Patent ID: 7074976
Filing Date: 2006-07-11
Classification: C07C,C10G

Abstract:
1. A method for forming propylene comprising providing a feedstock containing at least in part a first mixture of hydrocarbons comprising alpha olefins, internal linear olefins, and isoolefins having four carbon atoms per molecule, introducing said feedstock into a combination hydrogenation/double bond isomerization zone wherein (1) any diolefins and acetylenes that may be in said feedstock are converted at least in part to alpha and internal linear olefins, and (2) at least part of said alpha olefins in said feedstock and at least part of said alpha olefins formed by said hydrogenation are converted to additional internal linear olefins thereby producing as a product of said combination zone a second mixture that is enriched in internal linear olefins, passing said second mixture directly into a metathesis zone which favors the disproportionation of internal olefins with ethylene to produce propylene as a product of the process, recovering from said metathesis zone a third mixture separate from said propylene product that contains at least in part alpha olefins, internal olefins, and isoolefins, passing said third mixture into a skeletal isomerization zone wherein said isoolefins are converted at least in part to additional internal linear olefins to form a fourth mixture that is enriched in internal linear olefins, returning said fourth mixture as co-feed to at least one of said combination zone and said metathesis zone for the production of at least one of additional internal linear olefins in said combination zone and additional propylene in said metathesis zone.