Adsorption of olefins on aluminum- and aluminum/tetramethylammonium-exchanged bentonites

One montmorillonite, STx-1 (Texas, USA), was activated with different amounts of Al and tetramethylammonium (TMA+) cations to obtain materials with a combined Al3+ and TMA+ content equal to its cation exchange capacity. The adsorption capacity of these samples was studied saturating them with hept-1-ene at room temperature. The samples were heated and the evolved gases analyzed by Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry. Hept-1-ene reacted with the clays via proton transfer and resulted in the formation of a variety of reaction products (>60 hydrocarbons). In general, the presence of TMA+ cations significantly reduced the population of protons to selectively produce isomerization and hydration products.

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