Acidity-reactivity relationships in catalytic esterification over ammonium sulfate-derived sulfated zirconia

Rabee, Abdallah I.M., Mekhemer, Gamal A.H., Osatiashtiani, Amin, Isaacs, Mark A., Lee, Adam F., Wilson, Karen and Zaki, Mohamed I. (2017). Acidity-reactivity relationships in catalytic esterification over ammonium sulfate-derived sulfated zirconia. Catalysts, 7 (7),

Abstract

New insight was gained into the acidity-reactivity relationships of sulfated zirconia (SZ) catalysts prepared via (NH4)2SO4 impregnation of Zr(OH)4 for propanoic acid esterification with methanol. A family of systematically related SZs was characterized by bulk and surface analyses including XRD, XPS, TGA-MS, N2 porosimetry, temperature-programmed propylamine decomposition, and FTIR of adsorbed pyridine, as well as methylbutynol (MBOH) as a reactive probe molecule. Increasing surface sulfation induces a transition from amphoteric character for the parent zirconia and low S loadings <1.7 wt %, evidenced by MBOH conversion to 3-hydroxy-3-methyl-2-butanone, methylbutyne and acetone, with higher S loadings resulting in strong Brønsted-Lewis acid pairs upon completion of the sulfate monolayer, which favored MBOH conversion to prenal. Catalytic activity for propanoic acid esterification directly correlated with acid strength determined from propylamine decomposition, coincident with the formation of Brønsted-Lewis acid pairs identified by MBOH reactive titration. Monodispersed bisulfate species are likely responsible for superacidity at intermediate sulfur loadings.

Publication DOI: https://doi.org/10.3390/catal7070204
Dataset DOI: https://doi.org/10.17036/researchdata.aston.ac.uk.00000279
Divisions: Engineering & Applied Sciences
Engineering & Applied Sciences > Chemical engineering & applied chemistry
Engineering & Applied Sciences > European Bioenergy Research Institute (EBRI)
Additional Information: © 2017 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). Funding: Alexander von Humboldt foundation (Bonn); EPSRC (EP/K000616/2, EP/G007594/4, EP/G007594/2 and EP/K036548/2); Royal Society (Industry Fellowship).
Uncontrolled Keywords: esterification,IR,solid acid,sulfated zirconia,XPS,zirconia,Catalysis,Physical and Theoretical Chemistry
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
Published Date: 2017-07-05
Authors: Rabee, Abdallah I.M.
Mekhemer, Gamal A.H.
Osatiashtiani, Amin ( 0000-0003-1334-127X)
Isaacs, Mark A.
Lee, Adam F. ( 0000-0002-2153-1391)
Wilson, Karen ( 0000-0003-4873-708X)
Zaki, Mohamed I.

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