Acidity and Catalytic Properties of Pillared Montmorillonite and Beidellite
A. Schutz, D. Plee, F. Borg, P. Jacobs, G. Poncelet, J. J. Fripiat, 1985. "Acidity and Catalytic Properties of Pillared Montmorillonite and Beidellite", Proceedings of the International Clay Conference Denver, 1985, Leonard G. Schultz, H. van Olphen, Frederick A. Mumpton
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Montmorillonite and synthetic beidellite were pillared with hydroxy-Al-polymers, and the physicochemical properties and catalytic activities of the pillared products were characterized by several techniques. The basal 001 reflection of the pillared clays was found to be about 18 Å and to decrease slightly after calcination. Infrared spectra of pillared beidellite exhibited an OH-stretching band at 3440 cm−1, similar to that observed for H+-exchanged beidellite or for the calcined form of NH4-beidellite. These OH groups, which interact with pyridine to give pyridinium ions (Brönsted acidity), were formed by the proton attack of Si—O—Al linkages of the tetrahedral layer to form Si—OH … Al entities. Such a band was not evident in the pillared montomorillonite. In both pillared clays, Lewis acidity was also detected by pyridine adsorption and was generated by the aluminum pillars.
Hydroisomerization-hydrocracking of n-decane was performed in a continuous flow reactor at at-omospheric pressure. The catalytic activity and the distribution of the products were determined for the pillared beidellite and montmorillonite and compared with the same data obtained for noncrystalline silica-alumina, ultrastable zeolite Y, and zeolite H-ZSM-5. Pillared montmorillonites and beidellites showed substantially different catalytic activities. Pillared beidellites had an overall activity only slightly less than that of the zeolites. The clays behaved similarly to zeolite-based bifunctional catalysts; i.e., they displayed high selectivity for isomerization at high conversion and symmetrical distribution of the individual products. They appear to be promising dewaxing catalysts. The pillared montmorillonites were much less active than the pillared beidellites. The high activities and selectivities of the pillared beidellites are likely due to the presence of Si—OH acid sites exposed in the interlamellar space.
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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.