JP2755530B2 - Method for producing fluorinated alcohol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing pentafluoropropanol in a short time.

[0002]

2. Description of the Related Art Pentafluoropropanol is a compound useful as a raw material for synthesizing various organic compounds. For example, pentafluoropropanol can be produced by reacting pentafluoropropanol with an alkali metal to form an alkoxide and then reacting with tetrafluoroethylene. Pentafluoropropyl vinyl ether is useful as a raw material for synthesizing various polymers because of its excellent copolymerizability.

[0003] Pentafluoropropanol is, for example,
It is known that it is produced by a method of reacting tetrafluoroethylene, hydrofluoric acid and formaldehyde in the presence of sulfuric acid (US Pat. No. 2,992,276).

[0004]

However, according to the above method, there is a problem that the reaction takes too much time.

[0005]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of intensive studies for the purpose of shortening the reaction time, it was found that the above object can be achieved by performing the above reaction in the presence of a specific Lewis acid, and to propose the present invention. Reached.

That is, the present invention is a process for producing pentafluoropropanol, which comprises reacting tetrafluoroethylene, hydrogen fluoride and formaldehyde in the presence of a Lewis acid comprising a metal fluoride.

[0007] The reaction pressure of tetrafluoroethylene in the present invention is not particularly limited. However, when the reaction pressure is too high, there is a disadvantage that the apparatus becomes considerably expensive.
Therefore, the pressure of tetrafluoroethylene is 1-30k
g / cm ² is practical, particularly preferably 5-20 k
g / cm ² . Also, tetrafluoroethylene is
It is also possible to adopt a method in which the reaction solution is sealed in a reactor before the reaction and is not supplied during the reaction, or it can be supplied continuously or intermittently during the reaction.

[0008] Hydrogen fluoride may be introduced into the reactor as a gas, or may be introduced as hydrofluoric anhydride previously liquefied. Furthermore, although the use of hydrofluoric acid containing water does not hinder the practice of the present invention, the former two are preferred from the viewpoint of reactor corrosion.

[0009] Formaldehyde is generally supplied to a reactor by supplying gaseous formaldehyde produced by thermally decomposing a formaldehyde precursor to the reactor, and by reacting the formaldehyde precursor in the reaction system in advance. A method of generating formaldehyde in the reaction system can be suitably employed below, and the latter method is particularly preferable from the viewpoint of reaction operation. Examples of the formaldehyde precursor include paraformaldehyde and trioxane.

The reaction ratio of these tetrafluoroethylene, hydrogen fluoride and formaldehyde is not particularly limited, but generally, hydrogen fluoride may be used in the range of 2 to 20 mol per mol of formaldehyde. By supplying tetrafluoroethylene into the reactor at the above-described pressure, the reaction proceeds spontaneously in the reaction solution.

In the present invention, the above reaction is carried out in the presence of a Lewis acid composed of a metal fluoride. As the Lewis acid composed of a metal fluoride, a known compound can be employed without any limitation. For example, a metal fluoride of Group 3B of the periodic table such as aluminum fluoride, gallium fluoride, and indium fluoride; a metal fluoride of Group 4B of the periodic table such as silicon fluoride, germanium fluoride, and tin fluoride; Periodic table 5B of arsenic fluoride, antimony fluoride, etc.
Group 8 metal fluorides of the periodic table such as iron fluoride, cobalt fluoride and nickel fluoride; Group 2B metal fluorides such as zinc fluoride and cadmium fluoride; Group 3A metal fluoride such as yttrium fluoride and lanthanum fluoride; Group 4A metal fluoride such as titanium fluoride and zirconium fluoride; Period such as vanadium fluoride and niobium fluoride Group 5A metal fluorides and the like can be given. Among these Lewis acids, in the present invention, in the Periodic Table, Group 3B, Group 4B, Group 5B, Group 8, Group 2B, Group 4A
Group metal fluorides can be suitably used, particularly since the reaction rate can be increased.

Although the amount of the Lewis acid used is not particularly limited,
In general, 0.01 mol per 1 mol of formaldehyde
It is preferable to select from the range of 0.5 to 0.5 mol, more preferably 0.02 to 0.2 mol.

This reaction is usually preferably carried out without solvent. The reaction temperature in this reaction is not particularly limited and may be selected according to the reaction rate.
It is preferable that the temperature be in the range of 120 ° C, particularly 30 to 90 ° C.

In the reaction of the present invention, when a relatively high pressure is applied to tetrafluoroethylene, the polymerization reaction may occur. In such a case, a polymerization inhibitor is added to the reaction system to prevent polymerization. Is preferably added. The polymerization inhibitor may be added to the reactor prior to the reaction, or may be contained in the introduced tetrafluoroethylene. As the polymerization inhibitor, any compound can be employed without any limitation as long as it is a compound for preventing the polymerization of tetrafluoroethylene. Illustrative polymerization inhibitors preferably used in the present invention, limonene, pinene, cymene,
Terpinene and the like can be mentioned.

[0015]

According to the method of the present invention, the reaction rate can be remarkably improved by reacting tetrafluoroethylene, hydrogen fluoride and formaldehyde in the presence of a specific Lewis acid. Fluoropropanol can be produced in a short time.

[0016]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to these examples.

Example 1 Trioxane 1 was placed in a stainless steel reactor having a capacity of 300 mL.
2 g, 5.4 g of TiF ₄ and 1 mL of limonene were charged, and the system was replaced with nitrogen. The reactor was cooled in a dry ice / methanol bath, and 40 g of hydrofluoric anhydride was introduced. Next, after introducing tetrafluoroethylene into the reactor, 60
C., and tetrafluoroethylene was supplied at a pressure of 20 kg / cm ² until the absorption of tetrafluoroethylene ceased. After 4 hours, the absorption of tetrafluoroethylene had ceased. After cooling and depressurizing, the reaction mixture was poured into ice water. After neutralizing this with ammonia gas, simple distillation, the distillate was dried with MgSO ₄ ,
29 g of pentafluoropropanol were obtained. At this time, 2.6 g of tetrafluorooxetane was obtained.

Comparative Example 1 A reaction was conducted in the same manner as in Example 1 except that TiF ₄ was not used, and it took 9 hours to absorb tetrafluoroethylene. Purification yielded 30.4 g of pentafluoropropanol and 8.2 g of tetrafluorooxetane.

Comparative Example 2 A reaction was carried out in the same manner as in Example 1 except that 39.2 g of sulfuric acid was used instead of TiF ₄ , and it took 7 hours to absorb tetrafluoroethylene. Purification yielded 18.9 g of pentafluoropropanol and 2.2 g of tetrafluorooxetane.

Example 2 The same reaction as in Example 1 was carried out except that various metal fluorides shown in Table 1 were used instead of TiF ₄ . Table 1 shows the types of metal fluorides, the absorption time of tetrafluoroethylene, and the yields of pentafluoropropanol and tetrafluorooxetane.

[0021]

[Table 1]

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI B01J 27/135 B01J 27/135 X 27/138 27/138 X C07B 61/00 300 C07B 61/00 300 (58) (Int.Cl. ⁶ , DB name) C07C 31/38 C07C 29/14 C07C 29/64 B01J 27/12 B01J 27/128 B01J 27/135 B01J 27/138

Claims (1)

(57) [Claims] 1. A process for producing pentafluoropropanol, comprising reacting tetrafluoroethylene, hydrogen fluoride and formaldehyde in the presence of a Lewis acid comprising a metal fluoride.