Supporting characterizations

Another traditional method used for polymer support characterization is elemental analysis. Its use as an accurate quantitative technique for monitoring solid-phase reactions has also been demonstrated [146]. Microanalysis can be extremely valuable if a solid-phase reaction results in the loss or introduction of a heteroatom (usually N, S, P or halogen). In addition, this method can be used for determination of the loading level of a functional group (e. g. usually calculated directly from the observed microanalytical data). For example, in many cases, the displacement of chloride from Merrifield resin has been used as a guide to determine the yield of the solid-phase reaction. 

In this chapter we shall focus on the synthesis and adsorption characteristics of a CMS, prepared by a co-condensation or sol-gel route following the S°I° (S°, a neutral amine 1°, a neutral inorganie preeursor) pathway [3,6]. Immobilization of some cobalt(III) oxo clusters on CMS support, characterization of the resultant supported materials, and the use of these Co(III)-CMS materials in eatalytie oxidation rmder enviromnentally friendly conditions are also described. Related results available in the published literatine are also included at appropriate places with a view to broadening the scope of oin discussion. 

Despite the shortcomings of these methods, they serve as the principle analytical tools for catalyst support characterization. 

Several determination methods of a porous texture can be used for characterizing the supports. Certain of these methods (i.e., scanning electron microscopy, mercury porosimetry) are described in other chapters of this book. We shall only report here the specific methods of support characterization. 

The AIF3 support, characterized by different allotropic phases, has a wide distribution of the pore radii. Incipient wetness impregnation method has allowed the introduetion on the support of chromium phases with amorphous or mierocrystalline structure. The N2 porosimetry has shown that these phases cover the surface of the support, determining a more homogeneous pore radius distribution of the catalytic material. 

C and at a pressure of about 30 bar. The catalyst used in the BenSat benzene saturation technology from UOP is based on an alumina support characterized by spherical particles, a surface area of about 160—200m g and an apparent bulk density of about 0.45—0.6. The concentration of platinum metal present on the catalyst may vary from 0.375 to 0.75 wt% (407,408). 

In the case of impregnated catalysts supported on aerogels or xerogels, due to the molecular size of the metal precursor, metal particles are located outside SiOj particles [16, 32]. Heinrichs et al. [32] found a correlation between the size of those metal particles and the pore size distribution of the aerogel or xerogel support metal particles are larger on supports characterized by larger pores. 

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