Abstract
Influence of rare-earth elements (La, Ho, Yb, Pr) on acidic,textural and catalytic properties of ZSM-5 high-silica zeolite in the reaction of toluene alkylation with isopropanol was studied in the temperature range of 250-350 ° C in a flow unit of ideal displacement. It revealed that the nature of rare earth metal in zeolites ZSM-5 plays a crucial role in its para-selectivity and catalytic activity. Maximum selectivity with respect to cymols is achieved on a Yb modified zeolite and is 70.5%. The highest para- selectivity is displayed by La modified zeolite to make up 72.4%. It found that rise in selectivity for cymol is due to decrease in concentration of strong acid centers, rise in proportion of acid centers of moderate strength, as well as changes in the porous structure of the zeolite due to its chemical modification.