Temperature-programmed desorption mass spectrometry of butyloxysilyl groups on silica surfaces

Abstract The decomposition reactions of the alkoxide groups SiO(CH 2 ) 3 CH 3 on dispersed silica (Butosil) surfaces have been studied by temperature-programmed desorption mass spectrometry (TPD) and quantum chemical (AM1) methods. The rate constants were calculated on the basis of experimental data and by the RRKM theory. The potential energy surface profiles were found by adiabatic and dynamic reaction coordinate methods. The main desorption channel corresponds to the elimination of 1-butene above 600 K. The TPD data suggest that this reaction is of first order and that it can be viewed as “unimolecular”.