The kinetics of the Beckmann rearrangement of cyclohexanone oxime (CHO) catalyzed by trifluoroacetic anhydride (TFAA) and trifluoroacetic acid (TFA) is proposed in this work. The effects of experimental parameters on the reaction rate are studied in microreactors, including CHO concentration, TFAA concentration, temperature, and caprolactam (CPL) concentration. The reaction is verified as first-order and the reaction rate shows a linear relationship with TFAA concentration and decreases with the increasing of CPL concentration. The in-situ FTIR is adopted to study the reaction mechanism and quantitative equilibrium relationship of CPL with TFAA. Based on the experimental results, a reaction mechanism is proposed and a kinetics model is established, which is in good agreement with the experimental data. The TFAA/TFA catalytic system allows high conversion and reaction rate compared with other organic acids.

An efficient method for the Beckmann rearrangement of cyclohexanone oxime (CHO) catalyzed by trifluoroacetic anhydride (TFAA) is proposed in this work. The effects of experimental parameters on the reaction rate are studied, including CHO concentration, TFAA/CHO ratio, temperature, and CPL concentration. The reaction rate shows a linear relationship with TFAA/CHO ratio and reduces with the increasing of CPL concentration. Based on the experimental data and the study of in-situ FTIR, a reaction mechanism is proposed and the equilibrium relationship between CPL and TFAA is established. A rate constant model is developed and is in good agreement with the experimental results. The TFAA/TFA catalytic system allows high conversion and reaction rate compared with other organic acids.

The nitration of chlorobenzene with concentrated mixed acids is a fast and highly exothermic process, which suffers from considerable mass transfer resistance and poor heat transfer rates. The reaction kinetics has not been thoroughly reported before. In this work, a continuous-flow microreactor system and a homogeneous reaction condition were proposed to obtain accurate chlorobenzene nitration kinetics data at high mixed acid concentrations. A general model for predicting the observed reaction rate constants was established. With a new method for estimating the equilibria associated with HNO3 in aqueous sulfuric acid, the rate constants based on nitronium ion and activation energies were obtained. Compared with batch reactors, the continuous-flow microreactor system allows for a sufficient heat transfer efficiency and accurate residence time control, making it possible to study the reaction performance more quickly and sensitively. This work may provide a reliable reference for the kinetic study of similar processes.

2, 3-Epoxypropyl neodecanoate (EPDA) is an important synthon of eco-friendly coatings, and its preparation methods and the relevant reaction mechanisms remain to be further studied. In this work, the two-step preparation method of EPDA is investigated. Under the optimized process conditions in the acidolysis reaction, 99% conversion of neodecanoic acid and 91-93% effective utilization rate of epichlorohydrin could be realized. In the following ring-closure reaction, the two-step alkali treatment was applied, and it can significantly reduce the treatment time and improve the yield of EPDA by 3-5%. Besides, the mechanism of the acidolysis reaction catalyzed by tetramethylammonium chloride (TMAC) is proposed. The two chemical reaction pathways are put forward to explain the formation of side product dichloropropanol. Two effective ways to control the side reactions are suggested, including the control of temperature in the range of 70-90 oC and reducing the concentration of inorganic chlorine in the reaction system.  The article has been published on ACS, Industrial & Engineering Chemistry Research. Please refer to http://dx.doi.org/10.1021/acs.iecr.0c02906 for full text.