PREPARATION OF PROPILANIUM BY MEANS OF SIMULTANEOUS DEHYDRATATION AND SKELETAL ISOMERIZATION OF ISOBUTANOL ON ACID CATALYSTS WITH A FOLLOWING METATHESIS

摘要

The present invention relates to a method for producing propylene, in which at the first stage isobutanol is subjected to simultaneous dehydration and skeletal isomerization to obtain mainly the corresponding olefins having the same number of carbon atoms and essentially including a mixture of n-butenes and isobutene, and the second stage, n-butenes are subjected to metathesis, the method includes the steps of: a) introducing into the reactor a stream (A) including isobutanol, optionally water, an optionally inert component, b) said stream bring into contact with the catalyst in the specified reactor under conditions effective for the dehydration and skeletal isomerization of at least part of isobutanol to obtain a mixture of n-butenes and isobutene, c) the stream (B) is captured from the said reactor, water, the inert component, are removed if it is present, and unreacted isobutanol, if present, to obtain a mixture of n-butenes and isobutene, d) fractionate the mixture to obtain a stream of n-butenes (N) and to remove the main part of isobutene, optionally recycled from outflow (A), to the dehydration / isomerization reactor from step b), e) the stream (N) is directed to the metathesis reactor and the stream (N) is contacted with the catalyst in the specified metathesis reactor, optionally in the presence of ethylene, under conditions effective to produce propylene, f) capture stream (P) from said metathesis reactor, comprising mainly propylene, unreacted n-butenes, heavy fractions, optionally unreacted ethylene, g) fractionate stream (P) to trap propylene, and optional recycle unreacted