JPH01249728A - Fluorination of organic compound - Google Patents

Abstract

PURPOSE:To produce the corresponding perfluoro-organic compound, by using a combination of fluorine gas and hydrogen fluoride as a fluorinating agent, in the continuous counter-current fluorinating of an organic compound with the fluorinating agent. CONSTITUTION:An organic compound of 6-25C, such as hydrocarbon, amine, ether, alcohol or carboxylic acid is continuously brought into contact with a fluorinating agent, a combination of fluorine gas and hydrogen fluoride, countercurrently at 70-150 deg.C under normal to 3 atmospheric pressure to give the corresponding perfluoro-organic compound. The molar ratio of the fluorine gas to the hydrogen fluoride is 1: (0.03-0.20). The amount of the fluorinating agent is 1-3 moles of fluorine gas, based on 1 mole of H atom. When a partially fluorinated compound is used so that H/F is 1/100-1/7 based on the starting substance, the corresponding perfluoro is obtained in a high yield.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for continuously fluorinating organic compounds.

(Prior Art) A method of fluorinating organic compounds with fluorine gas is well known. For example, JP-A-60-202122 describes a method of reacting polyether with fluorine. In such a fluorination reaction, a patch type and a continuous type are employed as in general chemical reactions.・The Tsuchi method has a relatively good yield of ・flat-fluoro organic compounds obtained by fluorination of organic compounds, but it has the disadvantage of low productivity. Therefore, from an industrial point of view, a continuous type is usually adopted in order to improve productivity. When fluorination is carried out in a continuous manner, in order to ensure good contact between the organic compound and the fluorine gas, a method is adopted in which the organic compound and the fluorine gas are supplied countercurrently to the reactor.

(Problems to be Solved by the Invention) However, in the continuous method as described above, it is difficult to completely fluorinate the organic compound as a raw material. That is, incompletely fluorinated compounds having hydrogen atoms bonded in their molecules are mixed in the product. The presence of incompletely fluorinated substances, even in trace amounts, is disadvantageous because it causes serious problems when used in various applications. On the other hand, if the reaction conditions are strict so that incompletely fluorinated compounds do not remain, 7Th,
After all, there was the problem of not being able to obtain the desired yield. Reduces the amount of organic compounds used as raw materials.
We have been conducting extensive research aimed at obtaining high yields of fluoroorganic compounds. As a result, the inventors discovered that the above object could be achieved by supplying hydrogen fluoride in addition to fluorine gas to the reactor as a fluorinating agent, thereby completing the present invention.

That is, the present invention provides a method for fluorinating an organic compound by continuously supplying an organic compound and a fluorinating agent to a reactor in countercurrent flow, in which fluorine gas and hydrogen fluoride are used together as the fluorinating agent. This is a method for fluorinating organic compounds.

As the organic compound used in the present invention, any organic compound having a hydrogen atom directly bonded to a carbon atom or having a carbon-carbon double bond can be used without any restriction. Generally, organic compounds that are liquid at the reaction temperature are preferred.

For example, hydrocarbons such as aliphatic hydrocarbons and aromatic hydrocarbons; amines such as linear or cyclic aliphatic primary amines, secondary or tertiary amines, and aromatic amines; linear or cyclic aliphatic Ethers such as group ethers, aromatic ethers, and polyethers; Alcohols such as linear or cyclic aliphatic alcohols and aromatic alcohols; Phenols; Aliphatic caldic acids, aromatic caldic acids, etc.; acid halides such as acid chlorides and acid fluorides, or calgenic acids and their derivatives such as acid anhydrides and esters; ketones; aldehydes; aliphatic sulfonic acids, aromatic sulfonic acids and acid chlorides derived therefrom; Examples include acid halides such as acid fluorides, sulfonic acids such as esters and derivatives thereof; sulfur-containing compounds such as thioethers, and the like. Also,
Those in which some of the hydrogen atoms are substituted with halogen atoms such as salt atoms may also be used. Among these, those having 4 to 50 carbon atoms, particularly 6 carbon atoms, are particularly preferred in the present invention.
It is an organic compound with ~25 pieces. In addition, when amines, or even trialkylamines, are used as raw materials, the desired y/o-fluoro organic compound can be obtained in high yield. The nine amines listed above include tripropylamine,
Examples include tributylamine, tributylamine, trihexylamine, zontylbutylamine, butylpropylamine, and the like.

A partially fluorinated organic compound in which some of the hydrogen atoms of the organic compound described above are replaced with fluorine atoms, for example, the ratio of the number of hydrogen atoms to fluorine atoms (H/F) is 1/1 or less, preferably 1
When a partially fluorinated organic compound with a molecular weight of 75 or less, more preferably 1/100 to 1/7, is used as a raw material, a 9-fluoro organic compound corresponding to the raw material can be obtained in high yield. This is a preferred embodiment of the present invention. However, the above-mentioned ratio of hydrogen atoms to fluorine atoms is an average value of all partially fluorinated organic compounds obtained by collecting a number of partially fluorinated organic compounds having various nucleation values.

In the present invention, fluorine gas and hydrogen fluoride are used together as the fluorinating agent. The ratio of fluorine gas and hydrogen fluoride is determined from o, oi to 1 mole of fluorine gas, considering the yield of the perfluoro organic compound obtained.
It is suitable to use 0.35 mol, preferably in the range of 0.03 to 0.20 mol. As hydrogen fluoride, commercially available anhydrous hydrofluoric acid can be used as it is or after further dehydration. Further, hydrogen fluoride generated by the reaction between the above-mentioned organic compound and fluorine gas can be recovered and reused.

The ratio of the organic compound to the fluorinating agent is not particularly limited (although there are no particular restrictions), the fluorinating agent may be in excess of the theoretical amount required to replace all hydrogen atoms in the organic compound with fluorine atoms. Generally, 1 to 6 mol, preferably 1 to 6 mol, per 1 mol of hydrogen atoms contained in the organic compound.
The fluorinating agent is used to give 3 moles of fluorine gas to 1 part.

The organic compound and the fluorinating agent are fed continuously in countercurrent into the reactor. As a result, the more fluorinated the organic compound that is the raw material, making it difficult for the fluorination reaction to proceed, the more it will come into contact with fluorine gas in a zone with a high fluorine gas content near the supply side of the fluorinating agent, and the reaction will occur. efficiency increases. The reactor used in the present invention is preferably a long cylindrical body in order to maintain a long contact time between the organic compound and the fluorinating agent. Preferably, the organic compound is supplied from one end of the long cylindrical body, and the fluorinating agent is supplied from the other end. Fluorine gas and hydrogen fluoride, which are fluorinating agents, may be supplied to the reactor after being mixed in advance, or may be supplied separately to the reactor. The fluorinating agent can be supplied as is, or it can be diluted to about 5% by volume with an inert gas such as nitrogen, helium, neon, carbon dioxide, etc. When using as a raw material a partially fluorinated organic compound having the above-mentioned R4 ratio of 115 or less, more preferably 1/100 to 1/7,
Good results are obtained using high concentrations of the fluorinating agent, greater than 20 volume factors, preferably greater than 50 volume factors.

On the other hand, the organic compound can be supplied as it is, but in order to perform the fluorination reaction mildly, it is necessary to dilute it with a perfluoro organic compound, especially a g-fluoro organic compound corresponding to the raw material organic compound. is preferred. The mixing amount of the organic compound and the perfluoro organic compound is not particularly limited, but the perfluoro organic compound may be mixed in an amount of 30 to 600 parts by weight, more preferably 60 parts by weight per 100 parts by weight of the organic compound.
It is preferable to use it in a range of 400 parts by weight.

The method of the present invention is effective when the above-mentioned organic compound and fluorinating agent are reacted in a continuous manner. Examples of the case where the organic compound and the fluorinating agent are reacted in a continuous manner include the following three cases.

■ When both the organic compound and the fluorinating agent are fed continuously to the reactor ■ When either the organic compound or the fluorinating agent is fed continuously to the reactor, and the other is fed intermittently ■ When both an organic compound and a fluorinating agent are intermittently supplied to the reactor In the present invention, nickel, nickel alloy, or other metals are used to increase the efficiency of contact between the organic compound and the fluorinating agent. It is preferable to use particles, Raschig rings, wire mesh, etc. as fillers.

The reaction is usually carried out under a pressure of normal pressure to 3 atm, but may be further pressurized. The reaction temperature is preferably selected from the range of 30 to 180°C, more preferably 70 to 150°C, taking into consideration the rate of the fluorination reaction and the yield of the desired g-fluoro compound. The residence time of the raw organic compound in the reactor is also not particularly limited, but is usually selected from the range of 1 to 80 hours. Nickel, nickel alloy, etc. are usually used as the material for the reactor.

Incidentally, a known catalyst such as brass, cobalt, copper, gold, and silver can also be used in the form of a net or particulate form.Also, the fluorination reaction can be carried out by irradiating light with a wavelength of 200 to 600 nm. It can also be promoted.

After the fluorination reaction, nitrogen purge, neutralization reaction, distillation, etc. are performed as necessary to remove hydrogen fluoride contained in the product and to increase the purity of the target safe fluoro organic compound.

The non-fluoro organic compound corresponding to the raw material targeted in the present invention includes those in which the hydrogen atoms of the raw material, non-fluorinated organic compound or partially fluorinated organic compound, are simply completely replaced with fluorine atoms. Of course, when raw materials having functional groups as mentioned above are used, it also includes compounds whose functional groups are removed or converted to other functional groups by fluorination, and furthermore, they may be used as raw materials. When a compound containing a carbon-carbon multiple bond is used, it also includes a compound in which fluorine atoms are added until the multiple bond is saturated.

When the number of carbon atoms in the raw material is 6 or more, depending on the case, the structure may change from chain to cyclic with the same number of carbons at the same time as fluorination, but the resulting fluoroorganic compound is also a perfluoroorganic compound as used in the present invention.

(Effects) According to the method of the present invention, the amount of incompletely fluorinated compounds having hydrogen atoms bonded to their molecules can be extremely reduced, and the target non- and monofluoro organic compounds can be produced in high yields. You can get it at a high rate.

Further, this effect is particularly remarkable when a partially fluorinated organic compound is used as the raw material organic compound. Therefore, the fluorinated product obtained by the method of the present invention can be used as it is even in applications where the contamination of incompletely fluorinated substances containing hydrogen atoms is avoided.

Although the details of the reason why the above-mentioned effects of the present invention are obtained are unknown, the present inventors assume that hydrogen fluoride promotes fluorination by fluorine gas.

Example 1 Electrolytic fluorination of triacylamine is carried out in anhydrous hydrofluoric acid, and fluorine containing fluorotrimethylamine is separated from the reaction solution and sediments, accumulating at the bottom of the electrolytic cell. The reaction product was extracted from the lower part of the electrolytic cell and used as a raw material for the fluorination reaction of the present invention. The composition (weight %) of this was as follows.・Ya-fluorotritythylamine 32.27%, other perfluorinated compounds 18.8%, partially fluorinated compounds 49% ()L/
F' (ratio of numbers) = 0.075). The analysis was performed using gas chromatography (GC-8A manufactured by Shimadzu Corporation; the column was a capillary column FS-WCOT with a length of 25 m and a diameter of 0.25 mm coated with silicone 0V-215 manufactured by Gascro Industries ■). .Column temperature is 65℃
And so. ), by gas chromatography-mass spectrometry. The value of (/F for the partially fluorinated compound) can be determined by calculating the area ratio for each peak of the partially fluorinated compound in the gas chromatogram and determining the compositional formula of the compound, and from this, Kt for the entire partially fluorinated compound. It was determined by calculating the ratio of the number of hydrogen atoms to fluorine atoms.

Using the above fluorinated product as a raw material, fluorination with fluorine gas was carried out to create a tube with an inner diameter of 1 cIIL and a length of 300 crIL filled with nickel shavings with a reflux condenser on the top.
The experiment was carried out using a nickel reactor.

The raw material was fed from the top of the reactor at a rate of 89/hour, and the fluorine gas was fed from the bottom of the reactor at a rate of 6/minute at room temperature. At the same time, hydrogen fluoride was added at a molar ratio of 10% to the fluorine gas to the fluorine gas supply line immediately before the reactor. In addition, the nitrogen gas was introduced into the center of the reactor for 24 hours.
-Feed at a rate of 7 minutes. External heating was applied to bring the temperature of the reactor to 140°C. The residence time of the reaction solution in the reactor was about 30 hours. After the reaction reached steady state, the reaction product was collected for 35 hours.

The amount of raw materials supplied to the reactor during this period was 2809
(Perfluorotritylamine 90,19, other non-fluoro compounds 52,79, partially fluorinated products 1
It was 37.2ri. The amount of reaction product is 260.79 (
The recovery rate was 934), and no incompletely fluorinated products were included. After washing this with water, by precision distillation /'P-
214.59 of fluorotripentylamine was obtained.

By treatment with fluorine gas, it becomes the mother fluorotribenzene.

Comparative Example 1 Using the nine electrolytic fluorination products shown in Example 1, fluorination of the product with fluorine gas and collection of the reaction product after the reaction reached a steady state were performed using hydrogen fluoride in fluorine gas. The procedure was carried out in exactly the same manner as in Example 1, except that the supply to the sample was stopped.

In this case, the amount of reaction product collected was 236.5.9 (recovery rate 84.5%), which was washed with water and precision distilled, resulting in 146.8 g of 9-fluorotritylamine.
I got it. The increase rate of tritylamine due to fluorine gas treatment is 63%.

Example 2 The amount of hydrogen fluoride added to the fluorine gas was varied. Except for dead bodies, the electrolytic fluorination product of tripentylamine was fluorinated in exactly the same manner as in Example 1, and the reaction product was (35 hours).

Table 1 shows the relationship between the amount of hydrogen fluoride added and the amount of fluorotribentylamine obtained by post-treatment (washing with water, distillation) of the collected reaction product. Electrolytic fluorination in anhydrous hydrofluoric acid yielded a fluorinated product containing monofluorotetrahydrobyran. The composition (weight %) was as follows.・Fluorotetrahydropyran 38%
, other /g-fluoro compounds 23%, partially fluorinated compounds 39%, ()I/F' (number ratio) = 0.13).

Using the above mixture as a raw material, fluorination with fluorine gas was performed using the same equipment as in Example 1. Raw materials were supplied from the top of the reactor at a rate of 109/hour, and fluorine gas was supplied from the bottom of the reactor at a rate of 10/hour at room temperature. The experiment was conducted three times, and 1.2% molar ratio of fluorine gas was added to the fluorine gas supply line just before the reactor.
, 8%.

33% hydrogen fluoride was added. Also, nitrogen gas was fed into the center of the reactor at a rate of 30 x rl 7 minutes.

The reactor was heated to a temperature of 140° C. from the outside. The residence time of the reaction solution in the reactor was about 25 hours. After the reaction reached steady state, the reaction product was
Time was taken. The amount of raw material mixture supplied to the reactor during this period was 300! i+(・ya-fluorotetrahydropyran 1149, other ・9-fluoro compounds 69
9, m fluoride 1179).

Table 2 shows the relationship between the amount of hydrogen fluoride added and the amount of g-fluorotetrahydropyran obtained.

In all cases, incompletely fluorinated substances were not included.

Claims (1)

[Claims] (1) In a method for fluorinating organic compounds by continuously supplying an organic compound and a fluorinating agent to a reactor in countercurrent flow, it is possible to use fluorine gas and hydrogen fluoride together as the fluorinating agent. Characteristic methods for fluorination of organic compounds.