RU2484081C2 - Method of producing acyl fluoride of difluoro(fluorosulphate)acetic acid - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing an acyl fluoride of difluoro(fluorosulphate)acetic acid while heating perfluoroallyl fluorosulphate in a reactor to temperature of 175-220°C, feeding oxygen into the reactor in an amount which exceeds the calculated amount for oxidation of the perfluoroallyl fluorosulphate double bond by 2-5 times, and holding the reaction mixture at temperature of 175-220°C for 2-5 hours.

EFFECT: method is simple, is realised in a single step, enables to obtain a pure end product with high output and does not require a long process.

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Description

The present invention relates to the field of obtaining organofluorine compounds of the formula

FO ₂ SOCF ₂ COF,

which can be used as an intermediate for the preparation of organofluorine functional modifying monomers for thermally aggressive organofluorine polymers. The present invention can be used in the production of synthetic rubbers.

A known method of producing fluoride hydride difluoro (fluorosulfate) acetic acid [US Pat. of. 4,460,512, publ. 07.17.1984], which consists in the fact that first, by the reaction of potassium chloride and fluorosulfonic acid, an electrolyte is prepared. In this case, hydrochloric acid is released and there is a foam. The resulting solution with the help of dry nitrogen is purified from the remains of hydrochloric acid and pre-electrolyzed for 3-5 hours. Next, difluoroacetyl fluoride is fed into the electrolytic medium for 12 hours with stirring (25-30 ° C, 8A), then fluorosulfonic acid is added and electrolysis is carried out for another 12 hours, raising the voltage. The reaction product with a boiling point of 40-42 ° C is isolated on a distillation column 0.5 m long. The product contains 13% fluorosulfonic acid and 87% difluoro (fluorosulfate) acetic acid. The yield relative to difluoroacetyl fluoride is 77% of theoretical. The disadvantages of this method are the multi-stage process time and the difficulty of obtaining a pure product: the finished product contains 13% fluorosulfonic acid, which is an extremely aggressive compound, and loss of product during separation will reduce its yield. In addition, the electrolytic process requires expensive equipment and is quite dangerous for the environment.

The closest in technical essence the method of producing difluoro (fluorosulphate) of acetic acid is the method described in [Lebedev N.V., Berenblit V.V., Troichanskaya P.E., Gubanov V.A. Housing and communal services. 2009.V.28. Issue 3 Pages 455-461]. In this work, perfluoroallyl fluorosulfate oxide is first prepared according to the method of [JP 01163173, Publication Date: 06/27/1989), namely, perfluoroallyl fluorosulfate is oxidized with oxygen in a molar ratio of 1: 2-3: 1 at 30-40 ° C. Then, perfluoroallyl fluorosulfate oxide is added to the reaction mixture containing potassium fluoride, ethylene glycol and acetonitrile in a stream of nitrogen. Then, while heating and stirring, the mixture is boiled, decomposition products are condensed in a trap (-80 ÷ -90 ° С). According to ¹⁹ F NMR spectroscopy, 0.5% of the desired product is formed in the trap. The ¹⁹ F NMR spectrum contained 3 signals from the groups: FSO ₂ (+50.2 ppm, ⁴ J = 7.6 Hz), COF (+15.8 ppm, ³ J = 2.5 Hz, OCF ₂ (-76.4 ppm, ³ J = 2.5 Hz). The disadvantages of this method are the low yield of the target product and the complexity of its cleaning.

The objective of this invention is to develop a method for producing fluoride hydrofluoride (fluorosulfate) acetic acid, which allows to obtain the target product of high purity with high yield in a short period of time.

The task is achieved in that the perfluoroallyl fluorosulfate is preheated to 175-220 ° C, and oxygen is supplied in an amount exceeding the calculated for the oxidation of the double bond of perfluoroallyl fluorosulfate by 2-5 times, and the process is carried out with subsequent exposure of the reaction mass at this temperature.

The essence of the invention consists in the following: perfluoroallyl fluorosulfate is heated in the reactor to 175-220 ° C, after which oxygen is supplied to the reactor in an amount exceeding the calculated value for oxidation of the double bond of perfluoroallyl fluorosulfate by 2-5 times. After the end of the oxygen supply, the reaction mixture was kept at a temperature of 175-220 ° C for 2-5 hours. Next, the reaction mixture is subjected to distillation to isolate the target product. The structure of the obtained compound is confirmed by elemental analysis data, as well as ¹⁹ F and ¹³ C NMR spectroscopy. NMR spectra were recorded on a Bruker Spectrospin AM 500 instrument.

The invention is illustrated by the following examples.

Example 1

The process is carried out in a laboratory autoclave equipped with a jacket with a capacity of 1.2 liters. The autoclave, in which a vacuum is created, is filled with perfluoroallyl fluorosulfate (230 g). The reactor is heated to a temperature of 185 ° C, after which the supply of oxygen in an amount exceeding the calculated for oxidation of the double bond of perfluoroallyl fluorosulfate by 2 times (64 g) is started. The reaction is carried out at a temperature of 185-190 ° C for 2 hours. As the reaction proceeds, the temperature rise is removed by the refrigerant circulating in the jacket. After the reaction, the autoclave is kept at the reaction temperature for 2 hours. After isolation of the desired product by distillation, the yield of the compound FO ₂ SOCF ₂ COF is 80% (157 g) based on the starting perfluoroallyl fluorosulfate. The boiling point of the compound FO ₂ SOCF ₂ COF is 39.4 ° C.

Elemental analysis data, found (calculated): C-12.4 (12.25), F-37.9 (38.76), O-31.5 (32.64), S-18.2 (16, 35).

The ¹⁹ F NMR spectrum contains 3 signals from the groups: FSO ₂ (+50.0 ppm, td, ⁴ J = 7.3 Hz, ⁵ J = 0.8 Hz), COF (+15.6 ppm) , td, ³ J = 2.9 Hz, ⁵ J = 0.8 Hz, OCF ₂ (-77.5 ppm, dd, ⁴ J = 7.3 Hz and ³ J = 2.9 Hz).

The ¹³ C NMR spectrum contains 2 signals from the groups: OCF ₂ - (+111.7 ppm, tdd, ¹ J = 289.4 Hz, ² J = 94.8 Hz, ³ J = 1.45 Hz) and -COF (+146.0 ppm, dtd, ¹ J = 372.85 Hz, ² J = 44.5 Hz, ⁴ J = 1.45 Hz).

According to the analysis, the target product corresponds to the formula of the compound FO ₂ SOCF ₂ COF.

Example 2

Under the conditions of example 1, a 3.2-fold excess of oxygen (102.4 g) was fed into the reactor heated to a temperature of 175 ° C and the oxidation reaction was carried out for 2.5 hours at a temperature of 175-180 ° C. As the reaction proceeds, the temperature rise is removed by the refrigerant circulating in the jacket. After the reaction, the autoclave is kept at the reaction temperature for 4 hours. The yield of the compound FO ₂ SOCF ₂ COF is 73% (144 g) based on the starting perfluoroallyl fluorosulfate. The boiling point of the compound FO ₂ SOCF ₂ COF is 39.4 ° C.

Elemental analysis data, found (calculated): C-13.5 (12.25), F-37.4 (38.76), O-33.3 (32.64), S-15.8 (16, 35).

The ¹⁹ F NMR spectrum contains 3 signals from the groups: FSO ₂ (+50.1 ppm, td, ⁴ J = 7.3 Hz, ⁵ J = 0.8 Hz), COF (+15.8 ppm , td, ³ J = 2.9 Hz, ⁵ J = 0.8 Hz, OCF ₂ (-77.6 ppm, dd, ⁴ J = 7.3 Hz and ³ J = 2.9 Hz).

The ¹³ C NMR spectrum contains 2 signals from the groups: OCF ₂ - (+111.9 ppm, tdd, ¹ J = 289.35 Hz, ² J = 94.8 Hz, ³ J = 1.45 Hz) and -COF (+146.2 ppm, dtd, ¹ J = 372.85 Hz, ² J = 44.5 Hz, ⁴ J = 1.45 Hz).

According to the analysis, the target product corresponds to the formula of the compound FO ₂ SOCF ₂ COF.

Example 3

Under the conditions of example 1, a 4-fold excess of oxygen (128 g) was fed into the reactor heated to a temperature of 185 ° C and the oxidation reaction was carried out for 4 hours at a temperature of 185-190 ° C. As the reaction proceeds, the temperature rise is removed by the refrigerant circulating in the jacket. After the reaction, the autoclave is kept at the reaction temperature for 5 hours. The yield of the compound FO ₂ SOCF ₂ COF is 95% (186 g) based on the starting perfluoroallyl fluorosulfate. The boiling point of the compound FO ₂ SOCF ₂ COF is 39.4 ° C.

Elemental analysis data, found (calculated): C-14.0 (12.25), F-36.4 (38.76), O-33.8 (32.64), S-15.7 (16, 35).

The ¹⁹ F NMR spectrum contains 3 signals from the groups: FSO ₂ (+49.5 ppm, td, ⁴ J = 7.3 Hz, ⁵ J = -0.8 Hz), COF (+14.5 ppm ., td, ³ J = 2.9 Hz, ⁵ J = 0.8 Hz, OCF ₂ (-76.9 ppm, dd, ⁴ J = 7.3 Hz and ³ J = 2.9 Hz) .

The ¹³ C NMR spectrum contains 2 signals from the groups: OCF ₂ - (+111.3 ppm, tdd, ¹ J = 289.35 Hz, ² J = 94.8 Hz, ³ J = 1.45 Hz) and -COF (+145.4 ppm, ddd, ¹ J = 372.85 Hz, ² J = 44.5 Hz, ⁴ J = 1.45 Hz).

According to the analysis, the target product corresponds to the formula of the compound FO ₂ SOCF ₂ COF.

Example 4

Under the conditions of Example 1, a 5-fold excess of oxygen (160 g) was fed into a reactor heated to a temperature of 220 ° C and the oxidation reaction was carried out for 4 hours at a temperature of 210-220 ° C. As the reaction proceeds, the temperature rise is removed by the refrigerant circulating in the jacket. After the reaction, the autoclave is kept at the reaction temperature for 3 hours. The yield of the compound FO ₂ SOCF ₂ COF is 97% (190 g) based on the starting perfluoroallyl fluorosulfate. The boiling point of the compound FO ₂ SOCF ₂ COF is 39.4 ° C.

Elemental analysis data, found (calculated): C-14.0 (12.25), F-36.4 (38.76), O-33.8 (32.64), S-15.7 (16, 35).

The ¹⁹ F NMR spectrum contains 3 signals from the groups: FSO ₂ (+49.5 ppm, td, ⁴ J = 7.3 Hz, ⁵ J = 0.8 Hz), COF (+14.5 ppm , td. ³ J = 2.9 Hz, ⁵ J = 0.8 Hz, OCF ₂ (-76.9 ppm. dd, ⁴ J = 7.3 Hz and ³ J = 2.9 Hz).

The ¹³ C NMR spectrum contains 2 signals from the groups: OCF ₂ - (+111.3 ppm, tdd, ¹ J = 289.35 Hz, ² J = 94.8 Hz, ³ J = 1.45 Hz) and -COF (+145.4 ppm, ddd, ¹ J = 372.85 Hz, ² J = 44.5 Hz, ⁴ J = 1.45 Hz).

According to the analysis, the target product corresponds to the formula of the compound FO ₂ SOCF ₂ COF.

Thus, the proposed method for the synthesis of compounds FOCCF ₂ COF is technologically simple, practically carried out in one stage and allows you to get a clean target product with high yield. It does not require a long process.

Claims (1)

A method of producing difluoro (fluorosulphate) acetic acid fluoride by oxidizing perfluoroallyl fluorosulphate with oxygen at an elevated temperature, which means that perfluoroallyl fluorosulphate is preheated to 175-220 ° C, and oxygen is supplied in an amount exceeding that calculated for oxidation of the double bond of perfluoroallyl fluorosulphate in 2 , and the process is carried out with subsequent exposure of the reaction mass at a given temperature.