SELECTIVE ALKYLATION OF XYLENES BY ALCOHOLS ON ZEOLITE CATALYSTS

The peculiarities of catalytic performance of crystalline aluminosilic ates of different types and compositions (X, Y including dealuminated Y', mordenite, pentasil ZSM-5), as well as of amorphous aluminosilicat e catalyst in conversion of xylene + alcohol mixtures were studied. Ne w data were obtained for alkylation of o-xylene with tert-butyl alcoho l, concerning controlling the selectivity and stability of the zeolite catalysts in reactions proceeding with the participation of water, in cluding the water evolved during the reaction, in particular by contro lling the acidic properties and hydrophobycity of the zeolites. A cata lyst ensuring production of 1,2-dimethyl-4-tert-butylbenzene (DMTBB) w ith a 94% yield and selectivity of alcohol conversion to the target pr oduct of 94-97% was developed. The catalyst can be used as the basis f or a high-performance and environmentally safe method for the synthesi s of DMTBB. The catalysts developed can be also used for selective alk ylation of o-xylene by C-3-C-5 alcohols and for alkylation of m-xylene by tert-butyl alcohol.