Light olefin selective oxygenate conversion process using cha framework type aluminosilicate

Abstract

The invention relates to a method for converting an oxygenated hydrocarbon feedstock into an olefin product comprising: (a) forming a CHA framework type aluminosilicate sieve catalyst made from a substantially fluoride-free synthesis mixture comprising silicon and aluminum sources, a slurry medium, and a template, wherein the sieve is substantially free from framework phosphorus and exhibits a Si/Al ratio from about 40-60; (b) optionally formulating the molecular sieve catalyst with an oxidized aluminum-containing precursor matrix material and a clay binder to form a molecular sieve catalyst composition; (c) activating the catalyst by removing/decomposing the template; and (d) contacting the activated catalyst with the feedstock under conditions sufficient to form an olefin product comprising ≧about 65% by weight, on a water-free basis, of ethylene and propylene and having an ethylene-to-propylene ratio ≧about 1.2. Ethylene- and propylene-containing polymers can be formed from the olefin product.