Activated zeolite beta and its use for hydrocarbon conversion

A method of preparing an activated zeolite beta catalyst comprising the steps of:

• (a) calcining a crystalline microporous three-dimensional solid composition having the structure and composition of zeolite beta by heating in air or an inert atmosphere at a temperature and for a period of time sufficient to oxidize at least a substantial portion of a catalyst templating agent initially present on said composition to form a calcined catalyst, said temperature being in the range of from about 200.degree. to about 1000.degree. C. and said time being in excess of about 0.25 hours;
• and
• (b) ion-exchanging said calcined catalyst with a salt solution containing at least one hydrogen-forming cation selected from NH.sub.4.sup.+ and quaternary ammonium to form an initial catalyst;
• and
• (c) heating said catalyst in air or an inert atmosphere at an initial temperature effective to form an initial concentration of weak acid species comprising hydroxoaluminum cations and strong acid species comprising hydronium cations and continuing said heating at an activation temperature effective to substantially reduce the concentration of hydronium cations without substantially reducing the concentration of hydroxyaluminum cations to form the activated zeolite beta catalyst.