QUANTITATIVE INFRARED-SPECTROSCOPIC STUDY OF APROTIC ACIDITY OF THE SURFACE OF NATURAL ALUMINOSILICATES

Infrared spectroscopy has been used in a study of the adsorption of be nzonitrile on the surface of a cation-exchange form of kaolinite. The integral absorption coefficients of the stretching vibration bands of benzonitrile both adsorbed in the molecular form and bonded with the e xchange cations were calculated. From these IR spectra, the relative c oncentration of the aprotic acid centers on the surface of the kaolini te was determined. From these studies it was possible to obtain quanti tative characteristics of the acidic properties of the kaolinite surfa ce and to establish their dependence on the nature of the exchange cat ions and the temperature of the preliminary vacuum heat-treatment of t he samples.