Rabee, AIM;
Mekhemer, GAH;
Osatiashtiani, A;
Isaacs, MA;
Lee, AF;
Wilson, K;
Zaki, MI;
(2017)
Acidity-Reactivity Relationships in Catalytic Esterification over Ammonium Sulfate-Derived Sulfated Zirconia.
Catalysts
, 7
(7)
, Article 204. 10.3390/catal7070204.
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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.
| Type: | Article |
|---|---|
| Title: | Acidity-Reactivity Relationships in Catalytic Esterification over Ammonium Sulfate-Derived Sulfated Zirconia |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3390/catal7070204 |
| Publisher version: | https://doi.org/10.3390/catal7070204 |
| Language: | English |
| Additional information: | This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0). |
| Keywords: | Science & Technology, Physical Sciences, Chemistry, Physical, Chemistry, Zirconia, Sulfated Zirconia, Solid Acid, XPS, IR, Esterification, Promoted Metal-Oxides, Biodiesel Production, CO Adsorption, Surface, Sites, ZrO2, Methylbutynol, Isomerization, Dioxide, Transesterification |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10053282 |
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