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Stellenbosch University

1. Rose, Jamey. Hydroxylation of 2-methylnaphthalene to 2-methylnaphthoquinone over TI-substituted catalysis.

Degree: Process Engineering, 2010, Stellenbosch University

Thesis (MScEng (Process Engineering)) – University of Stellenbosch, 2010.

ENGLISH ABSTRACT: Partially oxygenated aromatic compounds, e.g. quinones, hydroquinones and cresols, play a vital role in the fine chemical industry and were initially prepared by stoichiometric oxidation processes that produce toxic products that are hazardous towards the environment. As a result, it was important to investigate environmentally friendly processes for the hydroxylation of aromatic compounds. This resulted in newer methods using Ti-substituted microporous zeolites as catalysts with hydrogen peroxide as oxidant in the presence of a solvent. However, the methods were found to be ineffective for large, bulky substrates due to the small pore structure. This led to using Ti-mesoporous materials as catalysts but suffered from two drawbacks; the hydrophilic nature and low hydrothermal stability of the catalyst structure. Ti-microporous and Ti-mesoporous materials acting as catalysts for the oxidation of bulky substrates achieved environmentally friendly processes but obtained low conversions and quinone yields. Therefore, the challenge has been to develop a process that is environmentally friendly, achieves high conversions, where the catalyst acts truly heterogeneous and obtains high quinone yields for the hydroxylation of bulky substrates. Recently, micropores/mesopores catalysts incorporating advantages of both micropores and mesopores materials were synthesised and seemed promising for the hydroxylation of bulky substrates. This study focuses on synthesising and evaluating the feasibility of various Ti-substituted catalysts for improving the hydroxylation of the bulky substrate, 2-methylnaphthalene (2MN) with hydrogen peroxide as oxidant in the presence of a solvent, acetonitrile. The oxidation of 2MN produces 2-methyl-1,4-naphthoquinone (2MNQ). 2MNQ is also known as menadione or Vitamin K3 and acts as a blood coagulating agent. The catalysts synthesised for this study were mesoporous catalysts, Ti- MCM-41 and Ti-MMM-2 and microporous/mesoporous catalysts, Ti-MMM-2(P123) and a highly ordered mesoporous material. The main objective of this study was to design an efficient process that is environmentally friendly and achieves high 2MN conversions and 2MNQ yields. This was achieved by evaluating the various catalysts synthesised, reaction conditions, testing if the catalyst was truly heterogeneous and identifying the products formed from the process. The designed process was proved to be environmentally friendly because the system did not produce products that were harmful towards the environment. The products identified in this study were 2MNQ, 2-methyl-1-naphthol, 2-naphthaldehyde, 3-ethoxy-4-methoxybenzaldehyde and menadione epoxide. An investigation was conducted to determine which catalyst synthesised favoured this process by quantifying the effect reaction conditions have on the various catalysts. The reaction conditions were defined in terms of the hydrogen peroxide volume, catalyst amount, …

Advisors/Committee Members: Callanan, L. H., University of Stellenbosch. Faculty of Engineering. Dept. of Process Engineering..

Subjects/Keywords: Process engineering; Hydroxylation; Ti-Molecular sieve

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Rose, J. (2010). Hydroxylation of 2-methylnaphthalene to 2-methylnaphthoquinone over TI-substituted catalysis. (Thesis). Stellenbosch University. Retrieved from http://hdl.handle.net/10019.1/5192

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Rose, Jamey. “Hydroxylation of 2-methylnaphthalene to 2-methylnaphthoquinone over TI-substituted catalysis.” 2010. Thesis, Stellenbosch University. Accessed February 21, 2020. http://hdl.handle.net/10019.1/5192.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Rose, Jamey. “Hydroxylation of 2-methylnaphthalene to 2-methylnaphthoquinone over TI-substituted catalysis.” 2010. Web. 21 Feb 2020.

Vancouver:

Rose J. Hydroxylation of 2-methylnaphthalene to 2-methylnaphthoquinone over TI-substituted catalysis. [Internet] [Thesis]. Stellenbosch University; 2010. [cited 2020 Feb 21]. Available from: http://hdl.handle.net/10019.1/5192.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Rose J. Hydroxylation of 2-methylnaphthalene to 2-methylnaphthoquinone over TI-substituted catalysis. [Thesis]. Stellenbosch University; 2010. Available from: http://hdl.handle.net/10019.1/5192

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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