RU2340588C2 - Method of obtaining hexafluorobutadiene - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method lies in direct interaction of chlorotrifluorethylene with zinc in presence of metal-complex catalyst based on solutions of organic complexes of transition metals in polar organic solvents and possibly in presence of activating additive, as such metal halogenides are used.

EFFECT: simplification of hexafluorobutadiene obtaining process.

6 cl, 3 tbl, 21 ex

Description

The invention relates to the field of chemical technology for producing perfluoroolefins, namely hexafluorobutadiene CF ₂ = CF-CF = CF ₂ (hereinafter GFBD), which finds application in the synthesis of various (co) polymers and in microelectronics in the manufacture of integrated circuits.

State of the art

A known method for producing HFBD based on 1,2-dibromochloro-trifluoroethane by attaching it during telomerization to chlorotrifluoroethylene under the influence of UV radiation to produce 1,4-dibromo-2,3-dichlorohexafluorobutane and dehalogenation of the latter with activated zinc powder in boiling ethanol [Dedek V ., Chvatal Z., J. Fluor. Chem., 1986, v. 32, No. 4, pp. 363-379]. The disadvantages of this method are the difficulties of using low-tech ultraviolet radiation, the low yield of butane telomere (38%) and the difficulty of obtaining pure HFBD caused by contamination of HFBD by-products, which are formed from aliphatic alcohol during its chlorination under dehalogenation in boiling alcohol in the presence of traces of water.

The method for producing HFBD has long been known [R.N. Haszeldyne, J.E. Osborne, J. Chem. Soc, 1955, No. 11, pp. 3880-3888], including the doubling of 1,2-dichlorotrifluoroiodoethane to obtain 1,2,3,4-tetrachlorohexafluorobutane (TCHPB) and dehalogenation of the latter in powder boiling zinc ethanol. According to this method, HFBD is obtained by the action of zinc powder on TCHFB in boiling ethanol during reflux for 6 hours to obtain HFBD in 87% yield. In this case, the liquid components under normal conditions condense in a reflux condenser cooled by cold water and return to the reactor, gaseous components pass through a reflux condenser and condense in a trap cooled by dry ice.

The disadvantage of this method of obtaining pure GFBD is that carrying out the process at the boiling point of the solvent leads to contamination of the obtained GFBD with various organic impurities. These impurities according to gas chromatography in combination with mass spectroscopy are:

1. Partial dehalogenation products of ghcfb gross formula C ₄ F ₆ Cl ₂ .

2. Products of partial reduction of HFBD with zinc of the general formula C ₄ H _x F _6-x , where x = 1-3.

3. Chlorinated hydrocarbons - products of chlorination of aliphatic alcohol in an acidic environment in the presence of zinc chloride and traces of water.

All of these impurities, including chlorinated hydrocarbons, to one degree or another pass through the reverse condensation system and accumulate in the low-temperature receiver together with the HFBD. This leads to contamination of GFBD with the listed impurities.

In particular, it was found that methyl chloride, methylene chloride, isopropyl chloride and, possibly, ethyl chloride in at least low concentrations are likely to form azeotropic mixtures with HFBD. Therefore, the contamination of GFBD with these impurities is a particularly acute problem.

A known method for producing HFBD by dehalogenation of 1,4-dibromo- or 1,4-diiodoperfluorobutanes with ethyl magnesium bromide in tetrahydrofuran in 96% yield (Gianangelo Bargigia, Vito Tortelli, Claudio Tonelli, Silvana Modena; US Patent 5082981).

The disadvantages of this method include the use as starting compounds of inaccessible dibromo- or diiodoperfluorobutanes.

There is another method for producing HFBD by dehalogenation of 1,2,3,4-tetrachlorohexafluorobutane with zinc in absolute ethanol in 93.5% yield (R.P. Ruh, R.A. Davis, K.A. Allswde GB 798407).

The disadvantages of this known method include the necessity of using absolute ethanol or other anhydrous alcohols as solvents and their subsequent regeneration.

From RU 2247104, February 27, 2005, a method is known for producing HFBD from polyhalogenbutanes by dehalogenation with dispersed zinc in a polar organic solvent, in which the second reaction component, polyhalogenbutane, is dosed into a liquid reaction mixture containing a solvent and dispersed zinc, gradually, with a feed rate which ensures that the process temperature is 8-50 ° C below the boiling point of the solvent.

It is proposed to carry out the method in three stages.

In this case, in the first stage, the reaction mixture containing the solvent and dispersed zinc is heated to a temperature of 20-50 ° C below the boiling point of the solvent and a one-time 5-18 mol.% Polyhalogenbutane is introduced from the stoichiometric ratio; then the reaction mixture is stirred until a temperature jump of 8-19 ° C appears, and then polyhalogenbutane is supplied in a total amount of 60-95 mol% of the stoichiometric ratio with the feed rate, which ensures that the temperature is maintained at least 8-40 ° C lower boiling point of the solvent.

Aliphatic alcohols with the number of carbon atoms 1-4, their esters with acetic acid or mixtures of aliphatic alcohols and ethers are used as a polar organic solvent. In the known method using as initial polyhalogenbutane formula:

CF ₂ X ¹ —CFX ² —CFX ² —CF ₂ X ¹ , where X ¹ , X ² = I, Br, Cl.

From RU 2272017, 03.20.2006, another method for producing GFBD is known.

The method is carried out due to the reaction of 1,2,3,4-tetrachlorohexafluorobutane with zinc in an aqueous medium at a temperature of 30-90 ° C. The reaction is carried out by dosing 1,2,3,4-tetrachlorohexafluorobutane in a reaction vessel containing zinc and water with the simultaneous selection of the resulting target product. Preferably, the process is carried out in the presence of a promoter, which uses acids, in particular sulfuric or hydrochloric acids, soluble salts of weak bases, such as zinc or ammonium halides, phase transfer catalysts such as quaternary ammonium salts, quaternary phosphonium salts, tetrakis halides (dialkylamino ) phosphonium or halides N, N ', N' '- hexaalkyl substituted guanidinium or a mixture of these substances. The method is also not without difficulties because of the reaction in an aqueous medium and because of the need for strict control of the dosage rate of the starting tetrachlorohexafluorobutane and simultaneous rapid separation of the resulting target product from condensing impurities.

Known multi-stage methods for producing GFBD, giving low yields of the target product. So, the method disclosed in Japanese patent 2001114710, publ. 1999, includes several stages:

- obtaining CFBr ₂ CF _{3 by} isomerization of CF ₂ BrCF ₂ Br in the presence of a catalyst;

- obtaining CF ₂ = CF-Zn by reacting CFBr ₁ CF ₃ with zinc in an aprotic solvent;

- obtaining C ₄ F ₆ by reaction of CF ₂ = CF-Zn with a group of compounds containing ferric iron and divalent copper in an aprotic solvent.

US Pat. No. 2,777,004, publ. 01/08/1957, a multi-stage method for producing HFBD from symmetric dichlorodifluoroethylene is described, which includes the following steps:

1. Dimerization, which is carried out at a temperature of 275 ° C, a pressure of 2.8 Pa for 5-8 hours. At this stage, the following are achieved: selectivity - 87.3%, conversion - 86.8% and yield 75.8%

CFCl = CFCl → CFCl = CF-CFCl-CFCl ₂

2. Photochemical chlorination, which is carried out, obtaining a conversion of 96.1% and a selectivity of 99.4%

CFCl = CF-CFCl-CFCl ₂ + Cl ₂ → CFCl ₂ -CFCl-CFCl-CFCl ₂

3. Fluorination at a temperature of 250 ° C, resulting in a yield of up to 89.6%

CFCl ₂ -CFCl-CFCl-CFCl ₂ + SbF ₃ Cl ₂ → CF ₂ Cl-CFCl-CFCl-CF ₂ Cl

4. Dehalogenation of CF ₂ Cl-CFCl-CFCl-CF ₂ Cl with zinc in a polar solvent, which leads to the formation of HFBD with a selectivity of 93.7%, a conversion of 90.2%.

Each of these stages of synthesis is accompanied by rectification with the release of the corresponding product, which means doubling the number of stages.

Disclosed [US Patent 2894042, publ. 07/07/1959] an improved method for producing HFBD from symmetric dichlorodifluoroethylene. This method is carried out by dimerizing immediately dichlorodifluoroethylene in the presence of elemental fluorine. The method of obtaining 1,2,3,4-tetrachlorohexafluorobutane (CF ₂ Cl-CFCl-CFCl-CF ₂ Cl) is that the process is carried out at a temperature of minus 70-75 ° C with a yield of the target product of 30-40%. The main impurities are pentachloropentafluorobutane C ₄ F ₅ Cl ₅ and hexachloro-1,2,3,4-tetrafluorobutane C ₄ F ₄ Cl ₆ . The resulting 1,2,3,4-tetrachlorohexafluorobutane is dehalogenated with zinc dust in a polar solvent to obtain HFBD in 90.5% yield and 95% selectivity.

The disadvantage of the above methods of obtaining GFBD is their multi-stage.

Closest to the claimed is a method for producing HFBD by dechlorination of 1,2-dichlorohexafluorobutene-3, which is formed during the pyrolysis of C ₂ F ₃ Cl at 500 ° C, but with a very low yield. The dechlorination step is carried out in the presence of zinc in a solvent [Synthesis of organofluorine compounds, ed. Knunyants I.L., M., Chemistry, 1973, p.17].

From RU 2264376, November 20, 2005, a method for producing HFBD is known, which is carried out by pyrolysis of chlorotrifluoroethylene followed by dechlorination of 1,2-dichlorohexafluorobutene-3 in the presence of zinc in a solvent, and this method is characterized in that the initial chlorotrifluoroethylene is pyrolyzed at a temperature of from 505 to 600 ° C. for 0.5-15 s, then the resulting pyrolyzate is condensed at a temperature of from 0 ° C to minus 10 ° C, after which the condensate is rectified with the isolation of a fraction boiling at 59.0-59.5 ° C and containing 1.2- dichlorohexafluorocyclobutane C ₄ F ₆ Cl ₂ , then the fraction boiling at 63.5 -64 ° C and containing 1,2-dichlorohexafluorobutene-3, is subjected to dechlorination in a polar solvent at a temperature of 37-50 ° C.

Products not condensed in the condensation step are returned to pyrolysis.

The method allows for the pyrolysis stage with a conversion of 50-70%. Rectification of the pyrolyzate makes it possible to obtain marketable 1,2-dichlorohexafluorocyclobutane, as well as 1,2-dichlorohexafluorobutene-3, which is subjected to dechlorination to obtain crude HFBD.

As a result of rectification of raw GFBD, commodity GFBD is isolated.

The known method consists of the following stages:

1. Pyrolysis at a temperature of from 505 to 600 ° C with the formation of C ₄ F ₆ Cl ₂ cyclo and C ₄ F ₆ Cl ₂ linear:

CF ₂ = CFCl → C ₄ F ₆ Cl ₂ -cyclo + CF ₂ = CF-CFCl-CF ₂ Cl + impurities.

2. Rectification of pyrolysis products with the release of C ₄ F ₆ Cl ₂ cyclo (99.9%) and C ₄ F ₆ Cl ₂ linear (99.9%).

3. Dehalogenation of a C ₄ F ₆ Cl ₂ linear in the presence of a polar solvent:

CF ₂ = CF-CFCl-CF ₂ Cl + Zn → CF ₂ = CF-CF = CF ₂ + ZnCl ₂ .

As follows from the description of this known method for the production of HFBD, it is also quite technologically complicated: it is multi-stage and requires the use of high temperatures.

SUMMARY OF THE INVENTION

The technical task of the claimed invention is to simplify the technology for GFBD.

The stated technical problem is carried out by the method of producing HFBD by direct reaction of chlorotrifluoroethylene with zinc in the presence of a catalyst based on solutions of organic transition metal complexes in organic solvents and, if necessary, in the presence of an activating additive.

This method uses a metal complex catalyst obtained by mixing (preferably in situ) organic transition metal complexes with a complexing ligand in an organic solvent; in particular, nickel and palladium compounds are used as organic transition metal complexes. As a possible activating additive, a metal halide, in particular metal iodide or a mixture thereof, is used.

The reaction is carried out at 20-100 ° C, preferably at 50-80 ° C.

In particular, the reaction is carried out with an incomplete conversion of chlorotrifluoroethylene, which after separation of the reaction products by distillation can be returned to the process.

Information confirming the possibility of carrying out the invention

So, the technical result contributing to the solution of the above problem is to conduct a direct reaction of chlorotrifluoroethylene with zinc in the presence of a metal complex catalyst and possibly activating additives, which eliminates the need for multistage syntheses and allows the use of industrially available substances as the main raw material.

The method according to the invention uses metal complex catalysts based on organic transition metal complexes, in particular nickel and palladium, and nitrogen-containing heterocycles, aromatic benzonitrile, triarylphosphines are most often used as ligands (complexing agents). The nature of the ligand is not of fundamental importance and is selected from the point of view of low cost, availability and solubility of the resulting complexes in an organic solvent. The amount of ligand is chosen so as to ensure the conversion of the transition metal into a soluble complex and ranges from 2 to 5 equivalents per g-atom of metal. The use of more ligand is acceptable, but not rational in terms of the cost of the process. The complex can be prepared in advance, used in finished form, or prepared directly in the reaction mass with the introduction of an additional amount of ligand.

As a solvent for the preparation of the metal complex catalyst, polar organic solvents are used, in particular N-methylpyrrolidone (N-MPD), dimethylacetamide (DMAA), dimethylformamide (DMF). The amount of solvent is selected so as to ensure complete dissolution of the catalyst at the reaction temperature. The use of more solvent is irrational in terms of subsequent regeneration of the transition metal.

The temperature of the dechlorination reaction determines the speed of the process: an elevated temperature contributes to the rapid course of the reaction, but also reduces the selectivity of the process. Low temperature allows to achieve high selectivity, however, significantly lengthens the reaction time and reduces the productivity of the process.

Typically, a temperature of 20-100 ° C, more often 50-80 ° C, is used; this mode can be considered optimal from the point of view of maintaining a fast and controlled reaction.

The amount of zinc introduced into the dechlorination process can vary between 2-100 g-atoms per 1 mol of the initial chlorotrifluoroethylene. A larger amount contributes to the rapid progress of the reaction, but usually 5-20 g-metal atoms are sufficient. Unreacted zinc can be easily separated by filtration and reintroduced into synthesis. The form in which the metal is used in the synthesis is not essential, however, the use of granular zinc or its shavings makes it difficult to mix and subsequently remove metal residues from the reaction vessel, so it is preferable to use zinc in the form of a fine powder (zinc dust).

To reduce the induction period of the reaction and the activation of the organometallic complex, it is advisable to add activators to the reaction mass. As such, metal halides can be used, for example, metal iodides, which react with organic complexes of nickel and palladium with the formation of active forms of catalysts; sodium and potassium iodides are most often used for this.

The form of the process for obtaining GFBD in accordance with the invention is not of particular importance. You can carry out the process of dosing chlorotrifluoroethylene in a reaction vessel with a catalyst and collect reaction products at the outlet of a low-temperature trap or pump chlorotrifluoroethylene under pressure into a reaction vessel with a catalyst, keep it closed at the required temperature and collect gaseous products in a low-temperature trap.

Unreacted chlorotrifluoroethylene can be separated from the reaction products and reused in the process. The best method for the separation of reaction products is fractional distillation. For the convenience of working in the laboratory, reaction products can be converted into liquid products at room temperature (for example, bromination), then they are separated by known methods and regenerated.

Embodiments of the invention

The following examples illustrate the possibility of implementing the method for producing HFBD according to the invention, but do not limit it.

Examples No. 1-12

The reaction was carried out in a Schlenk vessel equipped with a glass valve for gas supply and evacuation. To prepare the metal complex catalyst, a ligand and metal iodide as an activator were added to a solution of the complex palladium salt in DMAA. The resulting mixture was purged with chlorotrifluoroethylene (hereinafter referred to as MOH) and the reaction vessel was filled with it, zinc dust was added, and a rubber membrane (hereinafter septum) was closed, into which a 150 ml syringe was inserted to create a reserve of volume for the gas expanding when heated. The reaction vessel was kept in an oil bath at the required temperature and periodically stirred by shaking. Samples of the gas phase were periodically taken over the reaction mixture with a gas syringe, analysis was performed by gas-liquid chromatography with a mass-selective detector.

Reaction conditions and test results are shown in table No. 1.

Example No. 13

In a test tube with a volume of 30 ml in a stream of argon 0.2 mmol of PdCl ₂ (CH ₃ CN) ₂ , 0.6 mmol of tricyclohexylphosphine and 4 ml of DMAA were mixed. The reaction mixture was heated to 100 ° C for 3-5 minutes and cooled to room temperature. To the resulting suspension of the complex was added 0.8 mmol of anhydrous NaI, 200 mg of dry CuI and 3 g of Zn dust. MZ was condensed into a test tube while cooling with liquid nitrogen. The tube was closed with a septum and heated again to 100 ° C, the excess MH was etched through a needle inserted into the septum. During the reaction, the pressure inside the system was maintained using a 25 ml syringe filled with MOH and connected to the reaction vessel through a needle. Samples of the gas phase were periodically taken over the reaction mixture with a gas syringe, analysis was performed by gas-liquid chromatography with a mass-selective detector. In addition to HFBD and TFE, perfluorocyclobutene (hereinafter PFCB) was found in the reaction products. The reaction conditions and the results of the analysis of the reaction products are shown in table No. 2.

Example No. 14

In a 30 ml tube in an argon stream, 0.2 mmol of PdCl ₂ (CH ₃ CN) ₂ , 0.6 mmol of diphenylmethylphosphine and 4 ml of DMAA were mixed. The reaction mixture was heated to 100 ° C for 3-5 minutes and cooled to room temperature. To the resulting suspension of the complex was added 0.8 mmol of anhydrous NaI, 200 mg of dry CuI and 3 g of Zn dust. MZ was condensed into a test tube while cooling with liquid nitrogen. The tube was closed with a septum and heated again to 100 ° C, the excess MH was etched through a needle inserted into the septum. During the reaction, the pressure inside the system was maintained using a 25 ml syringe filled with MOH and connected to the reaction vessel through a needle. Samples of the gas phase were periodically taken over the reaction mixture with a gas syringe, analysis was performed by gas-liquid chromatography with a mass-selective detector. The reaction conditions and the results of the analysis of the reaction products are shown in table No. 2.

Examples No. 15-18

In test tubes purged with argon, the complex nickel salt, ligands, activator were placed, zinc was added and sealed with septa. After that, upon cooling with liquid nitrogen, an excess of MZ was condensed in all tubes and 4 ml of the corresponding solvent was added. After heating, the reaction mixtures were intensively mixed at room temperature (20-25 ° C).

Even when the reaction mixtures were heated, a change in the color of the suspension to red-brown was observed. Moreover, in the experiment with zinc granules, the changes occurred much more slowly. Samples of the gas phase were periodically taken over the reaction mixture with a gas syringe, analysis was performed by gas-liquid chromatography with a mass-selective detector.

The reaction conditions and the results of the analysis of the reaction products are shown in table No. 3.

Example No. 19

6.54 g (PPh ₃ ) ₂ NiCl ₂ (10 mmol), 1.56 g of 2,2'-bipyridyl (10 mmol), 5.24 g were placed in a two-necked flask equipped with an oil seal and connected with a wide outlet to the receiver. triphenylphosphine (hereinafter PPh ₃ ) (20 mmol), 2.69 g of CuCl ₂ (20 mmol), an excess of 40 g of powdered zinc (0.61 mol), 80 ml of DMAA. The reaction mixture was ice-cooled, and the reaction vessel was filled with MOH. The mixture was stirred in the temperature range at room temperature for one day. To collect reaction products, they were blown into a receiver cooled with a dry ice / acetone mixture (temperature range -50-0 ° C). After a day, the receiver was cooled with liquid nitrogen. In this case, both intense condensation of the products and distillation of the solvent under the conditions of the resulting vacuum were observed. The condensate mass was 9.66 g. The condensate was warmed up to room temperature and a gas phase sample was taken for analysis, which showed the following composition: MOH - 88.4%, HFBD - 7.1%, trifluoroethylene (TFE) - 4.5%.

Example No. 20

1.5 g (13 mmol) of liquid MOH was placed in an autoclave with a glass liner, 6 ml of chilled DMAA, 0.25 mmol of PdCl ₂ (PhCN) ₂ , 1 mmol of tris (o-tolyl) phosphine and 9 mmol of KI were added to it. Then added 4 g of zinc dust and 5 g of zinc granules for mixing. The autoclave was closed and heated in an oil bath at 50-60 ° C. Analyzes of gases from the autoclave showed the following results: after 3 hours - 13.8% GFBD + 1% TFE. After 19 hours - 27.2% HFBD + 8.1% TFE + 3.1% heptafluorobutene.

Example No. 21

In a 30 ml test tube in a stream of argon, 0.196 g (0.25 mmol) of PdCl ₂ (o-Tol ₃ P) ₂ and 6 ml of DMAA were mixed. The reaction mixture was heated to 85 ° C. 0.150 g (1 mmol) of NaI was added to the resulting dark yellow suspension. The solution turned brown-violet, it was heated to dissolve (2-3 minutes at 120-130 ° C) and the resulting red-violet solution was cooled to room temperature. Then the tube was purged with MOH and 2 g (30 mmol) of zinc dust was added. The solution for 1-2 minutes already at room temperature turned yellow-orange. The reaction vessel was closed with a rubber septum, into which a syringe containing 100 ml of MOH was inserted through a needle and heated to 60 ° C. Samples of the gas phase were periodically taken over the reaction mixture with a gas syringe, analysis was performed by gas-liquid chromatography with a mass-selective detector. After 1.5 hours, the content of HFBD in the gas phase was 23.3%, the rest of the Ministry of Health.

Thus, as follows from the presented examples, the method according to the invention allows the direct reaction of chlorotrifluoroethylene with zinc to obtain HFBD according to a fairly simple technology.

Table number 1 Example No. Loading Temperature ° C Time h Reaction products The transition metal complex / mol Ligand (L) L / Pd ratio Iodide /, mmol DMAA, ml Zn, mmol MH, ml GFBD,% TFE,% one PdCl ₂ (PhCN) ₂ / 0.25 P (o-CH ₃ C ₆ H ₅ ) ₃ 2 KI / 2.25 6 thirty one hundred 50-60 7 17.00 0.5 2 PdCl ₂ (PhCN) ₂ / 0.25 P (o-CH ₃ C ₆ H ₅ ) ₃ four KI / 2.25 6 thirty one hundred 90-100 one 24.00 0.1 90-100 8 27.70 1.80 3 PdCl ₂ (MeCN) ₂ / 0.5 P (o-CH ₃ C ₆ H ₅ ) ₃ 2 KI / 3,5 6 thirty 40 70 3 22.00 1.00 four PdCl ₂ (PhCN) ₂ / 0.25 P (o-CH ₃ C ₆ H ₅ ) ₃ four 0 6 thirty one hundred 50-60 5 2.00 <0.1 5 PdCl ₂ (PhCN) ₂ / 0.25 P (o-CH ₃ C ₆ H ₅ ) ₃ four KI / 5 6 thirty one hundred 50-60 7 11.00 0.4 6 PdCl ₂ (CH ₃ CN) ₂ / 0.5 P (o-CH ₃ C ₆ H ₅ ) ₃ 2 KI / 3.5 + CuI / 0.75 6 thirty one hundred twenty 24 21.50 1.20 45 5 21.80 3.00 60 5 26.70 6.70 7 PdCl ₂ (CH ₃ CN) ₂ / 0.5 Phenanthroline 2 NaI / 2 + Cul / 1.5 6 thirty 40 70 one 15.40 <0.4 8 PdCl ₂ (CH ₃ CN) ₂ / 0.25 P (o-CH ₃ C ₆ H ₅ ) ₃ four NaI / I 6 thirty 40 70 6 23.80 2,30 9 Pd (dba) * ₂ / 0.1 P (o-CH ₃ C ₆ H ₅ ) ₃ 2 NaI / 0.4 2 fifteen twenty 60 four 15,80 0.80 10 Pd (CH ₃ COO) ₂ / 0.1 P (o-CH ₃ C ₆ H ₅ ) ₃ 2 NaI / 0.4 2 fifteen twenty 60 four 4.70 1.90 eleven PdCl ₂ (PhCN) ₂ / 0.25 P (o-CH ₃ C ₆ H ₅ ) ₃ 2 KI / 0.5 6 thirty one hundred 50-60 2 1.00 <0.1 7 7.00 0.20 fourteen 23.70 2.20 12 PdCl ₂ (PhCN) ₂ / 0.25 P (o-CH ₃ C ₆ H ₅ ) ₃ four KI / 2.25 6 thirty one hundred 50-60 3 9.00 <0.2 22 34.00 3.00 * dba - dibenzylideneacetone

Table number 2 Example No. Ligand Temperature ° C Time h Products GFBD,% TFE,% PFZB 13 Ph ₂ PMe one hundred 2 3.90 11.30 0 5 48.00 48,20 2.9 fourteen (c-C ₆ H ₁₁ ) ₃ P one hundred 2 14.60 2.10 0 5 73.00 10.70 2.6

Table number 3 Example No. Loading Time h Analysis The transition metal complex / mol Ligand Activator / mmol Solvent ml Zn, mmol MH,% GFBD,% TFE,% fifteen NiCl ₂ (PPh ₃ ) ₂ / 0.5 bpy / 0,5 PPh _3/1 CuCl ₂ / 0.25 N-MTD / 4 77 (granules) 26 59.9 22.1 eighteen 48 33,2 23.6 42,2 168 85.1 11.3 3.6 16 NiCl ₂ (PPh ₃ ) ₂ / 0.5 bpy / 0,5 PPh _3/1 CuCl ₂ / 0.25 DMAA / 4 twenty 15,5 83,2 11.6 5.2 24 81.5 11.1 7.4 185.5 67.2 eighteen 14.8 17 (PPh _{3) 2} NiCl _2/10 phen / 0,5 PPh _3/1 CuCl _2/20 DMAA / 4 40 6 86.1 4.4 9.5 eighteen (PPh _{3) 2} NiCl _2/10 phen / 0,5 PPh _3/1 CuCl _2/20 N-MTD / 4 40 6 86 8.3 5.7 bpy - 2,2'-bipyridyl phen - phenanthroline PPh ₃ - triphenylphosphine MZ - chlorotrifluoroethylene

Claims (6)

1. A method of producing hexafluorobutadiene by direct reaction of chlorotrifluoroethylene with zinc in the presence of a metal complex catalyst based on solutions of organic transition metal complexes in polar organic solvents and possibly in the presence of an activating additive, which is used metal halides. 2. The method according to claim 1, characterized in that they use a catalyst formed "in situ" when mixing organic complexes of transition metals with a complexing ligand in a polar organic solvent. 3. The method according to claim 1, characterized in that nickel and palladium compounds are used as organic transition metal complexes. 4. The method according to claim 1, characterized in that metal iodides are used as activating additives. 5. The method according to claim 1, characterized in that the reaction is carried out at a temperature of 20-100 ° C, preferably 50-80 ° C. 6. The method according to claim 1, characterized in that the reaction is carried out with an incomplete conversion of chlorotrifluoroethylene, which, after separation of the reaction products by distillation, is returned to the process.