INVESTIGATION OF THE CATALYTIC PROPERTIES OF A TYPE Y-ZEOLITE MODIFIED WITH NH4 SALTS IN THE CONVERSION OF ISOBUTYLENE

In the conversion of isobutylene, a study has been made of the catalyt ic properties of zeolite-salt systems produced by the impregnation of Na, K and Rb forms of faujasite (SiO2/Al2O3 = 4.4) with aqueous soluti ons of NH4Cl, (NH4)2SO4, NaHSO4, (NH4)2HPO4 and H3BO3 with subsequent activation at 250 and 400-degrees-C. Modification of NaY makes it acti ve in the oligomerization of iso-C4H8 at 120-150-degrees-C. In the cas e of chloride and sulphate systems, isomerization and cracking of the oligomers formed also occur. The dependence of the carbenium ion activ ity of the catalysts studied on the strength of the acids forming the salts, their concentration, the nature of the zeolite cations and the activation temperature has been established. Variation of these parame ters makes it possible to control the activity and selectivity of zeol ite-salt systems in hydrocarbon conversions accelerated by acidic cata lysts.