Kinetic modeling of selective hydrogenation of phenol to cyclohexanone by using nickel hydroxyapatite catalyst

Abstract

The selective hydrogenation of phenol to cyclohexanone is a process of significant industrial relevance, serving as a key step in the production of important chemical intermediates. This study focuses on the preparation of Ni/HAP catalysts and evaluating various kinetic models for the hydrogenation of phenol to cyclohexanone. The catalyst was evaluated under optimized reaction conditions: 200 °C temperature, 30 bar hydrogen pressure, and a 10 % catalyst concentration. The uniqueness of this research lies in its comprehensive experimental and kinetic modeling approach, bridging a critical gap in the literature regarding the detailed kinetic behaviour of phenol hydrogenation using a Ni/HAP catalyst. Kinetic modeling was performed using three approaches: the rate law model, the Eley-Rideal (ER) model, and the Langmuir-Hinshelwood-Hougen-Watson (LHHW) model, each providing unique insights into the reaction mechanism and surface interactions. The kinetic assessment showed a competitive dissociative LHHW with 2-site adsorption model Ⅳ as the best model to describe this system. This work delivers an in-depth comparative analysis of kinetic models, thus enhancing the understanding of reaction pathways and facilitating the design of more efficient catalytic processes for industrial applications.