统的HATP搅拌釜工艺进行了改造和优化,考察了溶剂使用、反应温度、反应物摩尔当量、流速等对反应的影响,进一步优化了工艺条件。改进后的工艺产品质量分数可达98%,目标产物收率近100%,可实现年产30 t HATP,不再使用任何有机溶剂,实现了整个工艺过程的零排放连续操作。     

微通道中硝基胍的连续流合成

以硫酸胍和硝硫混酸为原料,在微通道中进行管式流动硝化反应。考察了混酸浓度、反应温度、停留时间、物料比对反应的影响。获得的优化工艺参数为:V(质量分数80%HNO_3)∶V(质量分数98%H_2SO_4)=2∶1,n(硫酸胍)∶n(硝酸)=1∶1.2,反应温度为60℃,停留时间为30 s,此时硫酸胍的转化率为87.9%,硝基胍收率为86.1%。与传统间歇釜式合成工艺相比,连续流工艺实现了硝基胍合成反应的稳定进行,消除了过程反应热的积累和温度波动,缩短反应时间。     

间硝基苯乙酮在微通道反应器中的连续流合成研究

在碳化硅材质微通道反应器中,以苯乙酮为原料、硝酸为硝化剂、浓硫酸为溶剂合成间硝基苯乙酮。考察反应物料摩尔比、混酸摩尔比、反应温度、反应停留时间等工艺参数对反应的影响并对其进行优化。结果表明,当n(苯乙酮)∶n(硝酸)∶n(硫酸)=1∶1.5∶2、反应体系温度为10℃、停留时间为110 s时,反应效果最佳。该工艺充分利用了微通道反应器优良的传质传热特点,有利于对反应的精确控制和降低能耗,并减少副反应的发生。     

合成间甲基苯甲酸的微通道连续流工艺

目前,对合成间甲基苯甲酸的研究主要局限于氧化釜的间歇反应工艺,对连续流反应工艺少有报道。针对这一问题,本文提出了在脉冲混合结构微通道反应器中液相氧化合成间甲基苯甲酸的连续流工艺。采用间二甲苯为原料,过氧乙酸为氧化剂,乙酸钴和溴化钠为催化剂,通过对反应物料比、催化剂的用量、反应停留时间、反应温度、溶剂用量等条件的考察,获得最佳工艺条件。得出当n（间二甲苯）∶n（过氧乙酸）∶n（乙酸钴）∶n（溴化钠）∶n（乙酸）=1∶4∶0.015∶0.02∶5、反应温度120℃、反应停留时间15min时,反应效果最佳。研究结果表明：此工艺充分利用微通道连续流反应器优良的传质传热特点,大大缩短了反应时间,提高了反应速率,扩大工艺条件选择区间,增加了安全系数,实现对氧化反应过程的有效控制。     

微通道反应器在危险工艺中的应用研究

本文综述了微通道反应器技术在危险工艺的应用研究进展,展开叙述了微反应器技术在硝化工艺、氧化工艺、过氧化工艺、氯化工艺、加氢工艺、磺化工艺的中的应用。微反应器使危险工艺变得相对安全,在化工行业有着广泛的发展前景。     

邻二氯苯合成3,4-二氯硝基苯的连续流工艺研究

以邻二氯苯为原料、硝酸为硝化剂、浓硫酸为溶剂,研究了在脉冲混合结构微通道反应器中合成3,4-二氯硝基苯的连续流工艺,考察了反应物料摩尔比、硝硫混酸摩尔比、反应温度、反应停留时间等工艺条件。结果表明,当n(邻二氯苯)∶n(硝酸)∶n(硫酸)=1∶2∶4、反应体系温度为60℃、停留时间为135 s时,反应效果最佳。该工艺充分利用了微通道反应器优良的传质传热特点,缩短了反应时间,扩大了工艺条件选择区间,实现了对反应过程的有效控制,增加了安全系数。     

双氧水氧化乙二醛合成乙醛酸的连续流工艺

以乙二醛和双氧水为原料,在微通道反应器中考察了液相氧化合成乙醛酸的连续流工艺。考察了物料比、催化剂用量、双氧水浓度、停留时间、温度等对反应的影响。确定该法最佳工艺条件为,n(乙二醛)∶n(H_2O_2)∶n(FeSO_4)=1.0∶1.0∶0.13,双氧水浓度1.67 mol/L,停留时间10 min,反应温度30℃。在该条件下,乙二醛转化率达到94.7%,乙醛酸选择性达到85.4%。该工艺充分利用微通道反应器优良的传质传热特点,大大缩短了反应时间,提高了反应速率,扩大了工艺条件选择区间,实现了对氧化反应过程的有效控制,增加了安全系数。     

微管反应器中硝基氯苯的连续合成

芳香族化合物的硝化是快速、强放热反应,采用连续硝化工艺可降低间歇操作可能引起的潜在风险。本文采用可视化方法和计算流体力学（CFD）模拟研究微管内流动状况的基础上,在体积为10mL的微管反应器中进行了氯苯连续硝化反应,探究了停留时间、温度、混酸比（硝酸与硫酸的摩尔比）、相比（硝酸与氯苯的摩尔比）对反应转化率、收率、产物邻对比和选择性的影响。结果表明,氯苯和混酸两相在内径为1mm的微通道内呈现出的Taylor流流型可以强化传质传热的效率,提高宏观反应速率。在停留时间为8min、温度80℃、混酸比=1∶1.5、相比=1∶1时,产物中邻对比在0.7~0.8之间,氯苯单程转化率为81.24%,一硝基氯苯的选择性为93.77%。采用连续硝化后,反应停留时间大幅降低,一硝基氯苯的邻对比明显提高。相比于传统釜式工艺,微管反应器内连续硝化更加安全、高效。     

油酸甲酯连续合成工艺及其动力学研究

在固定床反应器中,以阳离子交换树脂为催化剂,油酸与甲醇液液并流反应制备油酸甲酯。考察了反应各影响因素,获得较适工艺条件为:催化剂装载量20 g,醇酸摩尔比2∶1,反应温度60℃,停留时间40 min。在此条件下,油酸转化率可达99.43%。对油酸与甲醇的反应动力学进行了研究,以拟均相模型对实验数据进行拟合,得出30℃、40℃、50℃、60℃下的正、逆反应速率常数。反应速率随温度的升高而加快,二者关系符合Arrhenius方程,该反应的活化能为60.687 kJ/mol。     

Multiphase surfactant-assisted reaction-separation system in a microchannel reactor

The Lewis acid-catalyzed addition of trimethylsilyl cyanide to p-chlorobenzaldehyde in a microchannel reactor was investigated. The microchannel was integrated to promote both reaction and separation of the biphase system. FeF₃ and Cu(triflate)₂ were used as water-stable Lewis acid catalysts. Sodium dodecyl sulfate was incorporated in the organic-aqueous system to enhance the reactivity and to manipulate the multiphase flow inside the microchannel. It was found that the dynamics and the kinetics of the multiphase reaction were affected by the new micellar system. Parallel multiphase flow inside the microchannel was obtained, allowing for continuous and acceptable phase separation. Enhanced selectivity was achieved by operating at lower conversion values.     

Parametric analysis of Fischer‐tropsch synthesis in a catalytic microchannel reactor

Fischer‐Tropsch synthesis (FTS) involves highly exothermic conversion of syngas to a wide range of hydrocarbons, but demands isothermal conditions due to the strong dependence of product distribution on temperature. Running FTS in microchannel reactors is promising, as the sub‐millimeter dimensions can lead to significant intensification that inherently favors robust temperature control. This study involves computer‐based FTS simulations in a heat‐exchange integrated microchannel network composed of horizontal groups of square‐shaped cooling and wall‐coated, catalytic reaction channels. Effects of material type and thickness of the wall separating the channels, side length of the cooling channel, coolant flow rate, and channel wall texture on reaction temperature are investigated. Use of thicker walls with high thermal conductivities and micro‐baffles on the catalytic reaction channel wall favor near‐isothermal conditions. Response of reaction temperature against coolant flow rate is significant. Using cooling channels with smaller side lengths, however, is shown to be insufficient for temperature control. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Controllable preparation of nano-CaCO3 in a microporous tube-in-tube microchannel reactor

In this work, nano-CaCO₃ particles with tunable size have been synthesized via CO₂/Ca(OH)₂ precipitation reaction in a microporous tube-in-tube microchannel reactor (MTMCR) with a throughput capacity up to 400 L/h for CO₂ and 76.14 L/h for liquid. The overall volumetric mass-transfer coefficient (K_La) of CO₂ absorption into Ca(OH)₂ slurry in the MTMCR has been deduced and analyzed. To control the particle size, the effect of operating conditions including initial Ca(OH)₂ content, gas volumetric flow rate, liquid volumetric flow rate, micropore size, and annular channel width was investigated. The results indicated that the mass transfer in the MTMCR can be greatly enhanced in contrast with a stirred tank reactor, and the particle size can be well controlled by tuning the operating parameters. The nano-CaCO₃ particles with an average size of 28 nm and a calcite crystal structure were synthesized, indicating that this process is promising for mass production of nanoparticles.     

Continuous emulsion polymerization of styrene in a single Couette–Taylor vortex flow reactor

The effect of the geometrical and operational parameters on the mixing characteristics of a Couette–Taylor vortex flow reactor (CTVFR) were investigated and were correlated with the same parameters by using the tank‐in‐series model. Continuous emulsion polymerization of styrene was conducted at 50°C in a CTVFR to clarify the effects on kinetic behavior and reactor performance of operational parameters such as rotational speed of inner cylinder (Taylor number), reactor mean residence time, and emulsifier and initiator concentrations in the feed streams. It was found that steady‐state monomer conversion and particle number could be freely varied only by varying the Taylor number. In order to explain the observed kinetic behavior of this polymerization system, a mathematical model was developed by combining the empirical correlation of the mixing characteristics of a CTVFR and a previously proposed kinetic model for the continuous emulsion polymerization of styrene in continuous stirred tank reactors connected in series (CSTRs). On the basis of these experimental results, it was concluded that a CTVFR is suitable for the first reactor (prereactor) of a continuous emulsion polymerization reactor system. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1931–1942, 2001     

Continuous production of palm methyl esters

A system for continuous transesterification of palm oil was developed using a continuous stirred-tank reactor (CSTR) and pumps for continuous delivery of oil and catalyst and for continuous removal of product. Potassium hydroxide was used as the catalyst, the methanol-to-oil molar ratio was 6∶1, and reaction temperature was 60°C. The yield of methyl esters increased from 58.8% of theoretical yield at a residence time of 40 min to 97.3% at a residence time of 60 min. However, higher residence times decreased the production rate. During long-term continuous operation, the CSTR displayed steady state conditions in terms of product profile and methyl ester concentration. This process has good potential in the manufacture of biodiesel.     

Experimental study and simulation of the polymerization of methyl methacrylate at high temperature in a continuous reactor

The bulk polymerization of MMA at high temperature (120–180°C) in a continuous pilot‐plant reactor has been studied. The polymerization is initiated by diterbutyle peroxide and the chain transfer agent is 1‐butanethiol. A simulation program has been developed to predict the steady state behavior of the reactor. The particular features of the kinetic at above‐T_g temperature are included in the model, especially the thermal initiation of the reation and the attenuation of the autoacceleration effect. For the flow and mixing model, the actual vessel cannot be approximated to a single ideal reactor because of its design and of the moderate agitation imposed by the high viscosity of the reacting fluid. A tanks in series model with a recycle stream between tanks is proposed to evaluate the backmixing caused by the special design of the agitator. The parameters of the model are determined with the help of the experimental residence time distribution measured on the reactor. The data collected on the actual reactor, i.e., operation, conversion, molecular weight, temperature, are compared to the calculated one. The agreement is satisfactory but the tendencies are slightly underestimated. The program is a tool to evaluate the effect of modifications of the design of the reactor or changes on the operation parameters like input rate, temperature, and agitation on its behavior. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2038–2051, 2001