High molecular weight poly linear alpha-olefin and preparation method thereof

Abstract

According to the method, an effective metal active center is provided by using a metallocene compound, internal impurities of a catalytic system are removed by using aluminum alkyl as a scavenging agent, and organic boride is used as an auxiliary agent of an anion catalytic environment, so that the high-molecular-weight poly (linear alpha-olefin) is prepared. The molecular weight distribution index (PDI) of the prepared poly linear alpha-olefin is 2.0-2.9, and the molecular weight range of the poly linear alpha-olefin is 17000-23000 g / mol. The reaction conditions of the preparation process are mild, and the operation is simple and convenient. And the prepared product has the advantages of narrow molecular weight distribution, high molecular weight, wide product applicability, wide application range and the like.

Description

Technical Field

[0001] The invention relates to the field of olefin polymerization, in particular to high molecular weight polylinear alpha-olefin and a preparation method thereof. Background Art

[0002] Linear α-olefins (LAO) generally refer to high-carbon straight-chain olefins of C4 and above, which can be used as basic raw materials for almost all chemical industries, such as polyolefin comonomers, surfactants, intermediates, lubricants, detergents, fine chemicals, plasticizers and oilfield chemicals (Polymer Chemistry, 2023, 14, 2542-2571). Most of the chemicals synthesized by it have good physical and chemical properties, such as wear resistance, high impact resistance, lubricity and chemical corrosion resistance, and some of them also play an important role in key areas such as national defense and military. Therefore, it is very important to develop this type of high-performance polymer material synthesis process (Acta Petrolei Sinica (Petroleum Processing Section), 2024, 40 (1), 266-276). Initially, researchers used Lewis acid catalysts to prepare low molecular weight polymer products (CN101054332A). Among them, Yang Xiaoming and other researchers (using cyclohexanone as initiator) were able to obtain polymerization products mainly composed of trimerization (58.0wt%) and tetramerization (27.0wt%) (Petroleum Refining and Chemical Engineering, 2012, 43(3), 56-59). In addition, Ding Hongsheng and others used BF3 catalyst to catalyze the polymerization of mixed α-olefins (water or alcohol as initiator), and were able to obtain higher selectivity for trimerization and tetramerization products than AlCl3 (Journal of Liaoning Petrochemical University, 2006, 26(1), 5-7).

[0003] In the above technical scheme, Lewis acid catalysts mainly composed of AlCl3 and BF3 show certain catalytic performance when catalyzing α-olefins, but they generate a large amount of wastewater during production, causing environmental damage, and the catalysts cannot be recycled, which also limits their use.

[0004] In addition, in order to improve the green value of the process, a variety of catalytic systems have also been introduced. For example, by using alkyl aluminum halide and alkane halide catalysts to catalyze the oligomerization of 1-decene and 1-dodecene and promote the polymerization of 1-decene, a low molecular weight polylinear α-olefin product with a kinematic viscosity of 128.4 cst at 40°C can be obtained (CN1505643A). Chinese patent No. CN1549852A discloses a single-site catalyst for the preparation of a variety of olefin oligomers, mainly through the catalytic polymerization of α-olefins to obtain up to 89wt% of dimer products, and after adjusting the scavenging dosage, the weight average molecular weight (M) of the polymer product is 2.54wt%.w ) can reach up to 9000g / mol. Chinese patent number CN117586441A discloses a method for preparing ultra-high molecular weight polymers, which uses Ti-Mg catalyst to catalyze the co-polymerization of hydrocarbon compounds and α-olefins at -30 to 30°C to obtain M w An ultra-high molecular weight polymerization product of not less than 3800000 g / mol; however, the applicability and application range of subsequent products of the excessively high molecular weight polymerization product are low, and the lower molecular weight polymerization product cannot meet the growing property requirements of social development.

[0005] Therefore, the development and preparation of w The method for producing high molecular weight polylinear α-olefin products (17000-23000 g / mol) has become a problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a high molecular weight polylinear α-olefin and a preparation method thereof, wherein the method uses a metallocene compound to provide an effective metal active center, uses an alkyl aluminum as a scavenger to remove internal impurities in the catalyst system, and uses an organic boron compound as an auxiliary agent for the anionic catalytic environment. The above makes the reaction conditions of the preparation process mild and the operation simple; and the prepared product has the advantages of narrow molecular weight distribution, high molecular weight, and wide product applicability and application range.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] According to one aspect of the present invention, there is provided a method for preparing a high molecular weight polylinear α-olefin, comprising the following steps:

[0009] After a certain proportion of polymerization monomers are mixed with a diluent solvent and alkyl aluminum, a metallocene catalyst and an organic boron compound are added in sequence to carry out a polymerization reaction. After the reaction is completed, a quencher is added to terminate the reaction, followed by standing and stratification, washing and rotary evaporation to finally obtain the high molecular weight polylinear α-olefin.

[0010] As a preferred embodiment, the polymerization monomer is 1-decene, the alkyl aluminum is industrial grade triisobutyl aluminum, the metallocene catalyst is rac-ethylene bis(1-indenyl) zirconium dichloride, and the organic boron compound is tri(pentafluorophenyl)borane and / or triphenylcarbon tetrakis(pentafluorophenyl)borate.

[0011] As a preferred embodiment, the molar ratio of the metallocene catalyst to 1-decene is 7×10 -5 ~12×10 -5 , preferably 8×10 -5 ~11×10-5 , more preferably 9×10 -5 ~10×10 -5 The molar ratio of the organic boride to the metallocene catalyst is 0.5 to 3.0, preferably 1.0 to 2.5, and more preferably 1.5 to 2.0; the molar ratio of the alkyl aluminum to the metallocene catalyst is 50 to 250, preferably 100 to 200, and more preferably 120 to 150.

[0012] As a preferred embodiment, the polymerization monomer is 1-decene, the dilution solvent is toluene, and the volume ratio of toluene to 1-decene is 0.2 to 1.0, preferably 0.4 to 0.6, and more preferably 0.5.

[0013] As a preferred embodiment, the control conditions of the polymerization reaction are:

[0014] The reaction temperature is 40 to 100°C, preferably 50 to 90°C, and more preferably 70 to 80°C;

[0015] The reaction time is 60 to 180 min, preferably 90 to 150 min, and more preferably 110 to 130 min.

[0016] As a preferred embodiment, the quenching agent is an acidified ethanol solution, the acidifying agent is concentrated hydrochloric acid, wherein the volume ratio of ethanol to concentrated hydrochloric acid is 8 to 14, preferably 10 to 12, and more preferably 11.

[0017] As a preferred embodiment, the washing process is to wash the delaminated materials with deionized water, wherein the volume ratio of deionized water to reactants is 0.5 to 2.0, preferably 0.8 to 1.5, and more preferably 1.0 to 1.2.

[0018] According to another aspect of the present invention, a high molecular weight polylinear α-olefin is further provided. The polylinear α-olefin prepared by the above method has a molecular weight distribution range of 17000 to 23000 g / mol and a molecular weight distribution index of 2.0 to 2.9.

[0019] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1. The present invention provides a high molecular weight polylinear α-olefin and a preparation method thereof. By using a metallocene catalyst and an organic boron compound, the prepared polylinear α-olefin has a molecular weight distribution index PDI of 2.0 to 2.9 and a molecular weight range of 17000 to 23000 g / mol, which indicates that the product has a relatively narrow molecular weight distribution and a regular molecular weight range, which helps to improve its processability and universality in downstream applications;

[0021] 2. The present invention provides a high molecular weight polylinear α-olefin and a preparation method thereof, wherein the reaction conditions are relatively mild, which reduces energy consumption and equipment requirements. Such mild conditions make the catalytic reaction easier to control and reduce the probability of side reactions.

[0022] 3. The present invention provides a high molecular weight polylinear α-olefin and a preparation method thereof, wherein the reaction steps are simple and clear, and the processes such as mixing, adding catalyst, reaction and post-treatment are easy to operate, which reduces the process complexity and is conducive to the implementation of industrial production;

[0023] 4. The present invention provides a high molecular weight polylinear α-olefin and a preparation method thereof. Compared with the traditional Lewis acid catalyst, the combination of the metallocene catalyst and the organic boron compound reduces the generation of wastewater and reduces the risk of environmental pollution, which makes the method more in line with the requirements of modern green chemistry;

[0024] 5. The present invention provides a high molecular weight polylinear α-olefin and a preparation method thereof. The catalyst cost used in the method is relatively low, and the production cost is further reduced by using industrial grade alkyl aluminum as a scavenger (not reagent grade or commonly used trimethyl aluminum or triethyl aluminum), which improves the economic efficiency of large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the molecular weight and distribution of the products obtained in Examples 1 to 5. DETAILED DESCRIPTION

[0026] In the present invention, the reagents or solvents are all solvents with extremely low water and oxygen content after post-treatment. In addition, in the process of preparing high molecular weight polylinear α-olefin, all operations sensitive to water and oxygen are performed by professionals familiar with the technology in the field in MBraun glove box or Schlenk technology under nitrogen protection. The molecular weight and molecular weight distribution of the obtained copolymer are characterized by gel chromatography GPC for the obtained high molecular weight polylinear α-olefin, and the dissolving reagent is HPLC grade tetrahydrofuran.

[0027] Example 1

[0028] 4 mL of toluene was added to 20 mL of 1-decene to obtain a mixed solution, and the mixed solution was stirred for 3 minutes, and then 2.8 mL of industrial-grade triisobutylaluminum was added thereto, and the mixture was stirred again for 5 minutes. The heating equipment was heated to 40°C, and then the catalyst system solution (containing 5.3 mg of zirconocene catalyst and 5.8 mg of triphenylcarbon tetrakis(pentafluorophenyl)borate) was added thereto. The solvent system underwent an obvious purple color change, marking the start of the reaction, and the total reaction time was 180 minutes. After the reaction was completed, a quencher (ethanol and concentrated hydrochloric acid in a volume ratio of 14) was added thereto, and then the mixture was allowed to stand for stratification, the upper layer was collected and washed with 40 mL of deionized water, and then a rotary evaporation operation was performed to obtain a high molecular weight polylinear α-olefin product. The molecular weight and distribution analysis of the obtained product are shown in Tables 1 and Figure 1 .

[0029] Example 2

[0030] 8 mL of toluene was added to 20 mL of 1-decene to obtain a mixed solution, and the mixed solution was stirred for 3 minutes, and then 0.7 mL of industrial-grade triisobutylaluminum was added thereto, and the mixture was stirred again for 5 minutes. The heating equipment was heated to 100°C, and then the catalyst system solution (containing 3.5 mg of zirconocene catalyst and 7.7 mg of triphenylcarbon tetrakis(pentafluorophenyl)borate) was added thereto. The solvent system underwent an obvious purple color change, marking the start of the reaction, and the total reaction time was 70 minutes. After the reaction was completed, a quencher (ethanol and concentrated hydrochloric acid in a volume ratio of 8) was added thereto, and then the mixture was allowed to stand for stratification. The upper layer was collected and washed with 30 mL of deionized water, and then a rotary evaporation operation was performed to obtain a high molecular weight polylinear α-olefin product. The molecular weight and distribution analysis of the obtained product are shown in Tables 1 and Figure 1 .

[0031] Example 3

[0032] Add 10 mL of toluene to 20 mL of 1-decene to obtain a mixed solution, stir the mixed solution for 3 minutes, then add 2.1 mL of industrial-grade triisobutylaluminum, and stir again for 5 minutes. The heating equipment is heated to 60°C, and then the catalyst system solution (containing 4.8 mg of zirconocene catalyst and 16.1 mg of triphenylcarbon tetrakis(pentafluorophenyl)borate) is added thereto. The solvent system undergoes an obvious purple color change, which marks the start of the reaction. The total reaction time is 100 minutes. After the reaction is completed, a quencher (ethanol and concentrated hydrochloric acid in a volume ratio of 10) is added thereto, and then the layers are allowed to stand and the upper layer is collected and washed with 10 mL of deionized water, followed by rotary evaporation to obtain a high molecular weight polylinear α-olefin product. The molecular weight and distribution analysis of the obtained product are shown in Tables 1 and Figure 1 .

[0033] Example 4

[0034] Add 10 mL of toluene to 20 mL of 1-decene to obtain a mixed solution, stir the mixed solution for 3 minutes, then add 1.0 mL of industrial-grade triisobutylaluminum, and stir again for 5 minutes. The heating equipment is heated to 70°C, and then the catalyst system solution (containing 3.9 mg of zirconocene catalyst and 26.3 mg of triphenylcarbon tetrakis(pentafluorophenyl)borate) is added thereto. The solvent system undergoes an obvious purple color change, marking the start of the reaction, and the total reaction time is 140 minutes. After the reaction is completed, a quencher (ethanol and concentrated hydrochloric acid in a volume ratio of 12) is added thereto, and then the layers are allowed to stand and stratify. The upper layer is collected and washed with 16 mL of deionized water, and then a rotary evaporation operation is performed to obtain a high molecular weight polylinear α-olefin product. The molecular weight and distribution analysis of the obtained product are shown in Tables 1 and Figure 1 .

[0035] Example 5

[0036] 10 mL of toluene was added to 20 mL of 1-decene to obtain a mixed solution, and the mixed solution was stirred for 3 minutes, and then 1.4 mL of industrial-grade triisobutylaluminum was added thereto, and the mixture was stirred again for 5 minutes. The heating equipment was heated to 80°C, and then the catalyst system solution (containing 4.4 mg of zirconocene catalyst and 19.4 mg of triphenylcarbon tetrakis(pentafluorophenyl)borate) was added thereto. The solvent system underwent an obvious purple color change, marking the start of the reaction, and the total reaction time was 120 minutes. After the reaction was completed, a quencher (ethanol and concentrated hydrochloric acid in a volume ratio of 11) was added thereto, and then the mixture was allowed to stand for stratification, the upper layer was collected and washed with 22 mL of deionized water, and then a rotary evaporation operation was performed to obtain a high molecular weight polylinear α-olefin product. The molecular weight and distribution analysis of the obtained product are shown in Tables 1 and Figure 1 .

[0037] Table 1 Molecular weight and distribution of products obtained in Examples 1 to 5

[0038]

[0039]

[0040] From Table 1 and Figure 1 It can be obtained that the high molecular weight polylinear α-olefin product prepared by the present invention has better environmental friendliness and narrower product distribution (PDI value is less than 2.9) compared with the traditional Lewis acid catalyst, and the obtained product maintains a molecular weight in the range of 17000 to 23000 g / mol.

[0041] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0042] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing high molecular weight polylinear α-olefin, characterized in that: The preparation method uses metallocene compounds to provide effective metal active centers, uses alkyl aluminum as a scavenger to remove impurities in the catalyst system, and introduces organic boron compounds as auxiliary agents for the anionic catalyst environment; The molecular weight distribution range of the prepared polylinear alpha-olefin is 17000-23000 g / mol.

2. The preparation method according to claim 1, characterized in that: The following steps are involved: After a certain proportion of polymerization monomers are mixed with a diluent solvent and alkyl aluminum, a metallocene catalyst and an organic boron compound are added in sequence to carry out a polymerization reaction. After the reaction is completed, a quencher is added to terminate the reaction, followed by standing and stratification, washing and rotary evaporation to finally obtain the high molecular weight polylinear α-olefin.

3. The preparation method according to claim 2, characterized in that: The polymerization monomer is 1-decene, the alkyl aluminum is industrial-grade triisobutyl aluminum and / or triisomethyl aluminum, the metallocene catalyst is rac-ethylene bis(1-indenyl) zirconium dichloride, and the organic boron compound is tri(pentafluorophenyl) borane and / or triphenylcarbon tetrakis(pentafluorophenyl) borate and / or N,N-dimethylanilinium tetrakis(pentafluorophenyl) borate and / or industrial-grade methylaluminoxane.

4. The preparation method according to claim 3, characterized in that: The molar ratio of the metallocene catalyst to 1-decene is 7×10 -5 ~12×10 -5 ; The molar ratio of the organic boron compound to the metallocene catalyst is 0.5 to 3.0, and the molar ratio of the alkyl aluminum to the metallocene catalyst is 50 to 250.

5. The preparation method according to claim 2, characterized in that: The polymerization monomer is 1-decene, the dilution solvent is toluene, and the volume ratio of toluene to 1-decene is 0.2-1.

0.

6. The preparation method according to claim 2, characterized in that: The control conditions of the polymerization reaction are: The reaction temperature is 40-100°C and the reaction time is 60-180min.

7. The preparation method according to claim 2, characterized in that: The quenching agent is an acidified ethanol solution, the acidifying agent is concentrated hydrochloric acid, wherein the volume ratio of ethanol to concentrated hydrochloric acid is 8-14.

8. The preparation method according to claim 2, characterized in that: The washing process is to wash the deionized water to remove the layers, wherein the volume ratio of the deionized water to the reactants is 0.5 to 2.

0.

9. The high molecular weight polylinear α-olefin prepared by the preparation method according to any one of claims 1 to 8.

10. The high molecular weight polylinear α-olefin according to claim 9, characterized in that The molecular weight distribution index of the prepared high molecular weight polylinear alpha-olefin is between 2.0 and 2.9.

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