JP2008201678A - Method for producing 1,1,1,3,3,3-hexafluoro-2-propanone or hydrate of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of producing 1,1,1,3,3,3-hexafluoro-2-propanone or its hydrate without requiring a complex device, under a mild reaction condition and in a high yield. <P>SOLUTION: This method for producing 1,1,1,3,3,3-hexafluoro-2-propanone expressed by chemical formula:(CF<SB>3</SB>)<SB>2</SB>C=O, or its hydrate is provided by reacting a monoetherate of 1,3,3,3-tetrafluoro-2-(trifuloromethyl)-1-propene expressed by general formula (1) [wherein, R is a monovalent hydrocarbon group] with sodium hypochlorite by using water as solvent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing 1,1,1,3,3,3-hexafluoro-2-propanone or a hydrate thereof.

  1,1,1,3,3,3-Hexafluoro-2-propanone is a useful compound as an intermediate raw material for pharmaceuticals and agricultural chemicals, a raw material for synthetic resins, synthetic rubbers and the like.

  Conventionally, 1,1,1,3,3,3-hexafluoro-2-propanone is produced by 1,1,3,3,3-pentafluoro-2- (trifluoromethyl) -1-propene. There are known a method of oxidizing potassium permanganate, a method of reacting hexafluoropropene with Lewis acid, a method of oxidizing hexafluorothioacetone dimer with nitric acid, a method of fluorinating hexachloroacetone, and the like.

  However, the oxidation reaction with potassium permanganate is intense and it is difficult to treat by-products. The method using hexafluoropropene as a raw material has a drawback that it is difficult to obtain a high-purity product. In nitric acid oxidation of hexafluorothioacetone dimer, removal of impurities contained in the obtained 1,1,1,3,3,3-hexafluoro-2-propanone hydrate is complicated. Further, in the fluorination of hexachloroacetone, it is difficult to obtain a high-purity product, and it is necessary to use harmful antimony pentachloride as a catalyst.

  In view of these points, various studies have been conducted on methods for producing 1,1,1,3,3,3-hexafluoro-2-propanone. Heptabenyl isobutyl ether is used as a raw material and oxygen and under light irradiation. A method of reaction, a method of ozone oxidation, a method of thermal decomposition in the presence of oxygen and an activated carbon catalyst, and the like have been proposed (see Patent Documents 1 to 3 below).

However, even with these methods, it is difficult to obtain the target product in a high yield, and ozone generation and light irradiation are necessary, and there is a disadvantage that the apparatus becomes complicated for mass production.
JP-A-61-277645 JP-A-64-26527 Japanese Unexamined Patent Publication No. 1-203339

  The present invention has been made in view of the above-mentioned problems of the prior art, and the main purpose thereof is 1,1,1,3,3,3-hexafluoro-2-propanone or a hydrate thereof. An object of the present invention is to provide a method which can be produced in a high yield under mild reaction conditions without requiring a complicated apparatus.

  As a result of intensive studies to achieve the above-mentioned object, the present inventor used 1,3-etherified product of 1,3,3,3-tetrafluoro-2- (trifluoromethyl) -1-propene as a raw material, According to the method in which water is reacted with sodium nitrite as a solvent, the desired 1,1,1,3,3,3-hexafluoro-2-phenyl is obtained with good selectivity under relatively mild reaction conditions. It has been found that propanone or a hydrate thereof can be produced, and the present invention has been completed here.

That is, the present invention provides a method for producing the following 1,1,1,3,3,3-hexafluoro-2-propanone or a hydrate thereof.
1. Using water as a solvent, the general formula (1)

(Wherein R is a monovalent hydrocarbon group) 1,3-, 3-tetrafluoro-2- (trifluoromethyl) -1-propene represented by Chemical formula characterized by reacting with sodium acid

The manufacturing method of 1,1,1,3,3,3-hexafluoro-2-propanone represented by these, or its hydrate.
2. Item 2. The method according to Item 1, wherein in General Formula (1), R is a lower alkyl group, an aryl group, or an aralkyl group.
3. It is characterized by adding an aqueous solution of sodium chlorite to 1-etherified product of 3,3,3-tetrafluoro-2- (trifluoromethyl) -1-propene represented by the general formula (1) Item 3. The method according to Item 1 or 2 above.
4). The method according to any one of Items 1 to 3, wherein the reaction is further performed in the presence of an alkali metal carbonate.

  In the present invention, as a raw material, the following general formula (1)

A 1-etherified product of 1,3,3,3-tetrafluoro-2- (trifluoromethyl) -1-propene represented by the formula (wherein R is a monovalent hydrocarbon group) is used.

  In the compound represented by the general formula (1), R is a monovalent hydrocarbon group. Specific examples of the monovalent hydrocarbon group in the general formula (1) include a straight chain or branched chain having about 1 to 4 carbon atoms such as methyl, ethyl, 1-propyl, 2-propyl, 1-butyl and the like. A lower alkyl group; an aryl group such as a phenyl group; and an aralkyl group such as a benzyl group.

  The compound of the above general formula (1) is a known substance, for example, 1,1,3,3,3-pentafluoro-2- () obtained as a by-product during the production of hexafluoropropylene, which is a raw material for fluororesin. Trifluoromethyl) -1-propene can be produced as a starting material in the following steps.

  That is, 1,1,3,3,3-pentafluoro-2- (trifluoromethyl) -1-propene is produced according to the following reaction formula: lower alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1 -Easy to form adducts with butanol and the like.

  Next, 2- (difluoro (alkoxy) methyl) -1,1,1,3,3,3-hexafluoropropane, which is the alcohol adduct described above, is dehydrofluorinated in the presence of a phase transfer catalyst. According to the following reaction formula, 1,3,3,3-tetrafluoro-1-alkoxy-2- (trifluoromethyl) -1-propene is formed.

  In the method of the present invention, by reacting the compound represented by the general formula (1) with sodium chlorite using water as a solvent, the following chemical formula:

1,1,1,3,3,3-hexafluoro-2-propanone or a hydrate thereof can be obtained.

  In the above reaction, the amount of sodium chlorite used is preferably about 1 to 2 mol, more preferably about 1 to 1.5 mol, relative to 1 mol of the compound of the general formula (1) as a raw material. .

  As a reaction method, the compound represented by the general formula (1) and sodium chlorite may be simultaneously added to water, but usually an aqueous solution in which sodium chlorite is dissolved is represented by the general formula (1). What is necessary is just to add to the compound made.

  The amount of water used is not particularly limited, but usually the amount of sodium chlorite may be about 10 to 50% by weight, and preferably about 25 to 50% by weight. .

  The reaction temperature may be about 0 to 80 ° C. In particular, when the reaction temperature is about 0 to 50 ° C., the target product can be obtained with high yield.

  The reaction time is usually about 30 minutes to 48 hours.

  Furthermore, in the production method of the present invention, the hydrogen fluoride generated can be neutralized by performing the reaction in the presence of an alkali metal carbonate such as sodium carbonate or potassium carbonate. What is necessary is just to melt | dissolve an alkali metal carbonate in water which is a reaction solvent, and the usage-amount should just be about 0.1-2 mol with respect to 1 mol of compounds of General formula (1) used as a raw material, etc. It is preferable to be about a mole.

  Further, as described above, 1,3,3,3-tetrafluoro-1-alkoxy-2- (trifluoromethyl) -1-propene is 2- (difluoro (alkoxy) methyl) in the presence of a phase transfer catalyst. It is produced by dehydrofluorination by the reaction of -1,1,1,3,3,3-hexafluoropropane and alkali metal or alkaline earth metal carbonate or hydroxide. Therefore, dehydrofluorination using 2- (difluoro (alkoxy) methyl) -1,1,1,3,3,3-hexafluoropropane as a raw material by the presence of sodium chlorite during this reaction The reaction and the oxidation reaction are allowed to proceed simultaneously to obtain 1,1,1,3,3,3-hexafluoro-2-propanone or a hydrate thereof. Thereby, the reaction process can be shortened.

  According to the production method of the present invention described above, a hydrate such as 1,1,1,3,3,3-hexafluoro-2-propanone trihydrate is usually obtained. The obtained hydrate is dried using, for example, anhydrous calcium chloride, and then dehydrated with concentrated sulfuric acid to obtain 1,1,1,3,3,3-hexafluoro-2-propanone anhydride. Can be obtained.

  1,1,1,3,3,3-hexafluoro-2-propanone or a hydrate thereof obtained by the production method of the present invention can be separated and purified by a known method. For example, it can be purified by a method such as distillation or extraction.

  According to the method of the present invention, a complex apparatus using a 1-etherified product of 1,3,3,3-tetrafluoro-2- (trifluoromethyl) -1-propene represented by the general formula (1) as a raw material Thus, 1,1,3,3,3-hexafluoro-2-propanone or a hydrate thereof can be obtained in a high yield under relatively mild reaction conditions.

  Further, the method of the present invention effectively uses 1,1,3,3,3-pentafluoro-2- (trifluoromethyl) -1-propene or an alcohol adduct thereof, which is a by-product during the production of hexafluoropropylene. From this point of view, it is a highly useful method.

  Hereinafter, the present invention will be described in more detail with reference to examples.

  Example 1

  To a 50 ml three-necked flask equipped with a dry ice-acetone trap, 2.1 g (10 mmol) of 1,3,3,3-tetrafluoro-1-methoxy-2- (trifluoromethyl) -1-propene (hereinafter abbreviated as HIME) Then, a solution of sodium chlorite 1.4 g (12 mmol) (manufactured by Wako Pure Chemical Industries, Ltd.) dissolved in 5 ml of water was gradually added dropwise with stirring on ice. After completion of the dropwise addition, the temperature was raised to room temperature, and the temperature was gradually raised while stirring to 70 ° C. over 30 minutes.

It changed from the two-layer (lower layer: HIME, upper layer: sodium chlorite water) system to a homogeneous mixture in which white crystals were precipitated. The pH of the mixture was about 2. After cooling to room temperature, trifluoroethanol CF ₃ CH ₂ OH (1.0 g; 10 mmol) was added to the reaction mixture, and the product was quantified by an internal standard method ¹⁹ F-NMR analysis to obtain 1,1,1,3,3 The formation of 3-hexafluoro-2-propanone trihydrate was confirmed. Yield 82.4% (yield 1.52 g).
¹⁹ F-NMR (CD ₃ COCD ₃ ; CFCl ₃ ): δ -55.7 (m, 0.069 × 3F, CF ₃ (HIME)), -56.6 (m, 0.069 × 3F, CF ₃ (HIME)), -75.9 ( t, 3F, CF ₃ CH ₂ ), -81.4 (s, 0.824 × 6F, CF ₃ COCF ₃ · H ₂ O), -174 (s, 0.64F, HF).

  Example 2

  To a 50 ml three-necked flask equipped with a dry ice-acetone trap, 4.2 g (20 mmol) of HIME was added, and while stirring at 40-50 ° C., 1.4 g (10 mmol) of potassium carbonate (made by Kishida Chemical) and A solution in which 2.8 g (20 mmol) of sodium chlorate (Wako Pure Chemical Industries) was dissolved was gradually added dropwise. After completion of dropping, the mixture was stirred at 50 ° C. for 3 hours.

It changed from the two-layer (lower layer: HIME, upper layer: sodium chlorite water) system to a homogeneous mixture in which white crystals were precipitated. The pH of the mixture was about 8.5. After cooling to room temperature, CF ₃ CH ₂ OH (1.0 g; 10 mmol) was added to the reaction mixture, and the product was quantified by an internal standard method ¹⁹ F-NMR analysis to obtain 1,1,1,3,3,3- Formation of hexafluoro-2-propanone trihydrate was confirmed. Yield 92.9% (Yield 3.39g)
¹⁹ F-NMR (CD ₃ COCD ₃ ; CFCl3): δ -55.7 (m, 0.077 × 3 × 2F, CF ₃ (HIME)), -56.6 (m, 0.077 × 3 × 2F, CF ₃ (HIME)), -75.9 (t, 3F, CF ₃ CH ₂ ), -81.4 (s, 0.929 × 6 × 2F, CF ₃ COCF ₃・ H ₂ O)

Claims (4)

Using water as a solvent, the general formula (1)

(Wherein R is a monovalent hydrocarbon group) 1,3-, 3-tetrafluoro-2- (trifluoromethyl) -1-propene represented by Chemical formula characterized by reacting with sodium acid

The manufacturing method of 1,1,1,3,3,3-hexafluoro-2-propanone represented by these, or its hydrate. The method according to claim 1, wherein R in the general formula (1) is a lower alkyl group, an aryl group or an aralkyl group. It is characterized by adding an aqueous solution of sodium chlorite to 1-etherified product of 3,3,3-tetrafluoro-2- (trifluoromethyl) -1-propene represented by the general formula (1) The method according to claim 1 or 2. Furthermore, the method in any one of Claims 1-3 which reacts in presence of alkali metal carbonate.