P. Bharathi et al., Molecular modeling studies on zeolite catalysts for shape-selective electrophilic substitution: I acylation of 2-methoxynaphthalene, B CHEM S J, 72(10), 1999, pp. 2161-2167
The diffusion characteristics of acylated 2-methoxynaphthalene inside large
pore zeolites were investigated. The interaction of the three isomers with
full; siliceous zeolite lattices was studied by energy-minimization calcul
ations. The favorable adsorption sites and the orientation of the acylated
products of 2-methoxynaphthalene were analyzed in detail. Three large pore
zeolites having 12 m channels were selected: (i) mordenite with an elliptic
al 1-d channel, (ii) zeolite-L with a circular channel and 2-d cages, and (
iii) zeolite-beta with circular 3-d channel systems. It was observed that t
he shape selectivity properties of the zeolites could be profitably used to
produce 2-acyl-6-methoxynaphthalene. In the case of mordenite, the diffusi
on of all three isomers is facile, whereas in the case of zeolite-L, the di
ffusion of 1-acyl-7-methoxy-naphthalene is mere facile than 2-acyl-6-methox
ynaphthalene and 1-acyl-2-methoxynaphthalene. In the case of zeolite beta,
the energy barrier for the diffusion of 2-acyl-6-methoxynaphthalene is sign
ificantly smaller than those of the other two isomers. Thus zeolite-beta is
predicted to be a suitable catalyst for the shape-selective acylation of 2
-methoxynaphthalene to 2-acyl-6-methoxynaphthalene.