Vermiculite alkylammonium

There are several investigations of organic cations in clays in the literature, most of which originate from the soil research area. Many studies involving NMR were done by Mortland and coworkers [51]. A recent report involving alkylammonium cations in vermiculite and montmorillonite further depicts the kinds of interactions to expect when examining interlayer species 152]. C MAS spectra show that tetramethylammonium cations are able to reorient essentially isotropically in the clays, whereas the larger hexadecyltrimethylammonium is... 

McBride, M.B. and Mortland, M.M. (1973). Segregation and exchange properties of alkylammonium ions in a smectite and vermiculite. Clc s and Clay Minerals, 21 ... 

If H-vermiculite is immersed in neutral alkylamine, the corresponding alkylammonium-vermiculite is formed, although considerable amounts of Mg, Al, and other inorganic cations may also be present in the interlayer positions because of the instability of H-vermiculite (cf Section BIV5). Moreover, if an alkylammonium-vermiculite such as dodecylammonium is immersed in excess neutral alkylamine such as ethylamine, an interchange occurs within the lattice and ethylammonium-vermiculite, and free dodecylamine are produced (Walker and Bennett [1965]). 

Weiss [1963] has summarized the very extensive work of himself and his collaborators (Weiss and Hofmann [1951], Weiss et al. [1956, 1956a], Weiss [1958], Weiss et al. [1959]) on alkylammonium-vermiculite complexes. They find that the complexes are formed in simple stoichiometric proportions. Some estimate of the charge density of the silicate layers can be made from X-ray diffraction measurements of the interlayer distance of the pure n-alkyl-ammonium derivatives. Comparison is made with a variety of other minerals (silicates vanadates, phosphates, uranyl salts), which form similar organic complexes. Measurements have been made of the extra swelling produced when alkylammonium-silicates are treated with various liquids, viz., water and aqueous electrolyte solutions, alcohols, aldehydes, carboxylic acids, nitrocompounds, phenols, nitrogen bases, esters, ethers, ketones, halogen compounds, and hydrocarbons. 

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