JPS649299B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 2,2,2-trifluoroethanol, and more specifically, the present invention relates to a method for producing 2,2,2-trifluoroethanol, and more specifically, the present invention relates to a method for producing 2,2,2-trifluoroethanol. The present invention relates to a method for producing 2,2,2-trifluoroethanol by reacting it with a hydroxyl carboxylate. 2,2,2-trifluoroethanol is a thermally extremely stable fluorine-containing alcohol with a weakly acidic OH group. Therefore, it is used to modify inorganic polymer phosphazene polymers that have heat resistance, flexibility at low temperatures, flame retardancy, and oil resistance. In addition, research has progressed in recent years to save energy, and waste heat in the medium and low temperature range (200 to 500°C) discharged from various production facilities can be used as a working medium for waste heat recovery power generation systems of large diesel engines.
2,2-trifluoroethanol is used. Traditionally, this alcohol has been produced by _LiAlH4 reduction of trifluoroacetic ester (J.Am.
Chem.Soc1968 (1948) and a method of deriving from 1,1,1-trifluoro-2-chloroethane are known. However, since LiAlH ₄ is expensive,
Industrially, the reduction method of trifluoroacetic acid ester is not practical. Known methods for deriving from 1,1,1-trifluoro-2-chloroethane include a method of melting and reacting with sodium acetate, and a method of reacting with sodium acetate using acetic acid as a solvent. However, the yield of these reactions depends on the reaction temperature, and in order to improve the yield, it is unavoidable that the reaction takes an extremely long time. Moreover, the obtained products are 2,
Since it is 2,2-trifluoroethyl acetate, there is the hassle of having to undergo another hydrolysis step. U.S. Patent No. 2,868,846 describes a solvent having a hydroxyl group,
For example, using ethylene glycol as a solvent, 1,
A method is described for reacting 1,1-trifluoro-2-chloroethane with an alkali metal salt to obtain the desired product. However, this reaction has a high reaction temperature, resulting in thermal deterioration of the glycols used as the solvent,
It is difficult to say that this method is satisfactory as an industrial manufacturing method, as corrosion of the reaction vessel material occurs and side reactions occur as the product is produced. The present inventors 2,
As a result of extensive research into methods for producing 2,2-trifluoroethanol, the general formula
1,1, represented by CF ₃ CH ₂ X (X is Cl or Br)
γ- 1-trifluoro-2-halogenated ethane
With butyrolactone as the solvent, the general formula RCOOM
(R is a hydroxylalkyl group having 5 or less carbon atoms,
By reacting with one or a mixture of two or more hydroxycarboxylic acid salts (M is Na or K), 2,
We have discovered that 2,2-trifluoroethanol can be synthesized, leading to the present invention. The details of the present invention will be explained below. The 1,1,1-trifluoro-2-halogenated ethane used in the reaction of the present invention is CF ₃ CH ₂ Cl and CF ₃ CH ₂ Br as shown in the above general formula. Furthermore, the hydroxycarboxylate salt represented by the general formula used in the present invention can easily form a lactone upon dehydration; one example is HO.
(CH ₂ ) ₃ COONa (sodium γ-hydroxybutyrate)
HO(CH ₂ ) ₃ COOK (gamma-hydroxybutyric acid potassium) and the like can be used, but are not limited to these. In addition, these hydroxyl carboxylates illustrated include, for example, γ-butyrolactone and NaOH,
The salt produced by reaction with KOH etc. may be directly subjected to the reaction. γ-butyrolactone used as a solvent and 1,
The molar ratio of 1,1-trifluoro-2-halogenated ethane (γ-butyrolactone/1,1,1-trifluoro-2-halogenated ethane) is 0.5 or more and 20 or less (preferably 0.8 or more and 15 or less). It is. If this molar ratio is smaller than 0.5, the solvent effect of γ-butyrolactone is not sufficient, and if it is larger than 20, the amount of γ-butyrolactone recovered increases significantly, making it uneconomical. Also, hydroxyl carboxylate/1,1,1-
The molar ratio of trifluoro-2-halogenated ethane is 0.25 or more and 10 or less (preferably 0.5 or more and 5 or less)
It is. The reaction temperature is 130℃ or higher and 250℃ or lower (preferably
(140℃ or higher and 230℃ or lower). If the reaction temperature is lower than 130°C, there will be disadvantages such as having to carry out the reaction for an extremely long time. Conversely, if the reaction temperature is higher than 250℃, γ-
This causes disadvantages such as thermal decomposition of butyrolactone and an increase in side reactions. The reaction pressure may be the pressure (self-pressure) generated by the raw material and product material, but the pressure at room temperature before the start of the reaction must be 40 Kg/cm ² G or less by using an inert gas such as nitrogen that does not adversely affect the reaction. The pressure may be increased so that The reason why the reaction according to the present invention produces 2,2,2-trifluoroethanol in one step without adding water is shown by the following formula, taking potassium γ-hydroxybutyrate as an example. It is thought that a reaction takes place. EXAMPLES In order to facilitate understanding of the present invention, Examples are shown below, but the scope of the present invention is not limited to these Examples. Example 1 Predetermined amounts of γ-butyrolactone and potassium γ-hydroxybutyrate were placed in a 200 ml autoclave (material: SUS304) equipped with a magnetic stirrer, and the autoclave was sealed. The system was evacuated and sampled in a pressure-resistant glass container in advance.
CF ₃ CH ₂ Cl was introduced into the autoclave through a conduit. After that, the inside of the autoclave was flushed with nitrogen for 4 hours.
The mixture was pressurized to Kg/cm ² G, heated to 200°C in an electric furnace, stirred, and reacted for 4 hours. After the reaction was completed, gas components coming out of the autoclave were collected in a trap cooled with dry ice methanol. Next, the lid of the autoclave was opened, and the contents were quickly passed through a glass filter to separate unreacted potassium γ-hydroxybutyrate and produced potassium chloride from the reaction solution. The collected potassium γ-hydroxybutyrate and potassium chloride were washed repeatedly with γ-butyrolactone and combined with the washing solution. The gas components and reaction solution recovered through these operations were quantified using a gas chromatograph using dioxane as an internal standard. The results are shown in Table 1. Example 2 In an autoclave, γ-butyrolactone and
Potassium γ-hydroxybutyrate was produced by reaction with KOH and subjected to the reaction. That is, a predetermined amount of γ-butyrolactone and solid caustic potassium (moisture 13 wt%) were placed in an autoclave,
The reaction mixture was heated to 180°C and stirred for 1 hour, followed by dehydration and distillation under vacuum. The distillate was analyzed by gas chromatography to quantify the distilled γ-butyrolactone.
After cooling the autoclave to room temperature, it was collected. Potassium γ-hydroxybutyrate in the liquid in the autoclave was determined by HLC analysis. Next, in the same manner as in Example 1, CF ₃ CH ₂ Cl was introduced into the autoclave, reacted, and analyzed. However, in this case, pressurization with nitrogen was not performed after introducing CF ₃ CH ₂ Cl. The results are shown in Table 1. Example 3 Using CF ₃ CH ₂ Br as a raw material, reaction temperature 150°C
The procedure was the same as in Example 1 except that. The results are shown in Table 1. 【table】

Claims (1)

[Claims] 1 1,1,1-trifluoro- ₂ -halogenated ethane represented by the general formula CF ₃ CH 2 A method for producing 2,2,2-trifluoroethanol, which comprises reacting with one or a mixture of two or more salts of a hydroxycarboxylic acid represented by a hydroxyalkyl group, M is Na or K.