Browsing by Author "Vansant, Etienne F"

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    Adsorption and Oxidation of Dimethylaniline by Laponite
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (11), 1977) Vansant, Etienne F; Yariv, Shmuel
    Coloration of synthetic Laponite by dimethylaniline was studied in relation to the adsorption data, and to different reaction conditions including the nature of the exchangeable cations, the pH and the concentration. Using visible and i.r. spectra, together with X-ray patterns, the colour reaction mechanism was investigated. The coloration could be ascribed to the following stages: (1) sorption of dimethyl-aniline, (2) oxidation by atmospheric oxygen into N,N-dimethyl-N′-methylbenzidine and bis-p(N,N-dimethylaminophenyl)-p(N′-methylaminophenyl)methane and (3) further oxidation to a blue quinoid cation or its protonated yellow component and to methyl violet, respectively.
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    Adsorption of Binary Gas Mixtures in Ion-exchanged Forms of Mordenite
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1981, 77 (06), 1981) Vansant, Etienne F; Voets, Raf
    Pure-component adsorption isotherms of CO, CO2, N2 and CH4 and multicomponent isotherms of CO + CO2, CO2+ N2 and CO2+ CH4 on mordenite were measured at 273, 258 and 243 K. No evidence of enhanced sorption of one component over the other was found. Adsorption of gas mixtures on different exchanged mordenites reveals that the separation ability increases with increasing electrostatic field in the adsorption cavities. The effect of the nature of the entering gas molecules on the separation is explained by the cationic and non-cationic specific character of the adsorption process. The temperature sensitivity and selectivity of the individual components influence the extent of the competition so that the separation increases significantly with decreasing adsorption temperature. The highest separation of gas mixtures into their pure components was observed at low adsorption temperatures, low percentages of CO2 in the residual gas phase and at high total equilibrium pressures.
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    Exchange of Alkylammonium Ions in the Zeolite-L
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (10), 1977) Vansant, Etienne F; Peeters, Guido
    A study has been made of the ion-exchange equilibria of NH+4, CH3NH+3, C2H5NH+3, n-C3H7NH+3, n-C4H9NH+3, (CH3)2NH+2, (CH3)3NH+, (C2H5)2NH+2 and (C2H5)3NH+ by the zeolite L. None of the alkylammonium ions could effect a complete replacement of the cations initially present in the zeolite. The maximum extent of exchange and the standard free energy of exchange were related to the molecular weight of the entering alkylammonium ions. It is suggested that there was an equilibrium distribution of the exchangeable cations over the different sites (C and D), governed by the nature and affinity of the entering alkylammonium ion and the cation initially present in the zeolite.