Ethylene oligomerization catalysis process

Abstract

The application provides an ethylene oligomerization catalytic process, comprising: contacting ethylene with a catalyst in a reactor, wherein the contacting conditions comprise: the temperature is 40-90 DEG C, and the catalyst comprises a main catalyst, an aluminum-containing cocatalyst, an organic solvent and water, the main catalyst is selected from one or more of compounds shown in formula (1), in formula (1), R1-R 11 are the same or different, each independently selected from hydrogen, C1-C6 alkyl, halogen, C1-C6 alkoxy and nitro; R 12 is selected from hydrogen, C1-C6 alkyl, C6-C 18 alkylaryl and C6-C 18 aralkyl; M is Fe (II), Co (II) or Ni (II). The catalytic process provided by the application can use condensed water as the heat removal medium, compared with refrigerated water, the energy consumption is reduced, and the industrial application value is obviously improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ethylene oligomerization process, in particular to an ethylene oligomerization catalysis process. BACKGROUND

[0002] Linear alpha-olefins generally refer to high-carbon straight-chain terminal olefins with carbon number of 4 or more, which are widely used in the synthesis of lubricating oil base oil, comonomer, surfactant, plasticizer, bactericide, emulsifier and other chemical products. For example, 1-butene, 1-hexene and 1-octene are mainly used as polyethylene comonomers; 1-decene is a raw material for synthesizing high-grade lubricating oil base oil; C 10 -C 14 Alpha-olefins with carbon number of 4-6 can be used to produce pour point depressants, C 14 -C 18 Alpha-olefins with carbon number of 8-14 can be used to produce alpha-olefin sulfonate AOS, which is the main component of heavy-duty low-phosphate laundry detergent; C 18 The above alpha-olefins can be directly used as lubricating oil additives and drilling fluids. In recent years, the rapid development of high-function PE, lubricants and advanced detergents has led to a sharp increase in demand for alpha-olefins.

[0003] Linear alpha-olefins were initially produced by paraffin cracking method, but the paraffin cracking method produces alpha-olefin mixtures containing odd and even carbon numbers, which also contain impurities such as internal olefins, dienes, branched olefins and aromatic hydrocarbons, and the composition is complex, the product purity is poor, and it is difficult to meet the needs of comonomers, synthetic surfactants and other products. In order to produce high-quality alpha-olefin products that meet market needs, countries such as Europe and the United States have gradually developed and developed ethylene oligomerization method, which is a carbon chain growth reaction of ethylene monomer in the presence of a catalyst to obtain alpha-olefin products containing even carbon atoms. With the development of ethylene oligomerization method, paraffin cracking method has been gradually eliminated, and by the 20th century, all paraffin cracking production devices abroad have been shut down, and ethylene oligomerization method is used to produce high-quality alpha-olefin products.

[0004] German patent DE1443927 discloses a one-step process of Gulf Company, and US patent US3906053 discloses a two-step process of Ethyl Company, but neither of them solves the problem of blockage of reaction equipment by polyethylene wax generated in the oligomerization. US patents US3676523, US3686351 and US3726938 disclose Shell Higher Olefin Process (Shell Higher Olefin Process) of Shell Company, which is SHOP process. This is currently the most successful ethylene oligomerization process recognized in the world, which uses nickel-based catalyst, has a wide product distribution, and exists a large amount of C 20and above, seriously affect the operation of the equipment. The process isomerizes and converts the digestion of this part of the product by transalkylation with low carbon olefins, resulting in a long process route and high energy consumption, which is only economically viable on a large scale. European Patent EP177999 and Japanese JP6259225 disclose a process for the preparation of linear alpha-olefins by ethylene oligomerization using metallocene catalysts, which has a relatively high reaction pressure and generates high polymers, which is also prone to pipeline blockage.

[0005] Patents US610394, US5955555, CN01105268.6, CN01109134.7 and CN101649012A disclose the use of a complex of a 2,6-pyridine carboxylic acid (bis-imine) or 2,6-diacetyl pyridine (bis-imine) ligand with iron as a catalyst for the production of linear alpha-olefins by ethylene oligomerization, which has excellent catalytic performance. US Patent US2002 / 0016521 discloses a method for manufacturing alpha-olefins using such a catalyst, in which a full-liquid continuous stirred tank reactor is used, and an arbitrary number of reactors can be connected in series as the last reactor, which can be a plug flow tubular reactor; the reaction temperature of this method is relatively low, between 35°C and 80°C, but the reaction pressure needs to be above the bubble point of ethylene to ensure that all components (including ethylene) remain in the liquid phase, so that there is only a single liquid phase in the reactor, and the product distribution range of the obtained alpha-olefins is relatively narrow, with a K value of 0.65-0.8 (K = chain growth rate / (chain growth rate + chain transfer rate) = moles of C n+2 / moles of C n In US Patent US2004 / 0111002 and Chinese Patent CN1330612C, it is disclosed that the use of such iron-based catalysts in an improved plug flow reactor has a much lower average concentration of alpha-olefins along the length of the reactor than a continuous stirred reactor, resulting in less impurities of non-linear alpha-olefins, which is beneficial for the production of purer alpha-olefins; compared with an unimproved plug flow reactor, this method can use a lower ethylene pressure, thereby reducing investment costs, but the reaction pressure in this method also needs to be maintained above the bubble point of ethylene to ensure that all components (including ethylene) remain in the liquid phase, so that there is only a single liquid phase in the reactor, and the product distribution range of the obtained alpha-olefins is relatively narrow.

[0006] It can be seen that the existing linear alpha-olefin preparation process still has quite a few problems, most of the reaction conditions are harsh, the operation process is complex, and there are high molecular weight polyethylene wax and impurities such as non-linear alpha-olefins in the reaction product, and the activity and catalytic efficiency of the catalyst are also problems that need to be concerned in the industrial production of linear alpha-olefins. Therefore, it is necessary to further study the process of preparing linear alpha-olefins by ethylene oligomerization. SUMMARY

[0007] In view of the problems existing in the prior art, the purpose of the present application is to provide an ethylene oligomerization catalytic process, which can make the oligomerization reaction proceed at a higher temperature by using a specific catalyst, the oligomerization reaction is initiated rapidly, the operation is stable, and the repeatability is good; and as the reaction temperature rises, the activity of the catalyst remains at a very high level, and as the reaction temperature gradually rises, when the reaction temperature reaches a higher temperature of 60-70℃, the product distribution coefficient can still reach about 0.7 without significant decrease, and the reaction temperature is 60-70℃, the reaction heat removal medium can use condensed water, which reduces the energy consumption compared with chilled water, and the industrial application value is obviously improved. The above experimental results overcome the technical bias of the skilled person in the art and achieve unexpected technical effects.

[0008] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0009] An ethylene oligomerization catalytic process, comprising: contacting ethylene with a catalyst in a reactor, wherein the contacting conditions include: a temperature of 40℃ to 90℃, preferably 40℃ to 80℃, and further preferably 50℃ to 70℃, and

[0010] The catalyst comprises a main catalyst, an aluminum-containing cocatalyst, an organic solvent and water, the main catalyst is selected from one or more of the compounds represented by formula (1),

[0011]

[0012] In formula (1), R1-R 11 are the same or different, each independently selected from hydrogen, C1-C6 alkyl, halogen, C1-C6 alkoxy and nitro; R 12 is selected from hydrogen, C1-C6 alkyl, C6-C 18 alkylaryl and C6-C 18 aralkyl; M is Fe(II), Co(II) or Ni(II).

[0013] In some preferred embodiments of the present application, the temperature of the contacting is preferably 45℃ to 65℃.

[0014] In some preferred embodiments of the present application, the conditions of the contacting further comprise: using condensed water as the heat removal medium of the reactor, preferably, the condensed water has a temperature of 10-35°C, preferably 20-35°C, more preferably 25-35°C.

[0015] In some preferred embodiments of the present application, the conditions of the contacting further comprise: controlling the pressure of ethylene in the reactor to be 0.1-30 MPa, preferably 0.5-10 MPa, more preferably 0.5-3 MPa.

[0016] In some preferred embodiments of the present application, the conditions of the contacting further comprise: controlling the time of the contacting to be 10-100 min, preferably 10-50 min, more preferably 20-40 min.

[0017] In some preferred embodiments of the present application, in formula (1), R1-R6 11 are the same or different, each independently selected from hydrogen, C1-C4 linear alkyl, C3-C6 branched alkyl, C3-C6 cycloalkyl, halogen, C1-C4 alkoxy and nitro; R 12 is selected from hydrogen, C1-C4 linear alkyl, C3-C6 branched alkyl, C3-C6 cycloalkyl, C6-C 12 alkylaryl and C6-C 12 aralkyl; M is Fe(II).

[0018] In some preferred embodiments of the present application, in formula (1), R1-R6 11 are the same or different, each independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, fluorine, chlorine, bromine, methoxy, ethoxy and nitro; R 12 is selected from hydrogen, C1-C4 alkyl, methylphenyl, 1,2-dimethylphenyl, 1,3-dimethylphenyl, 1,4-dimethylphenyl, benzyl and phenethyl.

[0019] In some preferred embodiments of the present application, in formula (1), R1-R6 are hydrogen, R7 and R 11 are methyl, and R8-R 10 are hydrogen.

[0020] In some preferred embodiments of the present application, the aluminum-containing cocatalyst is selected from one or more of alkylaluminum, trialkenylaluminum, dialkylaluminum halide, alkylaluminum sesquihalide, dialkylaluminum hydride, partially hydrogenated alkylaluminum, aluminoxane and dialkylaluminum alcoholate,

[0021] wherein, the general formula of the alkylaluminum is shown as formula (2),

[0022] AlR n Xm Formula (2)

[0023] In Formula (2), R is each independently a linear or branched C1-C8 alkyl group; X is a halogen, preferably chlorine or bromine; n is an integer of 1 to 3, m is an integer of 0 to 2, and m+n is equal to 3; preferably, the alkylaluminum is selected from at least one of trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, and ethylaluminum dichloride; more preferably triethylaluminum;

[0024] The trialkenylaluminum is triisoprenylaluminum;

[0025] The alkylaluminum halide is selected from diethylaluminum chloride, dibutylaluminum chloride, diisobutylaluminum chloride, and diethylaluminum bromide;

[0026] The alkylaluminum sesquihalide is selected from ethylaluminum sesquichloride, butylaluminum sesquichloride, and ethylaluminum sesquibromide;

[0027] The dialkylaluminum hydride is selected from diethylaluminum hydride and dibutylaluminum hydride;

[0028] The partially hydrogenated alkylaluminum is selected from ethylaluminum dihydride and propylaluminum dihydride;

[0029] The oxyalkane is selected from methylaluminoxane, isobutylaluminoxane, tetraethylaluminoxane, and tetraisobutylaluminoxane;

[0030] The dialkylaluminum alkoxide is diethylaluminum ethoxide.

[0031] In some preferred embodiments of the present application, the organic solvent is selected from inert organic solvents, preferably one or more selected from unsubstituted or halogen-substituted aromatic hydrocarbon solvents, aliphatic alkanes, cycloaliphatic hydrocarbon compounds, and halogenated alkanes, preferably one or more selected from toluene, benzene, xylene, chlorobenzene, dichlorobenzene, chlorotoluene, alkane, hexane, heptane, octane, nonane, decane, cyclohexane, decaline, dichloroethane, and dichlorobutane, more preferably cyclohexane.

[0032] In some preferred embodiments of the present application, the water content in the catalyst is 100 ppm to 550 ppm, preferably 210 ppm to 240 ppm, more preferably 210 ppm to 230 ppm, further preferably 220 ppm to 230 ppm, based on the total weight of the organic solvent.

[0033] In some preferred embodiments of the present application, the molar ratio of aluminum element in the aluminum-containing cocatalyst to M element in the main catalyst in the catalyst is 30:1 to less than 900:1, preferably 100:1 to 700:1, and more preferably 148:1 to 196:1.

[0034] In some preferred embodiments of the present application, the content of the main catalyst in the catalyst is 1 μmol / L to 500 μmol / L, preferably 10 μmol / L to 300 μmol / L, and more preferably 10 μmol / L to 100 μmol / L, based on the total volume of the catalyst.

[0035] According to the present application, the catalytic process provided by the present application can be applied to single-kettle process or multi-kettle series process. Those skilled in the art can select according to production needs.

[0036] The present application has at least the following advantages:

[0037] Firstly, the catalytic process provided by the present application can be carried out at a relatively high temperature range (for example, 40℃ to 90℃), and the reaction heat removal medium can be condensate water, which reduces energy consumption compared with chilled water. Thus, the technical prejudice of those skilled in the art is overcome, and unexpected technical effects are achieved.

[0038] Secondly, the catalytic process provided by the present application can have relatively high catalytic activity, and the selectivity of α-olefin can reach more than 96%.

[0039] Thirdly, the catalytic process provided by the present application can use cheap and readily available cyclohexane as a solvent, and in addition to reducing production costs, using cyclohexane as a solvent can also make the oligomerization product free of impurities. DETAILED DESCRIPTION

[0040] The present application is described in detail below through examples, but the scope of protection of the present application is not limited to the following description.

[0041] In the examples, the specific conditions not specified are carried out according to conventional conditions or manufacturer's recommended conditions. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be obtained through market channels.

[0042] In the present application, the product distribution factor (k) = ethylene oligomerization chain growth rate / (chain growth rate + chain transfer rate) = C 2n+2 / C 2n .

[0043] In the present application, Al / Fe refers to the molar ratio of aluminum element to iron element.

[0044] In the following embodiments, the cyclohexane solvent used is anhydrous cyclohexane.

[0045] Example 1

[0046] (1) The reaction kettle was replaced by high-temperature drying, vacuum replacement and other operations to ensure that the reaction kettle was free of water and oxygen;

[0047] (2) The reaction kettle was replaced with ethylene to make the reaction system in an ethylene environment;

[0048] (3) Water and cyclohexane solvent were added to the reaction kettle, 1.37 mL of triethylaluminum cyclohexane solution (the concentration of triethylaluminum was 715 μmol / mL) was added, and 2 mL of chloro-2-formyl-1,10-phenanthroline-2,6-dimethylanilino iron (II) complex cyclohexane solution (the concentration of chloro-2-formyl-1,10-phenanthroline-2,6-dimethylanilino iron (II) complex was 2.5 μmol / mL) was added, making the total amount of the composition 100 mL, wherein the weight content of water was 225 ppm based on the weight of cyclohexane, Al / Fe (molar ratio) = 196, and after sufficient stirring, ethylene was introduced to start the oligomerization reaction;

[0049] (4) The reaction was carried out at an ethylene pressure of 1 MPa and a reaction temperature of 60°C for 30 minutes;

[0050] (5) The reaction was stopped, and a small amount of reaction product was taken out for gas chromatography (GC) analysis, and the specific analysis results are shown in Table 1.

[0051] Example 2

[0052] (1) The reaction system was replaced by high-temperature drying, vacuum replacement and other operations to ensure that the reaction kettle was free of water and oxygen;

[0053] (2) The reaction system was replaced with ethylene to make the reaction system in an ethylene environment;

[0054] (3) Water and anhydrous cyclohexane solvent were added to the reaction kettle, 1.37 mL of triethylaluminum cyclohexane solution (the concentration of triethylaluminum was 715 μmol / mL) was added, and 2 mL of chloro-2-benzoyl-1,10-phenanthroline-2,6-dimethylanilino iron (II) complex cyclohexane solution (the concentration of chloro-2-benzoyl-1,10-phenanthroline-2,6-dimethylanilino iron (II) complex was 2.5 μmol / mL) was added, making the total amount of the cyclohexane solution 100 mL, wherein the weight content of water was 225 ppm based on the weight of cyclohexane, Al / Fe = 196, and after sufficient stirring, ethylene was introduced to start the oligomerization reaction;

[0055] (4) maintain the ethylene pressure at 1 MPa and the reaction temperature at 50°C for 30 minutes;

[0056] (5) stop the reaction, take out a small amount of the reaction product and analyze it by gas chromatography (GC): the oligomerization activity is 3.06 x 10 7 g-mol(Fe) -1 h -1 The C4 content is 14.24%, of which 98.7% is linear α-olefin. The remaining mixture is neutralized with a 5% hydrochloric acid-acidified ethanol solution, and no polymer is obtained. The K value is 0.66.

[0057] The specific analysis results are shown in Table 1.

[0058] Example 3

[0059] (1) The reaction system is replaced by high-temperature drying, vacuum replacement, etc. to ensure that there is no water and oxygen in the reaction kettle;

[0060] (2) The reaction system is replaced with ethylene to make the reaction system in an ethylene environment;

[0061] (3) Add water and cyclohexane solvent to the reaction kettle, add 1.37 mL of triethylaluminum cyclohexane solution (the concentration of triethylaluminum is 715 μmol / mL), and add 2 mL of chloro-2-propionyl-1,10-phenanthroline-2,6-dimethyl aniline iron (II) complex cyclohexane solution (the concentration of chloro-2-propionyl-1,10-phenanthroline-2,6-dimethyl aniline iron (II) complex is 2.5 μmol / mL), and make the total amount of the composition 100 mL, wherein the weight content of water is 225 ppm based on the weight of cyclohexane, Al / Fe = 196, and after sufficient stirring, ethylene is introduced to start the oligomerization reaction;

[0062] (4) maintain the ethylene pressure at 1 MPa and the reaction temperature at 50°C for 30 minutes;

[0063] (5) stop the reaction, take out a small amount of the reaction product and analyze it by gas chromatography (GC): the oligomerization activity is 3.06 x 10 7 g-mol(Fe) -1 h -1 The C4 content is 14.24%, of which 98.7% is linear α-olefin. The remaining mixture is neutralized with a 5% hydrochloric acid-acidified ethanol solution, and no polymer is obtained. The K value is 0.66.

[0064] The specific analysis results are shown in Table 1.

[0065] Example 4

[0066] (1) The reaction system was replaced by high temperature drying, vacuum replacement, etc. to ensure that there was no water and no oxygen in the reaction kettle;

[0067] (2) The reaction system was replaced by ethylene to make the reaction kettle in an ethylene environment;

[0068] (3) Water and anhydrous cyclohexane solvent were added to the reaction kettle, 1.37 mL of triethylaluminum cyclohexane solution (the concentration of triethylaluminum was 715 μmol / mL), 2 mL of chloro-2-butyryl-1,10-phenanthroline-2,6-dimethyl aniline iron (II) complex cyclohexane solution (the concentration of chloro-2-butyryl-1,10-phenanthroline-2,6-dimethyl aniline iron (II) complex was 2.5 μmol / mL), and the total amount of the composition was 100 mL, wherein the weight content of water was 225 ppm based on the weight of cyclohexane, Al / Fe = 196, after sufficient stirring, ethylene was introduced to start the oligomerization reaction;

[0069] (4) The reaction was carried out at an ethylene pressure of 1 MPa and a reaction temperature of 50°C for 30 minutes;

[0070] (5) The reaction was stopped, and a small amount of reaction product was taken out for gas chromatography (GC) analysis: the oligomerization activity was 3.12 x 10 7 g·mol(Fe) -1 ·h -1 , the C4 content was 13.40%, of which linear α-olefin was 98.6%. The remaining mixture was neutralized with 5% hydrochloric acid acidified ethanol solution, and no polymer was obtained. The K value was 0.67.

[0071] The specific analysis results are shown in Table 1.

[0072] Example 5

[0073] (1) The reaction kettle was replaced by high temperature drying, vacuum replacement, etc. to ensure that there was no water and no oxygen in the reaction kettle;

[0074] (2) The reaction kettle was replaced by ethylene to make the reaction system in an ethylene environment;

[0075] (3) In a reaction vessel, water and cyclohexane solvent were added, 1.37 mL of triethylaluminum cyclohexane solution (the concentration of triethylaluminum was 715 μmol / mL) was added, 2 mL of chloro-2-isobutyryl-l,10-phenanthroline-2,6-dimethylanilino iron (II) complex cyclohexane solution (the concentration of chloro-2-isobutyryl-l,10-phenanthroline-2,6-dimethylanilino iron (II) complex was 2.5 μmol / mL) was added, and the total amount of the composition was made to be 100 mL, wherein the weight content of water was 225 ppm based on the weight of cyclohexane, Al / Fe = 196, and after sufficient stirring, ethylene was introduced to start the oligomerization reaction;

[0076] (4) The reaction was continued for 30 minutes at 1 MPa of ethylene pressure and 50°C of reaction temperature;

[0077] (5) The reaction was stopped, and a small amount of the reaction product was taken out and subjected to gas chromatography (GC) analysis. The detailed analysis results are shown in Table 1.

[0078] Example 6

[0079] "Chloro-2-formyl-l,10-phenanthroline-2,6-diethylanilino iron (II) complex" was used instead of "chloro-2-formyl-l,10-phenanthroline-2,6-dimethylanilino iron (II) complex" in Example 1.

[0080] After the reaction was stopped, a small amount of the reaction product was taken out and subjected to gas chromatography (GC) analysis. The detailed analysis results are shown in Table 1.

[0081] Example 7

[0082] "Toluene" was used instead of "cyclohexane" in Example 1.

[0083] After the reaction was stopped, a small amount of the reaction product was taken out and subjected to gas chromatography (GC) analysis. The detailed analysis results are shown in Table 1.

[0084] Example 8

[0085] "Methylaluminoxane" was used instead of "triethylaluminum" in Example 1.

[0086] After the reaction was stopped, a small amount of the reaction product was taken out and subjected to gas chromatography (GC) analysis. The detailed analysis results are shown in Table 1.

[0087] Comparative Example 1

[0088] The only difference from Example 1 was that the reaction temperature was 10°C.

[0089] After the reaction was stopped, a small amount of the reaction product was taken out and subjected to gas chromatography (GC) analysis. The detailed analysis results are shown in Table 1.

[0090] Comparative Example 2

[0091] The only difference from Example 1 is that the reaction temperature is 30°C.

[0092] After the reaction was stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0093] Table 1

[0094]

[0095]

[0096] Note: In the table above, k refers to the product distribution coefficient.

[0097] As can be seen from the data in the table above, the ethylene oligomerization process provided by this invention can reduce undesirable C4 olefins and C4 olefins. 20 ~C 28 The olefin content increases the desired C6-C6 content. 18 Especially C6 to C 18 The content of linear α-olefins. Furthermore, the ethylene oligomerization process of this invention can be carried out at relatively high temperatures, which allows condensate to be used as the heat dissipation medium in industrial applications instead of cooling water.

[0098] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. An ethylene oligomerization catalysis process comprising: ethylene is contacted with a catalyst in a reactor, wherein the conditions of the contacting include a temperature of 50°C to 70°C, and the catalyst includes a procatalyst, an aluminum-containing cocatalyst, an organic solvent, and water, the procatalyst is selected from one or more of the compounds represented by formula (1), Formula (1) In formula (1), R1to R6are hydrogen, R7and R 11 are methyl, and R8to R 10 are hydrogen. R 12 selected from C3-C6 branched alkyl; M is Fe(II); the aluminum-containing cocatalyst is selected from one or more of an alkylaluminum, an alkylaluminum halide, and an aluminoxane; the organic solvent is selected from one or more of an aromatic hydrocarbon solvent that is unsubstituted or substituted with halogen, an aliphatic alkane, an alicyclic hydrocarbon compound, and a halogenated alkane.

2. Catalytic process according to claim 1, characterized in that, the conditions of the contacting further include using condensed water as a heat removal medium for the reactor, the condensed water having a temperature of 10°C to 35°C.

3. Catalytic process according to claim 2, characterized in that, the condensed water has a temperature of 25°C to 35°C.

4. The catalytic process of claim 1, wherein, the conditions of the contacting further include controlling a pressure of ethylene in the reactor to be 0.1 MPa to 30 MPa.

5. Catalytic process according to claim 4, characterized in that, the pressure of ethylene in the reactor is controlled to be 0.5 MPa to 3 MPa.

6. The catalytic process of claim 1, wherein, the conditions of the contacting further include controlling a time of the contacting to be 10 min to 100 min.

7. Catalytic process according to claim 6, characterized in that, the time of the contacting is controlled to be 20 min to 40 min.

8. The catalytic process according to any one of claims 1 to 7, wherein the alkylaluminum is represented by formula (2), AlR n X m Formula (2) in formula (2), R is each independently a linear or branched C1-C8 alkyl group; X is halogen; n is an integer of 1 to 3, and m is an integer of 0 to 2, and m+n is equal to 3; the alkylaluminum halide is selected from ethylaluminum sesquichloride, butylaluminum sesquichloride, and ethylaluminum sesquibromide; the aluminoxane is selected from methylaluminoxane, isobutylaluminoxane, tetraethylaluminoxane, and tetraisobutylaluminoxane.

9. Catalytic process according to claim 8, characterized in that, in formula (2), X is chlorine or bromine; the alkylaluminum is selected from at least one of trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, and ethylaluminum dichloride.

10. The catalytic process of claim 9, wherein, the alkylaluminum is triethylaluminum.

11. Catalytic process according to any one of claims 1-7, characterized in that, the organic solvent is selected from one or more of toluene, benzene, xylene, chlorobenzene, dichlorobenzene, chlorotoluene, pentane, hexane, heptane, octane, nonane, decane, cyclohexane, decaline, dichloroethane, and dichlorobutane.

12. The catalytic process of claim 11, wherein, the organic solvent is cyclohexane.

13. Catalytic process according to any one of claims 1-7, characterized in that, in the catalyst, a content of the water is 100 ppm to 550 ppm by weight based on a total weight of the organic solvent.

14. The catalytic process of claim 13, wherein, the content of the water is 210 ppm to 240 ppm by weight based on the total weight of the organic solvent.

15. The catalytic process of claim 13, wherein, the content of the water is 220 ppm to 230 ppm by weight based on the total weight of the organic solvent.

16. Catalytic process according to any one of claims 1-7, characterized in that, in the catalyst, a molar ratio of aluminum in the aluminum-containing cocatalyst to M in the procatalyst is 30:1 to less than 900:

1.

17. The catalytic process of claim 16, wherein, the molar ratio of aluminum in the aluminum-containing cocatalyst to M in the procatalyst is 100:1 to 700:

1.

18. The catalytic process of claim 16, wherein, the molar ratio of aluminum in the aluminum-containing cocatalyst to M in the procatalyst is 148:1 to 196:

1.

19. Catalytic process according to any one of claims 1-7, characterized in that, The content of the main catalyst in the catalyst is 1 μmol / L to 500 μmol / L, based on the total volume of the catalyst.

20. The catalytic process of claim 19, wherein, The content of the main catalyst in the catalyst is 10 μmol / L to 300 μmol / L, based on the total volume of the catalyst.

21. The catalytic process of claim 19, wherein, The content of the main catalyst in the catalyst is 10 μmol / L to 100 μmol / L, based on the total volume of the catalyst.

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