CN109701645B

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Publication number: CN109701645B
Application number: CN201711011297.1A
Authority: CN
Inventors: 郑明芳; 吴红飞; 栗同林; 刘珺
Original assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Current assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Priority date: 2017-10-26
Filing date: 2017-10-26
Publication date: 2021-12-21
Anticipated expiration: 2037-10-26
Also published as: CN109701645A

Abstract

The invention relates to a catalyst composition, which comprises a chlorinated 2-acyl-1, 10-phenanthroline amine iron (II) complex shown in a formula I and an aluminum-containing cocatalyst;

wherein R' in the formula is hydrogen or C₁‑C₅An alkyl group; r₁‑R₅Each independently is hydrogen, C₁‑C₆Alkyl, halogen, C₁‑C₆Alkoxy or nitro. The invention also relates to the use of said catalyst composition. The catalyst composition of the invention has high activity; meanwhile, the aromatic solvent is not used in the polymerization reaction, and a high-quality product can be obtained.

Description

Catalyst composition and application thereof

Technical Field

The present invention relates to a catalyst composition for oligomerization of ethylene. The invention also relates to an application of the catalyst composition in an ethylene oligomerization process.

Background

Ethylene oligomerization is one of the most important reactions in the olefin polymerization industry. Through oligomerization, cheap small-molecular olefins can be converted into products with high added value. The ethylene oligomerization product, linear alpha-olefin (LAO), is an important organic chemical raw material. For example, LAO C4-C8 is used as an important organic raw material and a chemical intermediate, and is mainly applied to the field of producing high-quality Polyethylene (PE). The Linear Low Density Polyethylene (LLDPE) produced by copolymerizing 1-hexene or 1-octene with ethylene can obviously improve various properties of PE, in particular can obviously improve the mechanical property, optical property, tear strength and impact strength of polyethylene, and the product is very suitable for the fields of packaging films, agricultural covering films for greenhouses, sheds and the like. LAO C10-C30 can be used as additives for preparing household cleaning agents, flotation agents, emulsifiers, lubricating components for refrigerators and lubricating components for drilling fluids, plasticizers, various additives, low-viscosity synthetic oils, polymers and copolymers, petroleum and petroleum product additives, higher alkylamines, higher organoaluminum compounds, higher alkylaryl hydrocarbons, higher fatty alcohols and fatty acids, epoxides, heat carriers, and the like. Adhesives, sealants and coatings can also be synthesized on the basis of LAO C20-C30. In recent years, with the continuous development of the polyolefin industry, the worldwide demand for α -olefins has rapidly increased. Wherein the majority of the alpha-olefin is prepared by ethylene oligomerization.

Since the last 70 s, the research on the polymerization and oligomerization of olefins catalyzed by transition metal complexes has been receiving the attention of scientists, and efforts have been made to research new catalysts and improve the existing catalysts, so as to improve the activity of the catalysts and the selectivity of catalytic products. Among the most developed and concentrated researches on the nickel-based cationic catalytic system were conducted in the earliest research, such as U.S. Pat. Nos. 3686351 and 3676523 reported earlier, and the Shell SHOP technology based on the technology of the above patents. The O-P bridging ligand is involved in the Shell company SHOP process, but the catalyst contains toxic organophosphorus groups, and the synthesis steps are complex and the stability is poor. Subsequently, many patents such as O-O, P-N, P-P and N-N type complex nickel catalysts have been developed, such as JP11060627, WO9923096, WO991550, CN1401666, CN1769270, etc. However, the catalysts obtained from the above patents suffer from the general disadvantage of relatively complicated preparation processes. Other catalysts are chromium, zirconium and aluminum, Brookhart groups (Brookhart, M et al, J.Am.chem.Soc.,1998,120, 7143-.

In the field of olefin polymerization, particularly metallocene catalysis, alkoxy aluminum such as Methyl Aluminoxane (MAO) or Modified Methyl Aluminoxane (MMAO) is generally used as a cocatalyst, and the price of MAO is dozens of times higher than that of other alkyl aluminum, so that the catalyst has long been a main bottleneck for restricting the industrialization of the field. In addition, MAO is very difficult to dissolve in alkane solvents, so commercially available MAO is generally an aromatic hydrocarbon solution such as toluene, which causes aromatic hydrocarbons to remain in the reaction product, and seriously affects the product quality. While the use of co-polymer grade a-olefins in the preparation of polyethylene tends to severely limit their aromatic content.

There is no doubt that there is still a need for a novel catalyst with excellent comprehensive performance in the field of olefin oligomerization. Attention is paid to how to obtain a cocatalyst with lower cost and more excellent performance, so that an ethylene oligomerization catalyst with high activity and selectivity is developed, and the attention is paid to the industry.

Disclosure of Invention

The inventors of the present application have found a catalyst composition when studying an ethylene oligomerization catalyst. The catalyst composition is used for catalyzing ethylene oligomerization reaction and has the advantages of high activity and high selectivity.

According to one aspect of the present invention, there is provided a catalyst composition comprising a 2-acyl-1, 10-phenanthroline iron (II) chloride complex of formula I and an alkane solution containing an aluminum cocatalyst;

wherein R' in the formula is hydrogen or C₁-C₅An alkyl group; r¹-R⁵Each independently is hydrogen, C₁-C₆Alkyl, halogen, C₁-C₆Alkoxy or nitro;

the preparation method of the alkane solution containing the aluminum cocatalyst comprises the following steps:

step a: reacting water with an aromatic hydrocarbon solution of aluminum alkyl; wherein the general formula of the alkyl aluminum is R₁R₂R₃Al，R₁、R₂And R₃Same or different, independently selected from C₁-C₂₀Alkyl groups of (a);

step b: reacting the solution obtained after the reaction in the step a with an aromatic hydrocarbon solution of aluminoxane; alkyl groups and R in said aluminoxanes₁、R₂And R₃Different;

step c: and c, reacting the solution obtained after the reaction in the step b with water, removing aromatic hydrocarbon, and adding alkane to obtain an alkane solution containing the aluminum cocatalyst.

The catalyst composition has the advantages of simple preparation, low cost, high activity and high selectivity, and can effectively catalyze the ethylene oligomerization reaction.

The catalyst composition according to the present invention, the preparation method thereof comprises: an alkane solution containing an aluminum promoter is first prepared by a process comprising the steps of:

step c: b, reacting the solution obtained after the reaction in the step b with water, removing aromatic hydrocarbon, and adding alkane to obtain an alkane solution containing the aluminum cocatalyst;

then mixing the prepared alkane solution containing the aluminum cocatalyst with the complex shown in the formula I, or mixing the prepared alkane solution containing the aluminum cocatalyst with the complex shown in the formula I when in use.

According to some preferred embodiments of the invention, in the general formula of the aluminum alkyl, R₁、R₂And R₃Same or different, independently selected from C₁-C₁₀Alkyl group of (1). In some preferred embodiments, R₁、R₂And R₃And the same is selected from one of methyl, ethyl, n-propyl, isopropyl, butyl, isobutyl, tert-butyl and n-pentyl.

According to some preferred embodiments of the present invention, the aluminoxane is selected from at least one of methylaluminoxane and ethylaluminoxane.

According to some preferred embodiments of the present invention, the step a comprises adding water to the triisobutylaluminum aromatic hydrocarbon solution at a low temperature, stirring the mixture for a certain time, heating the mixture to reflux, and then cooling the mixture to room temperature for standby. Preferably, step a comprises reacting the water with an aromatic hydrocarbon solution of an aluminum alkyl at-20 ℃ to 10 ℃, such as-20 ℃ to 0 ℃, such as-10 ℃ to 0 ℃ for 0.1h to 1h, and then heating under reflux for 0.1h to 1 h. In some preferred embodiments, the molar ratio of water to the aluminum alkyl in step a is (0.5-1): 1.

According to some preferred embodiments of the present invention, the step b comprises mixing the product of the step a with a methylaluminoxane aromatic hydrocarbon solution, heating the mixture to reflux for reaction, and cooling the mixture to room temperature for later use. Preferably, the solution obtained after the reaction of step a is mixed with an aromatic hydrocarbon solution of aluminoxane at 5 ℃ to 40 ℃, preferably at room temperature, and then heated under reflux for 0.1h to 1 h. In some preferred embodiments, the molar ratio of aluminoxane to aluminum alkyl in step b is (0.1-3):1, preferably (0.5-1): 1.

According to some preferred embodiments of the present invention, the step c comprises adding water to the aromatic hydrocarbon solution in the step b at a low temperature, stirring for a certain time, heating to reflux, and cooling to room temperature; preferably, the solution obtained after the reaction in step b is reacted with water at-20 ℃ to 10 ℃, preferably-10 ℃ to 0 ℃ for 0.1h to 1h, followed by heating under reflux for 0.1h to 1 h. In some preferred embodiments, the molar ratio of water to the aluminoxane in step c is (0.1-0.3): 1.

According to the invention, the reflux temperature is the boiling temperature of the aromatic hydrocarbon solvent.

In the present invention, the term "aromatic hydrocarbon" refers to hydrocarbon compounds having a benzene ring structure, such as benzene, toluene, xylene, naphthalene, and phenyl derivatives substituted with halogen, nitro or alkyl.

In the present invention, the term "alkane" refers to a saturated hydrocarbon such as at least one of pentane, hexane, heptane, cyclopentane, cyclohexane, methylcyclohexane, and the like.

According to some preferred embodiments of the invention, R is₁-R₃Likewise, for isobutyl, the isobutane content in the gaseous product, measured by gas chromatography after hydrolysis of said aluminium-containing cocatalyst, is higher than 75% by weight, preferably from 78% by weight to 94% by weight.

According to some preferred embodiments of the present invention, the method for preparing the aluminum-containing cocatalyst comprises:

a. adding water into the triisobutyl aluminum aromatic hydrocarbon solution at a low temperature, stirring and reacting for a certain time, heating and refluxing, and then cooling to room temperature for later use;

b. mixing the product obtained in the step a with methylaluminoxane aromatic hydrocarbon solution, heating for reflux reaction, and cooling to room temperature for later use;

c. and (c) adding water into the aromatic hydrocarbon solution in the step (b) at a low temperature, stirring and reacting for a certain time, heating and refluxing, cooling to room temperature, removing aromatic hydrocarbon from the mixture under reduced pressure, and adding alkane to obtain an alkane solution containing the aluminum cocatalyst. Triisobutyl aluminum is adopted in the step a, methylaluminoxane is adopted in the step b, and after the obtained aluminum-containing cocatalyst is hydrolyzed, the content of isobutane in a gas phase product is higher than 75 wt%, such as 78-94 wt%, and the balance is methane through gas chromatography detection.

According to some preferred embodiments of the catalyst composition of the present invention, the molar ratio of aluminum in the cocatalyst to iron in the procatalyst is (30-900):1, preferably (30-500):1, more preferably (50-300): 1. That is, the amount of the aluminum-containing co-catalyst is 30 to 900 moles, preferably 30 to 500 moles, and more preferably 50 to 300 moles, relative to 1 mole of the iron compound.

According to the invention, the cocatalyst has good solubility in alkane, and the catalyst composition formed by the cocatalyst and the iron complex has high activity.

According to another aspect of the present invention, there is also provided a method for using the above catalyst composition, comprising carrying out an oligomerization reaction of ethylene in the presence of the above catalyst composition. In some preferred embodiments, the oligomerization of ethylene is carried out in an organic solvent, more preferably an alkane. In the ethylene oligomerization reaction, the reaction temperature is 0-200 ℃, and preferably 0-100 ℃; the ethylene pressure is from 0.1 to 20.0MPa, preferably from 0.5 to 5.0 MPa.

According to the invention, when the catalyst composition is used, the components in the composition can be mixed and then added into a reactor, or the components in the composition can be added into the reactor respectively.

According to the invention, when the catalyst composition is reacted in alkane, an aromatic hydrocarbon solvent can be avoided, aromatic hydrocarbon residue is not left in the product, the product quality is high, and high-quality alpha-olefin monomers can be provided for the chemical industry.

According to the invention, the organic solvents used, such as alkanes, are subjected to anhydrous treatment before use; the method for the anhydrous treatment of the organic solvent may employ a method commonly used in the art.

The catalyst composition containing the cocatalyst can effectively catalyze ethylene oligomerization reaction, and the obtained ethylene oligomerization product comprises C₄、C₆、C₈、C₁₀、C₁₂、C₁₄、C₁₆、C₁₈、C₂₀、C₂₂Etc.; the selectivity of alpha-olefin can reach more than 96 percent. After the ethylene oligomerization reaction was completed, GC analysis was performed. The results show that the oligomerization activity isUp to 10⁷g·mol(Fe)^-1·h^-1The above. Therefore, the catalyst composition has better industrial application prospect and economic value.

Detailed Description

The following examples are merely illustrative of the present invention in detail, but it should be understood that the scope of the present invention is not limited to these examples.

In the present invention, the aluminum content test was performed by inductively coupled plasma emission spectroscopy (ICP Optima8300, PE corporation, usa).

In the present invention, the gas phase component after hydrolysis is detected by a Hewlett packard 5890 chromatograph. A chromatographic column: agilent HP-Al/KCL, the column length is 50m, and the inner diameter is 0.320 mm; column temperature: keeping the temperature at 100 ℃ for 10 minutes, heating the temperature to 160 ℃ at a heating rate of 10 ℃/min, keeping the temperature for 10 minutes, keeping the temperature at a sample inlet of 250 ℃ and keeping the temperature at a detector of 250 ℃; carrier gas: nitrogen, FID detector.

In the invention, the oligomerization product is detected by an Agilent 7890A chromatograph. A chromatographic column: agilent DB-1, the column length is 50m, and the inner diameter is 0.250 mm; column temperature: keeping the temperature at 30 ℃ for 3 minutes, heating the temperature to 140 ℃ at a heating rate of 20 ℃/min, heating the temperature to 300 ℃ at a heating rate of 25 ℃/min, keeping the temperature for 16 minutes, keeping the temperature of a sample inlet at 300 ℃, and keeping the temperature of a detector at 300 ℃; carrier gas: nitrogen, FID detector.

The iron complex used in the invention is self-made in patent reference (CN 102558243).

Example 1

Slowly adding 7mmol of water into 10mmol of triisobutylaluminum (1M toluene solution) in an ice bath under the protection of nitrogen, stirring for reaction for 0.5 hour, heating and refluxing for 1 hour, and then cooling to room temperature for later use; adding 10mmol of methylaluminoxane (1M toluene solution) into the solution, heating and refluxing for 1 hour, and cooling to room temperature; and slowly adding 2mmol of water into the mixed solution under ice bath, stirring for reaction for 0.5 hour, heating and refluxing for 1 hour, cooling to room temperature, removing the toluene solvent under reduced pressure, and adding a heptane solvent to obtain the cocatalyst A (1M, a heptane solution) with the total volume of the mixed solution being 20 mL.

And (3) product analysis: taking a quantitative cocatalyst A, slowly adding excessive water to decompose the cocatalyst A, and testing the content of aluminum in a liquid phase component to be 3.4 wt% by using ICP (inductively coupled plasma); gas phase composition test isobutane content 89 wt%, methane content 11 wt%.

Example 2

Slowly adding 5mmol of water into 10mmol of triisobutylaluminum (1M toluene solution) in an ice bath under the protection of nitrogen, stirring for reaction for 0.5 hour, heating and refluxing for 1 hour, and then cooling to room temperature for later use; adding 10mmol of methylaluminoxane (1M toluene solution) into the solution, heating and refluxing for 1 hour, and cooling to room temperature; and slowly adding 2mmol of water into the mixed solution under ice bath, stirring for reaction for 0.5 hour, heating and refluxing for 1 hour, cooling to room temperature, removing the toluene solvent under reduced pressure, and adding a heptane solvent to obtain a cocatalyst B (1M, a heptane solution) with the total volume of the mixed solution being 20 mL.

And (3) product analysis: taking a certain amount of cocatalyst B (same as example 1), slowly adding excessive water to decompose the cocatalyst B, wherein the content of aluminum in the liquid-phase component is 3.4 wt% by ICP test; gas phase composition test isobutane content 90 wt%, methane content 10 wt%.

Example 3

Slowly adding 10mmol of water into 10mmol of triisobutylaluminum (1M toluene solution) in an ice bath under the protection of nitrogen, stirring for reaction for 0.5 hour, heating and refluxing for 1 hour, and then cooling to room temperature for later use; adding 10mmol of methylaluminoxane (1M toluene solution) into the solution, heating and refluxing for 1 hour, and cooling to room temperature; and slowly adding 2mmol of water into the mixed solution under ice bath, stirring for reacting for 0.5 hour, heating and refluxing for 1 hour, cooling to room temperature, removing the toluene solvent under reduced pressure, and adding a heptane solvent to obtain the cocatalyst C (1M, heptane solution) with the total volume of the mixed solution being 20 mL.

And (3) product analysis: taking a certain amount of cocatalyst C (same as example 1), slowly adding excessive water to decompose the cocatalyst C, wherein the content of aluminum in the liquid-phase component is 3.4 wt% by ICP test; gas phase composition test isobutane content 78 wt% and methane content 22 wt%.

Example 4

Slowly adding 7mmol of water into 10mmol of triisobutylaluminum (1M toluene solution) in an ice bath under the protection of nitrogen, stirring for reaction for 0.5 hour, heating and refluxing for 1 hour, and then cooling to room temperature for later use; adding 10mmol of methylaluminoxane (1M toluene solution) into the solution, heating and refluxing for 1 hour, and cooling to room temperature; and slowly adding 3mmol of water into the mixed solution under ice bath, stirring for reacting for 0.5 hour, heating and refluxing for 1 hour, cooling to room temperature, removing the toluene solvent under reduced pressure, and adding a heptane solvent to obtain the cocatalyst D (1M, a heptane solution) with the total volume of the mixed solution being 20 mL.

And (3) product analysis: taking a certain amount of cocatalyst D (same as example 1), slowly adding excessive water to decompose the cocatalyst D, wherein the content of aluminum in the liquid-phase component is 3.4 wt% by ICP test; gas phase composition test isobutane content 91 wt%, methane content 9 wt%.

Example 5

Slowly adding 7mmol of water into 10mmol of triisobutylaluminum (1M toluene solution) in an ice bath under the protection of nitrogen, stirring for reaction for 0.5 hour, heating and refluxing for 1 hour, and then cooling to room temperature for later use; adding 10mmol of methylaluminoxane (1M toluene solution) into the solution, heating and refluxing for 1 hour, and cooling to room temperature; slowly adding 1mmol of water into the mixed solution under ice bath, stirring for reaction for 0.5 hour, heating and refluxing for 1 hour, cooling to room temperature, removing the toluene solvent under reduced pressure, and adding a heptane solvent to obtain a cocatalyst E (1M, heptane solution) with the total volume of the mixed solution being 20 mL.

And (3) product analysis: taking a certain amount of cocatalyst E (same as example 1), slowly adding excessive water to decompose the cocatalyst E, wherein the content of aluminum in the liquid-phase component is 3.4 wt% by ICP test; gas phase composition test isobutane content 87 wt% and methane content 13 wt%.

Example 6

Slowly adding 7mmol of water into 10mmol of triisobutylaluminum (1M toluene solution) in an ice bath under the protection of nitrogen, stirring for reaction for 0.5 hour, heating and refluxing for 1 hour, and then cooling to room temperature for later use; adding 5mmol of methylaluminoxane (1M toluene solution) into the solution, heating and refluxing for 1 hour, and cooling to room temperature; slowly adding 1mmol of water into the mixed solution under ice bath, stirring for reaction for 0.5 hour, heating and refluxing for 1 hour, cooling to room temperature, removing the toluene solvent under reduced pressure, and adding a heptane solvent to obtain a cocatalyst F (1M, heptane solution) with the total volume of the mixed solution being 15 mL.

And (3) product analysis: taking a certain amount of cocatalyst F (same as example 1), slowly adding excessive water to decompose the cocatalyst F, wherein the content of aluminum in the liquid-phase component is 3.4 wt% by ICP test; gas phase composition test isobutane content 94 wt%, methane content 6 wt%.

Example 7 (polymerization example)

The ethylene oligomerization reaction adopts a stainless steel polymerization kettle. The autoclave is heated to 80 ℃, vacuumized, replaced by nitrogen for a plurality of times, cooled to room temperature, and then filled with ethylene for replacement for a plurality of times. Adding heptane at 40 ℃, adding 2.5 mu mol of 2-n-butyryl-1, 10-phenanthroline condensed 2, 6-diethylaniline iron (II) chloride and 500 mu mol of cocatalyst A (calculated by aluminum) in sequence, wherein the total volume of the mixed solution is 100mL, and the molar ratio of the iron complex to the cocatalyst is 1: 200, controlling the reaction pressure to be 1MPa, and introducing ethylene to carry out ethylene oligomerization. Keeping the ethylene pressure at 1MPa and the reaction temperature at 30 ℃ for reacting for 30 minutes; (7) the reaction was stopped and a small amount of the reaction product was taken out and analyzed by Gas Chromatography (GC), and the results of the analysis are shown in Table 1.

Example 8 (polymerization example)

The same as example 7, except that the amount of the cocatalyst A (calculated as aluminum) was 250. mu. mol, and the molar ratio of the iron complex to the cocatalyst was 1: 100, the reaction results are shown in table 1.

Example 9 (polymerization example)

The same as example 7 except that the iron complex was changed to iron (II) 2-n-butyryl-1, 10-phenanthroline 2, 6-dichloroaniline chloride; the reaction results are shown in Table 1.

Example 10 (polymerization example)

The same as example 7 except that cocatalyst A was changed to cocatalyst B; the reaction results are shown in Table 1.

Example 11 (polymerization example)

The same as example 7 except that cocatalyst A was changed to cocatalyst C; the reaction results are shown in Table 1.

Example 12 (polymerization example)

The same as example 7 except that cocatalyst A was changed to cocatalyst D; the reaction results are shown in Table 1.

Example 13 (polymerization example)

The same as example 7 except that cocatalyst A was changed to cocatalyst E; the reaction results are shown in Table 1.

Example 14 (polymerization example)

The same as example 7 except that cocatalyst A was changed to cocatalyst F; the reaction results are shown in Table 1.

Example 15 (polymerization example)

The same as example 7, except that the reaction pressure was changed from 1MPa to 3 MPa; the reaction results are shown in Table 1.

Example 16 (polymerization example)

The same as example 7 except that the iron complex was changed to 2-formyl-1, 10-phenanthroline iron (II) chloride, 2, 6-diethylanilide; the reaction results are shown in Table 1.

Example 17 (polymerization example)

The same as example 7 except that the iron complex was changed to 2-acetyl-1, 10-phenanthroline iron (II) chloride, 2, 6-diethylanilide; the reaction results are shown in Table 1.

Example 18 (polymerization example)

The same as example 7 except that the iron complex was changed to 2-propionyl-1, 10-phenanthroline iron (II) chloride, 2, 6-diethylanilide; the reaction results are shown in Table 1.

Example 19 (polymerization example)

The same as example 7 except that the iron complex was changed to 2-isobutyryl-1, 10-phenanthroline iron (II) chloride, 2, 6-diethylanilide; the reaction results are shown in Table 1.

Comparative example 1 (polymerization example)

The same as example 7 except that the cocatalyst A was changed to methylaluminoxane (1.5M in toluene); the reaction results are shown in Table 1.

Comparative example 2 (polymerization example)

The same as example 7 except that the solvent heptane was changed to toluene and the cocatalyst A was changed to methylaluminoxane (1.5M toluene solution); the reaction results are shown in Table 1.

Comparative example 3 (polymerization example)

An equal amount (as in example 1) of methylaluminoxane (1.5M in toluene) was taken and the solvent was removed in vacuo to leave a white powdery solid as a residue which was not dissolved by addition of heptane. The resulting polymer was used in polymerization reaction under the same conditions as in example 7, and the reaction did not proceed normally.

Comparative example 4 (polymerization example)

The same as example 7 except that cocatalyst A was changed to modified methylaluminoxane (aluminum content 3.4% by weight, heptane solution, isobutane content 63% by weight, methane content 37% by weight). The modified methylaluminoxane is prepared by adding heptane into a 7 wt% heptane solution of commercial MMAO-3A and diluting. The reaction results are shown in Table 1.

TABLE 1

As can be seen from table 1: the cocatalyst can be completely dissolved in an alkane solvent, and has high catalytic activity in the reaction; the commercially available methylaluminoxane can only be dissolved in an aromatic hydrocarbon solvent, and when the methylaluminoxane is used for oligomerization reaction, the catalytic activity is obviously reduced no matter the methylaluminoxane solvent is an alkane solvent or an aromatic hydrocarbon solvent; the commercially available methylaluminoxane can not be effectively used for the reaction because the white powder solid obtained by removing the solvent can not be dissolved in the alkane solvent; the catalytic activity of commercially available modified methylaluminoxane is relatively low.

Any numerical value mentioned in this specification, if there is only a two unit interval between any lowest value and any highest value, includes all values from the lowest value to the highest value incremented by one unit at a time. For example, if it is stated that the amount of a component, or a value of a process variable such as temperature, pressure, time, etc., is 50 to 90, it is meant in this specification that values of 51 to 89, 52 to 88 … …, and 69 to 71, and 70 to 71, etc., are specifically enumerated. For non-integer values, units of 0.1, 0.01, 0.001, or 0.0001 may be considered as appropriate. These are only some specifically named examples. In a similar manner, all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be disclosed in this application.

It should be noted that the above-mentioned embodiments are used for explaining the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to the exemplary embodiments illustrated above, but it is understood that all words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.

Claims

1. A catalyst composition comprises a 2-acyl-1, 10-phenanthroline amine iron (II) chloride complex shown in formula I and an alkane solution containing an aluminum cocatalyst;

wherein each variable in formula (la) is defined as follows:

r' is hydrogen or C₁-C₅An alkyl group;

R¹-R⁵each independently is hydrogen, C₁-C₆Alkyl, halogen, C₁-C₆Alkoxy or nitro;

step a: reacting water with an aromatic hydrocarbon solution of aluminum alkyl; wherein, the alkyl aluminumIs of the general formula R₁R₂R₃Al，R₁、R₂And R₃Same or different, independently selected from C₁-C₂₀Alkyl groups of (a); the molar ratio of water to the aluminum alkyl in step a is (0.5-1): 1;

step b: heating and refluxing the solution obtained after the reaction in the step a and the aromatic hydrocarbon solution of the aluminoxane; alkyl groups and R in said aluminoxanes₁、R₂And R₃Different;

step c: b, reacting the solution obtained after the reaction in the step b with water, removing aromatic hydrocarbon, and adding alkane to obtain an alkane solution containing the aluminum cocatalyst; the molar ratio of water to the aluminoxane in step c is (0.1-0.3): 1.

2. The catalyst composition of claim 1, wherein the aluminum alkyl has the formula wherein R₁、R₂And R₃Same or different, independently selected from C₁-C₁₀Alkyl group of (1).

3. The catalyst composition of claim 2, wherein the aluminum alkyl has the formula wherein R₁、R₂And R₃And the same is selected from one of methyl, ethyl, n-propyl, isopropyl, butyl, isobutyl, tert-butyl and n-pentyl.

4. The catalyst composition of any of claims 1-3, wherein the aluminoxane is selected from at least one of methylaluminoxane and ethylaluminoxane.

5. The catalyst composition of any one of claims 1-3, wherein step a comprises reacting the water with an aromatic hydrocarbon solution of an aluminum alkyl at-20 ℃ to 10 ℃ for 0.1h to 1h, followed by heating under reflux for 0.1h to 1 h.

6. The catalyst composition of claim 5, wherein step a comprises reacting the water with an aromatic hydrocarbon solution of an aluminum alkyl at-10 ℃ to 0 ℃ for 0.1h to 1h, followed by heating to reflux for 0.1h to 1 h.

7. The catalyst composition of any one of claims 1 to 3, wherein the step b comprises mixing the solution obtained after the reaction in the step a with an aromatic hydrocarbon solution of aluminoxane at a temperature of 5 ℃ to 40 ℃, followed by heating and refluxing for 0.1h to 1 h.

8. The catalyst composition of claim 7, wherein the step b comprises mixing the solution obtained after the reaction of the step a with an aromatic hydrocarbon solution of aluminoxane at room temperature, and then heating and refluxing for 0.1 to 1 hour.

9. The catalyst composition of any of claims 1-3, wherein the molar ratio of the aluminoxane to the aluminum alkyl in step b is (0.1-3): 1.

10. The catalyst composition of claim 9, wherein the molar ratio of the aluminoxane to the aluminum alkyl in step b is (0.5-1): 1.

11. The catalyst composition according to any one of claims 1 to 3, wherein the step c comprises reacting the solution obtained after the reaction in the step b with water at-20 ℃ to 10 ℃ for 0.1h to 1h, and then heating under reflux for 0.1h to 1 h.

12. The catalyst composition of claim 11, wherein the step c comprises reacting the solution obtained after the reaction in the step b with water at-10 ℃ to 0 ℃ for 0.1h to 1h, and then heating and refluxing for 0.1h to 1 h.

13. The catalyst composition of any one of claims 1-3, wherein the alkane is selected from one or more of pentane, heptane, hexane, methylcyclohexane, cyclohexane, and cyclopentane;

the aromatic hydrocarbon includes a substituted or unsubstituted aromatic hydrocarbon.

14. The catalyst composition of claim 13, wherein the aromatic hydrocarbon is selected from one or more of toluene, xylene, or nitrobenzene.

15. The catalyst composition of any one of claims 1-3, wherein R is₁-R₃And when the catalyst is isobutyl, the content of isobutane in the gas-phase product is higher than 75 wt% measured by gas chromatography after the aluminum-containing cocatalyst is hydrolyzed.

16. The catalyst composition of claim 15, wherein R is₁-R₃And when the catalyst is isobutyl, the content of the isobutane in the gas-phase product is 78-94 wt% measured by gas chromatography after the aluminum-containing cocatalyst is hydrolyzed.

17. The catalyst composition of any of claims 1-3, wherein the molar ratio of aluminum in the cocatalyst to iron in the procatalyst is (30-900): 1.

18. The catalyst composition of claim 17, wherein the molar ratio of aluminum in the co-catalyst to iron in the main catalyst is (30-500): 1.

19. The catalyst composition of claim 17, wherein the molar ratio of aluminum in the co-catalyst to iron in the main catalyst is (50-300): 1.

20. A method of using a catalyst composition comprising carrying out an oligomerization of ethylene in the presence of the catalyst composition of any of claims 1-19.

21. Use according to claim 20, characterized in that the oligomerization of ethylene is carried out in an organic solvent.

22. Use according to claim 20, characterized in that the oligomerization of ethylene is carried out in an alkane.

23. The use according to any one of claims 20 to 22, wherein in the ethylene oligomerization reaction, the reaction temperature is 0 to 200 ℃; the ethylene pressure is 0.1-20.0 MPa.

24. The use method of claim 23, wherein in the ethylene oligomerization reaction, the reaction temperature is 0-100 ℃; the ethylene pressure is 0.5-5.0 MPa.