Patent ID: 8178737
Filing Date: 2012-05-15
Classification: C07C

Abstract:
1. A process for producing propylene comprising: (a) separating a feed stream comprising 1-butene, 2-butene, n-butane, and isobutane into a paraffins stream and a butenes stream; (b) reacting the butenes stream in the presence of an isomerization catalyst to produce an isomerized stream with increased concentration of 2-butene and having less than 5 wt. % butanes; (c) reacting the isomerized stream having less than 5 wt. % butanes and ethylene in the presence of a metathesis catalyst to produce a reaction mixture comprising propylene, (d) distilling the reaction mixture to separate an ethylene stream, a propylene stream, and a bottoms stream comprising 1-butene, 2-butenes, and C5 and higher olefins; (e) distilling the bottoms stream to produce a light stream comprising 1-butene and 2-butenes and a heavy stream comprising C5 and higher olefins; and (f) recycling at least a portion of the light stream to step (b), wherein the butenes stream comprises butanes in an amount of less than 5 wt. %.