Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638680
Title: Further studies toward the development of an empirical solvation model
Author: Roberts, K.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1986
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Abstract:
Solvolytic rate data are obtained (mainly by conductimetric technique) for reactions of 1-adamantyl iodide, trinitrophenolate (picrate), heptafluorobutyrate, trifluoroacetate, and 2-adamantyl trifluoromethanesulphonate (triflate) and perchlorate in binary aqueous mixtures of ethanol, methanol, acetone, trifluoroethanol and hexafluoroisopropanol, and also for the iodide substrate in acetic and formic acids. Additional data for iodine catalyzed solvolyses of 1-adamantyl iodide are reported. Rate data are also obtained for solvolyses of 1-adamantyl halides utilising a micro-cell and for solvolyses of t-butyl-heptafluorobutyrate in several of the binary aqueous mixtures highlighted above. Solvent ionizing power scales are calculated for each of the leaving groups and correlated with existing ionizing power scales based on other leaving groups, results are discussed in terms of the varying solvent and leaving group effects in operation. Direct comparison between the solvatochromically derived Z scale is made with that of the iodide ionizing power scale, and several alternative approaches to the analysis of solvent effects on rates are discussed. Kinetic data for solvolyses of several methyl and para-toluene sulphonate derivates are also obtained (via 1H nmr and uv spectrophotometric techniques, respectively) in a wide range of aqueous sulphuric and hydrochloric acid media. Solvent nucleophilicity and solvent ionizing power parameters for tosylates, are calculated utilising established information acquired through solvolytic study of these substrates in aqueous alcoholic and related media. These are compared with existing Hammett function and activity data, and utilised to calculate solvolytic rate constants allowing direct comparison with observed. Lastly, molecular mechanics calculations of solvolytic reactivity at bridgehead carbon spanning 22 orders of magnitude are correlated with a revised and uniform experimental data set based on the tosylate leaving group.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.638680  DOI: Not available
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