RU2447055C1 - Method of producing polymers containing cyclopropane groups - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing polymers with substituted cyclopropane groups in the backbone chain or side chains of general formula (1):

. The method involves reaction of 1,2-polybutadiene with alkyldiazoacetate in the medium of an organic solvent in the presence of a catalyst. The catalyst used is copper (II) triflate - Cu(OTf)₂, with molar ratio 1,2-polybutadiene: alkyldiazoacetate: catalyst equal to 1:0.5-1:0.01.

EFFECT: obtaining polymer products (1) with higher degree of functionalisation (conversion of unsaturated links to cyclopropane groups), with different molecular weight, which can be intentionally varied in a wide range of values.

3 cl, 7 ex, 1 tbl

Description

The invention relates to the field of macromolecular compounds, in particular to the production of polymer products containing alkoxycarbonyl substituted cyclopropane groups in the composition of macromolecules, of the general formula (1):

These polymer products are copolymers containing alkoxycarbonyl-substituted cyclopropane groups in the side units (b) and in the main chain (d) of the macromolecules, as well as carbon-carbon double bonds in the side units (a) and in the main chain (c) [unit ratio (a + b) :( c + d) = 60-95: 5-40]. Polymer products (1) are characterized by a high complex of physicomechanical properties, good adhesive properties and can be used in adhesive compositions, sealants, paints and coatings, as modifiers in various compositions of thermoplastics and elastomers.

Polymer products (1) can be obtained by chemical modification of 1,2-polybutadiene of a certain composition and structure, containing 1,2- and 1,4-polymerizations of 1,3-butadiene in the composition of macromolecules, which are synthesized in industry by 1,3- butadiene on complex catalysts (RF patent No. 2072362, RF patent No. 2177008, RF application No. 2005104832, US patent No. 4182813, RF patent No. 2139299).

The method for producing polymers of formula (1) is based on the interaction of unsaturated bonds of 1,2-polybutadiene with alkoxycarbonylcarbene generated in sity by catalytic decomposition of alkyl diazoacetate in an organic solvent with the formation of a polymer product containing alkoxycarbonyl substituted cyclopropane groups in the main chain and side units:

A known method (AS USSR No. 176065) for the preparation of polymers of formula (1), which consists in the interaction of 1,2-polybutadiene with methyldiazoacetate in the presence of a copper catalyst. The reaction is carried out in an organic solvent (cyclohexane) at a temperature of 95-100 ° C for 40 min in an inert gas medium, gradually dosing methyldiazoacetate in a polymer solution in the presence of a copper catalyst. The ratio of 1,2-polybutadiene: catalyst is 49: 1 (wt.). The resulting polymer product is separated from the catalyst and precipitated with alcohol. The degree of functionalization (conversion of unsaturated units to cyclopropane groups) of the polymer is 9.4%.

The disadvantage of this method is the low degree of functionalization of the polymer (less than 10%), as well as the reaction at a relatively high temperature.

Closest to the proposed invention is a method (V.F. Gareev, T.A. Yangirov, V.A. Kraikin, S.I. Kuznetsov, PM Sultanova, R.Z. Biglova, V.A. Dokichev // Bulletin of the University of Bashkir 2009. V.14. No. 1, pp. 36-39) for the preparation of polymers of the formula (1) based on the interaction of syndiotactic 1,2-polybutadiene with methyl diazoacetate in the presence of a catalytic system comprising copper (II) acetate, 2, 4-lutidine and zinc chloride with a molar ratio of components equal to 1: 8.6: 0.16. 1,2-Polybutadiene has a number average molecular weight M _n = 52.6 · 10 ³ , the content of 1,2- and 1,4-polymerization units in the macromolecules is 85 and 15 mol%, respectively, the degree of syndiotacticity is 53%.

The reaction is carried out in methylene chloride at a temperature of 40 ° C and a molar ratio of 1,2-polybutadiene: methyldiazoacetate: catalyst [calculated on Cu (OAc) ₂ ] equal to 1: 1: 0.01 until gas evolution ceases. After completion of the synthesis, the solvent was removed in vacuo, petroleum ether was added to the residue, and the catalyst system was separated. The product is purified by reprecipitation in a chloroform-ethanol system and dried in vacuo. The total content of functionalized units in the polymer is 12-13 mol.%.

The disadvantage of this method is the low degree of polymer functionalization (not more than 13%), as well as the use of a rather complex catalytic system. In addition, to obtain polymer products (1), it is proposed to use only 1,2-polybutadiene with a syndiotactic structure having a specific molecular weight and composition. This limits the possibilities of this method to obtain polymers with a molecular weight in the range of M _n = 52-54 · 10 ³ and a narrow set of properties. Thus, the prototype does not indicate the possibility of obtaining polymers of the formula (1) having a different composition, molecular weight, characterized not only by the syndiotactic, but also by the atactic structure of the macromolecules, i.e. with a wider range of properties.

The technical task of this invention is to develop a method for producing polymer products (1), characterized in comparison with the polymer described in the prototype:

- a higher degree of functionalization (conversion of unsaturated units into cyclopropane groups);

- having a different molecular weight, which can be purposefully changed in a wide range of values (depending on the requirements for the polymer product).

The specified technical problem is achieved by the fact that in the interaction of 1,2-polybutadiene with methyldiazoacetate in the presence of an organic solvent in the presence of a catalyst at a molar ratio of 1,2-polybutadiene: alkyl diazoacetate: catalyst 1: 0.5-1: 0.01, as a catalyst copper (II) triflate is used - Cu (OTf) ₂ , and 1,2-polybutadiene a, of atactic or syndiotactic structure with a degree of syndiotacticity of 50-90%, average cell mass M _n from 800 to 75000 is used as the initial 1,2-polybutadiene a content in macromolecules of links yields of 1,2 and 1,4 polymerizations are 60-95 and 5-40 mol.%, respectively.

The inventive method allows to obtain polymer products of the formula (1) with a degree of functionalization (content of alkoxycarbonyl-substituted cyclopropane groups) of 28-36% and number average molecular weight M _n from 1000 to 88000.

When implementing the proposed method used industrial samples of 1,2-polybutadiene produced by JSC "Efremovskiy Zavod SK", as well as a polymer brand JSR RB-830 manufactured by "Japan Synthetic Rubber Co." (Japan). 1,2-polybutadiene was purified by reprecipitation in the chloroform-ethanol system, then the polymer was washed twice with alcohol and dried under vacuum at 60 ° C to constant weight.

Copper (II) triflate - Cu (OTf) ₂ [chemical name - copper (II) trifluoromethanesulfonate; was used as a catalyst; (CF ₃ SO ₃ ) ₂ Cu] from Acros (CAS No. 34946-82-2).

As the alkyl diazo diacetate, diazoacetates with various alkyl radicals can be used, in particular methyl diazo acetate, which was prepared according to a known method, was used (L. Titze, Eicher T. Preparative Organic Chemistry. M: Mir, 1999, p.274).

The invention is illustrated by the following examples.

Example 1

To 0.134 g (0.37 mmol) of Cu (OTf) _{2 was} added 10 ml of methylene chloride and stirred until complete dissolution. To the resulting solution was added 2.00 g (37 mmol) of 1,2-polybutadiene in 40 ml of methylene chloride. Used 1,2-polybutadiene syndiotactic structure with a number average molecular weight of M _n = 52600, the content of 1,2- and 1,4-polymerization units of 85 and 15 mol.%, Respectively, the degree of syndiotacticity 53%.

To the resulting mass, with stirring at 40 ° C, 3.70 g (37 mmol) of methyldiazoacetate in 10 ml of CH ₂ Cl _{2 were} slowly dosed. The molar ratio of 1,2-PB: MDA: catalyst — Cu (OTf) ₂ was 1: 1: 0.01. The reaction was carried out until the gas evolution ceased. After the synthesis was completed, the polymer was precipitated from the reaction mass with ethanol, purified by reprecipitation in the chloroform-ethanol system, and dried in vacuum.

The resulting polymer has a degree of functionalization (content of alkoxycarbonyl-substituted cyclopropane units) 30% and the number average molecular weight M _n = 64300.

Examples 2-7. All operations were carried out in accordance with example 1. The experimental results are shown in table 1.

The content of alkoxycarbonyl-substituted cyclopropane groups in the polymer was determined by ¹³ C NMR spectroscopy by signal intensity. Quantitative ¹³ C NMR experiments were performed in the regime with broadband decoupling from protons and a delay between pulses of 12 seconds.

The assignment of signals (ppm) in the ¹³ C NMR spectrum of the modified polymer is given below:

The ¹ H NMR and ¹³ C NMR spectra were recorded on a Bruker AM-300 spectrometer with an operating frequency of 75.46 MHz, CDCl ₃ solvent, internal TMS standard.

¹ H NMR Spectrum (CDCl ₃ , TMS, δ, ppm): 2.21-2.38 (m, C2H); 5.17-5.60 (m, C13H); 4.75-4.84 (m, Cl4H ₂ ); 0.75-0.91 (m, C ₁₆ N _cis ); 1.25-1.48 (m, C16H _trans ); 5.20-5.60 (m, C6, C7H _{cis + trans} ); 1.25-1.48 (m, C10, C11H); 1.47-1.72 (m, C9, C12H ₂ ); 1.81-2.14 (m, C5, C8H ₂ ); 1.43-1.65 (m, C15, C16H); 1.80-2.20 (m, C1H ₂ ); 3.61 (s, OCH ₃ ), OEt (3.26 k, 1.14 t).

¹³ C NMR spectrum (CDCl ₃ , TMS, δ, ppm): 35.6-36.44 (t, C9, C12); 38.55-38.93 (d, C2); 25.31-27.95 (d, C4); 40.17-42.16 (t, C1, C3, C5, C8); 33.34-34.21 (d, C10, C11); 114.41 (t, C14); 142.89 (d, C13); 18.57 (d, C15); 14.11 (t, C16); 28.30 (d, C17); 173.16 (s, C18); 28.50 (d, C20); 127.58, 130.55 (d, C6, C7, cis + trans); 51.43 (q, OCH ₃ ); OEt (64.32 t, 14.57k); 174.95 (s, C21).

From the data of table 1 it follows that the method of obtaining polymer products of the formula (1) proposed in the invention allows to synthesize modified polymers

- characterized in comparison with the prototype significantly (2.2-2.8 times) a higher degree of functionalization;

- having different number average molecular weight (M _n ) from 1000 to 88000 amu

In addition, modified polymers with different spatial structures (configurations) of macromolecules can be obtained by this method: with an atactic or syndiotactic arrangement of alkoxycarbonyl substituted cyclopropane groups.

Thus, the proposed method enables the targeted production of polymer products with a given degree of functionalization, molecular weight, spatial arrangement of cyclopropane groups, depending on the requirements for the polymer. Using the proposed method allows to obtain polymer products (1) containing alkoxycarbonyl substituted cyclopropane groups with a wider set of properties compared to the prototype, which expands the possibilities of their practical use.

Claims (3)

1. The method of producing polymers with substituted cyclopropane groups in the main chain or side links

consisting in the interaction of 1,2-polybutadiene with alkyl diazoacetate in an organic solvent in the presence of a catalyst, characterized in that copper (II) triflate - Cu (OTf) _{2 is} used as a catalyst in a molar ratio of 1,2-polybutadiene: alkyl diazoacetate: catalyst 1 : 0.5-1: 0.01. 2. The method according to claim 1, characterized in that the initial 1,2-polybutadiene is 1,2-polybutadiene of an atactic structure with a number average molecular weight M _n from 800 to 70,000, the content of units 1,2- and 1 in the macromolecules, 4-polymerization of 60-75 and 25-40 mol.%, Respectively. 3. The method according to claim 1, characterized in that 1,2-polybutadiene of a syndiotactic structure with a degree of syndiotacticity of from 50 to 90%, a number average molecular weight M _n of 35,000 to 75,000, and content in macromolecules is used as the starting 1,2-polybutadiene units of 1,2- and 1,4-polymerization of 75-95 and 5-25 mol.%, respectively.