Patent ID: 7868216

Claim:
A process for producing high purity propylene, comprising: a) dimerising ethylene into an effluent consisting essentially of 1-butene; passing said effluent and hydrogen directly into a hydroisomerization reactor, containing a hydroisomerizing catalyst, and b) catalytically hydroisomerizing 1-butene contained in said effluent to produce an effluent rich in 2-butenes and having no isobutene, and c) in a metathesis reactor containing a metathesis catalyst, said metathesis reactor being separate from said hydroisomerization reactor, conducting metathesis with ethylene of 2-butenes in said effluent rich in 2-butenes to produce high purity propylene, whereas said hydroisomerizing catalyst comprises a group VIII metal and the metathesis catalyst comprises at least one rhenium, molybdenum or tungsten compound, and wherein said metathesis is conducted at a lower temperature than said hydroisomerizing of 1-butene.