RU2062272C1 - Method for production of (co)polymers of 1,1,2-trifluorobutadiene-1,3 - Google Patents

Abstract

FIELD: production of polymers. SUBSTANCE: copolymers of 1,1,2-trifluorobutadiene with other monomers are prepared by aqueous-emulsion polymerization at 1-20 C and pH 3.5-7 in the presence of emulsifier and initiator. Complexes of alkyl cobalt (III) with tridentant ligands are used as said initiator, its quantity being 0.04-0.3 mass parts per 100 mass parts of monomers. Alkyl1{2- [(2-aminoethyl)imino]-3-alkyl2-pent-3-en-4-olate}(1,2-ethane diamine)- cobalt (III) halides where alkyl 1 represents C₁-C₁₆alkyl, alkyl 2 represents H₁C₂H₅, H-C₇H₁₅, halide is iodine or bromine are used as aforementioned ligands. EFFECT: improves efficiency of the method.

Description

 The invention relates to the field of producing fluorinated polymers. Fluorinated polymers are widely used in various fields of technology due to their thermal and chemical resistance, as well as resistance to climatic factors and high physical strength.

A known method of producing copolymers of 1,1,3-trifluorobutadiene (TFB) with other fluorinated dienes by the method of emulsion, suspension and block polymerization in the presence of a peroxide initiator. However, the process is carried out at a temperature of 25-60 ^o C and elevated pressure for from 14 to 41 hours [1]
The closest in technical essence and the achieved result to the claimed technical solution is a method for producing copolymers of 1,1,2-trifluorobutadiene-1,3 by the method of emulsion polymerization in the presence of an emulsifier and initiator, which is a redox system [2] The disadvantages of the method include the process at elevated temperature (25-50 ^o C) and pressure.

 An object of the invention is to reduce the temperature of the process, reducing its duration and carrying out the process at atmospheric pressure.

где R алкил, содержащий C₁-C₁₆, R' H, C₂H₅, н-С₇Н₁₅, X 1, Br в количестве 0,04-0,3 мас. ч. на 100 мас.ч. мономеров, и процесс полимеризации проводят при температуре 1-20^oC и рН 3,5-7.This result is achieved by the fact that in the method for producing (co) polymers 1,1,2-trifluorobutadiene-1,3 by water-emulsion polymerization of 1,1,2-trifluorobutadiene and a second comonomer in the presence of an emulsifier and an initiator, alkyl cobalt complexes are used as an initiator (III) with tridentate ligands of the general formula:

where R is alkyl containing C ₁ -C ₁₆ , R 'H, C ₂ H ₅ , nC ₇ H ₁₅ , X 1, Br in an amount of 0.04-0.3 wt. hours per 100 parts by weight monomers, and the polymerization process is carried out at a temperature of 1-20 ^o C and a pH of 3.5-7.

 Comparative analysis with the prototype allows us to conclude that when conducting emulsion (co) polymerization of 1,1,2-trifluorobutadiene, a new type of initiator was used, alkyl cobalt complexes with tridentate ligands. Thus, the claimed technical solution meets the criterion of "novelty."

 An analysis of known technical solutions [1, 2] showed that the use of alkyl cobalt (III) complexes with tridentate ligands as initiators of water-emulsion polymerization can reduce the temperature and pressure of the process, as well as reduce the reaction time. Thus, the claimed technical solution meets the criterion of "inventive step".

 The indicated complexes are alkyl {2 - [(2-aminoethyl) imino] -3-alkylpent-3-en-4-olate} (1,2-ethanediamine) cobalt (III) halides (symbolic formula [RCo (3-R ' -acacen) (en)] X); special case (R '= H) - alkyl- {2 - [(2-aminoethyl) imino] pent-3-en-4-olate} (1,2-ethanediamine) cobalt (III) halides ([RCo (acacen) (en)] X was first synthesized by the authors using the following procedure.

The synthesis is carried out in an argon atmosphere at a temperature of 15-25 ^o With constant stirring. 430 ml of methanol, 12, 3 ml (120 mmol) of acetylacetone, 10.3 ml of a 70% aqueous solution of ethylenediamine (120 mmol), 14.1 g (60 mmol) of 6-aqueous cobalt dichloride, 19, are sequentially introduced into the reactor. 3 ml of a 50% aqueous solution of NaOH, 1 ml of a ₂ % solution of PdCl ₂ in a 1M aqueous KCl solution, 21 ml (273 mmol) of ethyl bromide. A solution of 3.2 g of NaBH ₄ (85 mmol) in 25 ml of a 5% aqueous NaOH solution was added dropwise evenly over 5 hours. After gas evolution, the reaction mixture was stirred for 1 hour. Then it is filtered, the solution is evaporated to a volume of 100 ml at a residual pressure of 10-20 mm Hg. and a bath temperature of not higher than 40 ^° C. Then, 20 g of NaBr are added and, with cooling, 100 ml of water, and the mixture is evaporated in the same way to a volume of 100 ml. Crystallization is carried out at 0 ^o C, the precipitate is filtered off, washed with 15 ml of ice water and dried in air. Then it is washed with dichloromethane, in portions (only 150-200 ml), until the green color of the wash liquid disappears. Dry the product again in air. The target product is a red crystalline powder. If necessary, recrystallization from methanol with the addition of sodium bromide is carried out. For identification, ion-exchange TLC on SiO _{2 is used} (silofol plates, eluent 0.1 N sodium acetate in methanol-water 4: 1 by volume). The cleanliness criterion is the presence of a single spot on the plate, as well as the almost complete discoloration of the complex solution when hydrochloric acid is added. The output and value of the separation factor R _f are shown in table 1.

 In the synthesis of the complexes listed in table 1, the following halide alkyls are used: methyl iodide, ethyl bromide, n-butyl bromide, isopropyl bromide, n-amyl bromide, n-octyl bromide, n-cetyl bromide, cyclohexyl bromide, sec. octyl bromide, as well as acetylacetone or its 3-ethyl and 3-n-heptyl derivatives.

The structure of the complexes is proved on the basis of ¹ H-NMR, IR spectra and analysis of acidolysis products. ¹ H-NMR spectra (solvent D ₂ O or DM ₃ OD, 200 MHz, internal standard sodium 2,2-dimethyl -2-silapentene-5-sulfonate) of the synthesized alkyl cobalt complexes are similar to each other. The data for complex 2 (Table 1) in D ₂ O are given below (identified signal, δ, ppm multiplicity): CH ₃ CH ₂ Co, 0.60, t; CH ₃ -C = N, 1.70, S; CH ₃ —CO, 1.94, S; CH, 4.98, S. The IR spectra of complexes 1–11 have characteristic absorption bands in the region of 3100–3260 cm ^–1 (wide) and 3280–3350 cm ^–1 (narrow), which are related to NH stretching vibrations.

 Analysis of the acidolysis products of the synthesized complexes 1-11, carried out by gas-liquid and thin-layer chromatography, confirms the above structural formula. The structure of the complexes is also confirmed by the data of elemental analysis (Table 2).

 Complexes 1-11 in the solid state are stable in the dark and safe during storage.

Example 1 (according to the invention). In a reactor with a stirrer, 100 parts by weight are mixed. TFB with an aqueous phase comprising 4 parts by weight Na alkyl sulphonate (E-ZO) with an alkyl substituent length of C ₁₅ , 0.1 parts by weight the initiator of complex N 1 (table. 1) and 200 wt. including water. The process is carried out with stirring in a nitrogen atmosphere at a temperature of +1 ^o C for 45 hours. Atmospheric pressure, pH 5, monomer conversion 58%
Example 2. In a reactor with a stirrer mix 75 wt.h. TFB and 25 parts by weight isoprene with an aqueous phase, including 3 parts by weight E-ZO, 0.04 parts by weight initiator - complex N 2 (table. 1), 0.1 wt.h. Na ₂ NRA ₄ , 1.7 parts by weight KH ₂ PO ₄ to maintain pH and 200 wt.h. water. The process is carried out with stirring in a nitrogen atmosphere at atmospheric pressure and a temperature of 3 ^o C for 5.5 hours. pH 5.5, monomer conversion 76%
Examples 3-6. Perform analogously to example 2, with a change in the type of comonomer, temperature, pH, type of emulsifiers, concentration of ingredients, the presence of buffer compounds, the use of alkyl cobalt (III) complexes with tridentate ligands of various structures. Since all copolymerization processes are carried out in a sealed reactor, then with increasing temperature up to 20 ^o With the excess pressure in the apparatus does not exceed 3 MPa.

Example 7 (prototype). In an autoclave, 50 parts by weight are mixed with a stirrer. TFB and 50 wt. including perfluorobutadiene-1.3 with an aqueous phase, including 1 wt.h. initiator K ₂ S ₂ O ₈ , 2 parts by weight emulsifier - Cl (CF ₂ CFCI) ₃ CF ₂ COOK and 200 wt.h. water. The process is carried out with stirring at a temperature of 50 ^o C and a pressure of 35 kg / cm ² for 24 hours. pH 7, monomer conversion 40%
The polymerization recipes and process parameters, as well as some properties of (co) polymers are shown in table 3.

 In copolymerization recipes, monomers of various nature diene hydrocarbons, acrylic esters, chloroprene, acrylonitrile, as well as fluorine-containing dienes and vinyl monomers can be used. As emulsifiers can be used anionic (E-30), cationic (cetylpyridinium chloride) and fluorinated surfactants, for example salts of perfluoroenanthate and prefluoropelargon acid. To obtain uncrosslinked copolymers should be used up to 0, 3 wt.h. molecular weight regulators such as mercaptans.

The decrease in process temperature below 1 ^o With impractical, because leads to freezing of the aqueous phase. An increase in temperature above 20 ^o With will require an increase in pressure in the reactor.

 Using an initiator concentration of less than 0.04 parts by weight slows down the polymerization. An increase in initiator concentration of more than 0.3 parts by weight does not increase the speed of the process.

 Homolytic decomposition of alkyl cobalt complexes occurs under the influence of a proton. Therefore, in alkaline media (pH> 7), the complexes are stable and almost no polymerization occurs. At pH <3.5, a violation of the stability of the emulsion system is observed, and coalescence of particles occurs, leading to coagulation. Thus, it is optimal to carry out the polymerization at pH 3.5-7.

 Given in the table. 3 data indicate that the use of synthesized complexes of alkyl cobalt (III) with tridentate ligands allows the process of emulsion (co) polymerization of trifluorobutadiene with other monomers at low temperatures with high speeds.

Literature
1. The patent of Germany N 1089973, cl. C 07 C, publ. 6.04.61.

 2. US patent N 3398128, CL. C 07 C, publ. 08.20.68. TTT1 TTT2 TTT3

Claims (1)

A method of producing (co) polymers of 1,1,2-trifluorobutadiene-1,3-water-emulsion polymerization of 1,1,2-trifluorobutadiene and a second comonomer in the presence of an emulsifier and an initiator, characterized in that alkyl cobalt complexes (III ) with tridentant ligands of the general formula:

where R is alkyl containing C ₁ -C ₁₆ ;
R 'H, C ₂ H ₅ , n-C ₇ H ₁₅ ;
XI, Br in an amount of 0.04-0.3 parts by weight per 100 parts by weight / co / monomers,
and the polymerization process is carried out at a temperature of 1-20 ^o C and a pH of 3.5-7.

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