KR20190110959A - Method For Oligomerizing Ethylene Using Ejecter With Combined Venturi Tube - Google Patents

Abstract

The present invention provides a method for oligomerizing ethylene comprising: a first step of preparing a catalyst composition by mixing a catalyst mixture comprising a catalyst and a promoter for 1 to 10 minutes; a second step of injecting the catalyst composition and ethylene into a reactor through an ejector in which a venture tube is coupled; a third step of carrying out an ethylene oligomerization reaction in the reactor; a fourth step of sending out 50 to 90 wt% of a solution under reaction in the reactor from the reactor; a fifth step of removing heat by passing the solution under reaction from the reactor through a heat exchanger; and a sixth step of mixing the preheated solution under reaction with the solution under reaction in the reactor. According to the invention, the activity of the reaction can be improved.

Description

Method for Oligomerizing Ethylene Using Ejecter With Combined Venturi Tube}

The present invention relates to a method for oligomerization of ethylene using an ejector in which a venturi tube is bonded, and to mix a catalyst and a promoter used for oligomerizing ethylene in advance for a predetermined time to obtain a uniform catalyst composition, and A method and apparatus for oligomerization of ethylene in which ethylene is fed through an ejector in which a venturi tube is coupled to the oligomerization reactor.

Linear alpha-olefins are widely used commercially as important materials for comonomers, detergents, lubricants, plasticizers, etc. In particular, 1-hexene and 1-octene are used in the production of linear low density polyethylene (LLDPE). It is often used as a comonomer to control the density.

Conventional manufacturing process of LLDPE (Linear Low-Density Polyethylene) is used to form a branch in the polymer backbone together with ethylene to control density by adjusting the density of density. Copolymerization was performed with comonomers such as 1-hexene and 1-octene.

Therefore, there is a problem that the price of the comonomer takes a large part of the manufacturing cost for the production of LLDPE having a high comonomer content. Various attempts have been made to solve this problem.

In addition, since alpha-olefins have different application fields or market sizes, the technology for selectively producing specific olefins is commercially important, and recently, 1-hexene or 1 through selective ethylene oligomerization There is a lot of research on chromium catalyst technology to produce octene with high selectivity.

Typically, the reaction raw materials fed to a continuous stirred-tank reactor (CSTR) for the synthesis of linear alpha-olefins are catalyst compositions and olefin monomers comprising ligand compounds, transition metal compounds such as chromium and promoters. In general, it is common to use a stirrer to increase the mass transfer efficiency in the reactor.

However, if the olefin monomer is not uniformly dispersed during the reaction, there is a problem that not only trimerization and tetramerization but also the polymer continues to grow and an undesirable long polymer is formed. In addition, the resulting polymer is often stuck to the stirrer and the mixing efficiency is often lowered, and thus there is a problem that the maintenance of the oligomerization device is expensive.

Accordingly, the present inventors perform a step of pre-mixing a catalyst raw material such as a ligand compound and a chromium source and a co-catalyst before inputting the reactor for a certain time, thereby improving the activity of the prepared catalyst composition and controlling the selectivity of the reaction to a predetermined level or more. It has been found that the production of non-oligomeric polymers from ethylene is minimized. In addition, when the catalyst composition and ethylene are supplied through an ejector in which a Venturi tube is coupled to the oligomerization reactor, the mixing efficiency of the catalyst composition and ethylene is very high, and thus, the reaction activity is also improved without requiring a separate stirrer. And the present invention was completed.

It is an object of the present invention to provide a method for oligomerization of ethylene which improves the mixing efficiency of the catalyst composition and ethylene used for oligomerization of ethylene and thereby improves the reaction activity.

One embodiment of the present invention comprises a first step of preparing a catalyst composition by mixing a catalyst mixture comprising a catalyst and a promoter for 1 to 10 minutes; A second step of injecting the catalyst composition and ethylene into the reactor through an ejector in which a venturi tube is coupled; A third step of carrying out an ethylene oligomerization reaction in the reactor; A fourth step of discharging 50 to 90% by weight of the reaction solution in the reactor from the reactor during the oligomerization reaction; A fifth step of removing heat by passing the reaction solution from the reactor through a heat exchanger; It provides a method for oligomerization of ethylene comprising a; and the sixth step of mixing the defrosted reaction solution in the reaction solution in the reactor.

According to the oligomerization method of ethylene of the present invention, a catalyst mixture is prepared by mixing a catalyst mixture comprising a catalyst and a promoter, and the catalyst composition and ethylene are fed into a reactor through an ejector in which a venturi tube is coupled, thereby providing a catalyst. Since the mixing efficiency of the composition and ethylene can be increased and the influence of mass transfer limitation can be reduced, the activity of the reaction can be improved.

In addition, the ethylene oligomerization apparatus of the present invention does not require an internal device such as a stirrer and a vacuum dispersion tube in the ethylene oligomerization reactor can reduce the fouling phenomenon due to the polymer. Thus, the reactor can be cleaned in a short time without additional cleaning operations, thereby increasing the period of stopping the device. In addition, since there is no use of the stirrer, there is an advantage that the installation space becomes small and the equipment installation cost is reduced.

1 is a flowchart of a method for oligomerization of ethylene according to one embodiment of the present invention.
2 is a block diagram of an oligomerization apparatus of ethylene according to an embodiment of the present invention.
Figure 3 is an enlarged view of the ejector coupled to the venturi tube according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail to aid in understanding the present invention. The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best describe their invention. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

As used herein, the terms "comprise", "comprise" or "have" are intended to indicate that there is a feature, number, step, component, or combination thereof, that is, one or more other features, It should be understood that it does not exclude in advance the possibility of the presence or addition of numbers, steps, components, or combinations thereof.

Throughout this specification, "catalyst system", "catalyst composition" or "catalyst system" means a three component comprising a transition metal source, a ligand compound and a promoter, or alternatively, two components of the transition metal compound and a promoter It means a state which can be added simultaneously or in any order to obtain an active catalyst composition. Three or two components of the catalyst composition may be added in the presence or absence of a solvent and a monomer, and the three terms may be used interchangeably.

As used herein, the term 'oligomerization' means that the olefin is small polymerized. Depending on the number of olefins to be polymerized, it is called trimerization and tetramerization, which is collectively called multimerization. In particular, it is meant herein to selectively prepare 1-hexene and 1-octene which are the main comonomers of LLDPE from ethylene.

In the present specification, the hydrocarbyl group refers to all compounds consisting of only carbon and hydrogen, and examples thereof include an alkyl group, an aryl group, an alkenyl group, a cycloalkyl group, and the like. As long as there is no, it can mean both straight and branched chain, it can mean both unsubstituted and substituted. For example, a group which is an alkyl group having 1 to 20 carbon atoms may mean methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, pentyl group, isopentyl group, neopentyl group, etc. The aryl group having 6 to 20 carbon atoms includes, for example, a phenyl group, a naphthyl group, an anthracenyl group, and the like, but is not limited thereto.

In this specification, an alkylaryl group means an aryl group having at least one alkyl group as a substituent, and an arylalkyl group means an alkyl group having at least one aryl group as a substituent.

In the present specification, the hetero element refers to N, O, S, and P, and the heterohydrocarbyl group may mean a hydrocarbyl group including one or more hetero atoms. That is, a heteroalkyl group may mean that any one carbon of the constituent carbons of the alkyl group is substituted with a hetero atom, or a hetero atom is included as a substituent, and the heteroaryl group, like a pyridyl group, any one of the carbons in the aromatic ring is a hetero atom. It may mean substituted. The same may also apply to other heteroarylalkyl groups, heteroalkylaryl groups, heteroalkenylaryl groups, and the like.

Hereinafter, the oligomerization apparatus and method of ethylene of this invention are explained in full detail.

Method for oligomerization of ethylene

The oligomerization method of ethylene of the present invention comprises a first step of preparing a catalyst composition by mixing a catalyst mixture comprising a catalyst and a promoter for 1 to 10 minutes; A second step of injecting the catalyst composition and ethylene into the reactor through an ejector in which a venturi tube is coupled; A third step of carrying out an ethylene oligomerization reaction in the reactor; A fourth step of discharging 50 to 90% by weight of the reaction solution in the reactor from the reactor during the oligomerization reaction; A fifth step of removing heat by passing the reaction solution from the reactor through a heat exchanger; And a sixth step of mixing the defrosted reaction solution with the reaction solution in the reactor.

1 is a flow chart of the oligomerization method of ethylene according to an embodiment of the present invention, Figure 2 is a block diagram of a device for oligomerization of ethylene according to an embodiment of the present invention.

Referring to FIGS. 1 and 2, in one embodiment, an oligomerization method of ethylene prepares a catalyst composition by mixing a catalyst mixture including a catalyst and a cocatalyst using an in-line mixer 1, and mixes the catalyst composition and ethylene. After injection into the reactor (2) through the ejector (4) coupled to the turing tube proceeds the ethylene oligomerization (oligomerization) reaction, the reaction complete solution is completed from the reactor (2).

Since the synthesis | combination of an alpha olefin oligomer is exothermic reaction by the low polymerization reaction which uses alpha olefins, such as ethylene, as a raw material, it advances, cooling the reactor 2. As shown in FIG. To this end, the reactor 2 is further provided with a coolant (or refrigerant) jacket 21 on the outside. That is, the cooling water (or refrigerant) jacket 21 cools the reactor 2 in which the exothermic reaction proceeds. And the reactor 2 is provided with a relief valve 22 at the top, it is possible to safely maintain the internal pressure at the set pressure during the synthesis reaction. Optionally, a coil may be included inside the reactor to remove reactor heat (not shown).

For example, the oligomerization method of ethylene may include a first step (ST1) of preparing a catalyst composition by mixing a catalyst mixture including a catalyst and a promoter for 1 to 10 minutes; A second step (ST2) of injecting the catalyst composition and ethylene into the reactor through an ejector in which a venturi tube is coupled; A third step (ST3) of carrying out an ethylene oligomerization reaction in the reactor; A fourth step (ST4) of discharging 50 to 90% by weight of the reaction solution in the reactor from the reactor; A fifth step (ST5) of removing heat by passing the reaction solution from the reactor through a heat exchanger; And a sixth step (ST6) of mixing the preheated reaction solution with the reaction solution in the reactor.

As an example, the first step ST1 may be performed using the inline mixer 1. In-line mixer is a system that mixes the raw material and the liquid solvent to pass the contents between the minute interval between the stator and the rotor rotating at high speed to reduce the cohesion between molecules and to produce a dispersion and grinding effect. Therefore, the in-line mixer is capable of stable mixing, there is an advantage that the work efficiency is increased because the dispersion, grinding and emulsification proceeds by circulating the contents.

This allows the catalyst and cocatalyst to be uniformly mixed so that the selectivity of the catalyst can remain the same. Therefore, there is an effect that the activity of the catalyst is improved and the production of the polymer other than the oligomer is minimized.

The inline mixer usable in the present invention is a static or dynamic inline mixer, preferably a static mixer.

In the present invention, the mixing is performed for 1 to 20 minutes, preferably 1 to 10 minutes, preferably 1 to 5 minutes, most preferably 1 to 2 minutes can be performed.

When the mixing is performed in less than 1 minute, chemical bonds such as coordination bonds between the catalyst and the promoter may not be well achieved, resulting in scale. In addition, when the mixing is performed for more than 10 minutes, deterioration of the catalyst may occur, resulting in a decrease in stability and a decrease in product productivity per catalyst.

Injecting the catalyst composition and ethylene in the second step (ST2) is characterized in that it is carried out through the ejector 221 coupled to the venturi tube 222 located on the upper portion of the reactor (2). The ejector 221 is equipped with a nozzle, the nozzle serves to increase the speed by reducing the injection cross-sectional area of the catalyst composition supplied into the reactor at high pressure. As a result, the catalyst composition is introduced into the reactor while forming a high velocity jet, and this high inlet velocity has an effect of subsequently drawing the catalyst composition and ethylene.

As an example, in the second step ST2, the catalyst composition may be supplied into the reactor at an injection speed of 1 to 10 m / s, preferably 1 to 3 m / s.

In addition, the ethylene can be fed into the reactor at a spray rate of 1 to 10 m / s, preferably 1 to 3 m / s.

The diameter of the nozzle may vary depending on the size of the reactor, and generally 0.5 to 5 mm.

In addition, the ejector 221 is coupled to the venturi tube 222, the venturi tube 222 is an inlet 222a formed in the form of a straight pipe and a diffusion portion 222b consisting of a tube extending downward. Inlet 222a is coupled to the ejector 221 and the diameter of the inlet 222a is the same as the diameter of the inlet of the diffusion 222b and is smaller than the diameter of the outlet of the diffusion 222b. small. At the same time, it is preferable that the outlet direction of the diffusion part 222b faces the lower part of the reactor. The diameter of the inlet 222a is preferably 0.2 to 1000 mm, the diameter of the inlet of the diffuser 222b is the same as the diameter of the inlet 222a, and the diameter of the outlet of the diffuser 222b is the diffuser 222b. It is preferable that it is 1.0 to 10 times the inlet diameter. In addition, the length of the diffusion part 222b is preferably 0.1 to 10 times the length of the inlet part 222a, and the length of the entire venturi tube in which the inlet part 222a and the diffusion part 222b are combined is 0.01 of the reactor body length. It is preferable that they are times-0.95 times, and it is more preferable that they are 0.05 times-0.75 times.

The catalyst composition and ethylene are injected into the reactor through the ejector 221 and the venturi tube 222 coupled thereto. The catalyst composition and ethylene thus injected form the microbubbles due to turbulence and thus inside the reactor. Because of the spraying, the contact surface area is large, and the mixing efficiency is greatly increased.

As an example, the catalyst composition injected through the ejector 221 to which the venturi tube 222 is coupled may be introduced into the reactor in the form of microbubbles having an average particle diameter of 50 to 500 μm, preferably 100 to 200 μm.

As an example, ethylene injected through the ejector 221 to which the venturi tube 222 is coupled may be introduced into the reactor in the form of microbubbles having an average particle diameter of 50 to 500 μm, preferably 100 to 200 μm.

One embodiment of the present invention may not include an agitator and a vacuum sparger. In the present invention, since the mixing of the catalyst composition and ethylene is efficiently performed by using the ejector 221 to which the venturi tube 222 is coupled, a separate stirrer or a vacuum dispersion tube is not required. As such, when there is no separate internal device, fouling by the stirrer may be prevented in the reactor 2.

Therefore, the generation of scale inside the reactor 2 can be reduced. In addition, since the reactor 2 can be cleaned in a short time without additional cleaning operation, the period for stopping the apparatus can be increased. That is, the running time of the device is increased. Moreover, since no stirrer is used, installation space becomes small and apparatus installation cost becomes small.

In the third step (ST3), the injected catalyst composition and ethylene remain in the reactor 2 for a predetermined time to proceed with the ethylene oligomerization reaction.

In the third step (ST3), a homogeneous liquid phase reaction in the presence or absence of an inert solvent using a conventional apparatus and contact technology with the catalyst composition, slurry reaction in which the catalyst composition is not partially or completely dissolved, 2 A phase liquid / liquid reaction, or a bulk phase reaction or a gas phase reaction in which the product olefins act as the main medium, is possible, and a homogeneous liquid phase reaction is preferred.

As an example, the third step ST3 may be a temperature of about 5 ° C. to about 200 ° C., preferably about 30 ° C. to about 150 ° C., more preferably 45 to 100 ° C., more preferably 45 to 65 ° C., or It may be carried out at a temperature of 45 to 60 ℃.

In addition, the third step ST3 may be performed at a pressure of about 1 bar to about 300 bar, preferably at a pressure of about 2 bar to about 150 bar, more preferably 45 to 65 bar.

The range of the temperature and pressure conditions may be the conditions of the family register for the ethylene oligomerization reaction, when the ethylene oligomerization reaction is performed within the temperature range and pressure range, the selectivity for the desired alpha-olefin is excellent, the amount of by-products This reduces costs, increases efficiency and reduces costs.

In the third step ST3, the ethylene and the oligomerization catalyst composition are introduced into the reactor while the reaction solvent is introduced into the reactor, or the catalyst composition is introduced into the reactor while the reaction solvent and ethylene are introduced into the reactor. May be initiated. In addition, the catalyst composition may include a solvent.

The reaction solvent is one selected from the group consisting of benzene, toluene, xylene, cumene, chlorobenzene, dichlorobenzene, heptane, cyclohexane, methylcyclohexane, methylcyclopentane, n-hexane, 1-hexene, 1-octene It may be abnormal.

In addition, the oligomerization method of ethylene may include obtaining a composition including 1-hexene and 1-octene as a product after the third step (ST3). Obtaining such a product may be a step of separating the products produced by the oligomerization reaction of ethylene through a device such as a distillation column.

In the separation process, the energy required for separation may vary depending on the type of the solvent used in the ethylene oligomerization reaction, and in general, a compound having a boiling point between the boiling point of 1-hexene and 1-octene as a main product. May be used as the reaction solvent. In this case it can be quite advantageous in terms of separation energy.

The fourth step ST4 is a step in which 50 to 90% by weight of the reaction solution in the reactor is sent out of the reactor during the oligomerization reaction of the third step ST3.

In the fifth step (ST5), the solution during the reaction exits the reactor 2 and passes through the first pipe 31 to the heat exchanger (3). The heat exchanger (3) is provided on the outside of the reactor (2) is connected to the first pipe line (31) to remove the heat entering the reaction medium solution, connected to the second pipe line (32) the reaction medium solution Is fed back into the reactor (2).

For example, the heat exchanger 3 has a high temperature of cooling water toward the side of the second conduit 32 where low temperature cooling water flows into the first pipe line 31 through which the high temperature reaction solution flows in and a low temperature of the reaction solution flows out. Acts as a heat exchanger.

The first pipe 31 is provided with a strainer or filter 311 and the circulation pump 312 to filter the reaction solution from the reactor 2 through the first pipe 31 to supply to the heat exchanger (3). . The second conduit 32 supplies the reaction medium solution, which has been deoxidized via the heat exchanger 3, by the pressure of the circulation pump 312 to the reactor 2.

In the sixth step ST6, the reaction intermediate solution dehumidified by the heat exchanger 3 is mixed with the reaction solution inside the reactor 2 again.

In addition, the oligomerization method of ethylene of the present invention further includes a seventh step (ST7) of outputting a reaction solution containing alpha-olefins such as 1-hexene and 1-octene prepared by the oligomerization reaction in the reactor. can do.

As an example, before the reaction medium solution from the reactor of the fourth stage is introduced into the heat exchanger (3), the reaction completion solution and ethylene containing the alpha-olefin may be separated through the branched pipe (33).

Alternatively, the reaction completed solution including alpha-olefin and ethylene may be separated through the branched conduit 34 before the reacted intermediate solution, which has been passed through the heat exchanger 3, is introduced into the reactor again. In the process configuration, only one of the conduit 33 or the conduit 34 may be selected. Preferably, the reaction completed solution and ethylene are separated through the conduit 33.

In addition, it is possible to perform a step of separating and producing a composition comprising 1-hexene and a composition comprising 1-octene from the separated reaction completed solution through a device such as a distillation column. In addition, the separated ethylene can be introduced back into the reactor for reuse.

Oligomerization Catalyst Composition

In the method for oligomerization of ethylene of the present invention, any conventionally known catalyst can be used, and is not particularly limited. As one example, the catalyst composition of the present invention comprises a ligand compound; Transition metal compounds; And promoters.

In order to increase the selectivity to the linear alpha olefin and to increase the multimerization activity, the molar ratio of the ligand: metal of the transition metal compound: aluminum or boron of the promoter is about 1: 1: 1 to 10: 1: 10,000, preferably about 0.5: 1: 1 to about 10: 1: 10,000, more preferably about 0.5: 1: 100 to about 5: 1: 3,000.

Hereinafter, a ligand compound constituting the catalyst composition; Transition metal compounds; And look at the configuration of the promoter in more detail.

Ligand Compound

According to one embodiment of the present specification, a ligand compound including one or more diphosphine moieties may be represented by the following Chemical Formula 1.

[Formula 1]

In Formula 1, A is N, P, As or Sb,

When the ligand compound includes one diphosphine moiety, * denotes an aliphatic hydrocarbon group of C 1 to C 20, a heteroaliphatic hydrocarbon group of C 2 to C 20, an alicyclic hydrocarbon group of C 3 to C 20, and a hetero group of C 3 to C 20 At least one group selected from the group consisting of an alicyclic hydrocarbon group, a C6-C20 aromatic hydrocarbon group and a C6-C20 heteroaromatic hydrocarbon group,

When the ligand compound includes two or more diphosphine moieties, * is a diphosphine moiety linked through a linking group, and the linking group is a C 2 to C 20 aliphatic hydrocarbon group, C 2 to C 20 heteroaliphatic hydrocarbon group, At least one member selected from the group consisting of C3 to C20 alicyclic hydrocarbon group, C3 to C20 heteroalicyclic hydrocarbon group, C6 to C30 aromatic hydrocarbon group, and C6 to C30 heteroaromatic hydrocarbon group,

R1 to R4 are each independently C6 ~ C20 aryl group or C7 ~ C20 alkylaryl group.

Transition metal compound

In the catalyst composition used in the oligomerization reaction of ethylene of the present invention, the transition metal of the transition metal compound is preferably chromium. As an example, the transition metal compound may be an organic or inorganic chromium compound having an oxidation state of chromium of 0 to 6, for example, a chromium metal or a compound in which any organic or inorganic radical is bonded to chromium. Here, the organic radical may be alkyl, alkoxy, ester, ketone, amido radical, etc. having 1 to 20 carbon atoms per radical. The inorganic radicals may be halides, sulfates, oxides, and the like.

Preferably, the chromium source is chromium (III) acetylacetonate, chromium trichloride tristetrahydrofuran, chromium (III) -2-ethylhexanoate, chromium (III) tris (2,2,6,6-tetramethyl At least one selected from the group consisting of -3,5-heptanedionate), chromium (III) benzoylacetonate, chromium (III) hexafluoro-2,4-pentanedionate and chromium (III) acetate hydroxide Can be.

Promoter

In the catalyst composition used in the oligomerization reaction of ethylene of the present invention, the promoter may be at least one selected from the group consisting of compounds represented by Formulas 2 to 4.

[Formula 2]

R _5- [Al (R ₆ ) -O] cR ₇

In Chemical Formula 2, R ₅ to R ₇ are each independently hydrogen, halogen, C 1 to C 20 hydrocarbyl group, or C 1 to C 20 hydrocarbyl group substituted with halogen, c is an integer of 2 or more,

[Formula 3]

D (R ₈ ) ₃

In Formula 3, D is aluminum or boron, R ₈ are each independently hydrogen, halogen, C 1 to C 20 hydrocarbyl group or C 1 to C 20 hydrocarbyl group substituted with halogen,

[Formula 4]

[LH] ⁺ [Q (E) ₄ ] ^-

In Chemical Formula 4,

L is a neutral Lewis base, [LH] ⁺ is Bronsted acid, Q is boron or aluminum in the +3 type oxidation state, each E is independently at least one hydrogen atom is a halogen, a C1-C20 hydrocarbyl group, It is a C6-C20 aryl group or C1-C20 alkyl group unsubstituted or substituted by the alkoxy functional group or the phenoxy functional group.

As the compound represented by Formula 2, for example, modified methyl aluminoxane (MMAO), methyl aluminoxane (MAO), ethyl aluminoxane, isobutyl aluminoxane, butyl aluminoxane and the like.

As the alkyl metal compound represented by the formula (3), for example, trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, dimethylisobutylaluminum, dimethylethylaluminum and diethyl Chloro aluminum, triisopropyl aluminum, tri-s-butyl aluminum, tricyclopentyl aluminum, tripentyl aluminum, triisopentyl aluminum, trihexyl aluminum, ethyl dimethyl aluminum, methyl diethyl aluminum, triphenyl aluminum, tri-p- Tolyl aluminum, dimethyl aluminum methoxide, dimethyl aluminum ethoxide, trimethyl boron, triethyl boron, triisobutyl boron, tripropyl boron, tributyl boron and the like.

Examples of the compound represented by the formula (4) include triethylammonium tetraphenylboron, tributylammonium tetraphenylboron, trimethylammonium tetraphenylboron, tripropylammonium tetraphenylboron, trimethylammonium tetra (p-tolyl) boron, Tripropylammonium tetra (p-tolyl) boron, triethylammonium tetra (o, p-dimethylphenyl) boron, trimethylammonium tetra (o, p-dimethylphenyl) boron, tributylammonium tetra (p-trifluoromethylphenyl) Boron, trimethylammonium tetra (p-trifluoromethylphenyl) boron, tributylammoniumtetrapentafluorophenylboron, N, N-diethylaniliniumtetraphenyl boron, N, N-diethylaniliniumtetraphenylboron, N , N-diethylanilinium tetrapentafluorophenylboron, diethylammonium tetrapentafluorophenylboron, triphenylphosphonium tetraphenylboron, trimethylphosphonium tetraphenylboron, triethylammo Tetraphenylaluminum, tributylammonium tetraphenylaluminum, trimethylammonium tetraphenylaluminum, tripropylammonium tetraphenylaluminum, trimethylammonium tetra (p-tolyl) aluminum, tripropylammonium tetra (p-tolyl) aluminum, triethylammonium tetra ( o, p-dimethylphenyl) aluminum, tributylammonium tetra (p-trifluoromethylphenyl) aluminum, trimethylammonium tetra (p-trifluoromethylphenyl) aluminum, tributylammonium tetrapentafluorophenylaluminum, N, N- Diethylanilinium tetraphenylaluminum, N, N-diethylanilinium tetraphenylaluminum, N, N-diethylanilinium tetrapentafluorophenylaluminum, diethylammonium tetrapentafluorophenylaluminum, triphenylphosphonium tetra Phenyl aluminum, trimethyl phosphonium tetraphenyl aluminum, triphenyl carbonium tetra phenyl boron, triphenyl carbonium te La phenyl aluminum, triphenyl carbonyl titanium tetra (p- methylphenyl to triple) may phenylboronic the like as boron, triphenyl carbonyl titanium tetra-pentafluoropropane.

As an example, aluminoxane may be preferably used as a cocatalyst of the catalyst composition, and more preferably methylaluminoxane (MAO) or modified methylaluminoxane (MMAO) may be used.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited only to them.

Example 1

Preparation of Catalyst Composition

A transition metal compound using chromium (Cr) as the transition metal was prepared as a catalyst for ethylene oligomerization. Methylcyclohexane as a solvent and the catalyst were mixed to prepare a solution of 0.05 to 0.5 mM, and mMAO (8.6 wt% isoheptane solution) was prepared as a promoter. A solution and a cocatalyst in which the solvent and the catalyst were mixed were added to a glass jar, and mixed for 5 to 20 minutes to prepare a catalyst composition.

Ethylene oligomerization reaction

A 600 ml reactor was prepared and vacuumed at 120 ° C. for 2 hours, then the temperature was lowered to 60 ° C. and the interior was replaced with argon. The reactor is equipped with an ejector in which a venturi tube is coupled to the top, and an apparatus is used in which there is no separate stirrer inside the reactor. Then 1 ml (Al / Cr = 1200) of 140 g of methylcyclohexane as solvent and MMAO (8.6 wt%, isoheptane solution) as cocatalyst were injected and 5 ml of 0.5 mM solution mixed with the catalyst composition ( 2.5umol) was injected into the reactor at an injection speed of 5 to 7 m / s using an ejector coupled with a Venturi tube.

Thereafter, the ethylene and the reaction product were circulated using a circulating pump, filled with 60 ethylene at an injection rate of 5 to 7 m / s into the reactor, and the temperature in the reactor was controlled (T <2 ° C.). After slowly venting the unreacted ethylene, 1 ml of nonane (GC internal standard) was added thereto. Thereafter, a small portion of the liquid portion of the reactor was quenched with water, the organic layer was filtered with a PTFE syringe filter, and the resulting polymer was separated and dried. In addition, the organic layer portion was removed with MgSO ₄ to remove residual moisture, and the composition of the organic layer was confirmed by GC-MS, and it was confirmed that the mixture was an alpha-olefin polymer according to the Schultz-Flory distribution. A mixture of methanol and diluted HCl was added to the remaining reaction solution, followed by stirring to analyze the amount of solids.

Comparative Example 1

The experiment was the same as in Example 1 except that a reactor equipped with a stirrer was used instead of an ejector having a Venturi tube coupled to the inside of the reactor.

Comparative Example 2

Experiments were carried out in the same manner as in Example 1, except that the catalyst composition in which the catalyst and the co-catalyst were mixed was not separately prepared and sprayed separately into the reactor.

Comparative Example 3

The experiment was the same as in Example 1, except that the catalyst composition was prepared by mixing the catalyst and the promoter for 20 minutes.

Comparative Example 4

The experiment was carried out in the same manner as in Example 1 except that the temperature inside the reactor was 70 ° C. and ethylene was injected so that the pressure inside the reactor was 40 bar.

Experimental Example

The analysis results of the Examples and Comparative Examples are shown in Table 1 below.

Reaction temperature (℃) Reaction pressure (bar) Reaction time (min) Catalyst activity (%) compared to Comparative Example 1 Oligomer Content (wt%) Solid content (wt%) C6 C8 C10 + Example 1 60 60 15 95 20-25 60-65 5-10 0-0.5 Comparative Example 1 60 60 15 100 20-25 60-65 5-10 0.5-1 Comparative Example 2 60 60 15 80 20-25 60-65 5-10 1-1.5 Comparative Example 3 60 60 15 70 20-25 60-65 5-10 1-1.5 Comparative Example 4 70 40 15 50 35-40 50-55 5-10 0-0.5

As shown in Table 1, the catalyst and the cocatalyst were mixed for 1 to 10 minutes to prepare a catalyst composition, and the ethylene oligomer was prepared by injecting it into a reactor using an ejector having a venturi tube. In the case of Example 1, it was confirmed that the solid by-product generation was significantly reduced compared to the comparative example without lowering the catalytic activity.

On the other hand, the catalyst composition was prepared, but in Comparative Example 1 using a reactor equipped with a stirrer as in the prior art without using an ejector in which a venturi tube was combined, it was found that the produced solid content was rather high to prevent the formation of by-products. Could. In addition, in Comparative Example 2, in which the same reactor as in Example 1 was used, but the catalyst and the promoter were sprayed separately without mixing in advance, the catalyst activity was not increased because the catalyst was not pre-mixed to activate the catalyst. It was confirmed that the problem of lowering and increasing solid production amount. This is because the oligomerization reaction proceeds in a state in which the catalyst is not sufficiently activated because the catalyst and the catalyst are directly introduced into the reactor without mixing the promoter and the catalyst in advance.

In addition, the mixing time is also an important factor when preparing the catalyst composition, especially when the catalyst and the promoter is mixed for 20 minutes in excess of 1 to 10 minutes as in Comparative Example 3, not only increases the solid content Catalyst activity has also been shown to decrease. In addition, the catalyst activity was found to be reduced by half compared to the reference.

On the other hand, in the case of Comparative Example 4, since the reaction temperature is 65 ℃ or more and the reaction pressure is lower than 45 bar, it was shown that the catalytic activity is somewhat reduced. This demonstrates that the oligomerization reaction temperature and pressure are also factors that affect catalyst activity.

Through the above results, when the catalyst composition is prepared in advance by mixing the catalyst and the cocatalyst, and simultaneously injected into the reactor by using an ejector with a venturi tube, it is possible to efficiently maintain the catalyst activity while preventing the solid formation It was confirmed that the ethylene oligomerization reaction can be carried out. In this method, since the ejector is used to mix the catalyst composition and ethylene, a separate agitator is not installed in the reactor, which can reduce the fouling caused by the internal device and increase the shutdown period. will be.

Claims (12)

A first step of preparing a catalyst composition by mixing a catalyst mixture including a catalyst and a promoter for 1 to 10 minutes;
A second step of injecting the catalyst composition and ethylene into the reactor through an ejector in which a venturi tube is coupled;
A third step of carrying out an ethylene oligomerization reaction in the reactor;
A fourth step of discharging 50 to 90% by weight of the reaction solution in the reactor from the reactor during the oligomerization reaction;
A fifth step of removing heat by passing the reaction solution from the reactor through a heat exchanger; And
And a sixth step of mixing the preheated reaction solution with the reaction solution in the reactor.
The method according to claim 1,
Wherein said mixing in said first step is carried out using an inline mixer.
The method according to claim 1,
In the first step, the mixing is carried out for 1 to 5 minutes, oligomerization method of ethylene.
The method according to claim 1,
In the second step, the ejector is a nozzle-equipped ejector, oligomerization method of ethylene.
The method according to claim 1,
In the second step, the catalyst composition is oligomerization method of ethylene is fed into the reactor at a spray rate of 1 to 10 m / s.
The method according to claim 1,
In the second step, the ethylene is oligomerization method of ethylene is fed into the reactor at a spray rate of 1 to 10 m / s.
The method according to claim 1,
In the second step, the catalyst composition and ethylene injected through the ejector in which the venturi tube is coupled are introduced into the reactor in the form of microbubbles having an average particle diameter of 50 to 500 µm.
The method according to claim 1,
The third step is carried out under a temperature of 5 to 200 ℃ and pressure of 1 to 300 bar, oligomerization method of ethylene.
The method according to claim 1,
The third step is carried out at a temperature of 45 to 65 ℃ and pressure of 45 to 65 bar, oligomerization method of ethylene.
The method according to claim 1,
Ethylene oligomerization method further comprises a seventh step of sending out the reaction solution containing the alpha-olefin prepared by the oligomerization reaction in the reactor.
An inline mixer for preparing a catalyst composition by mixing a catalyst mixture comprising a catalyst and a promoter;
An ejector having a venturi tube coupled as a passage for injecting the catalyst composition and ethylene into the reactor, and a reactor for performing an ethylene oligomerization reaction with the catalyst composition and ethylene injected therethrough; And
A heat exchanger provided outside the reactor and connected to a first pipe line to remove heat of the reaction solution containing ethylene and the catalyst composition circulated after being discharged from the reactor after staying in the reactor;
Oligomerization apparatus of ethylene comprising a.
The method according to claim 11,
The oligomerization apparatus of ethylene which does not contain a stirrer and a vacuum dispersion tube in the said oligomerization reactor.

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