Reaction kinetics investigation of the selective oxidation of aqueous ethanol solutions with air over a Au/TiO2 catalyst

Authors: Pedram Aghaei, Rob J. Berger

Abstract:
The selective oxidation of aqueous ethanol solution with air over a powdered commercial 1 wt% Au/TiO₂ catalyst was investigated in stirred mini-autoclaves. The catalyst was characterized by various techniques including N₂ physisorption, XRD, ICP-OES, and TEM. Temperature, pressure, initial ethanol concentration, catalyst concentration, and reaction time were varied in order to successfully determine the parameters of a Langmuir–Hinshelwood–Hougen–Watson type reaction kinetics model, which was derived from the surface reactions. It is assumed that hydrogen abstraction by surface hydroxyl species is the rate-determining step. The model adequately describes the decreasing conversion at higher ethanol concentration and also the selectivities towards the products acetaldehyde, acetic acid, ethyl acetate, and CO₂. The moderate description of the conversion at 180–200^◦C can be improved by expanding the model with a second reaction route.

Keywords:
Aerobic oxidation of aqueous ethanol
Gold catalysts
Production of acetic acid
Reaction kinetics

Published in: Applied Catalysis B: Environmental (Volumes 132–133, Pages 1-552, 27 March 2013)

Publisher: Elsevier  

ISSN Information: 0926-3373

Reaction kinetics investigation of the selective oxidation of aqueous ethanol solutions with air over a Au/TiO2 catalyst

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