The present invention relates to a process for the production of propylene in which in a first step
isobutanol is subjected to a simultaneous
dehydration and skeletal isomerisation to make substantially corresponding olefins, having the same number of carbons and consisting essentially of a mixture of n-butenes and iso-
butene and in a second step n-butenes are subjected to methathesis, said process comprising:a) introducing in a reactor a
stream (A) comprising
isobutanol, optionally water, optionally an
inert component,b) contacting said
stream with a catalyst in said reactor at conditions effective to dehydrate and skeletal
isomerase at least a portion of the
isobutanol to make a mixture of n-butenes and iso-
butene,c) recovering from said reactor a
stream (B), removing water, the
inert component if any and unconverted isobutanol if any to get a mixture of n-butenes and iso-
butene,d) fractionating said mixture to produce a n-butenes stream (N) and to remove the essential part of isobutene optionally recycled with stream (A) to the
dehydration /
isomerization reactor of step b),e) sending the stream (N) to a methathesis reactor and contacting stream (N) with a catalyst in said methathesis reactor, optionally in the presence of
ethylene, at conditions effective to produce propylene,f) recovering from said methathesis reactor a stream (P) comprising essentially propylene, unreacted n-butenes, heavies, optionally unreacted
ethylene,g) fractionating stream (P) to recover propylene and optionally recycling unreacted n-butenes and unreacted
ethylene to the methathesis reactor.