CS264099B1 - A method for preparing chlorofluoropropionyl fluorides - Google Patents

Abstract

The solution consists in preparing chlorofluoropropionyl fluorides of the general formula C2CV(3-ar20?> where a is 1 to 3, containing 50 to 90% of the main isomer of the general formula CPXY-CCLP-COP, X and Y are chlorine or fluorine atoms. The desired purpose is achieved by fluorinating chlorofluoropropionyl chlorides, prepared in two stages by the addition of trichlorofluoromethane to 1,2-dichlorodifluoroethene or chlorotrifluoroethene in the presence of aluminum chloride as a catalyst and by reacting the resulting chlorofluoropropions with oleum or sulfur trioxide. The fluorination is carried out with alkali metal fluoride, preferably sodium fluoride and/or potassium fluoride, in an environment of aliphatic nitriles or dinitriles containing 2 to 6 carbon atoms or polyethers containing 1 to 4 ethylene glycols. units, at a temperature of 20 to 200 °C and a pressure of 100 to 1000 kPa.

Description

The present invention relates to a process for the preparation of chlorofluoropropionyl fluorides of the general formula ^C 2 ^Cl and ^F (5-af ^COF 'wherein a is from 1 to 3 containing from 50 to 98% of the main isomer of the formula

CFXY-CC1F-C0F wherein X and Ϊ is chlorine or fluorine, fluorinating the formula chlorfluorpropionylchioridů ° ^C1 and ^P 2 to I5-a) - ^COC1 wherein a is 1 to 3 prepared in two stages trichlorofluoromethane addition to ethene of the formula

CC 1 F · CF 2, where Z is a chlorine or fluorine atom, under the catalytic action of aluminum chloride and the reaction of the resulting chlorofluoropropane of the formula ^C 3 ^C1 b ^F (8-b) where b is 4 or 5, with oleum or sulfur trioxide;

Chlorofluoropropionyl fluorides having an internal chlorofluoromethylene group are prepared by synthetic procedures, depending on their structure.

2-Chlorotetrafluoropropionyl fluoride is prepared from hexafluoropropene by direct reaction with chromyl chloride or a two-step process via halogenated fluorosulfate.

2,3-Dichlorfrifluorpropionylí’luoride is being prepared

264,099 from hexafluoropropene by a three-step process involving the addition of methanol. pyrolysis of the resulting product with sodium fluoride and subsequent chlorination of trifluoroacryloyl fluoride. Alternatively, the trifluoroacryloyl fluoride intermediate of this synthesis can be prepared by pyrolysis of the anhydride or sodium salt of tetrafluoro succinic acid.

2,2,3-Trichlorodifluoropropionyl fluoride has been found in small quantities as a by-product in the oxidation of 1,1,3-trichlorotrifluoro-1-propene.

These processes have certain disadvantages. Hexafluoropropene and tetrafluorosuccinic acid derivatives have a relatively high cost. Pyrolytic processes are energy-intensive and produce toxic by-products. 2,2,3-Trichlorodifluoropropionyl fluoride is difficult to separate from the main oxidation product.

According to the invention, these disadvantages are overcome by the process for preparing chlorofluoropropionyl fluorides of the general formula

C ₉ Clřz _K-CGF, 2 (5-a) a 'wherein a is 1 to 3, comprising 50 to 98% of the main isomer of the formula

CFXY-CC1F-COF, where X and Y are chlorine or fluorine atoms, by fluorination of chlorofluoropropionyl chlorides of formula

C _O C1 F, _R-COCl, and (5-a) a 'wherein a is 1 to 3 prepared in two stages trichlorofluoromethane addition to ethene of the formula

CCl 2 CCF 2 where Z is a chlorine or fluorine atom under catalytic action

264 099 aluminum chloride and the reaction of the resulting chlorofluoropropane of general formula. ^C 3 ^C1 b ^F (8-b) 'where b is 4 or 5, with oleic or sulfur trioxide, characterized in that the fluorination is carried out with an alkali metal fluoride in an aliphatic nitrile or dinitrile containing 2 to 6 carbon atoms or polyether containing 1-4 ethylene glycol units, at a temperature of 20 to 200 ¾ and a pressure of 100 to 1000 kPa.

Sodium fluoride and / or potassium fluoride is preferred. The advantages of the preparation process are mainly that the entire synthesis is carried out in three reaction stages, starting with domestic industrially manufactured substances, which are more cost-effective compared to hexafluoropropene or tetrafluorosuccinic acid derivatives. All reaction steps can be carried out in a conventional glass apparatus at atmospheric pressure. Isomeric impurities present in addition to the major isomers in an amount of 2 to 50% do not prevent the synthetic utilization of the major isomers due to different reactivity.

Chlorofluoropropionyl fluorides are used as acylating or alkoxidizing agents analogous to fully fluorinated acyl fluorides and are used as intermediates for the preparation of fluorinated polymers. Some of these, for example 2,3-dichlorotrifluoropropionyl fluoride, can be used for the synthesis of fluorinated ion exchange materials.

The process according to the invention is further described in several exemplary embodiments.

Example 1

A stirred 250 ml flask equipped with a dropping funnel and a 20 cm Vigreux rectifying head column was charged with 40 ml acetonitrile, 25 g potassium fluoride and

50.8 g of dichlorotrifluoropropionyl chloride, prepared by adding 116 g of trichlorofluoromethane to 84 g of 1,2-dichlorodifluoroethene

264 099 in the presence of 12 g of aluminum chloride and 12 g of carbon tetrachloride, followed by the reaction of 106 g of the pentachlorotrifluoropropane thus obtained with 73 ml of 20% ol. The mixture was heated at 100 ° C for 16 h under stirring. to 58 ° C, which fractionated to give 40.8 g of dichlorotrifluoropropionyl fluoride containing 88% of the major isomer, 2,3-dichlorotrifluoropropionyl fluoride, 8% 2,2-dichlorotrifluoropropionyl fluoride and 4%

3,3-dichlorotrifluoropropionyl fluoride

Example 2

40 ml of diethylene glycol dimethyl ether, 25 g of sodium fluoride and 47 g of chlorotetrafluoropropionyl chloride, prepared by the addition of 94 g of trichlorofluoromethane to 63 g of chlorotrifluorethene in the presence of 10 g of aluminum chloride and 10 ml of carbon tetrachloride, were added to the stirred autoclave at -20 ° C. ml olea 35%. The mixture was heated to 30 ° C, the pressure rising from the initial 100 kPa to 450 kPa. After cooling the autoclave to 0 ° C, the crude reaction mixture was fractionated to give 36.1 g of chlorotetrafluoropropionyl fluoride containing 56% of the major isomer, 2-chlorotetrafluoropropionyl fluoride and 44% of 3-chlorotetrafluoropropionyl fluoride.

Example 3

30 ml of adiponitrile, 32 g of sodium fluoride and 57.4 g of trichlorodifluoropropionyl chloride, obtained as a side fraction from diehlortrifluoropropionyl chloride fractionation, prepared analogously to the procedure described in Example 4, were introduced into the apparatus of Example 1. Ss; was heated at 120 ° C for 4 hours under stirring at 100 kPa and 160 ° C for 2 hours while continuously collecting a b.p. 78-90 ° C. Fractionation of the crude product yielded 34.5 g of trichlorodoxfluoropropionyl fluoride. containing 86% of the major isomer, 2,3,3-trichlorodifluoroproponylfluoride and 14%

2,2,3-trichlorodifluoropropionyl fluoride.

Claims (2)

Ρ β E THE CHILD OF THE INVENTION 264 099 1. A process for the preparation of Chloe ^ fluorpropionylfluoridů vzoreo ^{C2 O1} aŮ5- _e) - ^Offl 'wherein a is 1 to 3, comprising 50 to 98% of the main isomer of the formula CFXY-CC1F-COF, where X and Y are chlorine or fluorine atoms, by fluorination of chlorofluoropropionyl chlorides of formula C.CIP 1, -COOl, 2 and V5-a) kde where a is from 1 to 3, prepared in two steps by addition of trichlorofluoromethane to the halenethene of general formula CC1F = CPZ, where Z is a chlorine or fluorine atom, under the catalytic action of aluminum chloride and reacting the chlorfluoropropane of the formula ^G 3 ^C1 b ^F (8-b) so formed where b is 4 or 5, with oleum or sulfur trioxide, characterized by in that the fluorination is carried out with an alkali metal fluoride in an environment of aliphatic nitriles or dinitriles containing 2 or 6 carbon atoms or 1 or 4 ethoxy units, at a pressure of 100 to 1000 kPa. ethers having a temperature of 20 to 200 ° C 2. A process according to claim 1, wherein the alkali metal fluoride is sodium fluoride and / or potassium fluoride.