Patent ID: 6977321

Claim:
A process for the production of propylene from an olefinic feedstock containing at least one olefin of C 4 or greater comprising: (a) providing a crystalline silicate catalyst having an MFI structure and containing aluminum and silicon in the catalyst framework to provide a silicon/aluminum atomic ratio; (b) subjecting said catalyst to a pretreatment procedure involving heating the catalyst in steam and thereafter de-aluminating the catalyst by treating the catalyst with a complexing agent for aluminum to remove aluminum from the catalyst framework and providing a catalyst of increased silicon/aluminum atomic ratio within the range of 180 to 1000; and (c) contacting the pretreated catalyst with the olefinic feedstock containing at least one olefin of C 4 or greater to produce an effluent containing propylene in which the propylene yield on an olefin basis is from 30 to 50% based on the olefinic content of the feedstock.