TRANSFER OF CONCEPTS FROM HOMOGENEOUS TO HETEROGENEOUS CATALYSIS, USEOF HAMMETT RELATIONSHIPS TO ASSESS REACTION-MECHANISMS AND NATURE OF ACTIVE-SITES IN REACTIONS CATALYZED BY SULFIDES, METALS, CLAYS AND ZEOLITES
A. Finiels et al., TRANSFER OF CONCEPTS FROM HOMOGENEOUS TO HETEROGENEOUS CATALYSIS, USEOF HAMMETT RELATIONSHIPS TO ASSESS REACTION-MECHANISMS AND NATURE OF ACTIVE-SITES IN REACTIONS CATALYZED BY SULFIDES, METALS, CLAYS AND ZEOLITES, Journal of molecular catalysis. A, Chemical, 107(1-3), 1996, pp. 385-391
The application of Hammett or Hammett-type relationships to a series o
f various reactions catalyzed by clays, zeolites, sulfides and metals
is reviewed in this paper. Such relationships are, of course, of great
interest for a better knowledge of the reaction mechanisms over solid
catalysts and on the nature of the active species, Among the differen
t data obtained in the laboratory over those catalytic systems, it app
ears that Hammett slope rho values for the acid-catalyzed reactions in
volving Bronsted species in the rate-determining step (hydration, hydr
olysis, isomerization, electrophilic aromatic substitution) are of the
same order of magnitude for both homogeneous and heterogeneous reacti
ons, whereas deviations are more frequently observed for reactions inv
olving hydrogen.