High specific surface area metal fluorides as catalysts for the fluorination of 2-chloropyridine by HF

Authors:  Arnaud Astruc, Cindy Cochon, Samuel Dessources, Stéphane Célérier, Sylvette Brunet

Abstract:
The catalytic fluorination of 2-chloropyridine into 2-fluoropyridine by Cl/F exchange in presence of HF and a metal fluoride as catalyst was investigated. Crystallized metal fluorides (BaF₂, MgF₂, CaF₂, ZnF₂, LaF₃ and CeF₃) with significant specific surface area between 65 and 125 m² g⁻¹ were prepared by thermal decompositionof correspondingmetaltrifluoroacetates at 350^◦C undernitrogen. These solids were stable under fluorination operating conditions involved in the formation of 2-fluoropyridine. An important gain in activity for the catalytic fluorination of 2-chloropyridine was obtained with these metal fluorides compared to corresponding oxides used as catalyst. BaF₂ and MgF₂ were the most active catalysts for the fluorination of 2-chloropyridine. The higher activities are in relation with the weak or moderate strength of Lewis acidity of the active sites, measured by CO adsorption followed by IR spectroscopy

Keywords:
Fluoride metal catalyst
Trifluoroacetate metal fluoride
Fluorination
2-Chloropyridine
2-Fluoropyridine

Published in: Applied catalysis A: General  (Volume 453, Pages 1-402, 26 February 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

High specific surface area metal fluorides as catalysts for the fluorination of 2-chloropyridine by HF

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