JP2008273862A - Method for producing 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropanoic acid ester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing, in a high yield, a 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropanoic acid ester which is expressed by the general formula: (CF<SB>3</SB>)<SB>2</SB>C(OH)COOR, in a high yield and is free from the problem of waste material treatment. <P>SOLUTION: Provided is a method for producing 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropanoic acid by hydrolyzing 2-fluoro-2-alkoxy-3,3-bis(trifluoromethyl)oxyrane expressed by general formula shown below [wherein, R is phenyl, benzyl or a 1-12C alkyl] under an acidic condition. The hydrolysis under the acidic condition is performed in the presence of an aqueous solution of hydrofluoric acid, hydrochloric acid, etc. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a process for producing 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropanoic acid (propionic acid) ester. More specifically, the present invention relates to a method for producing 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropanoic acid ester using heptafluoroisobutenyl alkyl ether as a raw material.

As a method for producing 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropanoic acid ester, which is used as a raw material and intermediates in the field of electronic materials, pharmaceuticals, agricultural chemicals and organic synthesis, etc., conventionally, Proposed to oxidatively cleave heptafluoroisobutenyl alkyl ether obtained by dehydrofluorination with octafluoroisobutene produced as a by-product during the production of fluoropropene, followed by dehydrofluorination with potassium permanganate or hydrogen peroxide Has been. However, when potassium permanganate is used, there is a problem in the treatment of manganese dioxide as a by-product, and the method using hydrogen peroxide has a problem that the yield is low.
Izv Akad.Nauk SSSR Ser.Khim., 2 387 (1974) Japanese Patent Publication No. 3-015619

In addition, methods have been proposed in which heptafluoroisobutenyl alkyl ether is reacted with a ruthenium compound or an osmium compound to undergo oxidative cleavage, but these are highly toxic. Environmental impact, waste disposal issues remain
JP 2002-234860 A

An object of the present invention is to have 3,3,3-trifluoro-2-hydroxy-2-trifluoro represented by the general formula (CF ₃ ) ₂ C (OH) COOR without having the problem of waste disposal It is an object of the present invention to provide a method that enables production of methyl propanoic acid ester with high yield.

(ここで、Rはフェニル基、ベンジル基または炭素数1〜12のアルキル基である)で表される2-フルオロ-2-アルコキシ-3,3-ビス(トリフルオロメチル)オキシランを酸性条件下で加水分解することによって達成される。 The object of the present invention is to provide a general formula

(Wherein R is a phenyl group, a benzyl group or an alkyl group having 1 to 12 carbon atoms) 2-fluoro-2-alkoxy-3,3-bis (trifluoromethyl) oxirane represented by acidic conditions This is accomplished by hydrolysis with

  According to the method of the present invention, 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropanoic acid ester can be produced in a high yield without causing problems such as handling of by-products or toxic substances. It has excellent effects such as enabling production.

(R：フェニル基、ベンジル基、炭素数1〜12の鎖状または環状のアルキル基)で表され、これは一般式(CF₃)₂C=CFORで表されるヘプタフルオロイソブテニルアルキルエーテルをオゾンを用いて酸化することにより得ることができる。ここで、ヘプタフルオロイソブテニルエーテルは、ヘキサフルオロプロペン製造時に副生するオクタフルオロイソブテン(CF₃)₂C=CF₂に脂肪族アルコール類、フエノール類またはベンジルアルコールを付加した後、四級アンモニウム塩などの相関移動触媒の存在下、アルカリ金属、アルカリ土類金属の水酸化物、その炭酸塩またはトリアルキルアミンなどの塩基により脱フッ化水素化することにより得ることができる
特許第３，８２３，３３９号公報 The raw material 2-fluoro-2-alkoxy-3,3-bis (trifluoromethyl) oxirane has the general formula

(R: phenyl group, benzyl group, linear or cyclic alkyl group having 1 to 12 carbon atoms), which is a heptafluoroisobutenyl alkyl ether represented by the general formula (CF ₃ ) ₂ C = CFOR Can be obtained by oxidizing with ozone. Here, heptafluoroisobutenyl ether is obtained by adding aliphatic alcohols, phenols or benzyl alcohol to octafluoroisobutene (CF ₃ ) ₂ C = CF ₂ produced as a by-product during the production of hexafluoropropene, and then adding quaternary ammonium. It can be obtained by dehydrofluorination with a base such as an alkali metal, alkaline earth metal hydroxide, carbonate thereof or trialkylamine in the presence of a phase transfer catalyst such as a salt.
Japanese Patent No. 3,823,339

  3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropanoic acid ester hydrolyzes 2-fluoro-2-alkoxy-3,3-bis (trifluoromethyl) oxirane under acidic conditions Can be obtained. The acid used for the acidic condition is not particularly limited as long as it is an aqueous solution, but hydrofluoric acid, hydrochloric acid, sulfuric acid, and the like are used in an aqueous solution from the viewpoint of safety and cost. Specifically, an aqueous solution of about 10 to 30% by weight for hydrofluoric acid, a concentrated hydrochloric acid of 10 to 37% by weight for hydrochloric acid, and an aqueous solution of about 10 to 75% by weight for sulfuric acid, preferably 20 About wt% hydrofluoric acid or about 75 wt% sulfuric acid is used. The use ratio is preferably equal to or less than an equimolar amount with respect to the oxirane compound.

  In the hydrolysis reaction, a phase transfer catalyst can be used from the viewpoint of compatibility with 2-fluoro-2-alkoxy-3,3-bis (trifluoromethyl) oxirane and an acidic aqueous solution. As the phase transfer catalyst, quaternary ammonium salts such as benzyltriethylammonium chloride and tetrabutylmethylammonium bromide are used.

  Moreover, the temperature of a hydrolysis reaction can take a wide temperature from room temperature to about 100 degreeC, and it is possible to obtain sufficient reaction rate also at room temperature.

  The hydrolysis reaction proceeds by mixing and stirring 2-fluoro-2-alkoxy-3,3-bis (trifluoromethyl) oxirane in an acidic aqueous solution. The product 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropanoic acid ester is usually separated and the crude product can be recovered from the lower layer. However, due to the shape of the terminal ester, the product is highly water-soluble, and when the layer is not separated, concentrated sulfuric acid is added to the reaction mixture to reduce the water-solubility of the product, thereby separating the target product Obtainable.

  The reactor is most preferably a container made of PFA (perfluoroethylene propene copolymer), and a container made of high-density polyethylene can be used, but glass and metal cannot be used due to corrosion problems.

  For purification, distillation is a common technique, but when the boiling point is high, it can be purified by column chromatography or the like.

  Next, the present invention will be described with reference to examples.

Example 1
(1) To a reactor made of PFA having an internal volume of 2000 ml equipped with a stirring blade, a thermometer and a nitrogen seal, 1000 g of 2-fluoro-2-methoxy-3,3-bis (trifluoromethyl) oxirane (purity 92 GC%) ( 4.03 mol) was added, and 1000 g (7.64 mol) of 75 wt% sulfuric acid was slowly added dropwise at room temperature. After completion of dropping, the mixture was stirred for 24 hours at an internal temperature of 40 ° C., and the upper layer was recovered. The recovered material was washed successively with saturated saline, 10 wt% K ₂ CO ₃ aqueous solution and concentrated sulfuric acid, and 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropanoic acid was washed from the washed organic layer. 932 g of methyl were obtained. The purity was 87 GC% and the yield was 89%.

(2) The above-mentioned (1) 928 g of crude 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropanoate with a purity of 87 GC% obtained in (1) was added. When a fraction having a boiling point of 107 to 108 ° C. was collected, 488 g of methyl 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropanoate having a purity of 99.2 GC% was obtained. The distillation yield was 60%. The NMR data is shown below.
[NMR data]
H-NMR (acetone-d6, TMS):
δ; 4.01 (CH ₃ )
δ; 7.45 (OH)
F-NMR (acetone-d6, CFCl ₃ ):
-73.78ppm (CF ₃ )

Example 2
To a reactor made of PFA with a capacity of 2000 ml equipped with a stirring blade, thermometer and nitrogen seal, 1000 g (4.03 mol) of 2-fluoro-2-methoxy-3,3-bis (trifluoromethyl) oxirane (purity 92 GC%) Then, 1000 g (10 mol) of 20 wt% hydrofluoric acid was slowly added dropwise at room temperature. After completion of the dropwise addition, the mixture was stirred at room temperature for 24 hours, but the layer separation was insufficient. Therefore, the reaction mixture was added to 1000 g of 95% by weight sulfuric acid and stirred for 3 hours, and the organic layer was recovered. The collected organic layer is washed successively with saturated saline, 10% K ₂ CO ₃ aqueous solution and concentrated sulfuric acid, and 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropane is washed from the washed organic layer. 1009 g of methyl acid was obtained. The purity was 83 GC%, and the yield was 92%.

Claims (3)

General formula

(Wherein R is a phenyl group, a benzyl group or an alkyl group having 1 to 12 carbon atoms) 2-fluoro-2-alkoxy-3,3-bis (trifluoromethyl) oxirane represented by acidic conditions 3,3,3-trifluoro-2-formaldehyde represented by the general formula (CF ₃ ) ₂ C (OH) COOR (wherein R is the same as defined above), Process for producing hydroxy-2-trifluoromethylpropanoic acid ester.   The 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropanoic acid ester according to claim 1, wherein the hydrolysis under acidic conditions is carried out in the presence of a hydrofluoric acid aqueous solution, a hydrochloric acid aqueous solution or a sulfuric acid aqueous solution. Manufacturing method.   The method for producing 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropanoic acid ester according to claim 1, wherein the purification is further performed by distillation or column chromatography.