Browsing by Author "Terrell, Robert J."

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    Infrared study of effects of sulphur-poisoning on the adsorption of carbon monoxide by nickel
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (04), 1977) Rochester, Colin H.; Terrell, Robert J.
    The effects of preadsorbed hydrogen sulphide, n-propyl mercaptan, dimethyl sulphide, thiophene and carbonyl sulphide on the adsorption of carbon monoxide by silica supported nickel have been compared by study of the infrared spectra of adsorbed carbonyl species. The formation of bridged or multicentre bonded surface carbonyl species was irreversibly poisoned by all five sulphur compounds. The strength of adsorption of carbon monoxide molecules which were linearly bonded to surface nickel atoms was weakened by sulphiding of the metal. On sulphided nickel the infrared spectra are interpreted in terms of the predominant mode of adsorption involving two and possibly three carbon monoxide molecules linearly bonded to single nickel atoms. The resulting surface species are considered to be intermediates in the formation of nickel tetracarbonyl.
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    Infrared study of the adsorption of sulphur compounds on silica and silica-supported nickel
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (04), 1977) Rochester, Colin H.; Terrell, Robert J.
    Hydrogen bonding interactions between isolated hydroxyl groups on silica and adsorbed hydrogen sulphide, n-propyl mercaptan, dimethyl sulphide and thiophene molecules have been detected by infrared spectroscopy. Chemisorption of n-propyl mercaptan and dimethyl sulphide on silica primarily involved reaction of adsorbate molecules with strained siloxane bridges in the oxide surface. Thiophene was slowly chemisorbed on silica to give surface species, infrared spectra of which showed no evidence for unsaturation. The formation of the species involved slow exchange of hydrogen atoms between thiophene molecules and surface hydroxyl groups. Adsorption of carbonyl sulphide on silica could not be detected by infrared spectroscopy. Infrared spectra of n-propyl mercaptan and thiophene on nickel/silica resembled the corresponding spectra for the adsorbates on silica alone. No infrared bands due to surface species formed from hydrogen sulphide or carbonyl sulphide on nickel were detected. Dimethyl sulphide was predominantly associatively chemisorbed on nickel although some dissociative adsorption to give species containing CH2 groups may also have taken place.