Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – Organic polymerization
Reexamination Certificate
1998-11-30
2001-03-27
Beck, Shrive (Department: 1764)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
Organic polymerization
C422S131000, C422S132000, C422S186220, C585S518000, C585S520000, C585S643000
Reexamination Certificate
active
06207115
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a process for the conversion of an olefinic C
4
cut to polyisobutene and to propylene. Part or all of the C
4
cut may originate from the conversion of an olefinic C
5
cut. When the cuts originate from a steam cracking operation, a further aim of the present invention is to optimise the relative ethylene-propylene selectivity of the steam cracking procedure using this process.
Steam cracking of feeds constituted by light paraffin cuts supplies ethylene and propylene for the petrochemical industry. It also provides a number of other heavier products, in particular a C
4
hydrocarbon cut which contains mainly 1,3-butadiene, isobutene, n-butenes and butanes, accompanied by traces of acetylenic hydrocarbons, and a C
5
hydrocarbon cut which contains mainly C
5
diolefins, methylbutenes, n-pentenes and pentanes accompanied by traces of acetylenic hydrocarbons.
Like wise, catalytic cracking of heavy hydrocarbon feeds, in particular fluid catalytic cracking (FCC), produces lighter products, among them a C
4
hydrocarbon cut which contains mainly isobutane, isobutene, n-butenes and butanes, accompanied by small quantities of 1,3-butadiene and acetylenic hydrocarbons, and a C
5
hydrocarbon cut which contains mainly pentanes, methylbutenes and n-pentenes, accompanied by small quantities of C5 diolefins and acetylenic hydrocarbons.
Until recently, only the 1,3-butadiene and the isobutene were of use in the polymer industry, in particular in the tire industry for the former. An increase in tyre lifetime and a relative stagnation of demand has led to a surplus of butadiene which is not used to any great extent. In contrast isobutene has gained in importance as it can be used to synthesize polymers with many uses.
SUMMARY OF THE INVENTION
The present invention provides a process for the treatment of a C
4
hydrocarbon cut containing mainly isobutene, n-butenes, butanes and varying amounts of 1,3-butadiene, which includes the transformation of isobutene to polyisobutene, and which can transform 1,3-butadiene and n-butenes to propylene for polymerisation, for example. Part or all of the C
4
hydrocarbons may also originate from an olefinic C
5
cut which is mainly transformed, after hydroisomerisation, to propylene and a mixture of mainly 1-butene and isobutene by metathesis with ethylene.
The relative proportions of ethylene and propylene produced in a steam cracking operation can be modulated to a certain extent by changing the nature of the feed and modifying the cracking conditions (severity). However, an operating mode intended to produce a higher proportion of propylene inevitably produces larger quantities of C
4
cut, C
5
cut and heartier petrol fractions of poor quality.
A further aim of the present invention is to optimise the relative ethylene-propylene selectivity of the steam cracking procedure by treating the C
4
or C
5
steam cracking hydrocarbon cuts to produce, inter alia, propylene, thus enabling the relative proportions of ethylene and propylene to be adjusted without requiring a change in the cracking severity.
More precisely, the object of the invention is to provide a process for the conversion of an olefinic C
4
cut to polyisobutene and to propylene, the cut containing mainly diolefins, 1-butene, isobutene and acetylenic impurities, said process comprising the following steps which are carried out successively:
1) selective hydrogenation of the diolefins and acetylenic impurities with simultaneous isomerisation of the 1-butene to 2-butenes, by passing said cut in the liquid phase over a catalyst comprising at least one metal selected from the group formed by nickel, palladium and platinum, deposited on a support, at a temperature of 20-200° C., a pressure of 1-5 MPa, and a space velocity of 0.5-10 h
−1
, with a H
2
/diolefin (molar) ratio of 0.5 to 5, preferably 1 to 3, to obtain an effluent containing mainly 2-butene and isobutene, and containing practically no diolefins or acetylenic compounds;
2) polymerisation of the isobutene contained in the effluent from step 1 to polyisobutene, in the presence of an acid catalyst, at a temperature of −100° C. to +100° C., and at a pressure such that the reaction is carried out in the liquid phase, wherein the isobutene may be separated from the other constituents of the cut from step 1 before polymerisation, to obtain polyisobutene and a residual C
4
cut without a polymer;
3) metathesis of the residual C
4
cut with ethylene, in the presence of a catalyst comprising at least one rhenium oxide deposited on a support, at a temperature in the range 0° C. to 100° C., and at a pressure which is at least equal to the vapour pressure of the reaction mixture at the reaction temperature, to obtain an effluent containing propylene, metathesis being followed by separation of the propylene.
In the C
4
cut which is treated using the above process, the isobutene and the 1-butene may completely or partially originate from an olefinic C5 cut which can contain mainly diolefins, n-pentenes, methylbutenes and acetylenic impurities, which is subjected to a treatment comprising at least the two following steps which are carried out successively:
1) selective hydrogenation of the diolefins and acetylenic impurities with simultaneous isomerisation of the alpha olefins containing 5 carbon atoms to 2-pentenes and 2-methyl-2-butene, by passing said cut in the liquid phase over a catalyst comprising at least one metal selected from the group formed by nickel, palladium and platinum, and deposited on a support, at a temperature of 20-200° C., a pressure of 1-5 MPa, and a space velocity of 0.5-10 h
−1
, with a H
2
/diolefin (molar) ratio of 0.5 to 5, preferably 1 to 3, to obtain an effluent containing mainly 2-pentene and 2-methyl-2-butene, and containing practically no diolefins or acetylenic compounds;
2) metathesis of at least a portion of the effluent from the preceding step with ethylene, in the presence of a catalyst comprising at least one rhenium oxide deposited on a support, at a temperature in the range 0° C. to 100° C., and at a pressure which is at least equal to the vapour tension of the reaction mixture at the reaction temperature, to obtain an effluent containing mainly propylene, 1-butene and isobutene, metathesis being followed by separation of the propylene;
3) introduction of the 1-butene and isobutene mixture to the selective hydrogenation step for the C
4
cut.
REFERENCES:
patent: 3501551 (1970-03-01), Heidler et al.
patent: 3728414 (1973-04-01), Helden et al.
patent: 4132745 (1979-01-01), Amigues et al.
patent: 4287378 (1981-09-01), Pennella et al.
patent: 4324938 (1982-04-01), Cosyns et al.
patent: 4558170 (1985-12-01), Chen et al.
patent: 5026935 (1991-06-01), Leyshon et al.
patent: 5414179 (1995-05-01), Hunt et al.
patent: 5449852 (1995-09-01), Chauvin et al.
patent: 0 213 401 (1987-03-01), None
patent: 2 442 246 (1980-06-01), None
patent: 2 709 125 (1995-02-01), None
patent: 72013251 (1967-12-01), None
Abstract, DataBase WPI, Section Ch, Wk. 7217, (JP-B-47 013 251), Derwent Publications, Ltd., London, GB.
Chodorge Jean-Alain
Commereuc Dominique
Cosyns Jean
Duee Didier
Torck Bernard
Beck Shrive
Doroshenk Alexa A.
Institut Francais du Pe'trole
Millen White Zelano & Branigan
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