Browsing by Author "Griffiths, David M."

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    Infra-red Study of Hydrogen-bonding Interactions at the Solid/Liquid Interface
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (1-6), 1974) Griffiths, David M.; Marshall, Kenneth; Rochester, Colin H.
    An infra-red cell is described which enables the measurement of spectra of adsorbed species and the surfaces of powdered solids at the solid/liquid interface. The hydrogen-bonding interactions of acetone, ether and pyridine, adsorbed from carbon tetrachloride solution, with surface hydroxyl groups on silica have been studied. The results are compared with those for the same interactions at the solid/vapour interface. A correlation is observed between the position of the infra-red band due to the OH-stretching vibration of surface hydroxyl groups hydrogen bonded to a series of substituted pyridines and the pTC values of the corresponding pyridinium ions.
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    Infrared Study of the Adsorption of Acetone on Rutile
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1978, 74 (02), 1978) Griffiths, David M.; Rochester, Colin H.
    The associative adsorption of acetone onto Lewis acidic Ti4+ ion sites on rutile is followed by the formation of a surface enolate complex which reacts with a further acetone molecule to give mesityl oxide. The enolate is also an intermediate in the exchange of hydrogen atoms between acetone and hydroxyl groups on rutile. The effects of dehydroxylation and dehydration of the rutile surface on the associative adsorption of acetone and on the formation of the enolate complex and mesityl oxide have been studied using infrared spectroscopy. The reversibility of the surface reactions has been established, in part by a study of the adsorption of mesityl oxide, which not only associatively adsorbs onto Ti4+ ion sites but also decomposes to enolate complex and coordinatively liganded acetone molecules. Reduction of rutile in hydrogen decreases the Lewis acidity of the oxide surface but promotes the formation of surface acetate ions by the chemisorption of acetone.