For the alkylation of o-xylene by tert-butanol, new data have been obtained concerning the possibilities of controlling the selectivity and stability of zeolite catalysts, among other means by controlling their acidic properties and hydrophoby. A study has been made of features of the action of crystalline aluminosilicates of different types and compositions (X, Y, including dealuminized Y＇, mordenite, pentasil), amorphous aluminosilicate and zeolite-containing catalyst Tseokar-2 in the conversion of C6H4(CH3)2 + C4H9OH mixtures. A catalyst ensuring the production of 1,2-dimethyl-4-tert-butylbenzene (DMTBB) with a yield of up to 94% of the theoretical figure with a selectivity of alcohol conversion to target product of 94-97% has been developed. It can be used as the basis of a high-performance and ecologically clean method for synthesizing DMTBB - the initial substance for the production of a number of new, technically valuable products.