Acids and catalysis

This area also includes the introduction of additional catalytic sites in zeolites by organometallic precursor compounds. Both the adjustment of Brpnsted/Lewis acidity and the directed fixation of active transition metal centers inside zeolite cages and channels seem possible, but the size and structures of these precursors will be crucial. The molecular modification appears all the more important as many catalytic processes will remain heterogeneous in nature, especially when the shape-selectivity of sodalites, zeolites, pentasils, etc. is exploited. Once again, the possible versatility of organolanthanoid complexes deserves emphasis, since these metals verify to the above-mentioned acidity and catalysis effects [92]. 

Introduction Clay Structure, Surface Acidity, and Catalysis... 

Handbook of Layered Materials, ed. S.M. Auerbach, K.A. Carrado and P.K. Dutta, Marcel Dekker, Inc., New York, N.Y., 2004 R 196 K.A. Carrado, Introduction Clay Structure, Surface Acidity, and Catalysis , p. 1... 

It is not easy to see how the first of these criteria could be applied to two-phase catalysis. The rate of the catalysed reaction depends upon the volume of the resin phase (for constant chemical composition of the resin) and hence on the total amount of catalyst per unit volume of suspension, quite irrespective of mechanism and even when the catalyst is a strong acid and catalysis is simply due to the higher concentration of hydrogen ions in the resin phase. The second criterion is, in principle, applicable, as discussed in the next section, but is complicated by the lack of an entirely satisfactory quantitative theory of the dissociation of poly-acids [38, 48, 50]. It should be possible to make some use of the third criterion, based on the solvent change to deuterium oxide. 

---