The Adsorption of Amines on Silicates. Distinction Protonic and Aprotonic Acids Sites

[摘要] The infrared spectra obtained in the region of 4000¡­1200 cm-1 has been measured for pyridine, tertiary butylamine, and ethylenediamine adsorbed on various cation-exchanged silicates at various degassing temperature. It was possible to distinguish between protonic and aprotonic acid sites of all cation-exchanged silicates which exhibited both Bronsted and Lewis acidity. The sodium form appeared to be the least reactive towards adsorbates. The relative ratio of the band intensities of tertiary butylamine was directly related to the polarizing power of exchanged cations. Ethylenediamine was less easily desorbed from silicate surface than tertiary butylamine due to the additional amino group to react with surface active site, and probably to form ether hydrogen bond with surface oxgen by liberating migrating proton besides the coordination bond with Lewis acid site and the formation of NH3+ species with Bronsted acid site.

[学科分类] 化学（综合）