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The heterogeneous gas/solid enantioselective hydrogenation of methyl pyruvate over cinchonidine modified supported platinum catalysts (the Orito reaction) in a differential flow system was studied using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and capillary gas chromatography. The reaction was studied over a temperature range of room temperature to 160°C. The adsorption of methyl pyruvate on a Pt(111) single crystal was also studied using Reflection Adsorption Infrared Spectroscopy (RAIRS). DRIFTS spectra are presented showing that methyl pyruvate absorbs on Pt/alumina catalysts principally via the keto-carbonyl (T1 adsorption mode). At room temperature, methyl pyruvate adsorbs on the unmodified catalyst in a T1 mode with the keto-carbonyl forming a carbon-oxygen-metal bond (COM), with a slight preference for the <i>trans </i>conformer. Over the modified catalyst at room temperature, methyl pyruvate adsorbs with a strong preference for the T1-<i>cis</i>_COMmode. Other modes of adsorption are observed: a <i>cis </i>bidentate mode utilising both carbonyls; a <i>trans </i>mode using the keto-carbonyl and the ester oxygen; and T1 adsorption via the keto-carbonyl lone-pairs. As the temperature is increased, these additional modes increase in population. The unmodified reaction was found to be temperature independent over the range studied while the modified reaction showed changes in conversion and enantioselectivity. The deactivation of the modified reaction is discussed in terms of an enantiodirecting function of the modifier and a ligand accelerating function. The enantiodirection decreases above room temperature, while the rate-enhancing ligand acceleration is stable up to 100°C. Above 100°C, it is proposed that the modifier destructively hydrogenates producing non-volatile side-products that block the active catalyst sites. Possible side-reactions and products are also discussed. The implications of a successful gas/solid Orito reaction are discussed with reference to current literature.

This study concerns the alkali promotion of Cu/ZnO/Al<SUB>2</SUB>O<SUB>3</SUB> catalysts which are used for the low temperature water-gas shift reaction. Preliminary high pressure microreactor studies revealed that, on addition of the promoter, an enhanced selectivity to the desired products was achieved rather than for by-product methanol formation. Diffuse Reflectance Infra-red Fourier Transform Spectroscopy (DRIFTS) has been employed during adsorption and subsequent temperature programmed desorption (TPD) and temperature programmed reaction (TPR) experiments in order to determine the mode of action of the promoter. The catalysts were prepared <I>via</I> a layered hydrotalcite-type precursor by co-precipitating the mixed metal nitrates with ammonium bicarbonate, thus generating the catalyst alkali free. Promotion was achieved by impregnation with alkali metal salts. Detailed carbon monoxide adsorption experiments have been used to explore the various parameters in the pre-treatment procedure and their effect on the resultant carbon monoxide stretching band. These studies have also allowed the presence of stepped copper planes to be identified following reduction of the sample, along with partially oxidised copper and a small amount of copper oxide. Catalysts promoted with potassium to different levels (0.02 to 1 weight %) were studied using carbon monoxide as a probe molecule, where the main observation was a sharp attenuation in the CO stretching frequency intensity and a site blocking mechanism of the promoter was invoked in explanation. No shift in the CO stretching frequency was observed. Another, more subtle, effect was identified for the support, bicarbonate formation on alumina was hindered while another surface species with a higher desorption temperature dominated. This was suggested as being a potassium-associated carbonate. Similarly, the effect on the support was seen in analogous carbon dioxide adsorption studies. In addition, the formation of CO following the exposure of the catalysts to CO<SUB>2</SUB> was found to increase on promotion, and, again, a potassium-associated species such as a carboxylate was invoked to explain this.

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The main objective of this research was to produce magnesium alkyl complexes which are active catalysts or procatalysts in the polymerisation of ethene. The nitrogen based ligands in the magnesium complexes were chosen because of the reported activity of similar transition metal diimine and aluminium alkyl amidinate catalysts. Three classes of compounds were investigated: 1) magnesium di-/tri-amine dialkyl complexes, 2) magnesium alkyl α-diimine complexes, and 3) magnesium alkyl bis(iminophosphorano)methanide complexes. Ethene polymerisation studies of these products were implemented and revealed that these compounds are inactive under both mild and forcing conditions.

<SUP>31</SUP>P NMR spectroscopy was used to investigate the mechanism and kinetics of the hydrolysis of the metal dithiophosphate class of lubricant additives. The homogeneous hydrolysis of zinc(II) bis (<I>O,O</I>-dialkyl dithiophosphates), [(RO)<SUB>2</SUB>PS<SUB>2</SUB>]<SUB>2</SUB>Zn, (ZDTPs), where R= ethyl, 2-propyl, 2-butyl, n-hexyl, 4-methyl-2-pentyl and 2-ethylhexyl, at 85°C in 1,2-dimethoxyethane solution proceeded to give phosphoric acid, <I>O</I>-alkyl thiophosphoric acid, <I>O,O</I>-dialkyl dithiophosphoric acid and <I>O</I>-alkyl phosphoric acid via the corresponding intermediary <I>O,O</I>-dialkyl dithiophosphoric acid and thiophosphoric acid. The rates of hydrolysis were found to be independent of the alkyl substituent and fall within the range k<SUB>obs</SUB>=(2.34-2.96)x10<SUP>-4</SUP>s<SUP>-1</SUP>. The null effect of the alkyl groups upon the rate of hydrolysis is attributed to hydrophobic interactions that leave the central zinc atom exposed to attack by water irrespective of their size. A comparative study of the hydrolysis of the related cadmium(II) and nickel(II) bis(<I>O,O</I>-diethyl dithiophosphates) CdDTP and NiDTP) showed that both give rise to hydrolysis products identical to those observed for ZDTPs. Diethyl CdDTP is hydrolysed at a comparable rate to diethyl ZDTP (k<SUB>obs</SUB>=2.28x10<SUP>-4</SUP>s<SUP>-1</SUP> <I>νs</I> 2.34x10<SUP>-4</SUP>s<SUP>-1</SUP>). Diethyl NiDTP on the other hand hydrolyses at a rate that is some one hundred-fold slower. These results are explained in terms of the respective metal-sulphur bond strengths which are 205kJmol<SUP>-1</SUP> and 208.5kJmol<SUP>-1</SUP> for Zn-S and Cd-S, but 344kJmol<SUP>-1</SUP> for the Ni-S bond. The stronger Ni-S bond also results in the observation of <SUP>31</SUP>P NMR resonances for two hydrated species of the NiDTP whose participation in the hydrolytic process had previously been the subject of speculation.

The work described in this Thesis is concerned with the preparation, characterisation and catalysis of a range of metal loaded Molecular Sieves and, in particular, gallium containing Zeolite and Zeotype materials. Commercially, the CYCLAR process transforms LPG to aromatics using a catalyst based on gallium and Zeolite ZSM-5. Methods for preparing both this catalyst and related materials employing alternative zeolite structures have been explored and the resulting catalysts studied for their activity in propane conversion. A range of zeolite molecular sieves and their gallium analogues, with the EUO and MFI framework structures, have been prepared. Attempts to prepare EUO materials with increased metal content yielded the intergrowth material NU-85. The basic physical properties of these materials have been characterised by a variety of techniques including X-ray powder diffraction (XRPD), thermal gravimetric analysis (tga), scanning electron microscopy (SEM), X-ray fluorescence (XRF), neutron activation analysis (NAA) and acidity determinations by ammonia temperature programmed desorption (TPD). X-ray photoelectron spectroscopy (XPS) has shown the isomorphous substitution of gallium into framework sites in these molecular sieves is not homogeneous, with the zeotype crystals having a gallium rich crust and a siliceous core. This technique has also shown the presence of partially reduced gallium species in discharged catalysts. In catalysis studies all materials exhibited hydrogenolysis, dehydrogenation, oligomerisation activity to varying degrees in addition to the aforementioned CYCLAR aromatisation. Although the commercial preparation displayed the highest activity for aromatisation several of the gallosilicate and gallium doped EU-1 catalysts showed a potentially useful high selectivity for propane dehydrogenation, albeit at low conversion.

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