CN114507305A - Method for synthesizing zirconocene type olefin polymerization catalyst - Google Patents

Method for synthesizing zirconocene type olefin polymerization catalyst Download PDF

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CN114507305A
CN114507305A CN202210097960.9A CN202210097960A CN114507305A CN 114507305 A CN114507305 A CN 114507305A CN 202210097960 A CN202210097960 A CN 202210097960A CN 114507305 A CN114507305 A CN 114507305A
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王博
徐宇航
段亚轩
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Abstract

The invention relates to a method for synthesizing a zirconocene type olefin polymerization catalyst, belonging to the technical field of synthesis of organic and high molecular materials. Reacting 3-bromothiophene with strong base, and performing methylation reaction on the 3-bromothiophene and iodomethane to obtain 2-methyl-3-bromothiophene; then carrying out Friedel-crafts acylation reaction, Nazaro cyclization reaction and Suzuki coupling reaction to obtain 2, 5-dimethyl-3-phenyl-5, 6-dihydrocyclopentane [1,2-b ] thiophene-4-ketone; reducing and eliminating to obtain 2, 5-dimethyl-3-phenyl-6-cyclopentene [1,2-b ] thiophene; finally, the target zirconocene type olefin polymerization catalyst is obtained after silica-based and zirconium salt coordination. The synthesis condition of the invention is relatively mild, the cost of the synthesis method is low, the energy consumption is low, and the invention is beneficial to realizing the industrial production of the catalyst.

Description

Method for synthesizing zirconocene type olefin polymerization catalyst
Technical Field
The invention belongs to the technical field of synthesis of metal organic and high polymer materials, and particularly relates to a synthesis method of a zirconocene type olefin polymerization catalyst.
Background
Polypropylene is one of the fastest growing polyolefin resins in recent years, and a key factor in the rapid development thereof is the rapid development of polymerization catalyst-related technologies. The catalyst plays a significant role in the polypropylene production technology, and the catalyst system has important influence on the performance (such as relative molecular mass and distribution, product form, random polymer content and the like), conversion rate, production conditions (such as operation temperature), catalyst residual amount in the product and the like of a polypropylene product.
In the research and development of polypropylene catalysts, increasing the catalytic activity and stereoselectivity of the catalysts and improving the production economy of the catalysts are always the key points of research and development. Compared with the traditional Z-N catalyst, the metallocene catalyst has the characteristic of a single active center, and can more accurately control the relative molecular mass and the distribution of the polymer, the crystal structure and the insertion mode of the comonomer on the polymer molecular chain; the electronic distribution around the metal center can be changed by adjusting the structure of the ligand, so that the structure and the mechanical property of the polymer product are influenced. Metallocene polypropylene (mPP) produced by catalytic polymerization of a metallocene catalyst has the advantages of narrow relative molecular mass distribution, low crystallinity, small crystallite, high transparency, excellent glossiness, excellent impact strength and toughness and the like. Meanwhile, the mPP also has the characteristics of good radiation resistance and insulation and good compatibility with other polymers. Therefore, in recent years, metallocene catalysts have been rapidly developed in the industrial production of polypropylene.
The catalytic production of propylene copolymers with metallocene catalysts is another important application of metallocene catalysts in the field of olefin polymerization: the metallocene catalyst can catalyze and synthesize a plurality of propylene copolymers which are difficult to catalyze and synthesize by Z-N catalysts, such as random and block copolymers of propylene and styrene, copolymers of propylene and long-chain olefin, cycloolefin and diene, and the like. Compared with the traditional catalytic system, when the metallocene catalyst is used for producing the random copolymer, the random insertion of the comonomer is good, and the catalyst can be used for synthesizing the random copolymer with high comonomer content and has the potential of developing high-performance low-temperature heat sealing materials. The propylene-ethylene copolymer with bimodal distribution is synthesized in a single reactor by the company Exon by adopting a metallocene catalyst, the processing temperature range of the propylene-ethylene copolymer is about 26 ℃, the processing temperature range (15 ℃) of the propylene-ethylene copolymer is wider than that of the common propylene copolymer, the defect that the processing temperature range of the traditional unimodal mPP resin is narrow is overcome, the BOPP film is stretched more uniformly and is not easy to break when being produced, and the polypropylene film with good performance can be produced at the temperature lower than the processing temperature of the traditional polypropylene.
ExxonMobil, LyondellBasell, Dow chemical and iFan (now Total petrochemical) are the leading players in the development of mPP catalysts, and second generation mPP catalysts have been developed, and some companies have begun to produce mPP industrially based on the developed catalysts. Due to the protection of intellectual property rights, the high cost of the catalyst and the continuous improvement of the traditional Z-N catalyst, the development of mPP is still slow on the whole, the mPP is not widely applied, but the development potential is huge.
The development and research of metallocene catalysts and mPP have been carried out in China since 1993, but the domestic mPP is still in the beginning stage until now. In 2001, Arnold L.Rheingold et al reported the synthesis of 6,6' -dimethylsilylbis (2, 5-dimethyl-3-phenyl-thieno [2,3-b ] metallocene) and zirconium dichloride (J.Am.chem.Soc. 2001,123,4763-4773), but the method takes polyphosphoric acid and phosphorus pentoxide as reaction reagents, is expensive and difficult to operate, can generate a large amount of waste acid emission, is not beneficial to industrial production, and runs counter to the goal of realizing carbon peak-reaching carbon neutralization in China.
Disclosure of Invention
The invention aims to solve the problems of complex and harsh conditions, high cost and high energy consumption of the existing method for synthesizing the zirconocene type olefin polymerization catalyst, and provides a method for synthesizing the zirconocene type olefin polymerization catalyst. The zirconocene type olefin polymerization catalyst of the invention can efficiently solve the problem of control of isotacticity in metallocene polypropylene production, and can catalyze and synthesize polypropylene with high isotacticity.
The technical scheme of the invention is as follows:
a method for synthesizing a zirconocene type olefin polymerization catalyst comprises the following steps:
the method comprises the following steps: reacting 3-bromothiophene with strong base, and performing methylation reaction on the 3-bromothiophene and iodomethane to obtain 2-methyl-3-bromothiophene;
step two: 2-methyl-3-bromothiophene is subjected to Friedel-crafts acylation reaction, Nazaro cyclization reaction and Suzuki coupling reaction to obtain 2, 5-dimethyl-3-phenyl-5, 6-dihydrocyclopentane [1,2-b ] thiophene-4-ketone;
step three: 2, 5-dimethyl-3-phenyl-5, 6-dihydrocyclopentane [1,2-b ] thiophene-4-ketone is reduced and eliminated to obtain 2, 5-dimethyl-3-phenyl-6-cyclopentene [1,2-b ] thiophene;
step four: the target zirconocene type olefin polymerization catalyst is obtained by carrying out silicatization and coordination with zirconium salt on 2, 5-dimethyl-3-phenyl-6-cyclopentene [1,2-b ] thiophene.
The structure of the zirconocene type olefin polymerization catalyst is as follows:
Figure BDA0003491697930000031
preferably, the strong base in step one is selected from n-butyllithium, isobutyllithium, diisopropyllithium or hexamethyldisilazane, sodium hexamethyldisilazane or potassium hexamethyldisilazane.
Preferably, the molar ratio of the 3-bromothiophene, the strong base and the methyl iodide in the first step is 1: (1-2): (1-2); the reaction temperature of the methylation reaction is-80-100 ℃, and the reaction time is 30 minutes-7 days.
Preferably, the catalyst used in the friedel-crafts acylation reaction in the second step is selected from aluminum trichloride, aluminum tribromide, aluminum triiodide, tin tetrachloride, titanium tetrachloride or zinc chloride; the acylating agent used is selected from methacryloyl chloride, methacrylic anhydride, methacrylic acid, sodium methacrylate or methyl methacrylate; the solvent used is selected from dichloromethane or dichloroethane; wherein the molar ratio of the 2-methyl-3-bromothiophene to the acylating agent to the catalyst is 1: (1-5): (1-5); the reaction temperature is-80 to 100 ℃, and the reaction time is 1 to 48 hours.
Preferably, the catalyst used in the Nazarov cyclization reaction in the second step is selected from perfluorosulfonic acid resin, solid acid catalyst, sulfuric acid, phosphoric acid or trifluoroacetic acid, and the molar mass ratio of the raw material to the catalyst is 1mmol: (0.5-10 g); the solvent used is selected from toluene, ethylbenzene or xylene; the reaction temperature is 0-200 ℃, and the reaction time is 1-48 hours.
Preferably, the suzuki coupling reaction in step two uses a catalyst selected from tetrakis (triphenylphosphine) palladium, tetrakis (triphenylphosphine) platinum, bis (triphenylphosphine) palladium dichloride, palladium on carbon, palladium black or palladium-calcium carbonate; the alkali is selected from potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide or potassium trimethylsilanolate; the phenylating agent used is selected from phenylboronic acid, sodium phenylboronate, phenylboronic anhydride or pinacol ester of phenylboronic acid; the solvent used is selected from toluene, ethylbenzene or xylene; wherein the molar ratio of the reaction raw materials to the alkali, the phenylating reagent and the catalyst is 1: (1-5): (1-5): (0.0001 to 1); the reaction temperature is 100-200 ℃, and the reaction time is 10 minutes-48 hours.
Preferably, the reducing agent used in the reduction reaction in step three is selected from sodium borohydride, lithium aluminum hydride, borane-tetrahydrofuran or borane-dimethyl sulfide; wherein the molar ratio of the raw material to the reducing agent is 1: (0.1-2); the reaction temperature is-50 ℃ to 100 ℃, and the reaction time is 1 minute to 48 hours.
Preferably, the catalyst used in the elimination reaction in step three is selected from p-toluenesulfonic acid monohydrate, p-toluenesulfonic acid pyridinium salt, pyridine hydrochloride, pyridine sulfate, camphorsulfonic acid, phenylboronic acid, sulfuric acid or hydrochloric acid; the solvent used is selected from tetrahydrofuran, dichloroethane, 1, 4-dioxane, toluene, xylene or ethylbenzene; wherein the molar ratio of the raw materials to the catalyst is (1-5): 1; the reaction temperature is-50 to 200 ℃, and the reaction time is 10 minutes to 48 hours.
Preferably, the strong alkaline reagent used in the silicification reaction in step four is selected from n-butyllithium, isobutyllithium, tert-butyllithium, methyllithium, diisopropylaminolithium, hexamethyldisilazane lithium, hexamethyldisilazane sodium or hexamethyldisilazane potassium; the silane reagent used is selected from dichlorodimethylsilane, dibromodimethylsilane or dimethylsilane bistrifluoromethanesulfonate; the solvent used is selected from diethyl ether, dichloromethane, dichloroethane, n-butyl ether or methyl tert-butyl ether; wherein the molar ratio of the raw material to the alkali reagent to the silane reagent is 1: (1-5): (0.2-5); the reaction temperature is-80-100 ℃, and the reaction time is 1 minute-48 hours.
Preferably, the strong alkaline reagent used in the coordination reaction in step four is selected from n-butyllithium, isobutyllithium, tert-butyllithium, methyllithium, diisopropylaminolithium, hexamethyldisilazane lithium, hexamethyldisilazane sodium or hexamethyldisilazane potassium; the zirconium salt used is selected from anhydrous zirconium tetrachloride or bis (tetrahydrofuran) zirconium tetrachloride; the solvent used is selected from diethyl ether, dichloromethane, dichloroethane, n-butyl ether or methyl tert-butyl ether; wherein the molar ratio of the ligand to the strong alkaline reagent and the zirconium salt is 1: (1-5): (0.2-5); the reaction temperature is 0-100 ℃, and the reaction time is 1-48 hours.
Has the beneficial effects that:
the invention provides a method for synthesizing a zirconocene type olefin polymerization catalyst, which comprises the steps of reacting 3-bromothiophene with strong base, and carrying out methylation reaction with methyl iodide to obtain 2-methyl-3-bromothiophene; then 2-methyl-3-bromothiophene is subjected to Friedel-crafts acylation reaction, Nazaro cyclization reaction and Suzuki coupling reaction to obtain 2, 5-dimethyl-3-phenyl-5, 6-dihydrocyclopentane [1,2-b ] thiophene-4-ketone; reducing and eliminating to obtain 2, 5-dimethyl-3-phenyl-6-cyclopentene [1,2-b ] thiophene; finally, reacting the 2, 5-dimethyl-3-phenyl-6-cyclopentene [1,2-b ] thiophene with a strong base reagent, carrying out silica-based reaction, and coordinating with zirconium salt to obtain the target zirconocene type olefin polymerization catalyst. Compared with the prior art, the synthesis process has relatively mild conditions, low cost and low energy consumption, is beneficial to realizing the industrial production of the catalyst, and provides good support for the research and development of the type of catalyst in China, particularly for industrialization; is helpful for developing novel olefin polymers with special functions, in particular to the development of novel polypropylene materials, novel ethylene-octene copolymer materials and other polymer materials.
Drawings
FIG. 1 shows the nuclear magnetic hydrogen spectrum of 6,6' -dimethylsilylbis (2, 5-dimethyl-3-phenyl-thieno [2,3-b ] metallocene) zirconium dichloride synthesized in example 1 of the present invention.
Detailed Description
The present invention is further described in detail below with reference to examples, in which all of the materials are commercially available.
Example 1
Step one, synthesis of 2-methyl-3-bromothiophene
Figure BDA0003491697930000051
Diisopropylamine (56ml, 363mmol) was dissolved in 200ml dry tetrahydrofuran, cooled to-78 ℃ and n-butyllithium (2.5M n-hexane solution, 140ml, 330mmol) was added and after the addition was complete stirring continued at-78 ℃ for 15 min. To a solution containing Lithium Diisopropylamide (LDA) was added 3-bromothiophene (50g, 307mmol) dropwise. After the addition was complete, the reaction was transferred to an ice bath to allow it to rise naturally to 0 ℃ and stirred for 30 min. The reaction was cooled to-78 ℃ and methyl iodide (21ml, 330mmol) was slowly added dropwise. The reaction mixture was stirred at-78 ℃ for a further 30min, then brought to 0 ℃ and stirred for 1 h. After the reaction, the reaction solution was quenched with saturated brine, separated, and the aqueous phase was extracted with dichloromethane, washed with water, separated, dried over magnesium sulfate, filtered, and the solvent was removed in vacuo. The residue was distilled under reduced pressure to give colorless oily liquid 2(46.80g, 86%).1H NMR(400MHz,chloroform-d)δ7.07 (d,J＝5.4Hz,1H),6.90(d,J＝5.4Hz,1H),2.41(s,3H).
Step two, synthesis of 2, 5-dimethyl-3-phenyl-5, 6-dihydrocyclopentane [1,2-b ] thiophene-4-ketone
Figure BDA0003491697930000052
Aluminum trichloride (56.4g, 423mmol) is suspended in 500ml of dry dichloromethane in a 1L three-neck flask, 2-methyl-3-bromothiophene (50g, 282mmol) is slowly dropped under the protection of argon gas and cooling of an ice water bath, and stirring is carried out for 5min after dropping. Then slowly dripping a solution of methacrylic anhydride (63ml, 423mmol) dissolved in 100ml of dry dichloromethane, stirring for 30min after dripping to obtain a dark black red solution, and controlling the temperature to ensure that the temperature in the bottle is not higher than 10 ℃ during the dripping process. TLC monitored the disappearance of starting material and slowly poured into ice water to quench. The phases were separated and the aqueous phase was extracted with dichloromethane, the organic phases combined, washed with water, separated, dried over magnesium sulfate, filtered and the solvent removed in vacuo to give 3(58.80g, 85%) as an orange-yellow oil which was used directly in the next synthesis without further purification.
In a 500ml round bottom flask, 3 was dissolved in 250ml dichloroethane, concentrated sulfuric acid (24ml, 1ml/mmol) was added dropwise under cooling in an ice bath, taken out from the ice bath after completion of the dropwise addition, naturally warmed to room temperature and stirred for 2 hours, and disappearance of the starting material was monitored by TLC. Slowly pouring into ice water for quenching, separating liquid, washing an aqueous phase with dichloroethane, combining a washing liquid and an organic phase, drying with anhydrous magnesium sulfate, filtering, and removing the solvent in vacuum to obtain brown oily liquid 4, wherein the brown oily liquid 4 is solidified into yellow needle crystals (45.92g, 78%) after being purified by column chromatography.1H NMR(400MHz,Chloroform-d)δ3.15 (dd,J＝17.4,6.9Hz,1H),2.97(pd,J＝7.4,2.6Hz,1H),2.50(s,3H),2.49(dd,J＝17.3, 2.7Hz,1H),1.33(d,J＝7.5Hz,3H).
In a 1L round bottom flask, potassium hydroxide (21.12g, 376mmol), phenylboronic acid (45.62g, 374mmol) were dissolved in 200mL water, compound 4 from the previous step was dissolved in 200mL dioxane, the two were combined, tetrakis (triphenylphosphine) palladium (0.14g, 0.12mmol) was added with stirring and heated to reflux for 3h until TLC monitored disappearance of starting material. Cooling, separation of the layers, extraction of the aqueous phase with dichloromethane, combination of the washings with the organic phase, drying over anhydrous magnesium sulphate, filtration and removal of the solvent in vacuo gave a brown oily liquid 5 which solidified to an off-white solid (40.80g, 90%) after purification by column chromatography.1H NMR(400MHz,Chloroform-d)δ7.47(td,J＝7.2,6.3, 1.4Hz,2H),7.42–7.25(m,3H),3.18(dd,J＝17.3,6.8Hz,1H),2.97(pd,J＝7.4, 2.7Hz,1H),2.54(s,3H),2.54(dd,J＝17.3,2.7Hz,1H),1.33(d,J＝7.5Hz,3H).
Step three, synthesizing 2, 5-dimethyl-3-phenyl-6-cyclopentene [1,2-b ] thiophene
Figure BDA0003491697930000061
Compound 5(24.2g, 100mmol) was dissolved in 200ml of anhydrous tetrahydrofuran in a 500ml round bottom flask, and after cooling to 0 ℃ in an ice water bath, lithium aluminum hydride (3.81g, 100mmol) was slowly added. After the addition, the ice-water bath was removed, the reaction flask was allowed to warm to room temperature, and stirred for 1h, after which the reaction was monitored by TLC. Slowly adding dilute hydrochloric acid to quenchThe reaction solution is quenched, separated, the aqueous phase is extracted with dichloromethane, the organic phases are combined, washed with water, dried over magnesium sulfate, filtered and the solvent is removed in vacuo to give a white solid 7. 7 was dissolved without purification in 100ml of toluene, p-toluenesulfonic acid monohydrate (2g, 10mmol) was added and heated to reflux. 1.5h later TLC monitored disappearance of starting material, cooling, water washing, liquid separation, anhydrous magnesium sulfate drying, filtration, solvent removal in vacuo to afford 7 (21.69g, 96%) as a brown oil, which solidified to an off-white solid after purification of 7 by column chromatography.1H NMR(400MHz, Chloroform-d)δ7.42(d,J＝5.3Hz,4H),7.37–7.27(m,1H),6.42(q,J＝1.6Hz,1H), 3.13(d,J＝1.4Hz,2H),2.50(s,3H),2.14(d,J＝1.6Hz,3H).
Step four, 6' -dimethyl silicon base bi (2, 5-dimethyl-3-phenyl-thieno [2,3-b ] cyclopentadienyl) zirconium dichloride synthesis
Figure BDA0003491697930000071
In a 250ml round-bottom flask, compound 7(11.35g, 50mmol) was dissolved in 65ml dry tetrahydrofuran, cooled to-78 ℃ under argon protection, n-butyllithium (2.5M n-hexane solution, 20ml, 50mmol) was slowly added dropwise thereto, and after dropping, the mixture was warmed to room temperature to react for 12 hours, giving a deep red solution. The lithium salt solution was cooled to-78 ℃ again, dimethyldichlorosilane (3.55g, 27.5mmol) was added dropwise thereto, and the reaction was carried out at room temperature for 12 hours after the dropwise addition, whereby a large amount of white precipitate was precipitated. Suction filtration, ether washing and drying gave compound 8 as an off-white solid (18.5g, 72%) which was used for the next step without further purification of compound 8.
Compound 8(2.5g, 4.9mmol) was added to a 250ml round bottom flask, 125ml dry ether was added and stirred, at which time compound 8 was suspended in ether as a white suspension. Slowly dripping n-butyllithium (2.5M n-hexane solution, 4ml and 10mmol) into the mixture at room temperature under the protection of argon, gradually dissolving the mixture into orange yellow clear solution along with the dripping of solid, and reacting for 12 hours at room temperature after dripping. Transferring the obtained lithium salt solution into a glove box, adding anhydrous zirconium tetrachloride powder (0.58g, 2.5mmol) in portions, adding zirconium salt into the reaction product to generate a large amount of yellow turbidity, and storing in a roomStirring for 12h under warm sealing. Suction filtration, ether washing and drying gave compound 9(2.30g, 70%) as a bright yellow solid. The nuclear magnetic hydrogen spectrum is shown in FIG. 1.1H NMR(600MHz,Chloroform-d)δ7.52–7.47 (m,4H),7.42(dd,J＝8.6,6.9Hz,4H),7.31(ddt,J＝8.7,7.2,1.3Hz,2H),6.60(s,2H),2.54(s,6H), 2.33(s,6H),1.07(s,6H)。
Example 2
Step one, synthesis of 2-methyl-3-bromothiophene
3-bromothiophene (50g, 307mmol) was dissolved in 200ml of anhydrous tetrahydrofuran, cooled to-78 deg.C, and lithium hexamethyldisilazide (2M in tetrahydrofuran, 165ml, 330mmol) was added, after which stirring was continued at-78 deg.C for 15 min. The reaction was then transferred to an ice-water bath, allowed to rise to 0 ℃ naturally, and stirred for another 30 min. The reaction was cooled to-78 ℃ and methyl iodide (21ml, 330mmol) was slowly added dropwise. The reaction mixture was stirred at-78 ℃ for a further 30min, then brought to 0 ℃ and stirred for 1 h. After the reaction, the reaction solution was quenched with saturated brine, separated, and the aqueous phase was extracted with dichloromethane, washed with water, separated, dried over magnesium sulfate, filtered, and the solvent was removed in vacuo. The residue was distilled under reduced pressure to give a colorless oily liquid (38.11g, 70%).
Step two, synthesis of 2, 5-dimethyl-3-phenyl-5, 6-dihydrocyclopentane [1,2-b ] thiophene-4-ketone
Tin tetrachloride (110.20g, 423mmol) is dissolved in 500ml of dry dichloromethane in a 1L three-neck flask, 2-methyl-3-bromothiophene (50g, 282mmol) is slowly dropped under the protection of argon gas and cooling of an ice water bath, and stirring is carried out for 5min after dropping. Then slowly dripping a solution of methacrylic anhydride (63ml, 423mmol) dissolved in 100ml of dry dichloromethane, stirring for 30min after dripping to obtain a dark black red solution, and controlling the temperature to ensure that the temperature in the bottle is not higher than 10 ℃ during the dripping process. TLC monitored the disappearance of starting material and slowly poured into ice water to quench. The phases were separated and the aqueous phase was extracted with dichloromethane, the organic phases combined, washed with water, separated, dried over magnesium sulfate, filtered and the solvent removed in vacuo to give 3(45.10g, 65%) as an orange-yellow oil which was used directly in the next synthesis without further purification.
In a 500ml round bottom flask 3 was dissolved in 250ml xylene, perfluorosulfonic acid resin (18g, 10mmol/g) was added, refluxed at 135 ℃ for 5h and monitored by TLC for disappearance of starting material. Suction filtration, washing of the solid with dichloromethane, combining the washings with the filtrate, drying over anhydrous magnesium sulfate, filtration, and solvent removal in vacuo gave brown oily liquid 4, which after purification by column chromatography solidified to yellow needle crystals (36.22g, 80%).
In a 1L round bottom flask potassium carbonate (41.46g, 300mmol), phenylboronic acid (36.10g, 296mmol) were mixed in 200ml xylene, compound 4 from the above step dissolved in 100ml xylene, the two were mixed and after addition of tetrakis (triphenylphosphine) palladium (0.21g, 0.18mmol) with stirring, heated to reflux for 5h until disappearance of the starting material as monitored by TLC. Cooling, separating, extracting the aqueous phase with dichloromethane, combining the washings with the organic phase, drying over anhydrous magnesium sulfate, filtering, and removing the solvent in vacuo to give brown oily liquid 5, which after column chromatography purification solidified to a beige solid (41.02g, 90%).
Step three, synthesizing 2, 5-dimethyl-3-phenyl-6-cyclopentene [1,2-b ] thiophene
Compound 5(24.2g, 100mmol) was dissolved in 200ml of anhydrous tetrahydrofuran in a 500ml round bottom flask, and after cooling to 0 ℃ in an ice water bath, borane-tetrahydrofuran (1M tetrahydrofuran solution, 100ml, 100mmol) was added slowly. After the addition, the ice-water bath was removed, the reaction flask was allowed to warm to room temperature, and stirred for 1h, after which the reaction was monitored by TLC. Slowly adding dilute hydrochloric acid for quenching, separating liquid, extracting an aqueous phase by using dichloromethane, combining organic phases, washing by water, drying by magnesium sulfate, filtering, and removing the solvent in vacuum to obtain a white solid 7. 7 was dissolved without purification in 100ml of toluene, and pyridinium p-toluenesulfonate (2.5g, 10mmol) was added and heated to reflux. 1.5h later TLC monitored disappearance of starting material, cooling, water washing, liquid separation, anhydrous magnesium sulfate drying, filtration, solvent removal in vacuo to afford 7(20.41g, 90%) as a brown oily liquid which solidified to an off-white solid after purification of 7 by column chromatography.
Step four, 6' -dimethyl silicon base bi (2, 5-dimethyl-3-phenyl-thieno [2,3-b ] cyclopentadienyl) zirconium dichloride synthesis
Compound 7(11.35g, 50mmol) was dissolved in 65ml of dry tetrahydrofuran in a 250ml round bottom flask, cooled to-78 ℃ under argon atmosphere, methyllithium (1.6M in ether, 31.3ml, 50mmol) was slowly added dropwise thereto, and the mixture was allowed to warm to room temperature for 12h to obtain a deep red solution. The lithium salt solution was cooled to-78 ℃ again, dimethyldichlorosilane (3.55g, 27.5mmol) was added dropwise thereto, and the reaction was carried out at room temperature for 12 hours after the dropwise addition, whereby a large amount of white precipitate was precipitated. Suction filtration, ether washing and drying gave compound 8 as an off-white solid (19.77g, 77%) which was used for the next step without further purification of compound 8.
Compound 8(2.5g, 4.9mmol) was added to a 250ml round bottom flask, 125ml dry ether was added and stirred, at which time compound 8 was suspended in ether as a white suspension. Slowly dropping methyl lithium (1.6M ether solution, 3.1ml and 4.9mmol) into the mixture under the protection of argon at room temperature, gradually dissolving the mixture into orange yellow clear solution along with dropping solid, and reacting for 12 hours at room temperature after dropping. The resulting lithium salt solution was transferred to a glove box, to which anhydrous zirconium tetrachloride powder (0.58g, 2.5mmol) was added in portions, and the reaction mass was added with zirconium salt to generate a large amount of yellow turbidity, after which the mixture was stirred at room temperature for 12 hours under sealed conditions. Suction filtration, ether washing and drying gave compound 9(2.33g, 71%) as a bright yellow solid.
Example 3
Step one, synthesis of 2-methyl-3-bromothiophene
3-bromothiophene (50g, 307mmol) was dissolved in 200ml of anhydrous tetrahydrofuran, cooled to-78 deg.C, sodium hexamethyldisilazane (2M in tetrahydrofuran, 165ml, 330mmol) was added, and after the addition, stirring was continued at-78 deg.C for 15 min. The reaction was then transferred to an ice-water bath, allowed to rise to 0 ℃ naturally, and stirred for another 30 min. The reaction was cooled to-78 ℃ and methyl iodide (21ml, 330mmol) was slowly added dropwise. The reaction mixture was stirred at-78 ℃ for a further 30min, then brought to 0 ℃ and stirred for 1 h. After the reaction, the reaction solution was quenched with saturated brine, separated, and the aqueous phase was extracted with dichloromethane, washed with water, separated, dried over magnesium sulfate, filtered, and the solvent was removed in vacuo. The residue was distilled under reduced pressure to give a colorless oily liquid (39.70g, 73%).
Step two, synthesis of 2, 5-dimethyl-3-phenyl-5, 6-dihydrocyclopentane [1,2-b ] thiophene-4-ketone
Aluminum trichloride (56.4g, 423mmol) was suspended in 500ml of dry dichloromethane in a 1L three-necked flask, under argon protection, methacryloyl chloride (41ml, 423mmol) was slowly added dropwise with cooling in an ice-water bath, and stirring was carried out for 5min after dropping. Then slowly dripping a solution of 2-methyl-3-bromothiophene (50g, 282mmol) dissolved in 100ml of dry dichloromethane, stirring for 30min after dripping to obtain a dark black red solution, and controlling the temperature to ensure that the temperature in the bottle is not higher than 10 ℃ during the dripping process. TLC monitored the disappearance of starting material and slowly poured into ice water to quench. The phases were separated and the aqueous phase was extracted with dichloromethane, the organic phases combined, washed with water, separated, dried over magnesium sulfate, filtered and the solvent removed in vacuo to give 3 as an orange-yellow oil (65.62g, 95%) which was used in the next synthesis without further purification.
In a 500ml round bottom flask 3 was dissolved in 530ml xylene, solid acid catalyst (26g, 10mmol/g) was added, reflux was carried out at 135 ℃ for 3h and disappearance of starting material was monitored by TLC. Suction filtration, washing of the solid with dichloromethane, combining the washings with the filtrate, drying over anhydrous magnesium sulfate, filtration, and removal of the solvent in vacuo gave a brown oily liquid 4, which after purification by column chromatography solidified to yellow needle crystals (54.51g, 83%).
In a 1L round bottom flask anhydrous sodium carbonate (46.63g, 440mmol), phenylboronic acid (53.65g, 440mmol) were mixed in 250ml xylene, compound 4 from the previous step dissolved in 250ml xylene, the two were mixed and after addition of tetrakis (triphenylphosphine) palladium (0.25g, 0.22mmol) with stirring heated to reflux for 5h until TLC monitored disappearance of starting material. Cooling, separating, extracting the aqueous phase with dichloromethane, combining the washings with the organic phase, drying over anhydrous magnesium sulfate, filtering, and removing the solvent in vacuo to give brown oily liquid 5, which after column chromatography purification solidified to a beige solid (48.44g, 90%).
Step three, synthesizing 2, 5-dimethyl-3-phenyl-6-cyclopentene [1,2-b ] thiophene
Compound 5(24.22g, 100mmol) was dissolved in 200ml of anhydrous methanol in a 500ml round bottom flask, and after cooling to 0 ℃ in an ice water bath, sodium borohydride (3.8g, 100mmol) was slowly added. After the addition, the ice-water bath was removed, the reaction flask was allowed to warm to room temperature, and stirred for 1h, after which the reaction was monitored by TLC. Dilute hydrochloric acid was slowly added to quench, dried over magnesium sulfate, filtered, and the solvent removed in vacuo to give 7 as a white solid. 7 was dissolved without purification in 100ml of toluene, and pyridinium p-toluenesulfonate (2.5g, 10mmol) was added and heated to reflux. After 1.5h the TLC monitored disappearance of starting material, cooled, washed with water, separated, dried over anhydrous magnesium sulfate, filtered and the solvent removed in vacuo to give 7 as an orange-red oily liquid (19.71g, 87%), which solidified to an off-white solid after purification by column chromatography.
Step four, 6' -dimethyl silicon base bi (2, 5-dimethyl-3-phenyl-thieno [2,3-b ] cyclopentadienyl) zirconium dichloride synthesis
Compound 7(11.38g, 50mmol) was dissolved in 65ml of dry tetrahydrofuran in a 250ml round bottom flask, cooled to-78 ℃ under argon atmosphere, methyllithium (1.6M in ether, 31.3ml, 50mmol) was slowly added dropwise thereto, and the mixture was allowed to warm to room temperature for 12h to obtain a dark red solution. The lithium salt solution was cooled to-78 ℃ again, dimethyldichlorosilane (3.55g, 27.5mmol) was added dropwise thereto, and the reaction was carried out at room temperature for 12 hours after the dropwise addition, whereby a large amount of white precipitate was precipitated. Suction filtration, ether washing and drying gave compound 8 as an off-white solid (19.77g, 77%) which was used for the next step without further purification of compound 8.
Compound 8(2.5g, 4.9mmol) was added to a 250ml round bottom flask, 125ml dry ether was added and stirred, at which time compound 8 was suspended in ether as a white suspension. Slowly dropping hexamethyldisilazane lithium amide (2M tetrahydrofuran solution, 2.5ml, 5.0mmol) under the protection of argon at room temperature, gradually dissolving with the dropping solid to obtain a dark yellow clear solution, and reacting at room temperature for 12h after dropping. The lithium salt solution was transferred into a glove box, and then, zirconium bis (tetrahydrofuran) tetrachloride (0.94g, 2.5mmol) powder was added thereto in portions, and as the zirconium salt was added, no noticeable phenomenon was observed at the beginning, yellow turbidity began to form in the reaction after stirring for about 10min, and the amount of solid gradually increased, and after the addition, the mixture was stirred at room temperature for 12 hours under sealed conditions. Suction filtration, ether washing and drying gave compound 9(2.27g, 66%) as a bright yellow solid.
Example 4
A250 mL stainless steel autoclave was replaced with dry propylene gas three times, and then 80mL dry toluene, 1.5mL Methylaluminoxane (MAO) (1M toluene solution) was added thereto, and stirred under a propylene atmosphere. 1.34g (1mmol) of the catalyst prepared in example 1 are weighed out, dissolved in 20mL of toluene, added to the reaction system with vigorous stirring and the temperature is raised.And (3) when the temperature is raised to 50 ℃, filling propylene gas into the reactor, keeping the pressure in the reactor at 1MPa, after 10min, raising the temperature to 60 ℃, reacting for 10min, raising the temperature to 70 ℃, reacting for 10min, and reacting for 30min totally, thus finishing the polymerization reaction. The propylene cylinder was closed and the reaction was stopped. Filtering the generated polymer, washing off residual toluene on the surface by using ethanol, drying, weighing to obtain 27.2g of polypropylene, and obtaining the catalyst with polymerization activity of 2.72 multiplied by 107g/mol/h. The isotactic stereoregularity of the obtained polypropylene product was 99% by nuclear magnetic resonance hydrogen spectroscopy.

Claims (10)

1. A method for synthesizing a zirconocene type olefin polymerization catalyst comprises the following steps:
the method comprises the following steps: reacting 3-bromothiophene with strong base, and performing methylation reaction on the 3-bromothiophene and iodomethane to obtain 2-methyl-3-bromothiophene;
step two: 2-methyl-3-bromothiophene is subjected to Friedel-crafts acylation reaction, Nazaro cyclization reaction and Suzuki coupling reaction to obtain 2, 5-dimethyl-3-phenyl-5, 6-dihydrocyclopentane [1,2-b ] thiophene-4-ketone;
step three: 2, 5-dimethyl-3-phenyl-5, 6-dihydrocyclopentane [1,2-b ] thiophene-4-ketone is reduced and eliminated to obtain 2, 5-dimethyl-3-phenyl-6-cyclopentene [1,2-b ] thiophene;
step four: the target zirconocene type olefin polymerization catalyst is obtained by carrying out silicatization and coordination with zirconium salt on 2, 5-dimethyl-3-phenyl-6-cyclopentene [1,2-b ] thiophene, and has the following structure:
Figure FDA0003491697920000011
2. the method of claim 1, wherein the strong base in step one is selected from n-butyllithium, isobutyllithium, diisopropyllithium, lithium hexamethyldisilazide, sodium hexamethyldisilazide or potassium hexamethyldisilazide.
3. The method for synthesizing a zirconocene type olefin polymerization catalyst according to claim 1, wherein the molar ratio of the 3-bromothiophene, the strong base and the methyl iodide in the first step is 1 (1-2) to (1-2); the reaction temperature of the methylation reaction is-80-100 ℃, and the reaction time is 30 minutes-7 days.
4. The process for synthesizing a catalyst for the polymerization of olefins of the zirconocene type according to claim 1, wherein the catalyst used in the friedel-crafts acylation reaction in the second step is selected from the group consisting of aluminum trichloride, aluminum tribromide, aluminum triiodide, tin tetrachloride, titanium tetrachloride and zinc chloride; the acylating agent used is selected from methacryloyl chloride, methacrylic anhydride, methacrylic acid, sodium methacrylate or methyl methacrylate; the solvent used is selected from dichloromethane or dichloroethane; wherein the molar ratio of the 2-methyl-3-bromothiophene to the acylation reagent to the catalyst is 1 (1-5) to 1-5; the reaction temperature is-80 to 100 ℃, and the reaction time is 1 to 48 hours.
5. The method for synthesizing a zirconocene type olefin polymerization catalyst according to claim 1, wherein the catalyst used in the Nazaloff cyclization reaction in the second step is selected from perfluorosulfonic acid resin, solid acid catalyst, sulfuric acid, phosphoric acid or trifluoroacetic acid, and the molar mass ratio of the raw material to the catalyst is 1mmol (0.5-10 g); the solvent used is selected from toluene, ethylbenzene or xylene; the reaction temperature is 0-200 ℃, and the reaction time is 1-48 hours.
6. The method for synthesizing a zirconocene-type olefin polymerization catalyst according to claim 1, wherein the catalyst used in the Suzuki coupling reaction in step two is selected from tetrakis (triphenylphosphine) palladium, tetrakis (triphenylphosphine) platinum, bis (triphenylphosphine) palladium dichloride, palladium on carbon, palladium black, or palladium-calcium carbonate; the alkali is selected from potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide or potassium trimethylsilanolate; the phenylating agent used is selected from phenylboronic acid, sodium phenylboronate, phenylboronic anhydride or pinacol ester of phenylboronic acid; the solvent used is selected from toluene, ethylbenzene or xylene; wherein the molar ratio of the reaction raw materials to the alkali, the phenylating reagent and the catalyst is 1 (1-5) to 1-5 to 0.0001-1; the reaction temperature is 100-200 ℃, and the reaction time is 10 minutes-48 hours.
7. The method for synthesizing a zirconocene-type olefin polymerization catalyst according to claim 1, wherein the reducing agent used in the reduction reaction in step three is selected from sodium borohydride, lithium aluminum hydride, borane-tetrahydrofuran, or borane-dimethyl sulfide; wherein the molar ratio of the raw material to the reducing agent is 1 (0.1-2); the reaction temperature is-50 ℃ to 100 ℃, and the reaction time is 1 minute to 48 hours.
8. The process for synthesizing a catalyst for the polymerization of olefins of the zirconocene type according to claim 1, wherein the catalyst used in the elimination reaction in step three is selected from the group consisting of p-toluenesulfonic acid monohydrate, p-toluenesulfonic acid pyridinium salt, pyridine hydrochloride, pyridine sulfate, camphorsulfonic acid, phenylboronic acid, sulfuric acid and hydrochloric acid; the solvent used is selected from tetrahydrofuran, dichloroethane, 1, 4-dioxane, toluene, xylene or ethylbenzene; wherein the molar ratio of the raw material to the catalyst is (1-5) to 1; the reaction temperature is-50 to 200 ℃, and the reaction time is 10 minutes to 48 hours.
9. The method of claim 1, wherein the strong basic reagent used in the silylation reaction in the step four is selected from n-butyllithium, isobutyllithium, tert-butyllithium, methyllithium, diisopropylaminium, hexamethyldisilazane, sodium hexamethyldisilazane, and potassium hexamethyldisilazane; the silane reagent used is selected from dichlorodimethylsilane, dibromodimethylsilane or dimethylsilane bistrifluoromethanesulfonate; the solvent used is selected from diethyl ether, dichloromethane, dichloroethane, n-butyl ether or methyl tert-butyl ether; wherein the molar ratio of the raw material to the strong alkali reagent to the silane reagent is 1 (1-5) to 0.2-5; the reaction temperature is-80-100 ℃, and the reaction time is 1 minute-48 hours.
10. The method of claim 1, wherein the strong basic reagent used in the coordination reaction in step four is selected from n-butyllithium, isobutyllithium, tert-butyllithium, methyllithium, diisopropylaminolithium, hexamethyldisilazane, sodium hexamethyldisilazane, and potassium hexamethyldisilazane; the zirconium salt used is selected from anhydrous zirconium tetrachloride or bis (tetrahydrofuran) zirconium tetrachloride; the solvent used is selected from diethyl ether, dichloromethane, dichloroethane, n-butyl ether or methyl tert-butyl ether; wherein the molar ratio of the ligand to the strong alkali reagent to the zirconium salt is 1 (1-5) to 0.2-5; the reaction temperature is 0-100 ℃, and the reaction time is 1-48 hours.
CN202210097960.9A 2022-01-27 2022-01-27 Method for synthesizing zirconocene type olefin polymerization catalyst Pending CN114507305A (en)

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Citations (2)

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CN1347424A (en) * 1999-12-15 2002-05-01 巴塞尔技术有限公司 Metallocene compounds, process for their preparation and their use in catalytic systems for polymerization of olefins
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CN1347424A (en) * 1999-12-15 2002-05-01 巴塞尔技术有限公司 Metallocene compounds, process for their preparation and their use in catalytic systems for polymerization of olefins
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