J. Tejero et al., SCOPE AND LIMITATIONS OF MECHANISTIC INFERENCES FROM KINETIC-STUDIES ON ACIDIC MACROPOROUS RESINS - THE MTBE LIQUID-PHASE SYNTHESIS CASE, Applied catalysis. A, General, 134(1), 1996, pp. 21-36
It has been hypothesized hitherto that the liquid-phase synthesis of M
TBE on ion-exchange resins proceeds quasi-homogeneously in excess meth
anol by an ionic mechanism whose rate-limiting step is the protonation
of the alkene, and quasi-heterogeneously at very low methanol content
likely by a concerted proton transfer involving adsorbed reactants. H
owever, recent knowledge of the reaction involving the effect of the n
on-ideality of the liquid phase on the kinetics of the reaction, and t
he inhibitor effect of MTBE on the reaction rate, in addition to new d
ata on byproducts formation, suggest that MTBE synthesis can be looked
at as a quasi-heterogeneous catalysis independently of the methanol c
ontent of the liquid phase. Moreover, a transition between a Eley-Ride
al mechanism and an Langmuir-Hinshelwood one can be assumed as the met
hanol concentration of the liquid phase decreases.