酶促合成油酸香茅醇酯的超临界连续反应-分离过程

将固定床动态酶促反应过程和超临界二氧化碳萃取分离过程相耦合,设计并建立了一套超临界相反应分离一体化的实验装置。在该装置上初步考察了反应压力和温度对脂肪酶催化油酸甲酯和外消旋香茅醇酯交换反应的影响。结果表明,我们所建立的反应装置能有效地实现反应分离一体化过程;当体系压力接近二氧化碳的临界压力时反应速率最高;9MPa压力下反应温度为328K时反应转化率最高,而在14MPa压力下反应转化率在308K～328K之间随着温度的升高而增大。     

从催化导向性基础研究到工业应用的若干创新思路与实践——庆祝闵恩泽先生九十华诞

闵恩泽先生曾经指出:开展导向性基础研究对研发新技术及其实现工业应用至关重要.将高性能催化材料和化学工程技术的结合是石油化工技术创新的重要途径之一.在传统的石油化工领域引入和集成新材料、新工艺与新过程,可有力地推动石油化工技术的发展.本文对近年来在多孔催化新材料及若干石油化工关键催化技术的创新实践进行总结,包括多孔复合催化新材料与工业催化反应的结合、绿色反应工艺与催化剂、过程耦合与强化等几个方面,凝练了材料科学与化学工程结合与应用的创新思路.     

国家重点实验室介绍之四化学工程联合实验室

化学工程联合实验室由精馏分离、萃取分离、固定床反应工程和聚合反应工程四个实验室联合组成,分别设在天津大学(天津)、清华大学(北京)、华东化工学院(上海)和浙江大学(杭州).由著名化工专家、学部委员清华大学汪家鼎教授任实验室主任和著名化工专家、学部委员、南京化工学院时钧教授任学术委员会主任. 化学工程是一个面向经济建设、广泛应用于多种工业的技术基础学科,是基础科学与工程技术之间的桥梁和纽带.它的主要任务是以物理、化学、物理化学、流体力学等学科为基础,研究在工业生产中实现物质和能量的转化与传递的规律,为生产过程的设计、放大、控     

膜与膜反应器:现状、挑战与机遇

膜与膜反应器是实现物质高效分离、反应/分离耦合的重要技术手段,在缓解能源、环境和资源所面临的重大问题方面发挥着日益重要的作用.本文根据膜孔大小和传质分离机理将膜分为大孔膜、微孔膜和致密膜三类,评述了不同种类分离膜的最新研究进展,探讨了进一步发展所面临的瓶颈和可能取得突破的方向,并对近年来以这三类膜为"芯片"的膜反应器在化学工程领域取得的研究进展进行了重点介绍,最后指出膜与膜反应器未来发展应重点关注的领域.     

葡萄糖与苯肼的成脎反应

单糖与苯肼作用生成脎的反应是糖类一个非常重要的反应,成脎反应在分离和鉴别糖的过程中起着决定性的作用。关于成脎反应的机理,许多教科书的说法不一。本文拟就葡萄糖与苯肼的反应,谈谈我们的看法。从国内现行有机化学教科书来看,有些对成脎反应的机理避而不谈,这对解释某些实验现象很不     

应用基础研究推动学科发展取得重大效益——国家自然科学基金"七五"重大项目《传质分离与化学反应工程中若干重要课题的基础研究》通过验收

传质分离和化学反应工程是化学工程学科的两个主要内容,是近代化学加工工业中生产过程开发和设备设计的理论基础。早在80年代初期,我国一批著名的化工专家充分分析了国际上化学工程学科发展的状况和趋势,结合我国工业生产和科研队伍的实情,远见卓识地抓住了传质分离和化学反应工程这两个核心领域作为学科发展的突破口。并建议:发挥我国科技力量的优势,选择在化学工业中使用量大,应用面广的若干典型课题(如溶剂萃取、蒸馏过程、流态化技术、聚合反应工程和固定床反应器等),开展以掌握各过程、设备和技术的规律及其优化放大方法为中心的基础研究和应用研究。期望其研究成果在提高我国化学工业的生产技术水平、促使技术改造、缩短工业放大周期、开拓新的应用领域等方面发挥重大作用,并在有关的理论     

化学工程:从基础研究到工业应用

本文介绍了我国中长期发展规划中所制定的化学化工学科发展目标,综述了化学工程学科近十余年来在队伍建设、平台建设和国家级奖励等方面所取得的成果,列举了若干化学工程在传递与过程强化、化工分离过程、精细与药物化工、能源化工和材料化工领域从基础研究到工业化应用的例子和成果,展望了化学工程学科今后发展的方向及目标.     

基于“教学评一体化”的化学探究活动一般思路方法建构*——以“物质的分离与提纯”复习课为例

针对学生面对化学实验探究问题无从下手的情况,以物质的分离与提纯这一类探究实验为例,通过“教学评一体化”的教学模式引导学生建立解决“物质分离与提纯”探究实验的一般思路方法。     

混合导体透氧膜反应器中水分解反应研究进展

混合导体透氧膜反应器可以将供氧反应、氧分离和耗氧反应耦合在一个单元,实现反应和分离一体化,简化化工过程.水分解反应参与的混合导体透氧膜反应器能够实现氢气的制备和分离,近年来受到越来越多的关注.这篇文章综述了混合导体透氧膜反应器中水分解反应领域的研究进展,总结了包括膜材料、催化剂、操作条件等对透氧膜反应器中水分解反应的影...     

农林院校化学工程与技术学科研究生创新能力培养的探讨

针对当前农林院校化学工程与技术学科研究生在创新方面存在的问题,根据学科特点,以提高研究生的创新能力为目标,提出:要探索化学工程与技术学科新型研究生招生模式;完善研究生创新课程体系,建立新型培养模式;更新教师的教育观念,创造适宜的教学环境;建立严格健全的考核和评价制度;加强导师队伍建设;建立多方位、多层面的研究生奖助体系;加强国际合作与交流,从而创建化学工程与技术学科研究生创新能力培养的新体系。     

科研成果转化为化学反应工程实验项目的应用研究

用生活废油催化裂解与变换重整制氢来替代现有的化学反应工程中一氧化碳变换重整制氢实验,替换后的整个实验从原料到产品都是学生一手完成。该实验绿色环保,且实验过程的完成可让学生了解从原料到产品的整个连续的化工生产过程,激发了学生的学习兴趣,在提高学生的动手能力以及从事科学研究的能力的同时,降低了实验耗费成本,提高了实验的安全性。     

科研助力教学打造自制化工教学仪器

The separation experiment project introduced in this paper had been used in undergraduate teaching since the spring of 2015.A patented spiral wound diffusion dialysis membrane module was used to design a set of teaching instrument.Parts of an onging National Natural Science Foundation research contents were applied in teaching.The chemical engineering laboratory teaching contents were continuously enriched by following the forefront of scientific research.     

Reaction-induced phase separation in polyethersulfone-modified epoxy-amine systems studied by temperature modulated differential scanning calorimetry

In epoxy-amine systems with a thermoplastic additive, the initially homogeneous reaction mixture can change into a multi-phase morphology as a result of the increase in molecular weight or network formation of the curing matrix. Temperature modulated DSC (TMDSC) allows the real-time monitoring of this reaction-induced phase separation. A linear polymerizing epoxy-amine (DGEBA–aniline) and a network-forming epoxy-amine (DGEBA–methylene dianiline), both with an amorphous engineering thermoplastic additive (polyethersulfone, PES), are used to illustrate the effects of phase separation on the signals of the TMDSC experiment. The non-reversing heat flow gives information about the reaction kinetics. The heat capacity signal also contains information about the reaction mechanism in combination with effects induced by the changing morphology and rheology such as phase separation and vitrification. In quasi-isothermal (partial cure) TMDSC experiments, the compositional changes resulting from the proceeding phase separation are shown by distinct stepwise heat capacity decreases. The heat flow phase signal is a sensitive indication of relaxation phenomena accompanying the effects of phase separation and vitrification. Non-isothermal (post-cure) TMDSC experiments provide additional real-time information on further reaction and phase separation, and on the effect of temperature on phase separation, giving support to an LCST phase diagram. They also allow measurement of the thermal properties of the in situ formed multi-phase materials.     

Hybrid process scheme for the synthesis of ethyl lactate: conceptual design and analysis

Hybrid processes have received increased attention in the field of chemical and biochemical engineering because of their ability to overcome certain obstacles related to thermodynamics of the separation task to be carried out. Usually, in a hybrid process two processes are coupled; either reaction with separation or two different separation processes. In the design of such hybrid systems, the performance of each constituent element has to be taken into account, while their optimisation must account for their interdependency. In this paper, the methodology presented by Mitkowski et al. (2009a) is applied to design and analyse a hybrid process scheme for the synthesis of ethyl lactate. Generated hybrid process schemes have been validated through computer-aided simulations.     

Kinetic Pattern Formation with Intermolecular Interactions:A Modified Brusselator Model

In this work,we modify the traditional Brusselator model to incorporate the intermolecular interactions,based on which a systematic study is performed on the pattern formation mediated by chemical reaction and phase separation.It is found that if the chemical reaction dominates,the pattern formation will be inhibited by the phase separation while if the phase separation dominates,the chemical reaction will prevent,under certain conditions,the domain size from growing which results in dissipative patterns other than macroscopic phase separations.     

Quantitative on-line high-resolution NMR spectroscopy in process engineering applications

In many technical processes, complex multicomponent mixtures have to be handled, for example, in reaction or separation equipment. High-resolution NMR spectroscopy is an excellent tool to study these mixtures and gain insight in their behavior in the processes. For on-line studies under process conditions, flow NMR probes can be used in a wide range of temperature and pressure. A major challenge in engineering applications of NMR spectroscopy is the need for quantitative evaluation. Flow rates, recovery times, and other parameters of the on-line NMR experiments have to be optimized for this purpose. Since it is generally prohibitive to use deuterated solvents in engineering applications, suitable techniques for field homogenization and solvent signal suppression are needed. Two examples for the application of on-line NMR spectroscopic experiments in process engineering are presented, studies on chemical equilibria and reaction kinetics of the technically important system formaldehyde-water-methanol and investigations on reactive gas absorption of CO(2) in aqueous solutions of monoethanolamine.     

原油中环烷酸的分离与分析方法研究进展

综述原油中环烷酸的分离与分析方法。分离方法包括化学反应分离、吸附分离以及利用某些金属氧化物或过渡金属盐络合物分离的方法等。分析方法主要叙述了质谱分析法。     

超临界二氧化碳参与的两相体系及其在有机合成反应中的应用

均相催化剂具有催化活性高、选择性好等优点, 但是产物难于纯化、催化剂不易回收等问题一直制约它的应用. 两相体系为这些问题的解决提供了一条新途径. 超临界二氧化碳参与的两相体系是使用超临界二氧化碳作流动相, 其它一些对环境友好的反应介质, 如: 水、离子液体、聚乙二醇等, 用于固定催化剂, 进行金属络合物催化的有机合成反应. 其显著特点是将反应与分离两步操作并于一个过程中完成, 即所谓“均相反应、非均相分离”过程, 实现均相催化过程的连续化. 综述了近几年来超临界二氧化碳促进的两相体系的研究进展, 并介绍其在有机合成反应中的应用.     

Effects of Reversible Chemical Reaction on Morphology and Domain Growth of Phase Separating Binary Mixtures with Viscosity Difference

Summary: The effects of a reversible chemical reaction on morphology and dynamics of phase separating binary mixtures with viscosity difference are studied by numerically solving modified time‐dependent Ginzburg‐Landau and Navier‐Stokes equations. Much more interesting morphologies are observed in the system due to the coupling of reversible chemical reaction and viscosity difference between two components. When the chemical reaction rate is relatively low, the impact of viscosity difference on morphologies is prominent, so that the resulting patterns are affected by both reversible chemical reaction and viscosity difference. However, increasing the chemical reaction rate weakens the impact of viscosity difference on morphologies. Similarly, increasing the chemical reaction rate also suppresses the effects of viscosity difference on domain growth dynamics, which is prominent at the early stage of phase separation when the chemical reaction rate is relatively low. For both cases with relatively low and high chemical reaction rates, the average domain size eventually attains an equilibrium value due to the competition between the mixing of reversible chemical reaction and demixing of phase separation.

Domain patterns of a critical system with ϕ_ini = 0, and Γ₁ = Γ₂ = 0.001.     

Chemicophysical surface treatment and the experimental demonstration of Schottky-Mott rules for metal/semiconductor heterostructure interfaces

Metal/semiconductor (MS) heterostructure is of wide interest in a number of areas including physics, chemistry, materials science, materials engineering, chemical engineering, and electrical engineering. It is an important element of modern technology. The present investigation describes a novel experimental technique to address the influence of interfacial chemical passivation on the Schottky-Mott [Naturwiss. 26, 843 (1938); Cambridge Philos. Soc. 34, 568 (1938)] rules for MS heterostructure, and to try to establish these rules. The success of the experiment derives from three remarkable findings: First, a semiconductor (Al(x)Ga(1-x)N), which is robust and relatively less susceptible to an easy reaction with foreign chemicals, is needed for the demonstration. Second, reactive ion etching together with wet chemical etching by certain selected chemical (such as KOH), but not by others (for example, H(3)PO(4) or aqua regia), can clean the semiconductor surface well, and remove/passivate the dangling chemical bonds from this surface. Third, a judicious selection of deposition parameters for the deposition of metal(s) preferably on a certain selected semiconductor can lead to metal deposition on the semiconductor surface by van der Waals type of epitaxy. Transmission electron microscopy and x-ray diffraction indicate that MS heterostructures, thus prepared, are very different from others; they appear to provide convincing experimental verification of the Schottky-Mott rules, and to establish these rules without any ambiguity. Others fail to do it.