WO2013116922A1 - Procédé d'oligomérisation de l'éthylène dans un multiréacteur avec dispositif de recyclage - Google Patents

Procédé d'oligomérisation de l'éthylène dans un multiréacteur avec dispositif de recyclage Download PDF

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WO2013116922A1
WO2013116922A1 PCT/CA2013/000046 CA2013000046W WO2013116922A1 WO 2013116922 A1 WO2013116922 A1 WO 2013116922A1 CA 2013000046 W CA2013000046 W CA 2013000046W WO 2013116922 A1 WO2013116922 A1 WO 2013116922A1
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reactor
catalyst
ethylene
oligomerization
mixed
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PCT/CA2013/000046
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P. Scott Chisholm
Stephen John Brown
Eric Clavelle
Kamal Elias Serhal
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Nova Chemicals (International) S.A.
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Publication of WO2013116922A1 publication Critical patent/WO2013116922A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2/00—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms
    • C07C2/02—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons
    • C07C2/04—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons by oligomerisation of well-defined unsaturated hydrocarbons without ring formation
    • C07C2/06—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons by oligomerisation of well-defined unsaturated hydrocarbons without ring formation of alkenes, i.e. acyclic hydrocarbons having only one carbon-to-carbon double bond
    • C07C2/08—Catalytic processes
    • C07C2/26—Catalytic processes with hydrides or organic compounds
    • C07C2/36—Catalytic processes with hydrides or organic compounds as phosphines, arsines, stilbines or bismuthines
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2/00—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms
    • C07C2/02—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons
    • C07C2/04—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons by oligomerisation of well-defined unsaturated hydrocarbons without ring formation
    • C07C2/06—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons by oligomerisation of well-defined unsaturated hydrocarbons without ring formation of alkenes, i.e. acyclic hydrocarbons having only one carbon-to-carbon double bond
    • C07C2/08—Catalytic processes
    • C07C2/26—Catalytic processes with hydrides or organic compounds
    • C07C2/32—Catalytic processes with hydrides or organic compounds as complexes, e.g. acetyl-acetonates
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2531/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • C07C2531/16—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes
    • C07C2531/18—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes containing nitrogen, phosphorus, arsenic or antimony
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2531/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • C07C2531/26—Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups C07C2531/02 - C07C2531/24
    • C07C2531/34—Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups C07C2531/02 - C07C2531/24 of chromium, molybdenum or tungsten
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

  • This invention relates to the oligomerization of ethylene using a Cr catalyst having a so-called "bridged diphosphine ligand" in a process that uses at least two different types of reactors in series, namely at least one mixed reactor and at least one tubular reactor, with the provisio that part of the oligomer product that is discharged from the tubular reactor is recycled to the mixed reactor.
  • Alpha olefins are commercially produced by the oligomerization of ethylene in the presence of a simple alkyl aluminum catalyst (in the so called “chain growth” process) or alternatively, in the presence of an organometallic nickel catalyst (in the so called Shell Higher Olefins, or "SHOP" process). Both of these processes typically produce a crude oligomer product having a broad distribution of alpha olefins with an even number of carbon atoms (i.e. butene-1 , hexene-1 , octene-1 etc.). The various alpha olefins in the crude oligomer product are then typically separated in a series of distillation columns.
  • Butene-1 is generally the least valuable of these olefins as it is also produced in large quantities as a by-product in various cracking and refining processes. Hexene-1 and octene-1 often command comparatively high prices because these olefins are in high demand as comonomers for linear low density polyethylene (LLDPE).
  • LLDPE linear low density polyethylene
  • diphosphine ligand and are described in further detail by Carter et al. (Chem. Comm. 2002, p 858-9). As described in the Chem. Comm. paper, these catalysts preferably comprise a diphosphine ligand in which both phosphine atoms are bonded to two phenyl groups that are each substituted with an ortho-methoxy group. Hexene-1 is produced with high activity and high selectivity by these catalysts. Similar diphosphine/tetraphenyl ligands are disclosed by Blann et al. in
  • WO04/056478 and WO 04/056479 (now US 2006/0229480 and US 2006/0173226).
  • the disphosphine/tetraphenyl ligands disclosed by Blann et al. generally do not contain polar substituents in ortho positions.
  • the "tetraphenyl" diphosphine ligands claimed in the '480 application must not have ortho substituents (of any kind) on all four of the phenyl groups and the "tetraphenyl" diphosphine ligands claimed in '226 are characterized by having a polar substituent in a meta or para position.
  • the oligomerization of ethylene is highly exothermic.
  • the performance of the Cr bridged diphosphine catalysts is quite temperature dependent. Preferred operating temperatures are from 50 - 150°C, especially from 60 - 90 °C. Sudden temperature changes (especially temperature drops) have been observed to lead to the formation of by-product polymer - which is highly undesirable. In addition, the selectivity of the catalyst has been observed to change with temperature. Accordingly, good temperature control is highly desirable and an isothermal (as opposed to adiabatic) reaction is especially preferred.
  • a first preferred condition is to provide a well mixed reactor in order to minimize gradients in reactor temperature, ethylene concentration and catalyst concentration.
  • the first preferred condition i.e. a well mixed reactor, as noted above
  • the second preferred condition - namely high ethylene concentrations - by operating a well mixed reactor (such as CSTR) at a high ethylene concentration and with low ethylene conversion.
  • a well mixed reactor such as CSTR
  • the ethylene concentration in the discharge from a well mixed CSTR will correspond to the ethylene concentration in the bulk.
  • a problem with the use of a CSTR in this process is that the product discharge will contain large amounts of unreacted ethylene.
  • the present invention mitigates these problems.
  • the present invention provides:
  • a process for the oligomerization of ethylene in at least two reactors wherein said process comprises
  • said catalyst system comprises a chromium catalyst having a bridged diphosphine ligand.
  • the present invention must include a recycle flow from the discharge of the tubular reactor to the mixed reactor.
  • a semi-batch process is enabled (whereby ethylene is added to the reactor on a continuous/semi continuous basis, but the oligomer product is only withdrawn in a batch or semi batch manner).
  • reactor system may be fitted with two or more tubular reactors. This would facilitate operating the process at low rates (with one tubular reactor) and higher rates with the additional tubular reactor.
  • Figure 1 is a process flow diagram that illustrates a preferred embodiment of the invention.
  • Figure 1 illustrates a process flow diagram of a preferred embodiment of the present invention.
  • the mixed reactor 1 receives fresh ethylene via feed line 5 and catalyst feeds via feed line 6. It is especially preferred to also add hydrogen to mixed reactor 1. Thus, hydrogen may be added in the ethylene feed line 5 or an alternative feed line. Recycle from the tubular reactor 2 is also added to the mixed reactor, via line 4.
  • mixed reactor 1 has a liquid 7 level that defines a gas space 10 above the liquid reaction mixture.
  • mixed reactor 1 is a continuously stirred tank reactor (CSTR) and mixing is provided by an agitator.
  • CSTR continuously stirred tank reactor
  • mixed reactor 1 is equipped with a gas/liquid ejector 8.
  • the recycle liquid from reactor 2 is directed into reactor 1 in the form of a liquid jet through gas/liquid ejector 8 by way of recycle line 4.
  • the liquid jet flows through a zone of reduced cross sectional area, thereby forming a zone of especially fast liquid flow (which, in turn, produces low pressure).
  • the gas/liquid ejector 8 has an opening in the gas space 10 that communicates with the low pressure zone of the gas/liquid ejector 8 and this allows ethylene to be entrained in liquid and mixed in the jet flow.
  • the flow from the ejector - which consists of the reaction liquid and entrained/dissolved ethylene - is directed into the liquid of mixed reactor 1.
  • gas/liquid ejectors are known in the art and are also commonly referred to as Venturi mixers and/or jet ejectors (as well as gas/liquid ejectors). Reactors equipped with such an ejector are commonly referred to as "gas circulation” or “jet loop” reactors.
  • the ejector 8 is only shown in a symbolic or representative manner (as are pump 3 and reactors 1 and 2) with much detail omitted.
  • the liquid flow channel for the jet and the gas flow channel (or channels) which allow gas to be entrained in the liquid are omitted. This type of detail will be readily
  • the liquid flow through the jet is at least 10 meters per second, m/s (and especially at least 20m/s) in order to efficiently entrain the ethylene.
  • a pump 3 to provide the propulsion that is required to circulate the flow through the jet; the mixed reactor 1 and the tubular reactor 2.
  • reaction liquid circulates from the discharge of mixed reactor 1 , through pump 3 and reactor 2 and then back to reactor 1.
  • a combination of the gas/liquid ejector 8 and the pump 3 providing mixing in reactor 1 is a preferred embodiment of this invention.
  • the cooling system for the present invention is provided as an external cooling system (i.e.: it is preferred to avoid the use of internal cooling coils).
  • tubular reactor As previously noted, it is difficult to mix high levels of ethylene and/or catalyst in a tubular reactor. Accordingly, it is especially preferred to add catalyst and ethylene to only the mixed reactor (i.e. to avoid adding fresh ethylene and/or catalyst to the tubular reactor).
  • the term "tubular reactor” as used herein is meant to convey its conventional meaning, namely a reactor with a high length/diameter (or UD) ratio. A single tube or multiple tube bundle may be suitably employed. Tubular reactors typically do not have internal agitators and that is the case in the present invention, with pump 3 preferably providing the force to move the reaction liquid.
  • the ethylene is most preferably added as a gas although a portion of the ethylene may be added as a liquid (thereby cooling the reactor as the liquid ethylene flashes to a gas). It is especially preferred to add hydrogen with the ethylene. In one embodiment, a portion of the ethylene may be added below the liquid level (although this is not necessary). In another embodiment, the ethylene is added to the gas space 10 in reactor 1.
  • the process of the present invention has the additional advantage that it facilitates the start-up of the oligomerization.
  • the reactor system will be cleaned/purged according to good engineering practice.
  • Start-up liquid and (optionally) hydrogen may then be added to the reactor.
  • the amount of start-up liquid is preferably low (25-35% of the volume of the mixed reactor).
  • the start-up liquid may be any liquid that facilitates the reaction (such as an aliphatic, an aromatic, or even oligomer product from a previous reaction).
  • the pump preferably starts to circulate the liquid through the reactor system when adding the catalyst, thereby proving well mixed catalyst.
  • Ethylene is then gradually added to the mixed reactor to provide "light off' (or initiation of the reaction).
  • the start-up liquid is a very good solvent for the catalyst system (such as monochlorobenzene).
  • liquid level in the system increases as liquid oligomer is produced.
  • the liquid oligomer is then removed from the process. This may be done continuously (via a slip stream) or in a batch/semi-batch manner by way of product discharge line 9, through valve 1.
  • the process may be operated with additional solvent being added (for example, with the ethylene) or - alternatively - the proces may be operated without additional solvent being provided after start up.
  • the preferred catalyst system used in the process of the present invention must contain three essential components, namely:
  • Chromium Source (“Component (i)")
  • Any source of chromium that is soluble in the process solvent and which allows the oligomerization process of the present invention to proceed may be used.
  • Preferred chromium sources include chromium trichloride; chromium (III) 2- ethylhexanoate; chromium (III) acetylacetonate and chromium carbonyl complexes such as chromium hexacarbonyl. It is preferred to use very high purity chromium compounds as these should generally be expected to minimize undesirable side reactions. For example, chromium acetylacetonate having a purity of higher than 99% is commercially available (or may be readily produced from 97% purity material - using recrystallization techniques that are well known to those skilled in the art).
  • the ligand used in the oligomerization process of this invention is defined by the formula (R )(R 2 )-P 1 -bridge-P 2 (R 3 )(R 4 ) wherein R 1 , R 2 ,R 3 and R 4 are independently selected from the group consisting of hydrocarbyl and heterohydrocarbyl and the bridge is a moiety that is bonded to both phosphorus atoms.
  • Another family of suitable ligands uses a fluorocarbyl oxide (especially the aromatic group - C 6 F 5 ) for the R 4 group - with R 1 to R 3 being as defined above.
  • hydrocarbyl as used herein is intended to convey its conventional meaning - i.e. a moiety that contains only carbon and hydrogen atoms.
  • hydrocarbyl moiety may be a straight chain; it may be branched (and it will be recognized by those skilled in the art that branched groups are sometimes referred to as "substituted"); it may be saturated or contain unsaturation and it may be cyclic.
  • Preferred hydrocarbyl groups contain from 1 to 20 carbon atoms.
  • Aromatic groups - especially phenyl groups - are especially preferred.
  • the phenyl may be unsubstituted (i.e. a simple CeHs moiety) or contain substituents, particularly at an ortho (or "o") position.
  • heterohydrocarbyl as used herein is intended to convey its conventional meaning - more particularly, a moiety that contains carbon, hydrogen and heteroatoms (such as O, N, R and S).
  • the heterohydrocarbyl groups may be straight chain, branched or cyclic structures. They may be saturated or contain unsaturation.
  • Preferred heterohydrocarbyl groups contain a total of from 2 to 20 carbon +
  • each of R 1 , R 2 , R 3 and R 4 is a phenyl group (with an optional substituent in an ortho position on one or more of the phenyl groups).
  • Highly preferred ligands are those in which R to R 4 are independently selected from the group consisting of phenyl, o-methylphenyl (i.e. ortho-methylphenyl), o-ethylphenyl, o-isopropylphenyl and o-fluorophenyl. It is especially preferred that none of R 1 to R 4 contains a polar substituent in an ortho position.
  • the resulting ligands are useful for the selective tetramerization of ethylene to octene-1 with some co product hexene also being produced.
  • bridge refers to a moiety that is bonded to both of the phosphorus atoms in the ligand - in other words, the "bridge” forms a link between P 1 and P 2 .
  • Suitable groups for the bridge include hydrocarbyl and an inorganic moiety selected from the group consisting of N(CH 3 )-N(CH 3 )-, -B(R 6 )-, -Si(R 6 ) 2 -, -P(R 6 )- or -N(R 6 )- where R 6 is selected from the group consisting of hydrogen, hydrocarbyl and halogen.
  • the bridge is -N(R 5 )- wherein R 5 is selected from the group consisting of hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, aryloxy, substituted aryloxy, halogen, alkoxycarbonyl, carbonyloxy, alkoxy, aminocarbonyl, carbonylamino, dialkylamino, silyl groups or derivatives thereof and an aryl group substituted with any of these substituents.
  • a highly preferred bridge is amino isopropyl (i.e. when R 5 is isopropyl).
  • two different types of ligands are used to alter the relative amounts of hexene and octene being produced.
  • the use of a ligand that produces predominantly hexene may be used in combination with a ligand that produces predominantly octene.
  • the activator may be any compound that generates an active catalyst for ethylene oligomerization with components (i) and (ii). Mixtures of activators may also be used. Suitable compounds include organoaluminum compounds, organoboron compounds and inorganic acids and salts, such as tetrafluoroboric acid etherate, silver tetrafluoroborate, sodium hexafluoroantimonate and the like. Suitable organoaluminium compounds include compounds of the formula AIR3, where each R is independently -C12 alkyl, oxygen or halide, and compounds such as LiAIH 4 and the like. Examples include trimethylaluminium (TMA), triethylaluminium (TEA), tri- isobutylaluminium (TIBA), tri-n-octylaluminium, methylaluminium dichloride,
  • Alumoxanes are well known in the art as typically oligomeric compounds which can be prepared by the controlled addition of water to an alkylaluminium compound, for example trimethylaluminium. Such compounds can be linear, cyclic, cages or mixtures thereof. Commercially available alumoxanes are generally believed to be mixtures of linear and cyclic compounds.
  • the cyclic alumoxanes can be represented by the formula [R 6 AIO]s and the linear alumoxanes by the formula R 7 (R 8 AIO)s wherein s is a number from about 2 to 50, and wherein R 6 , R 7 , and R 8 represent hydrocarbyl groups, preferably Ci to Ce alkyl groups, for example methyl, ethyl or butyl groups.
  • Alkylalumoxanes especially methylalumoxane (MAO) are preferred.
  • alkylalumoxanes may contain a proportion of trialkylaluminium.
  • commercial MAO usually contains approximately 10 wt % trimethylaluminium (TMA), and commercial "modified MAO" (or “MMAO") contains both TMA and TIBA.
  • TMA trimethylaluminium
  • MMAO modified MAO
  • Quantities of alkylalumoxane are generally quoted herein on a molar basis of aluminium (and include such "free" trialkylaluminium).
  • organoboron compounds examples include boroxines, NaBH 4 , trimethylboron, triethylboron, dimethylphenylammoniumtetra(phenyl)borate,
  • Activator compound (iii) may also be or contain a compound that acts as a reducing or oxidizing agent, such as sodium or zinc metal and the like, or oxygen and the like.
  • the quantity of activating compound to be employed is easily determined by simple testing, for example, by the preparation of small test samples which can be used to oligimerize small quantities of ethylene and thus to determine the activity of the produced catalyst. It is generally found that the quantity employed is sufficient to provide 0.5 to 1000 moles of aluminium (or boron) per mole of chromium.
  • MAO is the presently preferred activator. Molar Al/Cr ratios of from 1/1 to 1500/1 , especially 300/1 to 900/1 are preferred.
  • the chromium (component (i)) and ligand (component (ii)) may be present in any molar ratio which produces oligomer, preferably between 100: 1 and 1 : 100, and most preferably from 10:1 to 1 :10, particularly 3:1 to 1 :3. Generally the amounts of (i) and (ii) are approximately equal, i.e. a ratio of between 2:1 and 1 :2.
  • Components (i)-(iii) of the catalyst system utilized in the present invention may be added together simultaneously or sequentially, in any order, and in the presence or absence of ethylene in any suitable solvent, so as to give an active catalyst.
  • components (i), (ii) and (iii) and ethylene may be contacted together simultaneously, or components (i), (ii) and (iii) may be added together simultaneously or sequentially in any order and then contacted with ethylene, or components (i) and (ii) may be added together to form an isolable metal-ligand complex and then added to component (iii) and contacted with ethylene, or components (i), (ii) and (iii) may be added together to form an isolable metal-ligand complex and then contacted with ethylene.
  • Suitable solvents for contacting the components of the catalyst or catalyst system include, but are not limited to, hydrocarbon solvents such as heptane, toluene, -hexene and the like, and polar solvents such as diethyl ether, tetrahydrofuran, acetonitrile, dichloromethane, chloroform, chlorobenzene, acetone and the like.
  • a preferred solvent is the oligomer product that is produced by the present process or some fraction thereof - such as hexene, octene or a mixture of the two.
  • the catalyst components may be mixed together in the oligomerization reactor, or - alternatively - some or all of the catalyst components may be mixed together outside of the oligomerization reactor.
  • This method of catalyst synthesis is illustrated in the examples.
  • the solvent that is used to prepare the catalyst is preferably the olefinic product that is produced by the reactor (or some portion thereof). We have found that the use of octene generally works well. However, some catalyst components have comparatively low solubility in octene.
  • MAO that is made solely with trimethylaluminum (as opposed to "modified MAO" which also contains some higher alkyl aluminum, such as triisobutyl aluminum) is less soluble in octene than in some cyclic hydrocarbons such as xylene or tetralin. Accordingly, when one or more catalyst components are mixed together outside of the oligomerization reactor, the use of toluene, xylene chlorobenzene, or tetralin as the solvent may be preferred.
  • the xylene may be a mixture of ortho, meta and para isomers - i.e. it is not necessary to use a pure isomer.
  • a variety of methods are known to purify solvents used in the oligomerization process including use of molecular sieves (3A), adsorbent alumina and supported de-oxo copper catalyst.
  • 3A molecular sieves
  • adsorbent alumina adsorbent alumina
  • supported de-oxo copper catalyst a variety of methods are known to purify solvents used in the oligomerization process.
  • the process solvent is first contacted with molecular sieves, followed by adsorbent alumina, then followed by supported de-oxo copper catalyst and finally followed by molecular sieves.
  • the process solvent is first contacted with molecular sieves, followed by adsorbent alumina and finally followed by molecular sieves.
  • the process solvent is contacted with adsorbent alumina.
  • the preferred purifier system consists of molecular sieves, followed by adsorbent alumina and finally followed by another set of molecular sieves.
  • the catalyst components (i), (ii) and (iii) utilized in the present invention can be unsupported or supported on a support material, for example, silica, alumina, MgC or zirconia, or on a polymer, for example polyethylene, polypropylene, polystyrene, or poly(aminostyrene). If desired the catalysts can be formed in situ in the presence of the support material, or the support material can be pre-impregnated or premixed, simultaneously or sequentially, with one or more of the catalyst components.
  • the quantity of support material employed can vary widely, for example from 100,000 to 1 gram per gram of metal present in the transition metal compound. In some cases, the support material can also act as or as a component of the activator compound (iii). Examples include supports containing alumoxane moieties.
  • Oligomerization reactions can generally be conducted under solution phase, slurry phase, gas phase or bulk phase conditions.
  • Suitable temperatures range from 10° C to +300° C preferably from 10° C to 150° C, especially from 20 to 80° C.
  • Suitable pressures are from atmospheric to 800 atmospheres (gauge) preferably from 5 atmospheres to 150 atmospheres, especially from 10 to 100 atmospheres.
  • the oligomerization is typically carried out under conditions that substantially exclude oxygen, water, and other materials that act as catalyst poisons.
  • the reactor is preferably purged with a nonreactive gas (such as nitrogen or argon) prior to the introduction of catalyst.
  • a purge with a solution of MAO and/or aluminum alkyl may also be employed to lower the initial level of catalyst poisons.
  • oligomerizations can be carried out in the presence of additives to control selectivity, enhance activity and reduce the amount of polymer formed in oligomerization processes.
  • additives include, but are not limited to, hydrogen or a halide source (especially the halide sources disclosed in U.S.
  • the preferred catalysts of this invention predominantly produce hexene and octene (as shown in the examples) but smaller quantities of butene and Ci 0 + olefins are also produced.
  • the crude product stream may be separated into various fractions using, for example, a conventional distillation system. Mixtures of inert diluents or solvents also could be employed.
  • the preferred diluents or solvents are aliphatic and aromatic hydrocarbons and halogenated hydrocarbons such as, for example, isobutane, pentane, toluene, xylene, ethylbenzene, cumene, mesitylene, heptane, cyclohexane, methylcyclohexane, 1 -hexene, 1 -octene, chlorobenzene, dichlorobenzene, and the like, and mixtures such as IsoparTM.
  • isobutane pentane, toluene, xylene, ethylbenzene, cumene, mesitylene, heptane, cyclohexane, methylcyclohexane, 1 -hexene, 1 -octene, chlorobenzene, dichlorobenzene, and the like, and mixtures such as IsoparTM.
  • Techniques for varying the distribution of products from the oligomerization reactions include controlling process conditions (e.g. concentration of components (i)- (iii), reaction temperature, pressure, residence time) and properly selecting the design of the process and are well known to those skilled in the art.
  • a catalyst that produces ethylene homopolymer is deliberately added to the reactor in an amount sufficient to convert from 1 to 5 weight% of the ethylene feed to an ethylene homopolymer.
  • This catalyst is preferably supported. The purpose is to facilitate the removal of by-product polyethylene.
  • the ethylene feedstock for the oligomerization may be substantially pure or may contain other olefinic impurities and/or ethane.
  • One embodiment of the process of the invention comprises the oligomerization of ethylene-containing waste streams from other chemical processes or a crude ethylene/ethane mixture from a cracker as more fully described in co-pending Canadian patent application 2,708,01 1 (Krzywicki et al.).
  • the feedstock is preferably treated to remove catalyst poisons (such as oxygen, water and polar species) using techniques that are well known to those skilled in the art.
  • catalyst poisons such as oxygen, water and polar species
  • the technology used to treat feedstocks for polymerizations is suitable for use in the present invention and includes the molecular sieves, alumina and de-oxo catalysts described above for analogous treatment of the process solvent.
  • control systems required for the operation of mixed reactors and tubular reactors are well known to those skilled in the art and do not represent a novel feature of the present invention.
  • temperature, pressure and flow rate readings will provide the basis for most conventional control operations.
  • the increase in process temperature (together with reactor flow rates and the known enthalpy of reaction) may be used to monitor ethylene conversion rates.
  • the amount of catalyst may be increased to increase the ethylene conversion (or decreased to decrease ethylene conversion) within desired ranges.
  • basic process control may be derived from simple measurements of temperature, pressure and flow rates using conventional thermocouples, pressure meters and flow meters.
  • Advanced process control (for example, for the purpose of monitoring product selectivity or for the purpose of monitoring process fouling factors) may be undertaken by monitoring additional process parameters with more advanced instrumentation.
  • Known/existing instrumentation include in-line/on-line instruments such as NIR infrared, Fourier Transform Infrared (FTIR), Raman, mid-infrared, ultra violet (UV) spectrometry, gas chromatography (GC) analyzer, refractive index, on-line densitometer or viscometer.
  • FTIR Fourier Transform Infrared
  • GC gas chromatography
  • refractive index on-line densitometer or viscometer.
  • the measurement may be used to monitor and control the reaction to achieve the targeted stream properties including but not limited to concentration, viscosity, temperature, pressure, flows, flow ratios, density, chemical composition, phase and phase transition, degree of reaction, polymer content, selectivity.
  • the control method may include the use of the measurement to calculate a new control set point.
  • the control of the process will include the use of any process control algorithms, which include, but are not limited to the use of PID, neural networks, feedback loop control, forward loop control and adaptive control.
  • the oligomerization catalyst is preferably deactivated immediately downstream of the reactor as the product exits the reaction system. This is to prevent polymer formation and potential build up downstream of the reactor and to prevent isomerisation of the 1 -olefin product to the undesired internal olefins. It is generally preferred to flash and recover unreacted ethylene before deactivation. However, the option of deactivating the reactor contents prior to flashing and recovering ethylene is also acceptable. The flashing of ethylene is endothermic and may be used as a cooling source.
  • polar compounds such as water, alcohols and carboxylic acids
  • alcohols and/or carboxylic acids are preferred - and combinations of both are contemplated. It is generally found that the quantity employed to deactivate the catalyst is sufficient to provide deactivator to metal (from catalyst + activator) mole ratio between about 0.1 to about 4, especially from 1 to 2 (thus, when MAO is the activator, the deactivator is provided on a ratio based on moles of Cr + to moles of Al).
  • the deactivator may be added to the oligomerization product stream before or after the volatile unreacted reagents/diluents and product components are separated. In the event of a runaway reaction (e.g. rapid temperature rise) the deactivator can be immediately fed to the oligomerization reactor to terminate the reaction.
  • a runaway reaction e.g. rapid temperature rise
  • deactivation system may also include a basic compound (such as sodium hydroxide) to minimize isomerization of the products (as activator conditions may facilitate the isomerization of desirable alpha olefins to undesired internal olefins).
  • a basic compound such as sodium hydroxide
  • Polymer removal (and, optionally, catalyst removal) preferably follows catalyst deactivation.
  • Two “types” of polymer may exist, namely polymer that is dissolved in the process solvent and non-dissolved polymer that is present as a solid or "slurry".
  • Solid/non-dissolved polymer may be separated using one or more of the following types of equipment: centrifuge; cyclone (or hydrocyclone), a decanter equipped with a skimmer or a filter.
  • Preferred equipment include so called “self cleaning filters” sold under the name V-auto strainers, self cleaning screens such as those sold by Johnson Screens Inc. of New Brighton, Minnesota and centrifuges such as those sold by Alfa Laval Inc. of Richmond, VA (including those sold under the trade name Sharpies).
  • Soluble polymer may be separated from the final product by two distinct operations. Firstly, low molecular weight polymer that remains soluble in the heaviest product fraction (C20+) may be left in that fraction. This fraction will be recovered as "bottoms” from the distillation operations (described below). This solution may be used as a fuel for a power generation system.
  • An alternative polymer separation comprises polymer precipitation caused by the removal of the solvent from the solution, followed by recovery of the precipitated polymer using a conventional extruder.
  • the technology required for such separation/recovery is well known to those skilled in the art of solution polymerization and is widely disclosed in the literature.
  • the residual catalyst is treated with an additive that causes some or all of the catalyst to precipitate.
  • the precipitated catalyst is preferably removed from the product at the same time as by-product polymer is removed (and using the same equipment). Many of the catalyst deactivators listed above will also cause catalyst precipitation.
  • a solid sorbent such as clay, silica or alumina is added to the deactivation operation to facilitate removal of the deactivated catalyst by filtration or centrifugation.
  • Reactor fouling (caused by deposition of polymer and/or catalyst residue) can, if severe enough, cause the process to be shut down for cleaning.
  • the deposits may be removed by known means, especially the use of high pressure water jets or the use of a hot solvent flush.
  • the use of an aromatic solvent (such as toluene or xylene) for solvent flushing is generally preferred because they are good solvents for polyethylene.
  • the use of the heat exchanger that provides heat to the present process may also be used during cleaning operations to heat the cleaning solvent.
  • the oligomerization product produced from this invention is added to a product stream from another alpha olefins manufacturing process for separation into different alpha olefins.
  • "conventional alpha olefin plants” (wherein the term includes i) those processes which produce alpha olefins by a chain growth process using an aluminum alkyl catalyst, ii) the aforementioned "SHOP" process and iii) the production of olefins from synthesis gas using the so called Lurgi process) have a series of distillation columns to separate the "crude alpha product" (i.e.
  • the mixed hexene-octene product which is preferably produced in accordance with the present invention is highly suitable for addition/mixing with a crude alpha olefin product from an existing alpha olefin plant (or a "cut" or fraction of the product from such a plant) because the mixed hexene- octene product produced in accordance with the present invention can have very low levels of internal olefins.
  • the hexene-octene product of the present invention can be readily separated in the existing distillation columns of alpha olefin plants (without causing the large burden on the operation of these distillation columns which would otherwise exist if the present hexene-octene product stream contained large quantities of internal olefins).
  • the term "liquid product” is meant to refer to the oligomers produced by the process of the present invention which have from 4 to (about) 20 carbon atoms.
  • the distillation operation for the oligomerization product is integrated with the distillation system of a solution polymerization plant (as disclosed in Canadian patent application no. 2,708,011 , Krzywicki et al.).
  • toluene is present in the process fluid (for example, as a solvent for a MAO activator), it is preferable to add water to the "liquid product" prior to distillation to form a water/toluene azeotrope with a boiling point between that of hexene and octene.
  • the liquid product from the oligomerization process of the present invention preferably consists of from 20 to 80 weight% octenes (especially from 35 to 75 weight%) octenes and from 5 to 50 weight% (especially from 20 to 40 weight%) hexenes (where all of the weight% are calculated on the basis of the liquid product by 00%.
  • the preferred oligomerization process of this invention is also characterized by producing very low levels of internal olefins (i.e. low levels of hexene-2, hexene-3, octene-2, octene-3 etc.), with preferred levels of less than 10 weight% (especially less than 5 weight%) of the hexenes and octenes being internal olefins.
  • One embodiment of the present invention encompasses the use of components (i) (ii) and (iii) in conjunction with one or more types of olefin polymerization catalyst system (iv) to oligomerize ethylene and subsequently incorporate a portion of the trimerisation product(s) into a higher polymer.
  • Component (iv) may be one or more suitable polymerization catalyst system(s), examples of which include, but are not limited to, conventional Ziegler-Natta catalysts, metallocene catalysts, monocyclopentadienyl or "constrained geometry” catalysts, phosphinimine catalysts, heat activated supported chromium oxide catalysts (e.g.
  • a multi reactor process for the selective oligomerization of ethylene uses a chromium catalyst being a phosphorous - nitrogen - phosphorous ("P-N-P") ligand to produce a product stream that predominantly contains hexene-1 and octene-1.
  • the hexene-1 and octene-1 are useful as comonomers in the production of ethylene-alpha olefin copolymers.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Abstract

La présente invention concerne un système multiréacteur utilisé pour l'oligomérisation de l'éthylène en présence d'un catalyseur à base de chrome/pyridoxine phosphate (P-N-P). Le système de réacteur comprend un réacteur mixte et un réacteur tubulaire. Une partie du liquide de réaction est recyclée et réintroduite dans le réacteur mixte. Le réacteur mixte contient, de préférence, un jet gazeux/liquide pour faciliter le mélange de l'éthylène dans le liquide de réaction.
PCT/CA2013/000046 2012-02-08 2013-01-21 Procédé d'oligomérisation de l'éthylène dans un multiréacteur avec dispositif de recyclage WO2013116922A1 (fr)

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US20170158581A1 (en) * 2015-12-03 2017-06-08 Axens Use of an advanced multivariable controller to control alphabutol units
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WO2019011609A1 (fr) 2017-07-10 2019-01-17 IFP Energies Nouvelles Procede d'oligomerisation mettant en œuvre un vortex
WO2019011806A1 (fr) 2017-07-10 2019-01-17 IFP Energies Nouvelles Procede d'oligomerisation mettant en œuvre un dispositf reactionnel comprenant un moyen de dispersion
KR20190110959A (ko) * 2018-03-21 2019-10-01 주식회사 엘지화학 벤투리 관이 결합된 이젝터를 이용한 에틸렌의 올리고머화 방법
WO2021137713A1 (fr) * 2019-12-30 2021-07-08 Public Joint Stock Company "Sibur Holding" (Pjsc "Sibur Holding") Procédé de trimérisation d'éthylène et appareil de trimérisation d'éthylène
US11267909B2 (en) 2020-07-15 2022-03-08 Chevron Phillips Chemical Company Lp Oligomerization catalyst system activation and related ethylene oligomerization processes and reaction systems
WO2022132745A1 (fr) * 2020-12-15 2022-06-23 Shell Oil Company Procédé de production d'alpha-oléfines

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CA2723515A1 (fr) * 2010-12-01 2012-06-01 Nova Chemicals Corporation Gestion thermique lors de l'oligomerisation d'ethylene
CA2737713A1 (fr) * 2011-04-20 2012-10-20 Nova Chemicals Corporation Activation pour l'oligomerisation
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CN106061607A (zh) * 2013-12-23 2016-10-26 诺瓦化学品(国际)股份有限公司 具有原位催化剂制备的连续乙烯低聚化
US20160303551A1 (en) * 2013-12-23 2016-10-20 Nova Chemicals (International) S.A. Continuous ethylene oligomerization with in-situ catalyst preparation
US10343152B2 (en) * 2013-12-23 2019-07-09 Nova Chemicals (International) S.A. Continuous ethylene oligomerization with in-situ catalyst preparation
US10044164B2 (en) 2014-06-20 2018-08-07 Kla-Tencor Corporation Laser repetition rate multiplier and flat-top beam profile generators using mirrors and/or prisms
US10377681B2 (en) * 2015-12-03 2019-08-13 Axens Use of an advanced multivariable controller to control alphabutol units
JP2017105771A (ja) * 2015-12-03 2017-06-15 アクセンス アルファブトール装置を制御するための高度多変数コントローラの使用
US20170158581A1 (en) * 2015-12-03 2017-06-08 Axens Use of an advanced multivariable controller to control alphabutol units
WO2019011609A1 (fr) 2017-07-10 2019-01-17 IFP Energies Nouvelles Procede d'oligomerisation mettant en œuvre un vortex
WO2019011806A1 (fr) 2017-07-10 2019-01-17 IFP Energies Nouvelles Procede d'oligomerisation mettant en œuvre un dispositf reactionnel comprenant un moyen de dispersion
US11207657B2 (en) 2017-07-10 2021-12-28 IFP Energies Nouvelles Oligomerization method using a reaction device comprising a dispersion means
KR20190110959A (ko) * 2018-03-21 2019-10-01 주식회사 엘지화학 벤투리 관이 결합된 이젝터를 이용한 에틸렌의 올리고머화 방법
KR102638256B1 (ko) 2018-03-21 2024-02-20 주식회사 엘지화학 벤투리 관이 결합된 이젝터를 이용한 에틸렌의 올리고머화 방법
WO2021137713A1 (fr) * 2019-12-30 2021-07-08 Public Joint Stock Company "Sibur Holding" (Pjsc "Sibur Holding") Procédé de trimérisation d'éthylène et appareil de trimérisation d'éthylène
US11267909B2 (en) 2020-07-15 2022-03-08 Chevron Phillips Chemical Company Lp Oligomerization catalyst system activation and related ethylene oligomerization processes and reaction systems
US11859025B2 (en) 2020-07-15 2024-01-02 Chevron Phillips Chemical Company Lp Oligomerization catalyst system activation and related ethylene oligomerization processes and reaction systems
WO2022132745A1 (fr) * 2020-12-15 2022-06-23 Shell Oil Company Procédé de production d'alpha-oléfines

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