Catalyst System for Ethylene Oligomerization, Its Preparation Method and Application

Abstract

The present invention provides a catalyst system for ethylene oligomerization, its preparation method and application. The catalyst system includes: a chloro-2-C1-C6 acyl-1,10-phenanthroline-condensed-2,6-dimethylaniline iron(II) complex shown in formula (1), an aluminum-containing cocatalyst, water and cyclohexane; in formula (1), R is selected from C1-C6 alkyl groups; R1-R6 are the same or different and are each independently selected from hydrogen, C1-C6 alkyl groups, halogens, C1-C6 alkoxy groups and nitro groups. Under the action of this catalyst system for ethylene oligomerization, due to the action of the promoter water, the oligomerization reaction is initiated rapidly, operates stably, has good repeatability, and the reaction temperature can be 60-80 °C. The heat removal medium for the reaction can use condensed water, which reduces energy consumption compared with chilled water. Thus, it overcomes the technical prejudice of those skilled in the art and achieves unexpected technical effects.

Description

Technical Field

[0001] The present invention relates to the field of catalysts for ethylene oligomerization, and particularly to a catalyst system for ethylene oligomerization, a preparation method thereof, and an application thereof. Background Art

[0002] Linear alpha-olefin (LAO) is an olefin or alkene having a terminal double bond at the primary or alpha position. The position of the double bond determines the chemical properties and can undergo all reactions of olefins, including addition, metathesis, polymerization, etc.

[0003] Very versatile linear alpha-olefins are used as precursors for detergents, synthetic lubricants, plasticizers, surfactants, and polyolefins. Linear alpha-olefins are used as comonomers in the production of polyethylene.

[0004] The preparation of linear alpha-olefins is mainly based on the oligomerization of ethylene. The ethylene oligomerization process produces a mixture of olefins with an even carbon number of chain lengths of 4, 6, 8, etc. having a terminal double bond. It is highly desirable to have a terminal double bond, but the formation of internal olefins cannot be excluded. In addition, there is a certain amount of polymer. The key factors in ethylene oligomerization are to obtain the desired selectivity, purity of alpha-olefins, and product distribution. Therefore, the catalyst system and process conditions play an important role. Various types of catalyst systems for producing linear alpha-olefins are well known in the art.

[0005] Exxon's US4,361,714 describes a catalyst system comprising zirconium halide, as well as dialkyl zinc and organoaluminum compounds. The oligomerization is carried out in a medium of a hydrocarbon solvent at a temperature of about 50 °C to about 200 °C and at an ethylene pressure of 3.5 MPa to 10.5 MPa. However, the main disadvantages of this catalyst are its poor solubility in hydrocarbon solvents and the large production of wax and high molecular weight polyethylene as by-products, which leads to serious reactor blockage.

[0006] Idemitsu's US4,783,573 describes the synthesis of linear alpha-olefins with long chain lengths in the presence of a catalyst system based on a zirconium complex, which uses anhydrous zirconium tetrachloride, aluminum sesquichloride, and triethylaluminum in dry benzene solvent. An organic compound containing a heteroatom (such as alkyl disulfide, thioether, thiophene, and primary amine) is used as a moderator, and the oligomerization is carried out at 120 °C and at a pressure of 3.5 MPa. The main disadvantages of this method are the poor solubility of zirconium tetrachloride in hydrocarbon solvents, high reaction temperature, and relatively low selectivity for light alpha-olefins.

[0007] In CN1850339A of the Sun Wenhua research group, attempts were made on inexpensive cocatalysts. When iron(II) chloride-2-acetyl-1,10-phenanthroline-2,6-diethylaniline complex was used as the main catalyst and triethylaluminum was used as the cocatalyst, the catalytic activity was only 2.7×105 g·mol(Fe) -1 ·h -1 , which could not meet the industrial requirements; at the same time, for reaction temperatures below 40°C, chilled water was generally required as the reaction condensation medium, and a refrigeration unit was needed for refrigeration, increasing the process energy consumption. SUMMARY OF THE INVENTION

[0008] To solve the technical problems in the above-mentioned prior art that the ethylene oligomerization reaction temperature is relatively low and it is difficult to reach the required reaction temperature in practical applications, the inventors of the present application specifically proposed the present invention.

[0009] The first aspect of the present invention provides a catalyst system for ethylene oligomerization, comprising: iron(II) chloride-2-C1-C6 acyl-1,10-phenanthroline-2,6-dimethylaniline complex shown in formula (1), an aluminum-containing cocatalyst, water and cyclohexane;

[0010]

[0011] In formula (1), R is selected from C1-C6 alkyl groups; R1-R6 are the same or different and are each independently selected from hydrogen, C1-C6 alkyl groups, halogens, C1-C6 alkoxy groups and nitro groups.

[0012] The inventors of the present application found in their research that the combined use of the above components enables the ethylene oligomerization reaction participated by the formed catalyst to be carried out at a relatively high temperature, for example, 50°C to 90°C. Thus, since the reaction temperature is relatively high, it is not necessary to use chilled water, and only condensed water can be used as the cooling medium, reducing the energy consumption. In addition, for the catalyst provided by the present invention, cyclohexane can be used as the solvent. Thus, on the one hand, the cost is reduced, and on the other hand, it can avoid the solvent remaining in the product. Moreover, the ethylene oligomerization reaction participated by the catalyst system provided by the present invention is initiated rapidly, operates stably and has good repeatability.

[0013] In some preferred embodiments of the present invention, in the catalyst composition, based on the total weight of the cyclohexane as the calculation basis, the weight content of the water is 200 ppm to 250 ppm, preferably 210 ppm to 240 ppm, more preferably 210 ppm to 230 ppm, and further preferably 220 ppm to 230 ppm.

[0014] In some preferred embodiments of the present invention, the aluminum-containing cocatalyst is selected from alkylaluminum compounds. Preferably, the aluminum-containing cocatalyst is selected from at least one of the alkylaluminum compounds represented by the general formula (2).

[0015] AlR 7n X m Formula (2)

[0016] In formula (2), each R7 is independently a straight-chain or branched C1-C8 alkyl group; X is a halogen, preferably chlorine or bromine; n is an integer from 1 to 3, m is an integer from 0 to 2, and m + n equals 3; More preferably, the alkylaluminum compound is selected from at least one of trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, and ethylaluminum dichloride; Further preferably triethylaluminum.

[0017] In some preferred embodiments of the present invention, in formula (1), R is selected from C1-C4 straight-chain alkyl groups, C3-C5 branched-chain alkyl groups, and C3-C5 cycloalkyl groups, preferably selected from methyl, ethyl, propyl, 1-methylethyl, n-butyl, isobutyl, secondary butyl, and tertiary butyl, more preferably selected from methyl, ethyl, propyl, and 1-methylethyl.

[0018] In some preferred embodiments of the present invention, in formula (1), R1-R6 are the same or different and are each independently selected from hydrogen, C1-C4 alkyl groups, halogens, C1-C4 alkoxy groups, and nitro groups, preferably selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, fluorine, chlorine, bromine, methoxy, ethoxy, and nitro groups.

[0019] In some specific embodiments of the present invention, the iron(II) complex of chloro-2-C1-C6 acyl-1,10-phenanthroline condensed with 2,6-dimethylaniline represented by formula (1) is selected from at least one of the compounds having the structures represented by the following formulas.

[0020]

[0021]

[0022] In formulas (1-1) to (1-3), M represents iron(II), and R1-R6 have the same definitions as in the above embodiments.

[0023] According to the present invention, the amount of the substituted iron(II) complex of 2-C1-C6 acyl-1,10-phenanthroline condensed with 2,6-dimethylaniline represented by formula (1) can be selected according to actual production needs, such as specific scenarios such as production scale and production equipment.

[0024] In some preferred embodiments of the present invention, in the catalyst system, based on the total volume of the cyclohexane, the content of the substituted -2-C1-C6 acyl-1,10-phenanthroline condensed-2,6-dimethylaniline iron(II) complex shown in formula (1) 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.

[0025] According to the present invention, the molar ratio of aluminum in the aluminum-containing cocatalyst to iron(II) in the chlorinated -2-C1-C6 acyl-1,10-phenanthroline condensed-2,6-dimethylaniline iron(II) complex shown in formula (1) can be selected according to actual production needs, such as specific scenarios like production scale and production equipment.

[0026] In some preferred embodiments of the present invention, in the catalyst system, the molar ratio of aluminum in the aluminum-containing cocatalyst to iron(II) in the chlorinated -2-C1-C6 acyl-1,10-phenanthroline condensed-2,6-dimethylaniline iron(II) complex shown in formula (1) is 30:1 to less than 900:1, preferably 100:1 to 700:1, and more preferably 148:1 to 196:1.

[0027] According to the present invention, the chlorinated -2-C1-C6 acyl-1,10-phenanthroline condensed-2,6-dimethylaniline iron(II) complex shown in formula (1) can be prepared by known techniques, such as the preparation method reported in Chinese Patent Application CN102558242A.

[0028] The second aspect of the present invention provides a preparation method of the catalyst system according to any one of the above embodiments, including: contacting the chlorinated -2-C1-C6 acyl-1,10-phenanthroline condensed-2,6-dimethylaniline iron(II) complex shown in formula (1), the aluminum-containing cocatalyst, the water, and the cyclohexane to obtain the catalyst system.

[0029] According to the present invention, the preparation method of the catalyst system is not limited. It can be mixing all the required components, or mixing two by two or in groups of two or three and then mixing the mixtures. Additionally, the order of mixing each component is not limited.

[0030] The third aspect of the present invention provides an application of the catalyst system according to any one of the above embodiments in the ethylene oligomerization reaction.

[0031] In some preferred embodiments of the present invention, a raw material stream containing ethylene is contacted with the catalyst system.

[0032] Using the catalyst system of the present invention for ethylene oligomerization, the obtained ethylene oligomerization products include C4, C6, C8, C 10 , C 12 , C 14 , C 16 , C 18 , C 20 , C 22 and other olefins; the selectivity of α-olefins can reach more than 96%. After the ethylene oligomerization reaction is completed, GC analysis is carried out. The results show that the oligomerization activity can reach 4×10 7 g·mol(Fe) -1 ·h -1 . In addition, the remaining reaction mixture is neutralized with an ethanol solution acidified with 5% dilute hydrochloric acid, and no polymer is obtained.

[0033] According to the catalyst system provided by the present invention, when ethylene is oligomerized under the action of this catalyst system, due to the action of the promoter water, the oligomerization reaction is initiated rapidly, operates smoothly, has good repeatability, and the reaction temperature can be 60-80 °C. The reaction heat removal medium can use condensed water, which reduces the energy consumption compared with chilled water. Thus, it overcomes the technical prejudice of those skilled in the art and achieves unexpected technical effects. Detailed implementation mode

[0034] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited to the following description.

[0035] For those not specified in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial channels.

[0036] In the present invention, the product distribution coefficient (k) = ethylene oligomerization chain growth rate / (chain growth rate + chain transfer rate) = C 2n+2 / C 2n .

[0037] In the present invention, both Al / Fe refer to the molar ratio of aluminum element to iron element.

[0038] In the following embodiments, the cyclohexane solvent used is anhydrous cyclohexane.

[0039] Example 1-1

[0040] (1) The reaction system is replaced through operations such as high-temperature drying and vacuum replacement to ensure that there is no water and no oxygen in the reaction kettle;

[0041] (2) The reaction system is replaced with ethylene to make the reaction system in an ethylene environment;

[0042] (3) Add water and cyclohexane solvent into the reaction kettle. Add 1.37 mL of triethylaluminum cyclohexane solution (the concentration of triethylaluminum is 715 μmol / mL), and then add 2 mL of cyclohexane solution of iron(II) complex of 2-propionyl-1,10-phenanthroline condensed with 2,6-dimethylaniline chloride (the concentration of the iron(II) complex of 2-propionyl-1,10-phenanthroline condensed with 2,6-dimethylaniline chloride is 2.5 μmol / mL). After that, make the total amount of the composition 100 mL. Among them, based on the weight of cyclohexane, the weight content of water is 225 ppm, and Al / Fe = 196. After fully stirring, introduce ethylene to start the oligomerization reaction;

[0043] (4) Keep the ethylene pressure at 1 MPa and react at 50 °C for 30 minutes;

[0044] (5) Stop the reaction, take out a small amount of the reaction product and analyze it by gas chromatography (GC): the oligomerization activity is 3.06×10 7 g·mol(Fe) -1 ·h -1 , the C4 content is 14.24%, among which the content of linear α-olefin is 98.7%. The remaining mixture is neutralized with an ethanol solution acidified with 5% hydrochloric acid, and no polymer is obtained. The K value is 0.66.

[0045] The specific analysis results are shown in Table 1.

[0046] Example 1-2

[0047] The difference from Example 1-1 is only that "based on the weight of cyclohexane, the weight content of water is 100 ppm".

[0048] After the reaction stops, take out a small amount of the reaction product and analyze it by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0049] Example 1-3

[0050] The difference from Example 1-1 is only that "based on the weight of cyclohexane, the weight content of water is 150 ppm".

[0051] After the reaction stops, take out a small amount of the reaction product and analyze it by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0052] Example 1-4

[0053] The difference from Example 1-1 is only that "based on the weight of cyclohexane, the weight content of water is 300 ppm".

[0054] After the reaction 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.

[0055] Examples 1-5

[0056] It is different from Example 1-1 only in that "based on the weight of cyclohexane, the weight content of water is 500 ppm".

[0057] After the reaction 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.

[0058] Examples 1-6

[0059] It is different from Example 1-1 only in that "chloro-2-propionyl-1,10-phenanthroline-2,6-diethylaniline iron(II) complex" is used to replace "chloro-2-propionyl-1,10-phenanthroline-2,6-dimethylaniline iron(II) complex" in Example 1.

[0060] After the reaction 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.

[0061] Examples 1-7

[0062] It is different from Example 1-1 only in that "the reaction temperature is 10 °C".

[0063] After the reaction 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.

[0064] Examples 1-8

[0065] It is different from Example 1-1 only in that "the reaction temperature is 30 °C".

[0066] After the reaction 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.

[0067] Examples 1-9

[0068] It is different from Example 1 only in that "the reaction temperature is 40 °C".

[0069] After the reaction 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.

[0070] Examples 1-10

[0071] It is different from Example 1-1 only in that "the reaction temperature is 45 °C".

[0072] After the reaction 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.

[0073] Examples 1-11

[0074] It is only different from Example 1-1 in that "the reaction temperature is 55 °C".

[0075] After the reaction 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.

[0076] Examples 1-12

[0077] It is only different from Example 1-1 in that "the reaction temperature is 60 °C".

[0078] After the reaction 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.

[0079] Examples 1-13

[0080] It is only different from Example 1-1 in that "the reaction temperature is 70 °C".

[0081] After the reaction 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.

[0082] Examples 1-14

[0083] It is only different from Example 1-1 in that "the reaction temperature is 80 °C".

[0084] After the reaction 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.

[0085] Comparative Example 1-1

[0086] "Toluene" was used to replace "cyclohexane" in Example 1-1.

[0087] After the reaction 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.

[0088] Comparative Example 1-2

[0089] "Xylene" was used to replace "cyclohexane" in Example 1-1.

[0090] After the reaction 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.

[0091] Comparative Example 1-3

[0092] Replace "cyclohexane" in Example 1-1 with "ethanol".

[0093] After the reaction 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.

[0094] Comparative Example 1-4

[0095] Replace "cyclohexane" in Example 1-1 with "methylcyclohexane".

[0096] After the reaction 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.

[0097] Comparative Example 1-5

[0098] Replace "triethylaluminum" in Example 1-1 with "methylaluminoxane".

[0099] After the reaction 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.

[0100] Comparative Example 1-6

[0101] Replace "triethylaluminum" in Example 1-1 with "methylaluminoxane" and adjust Al / Fe to 1000.

[0102] After the reaction 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.

[0103] Table 1

[0104]

[0105]

[0106] Note: In the above table, k refers to the product distribution coefficient.

[0107] As can be seen from the data in Table 1 above,

[0108] First, the catalyst composition provided by the present invention has very high oligomerization reaction activity. When ethylene oligomerization reaction is carried out in the presence of the catalyst composition provided by the present invention, the oligomerization reaction can be rapidly initiated;

[0109] Second, the content of unwanted C4 impurities in the oligomerization product is less, and the product distribution coefficient is higher, indicating that the reaction system initiated by the catalyst composition provided by the present invention operates stably and has good repeatability;

[0110] Thirdly, the catalyst composition provided by the present invention can carry out the reaction at a relatively high reaction temperature, which is easier to achieve than the reaction temperature of 30°C to 40°C commonly used in the art. As a result, condensed water can be used as the reaction heat removal medium, reducing the energy consumption compared with the chilled water required as the reaction heat removal medium when the reaction temperature is 30°C to 40°C, and significantly enhancing the industrial application value.

[0111] Fourthly, as the reaction temperature increases, the catalyst composition provided by the present invention still maintains a very high activity. And at a relatively high temperature of 60°C to 70°C, the product distribution coefficient can still reach about 0.7 without significant decrease.

[0112] Example 2-1

[0113] (1) The reaction system was replaced through operations such as high-temperature drying and vacuum replacement to ensure that there was no water and no oxygen in the reaction kettle.

[0114] (2) The reaction system was replaced with ethylene to make the reaction kettle in an ethylene environment.

[0115] (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 cyclohexane solution of 2-butyryl-1,10-phenanthroline-2,6-dimethylaniline iron(II) chloride complex (the concentration of 2-butyryl-1,10-phenanthroline-2,6-dimethylaniline iron(II) chloride complex was 2.5 μmol / mL) was added. Then the total amount of the composition was 100 mL. Among them, based on the weight of cyclohexane as the calculation basis, the weight content of water was 225 ppm, Al / Fe = 196. After sufficient stirring, ethylene was introduced to start the oligomerization reaction.

[0116] (4) The reaction was carried out at an ethylene pressure of 1 MPa and a reaction temperature of 50°C for 30 minutes.

[0117] (5) The reaction was stopped, and a small amount of the reaction product was taken out for gas chromatography (GC) analysis: the oligomerization activity was 3.12×10 7 g·mol(Fe) -1 ·h -1 , the C4 content was 13.40%, among which the content of linear α-olefins was 98.6%. The remaining mixture was neutralized with an ethanol solution acidified with 5% hydrochloric acid, and no polymer was obtained. The K value was 0.67.

[0118] The specific analysis results are shown in Table 2.

[0119] Example 2-2

[0120] The difference from Example 2-1 is only that "based on the weight of cyclohexane, the weight content of water is 100 ppm".

[0121] After the reaction 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 2.

[0122] Example 2-3

[0123] The difference from Example 2-1 is only that "based on the weight of cyclohexane, the weight content of water is 150 ppm".

[0124] After the reaction 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 2.

[0125] Example 2-4

[0126] The difference from Example 2-1 is only that "based on the weight of cyclohexane, the weight content of water is 300 ppm".

[0127] After the reaction 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 2.

[0128] Example 2-5

[0129] The difference from Example 2-1 is only that "based on the weight of cyclohexane, the weight content of water is 500 ppm".

[0130] After the reaction 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 2.

[0131] Example 2-6

[0132] The difference from Example 2-1 is only that "chloro-2-butyryl-1,10-phenanthroline-2,6-diethylaniline iron(II) complex" is used to replace "chloro-2-butyryl-1,10-phenanthroline-2,6-dimethylaniline iron(II) complex" in Example 1.

[0133] After the reaction 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 2.

[0134] Example 2-7

[0135] The difference from Example 2-1 is only that "the reaction temperature is 10 °C".

[0136] After the reaction 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 2.

[0137] Examples 2-8

[0138] It is only different from Example 2-1 in that "the reaction temperature is 30 °C".

[0139] After the reaction 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 2.

[0140] Examples 2-9

[0141] It is only different from Example 2-1 in that "the reaction temperature is 40 °C".

[0142] After the reaction 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 2.

[0143] Examples 2-10

[0144] It is only different from Example 2-1 in that "the reaction temperature is 45 °C".

[0145] After the reaction 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 2.

[0146] Examples 2-11

[0147] It is only different from Example 2-1 in that "the reaction temperature is 55 °C".

[0148] After the reaction 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 2.

[0149] Examples 2-12

[0150] It is only different from Example 2-1 in that "the reaction temperature is 60 °C".

[0151] After the reaction 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 2.

[0152] Examples 2-13

[0153] It is only different from Example 2-1 in that "the reaction temperature is 70 °C".

[0154] After the reaction 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 2.

[0155] Examples 2-14

[0156] It is only different from Example 2-1 in that "the reaction temperature is 80 °C".

[0157] After the reaction 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 2.

[0158] Comparative Example 2-1

[0159] "Toluene" was used to replace "cyclohexane" in Example 2-1.

[0160] After the reaction 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 2.

[0161] Comparative Example 2-2

[0162] "Xylene" was used to replace "cyclohexane" in Example 2-1.

[0163] After the reaction 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 2.

[0164] Comparative Example 2-3

[0165] "Ethanol" was used to replace "cyclohexane" in Example 2-1.

[0166] After the reaction 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 2.

[0167] Comparative Example 2-4

[0168] "Methylcyclohexane" was used to replace "cyclohexane" in Example 2-1.

[0169] After the reaction 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 2.

[0170] Comparative Example 2-5

[0171] "Methylaluminoxane" was used to replace "triethylaluminum" in Example 2-1.

[0172] After the reaction 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 2.

[0173] Comparative Example 2-6

[0174] "Methylaluminoxane" was used to replace "triethylaluminum" in Example 2-1, and the Al / Fe was adjusted to 1000.

[0175] After the reaction 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 2.

[0176] Table 2

[0177]

[0178]

[0179] Note: In the above table, k refers to the product distribution coefficient.

[0180] From the data in Table 2 above, we can see that

[0181] First, the catalyst composition provided by the present invention has a high oligomerization activity. When ethylene is subjected to an ethylene oligomerization reaction in the presence of the catalyst composition provided by the present invention, the oligomerization reaction can be initiated rapidly.

[0182] Secondly, the content of undesirable C4 impurities in the oligomerization product is low, and the product distribution coefficient is high, indicating that the reaction system initiated by the catalyst composition provided by the present invention runs smoothly and has good repeatability;

[0183] Thirdly, the catalyst composition provided by the present invention can react at a higher reaction temperature, which is easier to achieve than the reaction temperature of 30°C to 40°C commonly used in the art, and thus condensed water can be used as a reaction heat removal medium, which reduces energy consumption compared to the use of chilled water as a reaction heat removal medium at a reaction temperature of 30°C to 40°C, and significantly improves the industrial application value;

[0184] Fourthly, as the reaction temperature increases, the catalyst composition provided by the present invention still maintains a high activity, and at a relatively high temperature of 60°C to 70°C, the product distribution coefficient can still reach about 0.7 without a significant decrease.

[0185] Example 3-1

[0186] (1) The reactor is replaced by high-temperature drying, vacuum replacement and other operations to ensure that there is no water and oxygen in the reactor;

[0187] (2) replacing the reactor with ethylene to place the reaction system in an ethylene environment;

[0188] (3) Add water and cyclohexane solvent to a reaction kettle, add 1.37 mL of triethylaluminum cyclohexane solution (the concentration of triethylaluminum is 715 μmol / mL), add 2 mL of 2-isobutyryl-1,10-phenanthroline-2,6-dimethylaniline iron (II) chloride solution (the concentration of 2-isobutyryl-1,10-phenanthroline-2,6-dimethylaniline iron (II) chloride complex is 2.5 μmol / mL), and make the total amount of the composition 100 mL, wherein the weight of cyclohexane is used as the calculation basis, the weight content of water is 225 ppm, Al / Fe=196, and after sufficient stirring, ethylene is introduced to start the polymerization reaction;

[0189] (4) Maintain the ethylene pressure at 1 MPa and react at a reaction temperature of 50 °C for 30 minutes;

[0190] (5) Stop the reaction, take out a small amount of the reaction product and analyze it by gas chromatography (GC). The specific analysis results are shown in Table 3.

[0191] Example 3-2

[0192] The difference from Example 3-1 is only that "based on the weight of cyclohexane, the weight content of water is 100 ppm".

[0193] After the reaction stops, take out a small amount of the reaction product and analyze it by gas chromatography (GC). The specific analysis results are shown in Table 3.

[0194] Example 3-3

[0195] The difference from Example 3-1 is only that "based on the weight of cyclohexane, the weight content of water is 150 ppm".

[0196] After the reaction stops, take out a small amount of the reaction product and analyze it by gas chromatography (GC). The specific analysis results are shown in Table 3.

[0197] Example 3-4

[0198] The difference from Example 3-1 is only that "based on the weight of cyclohexane, the weight content of water is 300 ppm".

[0199] After the reaction stops, take out a small amount of the reaction product and analyze it by gas chromatography (GC). The specific analysis results are shown in Table 3.

[0200] Example 3-5

[0201] The difference from Example 3-1 is only that "based on the weight of cyclohexane, the weight content of water is 500 ppm".

[0202] After the reaction stops, take out a small amount of the reaction product and analyze it by gas chromatography (GC). The specific analysis results are shown in Table 3.

[0203] Example 3-6

[0204] The difference from Example 3-1 is only that "chloro-2-isobutyryl-1,10-phenanthroline-2,6-diethylaniline iron(II) complex" is used to replace "chloro-2-isobutyryl-1,10-phenanthroline-2,6-dimethylaniline iron(II) complex" in Example 1.

[0205] After the reaction stops, take out a small amount of the reaction product and analyze it by gas chromatography (GC). The specific analysis results are shown in Table 3.

[0206] Examples 3-7

[0207] It is only different from Example 3-1 in that "the reaction temperature is 10°C".

[0208] After the reaction 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 3.

[0209] Examples 3-8

[0210] It is only different from Example 3-1 in that "the reaction temperature is 30°C".

[0211] After the reaction 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 3.

[0212] Examples 3-9

[0213] It is only different from Example 3-1 in that "the reaction temperature is 40°C".

[0214] After the reaction 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 3.

[0215] Examples 3-10

[0216] It is only different from Example 3-1 in that "the reaction temperature is 45°C".

[0217] After the reaction 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 3.

[0218] Examples 3-11

[0219] It is only different from Example 3-1 in that "the reaction temperature is 55°C".

[0220] After the reaction 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 3.

[0221] Examples 3-12

[0222] It is only different from Example 3-1 in that "the reaction temperature is 60°C".

[0223] After the reaction 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 3.

[0224] Examples 3-13

[0225] It is only different from Example 3-1 in that "the reaction temperature is 70°C".

[0226] After the reaction 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 3.

[0227] Examples 3 - 14

[0228] The difference from Example 3 - 1 is only that "the reaction temperature is 80 °C".

[0229] After the reaction 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 3.

[0230] Comparative Example 3 - 1

[0231] "Toluene" was used to replace "cyclohexane" in Example 3 - 1.

[0232] After the reaction 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 3.

[0233] Comparative Example 3 - 2

[0234] "Xylene" was used to replace "cyclohexane" in Example 3 - 1.

[0235] After the reaction 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 3.

[0236] Comparative Example 3 - 3

[0237] "Ethanol" was used to replace "cyclohexane" in Example 3 - 1.

[0238] After the reaction 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 3.

[0239] Comparative Example 3 - 4

[0240] "Methylcyclohexane" was used to replace "cyclohexane" in Example 3 - 1.

[0241] After the reaction 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 3.

[0242] Comparative Example 3 - 5

[0243] "Methylaluminoxane" was used to replace "triethylaluminum" in Example 3 - 1.

[0244] After the reaction 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 3.

[0245] Comparative Example 3 - 6

[0246] Replace "triethylaluminum" in Example 3-1 with "methylaluminoxane" and adjust Al / Fe to 1000.

[0247] After the reaction 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 3.

[0248] Table 3

[0249]

[0250]

[0251] Note: In the above table, k refers to the product distribution coefficient.

[0252] As can be seen from the data in Table 3 above,

[0253] First, the catalyst composition provided by the present invention has very high oligomerization reaction activity. When ethylene oligomerization reaction is carried out in the presence of the catalyst composition provided by the present invention, the oligomerization reaction can be rapidly initiated;

[0254] Second, the content of unwanted C4 impurities in the oligomerization product is less, and the product distribution coefficient is relatively high, indicating that the reaction system initiated by the catalyst composition provided by the present invention operates stably and has good repeatability;

[0255] Third, the catalyst composition provided by the present invention can carry out the reaction at a relatively high reaction temperature. This relatively high reaction temperature is easier to achieve than the reaction temperature of 30°C to 40°C commonly used in the art. Moreover, as a result, condensed water can be used as the reaction heat removal medium, which reduces the energy consumption compared with using chilled water as the reaction heat removal medium when the reaction temperature is 30°C to 40°C, and the industrial application value is significantly improved;

[0256] Fourth, as the reaction temperature increases, the catalyst composition provided by the present invention still maintains very high activity, and at a relatively high temperature of 60°C to 70°C, the product distribution coefficient can still reach about 0.7 without a significant decrease.

[0257] It should be noted that the above-described embodiments are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described by referring to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words rather than limiting words. Modifications can be made to the present invention within the scope of the claims of the present invention as provided, and the present invention can be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A catalyst system for ethylene oligomerization, comprising: Iron(II) complex of 2-C1-C6 acyl-1,10-phenanthroline condensed-2,6-dimethylaniline chloride shown in formula (1), an aluminum-containing cocatalyst, water, and cyclohexane; In formula (1), R is selected from C1-C6 alkyl groups; R1-R6 are the same or different and are each independently selected from hydrogen, C1-C6 alkyl groups, halogens, C1-C6 alkoxy groups, and nitro groups; In the catalyst composition, based on the total weight of the cyclohexane, the weight content of the water is 200 ppm to 250 ppm.

2. The catalyst system according to claim 1, wherein In the catalyst composition, based on the total weight of the cyclohexane, the weight content of the water is 210 ppm to 240 ppm.

3. The catalyst system according to claim 2, wherein In the catalyst composition, based on the total weight of the cyclohexane, the weight content of the water is 210 ppm to 230 ppm.

4. The catalyst system according to claim 3, characterized in that, In the catalyst composition, based on the total weight of the cyclohexane, the weight content of the water is 220 ppm to 230 ppm.

5. The catalyst system according to any one of claims 1-4, characterized in that, The aluminum-containing cocatalyst is selected from alkylaluminum compounds.

6. The catalyst system according to claim 5, characterized in that, The aluminum-containing cocatalyst is selected from at least one of the alkylaluminum compounds shown in formula (2), AlR 7n X m Formula (2), In formula (2), R7 is each independently a linear or branched C1-C8 alkyl group; X is a halogen; n is an integer from 1 to 3, m is an integer from 0 to 2, and m + n equals 3.

7. The catalyst system according to claim 6, characterized in that, X is chlorine or bromine.

8. The catalyst system according to claim 6, characterized in that, The alkylaluminum compound is selected from at least one of trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, and ethylaluminum dichloride.

9. The catalyst system according to claim 8, wherein The alkylaluminum compound is selected from triethylaluminum.

10. The catalyst system according to any one of claims 1-4, characterized in that, In formula (1), R is selected from C1-C4 linear alkyl groups, C3-C5 branched alkyl groups, and C3-C5 cycloalkyl groups; and / or, R1-R6 are the same or different and are each independently selected from hydrogen, C1-C4 alkyl groups, halogens, C1-C4 alkoxy groups, and nitro groups.

11. The catalyst system according to claim 10, wherein In formula (1), R is selected from methyl, ethyl, propyl, 1-methylethyl, n-butyl, isobutyl, secondary butyl, and tertiary butyl; and / or, R1-R6 are the same or different and are each independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, fluorine, chlorine, bromine, methoxy, ethoxy, and nitro.

12. The catalyst system according to claim 11, wherein, In formula (1), R is selected from methyl, ethyl, propyl, and 1-methylethyl.

13. The catalyst system according to any one of claims 1-4, characterized in that, In the catalyst system, based on the total volume of the cyclohexane, the content of the iron(II) complex of 2-C1-C6 acyl-1,10-phenanthroline condensed-2,6-dimethylaniline chloride shown in formula (1) is 1 μmol / L to 500 μmol / L.

14. The catalyst system according to claim 13, wherein In the catalyst system, based on the total volume of the cyclohexane, the content of the iron(II) complex of 2-C1-C6 acyl-1,10-phenanthroline condensed-2,6-dimethylaniline chloride shown in formula (1) is 10 μmol / L to 300 μmol / L.

15. The catalyst system according to claim 14, wherein, In the catalyst system, based on the total volume of the cyclohexane, the content of the iron(II) complex of 2-C1-C6 acyl-1,10-phenanthroline condensed-2,6-dimethylaniline chloride shown in the formula (1) is 10 μmol / L to 100 μmol / L.

16. The catalyst system according to any one of claims 1-4, characterized in that, In the catalyst system, the molar ratio of aluminum in the aluminum-containing cocatalyst to iron(II) in the iron(II) complex of 2-C1-C6 acyl-1,10-phenanthroline condensed-2,6-dimethylaniline chloride shown in the formula (1) is 30:1 to less than 900:

1.

17. The catalyst system according to claim 16, wherein In the catalyst system, the molar ratio of aluminum in the aluminum-containing cocatalyst to iron(II) in the iron(II) complex of 2-C1-C6 acyl-1,10-phenanthroline condensed-2,6-dimethylaniline chloride shown in the formula (1) is 100:1 to 700:

1.

18. The catalyst system according to claim 17, wherein In the catalyst system, the molar ratio of aluminum in the aluminum-containing cocatalyst to iron(II) in the iron(II) complex of 2-C1-C6 acyl-1,10-phenanthroline condensed-2,6-dimethylaniline chloride shown in the formula (1) is 148:1 to 196:

1.

19. A method for preparing a catalyst system according to any one of claims 1-18, comprising: The catalyst system is prepared by bringing the iron(II) complex of 2-C1-C6 acyl-1,10-phenanthroline condensed-2,6-dimethylaniline chloride shown in the formula (1), the aluminum-containing cocatalyst, the water and the cyclohexane into contact.

20. Use of the catalyst system according to any one of claims 1-18 in the ethylene oligomerization reaction.

21. The application according to claim 20, wherein Bring a raw material stream containing ethylene into contact with the catalyst system.

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