New Differential Thermogravimetric Method Using Cyclohexylamine for Measuring the Concentration of Interlamellar Protons in Clay Catalysts
James A. Ballantine, Peter Graham, Ila Patel, J. Howard Purnell, Kevin J. Williams, John M. Thomas, 1985. "New Differential Thermogravimetric Method Using Cyclohexylamine for Measuring the Concentration of Interlamellar Protons in Clay Catalysts", Proceedings of the International Clay Conference Denver, 1985, Leonard G. Schultz, H. van Olphen, Frederick A. Mumpton
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A new method for the estimation of proton concentrations in montmorillonite catalysts was developed that makes use of the well-resolved thermal desorption of intercalated cyclohexylamine. The clay sample was emersed in liquid cyclohexylamine, dried, and its thermal desorption plotted by means of a thermal gravimetric balance fitted with differential thermal gravimetric analyzer (TGA-DTG). The differential thermogravimetric (DTG) desorption curves for this cyclohexylamine-adsorbed material had four distinct desorptive zones, one of which was assigned to the thermal desorption of intercalated cyclohexylammonium ions. The percentage weight loss corresponding to this region of the curve gave a measure of the concentration of cyclohexylammonium ions in the montmorillonite sample. This value was then expressed in terms of the concentration of protons in the clay available to cyclohexylamine. A comparison, for a series of Al13-exchanged and heat-treated montmorillonites, of these proton concentrations with the catalytic activities of the clays indicated that high proton concentration correlated with strong catalytic activity.
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Proceedings of the International Clay Conference Denver, 1985
The papers included in this proceedings volume are representative of the research on clays being conducted in all parts of the world at the time of publication. Many of the subjects treated are controversial, and although some ideas expressed may not necessarily represent the views of the editors, the referees, or the publisher, they deserve to be brought to the attention of the international clay community.