Emission Spectroscopic Evidence of Bronsted Acid Sites in a Calcinated Vycor Glass

摘要

The emission and excitation spectra of quinoline and 2,3-dichloroquinozaline embedded in a calcinated (600 C) porous Vycor glass and dissolved in fluid solutions were recorded at various temperatures. The spectral characteristics and phosphorescence lifetimes of adsorbates were observed to be identical to those in 0.5 N sulphonic acid solutions, indicating that H+ transferred from the surface to the N-heterocyclics. The strong surface-adsorbate interaction is further revealed by the dynamic study of adsorbates at 77 and 4.2K.