Catalysis over activated high silica zeolites

A process for converting a feedstock comprising an alcohol, ether or mixture thereof to conversion product comprising hydrocarbons which comprises contacting said feedstock at conversion conditions with a catalyst composition comprising a supported crystalline zeolite having an initial silica-to-alumina mole ratio greater than 100 and the structure of zeolite ZSM-5 prepared by a method which comprises compositing said crystalline zeolite with a support matrix material of alumina, gallia or a combination thereof, calcining the resulting supported zeolite at a temperature of from about 200.degree. C. to about 600.degree. C. for a period of time ranging from about 1 minute to about 48 hours, contacting said calcined supported zeolite with volatile boron fluoride in a dry environment at a temperature of from about 0.degree. C. to about 100.degree. C. until said supported zeolite is saturated with said boron fluoride, purging unreacted boron fluoride from said boron fluoride contacted supported zeolite, hydrolyzing said boron fluoride contacted supported zeolite, and converting said hydrolyzed material to hydrogen form.