Cu ( I I)-MONTMORILLONITE WITH ANIL INE: I. SUSPENSIONS WITH CONSTANT SOL ID:L IQUID RATIO

coloured complexes and polymerizes on Fe(III)- and Cu(II)-montmorillonite. As evidenced by the adsorption isotherms, and the coloration and spectroscopic (IR, ESR) characteristics of the organo-clay associations formed, the conditions under which these reactions take place and the mechanisms involved iffer according to the exchange cation. Fe(III) interacts with the zr electrons of the aromatic ring to give rise to radical cations or so-called type II complexes, provided the aniline concentration does not exceed 500 p.p.m. With Cu(II). an aniline concentration above 500 p.p.m, is required and the reaction occurs at the amine group, proceeding through coordination followed by free-radical formation. Fe(III)- and Cu(ID-saturated smectites have been reported to react under dehydrating conditions with several aromatic ompounds (benzene, toluene, anisole, thiopene...) in a similar manner: for a given compound either both or neither gave rise to so-called type II complexes (Pinnavaia et al., 1974). With aniline (ANL), however, the two exchange forms behaved ifferently. When equilibrated with a 0.02 M solution of ANL in chloroform, for example, Cu(II)-montmorillonite urned coiour rapidly to olive-green and then to blue-black; the Fe(III) analogue did not change colour although it exhibited a higher adsorptio