CN1295087A - Arene-improved double-olefine polymerizing rare earth catalyst and its preparation - Google Patents

Abstract

The invention belongs to a rare earth catalyst for diolefin polymerization improved by aromatic hydrocarbons and a preparation method thereof. The catalyst is composed of rare earth carboxylates, rare earth chloride complexes; organic aluminum compounds; halogen-containing compounds; aromatic hydrocarbons. In the catalyst preparation process, rare earth catalysts with aromatic hydrocarbons are introduced, in addition to maintaining polybutadiene, polyisoprene and butadiene-isoprene with high cis-1,4 content > 95%, high linearity and no gel. In addition to the characteristics of the diene copolymer, it also has the characteristics of significantly improved catalytic activity and the ability to effectively adjust the molecular weight of the polymerization product by changing the type and amount of aromatic hydrocarbons.

Description

Aromatics improved diolefin polymerization rare earth catalyst and preparation method

The invention belongs to a rare earth catalyst for diolefin polymerization improved by aromatic hydrocarbons and a preparation method thereof.

The catalyst composed of rare earth compounds is an effective catalyst system for the high-cis polymerization of butadiene and isoprene, but its catalytic activity and the molecular weight of the polymerization product are mainly adjusted by changing the amount of rare earth compounds and aluminum alkyls. In order to improve the catalytic activity and reduce the molecular weight of the polymerization product, it is necessary to increase the amount of catalyst and aluminum alkyl. Some literatures have reported the effects of a series of compounds with different structures and polarities on the polymerization of diolefins catalyzed by rare earths by introducing additives into the monomer solution, in order to obtain catalytic active agents and molecular weight regulators. Ren Shoujing and others have studied a large number of rare earth catalyzed synthetic rubber collections, the fourth laboratory of Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Science Press, 1980, page 55; Polymer Communications, 1982, No. 6, page 435". According to the characteristics of the additives, only certain allyl derivatives, such as 3-iodopropene and di-α-propene ether, can reduce the molecular weight of the polymer while reducing the catalytic activity. Throckmorton MC discloses a method for regulating the molecular weight of diolefin polymerization products with vinyl chloride and vinyl bromide in U.S. Pat. No. 4,663,405, but the above reagents have certain negative effects on the activity of rare earth catalysts. In addition, Japan Synthetic Rubber Company disclosed a method of mixing aromatic hydrocarbons such as toluene in an aliphatic solvent in the patent GB 2,101,616A to adjust the molecular weight of the polymerization product. The aromatic hydrocarbons in the polymerization medium have the effect of reducing the molecular weight of the polymerization product, but also because of its Participate in the competitive coordination with the monomer on the active center and significantly reduce the catalytic activity of the rare earth catalyst.

The purpose of the present invention is to provide a rare earth catalyst for the polymerization of diolefins improved by aromatics and a preparation method thereof. Rare earth catalysts that introduce aromatic hydrocarbons in the catalyst preparation process, in addition to maintaining polybutadiene, polyisoprene and butadiene-isoprene with high cis-1,4 content > 95%, high linearity and no gel In addition to the characteristics of the diene copolymer, it also has the characteristics of significantly improved catalytic activity and the ability to effectively adjust the molecular weight of the polymerization product by changing the type and amount of aromatic hydrocarbons.

The aromatic hydrocarbons introduced during the preparation of the rare earth catalyst can improve the solubility of the catalyst components and form complexes with the Lewis acid components, which directly participate in the alkylation reaction and become the ligands that form the active center, thus helping to generate a relatively large amount of aromatic hydrocarbons. There are many active centers with high thermal stability, which can reduce the molecular weight of the polymerization product while improving the activity of the rare earth catalyst.

The catalyst composition proposed by the present invention includes a rare earth compound catalyst system represented by LnA ₃ -AlR ₃ -X-Ar and a rare earth chloride catalyst system represented by LnCl ₃ 3L-AlR ₃ -Ar: Ln is a rare earth compound representing La~Lu Elements, among which the most active neodymium Nd and praseodymium Pr are selected; A is a carboxylate, and these carboxylates are naphthenate naph, 2-ethylhexanoate oct, and neodecanoate vers; AlR ₃ is an organoaluminum compound. They are triethylaluminum Al(C ₂ H ₅ ) ₃ , triisobutylaluminum Al(iC ₄ H ₉ ) ₃ , diisobutylaluminum hydride Al(iC ₄ H ₉ ) ₂ H; X is chlorine-containing compounds, which are diethylaluminum monochloride Al(C ₂ H ₅ ) ₂ Cl, diisobutylaluminum monochloride Al(iC ₄ H ₉ ) ₂ Cl, tert-butyl chloride tC ₄ H ₉ Cl, trimethyl Chlorosilane (CH ₃ ) ₃ SiCl; L is an electron-donating compound, they are isopropanol iC ₃ H ₇ OH, tributyl phosphate TBP; Ar is an aromatic hydrocarbon, they are benzene, toluene, ethylbenzene, cumene, di Toluene, o-xylene, m-xylene, p-xylene, mesitylene, hexamethylbenzene, vinylbenzene, divinylbenzene, naphthalene, dihydronaphthalene, tetrahydronaphthalene, anthracene, phenanthrene.

The catalyst is prepared by aging in a saturated hydrocarbon solvent at 0-50°C. The aging time is 30 minutes to 24 hours. It can be carried out in the presence of a small amount of monomer or without the presence of monomer. The components of the catalyst Molar ratio: Al/Ln ratio is 20-40, Cl/Ln ratio is 2.0-4.0, aromatics/Ln ratio is 1-500, monomer/Ln ratio is 2-10. The catalyst is suitable for the cis homopolymerization of butadiene and isoprene and the cis copolymerization of the two. The polymerization can be carried out in the presence of a solvent or without a solvent. The saturated hydrocarbon hexane is used for solution polymerization. , cyclohexane, and heptane as solvents, the monomer concentration is 8-20g/100mL, the catalyst dosage Ln/monomer ratio is 6×10 ^-7 ～1.0×10 ^-5 mol/g, and the polymerization temperature is 20-80°C , the polymerization time is 1 to 4 hours; the reaction is terminated with an ethanol solution containing 1% 2,6-di-tert-butyl-p-cresol, and the polymer is precipitated in excess ethanol, washed and extruded by ethanol, at 40°C Dry under reduced pressure for 24 hours, weigh and calculate the monomer conversion rate; measure the intrinsic viscosity [η] of the polymerized product in a toluene solution at 30°C, and use [η] to characterize the molecular weight of the polymerized product; measure with infrared spectroscopy and nuclear magnetic spectrum The microstructure and composition of the product.

The present invention proposes the following examples as further illustrations:

Example 1:

Add 4.0 mL of toluene, 1.0 mL of 0.25 mol/L Nd(naph) ₃ hexane solution, and 2.5 mL of 0.25 mol/L Al(iC ₄ H ₉ ) ₂ Cl to a dry 15 mL catalyst preparation tube under nitrogen protection Hexane solution, 2.5mL 3.0mol/L Al(iC ₄ H ₉ ) ₃ hexane solution, [Nd]=2.5×10 ^-5 mol/mL, the molar ratio of Nd/Al/Cl/toluene is 1.0 /30/2.5/150, aged at 20°C for 30 minutes for polymerization.

Under nitrogen protection, 80 mL of hexane, 20 mL of isoprene, and 1.0 mL of catalyst solution were added to an approximately 150 mL dry deoxygenated polymerization bottle. At this time, the monomer concentration was 13.6/100 mL, and the Nd/isoprene ratio was 1.8×10 ^-6 mol/g. After reacting in a constant temperature water bath at 50°C for 4 hours, stop the polymerization with 2 mL of ethanol solution containing 1.0% 2,6-di-tert-butyl-p-cresol, then precipitate the polymer in excess ethanol, wash and extrude with ethanol , and dried under reduced pressure at 40°C for 24 hours to obtain 12.9 g of isoprene polymerization product, the conversion rate was 95%, [η] was 6.6 dL/g, and the content of the cis-1,4 chains of the product was 95.6% as determined by infrared spectroscopy .

Under the condition that other conditions are exactly the same and only the toluene is changed to hexane when preparing the catalyst, the monomer conversion rate and the [η] of the polymerization product are 60% and 8.4dL/g respectively.

Example 2:

As described in Example 1, when other conditions are exactly the same and only benzene is used to replace toluene when preparing the catalyst, the Nd/benzene ratio is 1.0/180, and the [η] of the obtained monomer conversion rate and polymerization product is 75 respectively. %, 6.4dL/g.

Example 3:

As described in Example 1, when other conditions are exactly the same and only ethylbenzene is used to replace toluene when preparing the catalyst, the ratio of Nd/ethylbenzene is 1.0/130, and the obtained monomer conversion rate and [η] of the polymerization product are respectively It was 80%, 6.9 dL/g.

Example 4:

As described in Example 1, under the situation that isopropyl benzene is used to replace toluene when other conditions are exactly the same only when preparing the catalyst, this moment Nd/cumene ratio is 1.0/115, the obtained monomer conversion rate and the [η of the polymerization product ] were 85%, 6.7dL/g, respectively.

Example 5:

As described in Example 1, when other conditions are exactly the same and only when the catalyst is prepared, o-xylene is used instead of toluene. At this time, the ratio of Nd/o-xylene is 1.0/130, and the obtained monomer conversion rate and polymerization product [η] were 90%, 6.2dL/g, respectively.

Embodiment 6:

As described in Example 1, under the situation that mesitylene is used to replace toluene when other conditions are exactly the same only when preparing the catalyst, this moment Nd/ mesitylene ratio is 1.0/115, the obtained monomer conversion rate and the [η of polymerization product ] were 68%, 7.2dL/g, respectively.

Embodiment 7:

As described in Example 1, when other conditions are exactly the same and only the catalyst is prepared, 4.0 mL of 5.62 mol/L vinyl benzene hexane solution is used instead of toluene. At this time, the Nd/vinyl benzene ratio is 1.0/90, and the obtained single The volume conversion rate and the [η] of the polymerization product were 86% and 7.0dL/g, respectively.

Embodiment 8:

As described in Example 1, when other conditions are exactly the same and only the catalyst is prepared, 4.0mL3.12mol/L divinylbenzene hexane solution is used instead of toluene. At this time, the Nd/divinylbenzene ratio is 1.0/50, The obtained monomer conversion rate and [η] of the polymerized product were 70% and 6.8 dL/g, respectively.

Embodiment 9:

Add 1.0 mL of 0.25 mol/L hexamethylbenzene hexane solution, 1.0 mL of 0.25 mol/L Nd(naph) ₃ hexane solution, 2.5 mL of 0.25 mol/L Al (iC ₄ H ₉ ) ₂ Cl hexane solution, 2.5 mL of 3.0 mol/L Al(iC ₄ H ₉ ) ₃ hexane solution, and 3.0 mL of hexane, at this time [Nd]=2.5×10 ^-5 mol /mL, the ratio of Nd/Al/Cl/hexamethylbenzene is 1.0/30/2.5/1.0, and it is used for polymerization after aging at 50°C for 60 minutes.

Under nitrogen protection, 70 mL of hexane, 30 mL of isoprene, and 1.0 mL of catalyst solution were added to an approximately 150 mL dry deoxygenated polymerization bottle. At this time, the monomer concentration was 20 g/100 mL, and the Nd/isoprene ratio was 1.2×10 ^-6 mol/g. After reacting at 80°C for 2 hours, 16.3 g of isoprene polymerization product was obtained, the conversion rate was 81%, [η] was 5.0 dL/g, and the content of cis-1,4 chains in the product was 94.8% as determined by infrared.

When other conditions are exactly the same and only the hexamethylbenzene hexane solution is changed to hexane when preparing the catalyst, the conversion rate of the monomer and [η] of the polymerized product are 56% and 6.1dL/g respectively.

Example 10:

As described in Example 9, when other conditions are exactly the same and only the hexane solution of 1.0mL1.0mol/L naphthalene is used to replace the hexamethylbenzene hexane solution when the catalyst is prepared, the Nd/naphthalene ratio is now 1.0/4.0, and the obtained The monomer conversion rate and the [η] of the polymerization product were 75% and 3.8 dL/g, respectively.

Example 11:

As described in Example 9, when other conditions are exactly the same and only the catalyst is prepared, the hexane solution of 1.0mL2.5mol/L dihydronaphthalene is used instead of the hexamethylbenzene hexane solution, and the Nd/dihydronaphthalene ratio is 1.0 /10, the obtained monomer conversion rate and the [η] of the polymerization product are respectively 70%, 3.5dL/g.

Example 12:

As described in Example 9, when the other conditions are exactly the same and only the catalyst is prepared, the hexane solution of 1.0 mL of 5.0 mol/L tetrahydronaphthalene is used instead of the hexamethylbenzene hexane solution. At this time, the Nd/tetrahydronaphthalene ratio is 1.0 /20, the obtained monomer conversion rate and the [η] of the polymerization product are respectively 72%, 4.0dL/g.

Example 13:

As described in Example 9, when the other conditions are exactly the same and only when the catalyst is prepared, the hexane solution of 1.0mL0.50mol/L anthracene is used to replace the hexamethylbenzene hexane solution. At this time, the Nd/anthracene ratio is 1.0/2.0, and the obtained The monomer conversion rate and [η] of the polymerization product were 65% and 4.5 dL/g, respectively.

Example 14:

As described in Example 9, when other conditions are exactly the same and only the catalyst is prepared, the hexane solution of 1.0mL0.75mol/L phenanthrene is used instead of the hexamethylbenzene hexane solution. At this time, the ratio of Nd/phenanthrene is 1.0/3.0, The obtained monomer conversion rate and [η] of the polymerized product were 68% and 4.8 dL/g, respectively.

Example 15:

Add 2.5 mL of 0.30 mol/L Al(C ₂ H ₅ ) ₂ Cl cyclohexane solution and 2.5 mL of 3.0 mol/L Al(iC ₄ H ₉ ) ₂ H cyclohexane to the catalyst preparation tube under nitrogen protection. alkane solution, 1.0mL 0.25mol/L Nd(oct) ₃ cyclohexane solution, 4.0mL m-xylene, at this time [Nd]=2.5×10 ^-5 mol/mL, Nd/Al/Cl/m- The ratio of xylene is 1.0/30/3.0/130, aged at 0°C for 2 hours before use.

Under the protection of nitrogen, 50 mL of isoprene and 2.0 mL of catalyst solution were sequentially added into an approximately 80 mL polymerization bottle, and the Nd/isoprene ratio was 1.5×10 ^-6 mol/g. After reacting at 20°C for 1 hour, 21.1 g of isoprene polymerization product was obtained, the conversion rate was 62%, and [η] was 3.2 dL/g.

When other conditions are exactly the same and only m-xylene is changed to cyclohexane when preparing the catalyst, the monomer conversion rate and the [η] of the polymerized product are 45% and 5.4dL/g respectively.

Example 16:

Rare earth catalyst solutions were prepared as described in Example 15. Under the protection of nitrogen, add a cyclohexane solution containing 8g of butadiene, 2g of isoprene and a certain amount of cyclohexane in sequence to a 150mL polymerization bottle, so that the total monomer concentration reaches 10g/100mL, and then add 0.8 mL of catalyst solution, the Nd/monomer ratio is 2.0×10 ^-6 mol/g. After polymerizing at 50°C for 2 hours, 7.3 g of butadiene-isoprene copolymerization product was obtained, the conversion rate was 73.0%, and [η] was 5.2 dL/g. The product was determined to be butadiene It is a random copolymer of alkene and isoprene, and the cis-1,4 contents of the two monomer chains are 97.6% and 95.3% respectively.

Under the condition that other conditions are exactly the same except that m-xylene is changed to cyclohexane when preparing the catalyst, the conversion rate of the monomer and [η] of the polymerized product are 64% and 7.3dL/g respectively.

Example 17:

Add 4.0mL of 0.25mol/L tC ₄ H ₉ Cl heptane solution, 2.5mL of 3.0mol/L Al(C ₂ H ₅ ) ₃ heptane solution, 1.0mL of 0.25mol /L Nd(vers) ₃ heptane solution, 2.5mL toluene, at this time [Nd]=2.5×10 ^-5 mol/mL, the ratio of Nd/Al/Cl/toluene is 1.0/30/4.0/94, in After aging for 60 minutes at 20°C, it is ready for use.

Add 100mL of heptane solution containing 10g of butadiene and 0.24mL of catalyst solution into a 150mL polymerization bottle under nitrogen protection. At this time, the monomer concentration is 10g/100mL, and the Nd/butadiene ratio is 6×10 ^-7 mol/g. After reacting at 50°C for 3 hours, 8.0 g of butadiene polymerization product was obtained, the conversion rate was 80%, [η] was 7.0 dL/g, and the content of cis-1,4 chains in the product was 96.8% as measured by infrared spectroscopy.

Under the condition that other conditions are exactly the same and only the toluene is changed to heptane when preparing the catalyst, the monomer conversion rate and the [η] of the polymerization product are 62% and 9.4dL/g respectively.

Example 18:

Add 2.5 mL of 0.20 mol/L (CH ₃ ) ₃ SiCl heptane solution, 2.5 mL of 3.0 mol/L Al(iC ₄ H ₉ ) ₂ H heptane solution, 1.0 mL0.25mol/L Nd(vers) ₃ heptane solution, 4.0mL p-xylene, at this time [Nd]=2.5×10 ^-5 mol/mL, the ratio of Nd/Al/Cl/p-xylene is 1.0/30/2.0/130, aged at 20°C for 60 minutes before use.

Add 100mL of heptane solution containing 10g of butadiene and 0.40mL of catalyst solution to a 150mL polymerization bottle under nitrogen protection. At this time, the monomer concentration is 10g/100mL, and the Nd/butadiene ratio is 1.0×10 ^-6 mol/g. React at 50°C for 3 hours to obtain 8.5 g of butadiene polymerization product with a conversion rate of 85% and [η] of 2.6 dL/g.

Under the condition that other conditions are exactly the same except that p-xylene is changed to heptane when preparing the catalyst, the monomer conversion rate and the [η] of the polymerized product are 70% and 4.4dL/g respectively.

Example 19:

Under the protection of nitrogen, add 0.108g PrCl ₃ ·3 (iC ₃ H ₇ OH), 1.7mL1.48mol/L butadiene heptane solution, 6.6mL toluene, 1.7mL6.0mol/L A1( C ₂ H ₅ ) ₃ heptane solution, add 2.5mL of heptane to make [Pr]=2.0×10 ^-5 mol/mL, the ratio of Pr/Al/butadiene/toluene is 1.0/40/10/250 , aged at 20°C for 24 hours before use.

Add 100 mL of heptane solution containing 8.0 g of butadiene and 0.60 mL of catalyst solution into a 150 mL polymerization bottle under nitrogen protection, and the ratio of Pr/butadiene is 1.5×10 ^-6 mol/g. Polymerized at 50°C for 4 hours to obtain 6.5 g of butadiene polymerization product with a conversion rate of 81%, [η] of 9.0 dL/g, and a content of cis-1,4 chains of 98.0% as measured by infrared spectroscopy.

Under the condition that other conditions are exactly the same and only the toluene is changed to heptane when preparing the catalyst, the monomer conversion rate and the [η] of the polymerization product are 60% and 12.4dL/g respectively.

Example 20:

Add 0.262g PrCl ₃ ·3TBP, 0.34mL 1.48mol/L butadiene heptane solution, 11.2mL benzene, 0.84mL 6.0mol/L Al(C ₂ H ₅ ) ₃ to the catalyst preparation tube in sequence Heptane solution, at this time [Pr]=2.0×10 ^-5 mol/mL, the ratio of Pr/Al/butadiene/benzene is 1.0/20/2/500, aged at 20°C for 24 hours before use. Carry out the polymerization reaction of butadiene according to the conditions described in Example 19 to obtain 6.3 g of butadiene polymerization product with a conversion rate of 79% and [η] of 8.2 dL/g.

Under the condition that other conditions are exactly the same except that benzene is changed to heptane when preparing the catalyst, the monomer conversion rate and the [η] of the polymerization product are 56% and 11.8dL/g respectively.

Claims (2)

1. An improved rare earth catalyst for diolefin polymerization of aromatic hydrocarbons, characterized in that it consists of a rare earth compound catalyst system represented by LnA ₃ -AlR ₃ -X-Ar and a rare earth chloride catalyst represented by LnCl ₃ 3L-AlR ₃ -Ar System: Ln is a rare earth element representing La~Lu, among which neodymium and praseodymium are the most active elements; A is carboxylate, and these carboxylate are naphthenate, 2-ethylhexanoate, neodecanoate; AlR ₃ For organoaluminum compounds, they are triethylaluminum, triisobutylaluminum, diisobutylaluminum hydride; X is a chlorine-containing compound, they are monochlorodiethylaluminum, monochlorodiisobutylaluminum, tertiary Butyl chloride, trimethylchlorosilane; L is an electron-donating compound, they are isopropanol, tributyl phosphate; Ar is an aromatic hydrocarbon, they are benzene, toluene, ethylbenzene, cumene, xylene, o-di Toluene, m-xylene, p-xylene, mesitylene, hexamethylbenzene, vinylbenzene, divinylbenzene, naphthalene, dihydronaphthalene, tetrahydronaphthalene, anthracene, phenanthrene. 2. A preparation method of an aromatic hydrocarbon improved diolefin polymerization rare earth catalyst, which is characterized in that the catalyst is prepared by aging in a saturated hydrocarbon solvent at 0-50°C, and the aging time is 30 minutes to 24 hours, and can be used in a small amount of single The molar ratio of each component of the catalyst: Al/Ln ratio is 20-40, Cl/Ln ratio is 2.0-4.0, aromatics/Ln ratio is 1-500, monomer The /Ln ratio is 2-10.