贝克曼重排反应是己内酰胺合成中的关键反应步骤之一，具有副产硫酸铵多、能耗高和安全性差等问题。本文以实现贝克曼重排反应过程的微型化为目标，在液液体系混合、分散、传递和反应规律研究的基础上，针对液液微分散体系内重排过程的动力学、反应机理和有机催化重排等展开系统研究，为发展新型高效、绿色和安全的贝克曼重排新工艺和新装备提供基础。 为发展高性能微筛孔设备，针对液液均相混合过程，采用化学反应探针“Villermaux/Dushman”体系，系统研究了操作条件和微细结构对微筛孔反应器混合性能的影响规律，结合CFD模拟结果，建立了预测微尺度混合性能的数学模型，为微筛孔反应器的优化和设计提供了基础。针对液液非均相过程，研究了伴随传质、传热的微分散过程，揭示了传递与液液微分散过程的耦合规律。 建立了针对重排反应的微化工系统，将微化工设备与在线红外技术相结合，发展新型温度测量系统，探讨了微系统内分散和传质性能，测定了液液微分散体系中贝克曼重排反应动力学，并建立微尺度条件下重排反应数学模型。深入研究了重排反应机理，证明了SO3在反应中的催化作用，提出了SO3和己内酰胺之间存在络合平衡的新机理，得到了络合平衡常数及其数学模型。研究了温度和停留时间等因素对液液微尺度反应性能的影响规律，提出基于微化工系统的两段重排新工艺，新工艺的停留时间降低到10~40 s，酸肟比为0.8~2.0，相对于传统过程（停留时间15~180 min，酸肟比1.2~1.7）有了明显降低。提出了在绝热重排系统中加入气体扰动强化微尺度反应过程的新方法，新方法可有效减小液滴分散尺寸（20~44 μm），强化传质（强化因子1.5~3.8），加快反应速度（气体流速大于0.16 m/s），提供溶剂汽化空间，强化传热，提高过程的选择性和安全性。发展基于三氟乙酸的新型有机催化体系，建立有机催化重排反应的简化动力学模型，获得了各个温度和催化体系组成下的动力学参数。基于改进的有机催化体系，提出了一步法合成己内酰胺的新工艺，可避免肟化和重排反应间的分离纯化过程，实现了无副产硫酸铵，环己酮转化率达到100%，己内酰胺选择性大于99%。实现了有机酸催化贝克曼重排反应的微型化，重排反应速度比文献速度提高600倍以上，选择性从83~95%提高到99+%。
Beckmann rearrangement is an important step in the production of caprolactam. Several drawbacks are still exisiting in this process, such as a high by-production of ammonium sulfate, high energy cost and the safety problem. The goal of this work is to realize the Beckmann rearrangement in a microchemical system to overcome these drawbacks. The liquid-liquid mixing, dispersion, transfer and reaction performance in microscale size were first investigated and then the kinetics and mechanism of the Beckmann rearrangement, the organocatalyzed Beckmann rearrangement were carried out in the microchemical system. The work can provide a basis for developing the new process for Beckmann rearrangement, making the synthesis of caprolactam more efficient and safer.For the liquid-liquid mixing, the micromixing performances in the micro-sieve dispersion microreactor with different flow rates and geometric structures have been investigated by the Villermaux/Dushman parallel competing reaction. Based on the CFD simulation results, a mathematical model was developed to predict the mixing performance. For the liquid-liquid two-phase dispersion, the interaction between the transfer process and the liquid-liquid dispersion process was studied in a coaxial microchannel. A temperature measurement system combining a microreaction process with an infrared imaging technique was developed to measure the temperature profile and the reaction enthalpy of fast exothermic reaction. The kinetics and mechanism of Beckmann rearrangement of cyclohexanone oxime in oleum was investigated with a multiphase microchemical system, which could provide good dispersion ability and mass transfer performance. A mathematical model was developed to describe the kinetics. In addition, the role of SO3 as the catalyst was proved. An equilibrium mechanism model between SO3 and caprolactam was proposed and the equilibrium constant was determined. The model could be very helpful for the process design and optimization. The effects of temperature and residence time on the reaction performance were investigated in the microsystem and a new two-stage rearrangement technology was proposed. Compared with the traditional process, the new technology shows better performances. The residence time was decreased from 15~180 min to 10~40 s and the molar ratio of acid to oxime was decreased from 1.2~1.7 to 0.8~2.0. In addition, gas agitation was added into the adiabatic microsystem for the Beckmann rearrangement, which could decrease the disperse scale of the oleum to 20~44μm, enhance the mass and heat transfer, enhance the reaction rate (flow velocity＞0.16 m/s) and improve the selectivity and safety.A modified catalytic system based on trifluoroacetic acid was developed. A simplied kinetic model of the organocatalyzed Beckmann rearrangement was built to obtain the kinetics parameters at different temperatures and catalytic system compositions. A novel one-step synthesis from cyclohexanone to caprolactam was developed in the catalytic system, which could avoid the separation and purification between the ammoximation and rearrangement reaction and the large production of ammonium sulfate in both two steps. In addition, high conversion of cyclohexanone (100%) and high selectivity to caprolactam (99+%) could also be obtained in the novel process. Based on the results, the organocatalyzed Beckmann rearrangement was investigated in a microchemical system. The reaction rate was increased by 600 times and the selectivity was increased from 83~95% to 99+%.
