An investigation has been made of the properties of systems formed by zeolite NaY and alkali metal (Na, K, Ca) salts in the side-chain alkylation of toluene by methanol at 400-450-degrees-C and atmospheric pressure. It has been established that the introduction of carbonates of these metals (as opposed to salts, the anions of which are formed by P, Mo, N and Cl) into the zeolite by impregnation leads to catalytically active systems. Their adsorption properties and thermal characteristics indicate dispersion and stabilization of the salts in the zeolite structure. It is concluded that the nature of the cations and anions of the occluded salts affects the basicity of the modified zeolites, which, along with reducing the free volume of the zeolite cavities, has a considerable effect on the catalytic properties of the systems studied.