Hydrogenation of benzonitrile over supported Pd catalysts: kinetic and mechanistic insight

McAllister, M. I., Boulho, C., Gilpin, L. F., McMillan, L., Brennan, C. and Lennon, D. (2019) Hydrogenation of benzonitrile over supported Pd catalysts: kinetic and mechanistic insight. Organic Process Research and Development, 23(5), pp. 977-989. (doi:10.1021/acs.oprd.9b00058)

McAllister, M. I., Boulho, C., Gilpin, L. F., McMillan, L., Brennan, C. and Lennon, D. (2019) Hydrogenation of benzonitrile over supported Pd catalysts: kinetic and mechanistic insight. Organic Process Research and Development, 23(5), pp. 977-989. (doi:10.1021/acs.oprd.9b00058)

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Abstract

The liquid phase hydrogenation of benzonitrile over a 5wt% Pd/C catalyst using a stirred autoclave is investigated. The reaction conforms to a consecutive reaction sequence: firstly benzonitrile is hydrogenated to produce benzylamine, which subsequently undergoes a hydrogenolysis step to form toluene. Benzonitrile hydrogenation obeys first order kinetics with an activation energy of 27.6 kJ mol−1. In contrast, the benzylamine hydrogenolysis stage obeys zero order kinetics and exhibits an activation energy of 80.1 kJ mol−1. A 1wt% Pd/Al2O3 catalyst is additionally examined, which is also seen to support hydrogenolysis activity alongside the hydrogenation pathway. Gas phase transmission infrared spectroscopic measurements of the hydrogenation of benzonitrile and benzylamine over the 1wt% Pd/Al2O3 catalyst utilising hydrogen and deuterium are undertaken, which enable reaction schemes incorporating adsorption geometries of intermediate adsorption complexes to be proposed.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Lennon, Professor David and McMillan, Mr Liam and Boulho, Dr Cedric and Gilpin, Miss Lauren and McAllister, Mairi
Authors: McAllister, M. I., Boulho, C., Gilpin, L. F., McMillan, L., Brennan, C., and Lennon, D.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Organic Process Research and Development
Publisher:American Chemical Society
ISSN:1083-6160
ISSN (Online):1520-586X
Published Online:27 March 2019
Copyright Holders:Copyright © 2019 American Chemical Society
First Published:First published in Organic Process Research and Development 23(5):977-989
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
466652EPSRC Doctoral Training Account (DTA) 2007-2011Mary GoodmanEngineering and Physical Sciences Research Council (EPSRC)EP/P503582/1VPO VICE PRINCIPAL RESEARCH & ENTERPRISE
584861EPSRC Doctoral Training Grant 2011-2015Mary Beth KneafseyEngineering and Physical Sciences Research Council (EPSRC)EP/J500434/1VPO VICE PRINCIPAL RESEARCH & ENTERPRISE
642131Doctoral Training Grant 2013 - 2017Mary Beth KneafseyEngineering and Physical Sciences Research Council (EPSRC)EP/L50497X/1R&I - RESEARCH STRATEGY & INNOVATION
701101EPSRC 2015 DTPMary Beth KneafseyEngineering and Physical Sciences Research Council (EPSRC)EP/M508056/1R&I - RESEARCH STRATEGY & INNOVATION