Kinetic Study on the Dehydration of tert -Amyl Alcohol Catalyzed by Ion-Exchange Resin

Abstract

The kinetic behavior of the liquid-phase dehydration of tert-amyl alcohol catalyzed by an acidic cation-exchange resin was investigated in a batch stirred reactor under atmospheric pressure. By varying the stirring speed, catalyst particle size, catalyst loading, and reaction temperature, the effects of external liquid–solid mass transfer and intraparticle diffusion were eliminated, and intrinsic kinetic data were obtained within the temperature range of 311.15 to 317.15 K. On this basis, a pseudohomogeneous (PH) model and a Langmuir–Hinshelwood–Hougen–Watson (LHHW) model were established to fit the experimental data. The results indicated that the LHHW model provided a better fit than the PH model and could accurately describe the competitive adsorption behavior between the reactant and products on the catalyst surface during the reaction. Thermodynamic and kinetic analyses revealed that the dehydration reaction is an endothermic process, and increasing the temperature is favorable for the reaction. Furthermore, the product water adsorbs more strongly onto the acidic sites of the resin than tert-amyl alcohol does, which acts as a crucial factor limiting the reaction rate. FT-IR characterization results further demonstrated a strong interaction between tert-amyl alcohol and the acidic sites on the resin surface, whereas the adsorption of the olefin product was relatively weak, indicating that the reaction aligns more closely with the LHHW mechanism. The developed LHHW kinetic model effectively characterizes the intrinsic kinetics of tert-amyl alcohol dehydration catalyzed by the ion-exchange resin, providing a theoretical basis for related reactor design, process simulation, and process optimization.