Nanozarah titanium-karbon terkurung dalam silika mesoliang sebagai mangkin untuk pengoksidaan stirena

Nano-sized metal for heterogeneous catalytic process has attracted the attention of many researchers due to its surface area and high efficiency in the liquidliquid phase reaction. For oxidation o f organic compounds with H2O2 as the oxidant, not only nano-sized catalysts are needed, but also the pr...

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Main Author:	Aini, Syamsi
Format:	Thesis
Language:	English
Published:	2015
Subjects:	QD Chemistry
Online Access:	http://eprints.utm.my/id/eprint/77948/1/SyamsiAiniPFS2015.pdf
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id	my-utm-ep.77948
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spelling	my-utm-ep.779482018-07-18T07:36:51Z Nanozarah titanium-karbon terkurung dalam silika mesoliang sebagai mangkin untuk pengoksidaan stirena 2015-01 Aini, Syamsi QD Chemistry Nano-sized metal for heterogeneous catalytic process has attracted the attention of many researchers due to its surface area and high efficiency in the liquidliquid phase reaction. For oxidation o f organic compounds with H2O2 as the oxidant, not only nano-sized catalysts are needed, but also the presence o f organic moiety at the surface o f metal active site, besides having the silica shell. Therefore, titanium nanoparticles that have covalent bonding with organic compounds (T i-C ) and with the silica shell are expected to increase stability and activity o f the Ti-C nanoparticles (Ti-C@ SiO2). In this study, the Ti-C nanoparticle was synthesized by the reduction method with three different organic groups i.e. phenyl, phenol and thiophenol. Meanwhile, the silica shells o f the Ti-phenyl, Ti-phenol, Ti-thiophenol surfaces were synthesized via hydrolysis of TEOS. The catalysts were characterized using various techniques such as FTIR, DR-UV-Vis, TGA, NMR, XRD, FESEM, TEM, adsorption-desorption o f nitrogen analysis (BET) and pore volume analysis. The existence of silica shell with its morphology and porosity confirmed by FESEM and BET showed the agglomeration of Ti-C in the silica shell with nearly spherical shape and in mesopore size range. The titanium metals with lattice spacings o f 2 .2 A and 1.8 A in Ti-phenyl@SiO2, Ti-phenol@SiO2and Ti-thiophenol@SiO2 nano particles have sizes in the range o f 3-5 nm, 3-10 nm, and 3-10 nm, respectively. Furthermore, the Ti-phenyl, Ti-phenyl@SiO2 and commercial anatase (TiO2) were applied as catalysts for the oxidation of alkenes such as 1 -dodecene, 1 -octene, and styrene. The results show that, Ti-phenyl@SiO2 was inactive for both 1-octene and 1 -dodecene oxidation. Ti-phenyl, Ti-phenol, and Ti-thiophenol show high catalytic activity for oxidation of styrene but cannot be reused. However, the Ti-phenyl@SiO2 shows high catalytic activity for styrene oxidation and can be reused with only ca. 10% decrease in conversion. The Ti-phenyl@SiO2 with Si/Ti mol ratio of 2 exhibits the highest catalytic performance for alkene oxidation, especially for styrene with 92% o f conversion and 99% of selectivity towards benzaldehyde. In addition, the Ti-phenol@SiO2(1) was the most active among the catalysts with 90% o f conversion and 99% o f selectivity towards benzaldehyde. Meanwhile, the Ti-thiophenol@SiO2(2 ) catalyst was the most active to produce benzaldehyde with the conversion of 80% and selectivity of 97%. The high catalytic activity shown by Ti-C@ SiO2 catalysts in the oxidation of styrene can be explained based on structural similarity of the phenyl group of Ti-phenyl@SiO2 catalysts with the styrene structure, and the easier access of the substrates to the Ti active sites due to the mesoporous silica shells. 2015-01 Thesis http://eprints.utm.my/id/eprint/77948/ http://eprints.utm.my/id/eprint/77948/1/SyamsiAiniPFS2015.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:96377 phd doctoral Universiti Teknologi Malaysia, Faculty of Science Faculty of Science
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	QD Chemistry
spellingShingle	QD Chemistry Aini, Syamsi Nanozarah titanium-karbon terkurung dalam silika mesoliang sebagai mangkin untuk pengoksidaan stirena
description	Nano-sized metal for heterogeneous catalytic process has attracted the attention of many researchers due to its surface area and high efficiency in the liquidliquid phase reaction. For oxidation o f organic compounds with H2O2 as the oxidant, not only nano-sized catalysts are needed, but also the presence o f organic moiety at the surface o f metal active site, besides having the silica shell. Therefore, titanium nanoparticles that have covalent bonding with organic compounds (T i-C ) and with the silica shell are expected to increase stability and activity o f the Ti-C nanoparticles (Ti-C@ SiO2). In this study, the Ti-C nanoparticle was synthesized by the reduction method with three different organic groups i.e. phenyl, phenol and thiophenol. Meanwhile, the silica shells o f the Ti-phenyl, Ti-phenol, Ti-thiophenol surfaces were synthesized via hydrolysis of TEOS. The catalysts were characterized using various techniques such as FTIR, DR-UV-Vis, TGA, NMR, XRD, FESEM, TEM, adsorption-desorption o f nitrogen analysis (BET) and pore volume analysis. The existence of silica shell with its morphology and porosity confirmed by FESEM and BET showed the agglomeration of Ti-C in the silica shell with nearly spherical shape and in mesopore size range. The titanium metals with lattice spacings o f 2 .2 A and 1.8 A in Ti-phenyl@SiO2, Ti-phenol@SiO2and Ti-thiophenol@SiO2 nano particles have sizes in the range o f 3-5 nm, 3-10 nm, and 3-10 nm, respectively. Furthermore, the Ti-phenyl, Ti-phenyl@SiO2 and commercial anatase (TiO2) were applied as catalysts for the oxidation of alkenes such as 1 -dodecene, 1 -octene, and styrene. The results show that, Ti-phenyl@SiO2 was inactive for both 1-octene and 1 -dodecene oxidation. Ti-phenyl, Ti-phenol, and Ti-thiophenol show high catalytic activity for oxidation of styrene but cannot be reused. However, the Ti-phenyl@SiO2 shows high catalytic activity for styrene oxidation and can be reused with only ca. 10% decrease in conversion. The Ti-phenyl@SiO2 with Si/Ti mol ratio of 2 exhibits the highest catalytic performance for alkene oxidation, especially for styrene with 92% o f conversion and 99% of selectivity towards benzaldehyde. In addition, the Ti-phenol@SiO2(1) was the most active among the catalysts with 90% o f conversion and 99% o f selectivity towards benzaldehyde. Meanwhile, the Ti-thiophenol@SiO2(2 ) catalyst was the most active to produce benzaldehyde with the conversion of 80% and selectivity of 97%. The high catalytic activity shown by Ti-C@ SiO2 catalysts in the oxidation of styrene can be explained based on structural similarity of the phenyl group of Ti-phenyl@SiO2 catalysts with the styrene structure, and the easier access of the substrates to the Ti active sites due to the mesoporous silica shells.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Aini, Syamsi
author_facet	Aini, Syamsi
author_sort	Aini, Syamsi
title	Nanozarah titanium-karbon terkurung dalam silika mesoliang sebagai mangkin untuk pengoksidaan stirena
title_short	Nanozarah titanium-karbon terkurung dalam silika mesoliang sebagai mangkin untuk pengoksidaan stirena
title_full	Nanozarah titanium-karbon terkurung dalam silika mesoliang sebagai mangkin untuk pengoksidaan stirena
title_fullStr	Nanozarah titanium-karbon terkurung dalam silika mesoliang sebagai mangkin untuk pengoksidaan stirena
title_full_unstemmed	Nanozarah titanium-karbon terkurung dalam silika mesoliang sebagai mangkin untuk pengoksidaan stirena
title_sort	nanozarah titanium-karbon terkurung dalam silika mesoliang sebagai mangkin untuk pengoksidaan stirena
granting_institution	Universiti Teknologi Malaysia, Faculty of Science
granting_department	Faculty of Science
publishDate	2015
url	http://eprints.utm.my/id/eprint/77948/1/SyamsiAiniPFS2015.pdf
_version_	1747817870095548416

Nanozarah titanium-karbon terkurung dalam silika mesoliang sebagai mangkin untuk pengoksidaan stirena

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