Pyridine ring-containing metal complex and preparation method thereof, branched polyethylene and preparation method and application thereof

Abstract

The invention relates to the technical field of polyolefin preparation, in particular to a pyridine ring-containing metal complex and a preparation method thereof, branched polyethylene and a preparation method and application thereof, and the pyridine ring-containing metal complex has a structure as shown in a formula (1). When the metal complex containing the pyridine ring provided by the invention is used for preparing branched polyethylene, the prepared branched polyethylene has proper number-average molecular weight, branching degree and specific branched chain composition proportion, and the branched polyethylene can improve the viscosity-temperature property of lubricating oil as a lubricating oil viscosity index improver. # imgabs0 #

Description

Technical Field

[0001] The invention relates to the technical field of polyolefin preparation, and in particular to a pyridine ring-containing metal complex and a preparation method thereof, and branched polyethylene and a preparation method and application thereof. Background Art

[0002] The viscosity-temperature property of lubricating oil is that the viscosity of lubricating oil decreases with increasing temperature and increases with decreasing temperature. In practical applications, the viscosity-temperature property of lubricating oil is required to be good, that is, the smaller the change of oil viscosity with the working temperature, the better. In order to improve the viscosity-temperature property of lubricating oil, a viscosity index improver is usually added to lubricating oil to obtain a lubricating oil with good starting performance at low temperature and maintaining appropriate viscosity at high temperature.

[0003] Viscosity index improver (VII) is usually a rubbery or viscous oil-soluble polymer with a molecular weight ranging from tens of thousands to hundreds of thousands, while the molecular weight of lubricating oil base oil ranges from hundreds to thousands. When polymers are dissolved in lubricating oil base oil, they form a coil-like structure, and the coil volume of polymers in the solvent is much larger than that of lubricating oils with smaller molecular weights, making the viscosity of the oil much greater than that of the base oil, which is the reason for the thickening effect. At low temperatures, polymers exist in the form of curled coils and have little effect on the viscosity of the oil; as the temperature rises, the coils stretch and the effective volume increases, thereby increasing the obstruction to the flow of the oil, offsetting the change in the viscosity of the lubricating oil due to the increase in temperature, and keeping the viscosity value of the lubricating oil basically unchanged. Viscosity index improvers are based on having different molecular forms at different temperatures and having different effects on viscosity to increase the viscosity of the oil and improve the viscosity-temperature characteristics of the lubricating oil.

[0004] Commonly used viscosity index improvers include ethylene-propylene copolymer (OCP), polyisobutylene (PIB), styrene-butadiene copolymer (HSD), and polymethacrylate (PMA). The viscosity-increasing ability is a very important performance of the viscosity index improver. The greater the viscosity-increasing ability of the viscosity index improver, the less the amount added, and the lower the cost of the multi-grade oil. The viscosity-increasing ability is mainly related to the molecular weight of the viscosity index improver and the main chain carbon number [—CH 2 —] and its form in the base oil. The molecular weight, branching degree and branching form of the viscosity index improver will affect the viscosity-temperature properties of the lubricating oil.

[0005] CN112745411A discloses a branched polyethylene, which is obtained by homopolymerizing ethylene monomers in the presence of a catalyst containing a diimide metal complex. However, the branched polyethylene prepared by the catalyst has a high methyl branch content, and the viscosity-increasing ability of the obtained lubricating oil needs to be further improved. The molecular weight, branching degree and branching form need to be further improved. Summary of the invention

[0006] The purpose of the present invention is to overcome the problem that the branching degree, molecular weight distribution and branching form of branched polyethylene in the prior art need to be improved, and to provide a pyridine ring-containing metal complex and a preparation method thereof, a branched polyethylene and a preparation method and application thereof.

[0007] In order to achieve the above object, the first aspect of the present invention provides a pyridine ring-containing metal complex, wherein the metal complex has a structure shown in formula (1):

[0008]

[0009] Wherein, M is selected from nickel or palladium;

[0010] X is selected from halogen, C1-C4 alkyl, C2-C6 alkenyl, Benzyl;

[0011] R 1 Selected from C1-C8 alkyl, C1-C8 haloalkyl, C3-C8 cycloalkyl, C3-C8 halocycloalkyl, unsubstituted or substituted phenyl;

[0012] R 2 Selected from C3-C8 cycloalkyl, C3-C8 halogenated cycloalkyl;

[0013] R 3 Selected from C1-C5 alkyl, C3-C8 cycloalkyl, halogen, unsubstituted or substituted phenyl, C1-C5 alkoxy, C1-C5 silyl;

[0014] R 4 Selected from C1-C5 alkyl, C3-C8 cycloalkyl, halogen, unsubstituted or substituted phenyl, C1-C5 alkoxy, C1-C5 silyl;

[0015] R 5 Selected from hydrogen, C1-C5 alkyl, C3-C8 cycloalkyl, unsubstituted or substituted phenyl, halogen or C1-C5 alkoxy.

[0016] The second aspect of the present invention provides a method for preparing a metal complex containing a pyridine ring, wherein the method comprises: reacting a ligand having a structure shown in formula (2) with a metal compound MX 2 touch;

[0017]

[0018] Wherein, the ligand of the structure shown in formula (2) and the metal compound MX 2 In, R 1 , R 2 , R 3 , R 4 , R 5 , M and X are as defined in the first aspect of the present invention.

[0019] The third aspect of the present invention provides a metal complex prepared by the method described in the second aspect of the present invention.

[0020] The fourth aspect of the present invention provides a method for preparing branched polyethylene, wherein the preparation method comprises: homopolymerizing ethylene monomer in the presence of a catalyst and a second solvent;

[0021] Wherein, the catalyst contains the metal complex containing a pyridine ring as described in the first aspect of the present invention or the third aspect of the present invention.

[0022] The fifth aspect of the present invention provides a branched polyethylene, wherein in the branched structure of the branched polyethylene, the long branches with carbon atoms of four or more account for 17-55 mol% of the branch ratio;

[0023] Alternatively, the branched polyethylene is prepared by the method described in the fourth aspect of the present invention.

[0024] The sixth aspect of the present invention provides use of the branched polyethylene described in the fifth aspect of the present invention in a lubricating oil viscosity index improver.

[0025] The seventh aspect of the present invention provides a lubricating oil, wherein the lubricating oil comprises the branched polyethylene described in the fifth aspect of the present invention.

[0026] Through the above technical solution, at least the following beneficial effects can be obtained:

[0027] (1) In the presence of a catalyst including a metal complex containing a pyridine ring, ethylene monomer is homopolymerized to obtain a branched polyethylene, wherein the obtained branched polyethylene has a suitable number average molecular weight, a degree of branching and a specific branch chain composition ratio. Such a branched polyethylene can be used as a lubricating oil viscosity index improver to improve the viscosity-temperature property of the lubricating oil.

[0028] (2) Compared with the traditional ethylene-propylene copolymer viscosity index improver and the branched polyethylene disclosed in CN112745411A, the branched polyethylene provided by the present invention has a higher content of long-chain branches with carbon atoms of more than four and a lower content of methyl branches, is easily soluble in base oil, and can reduce the loss of thickening ability.

[0029] (3) Under the catalysis of a metal complex containing a pyridine ring, the obtained branched polyethylene has a specific content of methyl branches and long branches with more than four carbon atoms, and the number average molecular weight and degree of branching have a specific ratio. When used as a viscosity index improver for lubricating oil, it has good viscosity increasing ability and shear resistance, and can effectively improve the viscosity index (VI) of the base oil.

[0030] (4) The method for preparing branched polyethylene provided by the present invention is that the branched polyethylene is directly obtained by homopolymerization of ethylene, and the preparation method is simple. DETAILED DESCRIPTION

[0031] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0032] The first aspect of the present invention provides a pyridine ring-containing metal complex, wherein the metal complex has a structure shown in formula (1):

[0033]

[0034] Wherein, M is selected from nickel or palladium;

[0035] X is selected from halogen, C1-C4 alkyl, C2-C6 alkenyl, allyl Benzyl;

[0036] R 1 Selected from C1-C8 alkyl, C1-C8 haloalkyl, C3-C8 cycloalkyl, C3-C8 halocycloalkyl, unsubstituted or substituted phenyl;

[0037] R 2 Selected from C3-C8 cycloalkyl, C3-C8 halogenated cycloalkyl;

[0038] R 3 Selected from C1-C5 alkyl, C3-C8 cycloalkyl, halogen, unsubstituted or substituted phenyl, C1-C5 alkoxy, C1-C5 silyl;

[0039] R 4 Selected from C1-C5 alkyl, C3-C8 cycloalkyl, halogen, unsubstituted or substituted phenyl, C1-C5 alkoxy, C1-C5 silyl;

[0040] R 5 Selected from hydrogen, C1-C5 alkyl, C3-C8 cycloalkyl, unsubstituted or substituted phenyl, halogen or C1-C5 alkoxy.

[0041] When the pyridine ring-containing metal complex provided by the present invention is used as a catalyst, the molecular weight, molecular weight distribution, degree of branching, proportion of branch chains of different lengths, etc. of the branched polyethylene can be effectively regulated by adjusting the structure, so as to obtain branched polyethylene with different structures.

[0042] In the present invention, the C1-C8 alkyl group can be, for example, any one of a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a n-pentyl group, an isopentyl group, a tert-pentyl group, a neopentyl group, a n-hexyl group, an isohexyl group, a n-heptyl group, an isoheptyl group, a 2-methylhexyl group, a 2-ethylhexyl group, a 1-methylheptyl group, a 2-methylheptyl group, a n-octyl group, an isooctyl group, a n-nonyl group, an isononyl group and a 3,5,5-trimethylhexyl group.

[0043] In the present invention, the C1-C5 alkyl group is selected from the alkyl group with carbon atoms of C1-C5 in the above-mentioned C1-C8 alkyl group.

[0044] In the present invention, the C3-C8 cycloalkyl group may be, for example, any one of cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl.

[0045] In the present invention, the C1-C5 alkoxy group may be, for example, any one of methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy, n-pentoxy, isopentyl, tert-pentyloxy, and neopentyloxy.

[0046] In the present invention, the C1-C5 silyl group may be, for example, any one of a trimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group, a tributylsilyl group, a tripentylsilyl group, and a trihexylsilyl group.

[0047] In the present invention, the C3-C8 halocycloalkyl group may be, for example, a C3-C8 cycloalkyl group substituted by any halogen atom. The definition of the C3-C8 cycloalkyl group is the same as described above. The halogen atom may be any one of fluorine, chlorine, bromine, and iodine, and the substitution position of the halogen is not fixed, for example, the substitution position may be the para position.

[0048] In the present invention, preferably, the R 1 is selected from C1-C8 alkyl, C3-C8 cycloalkyl, unsubstituted or substituted phenyl; in some preferred cases, the R 1 is selected from C1-C5 alkyl, C3-C8 cycloalkyl or phenyl; further preferably, said R 1 Selected from methyl, ethyl, isopropyl, cyclohexyl or phenyl.

[0049] In the present invention, preferably, the R 2The inventors of the present invention have found that when R 2 When selected from C3-C6 cycloalkyl and C3-C6 halogenated cycloalkyl, the pyridine ring-containing metal complex is used as a catalyst, and has better thermal stability, especially under conventional conditions for obtaining branched polyethylene by ethylene homopolymerization. Moreover, it is beneficial to increase the content of long-chain branches with carbon numbers above four in the obtained branched polyethylene.

[0050] In a preferred embodiment of the present invention, the R 2 is selected from C3-C6 cycloalkyl, C3-C6 halogenated cycloalkyl. More preferably, R 2 is selected from cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl or 4-chlorocyclohexyl.

[0051] In the present invention, preferably, the R 3 is selected from C1-C5 alkyl, C3-C8 cycloalkyl, C1-C5 silyl, halogen or phenyl. In some more preferred cases, the R 3 Selected from isopropyl, cyclopropyl, cyclopentyl, cyclohexyl, trimethylsilyl, bromine or phenyl.

[0052] In the present invention, preferably, the R 4 is selected from C1-C5 alkyl, C3-C8 cycloalkyl, C1-C5 silyl, halogen or phenyl. In some more preferred cases, the R 4 Selected from methyl, isopropyl, cyclohexyl, trimethylsilyl, bromine or phenyl.

[0053] In the present invention, preferably, the R 5 is selected from hydrogen, halogen or C1-C3 alkoxy, in some more preferred cases, said R 5 is selected from hydrogen, bromine or methoxy;

[0054] In the present invention, preferably, X is selected from fluorine, chlorine or bromine.

[0055] In some preferred embodiments of the present invention, the R 1 is selected from methyl, ethyl, isopropyl, cyclohexyl or phenyl; said R 2 is selected from cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl or 4-chlorocyclohexyl; said R 3 is selected from isopropyl, cyclopropyl, cyclopentyl, cyclohexyl, trimethylsilyl, bromine or phenyl; said R 4 is selected from methyl, isopropyl, cyclohexyl, trimethylsilyl, bromine or phenyl; said R 5 is selected from hydrogen, bromine or methoxy; X is selected from fluorine, chlorine or bromine, and M is selected from nickel or palladium; when the structure of the metal complex containing a pyridine ring is within this range, the prepared branched polyethylene has a better effect of improving the viscosity-temperature property of the lubricating oil.

[0056] The second aspect of the present invention provides a method for preparing a metal complex containing a pyridine ring, wherein the method comprises: reacting a ligand having a structure shown in formula (2) with a metal compound MX 2 touch;

[0057]

[0058] Wherein, the ligand of the structure shown in formula (2) and the metal compound MX 2 In, R 1 , R 2 , R 3 , R 4 , R 5 , M and X are as defined in the first aspect of the present invention.

[0059] In the present invention, the method for preparing the metal complex containing a pyridine ring has the characteristics of mild conditions and simple operation.

[0060] In the present invention, preferably, the contact temperature is 0-100°C, for example, it can be 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C and any range consisting of any two values ​​therein, more preferably 30-60°C.

[0061] In the present invention, preferably, the contact time is 5-48 h, for example, it can be 5 h, 8 h, 10 h, 12 h, 14 h, 18 h, 24 h, 36 h, 48 h and any value within the range of any two of the above values, more preferably 5-24 h.

[0062] In the present invention, preferably, the molar ratio of the ligand to the metal compound is (0.5-3):1, for example, it can be 0.5:1, 1:1, 2:1, 3:1 and any value within the range of any two of the above values. If the above molar feed ratio is too small, the target product cannot be obtained; if the above molar feed ratio is too large, the raw material will be wasted. In order to save costs, reduce the waste of the ligand and the metal compound, and obtain the target product, more preferably, the molar ratio of the ligand to the metal compound is (1-2):1.

[0063] In the present invention, preferably, the contacting is performed in the presence of a first solvent.

[0064] In the present invention, preferably, the first solvent is an inert solvent. The inert organic solvent refers to a solvent that does not react chemically with any chemical reagent used in the reaction.

[0065] In the present invention, more preferably, the first solvent is at least one selected from toluene, n-hexane, dichloromethane, 1,2-dichloroethane, and chlorobenzene.

[0066] In the present invention, preferably, the first solvent may be a solvent that has been purified to be anhydrous and oxygen-free.

[0067] In the present invention, preferably, the contacting can be performed under an inert atmosphere (such as nitrogen or argon).

[0068] In the present invention, preferably, the contacting may be performed under anhydrous and / or oxygen-free conditions.

[0069] The method for preparing a metal complex containing a pyridine ring according to the present invention may further include post-treatment. The present invention has no particular limitation on the post-treatment as long as it can meet the requirements of the present invention. For example, the post-treatment may be performed in the following manner: extraction is performed with an extraction solvent (such as dichloromethane, ethyl acetate, etc.), the organic phase is retained, and the crude product containing the target product is obtained after drying, filtering, and removing the solvent in sequence, and then further separation and purification (such as distillation, crystallization, recrystallization, thin layer chromatography, column chromatography, etc.) is performed to obtain the target compound.

[0070] In some preferred embodiments of the present invention, in the method for preparing a metal complex containing a pyridine ring, the contact temperature is 30-60°C, the contact time is 5-24h, the molar ratio of the ligand to the metal compound is (1-2):1, and the contact is carried out in the presence of an inert solvent.

[0071] The third aspect of the present invention provides a metal complex prepared by the method described in the second aspect of the present invention.

[0072] The fourth aspect of the present invention provides a method for preparing branched polyethylene, wherein the preparation method comprises: homopolymerizing ethylene monomer in the presence of a catalyst and a second solvent;

[0073] Wherein, the catalyst contains the metal complex containing a pyridine ring as described in the first aspect of the present invention or the third aspect of the present invention.

[0074] In some embodiments of the present invention, the pyridine ring-containing metal complex is prepared in situ or pre-prepared.

[0075] In the present invention, the in-situ preparation may include: the ligand of the structure shown in formula (2) provided in the second aspect of the present invention and the metal compound MX 2 In the presence of , an in situ reaction is performed to generate a pyridine ring-containing metal complex as described in formula (1), and the reaction conditions of the in situ reaction are as described in the second aspect of the present invention.

[0076] In the present invention, preferably, the ethylene monomer comes from the ethylene gas continuously introduced into the reactor, and the pressure of the gas can be adjusted according to actual needs.

[0077] In the present invention, preferably, the second solvent is an inert solvent. The inert organic solvent refers to a solvent that does not chemically react with any chemical reagent used in the homopolymerization reaction in this reaction.

[0078] In the present invention, more preferably, the second solvent is at least one selected from toluene, n-hexane, dichloromethane, 1,2-dichloroethane, and chlorobenzene.

[0079] In the present invention, preferably, the catalyst further contains a co-catalyst.

[0080] In the present invention, preferably, the molar ratio of the metal complex to the co-catalyst is 1:(0.01-10000), for example, it can be 1:0.01, 1:0.02, 1:0.03, 1:0.04, 1:0.05, 1:0.5, 1:1, 1:5, 1:10, 1:20, 1:50, 1:100, 1:200, 1:500, 1:1000, 1:2000, 1:3000, 1:4000, 1:5000, 1:6000, 1:7000, 1:8000, 1:9000, 1:10000 and any value within the range composed of any two of the above values, more preferably 1:(0.1-5000), and further preferably 1:(1-1000).

[0081] In the present invention, the co-catalyst is a substance that can promote the catalytic reaction, for example, it can be selected from at least one of alkyl aluminum and organic boron.

[0082] In the present invention, the alkyl aluminum includes any compound containing a carbon-aluminum bond, for example, it can be selected from at least one of methylaluminoxane (MAO), modified methylaluminoxane (MMAO), trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, diethylaluminum chloride, and ethylaluminum dichloride.

[0083] In the present invention, the organoboron compound includes any compound containing a carbon-boron bond, for example, at least one selected from an organoboron compound of a trisubstituted ammonium salt, an organoboron compound containing a carbonium ion, and an organoboron compound containing a Lewis acid.

[0084] The organic boron compound of the trisubstituted ammonium salt is selected from at least one of N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N-di(hexadecyl)aniline tetrakis(pentafluorophenyl)borate, N,N-dioctadecylaniline tetrakis(pentafluorophenyl)borate, triphenylcarbon tetrakis(pentafluorophenyl)borate and tris(pentafluorophenyl)borane.

[0085] In the present invention, the conditions for the homopolymerization reaction include:

[0086] The temperature of the homopolymerization reaction is 0°C-150°C, for example, it can be 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C and any range consisting of any two values ​​therein, preferably 10-100°C.

[0087] In the present invention, preferably, the homopolymerization reaction can be carried out under a protective atmosphere, and the protective atmosphere is an inert atmosphere (such as nitrogen, argon).

[0088] In the present invention, preferably, the pressure of the homopolymerization reaction is 0.1-10 MPa, for example, it can be 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.8 MPa, 1 MPa, 1.2 MPa, 1.5 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa and any range consisting of any two values ​​therein, more preferably 0.1-1 MPa.

[0089] In the present invention, preferably, the homopolymerization reaction time is 5 min-5 h, for example, it can be 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h and any range consisting of any two values ​​therein, more preferably 1-3 h.

[0090] In the present invention, preferably, the second solvent may be a solvent that has been purified to be anhydrous and oxygen-free.

[0091] In the present invention, preferably, the contacting may be performed under anhydrous and / or oxygen-free conditions.

[0092] According to some embodiments of the present invention, the method for preparing branched polyethylene includes: homopolymerization of ethylene monomer in the presence of a catalyst and a second solvent; wherein the catalyst contains the metal complex containing a pyridine ring as described in the first aspect of the present invention or the third aspect of the present invention; the second solvent is an inert solvent; the catalyst further contains a co-catalyst; the molar ratio of the metal complex to the co-catalyst is 1:(0.1-5000); the co-catalyst is selected from at least one of methylaluminoxane (MAO), modified methylaluminoxane (MMAO), trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, diethylaluminum chloride, and ethylaluminum dichloride; the conditions for the homopolymerization include: the temperature of the homopolymerization is 10-100°C; the homopolymerization is carried out under a protective atmosphere; the pressure of the homopolymerization is 0.1-1MPa; and the time of the homopolymerization is 1-3h.

[0093] The fifth aspect of the present invention provides a branched polyethylene, wherein in the branched structure of the branched polyethylene, the long branches with carbon atoms of four or more account for 17-55 mol% of the branch ratio;

[0094] Alternatively, the branched polyethylene is prepared by the method described in the fourth aspect of the present invention.

[0095] In the present invention, the branched polyethylene having the above characteristics, when used as a lubricating oil viscosity index improver, has good viscosity increasing ability and shear resistance, can effectively increase the viscosity index (VI) of the base oil, and can improve the viscosity-temperature property of the lubricating oil.

[0096] In the present invention, the proportion of the carbon four or more long branches to the branch ratio can be 17mol%, 18mol%, 19mol%, 20mol%, 21mol%, 22mol%, 23mol%, 24mol%, 25mol%, 26mol%, 27mol%, 28mol%, 29mol%, 30mol%, 31mol%, 32mol%, 33mol%, 34mol%, 35mol%, 36mol%, 37mol%, 38mol%, 39mol%, 40mol%, 45mol%, 50mol% and any value within the range of any two of the above values, preferably 17-40mol%, more preferably 18-33mol%, and further preferably 22-27mol%.

[0097] In the present invention, preferably, the number average molecular weight of the branched polyethylene is 10,000-150,000, for example, 10,000, 15,000, 18,000, 20,000, 24,000, 28,000, 30,000, 32,000, 34,000, 35,000, 38,000, 40,000, 42,000, 43,000, 45,000, 46,000, 47,000, 48,000, 49,000, 50,000, 51,000, 52,000, 53,000, 54,000, 55,000, 56,000, 57,000, 58,000, 59,000, 60,000, 61,000, 62,000, 63,000, 64,000, 65,000, 66,000, 67,000, 68,000, 69,000, 70,000, 71,000, 72,000, 73,000, 74,000, 75,000, 76,000, 77,000, 78,000, 79,000, 80,000 The present invention relates to an aqueous solution of at least one iodine number, wherein the aqueous solution has a molecular weight of 500 μm, and the aqueous solution has a molecular weight of 100 μm. The aqueous solution of at least one iodine number, wherein the aqueous solution has a molecular weight of 500 μm, and the aqueous solution has a molecular weight of 100 μm.

[0098] In the present invention, preferably, the molecular weight distribution index of the branched polyethylene is 0.5-4, for example, it can be 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, and any value within the range of any two of the above values, more preferably 2-3.

[0099] In the present invention, preferably, the degree of branching of the branched polyethylene is 50-180, for example, it can be 50, 60, 70, 80, 90, 100, 110, 120, 140, 160, 180, and any value within the range of any two of the above values, more preferably 70-160.

[0100] In the present invention, preferably, in the branched structure of the branched polyethylene, methyl branches account for 30-80 mol% of the branch content, for example, it can be 30 mol%, 35 mol%, 40 mol%, 45 mol%, 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, and any value within the range of any two of the above values, more preferably 40-70 mol%, and further preferably 45-70 mol%.

[0101] The inventors of the present invention have found in their research that if the content of methyl branches in branched polyethylene increases, the thickening ability of the branched polyethylene when used as a lubricating oil viscosity index improver will decrease; unlike ethylene-propylene copolymer viscosity index improvers, when the proportion of long branches with carbon atoms of four or more in the branched polyethylene increases, the thickening ability of the branched polyethylene will not decrease significantly, and the solubility in the lubricating oil will increase.

[0102] According to some preferred embodiments of the present invention, in the branched structure of the branched polyethylene, the long branches with carbon number of four or more account for 17-40 mol% of the branch ratio; the number average molecular weight of the branched polyethylene is 10,000-150,000; the molecular weight distribution index of the branched polyethylene is 0.5-4; the degree of branching of the branched polyethylene is 50-180; in the branched structure of the branched polyethylene, the methyl branches account for 30-80 mol% of the branch content. The branched polyethylene with the above characteristics, when used as a lubricating oil viscosity index improver, has better viscosity increasing ability and shear resistance, can further improve the viscosity index (VI) of the base oil, improve the viscosity-temperature property of the lubricating oil, and has better solubility in the lubricating oil.

[0103] According to some particularly preferred embodiments of the present invention, in the branched structure of the branched polyethylene, the long branches with carbon number of four or more account for 18-33 mol% of the branch ratio; the number average molecular weight of the branched polyethylene is 30,000-150,000; the molecular weight distribution index of the branched polyethylene is 2-3; the degree of branching of the branched polyethylene is 70-160; in the branched structure of the branched polyethylene, the methyl branches account for 40-70 mol% of the branch content. When the branched polyethylene with the above characteristics is used as a lubricating oil viscosity index improver, the viscosity increasing ability and shear resistance are further improved, the solubility in the lubricating oil is further increased; the viscosity index (VI) of the lubricating oil is further increased, and the viscosity-temperature property is further improved.

[0104] The sixth aspect of the present invention provides use of the branched polyethylene described in the fifth aspect of the present invention in a lubricating oil viscosity index improver.

[0105] In the present invention, the method of using the branched polyethylene of the present invention as a lubricating oil viscosity index improver is not particularly limited, and can be a conventional method in the art, for example, it can be: mixing the components including the branched polyethylene of the present invention with the base oil of the lubricating oil. The above-mentioned mixing temperature and time can be adjusted according to the specific mixing conditions, generally 50-150°C. The mixing is also not particularly limited, and can be a conventional mixing method in the art, such as stirring mixing, and the stirring time is not particularly limited, for example, it can be 2-5 hours.

[0106] The base oil of the lubricating oil may be a conventional base oil in the art, usually one or more of the base oils of Group I, II, III, IV and V in the American Petroleum Institute API classification, such as Group I 150SN, Group II 150N, 100N, etc.

[0107] When the branched polyethylene is used as a lubricating oil viscosity index improver, the amount added to the lubricating oil is not particularly limited, and can be added in a conventional manner, for example, according to the viscosity of the lubricating oil and the need to adjust the amount, which can be 0.01-10wt% of the lubricating oil, for example, 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.1wt%, 0.2wt%, 0.3wt% , 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 1.2wt%, 1.5wt%, 1.6wt%, 1.8wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, and any value within the range composed of any two of the above values, in order to take into account both the addition effect and the cost, it is preferably 0.5-5wt%, and more preferably 0.5-2wt%.

[0108] The seventh aspect of the present invention provides a lubricating oil, wherein the lubricating oil comprises the branched polyethylene described in the fifth aspect of the present invention.

[0109] In the present invention, the content of the branched polyethylene in the lubricating oil is not particularly limited, and can be 0.01-10wt% of the lubricating oil, for example, it can be 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 1.2wt%, 1.5wt%, 1.6wt%, 1.8wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, and any value within the range of any two of the above values. In order to take into account both the addition effect and the cost, it is preferably 0.5-5wt%, and more preferably 0.5-2wt%.

[0110] The present invention will be described in detail below through examples.

[0111] In the following examples, unless otherwise specified, all solvents, raw materials for synthesizing ligands, acids, bases, etc. are commercially available.

[0112] All air-sensitive and moisture-sensitive operations or steps were performed in high-purity N 2 or Ar using standard Schlenk techniques or with a high-capacity recirculator (<1 ppm O 2 ) in a Vigor glove box.

[0113] All glassware was dried in a vacuum oven at 110 °C for at least 48 h.

[0114] Ethylene was polymer grade ethylene purified by an ethylene purification system (developed by Dalian Institute of Chemical Physics, Chinese Academy of Sciences).

[0115] All solvents used have been purified to be anhydrous and oxygen-free. The hydrocarbon solvents used (such as toluene, n-hexane) are distilled from sodium / benzophenone and then vacuum transferred to sodium / potassium alloy for more rigorous dehydration and deoxygenation.

[0116] (1) Source of raw materials

[0117] The 300-400 mesh silica gel used for silica gel column chromatography was purchased from Yantai Jiangyou Development Co., Ltd.;

[0118] Thin layer chromatography plates (TLC plates) were purchased from Yantai Jiangyou Development Co., Ltd.;

[0119] (2) Analysis methods

[0120] The NMR spectra were measured using a JEOL 600 MHz NMR spectrometer (purchased from JEOL Ltd.) using the internal solvent resonance as a reference. 1 Chemical shifts for H spectra are reported relative to tetramethylsilane (TMS); the deuterated reagent is deuterated chloroform (Chloroform-d).

[0121] Elemental analysis was performed using an Elementar vario MicroCube instrument (purchased from Germany).

[0122] (I) Preparation of ligands

[0123] Preparation Example 1

[0124] This preparation example is used to illustrate the preparation of ligand L1:

[0125] Step (1):

[0126] Reaction equation:

[0127]

[0128] Super dry tetrahydrofuran (100 mL) was added to a 200 mL schlenk bottle. 6-methyl-2-pyridine carboxaldehyde (6.057 g, 50 mmol) was added under ice-water bath conditions. After it was completely dissolved, cyclopentyl magnesium chloride (50 mL, 50 mmol, 1 mol / L tetrahydrofuran solution) was slowly added dropwise. After the addition was complete, the ice-water bath was removed and the reaction was restored to room temperature. The reaction was tracked by NMR. After 5 h of reaction, ammonium chloride solution was added to quench the reaction. The reaction was extracted with ethyl acetate, dried over anhydrous sodium sulfate, concentrated, and chromatographed on a silica gel column (column moistened with triethylamine, ethyl acetate / petroleum ether = 1 / 20) to obtain cyclopentyl (6-methylpyridin-2-yl) methanol. The product was a light yellow solid. The yield was 68%. The product was analyzed and the results were as follows:

[0129] 1 H NMR(500MHz,Chloroform-d)δ7.57–7.51(m,1H),7.32(dt,J=8.1,0.9Hz,1H),7.07 (dt,J=7.5,0.9Hz,1H),4.73–4.67(m,1H),4.04(d,J=5.1Hz,1H),2.52(d,J=0.7Hz, 3H),2.33(dp,J=6.8,5.5Hz,1H),1.81–1.72(m,1H),1.76–1.68(m,1H),1.67(dddd, J=10.6,5.0,2.7,1.5Hz,3H),1.64(ddd,J=5.6,4.3,2.0Hz,1H),1.64–1.55(m,1H).

[0130] Step (2):

[0131] Reaction equation:

[0132]

[0133] Under argon atmosphere, the product obtained in step (1) (7.6508 g, 40 mmol), 150 mL of ultra-dry dichloromethane, MnO 2 (Pre-activated, dried at 110°C for one day) (35 g, 400 mmol), argon protection throughout the process, TLC plate tracking, reaction for 3 hours, the reaction system was passed through diatomaceous earth, rotary evaporation and vacuum pump to obtain 3.5 g of yellow solid, cyclopentyl (6-methylpyridin-2-yl) methanone, with a yield of 46%. The product was analyzed and the results were as follows:

[0134] 1H NMR(500MHz,Chloroform-d)δ7.73(dd,J=7.8,1.2Hz,1H),7.68–7.62(m,1H),7.25–7.20( m,1H),2.76(p,J=5.5Hz,1H),2.49(d,J=0.7Hz,3H),2.09–1.90(m,4H),1.75–1.59(m,4H).

[0135] Step (3):

[0136] Reaction equation:

[0137]

[0138] (3-1) In an argon atmosphere, 50 mL of dichloromethane, 2,6-diisopropylaniline (2.4 mL, 12.9 mmol), triethylamine (5.4 mL, 38.7 mmol) and TiCl were added to a 100 mL dry reaction bottle. 4 (2.8 mL, 25.8 mmol) was reacted at room temperature for half an hour, and the reaction system turned dark green;

[0139] (3-2) The product obtained in step (2) (2.4410 g, 12.9 mmol) was added to the system. The raw material disappeared (7 h) by TLC (PE:EA=5:1), and the reaction was completed. The reaction solution was added to 100 mL of saturated sodium bicarbonate solution to quench the reaction, filtered through diatomaceous earth, separated, extracted with dichloromethane three times, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and chromatographed on a silica gel column (ethyl acetate / petroleum ether=1 / 100-1 / 50, the silica gel was soaked in pure triethylamine overnight, and flushed to neutrality with petroleum ether when loading the column) to obtain 1.89 g of yellow solid L1, with a yield of 42%. The product was analyzed, and the results were as follows:

[0140] 1 H NMR(500MHz,Chloroform-d)δ7.58(dd,J=7.3,1.3Hz,1H),7.51(t,J=7.3Hz,1H),7.30–7.16(m,4H),3.27(p,J=5. 1Hz,1H),3.18–3.07(m,2H),2.51(d,J=0.7Hz,3H),1.99–1.83(m,4H),1.75–1.64(m,4H),1.27(d,J=6.2Hz,12H).

[0141] Preparation Example 2-18

[0142] The method for preparing ligands L2-L18 is the same as that of Preparation Example 1, except that the raw materials involved in step (1) and step (3-1) are different. The raw materials required in step (1) and step (3) of Preparation Example 2-18, the final yield, the structure of ligands L2-L18 and their structural characterization are shown in Table 1.

[0143] Table 1

[0144]

[0145]

[0146]

[0147]

[0148]

[0149] (II) Preparation of metal complexes containing pyridine rings

[0150] Example 1

[0151] This example is used to illustrate the preparation of the metal complex C1 containing a pyridine ring.

[0152] Take 1mmol NiBr 2 After mixing (DME) and 1.05mmol of L1, the reaction system was replaced with nitrogen three times, 20mL of anhydrous dichloromethane was added and stirred for 12h. The reaction solution was filtered, the filtrate was desolventized under reduced pressure, and a mixed solvent of dichloromethane / n-hexane (2mL / 20mL) was added to wash the solid three times. After filtering, the remaining solid was dried under vacuum. The product was obtained as a red solid with a yield of 87%. Elemental analysis results Anal.Calcd.For C 24 H 32 Br 2 N 2 Ni: C, 50.84; H, 5.69; N, 4.94; Found: C, 50.74; H, 5.39; N, 4.84.

[0153] Example 2-18

[0154] The pyridine ring-containing metal complex C2-18 was prepared according to the method of Example 1, except that ligands L2-L18 were used respectively. The structure and elemental analysis results of the obtained pyridine ring-containing metal complex C2-18 are shown in Table 2.

[0155] Table 2

[0156]

[0157]

[0158]

[0159]

[0160] Comparative Example 1

[0161] Ligand L19 was prepared according to the method of Preparation Example 1, and the structure is as follows:

[0162]

[0163] According to the method of Example 1, the difference is that the ligand L19 is used to prepare the metal complex C19 containing a pyridine ring, and the structure is as follows:

[0164]

[0165] Comparative Example 2

[0166] Ligand L20 was prepared according to the method of Preparation Example 1, and the structure is as follows:

[0167]

[0168] According to the method of Example 1, the difference is that the ligand L20 is used to prepare the metal complex C20 containing a pyridine ring, and the structure is as follows:

[0169]

[0170] Comparative Example 3

[0171] Ligand L21 was prepared according to the method of Preparation Example 1, and its structure is as follows:

[0172]

[0173] According to the method of Example 1, the difference is that the ligand L21 is used to prepare the metal complex C21 containing a pyridine ring, and the structure is as follows:

[0174]

[0175] (III) Preparation of branched polyethylene

[0176] Used to illustrate the preparation of branched polyethylene and its preparation method using the pyridine ring-containing metal complexes C1-C18 obtained in Examples 1-18.

[0177] The number average molecular weight (Mn) and molecular weight distribution (PDI) of branched polyethylene were measured by CFC multifunctional polyolefin analysis characterization instrument (purchased from Polymer Char, Spain) at 150°C (polystyrene calibration, 1,2-dichlorobenzene as solvent, 150°C, solvent flow rate of 1.0 mL / min).

[0178] The degree of branching was measured by JEOL 600 MHz NMR instrument at 120 °C in deuterated tetrachloroethane.

[0179] The proportion of long branches with carbon atoms greater than four to four was measured by JEOL 600 MHz nuclear magnetic resonance instrument at 120°C in deuterated tetrachloroethane.

[0180] Polyethylene Preparation Example 1

[0181] A 1L stainless steel polymerization kettle equipped with mechanical stirring was vacuum dried continuously at 130°C for 5 hours, during which the atmosphere was replaced with nitrogen 3 times. 500mL toluene, 5.8mg (10μmol) of the metal complex C1 containing a pyridine ring, and 6.5ml of methylaluminoxane (MAO) (derived from a toluene solution of MAO with a concentration of 1.5mol / L) were added to the replaced polymerization kettle; ethylene gas was introduced, and the mixture was stirred at 40°C and 0.5Mpa ethylene pressure for 2 hours. A polyethylene product was obtained after treatment with an ethanol solution containing 5wt% hydrochloric acid.

[0182] The obtained branched polyethylene M n =91,000, PDI = 2.31; degree of branching: 119; methyl branch content 50.1 mol%, carbon four or more long branches account for 25 mol% of the branch ratio.

[0183] Polyethylene Preparation Example 2

[0184] The method in Polyethylene Preparation Example 1 was followed, except that the reaction was carried out at 20°C and 0.5 MPa ethylene pressure for 2 hours.

[0185] The obtained branched polyethylene has Mn=124,000, PDI=2.6, and a branching degree of 108; the methyl branch content is 56.1 mol%, and the long branches with carbon atoms of four or more account for 22 mol% of the branches.

[0186] Polyethylene Preparation Example 3

[0187] The method in Polyethylene Preparation Example 1 was followed, except that the reaction was carried out at 60°C and 0.5 MPa ethylene pressure for 2 hours.

[0188] The obtained branched polyethylene has Mn=73,000, PDI=2.53, and a branching degree of 126; the methyl branch content is 48.9 mol%, and the long branches with carbon atoms of four or more account for 26 mol% of the branches.

[0189] Polyethylene Preparation Example 4

[0190] The method in Polyethylene Preparation Example 1 was followed, except that the reaction was carried out at 100°C and 0.5 MPa ethylene pressure for 2 hours.

[0191] The obtained branched polyethylene has Mn=43,000, PDI=3.0, and a branching degree of 131; the methyl branch content is 43.1 mol%, and the long branches with carbon atoms of four or more account for 29 mol% of the branches.

[0192] Polyethylene Preparation Example 5

[0193] The method in Polyethylene Preparation Example 1 was followed, except that the solvent was n-hexane.

[0194] The obtained branched polyethylene has Mn=103,000, PDI=2.71, and a branching degree of 153; the methyl branch content is 46.3 mol%, and the long branches with carbon atoms of four or more account for 27 mol% of the branches.

[0195] Polyethylene Preparation Example 6

[0196] The method of Polyethylene Preparation Example 1 is followed, except that the metal complex containing a pyridine ring is C2.

[0197] The obtained branched polyethylene has Mn=97,000, PDI=2.42, and a branching degree of 116; the methyl branch content is 52.3 mol%, and the long branches with carbon atoms of four or more account for 24 mol% of the branches.

[0198] Polyethylene Preparation Example 7

[0199] The method of Polyethylene Preparation Example 1 is followed, except that the metal complex containing a pyridine ring is C3.

[0200] The obtained branched polyethylene has Mn=106,000, PDI=2.36, and a branching degree of 113; the methyl branch content is 53.3 mol%, and the long branches with carbon atoms of four or more account for 24 mol% of the branches.

[0201] Polyethylene Preparation Example 8

[0202] The method of Polyethylene Preparation Example 1 is followed, except that the metal complex containing a pyridine ring is C5.

[0203] The obtained branched polyethylene has Mn=87,000, PDI=2.43, and a branching degree of 124; the methyl branch content is 54.6 mol%, and the long branches with carbon atoms of four or more account for 25 mol% of the branches.

[0204] Polyethylene Preparation Example 9

[0205] The method of Polyethylene Preparation Example 2 is followed, except that the metal complex containing a pyridine ring is C6.

[0206] The obtained branched polyethylene has Mn=108,000, PDI=2.52, and a branching degree of 122; the methyl branch content is 55.6 mol%, and the long branches with carbon atoms of four or more account for 21 mol% of the branches.

[0207] Polyethylene Preparation Example 10

[0208] The method in Polyethylene Preparation Example 2 was followed, except that the metal complex containing a pyridine ring was C8. The obtained branched polyethylene had Mn=57,000, PDI=2.21, and a branching degree of 137; the methyl branch content was 45.6 mol%, and the long branches above C4 accounted for 28 mol% of the branches.

[0209] Polyethylene Preparation Example 11

[0210] The method of Polyethylene Preparation Example 2 is followed, except that the metal complex containing a pyridine ring is C14.

[0211] The obtained branched polyethylene has Mn=72,000, PDI=2.34, and a branching degree of 76; the methyl branch content is 49.6 mol%, and the long branches with carbon atoms of four or more account for 27 mol% of the branches.

[0212] Polyethylene Preparation Example 12

[0213] The method of Polyethylene Preparation Example 2 is followed, except that the metal complex containing a pyridine ring is C15.

[0214] The obtained branched polyethylene has Mn=120,000, PDI=2.65, and a branching degree of 114; the methyl branch content is 53.2 mol%, and the long branches with carbon numbers greater than four account for 22 mol% of the branches.

[0215] Polyethylene Preparation Example 13

[0216] The method of Polyethylene Preparation Example 2 is followed, except that the metal complex containing a pyridine ring is C16.

[0217] The obtained branched polyethylene has Mn=83,000, PDI=2.91, and a branching degree of 127; the methyl branch content is 53.2 mol%, and the long branches with carbon numbers greater than four account for 26 mol% of the branches.

[0218] Polyethylene Preparation Example 14

[0219] The method of Polyethylene Preparation Example 2 is followed, except that the metal complex containing a pyridine ring is C17.

[0220] The obtained branched polyethylene has Mn=135,000, PDI=2.71, and a branching degree of 111; the methyl branch content is 56.7 mol%, and the long branches with carbon numbers greater than four account for 21 mol% of the branches.

[0221] Polyethylene Preparation Example 15

[0222] The method of Polyethylene Preparation Example 2 is followed, except that the metal complex containing a pyridine ring is C4.

[0223] The obtained branched polyethylene has Mn=92,000, PDI=1.89, and a branching degree of 84; the methyl branch content is 49 mol%, and the long branches with carbon numbers greater than four account for 27 mol% of the branches.

[0224] Polyethylene Preparation Example 16

[0225] The method of Polyethylene Preparation Example 2 is followed, except that the metal complex containing a pyridine ring is C9.

[0226] The obtained branched polyethylene has Mn=101,000, PDI=2.12, and a branching degree of 114; the methyl branch content is 51 mol%, and the long branches with carbon numbers above four account for 23 mol% of the branches.

[0227] Polyethylene Preparation Example 17

[0228] The method of Polyethylene Preparation Example 2 is followed, except that the metal complex containing a pyridine ring is C10.

[0229] The obtained branched polyethylene has Mn=83,000, PDI=2.5, and a branching degree of 76; the methyl branch content is 45.5 mol%, and the long branches with carbon atoms of four or more account for 18 mol% of the branches.

[0230] Polyethylene Preparation Example 18

[0231] The method of Polyethylene Preparation Example 2 is followed, except that the metal complex containing a pyridine ring is C11.

[0232] The obtained branched polyethylene has Mn=130,000, PDI=1.5, and a branching degree of 131; the methyl branch content is 56 mol%, and the long branches with carbon numbers greater than four account for 26 mol% of the branches.

[0233] Polyethylene Preparation Comparative Example 1

[0234] The method of Polyethylene Preparation Example 1 is followed, except that the metal complex containing a pyridine ring is C19.

[0235] The obtained branched polyethylene has Mn=21,000, PDI=2.5, and a branching degree of 62; the methyl branch content is 83 mol%, and the long branches with carbon numbers above four account for 8 mol% of the branches.

[0236] Polyethylene Preparation Comparative Example 2

[0237] The method of Polyethylene Preparation Example 1 is followed, except that the metal complex containing a pyridine ring is C20.

[0238] The obtained branched polyethylene has Mn=32,000, PDI=2.3, and a branching degree of 88; the methyl branch content is 76 mol%, and the long branches with carbon numbers above four account for 14 mol% of the branches.

[0239] Polyethylene Preparation Comparative Example 3

[0240] The method of Polyethylene Preparation Example 1 is followed, except that the metal complex containing a pyridine ring is C21.

[0241] The obtained branched polyethylene has Mn=52,000, PDI=3.1, and a branching degree of 92; the methyl branch content is 71 mol%, and the long branches with carbon numbers greater than four account for 16 mol% of the branches.

[0242] Polyethylene Preparation Comparative Example 4

[0243] Commercially available branched polyethylene was used, with Mn=76,000, PDI=2.6, degree of branching: 135, methyl branch content of 100 mol%, and no carbon four or more long chain branches.

[0244] Application Examples

[0245] The branched polyethylene provided in the polyethylene preparation examples and the polyethylene preparation comparative examples is used to illustrate the viscosity performance of the branched polyethylene used as a viscosity index improver.

[0246] Kinematic viscosity at 40°C (KV(40°C)) is measured in accordance with GB / T 265-1988;

[0247] Kinematic viscosity at 100°C (KV(100°C)) is measured in accordance with GB / T 265-1988;

[0248] The viscosity index (VI) is calculated / determined according to GB / T 1995-1998. The higher the viscosity index, the less the oil is affected by temperature and the better its viscosity-temperature performance.

[0249] The 100°C shear stability index (SSI) is determined according to the method in Appendix C of SH / T 0622-2007. The lower the value of the shear stability index, the smaller the viscosity change of the lubricating oil after shearing, the better the shear stability of the oil, and the better the shear resistance of the viscosity index improver.

[0250] The base oil used in the test is 150SN base oil (purchased from Formosa Plastics Corporation), and its basic parameters are: KV (40°C) = 30.57 mm 2 / s, KV(100℃)=5.540mm 2 / s, VI=120.

[0251] Application Example 1

[0252] The branched polyethylene prepared in Branched Polyethylene Preparation Example 1 was added to 150SN base oil in an amount of 1 wt %, and stirred at 80° C. for 3 hours to dissolve. The lubricating oil KV (40° C.) = 66.78 mm 2 / s, KV(100℃)=11.79mm 2 / s, VI=172, SSI=28.

[0253] Application Example 2

[0254] The branched polyethylene prepared in Branched Polyethylene Preparation Example 2 was added to 150SN base oil in an amount of 1 wt%, and stirred at 80°C for 3 hours to dissolve. The lubricating oil KV (40°C) = 41.42 mm 2 / s, KV(100℃)=7.94mm 2 / s, VI=167, SSI=32.

[0255] Application Example 3

[0256] The branched polyethylene prepared in Branched Polyethylene Preparation Example 3 was added to 150SN base oil in an amount of 1 wt%, and stirred at 80°C for 3 hours to dissolve. The lubricating oil KV (40°C) = 63.93 mm 2 / s, KV(100℃)=10.05mm 2 / s, VI=143, SSI=27.

[0257] Application Example 4

[0258] The branched polyethylene prepared in Branched Polyethylene Preparation Example 5 was added to 150SN base oil in an amount of 1 wt%, and stirred at 80°C for 3 hours to dissolve. The lubricating oil KV (40°C) = 280.6 mm 2 / s, KV(100℃)=35.15mm 2 / s, VI=173, SSI=35.

[0259] Application Example 5

[0260] The branched polyethylene prepared in Branched Polyethylene Preparation Example 6 was added to 150SN base oil in an amount of 1 wt%, and stirred at 80°C for 3 hours to dissolve. The lubricating oil KV (40°C) = 150.7 mm 2 / s, KV(100℃)=20.75mm 2 / s, VI=161, SSI=30.

[0261] Application Example 6

[0262] The branched polyethylene prepared in Branched Polyethylene Preparation Example 13 was added to 150SN base oil in an amount of 1 wt %, and stirred at 80° C. for 3 hours to dissolve. The lubricating oil KV (40° C.) = 363.3 mm 2 / s, KV(100℃)=44.05mm 2 / s, VI=178, SSI=37.

[0263] Application Example 7

[0264] The branched polyethylene prepared in Branched Polyethylene Preparation Example 4 was added to 150SN base oil in an amount of 1 wt%, and stirred at 80°C for 3 hours to dissolve. The lubricating oil KV (40°C) = 48.83 mm 2 / s, KV(100℃)=8.03mm 2 / s, VI=135, SSI=29.

[0265] Application Example 8

[0266] The branched polyethylene prepared in Branched Polyethylene Preparation Example 10 was added to 150SN base oil in an amount of 1 wt %, and stirred at 80° C. for 3 hours to dissolve. The lubricating oil KV (40° C.) = 40.42 mm 2 / s, KV(100℃)=7.12mm 2 / s, VI=139, SSI=30.

[0267] Application Example 9

[0268] The branched polyethylene prepared in Branched Polyethylene Preparation Example 11 was added to 150SN base oil in an amount of 1 wt %, and stirred at 80° C. for 3 hours to dissolve. The lubricating oil KV (40° C.) = 67.64 mm 2 / s, KV(100℃)=11.21mm 2 / s, VI=159, SSI=33.

[0269] Application Example 10

[0270] The branched polyethylene prepared in Branched Polyethylene Preparation Example 14 was added to 150SN base oil in an amount of 1 wt %, and stirred at 80° C. for 3 hours to dissolve. The lubricating oil KV (40° C.) = 70.25 mm 2 / s, KV(100℃)=12.14mm 2 / s, VI=171, SSI=36.

[0271] Application Example 11

[0272] The branched polyethylene prepared in Branched Polyethylene Preparation Example 15 was added to 150SN base oil in an amount of 1 wt %, and stirred at 80°C for 3 hours to dissolve. The lubricating oil KV (40°C) = 63.63 mm 2 / s, KV(100℃)=10.11mm 2 / s, VI=145, SSI=28.

[0273] Application Example 12

[0274] The branched polyethylene prepared in Branched Polyethylene Preparation Example 16 was added to 150SN base oil in an amount of 1 wt %, and stirred at 80° C. for 3 hours to dissolve. The lubricating oil KV (40° C.) = 64.52 mm 2 / s, KV(100℃)=10.62mm 2 / s, VI=155, SSI=30.

[0275] Application Example 13

[0276] The branched polyethylene prepared in Branched Polyethylene Preparation Example 17 was added to 150SN base oil in an amount of 1 wt %, and stirred at 80°C for 3 hours to dissolve. The lubricating oil KV (40°C) = 61.53 mm 2 / s, KV(100℃)=9.82mm 2 / s, VI=144, SSI=27.

[0277] Application Example 14

[0278] The branched polyethylene prepared in Branched Polyethylene Preparation Example 18 was added to 150SN base oil in an amount of 1 wt %, and stirred at 80° C. for 3 hours to dissolve. The lubricating oil KV (40° C.) = 68.91 mm 2 / s, KV(100℃)=11.82mm 2 / s, VI=168, SSI=32.

[0279] Application Comparative Example 1

[0280] Preparation of branched polyethylene Comparative Example 1 The branched polyethylene prepared was added with 150SN base oil in an amount of 1 wt%, and stirred at 80°C for 3 hours to dissolve. The lubricating oil KV (40°C) = 40.56 mm 2 / s, KV(100℃)=6.89mm 2 / s, VI=128, SSI=30.

[0281] Application Comparative Example 2

[0282] The branched polyethylene prepared in Comparative Example 2 was added with 150SN base oil in an amount of 1 wt%, and stirred at 80°C for 3 hours to dissolve. The lubricating oil KV (40°C) = 50.65 mm 2 / s, KV(100℃)=8.03mm 2 / s, VI=129, SSI=31.

[0283] Application Comparative Example 3

[0284] Preparation of branched polyethylene Comparative Example 3 The prepared branched polyethylene was added with 150SN base oil in an amount of 1 wt%, and stirred at 80°C for 3 hours to dissolve. The lubricating oil KV (40°C) = 52.5 mm 2 / s, KV(100℃)=8.56mm 2 / s, VI=139, SSI=34.

[0285] Application Comparative Example 4

[0286] The branched polyethylene prepared in Comparative Example 4 was added with 150SN base oil in an amount of 1 wt%, and stirred at 80°C for 3 hours to dissolve. The lubricating oil KV (40°C) = 65.8 mm 2 / s, KV(100℃)=10.1mm 2 / s, VI=139, SSI=34.

[0287] It can be seen from the results that, under the catalysis of the pyridine ring-containing metal complex described in Examples 1-18 of the present invention, ethylene monomer is homopolymerized to obtain branched polyethylene, and the number average molecular weight, degree of branching, content of methyl branches, and content of long branches with more than four carbon atoms can be controlled and combined over a wide range. As a lubricating oil viscosity index improver, it can be beneficial to improve the viscosity-temperature properties of the lubricating oil.

[0288] Compared with polyethylene preparation comparative examples 1-4, the branched polyethylene obtained in polyethylene preparation examples 2, 5, 11, 12, 14 and 18, when used as a lubricating oil viscosity index improver, can make the viscosity index (VI) of the lubricating oil be between 129 and 178, and the 100°C shear stability index (SSI) be between 32 and 37, indicating that the lubricating oil viscosity index improver has good shear resistance and good viscosity-temperature properties of the lubricating oil.

[0289] Compared with polyethylene preparation comparative examples 1-4 and polyethylene preparation examples 2, 5, 11, 12, 14 and 18, the branched polyethylene obtained in polyethylene preparation examples 1, 3, 6, 15-17, when used as a lubricating oil viscosity index improver, can make the viscosity index (VI) of the lubricating oil be between 143 and 172, and the 100°C shear stability index (SSI) be between 27 and 30, indicating that the lubricating oil viscosity index improver has better shear resistance and the viscosity-temperature performance of the lubricating oil is further improved.

[0290] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A metal complex containing a pyridine ring, It is characterized in that The metal complex has a structure shown in formula (1): Wherein, M is selected from nickel or palladium; X is selected from halogen, C1-C4 alkyl, C2-C6 alkenyl, Benzyl; R 1 Selected from C1-C8 alkyl, C1-C8 haloalkyl, C3-C8 cycloalkyl, C3-C8 halocycloalkyl, unsubstituted or substituted phenyl; R 2 Selected from C3-C8 cycloalkyl, C3-C8 halogenated cycloalkyl; R 3 Selected from C1-C5 alkyl, C3-C8 cycloalkyl, halogen, unsubstituted or substituted phenyl, C1-C5 alkoxy, C1-C5 silyl; R 4 Selected from C1-C5 alkyl, C3-C8 cycloalkyl, halogen, unsubstituted or substituted phenyl, C1-C5 alkoxy, C1-C5 silyl; R 5 Selected from hydrogen, C1-C5 alkyl, C3-C8 cycloalkyl, unsubstituted or substituted phenyl, halogen or C1-C5 alkoxy.

2. The metal complex according to claim 1, in, The R 1 Selected from C1-C8 alkyl, C3-C8 cycloalkyl, unsubstituted or substituted phenyl; Preferably, the R 1 Selected from C1-C5 alkyl, C3-C8 cycloalkyl or phenyl; Preferably, the R 2 Selected from C3-C6 cycloalkyl, C3-C6 halogenated cycloalkyl. Preferably, the R 3 Selected from C1-C5 alkyl, C3-C8 cycloalkyl, C1-C5 silyl, halogen or phenyl; Preferably, the R 4 Selected from C1-C5 alkyl, C3-C8 cycloalkyl, C1-C5 silyl, halogen or phenyl; Preferably, the R 5 is selected from hydrogen, halogen or C1-C3 alkoxy; Preferably, X is selected from fluorine, chlorine or bromine.

3. The metal complex according to claim 1 or 2, in, The R 1 is selected from methyl, ethyl, isopropyl, cyclohexyl or phenyl; Preferably, the R 2 is selected from cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl or 4-chlorocyclohexyl; Preferably, the R 3 is selected from isopropyl, cyclopropyl, cyclopentyl, cyclohexyl, trimethylsilyl, bromine or phenyl; Preferably, the R 4 is selected from methyl, isopropyl, cyclohexyl, trimethylsilyl, bromine or phenyl; Preferably, the R 5 is selected from hydrogen, bromine or methoxy.

4. A method for preparing a metal complex containing a pyridine ring, It is characterized in that The method comprises: making a ligand having a structure shown in formula (2) react with a metal compound MX 2 touch; Wherein, the ligand of the structure shown in formula (2) and the metal compound MX 2 In, R 1 , R 2 , R 3 , R 4 , R 5 , M and X are as defined in any one of claims 1-3.

5. The method according to claim 4, in, The contact temperature is 0-100°C, preferably 30-60°C; Preferably, the contact time is 5-48h, preferably 5-24h; and / or, the molar ratio of the ligand to the metal compound is (0.5-3):1, preferably (1-2):1; and / or, the contacting is performed in the presence of a first solvent; Preferably, the first solvent is an inert solvent; More preferably, the first solvent is selected from at least one of toluene, n-hexane, dichloromethane, 1,2-dichloroethane, and chlorobenzene.

6. A metal complex prepared by the method according to claim 4 or 5.

7. A method for preparing branched polyethylene, It is characterized in that The preparation method comprises: homopolymerizing ethylene monomer in the presence of a catalyst and a second solvent; Wherein, the catalyst contains the pyridine ring-containing metal complex according to any one of claims 1-3 and 6.

8. The method according to claim 7, in, The second solvent is an inert solvent; More preferably, the second solvent is selected from at least one of toluene, n-hexane, dichloromethane, 1,2-dichloroethane and chlorobenzene.

9. The method according to claim 7 or 8, in, The catalyst also contains a promoter; Preferably, the molar ratio of the metal complex to the co-catalyst is 1:(0.01-10000), preferably 1:(0.1-5000), more preferably 1:(1-1000); Preferably, the co-catalyst is selected from at least one of alkyl aluminum and organic boron; More preferably, the alkylaluminum is selected from at least one of methylaluminoxane, modified methylaluminoxane, trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, diethylaluminum chloride, and ethylaluminum dichloride; More preferably, the organoboron is selected from at least one of an organoboron compound of a trisubstituted ammonium salt, an organoboron compound containing a carbonium ion, and an organoboron compound containing a Lewis acid; Further preferably, the organic boron compound of the trisubstituted ammonium salt is selected from at least one of N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N-di(hexadecyl)aniline tetrakis(pentafluorophenyl)borate, N,N-dioctadecylaniline tetrakis(pentafluorophenyl)borate, triphenylcarbon tetrakis(pentafluorophenyl)borate and tris(pentafluorophenyl)borane.

10. The method according to claim 7 or 8, in, The conditions of the homopolymerization reaction include: The temperature of the homopolymerization reaction is 0°C-150°C, preferably 10-100°C; and / or, the homopolymerization reaction is carried out under a protective atmosphere; Preferably, the homopolymerization reaction pressure is 0.1-10 MPa, more preferably 0.1-1 MPa; Preferably, the homopolymerization reaction time is 5 min-5 h, more preferably 1-3 h.

11. A branched polyethylene, It is characterized in that In the branched structure of the branched polyethylene, the long branches with carbon atoms of four or more account for 17-55 mol% of the branch ratio; Alternatively, the branched polyethylene is prepared by the method described in any one of claims 7-10.

12. The branched polyethylene according to claim 11, in, The carbon four or more long chain branches account for 17-40 mol% of the branch ratio, preferably 18-33 mol%, and more preferably 18-27 mol%; Preferably, the number average molecular weight of the branched polyethylene is 10,000-150,000, preferably 30,000-150,000; Preferably, the molecular weight distribution index of the branched polyethylene is 0.5-4, preferably 2-3; Preferably, the branching degree of the branched polyethylene is 50-180, preferably 70-160; Preferably, in the branched structure of the branched polyethylene, methyl branches account for 30-80 mol %, more preferably 40-70 mol %, and further preferably 45-70 mol % of the branch content.

13. Use of the branched polyethylene according to claim 11 or 12 in a lubricating oil viscosity index improver.

14. A lubricating oil, It is characterized in that The lubricating oil comprises the branched polyethylene according to claim 11 or 12.

15. The lubricating oil according to claim 14, in, The content of the branched polyethylene in the lubricating oil is 0.01-10wt%, preferably 0.5-5wt%, more preferably 0.5-2wt%.

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