RU2267355C2 - Method of preparing butadiene polymerization and butadiene-conjugated diene copolymerization catalyst - Google Patents

Abstract

FIELD: polymerization catalysts.

SUBSTANCE: catalyst preparation involves interaction of rare-earth element compound, conjugated diene, and diisobutylaluminum hydride followed by ageing of reaction mixture for 10-30 min, adding tetraisobutyl-dialumoxane and alkylaluminum hydroxide at molar ratio 1:(2-20):(3-12):(6-12):(1.5-3), respectively, and ageing resulting mixture for 10-15 h. Diene utilized is in the process is pyperilene or isoprene and rare-earth element compound is rare-earth element carboxylate or alcoholate. Catalyst can, in particular, find use in production of cis-1,4-polydienes.

EFFECT: achieved preparation of high-efficiency catalyst enabling production of highly stereospecific polybutadiene or butadiene/isoprene or butadiene/pyperilene copolymers at narrower molecular mass distribution.

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Description

The invention relates to methods for producing a catalyst for the polymerization of butadiene and copolymerization of butadiene with conjugated dienes and may find application in the synthetic rubber industry in the production of cis-1,4-polydienes.

A known method of producing a catalyst for the polymerization of conjugated dienes by the interaction of alkylaluminoxane, previously synthesized by the reaction of trialkylaluminum with water with constant stirring and a temperature of -5 ÷ -10 ° C and a molar ratio of aluminum: water, equal to 2: 1, with piperylene and solvate of lanthanide chloride (RF Patent 2061546 , C 08 F 136/08, priority 10/19/94). The interaction of alkylaluminoxane with a neodymium compound is carried out at a temperature not exceeding -5 ° C, then the reaction mass is heated to room temperature and held for 6-15 hours. The molar ratio of neodymium: aluminum: piperylene is 1: 10 ÷ 20: 18 ÷ 25. When using a catalyst containing a solvate of neodymium chloride, piperylene and aluminoxane for the polymerization of isoprene, the polymer yield is 402 kg / g-at Nd per hour. The polymer has a high intrinsic viscosity of 8.5 dl / g and a low molecular weight distribution width M _w / M _{n of} 2.1. The content of cis-1.4 units is 98.4%. The intrinsic viscosity can be reduced by introducing diisobutylaluminum hydride into the monomer solution prior to feeding the catalyst. As a result of this, a polymer with a characteristic viscosity of 4.6-5.8 dl / g and a value of M _w / M _{n of} 2.4-2.8 is obtained. However, the polymer yield is 350 kg / g-at of lanthanide per hour.

The disadvantages of the method are the use of a lanthanide chloride solvate insoluble in hydrocarbons for the preparation of the catalyst and the need to mix the components at sub-zero temperatures. This complicates the preparation of the catalyst. In addition, according to the authors of this application, when using such a catalyst for the polymerization of butadiene or the copolymerization of butadiene with isoprene, polymers with a very high intrinsic viscosity (more than 10 dl / g) are formed, which complicates the processing of the polymer. The decrease in viscosity due to the introduction of diisobutylaluminium hydride into the solution results in polybutadiene with a viscosity of 3.5-5.0 dl / g. However, the value of M _w / M _n in this case is 10-14.

A known method of producing a catalyst for the polymerization of conjugated dienes by the interaction of hydrocarbon-soluble neodymium carboxylate or alcoholate and methylaluminoxane (g.Ricci, S. Jtalia, C. Komani, Polym. Commun, 1991, No. 32, No. 17, p. 514-517). The components of the catalyst are introduced directly into the monomer solution.

The disadvantage of this method is the very low activity of the catalyst - the polymer yield is 0.5-1.4 kg / g-at Nd. The content of cis-1.4 units in polybutadiene is 87.6-94.4%. M _w / M _n (according to the authors of this application) is ~ 15.

Closest to the proposed technical solution, the technical essence is a method of producing a catalyst for the polymerization of butadiene or its copolymerization with isoprene by reacting in a hydrocarbon solvent a carboxylate compound of a rare-earth element with an alkylaluminum halide, a conjugated diene and a mixture of diisobutylaluminum hydride and the same tetraalkane : 1 ÷ 5: 5 ÷ 60: 0.5 ÷ 20: 0.01 ÷ 39 (RF Patent 2087488, С 08 F 136/06, priority 16.03.94).

However, the catalyst obtained in this way is not sufficiently active. The polymer yield per hour is 488 kg / g-at REE at a polymerization temperature of 50 ° C (example 7 of the description of the invention). In addition, according to the authors of this application, the polymer has a wide molecular weight distribution — M _w / M _n is 10.

The objective of the proposed technical solution is to develop a method for producing a catalyst for the polymerization of butadiene and copolymerization of butadiene with conjugated dienes, which has high activity and allows to obtain a highly stereoregular polymer with a narrower molecular weight distribution.

This object is achieved in that in the inventive method for producing a catalyst for the polymerization of butadiene and copolymerization of butadiene with conjugated dienes by the interaction of components including a compound of a rare earth element, diisobutylaluminium hydride, tetraalkyl dialumoxane, alkylaluminium halide and a conjugated diene, first the mixture of DI over a period of 10-30 minutes, and then tetraalkyldiallyumoxane and alkylaluminium halide are added.

The process is carried out with stirring in an atmosphere of inert gas (argon) and ambient temperature. The molar ratio of REE: DIBAG: tetraalkyldiallyumoxane: alkylaluminum halide (according to Cl): conjugated diene is 1: 3 ÷ 12: 6 ÷ 12: 1,5 ÷ 3: 2 ÷ 20.

The components of the catalyst, with the exception of the conjugated diene, are introduced as a solution in a hydrocarbon solvent. Aliphatic (e.g., benzyl), aromatic (e.g., toluene), or cycloaliphatic (e.g., cyclohexane) hydrocarbons may be used as a solvent.

As a rare-earth element compound, carboxylates or alcoholates formed by an individual lanthanide - neodymium (TU 48-4-186-72) or a technical mixture of rare-earth metals, the so-called didim, containing at least 85% neodymium and praseodymium from the sum of all incoming metals (TU) are used HELL 11.46-89) and acids, for example naphthenic, α- and α, α '-branched monocarboxylic (TU 2431-200-00203312-2000).

As tetraalkyldiallyumoxane, tetraisobutyldiallyumoxane (TIBAO) is used.

As the alkylaluminum halide, isobutylaluminium sesquichloride (IBACC), isobutylaluminium dichloride (IBADC), diisobutylaluminium chloride (DIBAC) are used.

Piperylene (TU 38.103300-83) or isoprene (TU 38.103653-88) are used as the conjugated diene.

Alkylaluminium halide and TIBAO are administered in any order. After mixing all the components of the catalyst, the mixture is incubated for 10-15 hours and used for (co) polymerization.

(Co) polymerization is carried out at a temperature of 0-80 ° C, preferably 30-60 ° C, in an organic solvent, for example heptane, toluene, cyclohexane or a mixture of isoamylenes.

The activity of the catalyst is estimated in kg of polymer obtained per 1 g-atom of rare-earth element for 1 hour

Butadiene or its mixture with isoprene or piperylene is used as a monomer.

The following are examples illustrating the invention.

Example 1

In a glass reactor, previously evacuated, heated and filled with dry argon, 2 ml of a solution of neodymium carboxylate in toluene (concentration 0.15 mol / L) is loaded and 0.1 ml of piperylene and 2 ml of DIBAG in toluene are introduced at room temperature ( concentration of 1.35 mol / l). The reaction mixture was kept under stirring for 15 minutes, then 0.5 ml of a solution of IBASX in toluene (concentration of Cl-1.2 mol / L ions) and 2.7 ml of TIBAO in toluene (concentration 1.0 m / L) were added sequentially. The molar ratio of REE: DIBAG: TIBAO: IBASH (Cl): piperylene = 1: 9: 9: 2: 5.

The resulting reaction mixture was stirred for 3 hours, after which the stirring was stopped, and the mixture was kept for 10 hours and used as a catalyst.

An 80 ml glass ampoule pre-evacuated and filled with dry argon is charged with 40 ml of a solution of butadiene in heptane containing 3.25 g of butadiene. The ampoule is thermostated at 50 ° C and 0.25 ml of the catalyst solution is added via syringe. After 30 minutes, the polymer was isolated. The polymer yield is 975.5 kg / g-neodymium atom per 1 hour. Polybutaden contains 99.1% cis-1.4 units, has an intrinsic viscosity of 4.5 dl / g and a molecular weight distribution of 3.1.

Example 2

In the conditions of example 1, but using gasoline as a solvent, a mixture of 0.04 ml of piperylene, 2 ml of a solution of neodymium n-butylate (concentration 0.15 m / l) and 0.66 ml of a DIBAG solution (concentration 1.35 mol / l). The mixture is kept under stirring for 10 minutes, after which 0.37 ml of DIBAC solution (Cl-1.2 mol / L concentration of ions) and 3.6 ml of TIBAO solution (1.0 mol / L concentration) are successively introduced into it. The molar ratio of REE: DIBAG: TIBAO: DIBAC: piperylene - 1: 3: 12: 1,5: 2.

The resulting mixture was stirred for 2 hours, then stirring was stopped, and the mixture was incubated for another 13 hours and used as a catalyst.

The polymerization of butadiene is carried out under the conditions of example 1, but in cyclohexane. The polymer yield is 810 kg / g-atom of neodymium per 1 hour. Polybutadiene contains 98.9% cis-1.4 units, has an inherent viscosity of 4.8 dl / g and a molecular weight distribution of 3.7.

Example 3

Under the conditions of example 1, but using cyclohexane as a solvent, 2 ml of Didim carboxylate (concentration 0.15 mol / L), 2.64 ml of DIBAG solution (concentration 1.35 mol / L) and 0.4 ml of isoprene are mixed . The mixture is kept under stirring for 30 minutes, and then 1.8 ml of TIBAO solution (concentration 1.0 mol / L) and 0.75 ml of IBADH solution (Cl-1.2 mol / L ion concentration) are added to it. The molar ratio of REE: DIBAG: TIBAO: IBADH (Cl): isoprene = 1: 12: 6: 3: 20.

The resulting mixture was stirred for 2.5 hours, and then held without stirring for 12 hours and used as a catalyst.

The copolymerization of butadiene and isoprene in a molar ratio of 75:25, respectively, is carried out under the conditions of example 1, but in toluene. The copolymer yield is 780 kg / g-REE atom per hour.

The composition of the copolymer: 75.2 mol.% Butadiene units and 24.8 mol.% Isoprene units. The copolymer contains 98.8% cis-1.4 units, has an intrinsic viscosity of 3.9 and a molecular weight distribution of 3.7.

Example 4

In the conditions of example 1, a mixture of 2 ml of a solution of neodymium carboxylate (concentration of 0.15 mol / l), 0.2 ml of piperylene and 1.32 ml of DIBAG solution (concentration of 1.35 mol / l) are mixed. The mixture is kept under stirring for 10 minutes, and then 3 ml of TIBAO solution (concentration 1.0 mol / L) and 0.62 ml of DIBAC solution are introduced into it. The molar ratio of REE: DIBAG: TIBAO: DIBAC (Cl): piperylene = 1: 6: 10: 2.5: 10. The resulting mixture was stirred for 1 h, and then allowed to stand for another 10 h without stirring and was used as a catalyst.

The copolymerization of butadiene and piperylene in a molar ratio of 85:15, respectively, is carried out under the conditions of example 1, but in a mixture of isoamylenes.

The copolymer yield is 705 kg / g-REE atom per 1 hour. The composition of the copolymer is 85.5 mol.% Butadiene units and 14.5 mol.% Piperylene units. The content of cis-1.4 units is 98.6%. The copolymer has an intrinsic viscosity of 4.1 and a molecular weight distribution of 4.0.

Thus, the proposed method makes it possible to obtain a highly active catalyst that allows the production of highly stereoregular polybutadiene and butadiene copolymers with conjugated dienes with a much narrower molecular weight distribution.

Claims (1)

A method of producing a catalyst for the polymerization of butadiene and the copolymerization of butadiene with conjugated dienes by the interaction of components including a compound of a rare earth element, diisobutylaluminium hydride, tetraisobutyldiallyumoxane, alkylaluminium halide in the form of solutions in a hydrocarbon solvent and a conjugated diene, which is used in combination with diene the mixture is incubated for 10-30 minutes, and then tetraisobutyldial oxane and alkylaluminium halide at a molar ratio of 1: 2 ÷ 20: 3 ÷ 12: 6 ÷ 12: 1,5 ÷ 3, respectively, and maintain the mixture for 10-15 hours, with piperylene or isoprene being used as the conjugated diene, and as rare earth compounds use a rare earth carboxylate or alcoholate.