Patent ID: 6777582
Filing Date: 2004-08-17
Classification: C07C

Abstract:
A process for the conversion of a n-butene feed containing both 1-butene and 2-butene to propylene comprising the steps of:(a) passing said n-butene feed and a 2-pentene feed into an autometathesis reactor in contact with a methathesis catalyst whereby said 1-butene and 2-butane react to form propylene and 2-pentene and said 2-pentene stream reacts with 1-butene to form additional propylene and 3-hexene; (b) separating the effluent from said autometathesis reactor into a propylene product stream, an unreacted n-butene stream, a 2-pentene stream and a product 3-hexene stream; and (c) recycling at least a portion of said separated 2-pentene stream as said 2-pentene feed to said autometathesis reactor; wherein said n-butene feed is obtained from a pyrolysis cracking process and wherein only a portion of said separated 2-pentene stream is recycled leaving an unrecycled portion comprising the further steps of hydrogenating said unrecycled portion of said 2-pentene stream and at least a portion of said product 3-hexene stream and then recycling these hydrogenated streams back to the pyrolysis cracking process.