Synthesis, Characterization and Catalytic Performance of H3SiW12O40/SiO2 Prepared by Sol-Gel Technique
The purpose of this work is to study the synthesis, characterization, and catalytic performance of two types of solid heteropoly acid catalysts, namely, silicotungstic acid bulk (STAB) and STA-silica sol-gel (STA-SG) compared with sulfuric acid. From the XPS analyses, there was a significant formati...
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doaj-7defe591715a4ded8a53f37cb1dabd4b2020-11-24T23:19:35ZengHindawi LimitedJournal of Nanotechnology1687-95031687-95112011-01-01201110.1155/2011/507692507692Synthesis, Characterization and Catalytic Performance of H3SiW12O40/SiO2 Prepared by Sol-Gel TechniqueW. N. R. W. Isahak0M. Ismail1N. M. Nordin2J. M. Jahim3M. A. Yarmo4Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, MalaysiaSchool of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, MalaysiaDepartment of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, MalaysiaSchool of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, MalaysiaDepartment of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, MalaysiaThe purpose of this work is to study the synthesis, characterization, and catalytic performance of two types of solid heteropoly acid catalysts, namely, silicotungstic acid bulk (STAB) and STA-silica sol-gel (STA-SG) compared with sulfuric acid. From the XPS analyses, there was a significant formation of W-O-Si, W-O-W, and Si-O-Si bonding in STA-SG compared to that in STAB. The main spectra of O1s (90.74%, 531.5 eV) followed by other O1s peak (9.26%, 532.8 eV) were due to the presence of W-O-W and W-O-Si bonds, respectively. The STA-SG catalyst was found to be the more environmentally benign solid acid catalyst for the esterification reaction between oleic acid and glycerol due to its lower toxicity supported by silica via sol-gel technique. In addition, the ease of separation for STA-SG catalyst was attributed to its insoluble state in the product phase. The esterification products were then analysed by FTIR and HPLC. Both the H2SO4 and the STAB gave high conversion of 100% and 98% but at a lower selectivity of GME with 81.6% and 89.9%, respectively. On the contrary, the STA-SG enabled a conversion of 94% but with a significantly higher GME selectivity of 95%, rendering it the more efficient solid acid catalyst.http://dx.doi.org/10.1155/2011/507692 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
W. N. R. W. Isahak M. Ismail N. M. Nordin J. M. Jahim M. A. Yarmo |
spellingShingle |
W. N. R. W. Isahak M. Ismail N. M. Nordin J. M. Jahim M. A. Yarmo Synthesis, Characterization and Catalytic Performance of H3SiW12O40/SiO2 Prepared by Sol-Gel Technique Journal of Nanotechnology |
author_facet |
W. N. R. W. Isahak M. Ismail N. M. Nordin J. M. Jahim M. A. Yarmo |
author_sort |
W. N. R. W. Isahak |
title |
Synthesis, Characterization and Catalytic Performance of H3SiW12O40/SiO2
Prepared by Sol-Gel Technique |
title_short |
Synthesis, Characterization and Catalytic Performance of H3SiW12O40/SiO2
Prepared by Sol-Gel Technique |
title_full |
Synthesis, Characterization and Catalytic Performance of H3SiW12O40/SiO2
Prepared by Sol-Gel Technique |
title_fullStr |
Synthesis, Characterization and Catalytic Performance of H3SiW12O40/SiO2
Prepared by Sol-Gel Technique |
title_full_unstemmed |
Synthesis, Characterization and Catalytic Performance of H3SiW12O40/SiO2
Prepared by Sol-Gel Technique |
title_sort |
synthesis, characterization and catalytic performance of h3siw12o40/sio2
prepared by sol-gel technique |
publisher |
Hindawi Limited |
series |
Journal of Nanotechnology |
issn |
1687-9503 1687-9511 |
publishDate |
2011-01-01 |
description |
The purpose of this work is to study the synthesis, characterization, and catalytic performance of two types of solid heteropoly acid catalysts, namely, silicotungstic acid bulk (STAB) and STA-silica sol-gel (STA-SG) compared with sulfuric acid. From the XPS analyses, there was a significant formation of W-O-Si, W-O-W, and Si-O-Si bonding in STA-SG compared to that in STAB. The main spectra of O1s (90.74%, 531.5 eV) followed by other O1s peak (9.26%, 532.8 eV) were due to the presence of W-O-W and W-O-Si bonds, respectively. The STA-SG catalyst was found to be the more environmentally benign solid acid catalyst for the esterification reaction between oleic acid and glycerol due to its lower toxicity supported by silica via sol-gel technique. In addition, the ease of separation for STA-SG catalyst was attributed to its insoluble state in the product phase. The esterification products were then analysed by FTIR and HPLC. Both the H2SO4 and the STAB gave high conversion of 100% and 98% but at a lower selectivity of GME with 81.6% and 89.9%, respectively. On the contrary, the STA-SG enabled a conversion of 94% but with a significantly higher GME selectivity of 95%, rendering it the more efficient solid acid catalyst. |
url |
http://dx.doi.org/10.1155/2011/507692 |
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