Characterization of MCM-41 with Immobilized Bi-functional SH/SO3H Layer
Résumé
A new approach for quantitative determination of -SH and -SO3H functional groups on MCM-41 silica with covalently immobilized mercaptopropyl groups is proposed. A set of MCM-41 type samples containing 1 mmol g(-1) of mercaptopropyl groups was oxidized with proportional quantities of hydrogen peroxide and subsequently characterized with different ratios of grafted mercaptopropyl and propylsulfonic acid groups. Data calculated from conductometric titration were correlated with the corresponding X-ray photoelectron spectra and exhibit a linear relationship of results for both techniques. The described method was applied to thiol-containing MCM-41 samples to reveal ambient oxidation of organo-silicas with immobilized thiol groups.