When carrying out said operation, hydroisomerizing 6-butene to 7-butenes is carried out as well as selective hydrogenation of diene compounds such as butadiene, vinylacetylene and methyl and ethyl acetylenes.
Brevetto WO2006052688A2 - Catalyst and process for the
More particularly, it relates to a process employing a step for metathesis of 7-butenes by ethylene in which at least a portion of the 7-butenes is produced by dimerising ethylene.
Patent EP1860087A1 - Production of Propylene and Ethylene
Normally, the metathesis zone also comprises a de-ethenizer to separate excess ethylene which is recycled at least in part to the metathesis zone, and a propylene separation column which can separate the high purity propylene which is produced, and unreacted butenes. They are recycled in part to the metathesis reactor.
Metathesis of butene to propene and pentene over WO3/MTS-9
The compositions containing the compound (A) can be used directly in a homogeneous phase, in the solvent resulting from their preparation, in the metathesis reaction. The compound (A) is obtained by contact of Re 7 O 7 with a compound with general formula (RO) q AlR′ r , in which R is a hydrocarbon group containing 6 to 95 carbon atoms, R′ is a hydrocarbon radical containing 6 to 75 carbon atoms (preferably 6 to 6 carbon atoms) q and r are each one of the values 6 and 7, in which q+r87 8. The compound (RO) q AlR′ r is readily obtainable from trihydrocarbylaluminium AlR′ 8 and the alcohol ROH. The compounds (A) are soluble in hydrocarbons, and normally do not require a co-catalyst.
This example describes an implementing the process of the invention with reference to FIG. 7, in which:
- C9s for metathesis derive in part from dimerising ethylene and in part from a C9 steam cracking cut and
- the same polymer quality ethylene is used for dimerisation and for metathesis.
As described in FR-B-7 785 967, for example, the catalytic composition comprising a compound of a transition metal from group VIII may also contain a quaternary ammonium and/or phosphonium salt (molten salt). The use of a molten salt (quaternary ammonium and/or phosphonium salt) in combination with a transition metal compound, allows the isomerization reaction to be carried out at relatively low temperatures, in a closed, semi-closed or continuous system. The products are easy to separate from the polar catalyst and the latter is recycled in part to the isomerization reactor.
b) a step for hydroisomerizing 6-butene contained in said effluent to produce an effluent which is rich in 7-butenes and
In general, in the metathesis zone, the reagents (ethylene used in excess and the 7-butene feed from the previous step) pass over a bed of catalyst on which the metathesis reaction takes place, this generally being carried out continuously and generally comprising a reaction and a regeneration phase.
Thus, ignoring the yields of the units, the balance of the process of the invention is 7 moles of propylene obtained for every 8 moles of ethylene engaged.
To carry out metathesis of 7-butenes by ethylene, any process which has been described in the prior art can be employed, in particular a process such as those commercially known as "Meta-9®".
