Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.752006
Title: The selective chlorination of phenols using novel thiapolymers as catalysts
Author: Williams, Des
Awarding Body: University of Wales, Swansea
Current Institution: Swansea University
Date of Award: 2006
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Abstract:
Extensive work on enhancing the regioselectivity of electrophilic aromatic substitution reactions has been conducted at the Centre for Clean Chemistry, University of Wales Swansea. As a continuation of that work, this project involves the development of regioselective methods for the chlorination of phenols. Previous results conducted at the Centre for Clean Chemistry have shown that polythiaalkanes behave as highly selective catalysts for the chlorination of phenols with sulfuryl chloride. The work reported in this thesis involves the syntheses of numerous novel thiapolymers, containing branched chains, cyclic aliphatic rings and aromatic rings. These novel polymeric materials were tested as catalysts for the chlorination of phenol, o-cresol, m-cresol and m-xylenol. The first chapter gives an extensive introduction to aspects of the selective chlorination of phenols and a brief introduction to green chemistry and polymer synthesis. The second chapter reports the development of synthetic routes to some novel branched thiaalkanes from secondary dibromides. The synthesised novel branched thiapolymers were shown to be, above all, excellent selective catalysts for the chlorination of m-xylenol. The third chapter reports the synthesis of branched polymers and cyclic tetrahydrothiopyrans from methyl substituted 1,5-dibromopentanes. The branched polymeric materials synthesised were shown to behave as mediocre catalysts for the chlorination of phenols. However, the cyclic sulfides synthesised were shown to be excellent selective catalyst for the chlorination of o-cresol and also good selective catalysts for the chlorination of phenol and w-cresol. The fourth chapter reports the syntheses of thiapolymers containing cyclic aliphatic and aromatic rings. The novel cyclic aliphatic containing thiapolymers proved to be very effective selective catalysts for the chlorination of phenols with excellent results for the chlorination of o-cresol, and good results for the chlorination of w-cresol and w-xylenol obtained. Some of the novel aromatic containing polymers were also shown to be selective catalysts for the chlorination of o-cresol.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.752006  DOI: Not available
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