A process for the selective oligomerization of ethylene

Abstract

The application discloses a method for selectively oligomerizing ethylene. The method comprises the following steps: filling ethylene into a reaction kettle which is replaced by nitrogen, adjusting temperature and pressure to reaction temperature and reaction pressure; adding a main catalyst and a cocatalyst composition into the reaction kettle to carry out an ethylene oligomerization reaction; after the reaction is completed, temperature and pressure are reduced, and a termination agent is used to terminate the reaction; the molar ratio of total boron and aluminum in the main catalyst and the cocatalyst composition is 1:0.1-7000; the main catalyst is formed by a ligand and a transition metal compound, and the molar ratio of the ligand and the transition metal compound is 0.5-1.5:1. The cocatalyst composition comprises an organic boron compound, an alkyl aluminum compound and an alkyl aluminum oxide compound.

Description

Technical Field

[0001] This invention relates to the field of olefin catalytic polymerization technology, and specifically to a method for selective oligomerization of ethylene. Background Technology

[0002] The demand for 1-hexene and 1-octene as comonomers for the preparation of polyolefins continues to grow. Selective oligomerization of ethylene can selectively generate 1-hexene or 1-octene, offering advantages such as good atom economy and simple process routes.

[0003] Patent application CN108607612A describes the use of a mixture of DMAO and AlEt3 as a cocatalyst, which achieves a 1-octene selectivity of 83.8% and an activity of 675577 g / g Cr / h under an ethylene pressure of 4 MPa; however, there is still room for optimization of the 1-octene selectivity.

[0004] Patent CN110449186A discloses a catalyst system with PSiOSiP as the framework, which still uses DMAO and AlEt3 as a co-catalyst to achieve highly selective trimerization and tetramerization; however, there is still room for optimization in the selectivity and other properties of the 1-octene catalyst. Summary of the Invention

[0005] The purpose of this invention is to provide a method for selective oligomerization of ethylene, which catalyzes the trimerization and tetramerization of ethylene with high selectivity and improves the selectivity of 1-hexene and 1-octene.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for selective oligomerization of ethylene, comprising the following steps:

[0008] Ethylene is introduced into the nitrogen-purged reactor, and the temperature and pressure are adjusted to the reaction temperature and pressure.

[0009] A combination of a main catalyst and a co-catalyst is added to the reactor to carry out an ethylene oligomerization reaction;

[0010] After the reaction is complete, cool down and depressurize, then terminate the reaction with a terminator.

[0011] The molar ratio of total boron to aluminum in the main catalyst and co-catalyst composition is 1:0.1 to 7000; preferably 1:0.1 to 2000, more preferably 1:25 to 500;

[0012] The main catalyst is formed by a ligand and a transition metal compound, wherein the molar ratio of the ligand to the transition metal compound is 0.5 to 1.5:1; more preferably 1.05:1.

[0013] The cocatalyst composition includes: organoboron compounds, alkylaluminum compounds, and alkylaluminoxane compounds.

[0014] According to the ethylene selective oligomerization method of the present invention, preferably, the molar ratio of the organoboron compound, the alkylaluminum compound and the alkylaluminoxane compound is (1-20):(10-1000):(50-500); more preferably, (1-2):(40-100):(150-400); and even more preferably, (1-2):(45-95):(180-400).

[0015] According to the selective oligomerization method of ethylene of the present invention, preferably, the reaction temperature is 15-100°C and the reaction pressure is 0.1 MPa-50 MPa.

[0016] According to the selective oligomerization method of ethylene of the present invention, preferably, the reaction temperature is 30-80°C and the reaction pressure is 0.1 MPa-20 MPa.

[0017] According to the ethylene selective oligomerization method of the present invention, preferably, the organoboron compound is selected from one or more combinations of N,N-dimethylaniline tetra(pentafluorophenyl)borate, triphenyltetra(pentafluorophenyl)borate, N,N-dihexylphenylammonium tetra(pentafluorophenyl)borate, N,N-dioctylphenylammonium tetra(pentafluorophenyl)borate, N,N-di(octadecyl)(2,4,6-trimethylphenylammonium)tetra(pentafluorophenyl)borate, N,N-di(dodecyl)phenylammonium tetra(pentafluorophenyl)borate and N-methyl-N-dodecylphenylammonium tetra(pentafluorophenyl)borate;

[0018] The alkylaluminum compound is selected from one or more combinations of trimethylaluminum, triethylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, diethylaluminum chloride, and triethylaluminum chloride.

[0019] The alkylaluminoxane compound is selected from one or more combinations of methylaluminoxane (MAO), methylaluminoxane with volatile components removed (DMAO), modified methylaluminoxane, ethylaluminoxane, and isobutylaluminoxane.

[0020] In the ethylene selective oligomerization method of the present invention, preferably, the organoboron compound is triphenyltetra(pentafluorophenyl)borate; the alkylaluminum compound is triisobutylaluminum; and the alkylaluminoxane compound is methylaluminoxane.

[0021] In the ethylene selective oligomerization method according to the present invention, preferably, the ligand is selected from PNP, PCCP, PCSiP, PNSiP or SNS.

[0022] According to the ethylene selective oligomerization method of the present invention, preferably, the transition metal in the transition metal compound is selected from one or more combinations of chromium, molybdenum, tungsten, cobalt, titanium, tantalum, vanadium, zirconium, iron, nickel and palladium.

[0023] According to the ethylene selective oligomerization method of the present invention, preferably, the transition metal compound is selected from one or more combinations of chromium chloride, chromium acetylacetone, chromium n-octanoate, chromium isooctanoate, chromium diisoprene, chromium diphenyl chromium, chromium tetrahydrofuran dichloride, chromium tetrahydrofuran trichloride, chromium 2-ethylhexanoate, chromium hexacarbonyl, and chromium (benzene)tricarbonyl.

[0024] According to the ethylene selective oligomerization method of the present invention, preferably, the reaction time of the ethylene oligomerization reaction is 20 min to 50 min; more preferably, it is 20 min to 40 min.

[0025] According to the selective oligomerization method of ethylene of the present invention, preferably, the terminating agent is acidified ethanol with a mass fraction of 5-20%; more preferably, it is acidified ethanol with a mass fraction of 5-15%.

[0026] According to the ethylene selective oligomerization method of the present invention, preferably, the nitrogen purging process before the reactor is filled with ethylene includes: evacuating the reactor under heating conditions and purging the gas in the reactor with nitrogen several times.

[0027] According to the ethylene selective oligomerization method of the present invention, preferably, the vacuum treatment time is 20 min to 60 min; more preferably, it is 30 min to 40 min.

[0028] According to the ethylene selective oligomerization method of the present invention, preferably, the reactor is one of a quartz, glass or stainless steel reactor with a volume of 0.1L to 5L.

[0029] According to the ethylene selective oligomerization method of the present invention, preferably, the reaction is cooled by an ice-water bath after completion.

[0030] In the ethylene selective oligomerization method of this invention, the ethylene oligomerization activity of the catalyst is improved. This invention improves the co-catalyst, enabling better coordination with the main catalyst, altering the steric hindrance and electronic effects of the catalyst structure, thus resulting in higher catalytic activity. Specifically, the co-catalyst of this invention employs a combination of alkylaluminum compounds, alkylaluminoxane compounds, and organoboron compounds. All three co-catalysts promote the catalytic performance of the catalyst. For example, the most widely accepted structure of MAO is a three-dimensional cage structure, where the Me bonded to Al can interact with the active center, transforming the pre-catalyst into a catalytically active species. iBu3Al is an alkylating agent that can directly alkylate the active center, which is also a feasible activation method. Boron promoters possess weakly coordinating anions, which can form cation-anion pairs with the catalyst, beneficial for improving catalyst activity. When the three are used in combination, iBu3Al preferentially inserts into the three-dimensional cage structure of MAO, further facilitating its binding with the active center. Through the synergistic effect of the boron promoter, the catalyst performance is effectively improved, thereby enhancing the ethylene oligomerization activity of the catalyst and increasing the selectivity for 1-hexene and 1-octene. Detailed Implementation

[0031] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0032] All numerical specifications in this invention (e.g., temperature, time, concentration, and weight, including ranges for each) are generally approximate values ​​that may be changed (+) or (-) in increments of 0.1 or 1.0. All numerical specifications are to be understood as being preceded by the term "about".

[0033] Example 1

[0034] This embodiment uses the catalyst system of the present invention to catalyze the selective oligomerization reaction of ethylene. The preparation of the main catalyst and the selective oligomerization process of ethylene are as follows:

[0035] The ligand NMe(P(C6H4OMe-2)2)2(PNP) was prepared using a literature method (refer to WO0204119A1). Methylcyclohexane (2.4 μmol) and CrCl3(THF)3 (2.52 μmol), which had been dehydrated by a purification system, were added to a 100 mL reaction tube purged with nitrogen. The reaction was carried out at room temperature for a period of time to obtain the main catalyst.

[0036] A 100 mL glass reactor was connected and evacuated for 30 min under heating conditions. After several nitrogen purgings, ethylene was introduced, and the temperature was adjusted to the reaction temperature of 50 °C. The dehydrated main catalyst and co-catalyst composition was added to the reactor. The molar ratio of the main catalyst to the co-catalyst was 1:250, and the molar ratio of each component in the co-catalyst composition was triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane = 2.64:120:480. Ethylene oligomerization was carried out at 50 °C and 1.0 MPa ethylene pressure. After 30 min of reaction, the reactor was cooled and depressurized using an ice-water bath, and then the reaction was terminated with 10% (w / w) acidified ethanol. The catalyst activity and the distribution of oligomer products are shown in Table 1, and the experimental conditions are shown in Table 2.

[0037] Example 2

[0038] This embodiment uses the catalyst system of the present invention to catalyze the selective oligomerization reaction of ethylene. The preparation of the main catalyst and the selective oligomerization process of ethylene are as follows:

[0039] The ligand Ph2PN was prepared using methods described in the literature. i Pr)PPh2(PNP) (refer to US2006229480A1), methylcyclohexane (dehydrated by a purification system), CrCl3(THF)3 (24 μmol), and the ligand Ph2PN (PNP) were added to a 100 mL reaction tube purged with nitrogen. i The main catalyst was obtained by reacting Pr)PPh2 (25.2 μmol) at room temperature for a period of time.

[0040] A 100 mL glass reactor was connected and evacuated for 30 min under heating conditions. After several nitrogen purgings, ethylene was introduced, and the temperature was adjusted to the reaction temperature of 50 °C. The dehydrated main catalyst and co-catalyst composition was added to the reactor. The molar ratio of the main catalyst to the co-catalyst was 1:25, and the molar ratio of each component in the co-catalyst composition was triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane = 2.64:120:480. Ethylene oligomerization was carried out at 50 °C and 1.0 MPa ethylene pressure. After 30 min of reaction, the reactor was cooled and depressurized using an ice-water bath, and then the reaction was terminated with 10% (w / w) acidified ethanol. The catalyst activity and the distribution of oligomer products are shown in Table 1, and the experimental conditions are shown in Table 2.

[0041] Example 3

[0042] This embodiment uses the catalyst system of the present invention to catalyze the selective oligomerization reaction of ethylene. The preparation of the main catalyst and the selective oligomerization process of ethylene are as follows:

[0043] The ligand Ph2PN(Cp)PPh2(PNP) was prepared (refer to Journal of Molecular Catalysis A: Chemical, 259(2006): 161–165.). Methylcyclohexane (4.8 μmol) and CrCl3(THF)3 (5.04 μmol), which had been dehydrated by a purification system, were added to a 100 mL reaction tube purged with nitrogen. The reaction was carried out at room temperature for a period of time to obtain the main catalyst.

[0044] A 100 mL glass reactor was connected and evacuated for 30 min under heating conditions. After several nitrogen purgings, ethylene was introduced, and the temperature was adjusted to the reaction temperature of 50 °C. The dehydrated main catalyst and co-catalyst composition was added to the reactor. The molar ratio of the main catalyst to the co-catalyst was 1:125, and the molar ratio of each component in the co-catalyst composition was triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane = 2.64:120:480. Ethylene oligomerization was carried out at 50 °C and 1.0 MPa ethylene pressure. After 30 min of reaction, the reactor was cooled and depressurized using an ice-water bath, and then the reaction was terminated with 10% (w / w) acidified ethanol. The catalyst activity and the distribution of oligomer products are shown in Table 1, and the experimental conditions are shown in Table 2.

[0045] Example 4

[0046] This embodiment uses the catalyst system of the present invention to catalyze the selective oligomerization reaction of ethylene. The preparation of the main catalyst and the selective oligomerization process of ethylene are as follows:

[0047] The ligand (EtSCH2CH2)2NH(SNS) was prepared by a literature method (refer to J.Am.Chem.Soc.,2003,125(18):5272-5273.). Methylcyclohexane (dehydrated by a purification system), CrCl3(THF)3 (12 μmol), and the ligand (EtSCH2CH2)2NH (12.6 μmol) were added to a 100 mL reaction tube purged with nitrogen. The reaction was carried out at room temperature for a period of time to obtain the main catalyst.

[0048] A 100 mL glass reactor was connected and evacuated for 30 min under heating conditions. After several nitrogen purgings, ethylene was introduced, and the temperature was adjusted to the reaction temperature of 50 °C. The dehydrated main catalyst and co-catalyst composition was added to the reactor. The molar ratio of the main catalyst to the co-catalyst was 1:50, and the molar ratio of each component in the co-catalyst composition was triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane = 2.64:120:480. Ethylene oligomerization was carried out at 50 °C and 1.0 MPa ethylene pressure. After 30 min of reaction, the reactor was cooled and depressurized using an ice-water bath, and then the reaction was terminated with 10% (w / w) acidified ethanol. The catalyst activity and the distribution of oligomer products are shown in Table 1, and the experimental conditions are shown in Table 2.

[0049] Example 5

[0050] This embodiment uses the catalyst system of the present invention to catalyze the selective oligomerization reaction of ethylene. The preparation of the main catalyst and the selective oligomerization process of ethylene are as follows:

[0051] The ligand Ph2PN was prepared using methods described in the literature. i Pr)P(Ph)N( i Pr)H(PNP) (refer to US2010 / 190939), methylcyclohexane (dehydrated by a purification system), CrCl3(THF)3 (1.2 μmol), and the ligand Ph2PN (Pr)H(PNP) (see US2010 / 190939) were added to a 100 mL reaction tube purged with nitrogen. i Pr)P(Ph)N( i The main catalyst was obtained by reacting Pr)H (1.26 μmol) at room temperature for a period of time.

[0052] A 100 mL glass reactor was connected and evacuated for 30 min under heating conditions. After several nitrogen purgings, ethylene was introduced, and the temperature was adjusted to the reaction temperature of 50 °C. The dehydrated main catalyst and co-catalyst composition was added to the reactor. The molar ratio of the main catalyst to the co-catalyst was 1:500, and the molar ratio of each component in the co-catalyst composition was triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane = 2.64:120:480. Ethylene oligomerization was carried out at 50 °C and 1.0 MPa ethylene pressure. After 30 min of reaction, the reactor was cooled and depressurized using an ice-water bath, and then the reaction was terminated with 10% (w / w) acidified ethanol. The catalyst activity and the distribution of oligomer products are shown in Table 1, and the experimental conditions are shown in Table 2.

[0053] Example 6

[0054] NMe(P(C6H4OMe-2)2)2 was used as the ligand, and the molar ratio of the ligand to the transition metal compound was 1.05:1. The molar ratio of each component in the co-catalyst composition was triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane = 2.64:120:480. The catalyst activity and the distribution of oligomers are shown in Table 1, and the experimental conditions are shown in Table 2.

[0055] Example 7

[0056] Ph2PN ( i Pr)PPh2 is the ligand, and the molar ratio of the ligand to the transition metal compound is 1.05:1. The molar ratio of each component in the co-catalyst composition is triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane = 2.64:120:480. The catalyst activity and the distribution of oligomers are shown in Table 1, and the experimental conditions are shown in Table 2.

[0057] Example 8

[0058] Ph2PN(Cp)PPh2 was used as the ligand, and the molar ratio of the ligand to the transition metal compound was 1.05:1. The molar ratio of each component in the co-catalyst composition was triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane = 2.64:120:480. The catalyst activity and the distribution of oligomers are shown in Table 1, and the experimental conditions are shown in Table 2.

[0059] Example 9

[0060] (EtSCH2CH2)2NH was used as the ligand, and the molar ratio of the ligand to the transition metal compound was 1.05:1. The molar ratio of each component in the cocatalyst composition was triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane = 2.64:120:480. The catalyst activity and the distribution of oligomers are shown in Table 1, and the experimental conditions are shown in Table 2.

[0061] Example 10

[0062] Ph2PN ( i Pr)P(Ph)N( i Pr)H is the ligand, and the molar ratio of the ligand to the transition metal compound is 1.05:1. The molar ratio of each component in the co-catalyst composition is triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane = 2.64:120:480. The catalyst activity and the distribution of oligomers are shown in Table 1, and the experimental conditions are shown in Table 2.

[0063] Example 11

[0064] Same as Example 1, except that triisobutylaluminum was replaced with trimethylaluminum. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 4.

[0065] Example 12

[0066] Same as Example 2, except that methylaluminoxane was replaced with isobutylaluminoxane and triisobutylaluminum was replaced with triethylaluminum. The catalyst activity and the distribution of oligomers are shown in Table 1, and the experimental conditions are shown in Table 4.

[0067] Example 13

[0068] Same as Example 3, except that methylaluminoxane was replaced with modified methylaluminoxane, and triphenyltetra(pentafluorophenyl)borate was replaced with N,N-dimethylanilinetetra(pentafluorophenyl)borate. The catalyst activity and the distribution of oligomers are shown in Table 1, and the experimental conditions are shown in Table 4.

[0069] Example 14

[0070] Same as Example 4, except that triisobutylaluminum was replaced with triethylaluminum. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 4.

[0071] Example 15

[0072] Same as Example 5, except that methylaluminoxane was replaced with modified methylaluminoxane and triisobutylaluminum was replaced with triethylaluminum. The catalyst activity and the distribution of oligomers are shown in Table 1, and the experimental conditions are shown in Table 4.

[0073] Comparative Example 1a

[0074] Same as Example 1. The difference is that boron (B) auxiliary and triisobutylaluminum were not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0075] Comparative Example 1b

[0076] Same as Example 1. The difference is that boron (B) auxiliary was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0077] Comparative Example 1c

[0078] Same as Example 1. The difference is that triisobutylaluminum was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0079] Comparative Example 1d

[0080] Same as Example 1. The difference is that aluminum oxane was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0081] Example 1e

[0082] Same as Example 1, except that the ratio of triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane was adjusted to 264:120:480. The catalyst activity and the distribution of oligomers are shown in Table 1, and the experimental conditions are shown in Table 2.

[0083] Comparative Example 2a

[0084] Same as Example 2. The difference is that boron (B) auxiliary and triisobutylaluminum were not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0085] Comparative Example 2b

[0086] Same as Example 2. The difference is that boron (B) auxiliary was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0087] Comparative Example 2c

[0088] Same as Example 2. The difference is that triisobutylaluminum was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0089] Comparative Example 2d

[0090] Same as Example 2. The difference is that aluminum oxane was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0091] Example 2e

[0092] Same as Example 2, except that the ratio of triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane was adjusted to 2.64:12000:480. The catalyst activity and the distribution of oligomers are shown in Table 1, and the experimental conditions are shown in Table 2.

[0093] Comparative Example 3a

[0094] Same as Example 3. The difference is that boron (B) auxiliary and triisobutylaluminum were not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0095] Comparative Example 3b

[0096] Same as Example 3. The difference is that boron (B) auxiliary was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0097] Comparative Example 3c

[0098] Same as Example 3. The difference is that triisobutylaluminum was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0099] Comparative 3D

[0100] Same as Example 3. The difference is that aluminum oxane was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0101] Example 3e

[0102] Same as Example 3, except that the ratio of triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane was adjusted to 2.64:120:48000. The catalyst activity and the distribution of oligomers are shown in Table 1, and the experimental conditions are shown in Table 2.

[0103] Comparative Example 4a

[0104] Same as Example 4. The difference is that boron (B) auxiliary and triisobutylaluminum were not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0105] Comparative Example 4b

[0106] Same as Example 4. The difference is that boron (B) auxiliary was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0107] Comparative Example 4c

[0108] Same as Example 4. The difference is that triisobutylaluminum was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0109] Comparative Example 4d

[0110] Same as Example 4. The difference is that aluminum oxane was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0111] Example 4e

[0112] Same as Example 4, except that the ratio of triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane was adjusted to 2.64:12000:480. The catalyst activity and the distribution of oligomers are shown in Table 1, and the experimental conditions are shown in Table 2.

[0113] Comparative Example 5a

[0114] Same as Example 5. The difference is that boron (B) auxiliary and triisobutylaluminum were not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0115] Comparative Example 5b

[0116] Same as Example 5. The difference is that boron (B) auxiliary was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0117] Comparative Example 5c

[0118] Same as Example 5. The difference is that triisobutylaluminum was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0119] Comparative Example 5d

[0120] Same as Example 5. The difference is that aluminum oxane was not used. Catalyst activity and oligomer distribution are shown in Table 1, and experimental conditions are shown in Table 3.

[0121] Example 5e

[0122] Same as Example 5, except that the ratio of triphenyltetra(pentafluorophenyl)borate:triisobutylaluminum:methylaluminoxane was adjusted to 264:120:480. The catalyst activity and the distribution of oligomers are shown in Table 1, and the experimental conditions are shown in Table 2.

[0123] As shown in Tables 1-4, within the scope claimed in the claims of this invention, the ethylene selective oligomerization method of this invention can achieve good α-olefin selectivity, and the catalytic system used has good catalytic activity. When one or more co-catalysts are missing, the effect described in the patent cannot be effectively achieved.

[0124] Compared with Comparative Examples 1a-1d, Example 2 with Comparative Examples 2a-2d, Example 3 with Comparative Examples 3a-3d, Example 4 with Comparative Examples 4a-4d, and Example 5 with Comparative Examples 5a-5d, Examples 1-5 exhibit higher catalytic activity and α-olefin selectivity (1-C8 / C8).

[0125] A comparison of Example 1 with Comparative Example 1e, Example 2 with Comparative Example 2e, Example 3 with Comparative Example 3e, Example 4 with Comparative Example 4e, and Example 5 with Comparative Example 5e shows that when certain components in the co-catalyst exceed the specified range, both the catalytic activity and the α-olefin selectivity decrease.

[0126] Table 1 Catalyst activity and oligomer activity

[0127] Example <![CDATA[Activity 10 5 g / mol Cr / h]]> <![CDATA[C4]]> <![CDATA[C6]]> <![CDATA[1-C6]]> <![CDATA[C8]]> <![CDATA[1-C8]]> <![CDATA[C 10+ ]]> Example 1 36.29 0.67 82.51 81.46 5.48 5.02 11.34 Comparative Example 1a 9.81 0.95 90.32 89.56 1.67 1.67 7.06 Comparative Example 1b 3.12 0.33 79.23 77.11 10.11 9.89 10.33 Comparative Example 1c 4.53 0.64 82.12 81.23 11.34 10.31 5.90 Comparative Example 1d 8.12 1.23 81.89 80.15 8.18 7.89 8.70 Comparative Example 1e 28.76 0.32 65.78 64.23 10.74 9.45 23.16 Example 2 56.12 2.78 24.67 23.76 35.29 32.11 37.26 Comparative Example 2a 23.67 2.31 25.65 24.51 28.97 27.68 43.07 Comparative Example 2b 19.88 3.41 26.11 24.14 29.31 28.89 41.17 Comparative Example 2c 17.86 2.56 23.45 22.64 30.77 28.74 43.22 Comparative Example 2d 20.11 4.21 26.73 25.98 33.12 31.97 35.94 Comparative Example 2e 39.67 1.89 30.85 28.34 22.74 20.15 44.52 Example 3 36.56 0.97 33.46 32.89 58.99 57.68 6.58 Comparative Example 3a 28.79 0.74 33.17 26.68 50.87 45.08 15.22 Comparative Example 3b 24.67 0.99 34.67 30.23 50.11 46.89 14.23 Comparative Example 3c 29.88 1.02 31.65 28.79 48.76 44.65 18.57 Comparative 3D 20.14 1.34 32.84 29.88 49.81 48.23 16.01 Comparative Example 3e 23.78 0.67 31.82 28.97 49.92 48.93 17.59 Example 4 87.06 1.45 93.78 92.09 2.98 2.57 1.79 Comparative Example 4a 30.67 1.58 91.89 90.67 1.45 1.03 5.08 Comparative Example 4b 30.12 1.23 90.34 89.34 2.84 2.46 5.59 Comparative Example 4c 33.87 1.90 92.22 91.48 2.45 2.07 3.43 Comparative Example 4d 13.89 0.92 89.45 87.55 1.87 1.56 7.76 Comparative Example 4e 45.83 1.05 88.76 86.44 3.77 3.24 6.42 Example 5 20.67 1.49 69.87 68.57 12.67 10.98 15.97 Comparative Example 5a 10.45 4.78 65.45 63.44 8.89 7.62 20.88 Comparative Example 5b 13.56 3.89 60.78 57.46 10.83 8.99 24.50 Comparative Example 5c 10.78 4.08 65.31 62.48 9.64 7.64 20.97 Comparative Example 5d 12.67 3.97 66.82 64.97 10.56 7.92 18.65 Comparative Example 5e 18.68 1.63 63.88 60.14 9.66 8.64 24.83 Example 6 53.57 0.44 81.35 85.26 4.80 4.73 13.41 Example 7 119.91 1.06 16.43 15.61 63.23 62.07 19.28 Example 8 44.57 1.96 13.61 12.95 64.35 63.83 20.08 Example 9 75.53 1.21 75.59 74.16 16.07 15.31 7.13 Example 10 107.81 1.65 67.26 66.17 10.86 9.73 20.23 Example 11 16.35 0.67 78.89 75.56 8.85 7.65 11.59 Example 12 22.02 1.99 19.72 18.97 29.83 27.88 48.46 Example 13 18.11 0.67 30.22 29.88 39.93 38.02 29.18 Example 14 30.74 1.31 89.92 87.43 1.03 0.99 7.74 Example 15 10.63 1.11 68.44 66.34 10.93 9.83 19.52

[0128]

[0129] Table 3 Experimental conditions of Comparative Examples 1a to 5d

[0130]

[0131] Table 4 Experimental conditions of Examples 11 to 15

[0132]

[0133] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for selective oligomerization of ethylene, characterized in that, The method includes the following steps: Ethylene is introduced into the nitrogen-purged reactor, and the temperature and pressure are adjusted to the reaction temperature and pressure. A combination of a main catalyst and a co-catalyst is added to the reactor to carry out an ethylene oligomerization reaction; After the reaction is complete, cool down and depressurize, then terminate the reaction with a terminator. The molar ratio of total boron to aluminum in the main catalyst and co-catalyst composition is 1:0.1 to 7000; The main catalyst is formed by a ligand and a transition metal compound, wherein the molar ratio of the ligand to the transition metal compound is 0.5 to 1.5:1; The cocatalyst composition consists of triphenyltetra(pentafluorophenyl)borate, triisobutylaluminum and methylaluminoxane in a molar ratio of 2.64:120:

480.

2. The method for selective oligomerization of ethylene according to claim 1, characterized in that, The reaction temperature is 15–100℃; the reaction pressure is 0.1 MPa–50 MPa.

3. The method for selective oligomerization of ethylene according to claim 1, characterized in that, The reaction temperature is 30–80℃; the reaction pressure is 0.1 MPa–20 MPa.

4. The method for selective oligomerization of ethylene according to claim 1, characterized in that, The ligands are selected from PNP, PCCP, PCSiP, PNSiP, or SNS.

5. The method for selective oligomerization of ethylene according to claim 1, characterized in that, The transition metal in the transition metal compound is selected from one or more combinations of chromium, molybdenum, tungsten, cobalt, titanium, tantalum, vanadium, zirconium, iron, nickel and palladium.

6. The method for selective oligomerization of ethylene according to claim 5, characterized in that, The transition metal compound is selected from one or more combinations of chromium chloride, chromium acetylacetone, chromium octanoate, chromium isooctanoate, chromium diisoprene, chromium diphenyl chromium, chromium tetrahydrofuran dichloride, chromium tetrahydrofuran trichloride, chromium 2-ethylhexanoate, chromium hexacarbonyl, and chromium (benzene)tricarbonyl.

7. The method for selective oligomerization of ethylene according to claim 1, characterized in that, The reaction time for the ethylene oligomerization reaction is 20 min to 50 min.

8. The method for selective oligomerization of ethylene according to claim 1, characterized in that, The terminator is acidified ethanol with a mass fraction of 5-20%.

9. The method for selective oligomerization of ethylene according to claim 1, characterized in that, The terminator is acidified ethanol with a mass fraction of 5-15%.

10. The method for selective oligomerization of ethylene according to claim 1, characterized in that, The nitrogen purging process before ethylene is introduced into the reactor includes: evacuating the reactor under heating conditions and purging the gas in the reactor with nitrogen several times.

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