Festkörper-NMR, 129 Xe-NMR- und BET-Studien an adsorbierten benzoiden Verbindungen auf mesoporösen Materialien

This thesis presents proof of existing analogies of Xenon-NMR-Spectroscopy and BET-Physisorption as related to studies conducted on Solid-State-spectroscopic experiments of loaded silica for the first time. This study contributed to a deeper understanding of the adsorption of solid organic adsorptives on mesoporous materials presenting new aspects and perspectives for future studies. Solid-State-NMR-Spectroscopy enables the observation of the process how the silica is loaded with organic adsorptives through the appearance of adsorbed crystalline species. The introduction of the ball mill method as an adsorption technique can be used as a standardized method for the future. The important advantage is in the methods reproducibility of the results and variable adjustable parameters of adsorption. Many experiments showed the strong dependence of NMR-spectroscopic parameters on the silica and hexamethylbenzene (HMB) model systems against a great number of adsorption parameters. The result gave proof of the direct relation between organic adsorptive and silica. The aid of Xenon-NMR-Spectroscopy demonstrated the coalescence of signals from the adsorbed xenon species on silica 22 which was loaded with HMB. The amount of the free activation enthalpy was ∆G ≠ ≈ 50 kJ mol -1 . Furthermore, it show the dependence of the intensity of low field signal (adsorbed xenon) and high field signal (free xenon gas) to the mass ratio of silica and HMB. Investigations conducted on BET-Measurements of silica, which were loaded with HMB using the ball mill technique showed, increased content of organic adsorptives lead to a linear drop of the specific surface ultimately reaching the level of the silica monolayer. In the experiment, determining the capacity of the silica monolayer was - contrary to earlier attempts with the mortar treatment, successfully achieved without any problems. Furthermore for the first time a bridge between Solid-State-NMR-Measurements to BET-Physisorption data has been established.