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 <SUP>1</SUP>H 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.

This thesis describes the work undertaken in order to improve the resolution of protein mixtures using ion exchange chromatography on cellulosic ion exchange materials. The thesis consists of two parts. The first part describes the modification of existing cellulosic material, in order to improve the physicochemical and chromatographic properties of the ion exchanger. This is done through the introduction to DCAY cellulose, an anion exchange material, of crosslinking agents of different length and also by the introduction to cellulose of a previously untried ion exchange group. The second part of the thesis describes a method of employing stepped Had elution gradients to give greatly improved protein resolution in bovine serum and human plasma samples on small and large columns of DIME cellulose. A method of pN/ionic strength gradient elution on CM cellulose is described using acetate and phosphate buffers for bovine aatum and human plasma chromatography and ionic strength gradient and pit gradient solution methods are described for the chromatography of milk whey proteins. A method of NAM gradient elution on CH cellulose is also described, which, when used in conjunction with the stepped elution gradient method greatly inproves the protein resolution of bovine serum, human plasma and milk whey samples. This method of elution is also applied to blood plasma samples from a person suffering from a blood disorder known an macroglobulinemia.

Throughout the 1990's several investigators have used a mechanistic theory based upon third order kinetics to explain the rates of the reactions of several substrates in aqueous mixtures of protic (e.g. methanol) an aprotic (e.g. acetone) solvents. Such substrates investigated have included <I>p</I>-nitrobenzoyl chloride and <I>p</I>-nitrobenzenesulfonyl chloride. Reactions of these substrates in aqueous alcohols yield two products; an acid (RCO<SUB>2</SUB>H and RSO<SUB>3</SUB>H) and an ester (RCO<SUB>2</SUB>R and RSO<SUB>3</SUB>R). Measurements of the relative amounts of the products obtained from these reactions has enabled investigators to calculate selectivity values, S (S = [Ester]/[Acid] x [Water]/[Alcohol]). Both the rates and products (selectivities) of these reactions have been successfully explained by this third order theory. This thesis (Chapters 1-5) is primarily concerned with testing the third order theory further by investigating the reactions of selected phosphoryl chlorides (e.g. diphenyl-chlorophosphate, (PhO)<SUB>2</SUB>POCl) in aqueous mixtures of protic and aprotic solvents. Some of the results obtained in this thesis strongly support the theory whilst some unexpected results have been explained by initial state solvation effects. Unexpected changes in selectivity in highly aqueous mixtures of methanol and ethanol (e.g. 10-30%) may be caused by complex solvent-solvent interactions in these solvents. Chapter six of this thesis is not concerned with the third order theory investigated in Chapters 1-5. Previous investigations of the solvolyses of <I>p</I>-methoxybenzoyl (anisoyl) chloride in aqueous methanol and ethanol have resulted in an S<SUB>N</SUB>1 type mechanism involving solvent separated ion pairs being postulated. Selectivities for these solvolyses are constant over the whole range of methanol-water and ethanol-water mixtures investigated (10-90%, % v/v) with the selectivity in ethanol being less than in methanol. These constant selectivities have provided an opportunity to investigate aqueous mixtures of other alcohols (e.g. propanols and butanols) and to discover whether effects such selective solvation of anisoyl chloride by alcohol occurs. Any changes in the pattern of selectivity might be due to such effects and not a change in mechanism because anisoyl chloride is reluctant to react via associative mechanisms even in solvents of low ionising power (e.g. ethanol).

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Selectivity data were obtained for solvolyses for <I>p</I>-nitrobenzoyl and <I>p</I>-nitrobenzenesulphonyl chlorides in aqueous methanol and ethanol at 25<SUP>o</SUP>C by HPLC analysis of the solvolysis mixtures. Kinetic data were also obtained for <I>p</I>-nitrobenzoyl chloride in aqueous methanol and ethanol mixtures and water. Selectivity data for <I>p</I>-nitrobenzenesulphonyl chloride was collected after one half life to limit decomposition of the ester product using a refrigerated HPLC system to avoid decomposition of <I>p</I>-nitrobenzenesulphonyl chloride to <I>p</I>-nitrobenzenesulphonic acid on the HPLC column. The experimental data was used to test two rate-product correlations derived from a third over kinetic model. Calculated and observed rate constants agreed well providing excellent support for the third order kinetic model. The second part of this thesis is a study of alkylation of 2-amino-6-methyl-5-oxo-4,5-dihydro-5-triazole-[1,5z]pyrimidine (known as precursor) to give the N-alkyl product 2-amino-6-methyl-5-oxo-4-(n-propyl)-4,5-dihydro-5-triazole-[1,5a]pyrimidine. The process was studied under a wide variety of conditions in the presence of tetrabutylammonium bromide with alkali metal bases in water, using propyl bromide as alkylating agent to maximise yield and study the reaction mechanism. Selectivity of benzyl bromide between precursor and hydroxide was used as a mechanistic probe to see if tetrabutylammonium bromide enhanced alkylation rates, and also as a mechanistic probe to study the reaction pathway. Other mechanistic probes were used to deduce if the reaction proceeded via a phase transfer pathway, or an aqueous homogeneous mechanism. The results showed that the process was aqueous homogeneous in nature.

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