Characterization and catalytic reactivity of xerogel catalysts based on mesoporous zirconia doped with telluric acid prepared by sol–gel method: mechanistic study of acetic acid esterification with benzyl alcohol - Université de Lille Accéder directement au contenu
Article Dans Une Revue Journal of Sol-Gel Science and Technology Année : 2021

Characterization and catalytic reactivity of xerogel catalysts based on mesoporous zirconia doped with telluric acid prepared by sol–gel method: mechanistic study of acetic acid esterification with benzyl alcohol

Résumé

Our work is focused on the research of new zirconia doped telluric acid catalysts prepared with sol–gel method. Optimization of different preparation parameters of the catalyst, such as the HNO3 assisted synthesis, molar ratio nTe(OH)6/nZr, and calcination temperature, was studied. Catalysts were characterized by N2-physisorption at 77 K, X-ray diffraction, UV–Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), Electron Scanning Microscopy, and surface acidity titration. The catalytic activity was tested in the esterification reaction of benzyl alcohol with acetic acid. The addition of HNO3 in the gelling step greatly improves the acidity of the catalyst through the development of the texture. Doping of zirconia by telluric acid improves the acidity of the catalyst and the catalytic performance, but this improvement does not follow the increase in the quantity of the doping agent in the catalyst. However, calcination of the catalyst allows the development of tetragonal ZrO2 phase and causes a loss in acidity and consequently a decrease in catalytic activity. Kinetics and mechanism study indicates that the catalytic reaction is of first order and is by the Eley–Rideal mechanism in which the adsorbed acetic acid species react with benzyl alcohol in the fluid phase to form the corresponding ester. By the application of Eyring’s theory shows that the adsorption step is endothermic and that a fast associative mechanism occurs between the adsorbed species and the second reagent.

Domaines

Catalyse
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Dates et versions

hal-04438500 , version 1 (05-02-2024)

Identifiants

Citer

Wafa Ksila, Mohamed Kadri Younes, Abdelhamid Ghorbel, Alain Rives. Characterization and catalytic reactivity of xerogel catalysts based on mesoporous zirconia doped with telluric acid prepared by sol–gel method: mechanistic study of acetic acid esterification with benzyl alcohol. Journal of Sol-Gel Science and Technology, 2021, Journal of Sol-Gel Science and Technology, 99 (2), pp.376-390. ⟨10.1007/s10971-021-05580-4⟩. ⟨hal-04438500⟩
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