Hydrogen physicochemical characterization

In this work, the effect of the activation temperature upon the kinetic behaviour of the catalyst has been studied The physicochemical characterization has been carried out by XPS and TPR, and the variation of the surface properties has been related to the observed hydrogenation and coke formation kinetics. 

Palladium, rhodium and ruthenium complexes of the Schiff base salen are synthesized in the supercages of zeolite Y. The existence of intracrystalline transition metal-salen complexes is verified by a detailed physicochemical characterization. The catalytic properties of the prepared host/guest inclusion compounds are explored in the hydrogenation of hexene-(l) or an equimolar mixture of hexene-(l) and 2,4,4-trimethylpentene-(l). 

A novel titanium containing zeolite mordenite has been synthesized hydrothermally using 1,4 diaza bicyclo 2,2,2 octane (DABCO) as a templating agent for the first time. Physicochemical characterization of the sample showed that Ti atoms are part of the framework, probably in tetrahedral co-ordination. These zeolites have been found to be active catalysts in phenol hydroxylation with hydrogen peroxide as an oxidant. 

Singh S.P., Singh R.N., Poillearat G., Chartier P., Physicochemical and electrochemical characterization of active films of LaNiOg for use as anode in alkaline water electrolysis, Int. J. Hydrogen Energ., 20(3), 203-210,1995. 

For the rational design of transition metal catalyzed reactions, as well as for fine-tuning, it is vital to know about the catalytic mechanism in as much detail as possible. Apart from kinetic measurements, the only way to learn about mechanistic details is direct spectroscopic observation of reactive intermediates. In this chapter, we have demonstrated that NMR spectroscopy is an invaluable tool in this respect. In combination with other physicochemical effects (such as parahydrogen induced nuclear polarization) even reactive intermediates, which are present at only very low concentrations, can be observed and fully characterized. Therefore, it might be worthwhile not only to apply standard experiments, but to go and exploit some of the more exotic techniques that are now available and ready to use. The successful story of homogeneous hydrogenation with rhodium catalysts demonstrates impressively that this really might be worth the effort. 

Abstract NMR spectroscopy is so far the only analytical technique that has been used to get a detailed structural characterization of hydrogenated fullerenes. A substantial amount of information derived from different NMR experiments can thus be found in the literature for a number of fullerenes hydrogenated to various degrees. These studies have benefitted from the fact that chemical shifts of II and 13C and in some cases also 3He can be used to obtain structural information of these compounds. Such results, together with discussions about different NMR experiments and general considerations regarding sample preparations, are summarized in this chapter. The unique information, both structural and physicochemical, that can be derived from different NMR experiments ensures that this technique will continue to be of central importance in characterization of hydrogenated fullerenes. 

Physicochemical Interactions between permeating molecules and the macromolecules which comprise the membrane structure are considered. Dispersive, polar and hydrogen-bonding Interactions are used to establish an Index which can be useful In membrane material selection. A number of material characterization and evaluation procedures are outlined. 

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