JPS5838231A - Preparation of pentafluoropropionyl fluoride - Google Patents

Abstract

PURPOSE:To obtain the titled compound in a quantitative yield under mild reaction conditions industrially and advantageously in a short time, by bringing 1,2- epoxyhexafluoropropane in the vapor phase into contact with an alkali metallic fluoride supported on active carbon. CONSTITUTION:1,2-Epoxyhexafluoropropane in the vapor phase is brought into contact with an alkali metallic fluoride, e.g. KF or CsF, supported on active carbon, preferably in an inert gas, e.g. N2, at the boiling point of the formed CF3CF2COF (-28 deg.C/1atm)-200 deg.C, a pressure of 1-10atm and a space velocity of 50-1,000hr<-1> to give the aimed compound CF3CF2COF. The catalyst is prepared by dipping the active carbon in an aqueous solution of the alkali metallic fluoride, drying the active carbon, and heat-treating the active carbon in an inert gas, e.g. N2, at 300 deg.C higher than the reaction temperature (the boiling point of the CF3CF2COF-200 deg.C). USE:A synthetic intermediate for perfluoropropyl vinyl ether.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing pentafluoropropionyl fluoride.

Pentafluoropropionyl fluoride is useful, for example, as a synthetic intermediate for perfluoropropyl vinyl ether (see, for example, Example 1 of Japanese Patent Publication No. 38-1617). As a method for producing such pentafluoropropionyl fluoride, 1,2-
Methods of treating epoxy hexafluoropropane in the presence of various catalysts are known, but at least these methods use a solvent, high pressure, or require a long time for the reaction. It cannot be said that it is an advantageous method (
For example, see British Patent No. 1,019,788 M#)
. In particular, in a method in which 1,2-epoxyhexafluoropropane is treated in the presence of cesium fluoride without a solvent, 140
C. and 187 atm for 4 hours, and the yield of the target product was extremely low (see Example 25 of the same British patent specification).

An object of the present invention is to provide an industrially advantageous method for producing 1,2-epoxyhexafluoride, and the object is to support an alkali metal fluoride on activated carbon and apply it in a gas phase. This is achieved by contacting 1,2-epoxyhexafluoropropane with 1,2-epoxyhexafluoropropane.

According to the method of the present invention, unlike the prior art described above, pentafluoropropionyl fluoride, which is the target product, can be obtained in a short period of time and with an almost quantitative yield.

That is, in the method of the present invention, an alkali metal fluoride, which has been known as a rearrangement reaction catalyst for 1,2-epoxyhexafluoropropane, is supported on activated carbon, and 1,2-epoxyhexafluoropropane is added to the activated carbon in the gas phase. The present invention provides an industrially advantageous method for producing pentafluoropropionyl fluoride in quantitative yield by bringing propane into contact and reacting, allowing the reaction to proceed smoothly in a short time under mild reaction conditions.

The alkali metal fluoride supported on the activated carbon used in the present invention can be prepared by, for example, immersing the activated carbon in an aqueous solution of the alkali metal fluoride, drying the activated carbon, and then immersing the activated carbon in an inert gas such as a nitrogen stream at or above the reaction temperature described below. about 30
It can be prepared by heat treatment at a temperature 0°C higher. The content of alkali metal fluoride in the activated carbon is suitably 1 to 50% by weight based on the weight of the activated carbon. The type of alkali metal fluoride is not particularly limited, but cesium fluoride and potassium fluoride are preferred.

In the method of the present invention, the reaction temperature is usually the boiling point of pentafluoropropionyl fluoride (-28°C/
l atm) rl to 200°C, preferably room temperature to
The temperature is 150°C.

The reaction pressure is not particularly limited as long as it maintains the target product in a gaseous state, and can be freely selected from a wide range, whether it is increased pressure or reduced pressure.

Usually, a reaction pressure of 0.1 to 10 atmospheres is employed.

In addition, the space container is determined based on the content of alkali metal fluoride relative to the unit weight of activated carbon, the type of alkali metal fluoride, the type of activated carbon, reaction temperature, reaction pressure, and intended conversion rate 1j.
It will be determined as appropriate depending on the situation.

It is usually 50 to 1000 hr-1.

Furthermore, diluents such as nitrogen, helium, and argon can also be used in the production method of the present invention.

Next, Examples will be shown to further specifically explain the manufacturing method of the present invention.

Example 1 Activated carbon (Shirasagi CX, manufactured by Takeda Pharmaceutical Co., Ltd.) 3877 was immersed in a 30% by weight aqueous solution of potassium fluoride, and after separating the aqueous solution that was not impregnated, it was dried at 100 ° C. for 20 hours, and further dried in a nitrogen stream. , and heated at 350°C for 5 hours. Co-location of activated carbon supporting potassium fluoride is 42.6iii
The content of supported potassium fluoride was 9.1% by weight of the activated carbon.

A 1 m long 3/4 inch Hastelloy C reaction tube was filled with potassium fluoride-supported activated carbon 357, and heated in a nitrogen stream for 4 hours.
After heating at 00℃, the set temperature was set to 50℃, and 100m// of 1,2-epoxyhexafluoropropane was heated at atmospheric pressure.
for 3 hours at a flow rate of 1167 min (total 1167).

The effluent was transferred to a trap cooled with dry ice (101 g) and analyzed by gas chromatography, mass spectrometry and infrared spectroscopy. No raw material compound was detected, and all reaction products were pentafluoropropionyl fluoride (CF3CF2COF).

Example 2 Using the same catalyst and reactor as in Example 1, 56 mol% of 1,2-epoxyhexafluoropropane and 44 mol% of hexafluoropropene at a set temperature of 100°C.
A mixed gas of 200 m//min was flowed for 5 hours (total 5002). 470 grams of the waste was captured in a trap cooled with dry ice. As a result of the analysis, 1
, 2-epoxyhexafluoropropane was completely consumed and the reaction product was pentafluoroprohenyl fluoride. Obtained similar results.

Implementation f'j4 Using activated carbon supporting cesium fluoride (cesium fluoride contains 9.4% by weight of the activated carbon) and using the same reactor as in Example 1, 61 mol% of 1,2-epoxyhexafluoropropane was added. A mixed gas containing 39 mol% of fluoropropene was passed through the reactor at a flow rate of 100 rnl/min.

Infrared spectroscopic analysis of the product yielded pentafluoropropionyl fluoride containing an amount of 1,2-epoxyhexafluoroacetone.

Patent applicant: Daikin Industries, Ltd.

Claims (1)

[Claims] 1. 1°2- to the alkali metal fluoride supported on activated carbon
A method for producing pentafluoropropionyl fluoride, which comprises contacting epoxy hexafluoropropane in a gas phase. 2. The method according to claim 1, wherein the two contacts are carried out at a temperature between the boiling point of pentafluoropropionyl fluoride and 200°C. 3. The method according to claim 1 or 2, wherein the alkali metal trifluoride is potassium fluoride or cesium fluoride.