Abstract: An analytical method is described whereby the exchange of various organic cations for other organic cations on montmorillonite is determined. The exchange is followed by means of a Beckman DK-1 ultraviolet spectrometer.
It has been observed that organic cations from compounds such as primary, secondary, and tertiary amine salts and quaternary ammonium salts can be exchanged for one another on the natural cation exchange substance, montmorillonite. The exchange is carried out in isooctane to which a small amount of isopropyl alcohol has been added to aid in dispersion of the organic-clay complex. By choosing pairs of organic substances, of which one has strong absorbance in the ultraviolet and the other does not, the exchange can be followed quantitatively with the u.v. spectrometer.