RU2470032C1 - Method of producing polymers containing dichlorocyclopropane groups - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to high-molecular weight compounds, particularly obtaining polymer products containing dichlorocyclopropane macromolecules. Described is a method of producing polymers by reacting 1,2-polybutadiene with chloroform and aqueous solution of an alkali metal in the presence of a quaternary ammonium salt as a phase-transfer catalyst. The starting polymer used is syndiotactic 1,2-polybutadiene with syndiotacticity ranging from 50 to 90%, number-average molecular weight M_n from 30000 to 75000, content of 1,2- and 1,4-polymerisation links in the macromolecules of 80-95 mol % and 5-20 mol %, respectively.

EFFECT: obtaining polymer products with degree of functionalisation (content of dichlorocyclopropane groups) of up to 98%, content of (a+b) links from 80 to 95 mol % and molecular weight of more than 30000 amu.

1 tbl, 7 ex

Description

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

These polymer products are copolymers containing dichlorocyclopropane groups in the side chains (b) and in the main chain (d) of the macromolecules, as well as carbon-carbon double bonds in the side chains (a) and in the main chain (c). Polymer products (1) can find application in the composition of adhesive compositions, sealants, paints and varnishes, as modifiers and flame retardants in various compositions of thermoplastics and elastomers.

Known methods for producing polymer products (1) by chemical modification of polybutadiene containing 1,2- and 1,4-polymerization of 1,3-butadiene in the composition of the macromolecules. Polybutadiene, which is the feedstock for producing polymers (1), is synthesized in industry by polymerization of 1,3-butadiene on complex catalysts [RF Patent 2072362, cl. C08F 136/06, C08F 36/06, C08F 136/00, C08F 36/00; publ. 01/27/1997. RF patent 2177008, cl. C08F 136/06, C08F 36/06, C08F 36/04, C08F 4/70; publ. 12/20/2001. U.S. Patent 4,182,813, CL C08F 136/06, C08F 36/00, C08F 4/00; publ. 01/08/1980].

The method for producing polymers of formula (1) is based on the generation of dichlorocarbene by the action of an aqueous solution of sodium hydroxide on chloroform in the presence of an interphase transfer catalyst (equation 2) and its subsequent attachment in situ to the double bond of polybutadiene with the formation of a polymer product containing dichlorocyclopropane groups in the side units and in the main chain of macromolecules (equation 3):

The known method [RF patent 2073019, class. C08F 8/18; C08F 19/18; publ. 02/10/1997] the preparation of polymers containing dichlorocyclopropane groups, consisting in the interaction of cis-1,4-polybutadiene with chloroform and an aqueous solution of an alkali metal in the presence of a phase transfer catalyst, which is used as a quaternary ammonium salt or tertiary amine. The reaction is carried out in a hydrocarbon solvent (toluene, gasoline, cyclohexane or a mixture thereof) at a temperature of 20-40 ° C for 0.5-4 hours. The resulting polymer product is washed with water, and then isolated by water degassing. The degree of functionalization (content of dichlorocyclopropane groups) of the polymer is from 10 to 80 mol.%.

However, this method does not allow to obtain polymers of the formula (1) with a total content of side units (a + b) of more than 10 mol. % since 1,4-polybutadiene with a content of 1,2 units of less than 10 mol is used as the initial polybutadiene. %

Closest to the proposed invention is a method (A. Konietzny, U.Biethat "Zur Anlagerung von Dichlorcarben an niedermolekulare cis- und Vinyl-cis-Polybutadiene" // Die Angewandte Makromolekulare Chemie, 1978, Vol. 74, P.61-79, No. 1176) for the preparation of polymers containing dichlorocyclopropane groups, based on the interaction of 1,2-polybutadiene (1,2-PB) with chloroform and an aqueous alkali metal solution in the presence of an interphase transfer catalyst, using a quaternary ammonium salt or tertiary amine. In this method, to obtain modified polymer products using low molecular weight 1,2-polybutadiene atactic structure with a number average molecular weight M _n from 790 to 1800 amu and a content of 1,2 units of not more than 52%. The reaction is carried out at a temperature of 40-50 ° C for 2-6 hours. The degree of functionalization (content of dichlorocyclopropane units) of the polymer is from 20 to 92 mol.%.

However, this method has several serious limitations:

- in this way it is impossible to obtain polymers of the formula (1) with a total content of side units (a + b) of more than 52%, the properties of which differ significantly from the properties of the polymers described in the closest analogue;

- the method does not allow to obtain modified polymer products with a molecular mass of M _n more than 2000, and the resulting polymers are highly viscous liquids, which limits the possibility of their practical application;

- the modified 1,2-polybutadiene obtained by this method due to the low molecular weight is characterized by a small complex of physico-mechanical properties; Due to their low strength, modified polymers can find only limited use.

In addition, a close analogue does not make it possible to obtain polymers having not only atactic, but also stereoregular - syndiotactic structure of macromolecules, whose properties differ significantly from the properties of atactic polymers. All this significantly limits the capabilities of this method.

An object of the present invention is a method for producing polymer products of the formula (1) containing dichlorocyclopropane groups in the main chain and in the side chains of macromolecules and different from the polymers described in the prototype:

- the composition of the polymer product - the total content in the polymer of the lateral 1,2 units (a) and 1,2 units modified with dichlorocyclopropane groups (b) is at least 80 mol%;

- stereoregular - syndiotactic structure of macromolecules, i.e. the syndiotactic arrangement of substituents (dichlorocyclopropane groups or vinyl units) in the polymer chain;

- significantly higher molecular weight (M _n ≥30000), which can be purposefully changed in a wide range of values depending on the requirements for the polymer product;

- a wider range of physicomechanical properties (modified polydienes are solid thermoplastic polymer products).

The specified technical problem is achieved by the fact that in the interaction of 1,2-polybutadiene with chloroform and an aqueous solution of an alkali metal in the presence of a quaternary ammonium salt as a phase transfer catalyst at a temperature of 40-50 ° C for 2-6 hours as 1.2- polybutadiene use syndiotactic 1,2-polybutadiene with a degree of syndiotacticity of 50-90%, number average molecular weight M _n from 30,000 to 75,000, the content of 1,2- and 1,4-polymerization units in the macromolecules of 80-95 and 5-20 mol.% , respectively, and the synthesis is carried out at molar the ratio of 1,2-PB: CHCl ₃ : NaOH: catalyst equal to 1: 4-14: 1.5-2: 0.001-0.002.

The inventive method allows to obtain polymer products of the formula (1) syndiotactic structure with a degree of functionalization (the content of dichlorocyclopropane groups) from 20 to 98% and the number average molecular weight M _n from 45,000 to 90,000.

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

Quaternary ammonium salts such as triethylbenzylammonium chloride (TEBAH) were used as a phase transfer catalyst; dimethylbenzyl (C ₁₀ -C ₁₈ - alkyl) ammonium chloride (catamine AB).

The invention is illustrated by the following examples.

Example 1. In a glass reactor equipped with a stirrer, reflux condenser and dropping funnel, 3.0 g (55.6 mmol) of 1,2-polybutaddenene was charged, 26.6 g (222.4 mmol) of chloroform was added and stirred until dissolved . A syndiotactic 1,2-polybutadiene with a number average molecular weight of M _n = 30,000, a content of 1,2 and 1,4 polymerization units of 80 and 20 mol%, respectively, and a degree of syndiotacticity of 50% was used. To the resulting solution was added 0.024 g (0.11 mmol) of the TEBAH catalyst, heated to 50 ° C, and 8.9 g (111.2 mmol) of a 50% aqueous sodium hydroxide solution were dosed with vigorous stirring. The molar ratio of 1,2-PB: CHCl ₃ : NaOH: catalyst was 1: 4: 2: 0.002. The synthesis was carried out with vigorous stirring of the reaction mass at 50 ° C for 4 hours. Then the organic layer was separated and washed twice with water. The polymer from the organic phase was precipitated with alcohol and dried in vacuum at 60 ° C. The resulting polymer contains 50.8 wt.% Chlorine, which corresponds to the degree of functionalization of the polymer 98%, has a number average molecular weight M _n = 45000, the content of units (a + b) is 80%, and units (c + d) are 20%.

The chlorine content in the polymer was determined by burning according to Sheniger (Klimova V.A. Basic micromethods for the analysis of organic compounds. M: Chemistry. 1975. - 208 p.).

The degree of functionalization of the polymer was calculated by the formula:

where: w (Cl) is the actual chlorine content in the polymer, wt.%;

w _p (Cl) is the calculated amount of chlorine in the polymer at 100% functionalization of carbon-carbon double bonds, wt.% (for dichlorocyclopropane derivatives of 1,2-PB w _p (Cl) is 51.8 wt.%).

The content of units (a) and (c) in the starting 1,2-polybutadiene and units (b) and (d) in the modified polymer was determined by ¹³ C NMR spectroscopy. Quantitative ¹³ C NMR experiments were performed in the mode with broadband proton decoupling and delay between pulses 12 seconds. 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. The assignment of signals (ppm) in the ¹³ C NMR spectrum of the modified polymer is given below:

¹³ C NMR spectrum (δ, ppm): 35.58 (t, C1); 40.26 (d, C2); 35.06 (t, C3); 45.70 (d, C4); 27.43-32.54 (t, C5, C8, cis + gras); 127.92-133.23 (d, C6, C7, cis + trans); 31.53 (t, C9, C12); 32.93 (d, C10, C11); 148.83 (d, C13); 115.36 (t, C14); 48.83 (d, C15); 27.56 (t, C16); 60.83 (s, C17); 65.90 (s, C18).

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

From the obtained results it follows that the use of syndiotactic 1,2-polybutadiene with a number average molecular weight below 30,000 as the starting polymer does not allow to obtain modified 1,2-PB in the solid state of aggregation (Example 6). The use of an initial product with a molecular weight of more than 75,000 leads to a sharp decrease in the degree of functionalization of the resulting modified polymer due to an increase in the viscosity of the polymer solution (Example 5). The synthesis at a molar ratio of 1,2-PB: CHCl ₃ less than 1: 4 does not provide the necessary degree of functionalization of the obtained modified polymer (example 7). This circumstance is due to the fact that, at the indicated molar ratio, the amount of chloroform is insufficient to dissolve the starting polymer. An increase in the molar ratio of 1,2-PB: CHCl ₃ more than 1:14 leads to an excessive consumption of chloroform. The optimal is the molar ratio of 1,2-PB: NaOH equal to 1: 1.5-2. Reducing the consumption of sodium hydroxide less than a ratio of 1: 1.5 leads to a decrease in the degree of functionalization of the resulting modified polymer. Moreover, the amount of sodium hydroxide is insufficient to generate the required amount of dichlorocarbene (according to equation 2). The molar ratio of 1.2-PB: catalyst equal to 1: 0.001-0.002 ensures the process at a sufficient speed. Thus, the synthesis is carried out at a molar ratio of 1,2-polybutadiene: CHCl ₃ : NaOH: a catalyst equal to 1: 4-14: 1.5-2: 0.001-0.002 ensures the optimal course of the process of obtaining polymer products containing dichlorocyclopropane in the macromolecules groups.

As the starting 1,2-polybutadiene, 1,2-polybutadiene with a content of 1,2 units of less than 80 mol% cannot be used, because they are characterized by a low degree of syndiotacticity (less than 50%) and are atactic polymers, the properties of which differ significantly from the properties of stereoregular syndiotactic 1,2-polybutadiene. 1,2-Polybutadiene with a content of 1,2-units of more than 95 mol.% And a degree of syndiotacticity of more than 90% is not produced by industry, their preparation requires the use of special methods and is expensive. In addition, due to the high degree of crystallinity of these polymers, their processing is difficult.

Thus, the proposed method for producing polymer products of the formula (1) allows to synthesize modified polymers having, in comparison with the prototype:

- stereoregular - syndiotactic arrangement of substituents (dichlorocyclopropane groups or vinyl units) in the polymer chain;

- a different composition - the content of units (a + b) is 80-95 mol.%;

- significantly higher molecular weight M _n from 45,000 to 90,000 amu;

- representing solid polymer products.

The proposed method makes it possible to purposefully obtain polymer products (1) with a syndiotactic arrangement of substituents in a polymer chain with a given degree of functionalization and molecular weight, depending on the requirements for the polymer. Using the proposed method allows to obtain thermoplastic polymer products (1) with a higher, in comparison with the prototype, complex physical and mechanical properties, which expands the possibilities of their practical use.

Table 1 The results of experiments on the synthesis of polymer products (1) No. p / p The name of indicators Prototype Example No. one 2 3 four 5 6 7 one Characterization of the starting 1,2-polybutadiene: - M _n 790 30000 45000 60,000 75,000 85000 20000 45000 - content, mol.%, 1,2 links 52 80 85 95 84 85 80 85 1,4-links 48 twenty fifteen 5 16 fifteen twenty fifteen - degree of syndiotacticity,% 0 fifty 75 90 60 70 55 75 2 Reaction conditions: - temperature, ° C 40 fifty fifty 40 fifty fifty 40 fifty - duration, hour 5 6 2 5 four four 3 four - molar ratio 1,2-PB: chloroform: NaOH: cat. 1: 2: 2: 0.001 1: 4: 2: 0.002 1: 8: 1,5: 0,001 1: 12: 2: 0.001 1: 14: 2: 0.002 1: 8: 2: 0.002 1: 4: 2: 0.002 1: 3: 2: 0.002 - catalyst TEBAH TEBAH Catamine AB TEBAH TEBAH TEBAH TEBAH TEBAH 3. The characteristic of the modified 1,2-PB: - M _n - 45000 50,000 72000 90,000 88000 20000 47000 - chlorine content, wt.%, 41.5 50.8 10,4 23.3 36.3 5.2 20.7 2.6 - degree of functionalization,%, 80 98 twenty 45 70 10 40 5,0 - content links (a + b), mol.%, 52 80 85 95 84 85 80 85 - state of aggregation viscous liquid solid matter solid matter solid matter solid matter solid matter viscous liquid solid matter

Claims (1)

A method of producing polymers containing dichlorocyclopropane groups in the main chain and side chains of macromolecules by reacting 1,2-polybutadiene with chloroform and an alkaline metal aqueous solution in the presence of a quaternary ammonium salt as a phase transfer catalyst at a temperature of 40-50 ° C for 2-6 h, characterized in that as the starting polymer using syndiotactic 1,2-polybutadiene with a degree of syndiotacticity from 50 to 90% and with a number average molecular weight M _n from 30,000 to 75,000, the content in ma the cromolecules of the 1,2- and 1,4-polymerization units are 80-95 and 5-20 mol.%, respectively, and the interaction of the reagents is carried out at a molar ratio of 1,2-polybutadiene: chloroform: sodium hydroxide: catalyst equal to 1: 4-14 : 1.5-2: 0.001-0.002.