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

Abdallah I.M. Rabee; Gamal A.H. Mekhemer; Amin Osatiashtiani; Mark A. Isaacs; Adam F. Lee; Karen Wilson; Mohamed I. Zaki

doi:10.3390/catal7070204

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

Abdallah I.M. Rabee, Gamal A.H. Mekhemer, Amin Osatiashtiani, Mark A. Isaacs, Adam F. Lee, Karen Wilson^*, Mohamed I. Zaki

^*Corresponding author for this work

Research output: Contribution to journal › Special issue › peer-review

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.

Original language	English
Article number	204
Journal	Catalysts
Volume	7
Issue number	7
DOIs	https://doi.org/10.3390/catal7070204
Publication status	Published - 5 Jul 2017

Bibliographical note

© 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).

Keywords

esterification
IR
solid acid
sulfated zirconia
XPS
zirconia

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Acidity-reactivity relationships in catalytic esterification
© 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/).
Final published version, 1.97 MB

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@article{22bd4835015945eea1a7e239c4f19451,

title = "Acidity-reactivity relationships in catalytic esterification over ammonium sulfate-derived sulfated zirconia",

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 Br{\o}nsted-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 Br{\o}nsted-Lewis acid pairs identified by MBOH reactive titration. Monodispersed bisulfate species are likely responsible for superacidity at intermediate sulfur loadings.",

keywords = "esterification, IR, solid acid, sulfated zirconia, XPS, zirconia",

author = "Rabee, {Abdallah I.M.} and Mekhemer, {Gamal A.H.} and Amin Osatiashtiani and Isaacs, {Mark A.} and Lee, {Adam F.} and Karen Wilson and Zaki, {Mohamed I.}",

note = "{\textcopyright} 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).",

year = "2017",

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doi = "10.3390/catal7070204",

language = "English",

volume = "7",

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AU - Rabee, Abdallah I.M.

AU - Mekhemer, Gamal A.H.

AU - Osatiashtiani, Amin

AU - Isaacs, Mark A.

AU - Lee, Adam F.

AU - Wilson, Karen

AU - Zaki, Mohamed I.

N1 - © 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).

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N2 - 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.

AB - 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.

KW - esterification

KW - IR

KW - solid acid

KW - sulfated zirconia

KW - XPS

KW - zirconia

UR - http://www.mdpi.com/2073-4344/7/7/204

UR - http://doi.org/10.17036/researchdata.aston.ac.uk.00000279

UR - http://www.scopus.com/inward/record.url?scp=85021971687&partnerID=8YFLogxK

U2 - 10.3390/catal7070204

DO - 10.3390/catal7070204

M3 - Special issue

AN - SCOPUS:85021971687

SN - 2073-4344

VL - 7

JO - Catalysts

JF - Catalysts

IS - 7

M1 - 204

ER -

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

Abstract

Bibliographical note

Keywords

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