h Nemati Arbatani - Department of Chemical Engineering, Tarbiat Modares University, Tehran, Iran.
j Towfighi Daryan - Department of Chemical Engineering, Tarbiat Modares University, Tehran, Iran.
f Kalantar Kohdami - Department of Chemical Engineering, Tarbiat Modares University, Tehran, Iran.

Effect of the crystallization duration as a synthesis parameter on the physicochemical and catalytic properties of microporous crystalline silicoaluminophosphates (SAPOs) used in the methanol to olefin (MTO) reaction, has been studied. It has been determined that increasing in duration of crystallization led to the formation of larger crystals, which caused a rapid deactivation of the samples in the reaction of methanol conversion to light olefins and increasing duration of crystallization led to improve relative crystallinity and light olefins selectivity, until to a appropriate time, after that it caused to decreased these parameters. As a result, the catalyst synthesized for 24 h, had maximum light olefins selectivity (81.5%).

MTO reaction, light olefins selectivity, relative crystallinity