Isotactic cis-1,4-polyocimene and its preparation method and application

Abstract

The present invention discloses an isotactic cis-1,4-polyocimene, a preparation method, and an application thereof, belonging to the technical field of olefin polymer preparation. The present invention provides a novel isotactic cis-1,4-poly-β-ocimene, wherein the cis-1,4-structure content is ≥95% and the isotactic structure content is ≥90% (mm). Simultaneously, the present invention provides a rare earth catalyst system with high isotactic cis-1,4-structure selectivity for the polymerization of β-ocimene monomers, with the cis-1,4-selectivity reaching a maximum of greater than 99% and the isotactic selectivity reaching a maximum of greater than 99% (mm).

Description

Technical Field

[0001] The invention relates to isotactic cis-1,4-polyocimene and a preparation method and application thereof, belonging to the technical field of olefin polymer preparation. Background Art

[0002] Ocimene, a terpene derivative, is found in essential oils such as basil and lavender. Its molecule contains a conjugated diene structural unit, making it a promising bio-based monomer. However, to date, there have been few reports on the highly selective polymerization of ocimene. Li Xiaofang et al. from the Beijing Institute of Technology used a catalytic system of scandium cyclopentadienyl, lutetium, yttrium, and dysprosium to catalyze the homopolymerization of trans-1,4-β-ocimene, producing syndiotactic cis-1,4-polyβ-ocimene and isotactic trans-1,2-polyβ-ocimene (Macromol. Rapid Commun. 2016, 37, 987-992). Capacchione et al. in Italy reported using an [OSSO]-type titanium complex to catalyze the polymerization of ocimene, synthesizing isotactic 1,2-polyocimene at low temperatures and polyocimene with a predominantly trans-1,4-structure (>70%) at high temperatures (Polymer 2017, 131, 151-159). Recently, Valencia et al. studied the polymerization of ocimene using a Ziegler-Natta-type neodymium catalyst, producing polyocimene with a 1,4-structure content of approximately 79% (cis + trans) (RSCA Advances 2020, 10, 36539-36545). To date, there have been no reports of isotactic cis-1,4-polyβ-ocimene. Summary of the Invention

[0003] The purpose of the present invention is to provide an isotactic cis-1,4-polyocimene and a catalytic system, a preparation method and an application thereof.

[0004] The technical solution of the present invention:

[0005] One of the purposes of the present invention is to provide an isotactic cis-1,4-polyocimene having a molecular weight of 1,000 to 1,000,000 and a structural formula as follows:

[0006]

[0007] Wherein n is an integer.

[0008] It is further defined that the cis 1,4-structure content in the polymer is ≥95%, and the isotactic structure content is ≥90%.

[0009] A second object of the present invention is to provide a method for preparing isotactic cis-1,4-polyocimene. The method comprises the following steps: under the protection of an inert gas, using a rare earth complex, an organic boron compound and a co-catalyst as a catalytic system, in the presence of an organic solvent or in the absence of a solvent, catalyzing the polymerization reaction of ocimene monomers. After the reaction is completed, the product is precipitated and dried to obtain isotactic cis-1,4-polyocimene.

[0010] Further defined, the structural formula of the rare earth complex is as follows:

[0011]

[0012] Wherein, Q is the chelating ligand, X 1 and X 2 It is a monoanionic ligand, Ln is scandium, yttrium or a lanthanide rare earth element, L is tetrahydrofuran, pyridine or ethylene glycol dimethyl ether, and w is 0, 1 or 2.

[0013] It is further defined that Q is selected from one of Formulas III to VI;

[0014]

[0015] Where R 1 is methyl or tert-butyl; R 2 and R 4 is phenyl, p-methylphenyl, cyclohexyl, isopropyl or tert-butyl; R 3 is hydrogen or methyl; Ar 1 and Ar 2 is phenyl, p-methylphenyl, p-ethylphenyl, p-isopropylphenyl, p-tert-butylphenyl, m-methylphenyl, m-ethylphenyl, m-isopropylphenyl, mes-trimethylphenyl, 2,6-dimethylphenyl, 2,6-diethylphenyl, 2,6-diethyl-4-methylphenyl, mes-triethylphenyl, 2,6-diethyl-4-tert-butylphenyl, 2,6-diisopropylphenyl, 2,6-diisopropyl-4-methylphenyl, mes-triisopropylphenyl, 2,6-di-tert-butylphenyl, 2,6-di-tert-butyl-4-methylphenyl, 2,6-diphenylphenyl, 2,6-bis(trifluoromethyl)phenyl, 2-fluorophenyl, 3-(trifluoromethyl)phenyl, p-trifluoromethylphenyl or p-fluorophenyl.

[0016] Further limiting, R 1 For tert-butyl.

[0017] Further limiting, R 2 It is phenyl or p-methylphenyl.

[0018] Further limiting, R 3 It is a methyl group.

[0019] Further limiting, R 4It is phenyl or p-methylphenyl.

[0020] Further limiting, Ar 1 and Ar 2 is phenyl, p-methylphenyl, o-methylphenyl, o-ethylphenyl, o-isopropylphenyl, 2,6-dimethylphenyl, 2,6-diethylphenyl, 2,6-diisopropylphenyl or mesitylene.

[0021] Further limiting, Ar 1 and Ar 2 is 2,6-dimethylphenyl, mesitylene or 2,6-diethylphenyl.

[0022] In a further embodiment, Ln is scandium, yttrium, lanthanum, cerium, neodymium, gadolinium, dysprosium, holmium, erbium, thulium, ytterbium or lutetium.

[0023] In a further embodiment, Ln is lutetium, yttrium, holmium, erbium, lutetium, gadolinium, neodymium, or lanthanum.

[0024] In a further embodiment, Ln is yttrium, holmium, erbium, gadolinium, neodymium or lanthanum.

[0025] Further limiting, X 1 and X 2 is an alkyl group, an allyl group, a 2-methylallyl group, an aryl group, a benzyl group, a cycloalkyl group, a boryl group, a silylamino group, a silyl group, a halogen element, hydrogen, tetramethylaluminum or a 2-N'N-dimethylbenzyl group.

[0026] Further limiting, X 1 and X 2 is trimethylsilylene [CH2SiMe3] – 、Bis(trimethylsilyl)methine [CH(SiMe3)2] – 、Bis(trimethylsilyl)amino[N(SiMe3)2] – 、Bis(dimethylsilyl)amino[N(SiHMe2)2] – , 2-N'N-dimethylbenzyl, benzyl, p-methylbenzyl, [BH4] – or [AlMe4] – .

[0027] Further limiting, X 1 and X 2 2-N'N-dimethylbenzyl, benzyl, p-methylbenzyl, bis(dimethylsilyl)amino, [BH4] – or [AlMe4] – .

[0028] It is further defined that the rare earth complex is one of the following structural formulas:

[0029]

[0030]

[0031] It is further defined that the cocatalyst is an organic boron salt and / or an alkyl aluminum compound.

[0032] Furthermore, the organic boron salt is defined as containing [B(C6F5)4] - of organoboron reagents.

[0033] It is further defined that the organic boron salt is [NMeH(C 18 H 37 )2][B(C6F5)4], [Ph3C][B(C6F5)4], [PhNMe2H][B(C6F5)4] or more thereof can be mixed in any proportion.

[0034] Further limiting, the alkylaluminum compound is trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisopropylaluminum, triisobutylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum, triphenylaluminum, tri-p-tolylaluminum, tribenzylaluminum, ethyldibenzylaluminum, ethyldi-p-tolylaluminum, diethylbenzylaluminum, dimethylaluminum hydride, diethylaluminum hydride, di-n-propylaluminum hydride, di-n-butylaluminum hydride, diisopropylaluminum hydride, diisobutylaluminum hydride, dipentylaluminum hydride, dihexylaluminum hydride, dicyclohexylaluminum hydride, dioctylaluminum hydride, diphenylaluminum hydride , di-p-tolylaluminum hydride, dibenzylaluminum hydride, ethylbenzylaluminum hydride, ethyl-p-tolylaluminum hydride, dimethylaluminum chloride, diethylaluminum chloride, di-n-propylaluminum chloride, di-n-butylaluminum chloride, diisopropylaluminum chloride, diisobutylaluminum chloride, dipentylaluminum chloride, dihexylaluminum chloride, dicyclohexylaluminum chloride, dioctylaluminum chloride, diphenylaluminum chloride, di-p-tolylaluminum chloride, dibenzylaluminum chloride, ethylbenzylaluminum chloride, ethyl-p-tolylaluminum chloride, methylaluminoxane, ethylaluminoxane, n-propylaluminoxane, n-butylaluminoxane, one or more of which are mixed in any proportion.

[0035] Further defined, the structural formula of ocimene monomer is as follows:

[0036]

[0037] It is further defined that the organic solvent is one or more of saturated alkanes, aromatic hydrocarbons, halogenated aromatic hydrocarbons, and cycloalkanes mixed in any proportion.

[0038] It is further defined that the organic solvent is one or more of n-hexane, n-heptane, petroleum ether, cyclohexane, decahydronaphthalene, benzene, toluene, xylene, chlorobenzene, dichlorobenzene, and trichlorobenzene mixed in any proportion.

[0039] It is further defined that the organic solvent is one or more of n-hexane, n-heptane, petroleum ether, cyclohexane, decahydronaphthalene, toluene, and chlorobenzene mixed in any proportion.

[0040] It is further defined that the molar ratio of ocimene monomer to rare earth complex is (100-10000):1.

[0041] It is further defined that the molar ratio of ocimene monomer to rare earth complex is (500-5000):1.

[0042] It is further defined that the molar ratio of the rare earth complex, the organic boron compound and the co-catalyst is 1:(0-2):(0-500).

[0043] It is further defined that the molar ratio of the rare earth complex, the organic boron compound and the co-catalyst is 1:1:(0-200).

[0044] It is further defined that the polymerization reaction temperature is -30 to 100°C and the time is 0.1 to 48 hours.

[0045] It is further defined that the polymerization reaction temperature is 25 to 80° C. and the time is 0.5 to 8 hours.

[0046] It is further defined that after the polymerization reaction is completed, a hydrochloric acid ethanol solution with a volume concentration of 10% is added to terminate the polymerization reaction, and the reaction solution is poured into methanol for precipitation to obtain isotropic cis-1,4-polyocimene; the obtained polymer is then placed in a vacuum drying oven and dried to obtain isotropic cis-1,4-polyocimene of constant weight.

[0047] A third object of the present invention is to provide an application of isotactic cis-1,4-polyocimene, specifically as a rubber material for preparing rubber products.

[0048] The present invention has the following beneficial effects:

[0049] (1) The present invention provides a novel isotactic cis-1,4-poly-β-ocimene, wherein the cis-1,4-structure content is ≥95% and the isotactic structure content is ≥90% (mm).

[0050] (2) The present invention provides a rare earth catalyst system with high selectivity for isotactic cis-1,4 structure for the polymerization of β-ocimene monomer, wherein the cis-1,4-selectivity can reach a maximum of greater than 99%, and the isotactic selectivity can reach a maximum of greater than 99% (mm).

[0051] (3) The novel biomass elastomer provided by the present invention, isotactic cis-1,4-poly-β-ocimene, can be used as a rubber material for various rubber products. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1This is the H NMR spectrum of the isotactic cis-1,4-polyocimene obtained in Example 1;

[0053] Figure 2 This is the carbon NMR spectrum of the isotactic cis-1,4-polyocimene obtained in Example 1. DETAILED DESCRIPTION

[0054] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0055] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0056] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0057] Example 1

[0058] Under anhydrous and oxygen-free conditions, rare earth compound 1 (10.0 mg, 10 μmol), [Ph3C][B(C6F5)4] (9.2 mg, 10 μmol) and Al i 1 mL of a toluene solution of Bu3 (0.2 mL × 0.5 M) was added to a toluene solution (2 mL) containing ocimene monomer (0.68 g, 5.0 mmol) at 25°C. After 90 minutes of high-speed stirring, a small amount of ethanol solution was added to terminate the polymerization reaction. The reaction solution was then poured into methanol (100 ml) containing a small amount of hydrochloric acid and a stabilizer (BHT) for precipitation. The resulting polymer was placed in a vacuum drying oven at 40°C and dried for 48 hours to obtain a net weight of 0.5 g of polymer (yield 73%). The H NMR spectrum ( 1 H-NMR, such as Figure 1 ) and C NMR spectroscopy ( 13 C-NMR, such as Figure 2 ) analysis of the obtained ocimene homopolymer showed that its cis-1,4-selectivity was greater than 99% and its isoselectivity was greater than 99%. The number average molecular weight (M n ) is 105,000, and the molecular weight distribution (M w / M n ) is 1.16.

[0059] Examples 2 to 7

[0060] The differences between Examples 2 to 7 and Example 1 are detailed in Table 1 below. The remaining operating procedures and parameter settings are the same as those of Example 1.

[0061] Table 1

[0062]

[0063] Note: The amount of rare earth compound input is 10 μmol, and the organic boron salt is selected from [Ph3C][B(C6F5)4](A), [NMeH(C 18 H 37 )2][B(C6F5)4](B) or [PhNMe2H][B(C6F5)4](C).

[0064] As can be seen from the above table, the prepared polymer is isotactic cis-1,4-poly-β-ocimene, in which the cis-1,4-structure content is ≥95% and the isotactic structure content is ≥90% (mm).

[0065] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. An isotactic cis-1,4-polyocimene, characterized in that: The polymer has a number average molecular weight of 1,000 to 1,000,000 and a structural formula as follows: Wherein n is an integer.

2. The isotactic cis-1,4-polyocimene according to claim 1, characterized in that The cis 1,4-structure content in the polymer is ≥95%, and the isotactic structure content is ≥90%.

3. A method for preparing the isotactic cis-1,4-polyocimene according to claim 1, characterized in that: Under the protection of inert gas, a rare earth complex, an organic boron compound and a co-catalyst are used as a catalytic system, in the presence of an organic solvent or in the absence of a solvent, to catalyze the polymerization reaction of ocimene monomers. After the reaction is completed, the product is precipitated and dried to obtain isotactic cis-1,4-polyocimene. The structural formula of the rare earth complex is as follows: Wherein, Q is the chelating ligand, X 1 and X 2 is trimethylsilylene [CH2SiMe3] – 、Bis(trimethylsilyl)methine [CH(SiMe3)2] – 、Bis(trimethylsilyl)amino[N(SiMe3)2] – 、Bis(dimethylsilyl)amino[N(SiHMe2)2] – , 2-N'N-dimethylbenzyl, benzyl, p-methylbenzyl, [BH4] – or [AlMe4] – , Ln is scandium, yttrium or a lanthanide rare earth element, L is tetrahydrofuran, pyridine or ethylene glycol dimethyl ether, and w is 0, 1 or 2; Q is selected from one of formulas III to VI; Where R 1 is methyl or tert-butyl; R 2 and R 4 is phenyl, p-methylphenyl, cyclohexyl, isopropyl or tert-butyl; R 3 is hydrogen or methyl; Ar 1 and Ar 2 is phenyl, p-methylphenyl, p-ethylphenyl, p-isopropylphenyl, p-tert-butylphenyl, m-methylphenyl, m-ethylphenyl, m-isopropylphenyl, mes-trimethylphenyl, 2,6-dimethylphenyl, 2,6-diethylphenyl, 2,6-diethyl-4-methylphenyl, mes-triethylphenyl, 2,6-diethyl-4-tert-butylphenyl, 2,6-diisopropylphenyl, 2,6-diisopropyl-4-methylphenyl, mes-triisopropylphenyl, 2,6-di-tert-butylphenyl, 2,6-di-tert-butyl-4-methylphenyl, 2,6-diphenylphenyl, 2,6-bis(trifluoromethyl)phenyl, 2-fluorophenyl, 3-(trifluoromethyl)phenyl, p-trifluoromethylphenyl, or p-fluorophenyl; The cocatalyst is an organic boron salt and / or an alkyl aluminum compound.

4. The method for preparing isocitative cis-1,4-polyocimene according to claim 3, wherein: Organic boron salts contain [B(C6F5)4] - of organoboron reagents.

5. The method for preparing isocitative cis-1,4-polyocimene according to claim 3, wherein: The molar ratio of ocimene monomer to rare earth complex, organic boron compound and co-catalyst is (100-10000):1:(0-2):(0-500).

6. The method for preparing isotactic cis-1,4-polyocimene according to claim 3, wherein: The polymerization temperature is -30~100 o C, time is 0.1~48h.

7. A use of the isotactic cis-1,4-polyocimene according to claim 1, characterized in that: As a rubber material used in the preparation of rubber products.

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