Reaction Characteristics and Kinetics of Allyl Chloride Epoxidation Catalyzed by Supported Titanium Silicalite-1 in a Fixed-Bed Reactor

Abstract

The direct epoxidation of allyl chloride (ALC) to produce epichlorohydrin as a green and sustainable production technology is gaining global attention due to the significant reduction in wastewater and residues compared to traditional methods. This study conducted epoxidation experiments of ALC in a fixed-bed reactor using a titanium silicalite-1 supported catalyst to reveal the catalytic characteristics and kinetics. The effects of the operating conditions on the reaction performance are studied using the single-factor variable method. The results indicate that decreasing the liquid hourly space velocity, increasing the temperature, solvent amount, and feed ratio influence the reaction rates of the main epoxidation reaction and the side ring-opening reaction, leading to the tendency of increasing hydrogen peroxide (HP) conversion and decreasing epichlorohydrin selectivity. The optimal HP conversion and epichlorohydrin selectivity reached 96.34% and 95.88%, respectively. Based on the Eley–Rideal and Langmuir–Hinshelwood mechanism, kinetic modeling of the surface reaction as a rate-controlling step is constructed. Under the condition of eliminating external and internal diffusion limitations, kinetic data reflecting the intrinsic catalytic reaction rate are measured. The predicted reaction rates based on the Eley–Rideal model with HP being adsorbed show good agreement with the experimental data and accurately describe the intrinsic kinetic behavior of ALC epoxidation. This work provides theoretical support for the design and optimization of reactors for the direct epoxidation of ALC, thereby promoting the development and application of environmentally friendly production processes.