Patent ID: 6838586

Claim:
A method for converting an oxygenate to an olefin, said method comprising the following steps: providing a source of a silicon-containing composition; providing a source of an aluminum-containing composition; providing a source of a phosphorous-containing composition; providing a template; forming a reaction mixture sufficient to form a SAPO molecular sieve from said source of a silicon-containing composition, said source of an aluminum-containing composition, said source of phosphorous-containing composition, and said template, said reaction mixture having a first pH; determining a pH increase in said reaction mixture such that said reaction mixture has a second pH higher than said first pH; and adding, after said determining said pH increase, an acid to said reaction mixture to adjust said second pH to from said first pH plus about one pH unit to said first pH minus about one pH unit; crystallizing SAPO molecular sieve from the reaction mixture; and contacting an oxygenate with the crystallized SAPO molecular sieve catalyst to convert the oxygenate to olefin.