Toward high selectivity aniline synthesis catalysis at elevated temperatures

Morisse, C. G.A., McCullagh, A. M., Campbell, J. W., How, C., MacLaren, D. A. , Carr, R. H., Mitchell, C. J. and Lennon, D. (2021) Toward high selectivity aniline synthesis catalysis at elevated temperatures. Industrial and Engineering Chemistry Research, 60(49), pp. 17917-17927. (doi: 10.1021/acs.iecr.1c03695) (PMCID:PMC8802303)

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Abstract

In connection with an initiative to enhance heat recovery from the large-scale operation of a heterogeneously catalyzed nitrobenzene hydrogenation process to produce aniline, it is necessary to operate the process at elevated temperatures (>100 °C), a condition that can compromise aniline selectivity. Alumina-supported palladium catalysts are selected as candidate materials that can provide sustained aniline yields at elevated temperatures. Two Pd/Al2O3 catalysts are examined that possess comparable mean Pd particle sizes (∼5 nm) for different Pd loading: 5 wt % Pd/Al2O3 and 0.3 wt % Pd/Al2O3. The higher Pd loading sample represents a reference catalyst for which the Pd crystallite morphology has previously been established. The lower Pd loading technical catalyst more closely corresponds to industrial specifications. The morphology of the Pd crystallites of the 0.3 wt % Pd/Al2O3 sample is explored by means of temperature-programmed infrared spectroscopy of chemisorbed CO. Reaction testing over the range of 60–180 °C shows effectively complete nitrobenzene conversion for both catalysts but with distinction in their selectivity profiles. The low loading catalyst is favored as it maximizes aniline selectivity and avoids the formation of overhydrogenated products. A plot of aniline yield as a function of WHSV for the 0.3 wt % Pd/Al2O3 catalyst at 100 °C yields a “volcano” like curve, indicating aniline selectivity to be sensitive to residence time. These observations are brought together to provide an indication of an aniline synthesis catalyst specification suited to a unit operation equipped for enhanced heat transfer.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:How, Mr Colin and MacLaren, Dr Donald and Campbell, Mr James and Mccullagh, Miss Annelouise and Lennon, Professor David and Morisse, Mr Clement
Authors: Morisse, C. G.A., McCullagh, A. M., Campbell, J. W., How, C., MacLaren, D. A., Carr, R. H., Mitchell, C. J., and Lennon, D.
College/School:College of Science and Engineering > School of Chemistry
College of Science and Engineering > School of Physics and Astronomy
Journal Name:Industrial and Engineering Chemistry Research
Publisher:American Chemical Society
ISSN:0888-5885
ISSN (Online):1520-5045
Published Online:01 December 2021
Copyright Holders:Copyright © 2021 American Chemical Society
First Published:First published in Industrial and Engineering Chemistry Research 60(49) 17917-17927
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
305200DTP 2018-19 University of GlasgowMary Beth KneafseyEngineering and Physical Sciences Research Council (EPSRC)EP/R513222/1MVLS - Graduate School
172865EPSRC DTP 16/17 and 17/18Mary Beth KneafseyEngineering and Physical Sciences Research Council (EPSRC)EP/N509668/1Research and Innovation Services