THE EFFECT OF THE INFLUENCE OF THE NATURE OF THE MODIFYING METAL ON THE CATALYTIC PROPERTIES OF HIGH-SILICA ZEOLITE ZSM IN THE ALKYLATION OF TOLUENE WITH ISOPROPANOL

Abstract

The influence of the nature of the modifying metal (Sc, Pr, Ho, La, Yb) on the catalytic properties of the ZSM zeolite in the alkylation of toluene with isopropanol was studied in the temperature range of 300-350°C in a flow-through installation of ideal elongation. It is shown that the unmodified zeolite exhibits low selectivity for isopropyltoluenes (IPT) and propyltoluenes (PT). In the temperature range of 300-350°C on the ZSM, the selectivity for IPT and RT is 54.9-56.7% and 29.2-30.0%, respectively. At 300°C, the content of 4-IPT in the IPT mixture is 43.2 %. The changes that occur as a result of the modification change the product selectivity of the catalyst. For all modified catalysts, an increase in IPT selectivity and a decrease in PT selectivity. The nature of the modifying metal significantly affects the selectivity for IPT and the selectivity for the formation of 4-IPT. Modification of the ZSM zeolite with praseodium and scandium leads to an increase in the IPT selectivity from 64.4% to 66.4%, respectively. On these samples, the content of 4-IPT in the IPT mixture increases to 66.7%. -71.7%. A higher selectivity for IPT (69.2-71.7%) is observed on samples modified with holmium, ytterbium and lanthanum. The maximum para-selectivity is achieved on a sample modified with lanthanum and is 72.8%. According to para-selectivity, the modified catalysts are arranged in the following order: La-ZSM > Ho-ZSM > Yb-ZSM > Sc-ZSM > Pr-ZSM formation of IPT (71.2-71.7%) and modified with lanthanum (5% La- ZSM).