Patent ID: 7973208

Claim:
A process for converting methanol to light olefins comprising contacting the methanol with a catalyst at conversion conditions, the catalyst comprising a crystalline metallo-aluminophosphate molecular sieve having a chemical composition on an anhydrous basis expressed by the empirical formula: (EL x Al y P z )O 2 where EL is silicon, “x” is the mole fraction of EL and has a value of at least 0.005, “y” is the mole fraction of Al and has a value of at least 0.01, “z” is the mole fraction of P and has a value of at least 0.01 and x+y+z=1, the molecular sieve characterized in that it has predominantly a roughly rectangular parallelepiped crystal morphology, wherein the average smallest crystal dimension is at least 50 nanometers and has an aspect ratio of less than or equal to 5 and wherein a first smaller portion of said crystalline metallo aluminophosphate molecular sieve has from about 5 to 20 wt % SiO 2 and wherein a second larger portion of said crystalline metallo aluminophosphate molecular sieve has from about 1 to 5 wt % SiO 2 .