RU2127281C1 - Process for preparing cis-1,4-polybutadiene and cis-1,4- copolymer and isoprene - Google Patents

Abstract

FIELD: chemistry of polymers. SUBSTANCE: cis-1,4-polybutadiene and cis-1,4-butadiene- isoprene copolymer using Ziegler-Natt catalyst systems. Catalyst is complex preformed by reacting solvated salts of rare-earth elements (A) with organoaluminium compound (B) in the presence of conjugated diene (C) at A:B:C molar ratios of 1:(5-20):(0.5-50), and molecular weight regulator is dialkyl aluminium hydride. Polymers prepared by the claimed process have reduced plasticity and cold flow. EFFECT: more efficient preparation process. 2 cl, 1 tbl

Description

 The invention relates to a technology for producing cis-1,4-polybutadiene and cis-1,4-copolymer of butadiene and isoprene under the influence of Ziegler-Natta catalytic systems and can be used in the synthetic rubber industry, and the resulting polymers in the rubber and tire industries .

 Known methods for producing cis-1,4-polybutadiene [1] and cis-1,4-copolymer of butadiene and isoprene [2,3] under the action of catalytic systems based on compounds of rare earth elements (REE) (SU 1539199 A1, 1990; US 4429089 A, 1984; SU 94009096 A1, 1996).

 The closest in technical essence to the described invention is the method [3], according to which the polymerization of butadiene and its copolymerization with isoprene is carried out under the influence of a catalytic complex pre-formed in the presence of monomer, consisting of REE carboxylate, alkylaluminium sesquichloride and organoaluminum compound.

 The disadvantage of the prototype is that the catalytic complex based on carboxyl REE is characterized by relatively low activity, and cis-1,4-polybutadiene and its copolymer with isoprene, obtained under the influence of this catalyst, have high ductility and cold flow. High cold flow does not allow the polymer to be transported to the consumer with a sufficient degree of reliability of retaining the shape of rubber briquettes, and increased ductility requires additional energy consumption to separate it from the solution.

 In the proposed method for producing cis-1,4-polybutadiene and cis-1,4-copolymer of butadiene with isoprene, the polymerization of butadiene and its copolymerization with isoprene is carried out in a hydrocarbon solvent under the influence of a catalytic complex preformed in the presence of diene (piperylene, butadiene, isoprene), consisting of solvated salts of REE and an organoaluminum compound, and dialkylaluminum hydride is used as a molecular weight regulator, which is fed into the charge in an amount of 0.1-1.0 g / kg of monomer.

 The use of solvated salts of rare-earth elements as the main component of the catalytic complex instead of REE carboxylate at the indicated molar ratios of the components makes it possible to obtain more active catalysts in comparison with the prototype. In addition, cis-1,4-polybutadiene and cis-1,4-copolymer of butadiene with isoprene, obtained in accordance with the proposed method, have reduced ductility and cold flow, which allows to improve the presentation of the polymers and transport them to the consumer without significantly changing the shape of the briquettes .

 The essence of the proposed method and its advantages compared with the prototype (example 1) are disclosed in examples (2-4).

Example 1 (prototype). 10 ml (2.54 mol) of a toluene solution of REE carboxylate are placed in a reactor of dry nitrogen, to which 2.72 ml of isobutylaluminium sesquichloride (IBACX) solution (6.25 mmol Cl), 2.5 ml (25) are successively added with stirring. ml) of piperylene and 238 ml (50 mmol) of a toluene solution of triisobutylaluminum (TIBA) containing 25.3 wt.% (of total aluminum) diisobutylaluminium hydride (DIBAG) and 6.77 wt.% (of total aluminum) of tetraisobutyldialuminumoxane (TIBAO). The contents of the reactor are incubated for 24 hours at a temperature of 25 ^o C until complete maturation of the catalytic complex. The molar ratio of the components in the REE catalytic complex: IBASH: piperylene: TIBA = 1: 2.5 (for chlorine): 10: 20.

A suspension of the catalytic complex with a REE concentration of 0.01 mol / L is used for the polymerization of butadiene. The polymerization of butadiene is carried out in a 3-liter laboratory autoclave, where 2000 g of a mixture, which is a 10 wt.% Solution of butadiene (200 g) in toluene and 37 ml (0.37 mmol REE) of a suspension of the catalytic complex, are loaded in a stream of dry nitrogen. The process is carried out for four hours at 50 ^o C and stirring. Monomer conversion 85%.

Example 2. In a reactor, 70 ml (30 mmol) of a TIBA toluene solution containing 8.1 wt.% (Of total aluminum) DIBAG and 6.3 wt. % (of total aluminum) TIBAO, and 0.25 ml (2.5 mmol) of piperylene. The reactor contents were cooled to -10 ^o C and gradually added with stirring 3.58 ml (2.5 mmol REE) suspension didymium chloride solvate NdCl ₃ • 3iC ₃ H ₇ OH in the liquid paraffin. The contents of the reactor are kept for 24 hours at 25 ^° C. until the catalytic complex is fully matured. The molar ratio of components in the catalytic complex: REE: piperylene: TIBA = 1: 1: 12, the concentration of REE - 0,034 mol / L.

The polymerization of butadiene is carried out in a laboratory autoclave (V = 3 l), where 2000 g of a mixture of 10 wt.% Are charged in a stream of dry nitrogen. % solution of butadiene (200 g) in toluene, 5.7 ml (0.12 g) of toluene solution DIBAG (0.6 g / kg monomer) and 10.9 ml (0.37 mmol REE) of the suspension of the catalytic complex. The process is carried out for two hours at 25 ^o C. Monomer conversion 98%.

Example 3. In a reactor, 29.1 ml (12.5 mmol) of the TIBA toluene solution of the same composition as in Example 2 and 0.13 ml (1.25 mmol) of isoprene are placed in a dry nitrogen atmosphere. The reactor contents were cooled to - 10 ^o C and gradually added with stirring 3.58 ml (2.5 mmol REE) suspension didymium chloride solvate NdCl ₃ • 3iC ₃ H ₇ OH in the liquid paraffin. The contents of the reactor are kept for 24 hours at 25 ^° C. until the catalytic complex is fully matured. The molar ratio of components in the catalytic complex: REE: isoprene: TIBA = 1: 0.5: 5, the concentration of REE - 0,076 mol / L. The copolymerization of butadiene with isoprene is carried out in a 3 liter laboratory autoclave, where 2000 g of a mixture of a mixture of butadiene (197.5 g) and isoprene (2.5 g) in hexane, 9.5 ml (0, 2 g) of a toluene solution of DIBAG (1.0 g of DIBAG / kg of monomer) and 4.9 ml (0.37 mmol of REE) of a suspension of the catalytic complex. The ratio of monomers in the initial mixture of butadiene: isoprene = 99: 1 (mol.).

The process is carried out for two hours at a temperature of 25 ^o C. The conversion of monomers 96%.

Example 4. 116.3 ml (540 mmol) of the TIBA toluene solution of the same composition as in Example 2 was placed in a dry nitrogen atmosphere in the reactor. The contents were cooled to -10 ^° C, 10.9 ml (125 mmol) was added to it. butadiene and gradually, with stirring, 3.58 ml (2.5 mmol REE) suspension didymium chloride solvate NdCl ₃ • 3iC ₃ H ₇ OH in the liquid paraffin. The contents of the reactor are incubated for 24 hours at a temperature of 25 ^o C until complete maturation of the catalytic complex. The molar ratio of components in the catalytic complex: REE: butadiene: TIBA = 1:50:20, REE concentration = 0.02 mol / L.

The copolymerization of butadiene with isoprene is carried out in a 3 liter laboratory autoclave, where 2000 g of a mixture of butadiene (88.6 g) and isoprene (111.5 g) in toluene (1800 g) are charged in a stream of dry nitrogen, 0.83 ml (0.02 g) of a toluene solution of DIBAG (0.1 g of DIBAG / kg of monomer and 16.5 ml (0.33 mmol of REE) of a suspension of the catalytic complex. Monomer ratio in the initial mixture of butadiene: isoprene = 50:50 (mol. ). The process is carried out at a temperature of 25 ^o C and stirring. The conversion of monomers 98%.

 The properties of cis-1,4-polybutadiene and its copolymers with isoprene obtained in examples 1-14 are presented in the table.

 Thus, in examples 1-4 it is shown that the catalytic complex based on the solvate of chloride and the organoaluminum compound is characterized by higher activity compared to the prototype, and cis-1,4-polybutadiene and its copolymer with isoprene, obtained in accordance with the proposed method, have reduced ductility and cold flow.

Literature
1. USSR author's certificate N 1539199, 30.01.90, C 08 F 4/42, 136/06 (analogue).

 2. US patent N 4429089, 84.01.31 (analog).

 3. The Russian patent for the application N 94-009096 / 04 (009071) dated 03.16.94 (prototype).

Claims (1)

 The method of producing cis-1,4-polybutadiene and cis-1,4-copolymer of butadiene and isoprene by polymerization of butadiene or its copolymerization with isoprene in a hydrocarbon solvent in the presence of a Ziegler-Natta catalyst, characterized in that the complex is preformed as a catalyst by reacting the solvated salts of rare-earth elements (A) with an organoaluminum compound (B), which is a mixture of trialkylaluminum, dialkylaluminum hydride and tetraalkyldiallyumoxane, in the presence of conjugated diene (C) with the following molar ratio of components = A: B: C = 1: (5 - 20): (0.5 - 50), and dialkylaluminium hydride is used as a regulator of the molecular weight, which is fed into the charge in an amount of 0 , 1 - 1.0 g / kg of monomer.

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