微通道反应器内Wittig-Horner 液液相转移催化反应过程强化及调控机制

The low reaction yield and selectivity of Wittig-Horner liquid-liquid phase transfer catalyzed reaction in conventional stirred reactors are partially resulted from inefficient interphase mass transfer. Microchannel reactor is thus employed to enhance the liquid-liquid mass transfer process in this proposal. In order to achieve synergism between interphase mass transfer and the intrinsic reaction kinetics, and hence the intensified result for the Wittig-Horner liquid-liquid phase transfer catalyzed reaction in the microchannel reactors, a combined experimental and numerical study is performed. Reaction kinetics of this two-phase reaction in the microchannel reactor is systematically investigated. The evolution mechanism from its intrinsic kinetics to apparent kinetics can be understood by examining the differences between the intrinsic kinetics and apparent kinetics and an in-depth analysis of the interactions among interphase mass transfer, intrinsic kinetics and apparent kinetics. As such, the process mechanism of this two-phase reaction can be revealed. A CFD model coupling two-phase flow, interphase mass transfer and intrinsic kinetics is developed and numerically solved, which is then adopted to simulate the experimental cases and beyond. The coupled numerical simulations are used to interpret the interactions among two-phase flow, interphase mass transfer and reactions, and to further reveal the quantitative regulation mechanism of Wittig-Horner liquid-liquid phase transfer catalyzed reaction. The project is expected to lay solid theoretical and technical foundations for the scientific design, improvement, optimization, operation and relevant industrial application development of liquid-liquid phase-transfer-catalyzed-reaction-oriented microchannel reactors.

针对导致传统釜式反应器中Wittig-Horner液液相转移催化反应的收率和选择性偏低的关键原因之一的相间传递限制问题，本项目采用微通道反应器强化液液传质过程，利用实验和数值模拟相结合的方法，瞄准如何实现传递与反应协同机制及过程强化的关键科学问题，系统研究微通道内Wittig-Horner液液相转移催化反应的动力学规律，通过对比本征反应动力学与表观反应动力学的差异和分析相间传质、本征反应动力学和表观反应动力学的相互作用关系，掌握该类型反应从本征动力学到表观动力学的演变规律，揭示反应的过程机理；建立基于 CFD 的两相流动-相间传质-反应过程耦合模型和数值模拟计算方法，利用耦合数值模拟，阐释两相流动-相间传质-反应过程三者间的耦合相互作用规律，揭示反应过程的定量调控机制，从而为面向液液相转移催化反应的微通道反应器的科学设计、优化改进、操作调控和相关工业应用开发奠定必要的理论和技术基础。

Wittig-Horner液液相转移催化反应是专一区域选择性和高立体选择性构建反式碳碳双键的重要单元反应，广泛应用于精细化学品的合成。其涉及不互溶有机相和水相两相体系，包括水相中的离子交换反应、有机相中的本体反应和离子对的相间传质，而相间传质直接影响反应速率和效果。目前，该类型反应主要在传统釜式反应器内进行，存在反应速率慢、时间长、放大困难、收率和选择性低等问题。原因之一是传统釜式反应器内比相界面积小、传质速率慢；原因之二是复杂非线性湍流和严重的流动不均匀性致使其液滴尺寸分布范围非常宽且难以精确控制，液滴间的相界面积相差很大，造成不同液滴的传质速率不同。对此，本项目采用微通道反应器强化液液相间传质，实验研究了操作参数等对该类型反应的特性影响规律，获得了相间传质和表观动力学的变化规律，揭示了该类型反应的时空过程机理；研究建立了微通道反应器内基于CFD的两相流动、相间传质和反应过程耦合数学模型和数值模拟计算方法，解决了耦合模拟计算的稳定性及收敛性问题，并通过将数值模拟结果与实验数据对比验证了耦合模型的准确性；在此基础之上，利用耦合数值模拟探究了微通道反应器内的局部流场细节信息，阐释了两相流动-相间传质-反应三者间的相互作用规律，揭示了该类型两相反应过程的定量调控机制，发展了两相反应定量调控的方法和策略；基于所获得的微尺度强化液液相间传质的深入认识，研究开发了在线萃取器和液液膜分离器，并构建了微反应—连续萃取—膜分离耦合，以及微反应—在线淬灭—膜分离耦合技术体系，拓展开发了多个涉及两相体系的微反应连续流合成工艺技术，为开发基于微通道反应器的液液相转移催化反应及相关两相反应的实际工业应用奠定了良好的理论和技术基础。