CATALYTIC ACTIVITY AND MOLECULAR-SIEVE PROPERTIES OF HIGH-SILICA ZEOLITES IN CONVERSIONS OF C-8 ALKYLBENZENES

An investigation has been made of the catalytic properties of zeolites of the pentasil, mordenite and Y types with different compositions of the skeleton in the isomerization of o-xylene and the disproportionat ion of ethylbenzene. The extremal dependence of the isomerizing activi ty of zeolites on the Al content of an elementary cell has been found. It has been shown that the ratio of the rates of disproportionation a nd isomerization of o-xylene decreases as the pore diameter of the zeo lites decreases. Quantitative data have been obtained on the para-sele ctivity of zeolites of the pentasil family in the reactions studied an d a scheme of conversion of C-8 alkylbenzenes is proposed, based on th e determining role of configurational diffusion of reactants in the ch annels of pentasils.