微通道反应器在芳香化合物硝化反应中的应用进展

芳香化合物的硝化是常用的生产单元,采用传统釜式反应器进行硝化反应存在放热量大、选择性低、浪费资源、污染环境、存在安全隐患等问题。微通道反应器具有优良的传热、传质性能,可有效解决传统釜式反应器存在的问题,是一种安全、环保、高效的新型反应设备。综述了微通道反应器在芳香化合物硝化反应中的应用进展,包括以苯型芳香烃为底物的硝化反应及以非苯型芳香烃为底物的硝化反应。     

微流控双水相贴壁液滴流动强化酶促反应研究

以微流控双水相液滴流技术为基础,开发了一种酶促反应平台,将微流控贴壁液滴流快速传递、高效混合的特点与双水相反应分离耦合过程优化结合。本体系克服了传统宏观双水相体系传质传热慢以及耗时耗能的问题,并建立了贴壁液滴微反应器,产生更大的内环流,进一步增强传质效果。探究了双水相液滴界面的分子限域能力、对酶和产物的选择性分配能力。通过比较贴微通道壁和未贴微通道壁两类液滴微反应器的酶促反应效果,发现贴微通道壁液滴微反应器仅6 min转化率即可达到40%,其反应速率可达未贴微通道壁液滴微反应器9.4倍。本文通过微流控双水相贴壁液滴流实现了酶促反应的强化,为微尺度下的酶催化反应过程强化提供了一种新的思路。     

微通道反应器中环己烷液相氧化反应工艺的研究

以纯氧为氧化剂、环己酮为引发剂和环烷酸钴(II)为催化剂,研究了内径为0.762 mm、长度为20 m的微通道反应器内环己烷液相氧化的反应行为,考察了表观气体流速、表观液体流速、反应温度、压力和催化剂用量等因素对环己烷转化率和产物选择性的影响。在氧气和环己烷表观流速分别为1.80 m?s-1和0.004 m?s-1、温度165℃、压力1.4 MPa、环己酮加入量0.2%(wt)和催化剂钴(II)浓度为10 ppm时,环己烷的转化率为4.57%,环己醇、环己酮和环己基过氧化氢的选择性分别为61.72%、34.87%和1.12%,己二酸的选择性小于3.0%。结果表明,微通道反应器中进行环己烷液相催化氧化,能有效提高气液相界面积,加快环己烷氧化反应速率,降低副产物的生成。     

苯二甲酸的连续硝化反应研究

以邻苯二甲酸酐、间苯二甲酸和对苯二甲酸为原料,在连续流反应器中采用硝酸/硫酸混酸工艺合成了苯二甲酸硝基衍生物,研究了反应温度、硝酸/硫酸配比及用量、停留时间等对反应的影响。结果表明:对苯二甲酸硝化不适用于在连续化反应器中进行;间苯二甲酸在微通道反应器中硝化的最优条件为:n(间苯二甲酸):n(发烟硝酸):n(浓硫酸)=1:1.7:7,反应温度为75℃,保留时间为40.9 s,转化率为99.8%,5-硝基间苯二甲酸产率为95%,选择性为100%;邻苯二甲酸酐在微通道反应器中硝化的最优条件为:n(邻苯二甲酸酐):n(发烟硝酸):n(浓硫酸)=1:1.5:3,反应温度为90℃,保留时间为60.6 s,转化率为100%,3-硝基邻苯二甲酸收率为37%,选择性为41.3%。     

微通道反应器内氯苯硝化反应研究

在微通道反应器内对氯苯硝化反应进行了研究,考察了氯苯与硝酸的摩尔比、体积流速、反应温度等对单程转化率及选择性的影响。实验选择了较优工艺参数组合:n(氯苯)∶n(硝酸)=1∶1.3,n(硝酸)∶n(硫酸)=1∶3,氯苯体积流速0.5 mL/min,反应温度80℃,氯苯单程转化率达74.8%,n(邻硝基氯苯)∶n(对硝基氯苯)=0.56∶1,时空转化率(STC)达4.07×109mol/(m3.h)。微通道反应器内,时空转化率是常规反应器的3.08×104倍。     

微反应技术在橡胶助剂生产中的应用研究

<正>微反应器,即微通道反应器,利用精密加工技术制造的尺寸在10~300微米(或者1000微米)之间的微型反应器。微反应器表示工艺流体的通道在微米级别,而不是指微反应设备的外形尺寸小。由于微反应器具有较大的比表面积,可达搅拌釜比表面积的几百倍甚至几千倍,有着极好的传热和传质能力,可以实现物料的瞬间均匀混合和高效的传热,因此许多在常规反应器中无法实现的反应都可以在微反应     

用微反应器实现可见光驱动的不对称氧化连续化反应

将可见光催化、不对称合成、分子氧氧化和连续化集成,创新性地用玻璃微通道反应器实现可见光活化分子氧氧化的β-酮酸酯类化合物的不对称α-羟基化反应的连续工艺。用金鸡纳碱衍生的相转移有机催化剂在气-液-液多相体系内实现可见光催化,分子氧不对称氧化连续反应。在心形微通道反应器内,1-茚酮-2-甲酸金刚酯底物完全氧化为(S)-2-羟基-1-茚酮-2-甲酸金刚酯,产物收率95%,对映选择性87.0%。与间歇反应相比,采用微反应器的连续反应在保持产物高立体选择性基础上将30 min反应停留时间缩短至1.08 min。该方法具有快速、低能耗、连续、高效等优势,具有良好的工业化前景。     

丙酮液相氨肟化连续流反应

在液相条件下,以丙酮、氨水和双氧水为原料,钛硅分子筛（TS-1）为催化剂,叔丁醇为溶剂,在具有特殊微结构的连续流微通道反应器中一步氧化合成丙酮肟。实验考察了双氧水浓度、氨水用量、双氧水用量、溶剂用量、助催化剂用量以及温度对氨肟化的影响,结果表明：AFR微通道反应器中,反应器出口压力5 bar,温度100 ℃,催化剂浓度8 g/mol（mol为丙酮的单位）,氨水/双氧水/叔丁醇/丙酮摩尔比=3:1.1:6:1,双氧水浓度70 wt.%,氨水浓度25 wt.%,助催化剂浓度3 mg/mol（mol为丙酮的单位）,停留时间72 s,获得丙酮转化率为80%,丙酮肟选择性为97%,丙酮肟的收率为77%。AFR微通道反应系统持液量小、停留时间短、强传质传热等特点,强化了反应物料和催化体系之间的协同效应,提高了氨肟化反应速率,解决了双氧水分解带来的氨肟化反应本质安全问题,实现了丙酮氨肟化的绿色安全高效合成。     

生物柴油制备过程中反应器的研究进展

叙述了管式和滴流床等传统反应器和膜反应器、微通道反应器、反应蒸馏反应器等新型反应器在生物柴油制备的应用和发展,并对反应器的应用前景做了评述和展望。认为改进的传统反应器和新型反应器在生物柴油生产中都有一定的发展前景。新型反应器仍需要解决一些基本的过程问题,如微通道反应器的平行放大控制、腐蚀,膜反应器的选择性．反应蒸馏反应器的模型放大优化问题。     

用微反应器实现可见光驱动的不对称氧化连续化反应

将可见光催化、不对称合成、分子氧氧化和连续化集成,创新性地用玻璃微通道反应器实现可见光活化分子氧氧化的β-酮酸酯类化合物的不对称α-羟基化反应的连续工艺。用金鸡纳碱衍生的相转移有机催化剂在气-液-液多相体系内实现可见光催化,分子氧不对称氧化连续反应。在心形微通道反应器内,1-茚酮-2-甲酸金刚酯底物完全氧化为(S)-2-羟基-1-茚酮-2-甲酸金刚酯,产物收率95%,对映选择性87.0%。与间歇反应相比,采用微反应器的连续反应在保持产物高立体选择性基础上将30 min反应停留时间缩短至1.08 min。该方法具有快速、低能耗、连续、高效等优势,具有良好的工业化前景。     

连续微反应加氢技术在脱保护反应中的应用

保护与脱保护是医药中间体等精细化工领域中较为常见的一种有机合成策略。常用的保护基主要有苄基与苄氧羰基,通常可利用催化加氢法将其脱除。采用高压加氢间歇釜工艺存在气液传质效率低,操作安全性差,氢解效率低等问题。采用连续微反应加氢技术进行非均相催化加氢脱保护,可以利用其较高的气液传质效率和平推流特性实现高选择性脱保护,并显著缩短反应时间。本文阐述了连续微反应加氢技术在脱保护反应中的优点及其在药物中间体合成中的实际应用,并介绍了催化剂与溶剂对脱保护反应的影响。最后对连续微反应加氢技术在脱保护中的应用进行了展望。     

Fatty methyl ester hydrogenation to fatty alcohol part I: Correlation between catalyst properties and activity/selectivity

Fatty alcohols, derived from natural sources, are commercially produced by hydrogenation of fatty acids or methyl esters in slurry-phase or fixed-bed reactors. One slurry-phase hydrogenation of methyl ester process flows methyl esters and powdered copper chromite catalyst into tubular reactors under high hydrogen pressure and elevated temperature. In the present investigation, slurry-phase hydrogenations of C₁₂ methyl ester were carried out in semi-batch reactions at nonoptimal conditions (i.e., low hydrogen pressure and elevated temperature). These conditions were used to accentuate the host of side reactions that occur during the hydrogenation. Some 14 side reaction routes are outlined. As an extension of this study, copper chromite catalyst was produced under a number of varying calcination temperatures. Differences in catalytic activity and selectivity were determined by closely following side reaction products. Both activity and selectivity correlate well with the crystallinity of the copper chromite surface; they increase with decreasing crystallinity. The ability to follow the wide variety of side reactions may well provide an additional tool for the optimized design of hydrogenation catalysts.     

蒽醌法制过氧化氢用氢化反应器的研究进展

综述了近年来蒽醌法生产过氧化氢用悬浮氢化反应器和固定床氢化反应器的研究进展。着重介绍了管式和鼓泡床 悬浮氢化反应器的改进和泡沫固定床三相反应器用于蒽醌氢化过程可显著提高反应时空收率和选择性的优势。指出泡沫固定 床是蒽醌氢化反应器研究开发中的新思路,也是气-液-固三相反应器研究的新方向。     

Microstructured reactors and supports for ionic liquids

Different types of microstructures and their applications with respect to the synthesis and the use of ionic liquids are presented. Microstructured reactors are suitable for reactions with fast intrinsic kinetics, requiring high mass and heat transfer performances. Chemical synthesis can be performed safely under operating condition (e.g. high temperature, pressure, etc.) difficult to obtain in traditional reactors. The examples presented clearly indicate that microstructured reactors offer superior performance for the synthesis of ionic liquids in comparison to conventional equipment. For the use of ionic liquids as reaction media, existing ionic liquids show some limitations due to their higher viscosity compared to conventional solvents. Therefore, future research should be focused on the development of low viscosity ionic liquids.The approaches to use ionic liquids in microstructured reactors and in combination with microstructured supports for catalytic reactions show many advantages in view of high product selectivity and yield. The use of supported ionic liquids on microstructured materials seems to be particularly promising for gas phase as well as for gas/liquid reactions.     

Activity and selectivity control in iron catalyzed Fischer-Tropsch synthesis

We present results of a catalyst structure-function study that supports a CO hydrogenation model with -olefins formed as the principal primary products and n-paraffins formed during secondary hydrogenation reactions. The interplay of catalyst composition and reaction environment controls the extent of secondary reactions. Catalysts that contain mainly oxidic phases or carbides with large concentrations of excess matrix carbon favor secondary reactions. The relative concentrations of oxide and carbide phases depends on the ease of reduction of the catalyst, which can be changed by cation substitutions. For example, cobalt substitution into Fe₃O₄ lowers the reduction temperature by 20 ° C. Excess matrix carbon has been intentionally introduced (by treatment in high temperature H₂/CO) into model iron carbide catalysts produced by laser synthesis. Increased paraffin selectivity as matrix carbon is introduced suggests the influence of the diffusion constraints on product selectivity. Alkali promotion will affect secondary hydrogenation pathways. We illustrate how catalysts with low levels of alkali become increasingly more selective to paraffins at high conversions (and high effective H₂/CO ratios).Reaction environment also controls catalyst composition and selectivity. Mossbauer spectroscopy on spent catalysts suggests that oxide/carbide phase formation in iron catalysts are sensitive to reactor configuration (extent of backmixing). In integral fixed bed reactors, catalysts partition into carbide phases in the front of the bed but show increasing amounts of oxide near the exit, whereas the catalysts in the stirred tank reactor remain all carbides. Product selectivities reflect the phase differences.Other examples illustrating secondary hydrogenation phenomena will be presented.     

催化转移加氢及其在有机合成中的应用

催化转移加氢法是有机合成中常用的一种加氢方法,由于使用的氢源不是氢气,而是其他一些含有氢的多原子化学物质,使得其加氢过程与用氢气的加氢过程相比, 具有安全性高、反应温度低、设备要求低和选择性高等优点。催化转移加氢法在均相有机合成中的应用十分广泛,尤其在不对称合成中应用更为广泛。此外,在多相催化加氢中也有十分广泛的用途,并对催化转移加氢法的特点及在有机合成中的主要用途进行了评述。     

A simulation study of industrial vegetable oil hydrogenation reactors

A mathematical model has been developed to predict the course of industrial vegetable oil hydrogenation reactors. The model assumes that the reaction is mass-transfer-controlled. Suitable empirical equations have been used to describe rate of hydrogenation in preference over a mechanistic approach. The agreement between theoretical predictions from the model and plant data is generally satisfactory. Temperature, pressure and agitation intensity have strong effect on the kinetics of the reaction and on selectivity ratio under conditions of industrial reactors. The product quality is determined by overall selectivity which is governed by operating conditions, as well as the catalyst selectivity. D.N. Saraf, Currently on leave at the Petroleum Recovery Institute, Calgary, Alberta, Canada.     

Model for the coal hydrogenation process and its applications

A coal hydrogenation model has been formulated which incorporates both chemical and microscopic experimental data. In this generalized model, carbonization and hydrogenation are viewed as concurrent processes in the liquefaction of coal. Insufficient hydrogen availability, rapid heating rates and long reaction times at elevated temperatures can promote carbonization reactions. The model describes in detail the reaction pathways involved in the hydrogenation of both inertinite and vitrinite. When vitrinite is hydrogenated in the presence of a hydrogen donor solvent, a plastic material called vitroplast is formed. The vitroplast is either converted to liquid and gaseous products when hydrogen availability is high or becomes mesophase and then semicoke when hydrogen availability is low. Even under favourable hydrogenation conditions, the major reaction pathway in the hydrogenation of inertinite is one of initial mild carbonization followed by hydrogenation. It is evident that the difference in hydrogenation behaviour between vitrinite and inertinite is due, in part, to the ability of the hydrogen donor solvent to penetrate vitrinite but not inertinite particles. The hydrogenation model is useful for explaining various phenomena that occur during hydrogenation, such as the formation of mesophase and semicoke, and the blockage of reactors and preheaters.     

CuZnTiO2/SAPO-34双功能催化剂的设计、制备及其用于CO2加氢制烯烃性能

CO₂加氢经甲醇（含氧中间体）制低碳烯烃工艺路线，可实现成醇、脱水两步反应串联协同进行，打破费托合成产物Anderson-Schulz-Flory（ASF）分布限制，高选择性地制取低碳烯烃。传统甲醇合成Cu基催化剂加氢能力较强，在两步反应中产物以CH₄、低碳烷烃为主。实验设计、制备了CuZnTiO₂/(Zn-)SAPO-34复合催化剂，实现了CO₂加氢在Cu基复合催化剂上高选择性合成C₂～C₄烯烃（约60%）。研究表明，两步反应过程中甲醇体积分数较低（＜6%），且高温下逆水煤气变换反应严重，导致催化剂酸性变化对产物分布的影响较大。调变两类活性位点比例发现，CH₄的产生与串联反应存在竞争关系，SAPO-34酸量的增加抑制了CH₄的生成，促进串联反应正向进行；合适的酸性有助于生成C₂～C₄烯烃。控制成醇、脱水两类活性位点接触距离可调变烯烃的二次反应，降低加氢能力，改善产物分布。     

不对称催化合成手性泛解酸内酯的研究进展

泛解酸内酯是合成D-泛酸钙和D-泛醇的重要中间体,国内主要采用生物拆分法,虽取得一定进展,但存在底物浓度偏低、反应条件苛刻、光学纯度不高和催化剂活性不强等问题。化学不对称合成法成为近年来制备手性泛内酯的研究热点。根据手性源的不同,介绍过渡金属配合物催化不对称还原酮基泛内酯,过渡金属配合物催化羟醛缩合反应,有机小分子及其衍生物不对称催化羟醛缩合反应并经还原内酯化合成泛内酯以及光学活性化合物作为反应底物或非手性底物中加入手性助剂的合成手性泛内酯工艺。其中,有机小分子催化乙醛酸酯与醛的反应表现出良好的催化效果,且催化剂易得,反应条件温和,操作简单。缩合产物的收率和对映选择性均不高,设计具有高活性和高选择性的有机小分子手性催化剂是今后研究的重点。