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Effective dispersion of Au and Au-M (M = Co, Ni, Cu and Zn) bimetallic nanoparticles over TiO2 grafted SBA-15: their catalytic activity on dehydroisomerization of α-pinene
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. (Technical Chemistry)
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2013 (English)In: Microporous and Mesoporous Materials, ISSN 1387-1811, Vol. 173, 99-111 p.Article in journal (Refereed) Published
Abstract [en]

Mesostructured siliceous SBA-15 was synthesized via direct hydrothermal crystallization from acidic solution of poly-(ethylene glycol)-block-poly(propylene glycol)-block poly(ethylene glycol)-copolymer and tetraethyl orthosilicate. The amorphous surface of the calcined Si-SBA-15 was modified with 20wt.% of TiO2 by chemical grafting method using titanium isopropoxide as the titanium source in ethanol solution. Various metal nanoparticles Au, Au-M (M = Co, Ni, Cu and Zn) were supported on TiO2/SBA-15 by deposition-precipitation method (DP) using urea as the precipitating agent. The structural features of the synthesized materials were characterized by various physico-chemical techniques such as X-ray diffraction, nitrogen sorption, XPS and HR-TEM. BET results of Si-SBA-15 revealed the formation of mesoporous structure with an average pore size of 5.9nm, pore volume of 1.12 cm3/g and the specific surface area of 846 m2/g. HR-TEM results demonstrated that metal nanoparticles were highly dispersed over TiO2/SBA-15 and long range ordering of hexagonal mesopores of Si-SBA-15 was well retained after loading of 20 wt.% TiO2 and 3 wt.% of bimetallic nanoparticles. The catalytic performances of the prepared catalysts were studied on dehydroisomerization of α-pinene under gas phase conditions using hydrogen atmosphere. The stability and catalytic activity of Au-M-TiO2/SBA-15 (DP) catalysts upon conversion of α-pinene in to p-cymene was explored in comparison with the catalysts prepared by conventional method. AuNi-TiO2/SBA-15 catalysts prepared via DP method were found to be stable upon longer reaction time as well as superior in terms of conversion and selective towards the formation of p-cymene.

Place, publisher, year, edition, pages
Elsevier, 2013. Vol. 173, 99-111 p.
Keyword [en]
Supported bimetal catalysts, TiO2/SBA-15, Dehydroisomerization, α-Pinene, p-Cymene
National Category
Chemical Sciences
URN: urn:nbn:se:umu:diva-65772DOI: 10.1016/j.micromeso.2013.02.015OAI: diva2:604473
Available from: 2013-02-11 Created: 2013-02-11 Last updated: 2014-11-12Bibliographically approved
In thesis
1. Heterogeneously Catalyzed Valorization of Monoterpenes to High Value-Added Chemicals
Open this publication in new window or tab >>Heterogeneously Catalyzed Valorization of Monoterpenes to High Value-Added Chemicals
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Uppgradering av monoterpener till specialkemikalier med högt förädlingsvärde via heterogen katalys
Abstract [en]

A potential industrial process is profitable only if it is successfully implemented by the continuously developing chemical industry. Throughout last decades heterogeneous catalysis has opened doors to the creation of various know-how products which previously were considered unfeasible. Moreover, the use of heterogeneous catalysts allows improving existing processes to shift towards more ecological and cost efficient practices. In particular, polymer or fuel compounds could be eco-friendly produced from wood extractives, as an alternative to the conventional oil resources. This goal becomes even more attractive in light of the upcoming peak-oil.

In the Nordic pulping industry turpentine is widely available as a tonnage by-product. Despite its interesting properties and promising application possibilities this fraction is commonly burned in the recovery boilers for energy. Although the chemical composition of turpentine depends strongly on the specific pulping process, α-pinene is the predominant compound and as such most studied. The general message of this thesis is the successful implementation of the heterogeneous catalysts in one-pot value-added upgrading of crude turpentine and specific terpenes, particularly α-pinene. Concepts allowing the production of fragrances, resins, plastics and pharmaceutical compounds are presented in the current study. Both commercial (Amberlyst 70) and self-prepared (Me/Al-SBA-15 or TiO2) catalysts were studied in several reactions including: acetoxylation, isomerization, dehydroisomerisation and oxidation. Both commercially purified α-pinene and crude thermo-mechanical turpentine were used as raw materials in the catalytic one-pot synthesis of value-added compounds.

The experiments were performed in both batch and continuous reactor systems depending on the studied reaction. Successful results were obtained in case of several reactions. As an example, upon acetoxylation of α-pinene valuable fragrances – α-terpinyl and bornyl acetates – were produced with yields of 35 and 40 wt-%, respectively. Furthermore, in the dehydroisomerisation reaction of α-pinene, a yield of around 80 wt-% of an important fragrance, solvent and plastics precursor, ρ-cymene, was obtained. In the last case, thermo-mechanical turpentine was also successfully utilized. Still, some α-pinene oxidation tests leading to α-pinene oxide and verbenone fragrances were also carried out. Upon this study, further oxidation of ρ-cymene lead to the formation of ρ-methyl-acetophenone, a product essential for perfumery, pharmaceutical and pesticide industry as well as a potent polymer precursor. In addition, isomerization reactions were performed. Additionally, the catalytic materials were thoroughly characterized and analyzed.

Place, publisher, year, edition, pages
Umeå: Umeå University, 2014. 57 p.
Catalysis, terpenes, alpha-pinene
National Category
Chemical Process Engineering
urn:nbn:se:umu:diva-96205 (URN)978-91-7601-153-9 (ISBN)
Public defence
2014-12-04, KBC-huset, Stora hörsalen, KB3B1, Umeå universitet, Umeå, 13:00 (English)
Available from: 2014-11-13 Created: 2014-11-12 Last updated: 2014-11-12Bibliographically approved

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Samikannu, AjaikumarGolets, MikhailLarsson, WilliamShchukarev, AndreyKordas, KrisztianMikkola, Jyri-Pekka
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