RU2539655C1 - Method of obtaining cis-1,4-polyisoprene - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: described is method of obtaining cis-1,4-polyisoprene by isoprene polymerization in solution of isopentane or mixture of isopentane and isoamylenes in presence of catalytic complex. Preliminarily mixture of diisobutylaluminium hydride and triisobutylaluminium, as well as gaseous hydrogen in amount 0.5÷1.0 nm per 1 t of isoprene is introduced into isoprene solution. Catalytic complex is prepared by interaction of piperylene (B)-containing mixture of triisobutylaluminium and diisobutylaluminiumhydride (A) in toluene, with alcohol lanthanoid chloride solvate (C). Molar ratio A:B:C constitutes 12÷15):(1÷2):1. Alcohol lanthanoid chloride solvate is added to preliminarily cooled to - 15÷-5°C piperylene-containing mixture of triisobutylaluminium and diisobutylaluminiumhydride in toluene. Reaction mixture is exposed at temperature 10-50°C for not less than 10 hours. Isoprene polymerisation is carried out with isoprene concentration in solution 12÷17 wt % at temperature 8÷70°C until 70÷90% conversion of isoprene is achieved.

EFFECT: obtaining cis-1,4-polyisoprene with specified Mooney viscosity.

4 cl, 2 tbl, 1 ex

Description

The invention relates to the field of synthetic rubber and can be used in the petrochemical industry.

A known method of producing cis-1,4-polyisoprene [patent RU 2366667, class. C08F 136/08, publ. 09/10/2009] polymerization of isoprene in a solution of isopentane or a mixture of isopentane and isoamylenes at a temperature of 20-60 ° C and the content of isoprene in a solution of 10-20 wt.%, Under the action of a catalytic complex, pre-formed for 2-24 hours in a mixture of aliphatic and aromatic hydrocarbons by reacting a neodymium compound of tris [bis (2-ethylhexyl) phosphate] or neodymium neodecanoate with catalyst components including an alkylating agent of triisobutylaluminum (TIBA) or diisobutylaluminum Drid (DIBAG), a halogen donor representing ethyl aluminum sesquichloride or diethyl aluminum chloride, a conjugated diene representing piperylene, isoprene or butadiene, when added to the neodymium compound in any sequence with a molar ratio of neodymium: alkylating agent: halogen donor: 1 copolymer: 1 , 8-20: 2-3: 8-25, followed by deactivation by the introduction of an amine or phenolic type stabilizer in an alcohol-hydrocarbon solution, aqueous degassing and drying, while the catalytic complex additionally contains many goatomic alcohol selected from the group: ethanediol, 1,2-propanediol, 1,2,3-propanetriol - with a molar ratio of polyhydric alcohol: neodymium 0.1-1: 1.

The disadvantage of this method is the need to use to obtain a catalytic complex of an additional organoaluminum compound - a donor of a halogen of ethyl aluminum sesquichloride or diethyl aluminum chloride, which complicates the technology and leads to an increase in the cost of cis-1,4-polyisoprene.

A known method of producing cis-1,4- (co) polymers of conjugated dienes [patent RU 2203289, class. C08F 36/06, C08F 36/06, C08F 236/06, C08F 4/44, publ. 04/07/2003] the polymerization of conjugated dienes or their copolymerization among themselves in a hydrocarbon solvent in the presence of a catalytic complex consisting of a compound of lanthanides A with serial number 57-71 of the Periodic system of elements Mendeleev, organoaluminum compound B, conjugated diene C and a halogen source D, wherein the catalytic complex is formed by introducing into the hydrocarbon solution of conjugated diene C, taken in an amount of 5-35 mol per 1 mol of butadiene, a hydrocarbon solution of a halogen-free organoaluminum compound B, aged the resulting mixture for 5-15 minutes, the introduction of a hydrocarbon solution of the compound of lanthanides A selected from the group including carboxylates, alcoholates and hydrocarbon-soluble halogenide complexes , with a molar ratio of B: A = 3.1-6.0: 1 and a temperature of 20-50 ° C, holding for 2-24 hours, activating the complex by feeding DIBAG at a molar ratio of DIBAG: A = 1.1-2, 0 and holding for 5-15 minutes, followed by interaction with a halogen source D at a molar ratio D: A = 1.1-10.0 and a contact time of 5-60 minutes, followed by feeding the resulting soluble catalytic complex to a hydrocarbon solution of monomers conjugated dienes into which halogen-free organoaluminum compound B is preliminarily introduced in a general molar ratio B: A = 5-100: 1 and additionally DIBAG at a molar ratio of A: DIBAG = 1: 2-10. Butadiene, isoprene, 1,3-pentadiene or mixtures thereof in any ratio are used as conjugated dienes. As the compound of lanthanide A, a compound selected from the group is used: neodymium neodecanoate, neodymium naphthenate, neodymium octanoate, neodymium-2,2-diethylhexanoate, neodymium-2,2-diethylheptanoate, praseodymium neodecanoate, praseodymium naphthenate, praseodymium octanoate, 2 praseodymium 2-diethylhexanoate, praseodymium-2,2-diethylheptanoate, neodecanoatedime, didyme naphthenate, octanoatedime, didim-2,2-diethylhexanoate, didime-2,2-diethylheptanoate. The halogen-free organoaluminum compound B is selected from the group of compounds comprising triethylaluminum, triisobutylaluminum, diisobutylaluminum hydride, methyl, ethyl, isobutylaluminoxane, or mixtures thereof. As a source of halogen D, a compound is selected from the group consisting of diethylaluminium chloride, ethylaluminium sesquichloride, ethyl aluminum dichloride, diisobutyl aluminum chloride, isobutylaluminium dichloride, trilomide, trimethylsilane, trimethylmethylbromide, trimethylmethylbromide, trilane The method allows to obtain a polymer with a narrow molecular weight distribution.

The disadvantage of this method is that high conversion (89-99%) is achieved within 2-6 hours, and the maximum yield is not more than 327.4 kg / g-at of lanthanide in 1 hour. In addition, the need to use an additional organoaluminum compound - a halogen donor, complicates the technology, as well as the high content of the sum of organoaluminum compounds in the catalyst composition (molar ratio of lanthanide: organoaluminum compound up to 1: 100) increases the cost of cis-1,4-polyisoprene.

The closest in technical essence is a method for producing cis-1,4-polyisoprene [patent RU 2091400, cl. C08F 136/08, C08F 2/38, publ. 09/27/1997], polymerization of isoprene in a hydrocarbon aliphatic solvent in the presence of a catalyst, which is a complex comprising triisobutylaluminum or diisobutylaluminum hydride, a chlorine-containing coordination compound of an lanthanide having an atomic number from 57 to 60 with an organic ligand and a conjugated diene, into in addition to the catalyst, triisobutylaluminum or diisobutylaluminum hydride is introduced in addition to the catalyst at a molar ratio to co lanthanide unity from 1: 1 to 30: 1, moreover, alcohol or tributyl phosphate are used as the organic ligand, and piperylene is used as the conjugated diene.

The disadvantage of this method is the difficulty of ensuring the molecular weight of cis-1,4-polysoprene within the specified values, because part of the regulator is spent on the decontamination of impurities supplied with the raw materials used (monomer and solvent), as well as a high consumption of organoaluminum compounds (molar ratio of neodymium: organoaluminum compound to 1:40), which contributes to a cost increase in the cost of the resulting product.

The purpose of the invention is to obtain cis-1,4-polyisoprene with a given Mooney viscosity.

This goal is achieved in that the polymerization of isoprene in a solution of isopentane or a mixture of isopentane with isoamylenes is carried out continuously in a polymerisation battery in the presence of a catalytic complex comprising an organoaluminum compound, a solvate of lanthanide chloride and piperylene. The viscosity of the resulting 1,4-cis-polyisoprene is adjusted by changing the supply of a mixture of diisobutylaluminum hydride and triisobutylaluminum to the isoprene solution in the range from 10 to 50 g / m ³ of isoprene diisobutylaluminum hydride and hydrogen gas in an amount of 0.5-1.0 nm ³ per 1 t of isoprene. The introduction of hydrogen gas reduces the consumption of a mixture of diisobutylaluminum hydride and triisobutylaluminum, which reduces the cost of obtaining 1,4-cis-polyisoprene.

The catalytic complex is prepared by reacting a mixture of triisobutylaluminum with diisobutylaluminum hydride (A) containing piperylene (B) with a water-alcohol solvate of lanthanide chloride (C) in a molar ratio of A: B: C equal to (12-15) :( 1-2): 1, by adding the lanthanide solvate (C) to a mixture of organoaluminum compounds with piperylene (A + B) pre-cooled to - (15 ÷ 5) ° C. The addition of catalyst components in this order allows the preparation of a highly active catalyst at a temperature of from -15 ° C to -5 ° C at a high speed without local overheating of the reaction mass due to the significantly larger amount of a cooled solution of a mixture of organoaluminum compounds with piperylene relative to the amount of lanthanide chloride solvate introduced .

To prepare the catalyst, a water-alcohol solvate of lanthanide chloride of the general formula LnCl ₃ · pROH · fH ₂ O, where p = 2.2–2.8, f = 0.8–1.2, ROH-isopropanol, normal butanol, cyclohexanol or mixtures thereof, is used in the form of suspensions with a concentration of Ln 4 ÷ 12% in hexane, or in isopentane, or in the fraction of liquid paraffins with a boiling point of 220 ÷ 250 ° C, or in a mixture of the specified fraction of liquid paraffins with toluene. As the alcohol solvate of the lanthanide, water-alcohol solvates of neodymium chloride or a mixture of water-alcohol solvates of neodymium chloride and praseodymium are used.

After mixing the catalyst components, the reaction mixture is maintained at a temperature of 10 ÷ 50 ° C for at least 10 hours. Isoprene polymerization is carried out at a concentration of isoprene in the solution of 12 ÷ 17%, the temperature of the solution supplied to the polymerization, from minus 5 ° C to plus 5 ° C by feeding the catalyst in an amount that provides the temperature of the polymerizate in the range from 8 ° C to 70 ° C and conversion isoprene 70 ÷ 90%, after which the catalytic complex is deactivated with water, the polymer is stabilized by introducing an amine or phenolic type stabilizer in a hydrocarbon solution, and 1,4-cis-polyisoprene is isolated by water degassing and drying.

The feasibility of the selected limits of the process indicators is shown in example 1 and in tables 1 and 2.

Example 1. To prepare a catalytic complex, a mixture of TIBA (1008.4 kg or 5.093 kmol) and DIBAG (36.2 kg or 0.254 kmol) and 8360 kg of toluene are introduced into a reactor equipped with a mixing device and a jacket. The concentration of the mixture of TIBA and DIBAG in toluene is 0.51 mol / l, and the molar ratio of TIBA: DIBAG in the mixture is 1: 0.05. 54.6 kg of piperylene (B, 0.8 kmol) are introduced into the mixture of DIBAG and TIBA (A, the sum of moles of organoaluminum compounds 5.347 kmol) in toluene. The reagent solution in toluene is cooled to a temperature of minus 10 ° C, 647 kg of a suspension of a water-alcohol solvate of neodymium chloride (C, 0.401 kmol) are introduced into the fraction of liquid paraffins with a boiling point of 220 ÷ 250 ° C with stirring. The input rate of the suspension of the alcohol solvate of neodymium chloride is maintained such that the temperature of the reaction mixture is not more than minus 5 ° C. The molar ratio of the components A: B: C is 13.3: 2: 1. Next, the temperature of the reaction mixture is gradually increased to 23 ° C and maintained at this temperature for 24 hours to obtain a catalytic complex.

The process of producing cis-1,4-polyisoprene is carried out in a polymerization battery. For polymerization serves isoprene (6.03 t / h) and a mixture of isopentane and isoamylenes (30.97 t / h), the concentration of isoprene in the solution is 16.3% wt. 6 nm ³ / h of hydrogen gas and 1.17 kg / h of a mixture of diisobutylaluminum hydride and triisobutylaluminum in toluene solution are introduced into the resulting isoprene solution. The consumption of gaseous hydrogen is 1.0 nm ³ in terms of 1 ton of isoprene. Polymerization of isoprene in a solution of a mixture of isopentane and isoamylenes in the presence of a catalytic complex is carried out in a polymerization battery at an initial temperature of 18 ° C to a final temperature of 60 ° C. Isoprene conversion 76%. Next, the reaction mixture is deactivated and washed with water, stabilized with an antioxidant. Cis-1,4-polyisoprene is isolated by water degassing and dried. Obtain 4.66 t / h of the target product with a Mooney viscosity of 79 units.

The process of preparing the catalytic complex by the interaction of a mixture of diisobutylaluminum hydride with triisobutylaluminum (A) in toluene containing piperylene (B) with an alcohol solvate of lanthanide chloride (C) in a molar ratio of A: B: C equal to (12-15) :( 1-2-15) :( 1-2 ): 1, by adding an alcohol solvate of lanthanide chloride to a mixture of diisobutylaluminium hydride with triisobutylaluminum in a toluene containing piperylene pre-cooled to -15 ÷ -5 ° C, keeping the reaction mixture at a temperature of 10-50 ° C for at least 10 hours ensures a high act the purity of the resulting catalytic system, allowing to obtain cis-1,4-polyisoprene having the desired Mooney viscosity in the range 55 ÷ 90 units (Table 1).

Carrying out the polymerization process at a concentration of isoprene in a solution of 12 ÷ 17% wt. at a temperature of 8 ÷ 70 ° C until the conversion of isoprene to 70 ÷ 90% and the introduction of gaseous hydrogen in an amount of 0.5-1.0 nm ³ in terms of 1 ton of isoprene provides the target product of the required quality (table 2).

Table 1 The influence of the preparation conditions of the catalytic complex on the properties of the catalyst, the Mooney viscosity of 1,4-cis-polyisoprene and technical and economic indicators of the process Experience number A: B: C ratio (mol) The ratio of CHIBA: DIBAG (mol) The concentration of the mixture TIBA and DIBAG in solution,
mol / l The mixing temperature of the solvate of neodymium chloride,
° C The temperature of the reaction mixture,
° C Duration of exposure, h Note one 13.3: 2: 1 1: 0.05 0.51 -5 23 24 High catalyst activity 2 11.0: 2: 1 1: 0.05 0.5 -10 23 24 The decrease in catalyst activity, the degree of conversion 3 17.0: 2: 1 1: 0.05 0.5 -10 23 24 AOS overspending four 13.0: 0.8: 1 1: 0.05 0.5 -10 23 24 The decrease in catalyst activity, the degree of conversion 5 13.0: 2.5: 1 1: 0.05 0.5 -10 23 24 Reduced catalyst fluidity during long-term storage without stirring 6 15.6: 2.9: 1 1: 0.05 0.5 -10 23 24 Overuse of AOS, reduction in catalyst fluidity during prolonged storage without stirring 7 13.0: 2: 1 1: 0.70 0.5 -10 23 24 Increasing the activity of the catalyst, increasing the rate of maturation of the catalyst, reducing the consumption of AOS to obtain a product with a given Mooney viscosity 8 13.0: 2: 1 1: 0.30 0.2 -10 23 24 Catalyst activity reduction 9 13.0: 2: 1 1: 0.30 0.7 -10 23 24 Catalytic dosage difficulty
complex in the polymerization process 10 13.0: 2: 1 1: 0.30 0.5 +2 23 24 Reduced catalyst activity, isoprene conversion eleven 13.0: 2: 1 1: 0.30 0.5 -eighteen 23 24 Energy overrun for cooling and subsequent heating 12 13.0: 2: 1 1: 0.30 0.5 -10 5 24 Catalyst activity reduction 13 13.0: 2: 1 1: 0.30 0.5 -10 55 24 Catalyst activity reduction fourteen 13.0: 2: 1 1: 0.30 0.5 -10 23 8 Catalyst activity reduction

table 2 The influence of the parameters of the polymerization process on the Mooney viscosity of 1,4-cis-polyisoprene and the technical and economic parameters of the polymerization process at equal flow rates of the polyisoprene solution using catalysts of composition A: B: C = 13: 2: 1, prepared at minus 10 ° C holding at 23 ° C for 30 hours Experience number The concentration of isoprene in solution,% DIBAG consumption in isoprene solution, g / m ³ The consumption of hydrogen, m ³ / t of isoprene Polymerization temperature, start / end, ° C Mooney Polyisoprene Viscosity The conversion of isoprene,% Note one 16.3 13 1,0 15/60 79 78 The optimal combination of product yield, DIBAG, toluene, hydrogen and rubber properties 2 11.0 13 1,0 10/55 79 90 Lower product yield 3 18.0 13 1,0 15/60 79 60 Lower product yield four 15.0 13 0.4 15/60 81 78 Mooney viscosity increase of polyisoprene 5 15.0 eighteen 0.4 15/60 79 82 Increased consumption of DIBAG, toluene 6 15.0 eighteen 1,0 15/60 76 82 Increased product yield, reduced Mooney viscosity 7 15.0 eighteen 1.4 15/60 76 82 Unproductive consumption of hydrogen due to its limited solubility in isoprene solution 8 15.0 23 1,0 10/55 72 67 Reduced Isoprene Conversion 9 15.0 27 1,0 24/75 68 80 Undesirable change in the microstructure of polyisoprene

Using the proposed method for producing cis-1,4-polyisoprene in the claimed ranges of process indicators in the aggregate, it is possible to obtain the target product with the desired Mooney viscosity (MB 1 + 4, 100 ° C) within 55 ÷ 90 units.

Claims (4)

1. The method of producing cis-1,4-polyisoprene by polymerization of isoprene in a solution of isopentane or a mixture of isopentane and isoamylenes in the presence of a catalytic complex based on a compound of lanthanide, including an organoaluminum compound, lanthanide chloride and piperylene, with the preliminary introduction of triisobutylaluminum or diisobutylaluminium ishydride the fact that a mixture of diisobutylaluminum hydride and triisobutylaluminum, as well as a gas hydrogen in an amount of 0.5 ÷ 1.0 nm ³ per 1 ton of isoprene, and the catalytic complex is prepared by reacting a mixture of diisobutylaluminum hydride with triisobutylaluminum (A) in toluene containing piperylene (B) with an alcohol solvate of lanthanide chloride (C) in a molar ratio A: B: C, equal to (12 ÷ 15) :( 1 ÷ 2): 1, by adding the alcohol solvate of lanthanide chloride to a mixture of diisobutylaluminium hydride with triisobutylaluminum and piperylene previously cooled to -15 ÷ -5 ° C, keeping the reaction mixture at temperature 10 ÷ 50 ° C for at least 10 hours, polymerization rovodyat isoprene at a concentration in solution 12 ÷ 17% by weight. at a temperature of 8 ÷ 70 ° C until the conversion of isoprene to 70 ÷ 90%. 2. The method according to claim 1, characterized in that in the preparation of the catalytic complex, the molar ratio of triisobutylaluminum: diisobutylaluminium hydride is 1: (0.05 ÷ 0.60) at a concentration of a mixture of triisobutylaluminum and diisobutylaluminum hydride in toluene 0.3 ÷ 0.6 mol / l 3. The method according to claim 1, characterized in that as the alcohol solvate of the lanthanide chloride, suspensions of a water-alcohol solvate of neodymium chloride or a mixture of water-alcohol solvates of neodymium and praseodymium chlorides in hexane, isopentane, a fraction of liquid paraffins with a boiling point of 220 ÷ 250 are used ° C or in a mixture of a fraction of liquid paraffins with toluene. 4. Cis-1,4-polyisoprene having the desired Mooney viscosity (MB 1 + 4, 100 ° C) within 55 ÷ 90 units, obtained by the method of claim 1.