Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638685
Title: Regioselective electrophilic aromatic substitution reactions of naphthalene over solids
Author: Roberts, S. D.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 2000
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Abstract:
Chapter 1 highlights the many advantages of heterogeneous inorganic solids as catalysts, and summarises the various microporous and mesoporous solids that have been employed as catalysts. The synthesis and characterisation of the mesoporous materials that were used in the study are described. Chapter 2 focuses on the nitration of naphthalene. An introduction to nitration is given, and the results of nitration over a range of solids are presented. Unusual dinitronaphthalene product ratios were achieved over Al-MCM-41. Reactions catalysed by heteropoly acid immobilised within the pores of mesoporous materials are also described. Chapters 3 to 6 focus upon the alkylation of naphthalene. Emphasis is placed upon the importance of 2,6-dialkylnaphthalenes (2,6-DAN) as intermediates for the production of high performance engineering plastics, and why there is still significant room for improvement in both 2,6-DAN yield and selectivity. A molecular modelling study of 2,6- and 2,7- di-tert-butylnaphthalene (DTBN) highlighted the potential for achieving selectivity for the 2,6-over the 2,7-isomer. Zeolite H-Mordenite (HM) was the most selective catalyst for 2,6-DTBN, but showed poor activity. Efforts to increase both the 2,6-DTBN yield and selectivity over HM focused upon varying the reaction time; temperature; pressure; solvent; amount of alkylating agent, solvent, and catalyst; Si/Al ratio of the catalyst; and mode of addition. Optimisation resulted in a 60% yield of 2,6-DTBN with a 2,6/2,7 ratio of over 50. tert-Butylation reactions were achieved using mainly tert-butanol as the alkylating agent. The identification of by-products in the tert-butylation reaction has been attempted. Alkylation with other alkylating agents has been attempted, but selectivity for 2,6-DAN was inferior to that achieved in the tert-butylation reaction using tert-butanol.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.638685  DOI: Not available
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