JP2018090492A - Fluorination method and production method of perfluoropolyether-based compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a perfluoropolyether-based compound with high efficiency from an inexpensive and readily available raw material compound such as a polyethylene glycol with a large number of repeating units.SOLUTION: A fluorination method includes: a step (1) to introduce a compound represented by formula (i): R-O-(R-O-)-R, a hydrogen fluoride scavenger, an inert gas, fluorine gas, and a solvent into a reactor; a step (2) to remove the hydrogen fluoride scavenger from the reactor; a step (3) to circulate the inert gas and fluorine gas through the reactor; and a step (4) to circulate a perhalogen unsaturated compound through the reactor while conducting the step (3). A production method of a perfluoropolyether-based compound including the fluorination method is also disclosed.SELECTED DRAWING: None

Description

  The present invention relates to a fluorination method for producing a perfluoropolyether compound useful as a lubricant and a method for producing a perfluoropolyether compound using the fluorination method.

A perfluorinated polyether compound is a compound widely used as a lubricant, and a perfluoropolyether compound having a terminal group of —CH ₂ OH is known to be particularly useful.

  As a method of fluorinating all C—H portions in hydrocarbon compounds to C—F, a method of fluorination using a fluorine gas, or generation of hydrogen fluoride by electrolysis in an electrolytic cell A method of fluorinating a product to be used as a fluorine atom source is known. As a reaction using fluorine gas, a gas phase method and a liquid phase method are known.

  However, the electrolytic fluorination reaction has a problem that an isomerization reaction, a C—C bond cleavage and a recombination reaction easily occur, and a target compound cannot be obtained with high purity. Moreover, when it reacts with fluorine gas in a gaseous phase, there was a problem that a C—C single bond was broken and many types of by-products were generated.

As a method for solving the problem of the gas phase method, a method of reacting with fluorine gas in a liquid phase has been reported (for example, Patent Document 1). However, the method of Patent Document 1 has the following problems.
・ Not suitable for fluorination of high molecular weight polyethylene glycol (n ≧ 4).
When NaF is present in the reactor, since the perfluorination is carried out in the presence of NaF, the terminal decomposition proceeds and the target product cannot be obtained.
・ When NaF is installed outside the reactor and the gaseous product is circulated, HF generated during the introduction of polyethylene glycol decomposes the ether bond, which is not suitable for fluorination of polyethylene glycol with a large number of repetitions. In order to prevent the decomposition of the ether bond, the introduction rate must be extremely reduced.
-Although low molecular weight hydrocarbons are added for perfluorination, in the case of hydrocarbons, there is a high probability that HF will be by-produced and side reactions will proceed.

Japanese Patent No. 2945693

  The present invention is made for the purpose of solving the problems of conventional methods, and provides a method capable of producing perfluoropolyether compounds with high efficiency from inexpensive and readily available raw material compounds such as polyethylene glycol having a large number of repetitions. The purpose is to do.

The present inventor has intensively studied to solve the above problems. As a result, the raw material can be introduced quickly by allowing the hydrogen fluoride scavenger to coexist in the reaction system when the raw material is introduced, and F ₂ by sequentially introducing the fluorine gas for the reaction consumption in the first stage fluorination step. After reducing the loss and then separating the hydrogen fluoride scavenger, the perfluorinated polyether compound is produced in high yield by circulating the perhalogen unsaturated compound while performing the second stage fluorination step. As a result, the present invention has been completed. That is, the present invention includes the following aspects.

[1] A step (1) of introducing a compound represented by the following formula (i), a hydrogen fluoride scavenger, an inert gas, a fluorine gas, and a solvent into a reactor;
After step (1), removing hydrogen fluoride scavenger from the reactor (2);
A step (3) of passing an inert gas and a fluorine gas through the reactor after the step (2);
A method for fluorinating a compound represented by the following formula (i), comprising a step (4) of circulating a perhalogen unsaturated compound in the reactor while performing the step (3).
R ¹ —O— (R—O—) _n —R ² (i)
In formula (i), (R—O—) represents a linear or branched repeating unit having 2 to 3 carbon atoms, R ¹ and R ² represent a hydroxyl-protecting group, and n represents 4 to 20 Represents an integer.

[2] The fluorination method according to item [1], wherein R ¹ and R ² are acyl groups.
[3] The fluorination method according to item [1] or [2], wherein the hydrogen fluoride scavenger is an alkali metal fluoride.

[4] The fluorination method according to any one of items [1] to [3], wherein the solvent in the step (1) is a completely halogen-substituted compound.
[5] The fluorination method according to any one of items [1] to [4], and
The manufacturing method of the compound represented by following formula (ii) including the process (5) which introduce | transduces C1-C3 alcohol into the said reactor after the said process (4), and performs esterification reaction.
_{^{R 3 O-CO-CF 2}} -O- (Rf) n-2 -CF 2 -CO-OR 4 (ii)
In the formula (ii), R ³ and R ⁴ represent an alkyl group having 1 to 3 carbon atoms, and Rf is a perfluoropolyether chain in which all hydrogen atoms of R in the formula (i) are substituted with fluorine atoms. N represents an integer of 4 to 20.

[6] A method for producing a compound represented by the following formula (iii), comprising a step (6) of reducing the compound obtained by the production method according to item [5] with a metal borohydride.
HO—CH ₂ —CF ₂ —O— (R f) _n−2 —CF ₂ —CH ₂ —OH (iii)
In formula (iii), Rf and n have the same meanings as Rf and n in formula (ii).

  According to the present invention, when producing a perfluoropolyether compound from a cheap and easily available raw material compound such as polyethylene glycol having a large number of repetitions, it can be fluorinated while suppressing the decomposition reaction of the ether bond, A perfluoropolyether compound can be produced in a short time and with a high yield.

  Hereinafter, the fluorination method and the method for producing a perfluoropolyether compound according to the present invention will be described in detail. In the “perfluoropolyether compound” in the present invention, the polyether chain may be perfluorinated and the terminal portion may not be perfluorinated.

[Fluorination method]
The fluorination method of the present invention is a fluorination method of a compound represented by the following formula (i) (hereinafter also referred to as “compound (i)”), which comprises the compound (i), a hydrogen fluoride scavenger, A step (1) of introducing an inert gas, a fluorine gas, and a solvent into the reactor; a step (2) of removing a hydrogen fluoride scavenger from the reactor after the step (1); Step (3) for passing an inert gas and a fluorine gas through the reactor after 2), Step (4) for flowing a perhalogen unsaturated compound through the reactor while performing the step (3), It is characterized by including.
R ¹ —O— (R—O—) _n —R ² (i)
In formula (i), (R—O—) represents a linear or branched repeating unit having 2 to 3 carbon atoms, R ¹ and R ² represent a hydroxyl-protecting group, and n represents 4 to 20 Represents an integer.

<Step (1)>
Step (1) is a raw material introduction step of introducing raw materials such as the compound (i), hydrogen fluoride scavenger, inert gas, fluorine gas, and solvent into the reactor.

The compound (i) as -R-O-in, for _{example, -CH 2 -CH 2 -O -,} - CH 2 -CH 2 -CH 2 -O -, - CH 2 -CH (CH 3) -O _{-, - CH (CH 3)} -CH 2 -O- and the like.

Here, the terminal of the product obtained by fluorinating the compound (i) by the fluorination method of the present invention is derived from a structure derived from primary OH (next to oxygen is —CF ₂ —) and from secondary OH. There may be a case where both the structure (next to oxygen is —CF (CF ₃ ) —) exist (mixed). In this way, a product in which two kinds of terminal structures are mixed is subjected to an esterification step by introducing an alcohol, which will be described later, whereby a structure derived from primary OH generates an alkoxycarbonyl group as a terminal group by defluoride and esterification. On the other hand, the structure derived from secondary OH produces —CF ₂ —CO—CF ₃ as a terminal group by defluorination. Further, the alkoxycarbonyl group is converted to —CH ₂ OH through a reduction step. In addition, when —R—O— is —CH ₂ —CH ₂ —O— or —CH ₂ —CH ₂ —CH ₂ —O—, there is no mixture, and the following formula (ii) and formula (iii) Only the compound represented by is produced. When such a mixture is not used, a compound having alkoxycarbonyl groups at both ends can be obtained as a single component, which is preferable because purification becomes easy. On the other hand, when mixed, it may be obtained as a mixture of both-end alkoxycarbonyl, one-end alkoxycarbonyl-one-end ketone, and both-end ketone, and it may be necessary to isolate each.

In the compound (i), R ¹ and R ² may be the same or different. The hydroxyl protecting group for R ¹ and R ² is composed of a divalent linking group and a monovalent organic group. Examples of the divalent linking group include —CO—, —SO ₂ —, —O—, —CH ₂ —, —C ₂ H ₄ —, —SO ₂ NR′—, —CONR′— (R ′ represents Lower alkyl having 1 to 3 carbon atoms) and the like, and —CO— is preferable because it can be easily synthesized. Examples of monovalent organic groups include alkyl groups, cycloalkyl groups, vinyl groups, allyl groups, phenyl groups, benzyl groups, amino groups, nitrile groups, halogenated alkyl groups, halogenated cycloalkyl groups, and halogenated vinyl groups. A halogenated allyl group, a halogenated phenyl group, a halogenated benzyl group, a halogenated amino group, and the like. From the viewpoint of availability, an alkyl group is preferable, and a methyl group is particularly preferable.

  Specific examples of the protecting group include formyl, acetyl, ethoxyacetyl, fluoroacetyl, difluoroacetyl, trifluoroacetyl, chloroacetyl, dichloroacetyl, trichloroacetyl, bromoacetyl, dibromoacetyl, tribromoacetyl, propionyl, and 2-chloro. Propionyl, 3-chloropropionyl, butyryl, 2-chlorobutyryl, 3-chlorobutyryl, 4-chlorobutyryl, 2-methylbutyryl, 2-ethylbutyryl, valeryl, 2-methylvaleryl, 4-methylvaleryl, hexanoyl, isobutyryl, isovaleryl, pivaloyl, benzoyl, o -Chlorobenzoyl, m-chlorobenzoyl, p-chlorobenzoyl, o-hydroxybenzoyl, m-hydroxybenzoyl, p-hydroxybenzoyl, -Acyl groups such as acetoxybenzoyl, o-methoxybenzoyl, m-methoxybenzoyl, p-methoxybenzoyl, p-nitrobenzoyl, silyl groups such as trimethylsilyl, triethylsilyl, t-butyldimethylsilyl, t-butyldiphenylsilyl, tetrahydro Alkoxymethyl groups such as pyranyl, methoxymethyl, methoxyethoxymethyl, 1-ethoxyethyl, benzyl group, p-methoxybenzyl group, t-butyl group, trityl group, methyl group, 2,2,2-trichloroethoxycarbonyl group And allyloxycarbonyl group. Of these, acyl groups are preferred.

In the compound (i), n is preferably an integer of 4 to 10, more preferably an integer of 5 to 8.
As the compound (i), a commercially available product may be used, or a compound obtained by reacting a polyether having a hydroxyl group with chloride or fluoride may be used.

  Examples of the hydrogen fluoride scavenger include alkali metal fluorides such as NaF and KF, and organic bases such as trialkylamine. Solid alkali metal fluorides are preferred for ease of separation, and NaF is particularly preferred. preferable. By allowing the hydrogen fluoride scavenger to coexist in the reaction system when the raw material is introduced, it is possible to suppress the decomposition reaction of the ether bond by hydrogen fluoride, so that the fluorination reaction can be performed in a high yield.

  As the solvent, a compound having high solubility of the compound (i) is preferable, a completely halogen-substituted compound not containing a C—H bond is more preferable, and a perhalogen alkane containing a fluorine atom and a chlorine atom is particularly preferable. . When a compound containing a C—H bond is used as a solvent, the C—H bond in the solvent reacts with the fluorine gas, and there is a concern that the decomposition reaction may be accelerated due to an increase in the amount of fluorine gas used and a temperature rise due to reaction heat. The

  The completely halogen-substituted compound is preferably a saturated one having 2 to 8 carbon atoms, and may be cyclic, linear or branched, and may contain an ether bond. For example, dichlorotetrafluoroethane , Trichlorotrifluoroethane, dichlorohexafluoropropane, tetrachlorohexafluorobutane, dichlorotrifluoroethyl trifluoromethyl ether, dichlorotrifluoroethyl pentafluoroethyl ether, n- or iso-heptafluoropropyl dichlorotrifluoroethyl ether, penta Examples include fluoroethyl heptafluoropropyl ether, perfluorocyclobutene, perfluoro (methylcyclopropene), perfluoropolyether oil, and the like.

The said solvent may be used individually by 1 type, or may be used in combination of 2 or more type.
It is desirable to introduce the solvent and the hydrogen fluoride scavenger into the reactor before introducing the compound (i). A method in which the solvent and the hydrogen fluoride scavenger are simultaneously introduced into the reactor and then the reactor is sealed is simple and preferable.

  As a method for introducing the compound (i), a method in which the compound (i) is dissolved and supplied in the solvent while an inert gas and a fluorine gas are circulated in the reactor is preferable. When the compound (i) is introduced into the reactor before introducing the fluorine gas, the decomposition of the by-produced hydrogen fluoride and the ether bond proceeds and the by-product volatilizes, so the yield tends to decrease. It is in.

  As a method for introducing the inert gas and the fluorine gas, a step of introducing the inert gas and the fluorine gas before introducing the compound (i) into the reactor or together with introducing the compound (i) into the reactor. Preferably, (1a) and a step (1b) of introducing fluorine gas or an inert gas and fluorine gas after introducing the compound (i) into the reactor are present.

≪Process (1a) ≫
In the step (1a), the inert gas and the fluorine gas are introduced into the reactor before the compound (i) is introduced into the reactor or together with the introduction of the compound (i) into the reactor.

  The concentration of fluorine gas to be circulated in the reactor is preferably 1 to 50% by volume, more preferably 10 to 30% by volume. If the fluorine gas concentration is too high, a flammable mixture is formed in the solvent and fluorine gas, increasing the possibility of an explosive reaction, while if the fluorine gas concentration is too low, the reaction rate decreases and the reaction time increases. Tend to be inefficient. The inert gas is circulated in the reactor so that the concentration of the fluorine gas becomes the same, but the inert gas and the fluorine gas may be introduced in different systems, and the mixed gas obtained by diluting the fluorine gas with the inert gas in advance is reacted. It may be introduced into the vessel. As the inert gas, nitrogen gas, helium gas, argon gas and the like are preferable because of easy availability and handling.

  In the step (1a), the temperature in the reactor when introducing the fluorine gas is preferably -20 to 60 ° C, more preferably -10 to 30 ° C. If the temperature is too low, the reaction rate decreases, while if the temperature is too high, the possibility of an explosion reaction increases. Moreover, the pressure in the reactor when introducing the fluorine gas is preferably 0.10 to 0.20 MPa, more preferably 0.10 to 0.15 MPa. If the pressure is too low, the reaction rate decreases, while if the pressure is too high, the possibility of an explosion reaction increases.

<< Step (1b) >>
The step (1b) is a step performed subsequent to the step (1a) and the step of introducing the compound (i) into the reactor, and introducing fluorine gas or an inert gas and fluorine gas into the reactor. A first fluorination step of fluorinating the compound (i). The introduction method of the fluorine gas in the step (1b) is preferably a distribution method or a batch method.

  In the distribution method, a fluorination reaction is performed by flowing a fluorine gas diluted with an inert gas into the reactor. The fluorine gas concentration is preferably 5 to 50% by volume, more preferably 10 to 30% by volume. If the fluorine gas concentration is too high, a flammable mixture is formed in the solvent and fluorine gas, increasing the possibility of an explosive reaction, while if the fluorine gas concentration is too low, the reaction rate decreases and the reaction time increases. Become inefficient. Further, when introducing the fluorine gas, the temperature in the reactor is preferably -20 to 60 ° C, more preferably -10 to 30 ° C, and the pressure in the reactor is preferably 0.10 to 0.20 MPa. More preferably, it is 0.10 to 0.15 MPa. If the temperature is too low, the reaction rate decreases, while if the temperature is too high, the possibility of an explosion reaction increases. If the pressure is too low, the reaction rate decreases, while if the pressure is too high, the possibility of an explosion reaction increases. The distribution time is preferably 1 to 3 hours.

  In the batch system, fluorine gas is introduced into a reactor substituted with an inert gas. The reactor outlet is closed, and the pressure-adjusted fluorine gas is introduced from the inlet by the amount consumed by the reaction. The pressure in the reactor at the time of introducing the fluorine gas is preferably 0.11 to 0.30 MPa, more preferably 0.15 to 0.25 MPa. If the pressure is too low, the reaction rate will decrease and the reaction time will be longer and inefficient, while if the pressure is too high, a flammable mixture will form in the solvent and fluorine gas, possibly causing an explosive reaction Becomes higher. Further, the temperature in the reactor when introducing the fluorine gas is preferably -20 to 60 ° C, more preferably -10 to 30 ° C. If the temperature is too low, the reaction rate decreases, while if the temperature is too high, the possibility of an explosion reaction increases. The fluorine gas concentration is determined according to the pressure.

  The degree of fluorination in the step (1b) is preferably 50 to 90%, more preferably 70 to 85%. The degree of fluorination as used herein refers to the ratio of hydrogen atoms in the compound (i) replaced with fluorine atoms. When the degree of fluorination is low, the decomposition reaction in the post-process becomes prominent and the yield decreases. On the other hand, when the degree of fluorination is high, the decomposition reaction of the hydroxyl protecting group proceeds and the yield tends to decrease. is there.

<Step (2)>
Step (2) is a separation step for removing the hydrogen fluoride scavenger from the reactor. When the hydrogen fluoride removing agent is not separated, in the step (4) to be described later, the decomposition reaction of the terminal of the compound (i) proceeds and the target product tends not to be obtained.

  The method for removing the hydrogen fluoride scavenger is preferable because separation by filtration is simple. Specifically, after purging the inside of the reactor with an inert gas, the reactor is opened and the reaction liquid in which the hydrogen fluoride scavenger is turbid is passed through the cellulose filter paper, thereby supplementing the reaction liquid and hydrogen fluoride. The agent can be separated. Since the working time can be shortened, there is a method of separating the reaction liquid and the hydrogen fluoride scavenger by installing a filter inert to the fluorine gas in the reactor and circulating the reaction liquid from the drain valve. More preferable. Examples of the filter inert to the fluorine gas include a filter made of a metal such as SUS or nickel or a Teflon material.

  The removal of the hydrogen fluoride scavenger is preferably performed in a dry atmosphere, and more preferably in an inert gas atmosphere. Since the hydroxyl-protecting group of compound (i) in which several hydrogen atoms are substituted with fluorine atoms easily reacts with water, side reaction proceeds when the reaction solution after step (1) is brought into contact with the atmosphere. As a result, the yield decreases.

<Step (3)>
Step (3) is a second fluorination step in which an inert gas and a fluorine gas are passed through the reactor to advance the fluorination reaction.

  In the step (3), the temperature in the reactor is preferably not less than the boiling point (20 ° C.) of HF, more preferably 20 ° C. to 100 ° C., further preferably 20 ° C. in order to efficiently remove by-produced HF. ~ 60 ° C. When the said temperature is too high, the possibility of an explosion reaction will become high and a yield will fall. Further, the pressure in the reactor is preferably 0.10 to 0.20 MPa, more preferably 0.10 to 0.15 MPa. If the pressure is too low, the reaction rate decreases, while if the pressure is too high, the possibility of an explosion reaction increases.

  The fluorine gas concentration is preferably 5 to 50% by volume, more preferably 10 to 30% by volume. If the fluorine gas concentration is too high, a flammable mixture is formed in the solvent and fluorine gas, increasing the possibility of an explosive reaction, while if the fluorine gas concentration is too low, the reaction rate decreases and the reaction time increases. Tend to be inefficient.

<Process (4)>
In the latter stage of the fluorination reaction, the reaction rate of the fluorination reaction decreases. Step (4) is a third fluorination step in which a perhalogen unsaturated compound is added to the reactor while performing the step (3) in order to advance the fluorination reaction efficiently. If the step (4) is not performed, hydrogen atoms remain in the compound and a perfluoro compound tends to be not obtained.

  Examples of the perhalogen unsaturated compound include hexafluorobenzene, hexachlorobenzene, chloropentafluorobenzene, trichlorotrifluorobenzene, decafluorobiphenyl, octafluoronaphthalene, heptafluoro-1-butadiene, decafluoro-1-pentadiene, and tetrachloroethylene. , Trichlorofluoroethylene, dichlorodifluoroethylene, trichlorotrifluoropropene, dichlorotetrafluoropropene, and the like, among which hexafluorobenzene, which is easy to obtain and handle, is particularly preferable. When a hydrocarbon compound such as benzene is used instead of a perhalogen unsaturated compound, fluorine gas is consumed for fluorination of the C—H bond in the hydrocarbon compound, so that the amount of fluorine gas used increases.

  As a method of adding the perhalogen unsaturated compound, it is preferable to introduce a constant amount by dissolving in a solvent. The flow rate of the perhalogenated unsaturated compound is preferably 1/50 to 1/5 mol times, more preferably 1/30 to 1/10 mol times the fluorine gas flow rate. If the flow rate is too small, the progress of the fluorination reaction is delayed and the reaction time becomes long. On the other hand, if the flow rate is too high, a flammable mixture is generated in the solvent and fluorine gas, and an explosion reaction is possible. Tend to be higher.

[Method for producing perfluoropolyether compound]
The method for producing the perfluoropolyether compound of the present invention includes the fluorination method of the present invention described above, and after the step (4), an alcohol having 1 to 3 carbon atoms is introduced into the reactor. And a method for producing a compound represented by the following formula (ii) (hereinafter also referred to as “compound (ii)”), which comprises the step (5) of conducting an esterification reaction, and obtained after the step (5). And a method for producing a compound represented by the following formula (iii) (hereinafter also referred to as “compound (iii)”), which comprises the step (6) of reducing the compound (ii) with a metal borohydride.
_{^{R 3 O-CO-CF 2}} -O- (Rf) n-2 -CF 2 -CO-OR 4 (ii)
HO—CH ₂ —CF ₂ —O— (R f) _n−2 —CF ₂ —CH ₂ —OH (iii)
In the formulas (ii) and (iii), R ³ and R ⁴ represent an alkyl group having 1 to 3 carbon atoms, and Rf represents perfluoro having all the hydrogen atoms of R in the formula (i) substituted with fluorine atoms. Represents a polyether chain, and n is an integer of 4 to 20.

<Step (5)>
Step (5) is an esterification step for introducing alcohol into the reactor. Since the compound produced in the step (4) easily reacts with moisture in the atmosphere to become a carboxylic acid compound, considering the ease of handling in the subsequent step, the compound (ii) It is preferable to do.

As said alcohol, methanol, ethanol, n-propanol etc. are mentioned, for example. Of these, methanol is preferred.
The reaction temperature for esterification is preferably 0 to 60 ° C, more preferably 10 to 40 ° C. The reaction pressure is preferably 0.1 to 0.2 MPa, more preferably 0.1 to 0.15 MPa. The amount of alcohol introduced is preferably 2 to 10 times the theoretical amount, more preferably 3 to 5 times.

  The compound (ii) can be isolated as a residue obtained by distilling off the solvent. In order to completely remove by-products such as hydrogen fluoride before distilling off the solvent, washing with alkaline water is preferred. Alkaline water is not particularly limited, but sodium hydrogen carbonate water is preferred from the standpoint of availability and handling. After washing with alkaline water, the solvent layer separated into two layers is recovered and the solvent is distilled off to isolate the compound (ii), and the recovered solvent can be easily reused and completely halogenated. Loss of expensive solvents such as compounds can be reduced.

<Step (6)>
Step (6) is a reduction reaction step in which the compound (iii) is obtained by mixing the compound (ii), an alcohol and a metal borohydride.

  The alcohol can be selected from alcohols having 1 to 5 carbon atoms, and ethanol is particularly preferable. The borohydride metal can be selected from an alkali metal salt of borohydride or an alkaline earth metal salt of borohydride, and sodium borohydride is particularly preferred because of its availability and handling.

<Example of reaction>
Compound (i) in steps (1) to (4) is a compound derived from polyethylene glycol, that is, —R—O— is —CH ₂ CH ₂ —O—, and R ¹ and R ² are both —COCH ₃ . A reaction example using a compound, using methanol as the alcohol in step (5), and using sodium borohydride and ethanol as the metal borohydride and alcohol in step (6) is shown below. In addition, this invention is not limited to the following reaction examples.

EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not limited to these Examples at all.
[Example 1]
<Raw material preparation process>
30 g of a polyethylene glycol (PEG) mixture having 7 and 8 repetitions was introduced into a 200 mL three-necked flask, and nitrogen gas was circulated at 100 mL / min while stirring with a stirrer chip. With nitrogen gas flowing at 100 mL / min, 81 g of acetyl chloride (CH ₃ COCl) was introduced into the three-necked flask in three portions, and stirring was continued for 15 hours. The collected reaction solution was dissolved in 800 mL of ethyl acetate and introduced into a separatory funnel. After 100 mL of saturated NaHCO ₃ water was introduced into the separatory funnel and stirred, the ethyl acetate phase was recovered. Ethyl acetate was distilled off with an evaporator to obtain 35 g of product (1-i). The obtained product (1-i) was analyzed by ¹ H-NMR and ¹³ C-NMR, and found to be CH ₃ CO—O— (C ₂ H ₄ O) _n —COCH ₃ (n = 7, 8). I confirmed that there was.

<Step (1a)>
Into a 1 L autoclave, 35 g of NaF and 400 mL of tetrachlorohexafluorobutane (HFTCB) were introduced and sealed. Stirring in the autoclave was started, and nitrogen gas was purged through the autoclave at 800 mL / min for 1 hour. While circulating nitrogen gas at 800 mL / min, the autoclave was immersed in a refrigerant cooled to −10 ° C., and the autoclave was cooled to about −10 ° C. Fluorine gas was circulated at 200 mL / min, and the inside of the autoclave was purged with 20 vol% fluorine gas. While flowing fluorine gas at 200 mL / min and nitrogen gas at 800 mL / min, 10.0 g of CH ₃ CO—O— (C ₂ H ₄ O) _n —COCH ₃ (n = 7,8) was dissolved in 200 mL of HFTCB. And introduced at a flow rate of 3.3 mL / min.

<Step (1b)>
Nitrogen gas was circulated through the autoclave at 800 mL / min for purging. The flow of nitrogen gas was stopped, the autoclave outlet was closed, and the inside of the autoclave was set to 0.1 MPaA in a nitrogen atmosphere. 0.2 MPaA of 100% by volume fluorine gas was introduced into the autoclave through a mass flow controller adjusted to a flow rate of 200 mL / min. An amount of fluorine gas in which 68% of the hydrogen atoms in CH ₃ CO—O— (C ₂ H ₄ O) _n —COCH ₃ were replaced with fluorine atoms was introduced into the autoclave while monitoring the integrated value of the mass flow controller.

<Step (2)>
The autoclave was purged by flowing nitrogen gas at 800 mL / min for 1 hour. The autoclave was opened in a nitrogen atmosphere glove box, and the reaction solution in which NaF was turbid was filtered to remove NaF from the reaction solution. The reaction solution from which NaF was removed was introduced into an autoclave and sealed.

<Steps (3) and (4)>
Stirring in the autoclave was started, and the autoclave was heated with an external heater so that the temperature inside the autoclave was about 30 ° C. Nitrogen gas was passed through the autoclave at 450 mL / min and fluorine gas at 50 mL / min to initiate the fluorination reaction. After circulating nitrogen gas and fluorine gas for 30 minutes, about 1.5 g of C ₆ F ₆ was dissolved in 30 mL of HFTCB while flowing nitrogen gas and fluorine gas and introduced at 0.5 mL / min. As a result of analyzing the obtained reaction product by ¹ H-NMR, it was confirmed that no hydrogen atoms remained in the compound.

<Step (5)>
After introducing C ₆ F ₆ into circulation, the circulation of fluorine gas was stopped, and nitrogen gas was circulated at 450 mL / min for 1 hour to purge the autoclave. The nitrogen gas flow was stopped, and 40 g of methanol was introduced under a nitrogen atmosphere of 0.1 MPaA in the autoclave. After stirring the autoclave for 30 minutes, the reaction solution was recovered. The recovered reaction solution was washed with saturated aqueous sodium hydrogen carbonate, the solvent layer separated into two layers was recovered, and the solvent was distilled off with an evaporator to obtain 16.7 g of the product (1-ii). As a result of analyzing the obtained product (1-ii) by ¹⁹ F NMR, CH ₃ O—CO—CF ₂ —O— (C ₂ F ₄ O) _n —CF ₂ —CO—OCH ₃ (n = 5) 6).

<Step (6)>
In a 25 mL eggplant flask, CH ₃ O—CO—CF ₂ —O— (C ₂ F ₄ O) _n —CF ₂ —CO—OCH ₃ (n = 5,6) 16 g, ethanol 150 g and sodium borohydride 1.1 g Was introduced and stirred. After 4 hours, 4 mL of 35% hydrogen chloride was added. The reaction solution was washed with water and extracted with tetrachlorohexafluorobutane. Tetrachlorohexachlorobutane was distilled off from the extract to obtain about 14 g of product (1-iii). As a result of analyzing the obtained product (1-iii) by ¹ H NMR and ¹⁹ F NMR, HO—CH ₂ —CF ₂ —O— (C ₂ F ₄ O) _n —CF ₂ —CH ₂ —OH ( It was confirmed that n = 5, 6).
Table 1 shows the detailed conditions of the steps (1a), (1b) and (3) to (5).

[Example 2]
In the same manner as the raw material preparation step of Example 1 and steps (1) to (5), except that a PEG mixture having a repetition number of 9 and 10 was used and the conditions shown in Table 1 were adopted. A fluoropolyether compound was produced to obtain 17.9 g of the product (2-ii). As a result of analyzing the obtained product (2-ii) by ¹⁹ F NMR, CH ₃ O—CO—CF ₂ —O— (C ₂ F ₄ O) _n —CF ₂ —CO—OCH ₃ (n = 7 8).

[Example 3]
In the same manner as in the raw material preparation step and steps (1) to (5) of Example 1 except that Wako Pure Chemical Industries polyethylene glycol 600 was used and the conditions shown in Table 1 were adopted, perfluoropolyethylene was used. An ether compound was produced to obtain 17.0 g of the product (3-ii). As a result of analyzing the obtained product (3-ii) by ¹⁹ F NMR, it was confirmed that it was CH ₃ O—CO—CF ₂ —O— (C ₂ F ₄ O) _n —CF ₂ —CO—OCH _3. confirmed.

[Comparative Example 1]
In Comparative Example 1, CH ₃ CO—O— (C ₂ H ₄ O) _n —COCH ₃ (n = 6) was used instead of the product (1-i) obtained in the raw material preparation step of Example 1. Except that the steps (1b), (2) and (3) were not carried out, generally in the same manner as the steps (1a), (4) and (5) of Example 1 An attempt was made to produce the compound. Specifically, it is as follows.

Into a 1 L autoclave, 35 g of NaF and 400 mL of HFTCB were introduced and sealed. Stirring in the autoclave was started, and nitrogen gas was purged through the autoclave at 800 mL / min for 1 hour. While circulating nitrogen gas at 800 mL / min, the autoclave was immersed in a refrigerant cooled to −10 ° C., and the autoclave was cooled to about −10 ° C. Fluorine gas was circulated at 200 mL / min, and the inside of the autoclave was purged with 20 vol% fluorine gas. While flowing fluorine gas at 200 mL / min and nitrogen gas at 800 mL / min, 4.9 g of CH ₃ CO—O— (C ₂ H ₄ O) _n —COCH ₃ (n = 6) was dissolved in 200 mL of HFTCB and 3 Circulated at a flow rate of 3 mL / min.

Stirring in the autoclave was started, and the autoclave was heated with an external heater so that the temperature inside the autoclave was about 30 ° C. Nitrogen gas was circulated in the autoclave at 450 mL / min and fluorine gas at 50 mL / min to start the fluorination reaction, and about 1.5 g of C ₆ F ₆ was dissolved in 30 mL of HFTCB and introduced at 0.5 mL / min. did.

After introducing C ₆ F ₆ into circulation, the circulation of fluorine gas was stopped, and nitrogen gas was circulated at 450 mL / min for 1 hour to purge the autoclave. The nitrogen gas flow was stopped, and 40 g of methanol was introduced under a nitrogen atmosphere of 0.1 MPaA in the autoclave. After stirring the autoclave for 30 minutes, the reaction solution was recovered. The solvent was distilled off from the recovered reaction solution with an evaporator to obtain 3.5 g of a recovered solution. As a result of analyzing the obtained recovered liquid by ¹⁹ F NMR, a peak having a terminal —CF ₃ was detected, and as a result of LC analysis, CH ₃ O—CO—CF ₂ —O— (C ₂ F ₄ O) _n — CF ₂ —CO—OCH ₃ is 40%, CH ₃ O—CO—CF ₂ —O— (C ₂ F ₄ O) _n —CF ₃ is 25%, and impurities that are considered to be insufficiently fluorinated are 35%. % Was detected.
Detailed conditions in each step are shown in Table 1.

[Comparative Example 2]
In Comparative Example 2, CH ₃ CO—O— (C ₂ H ₄ O) _n —COCH ₃ (n = 6) was used instead of the product (1-i) obtained in the raw material preparation step of Example 1. In the same manner as in steps (1a) and (5) of Example 1, except that steps (1b) and (2) to (4) were not performed, a perfluoropolyether compound was produced. Tried. Specifically, it is as follows.

Into a 1 L autoclave, 35 g of NaF and 400 mL of HFTCB were introduced and sealed. Stirring in the autoclave was started, and nitrogen gas was purged through the autoclave at 800 mL / min for 1 hour. While circulating nitrogen gas at 800 mL / min, the autoclave was immersed in a refrigerant cooled to −10 ° C., and the autoclave was cooled to about −10 ° C. Fluorine gas was circulated at 200 mL / min, and the inside of the autoclave was purged with 20 vol% fluorine gas. While passing fluorine gas at 200 mL / min and nitrogen gas at 800 mL / min, 4.0 g of CH ₃ CO—O— (C ₂ H ₄ O) _n —COCH ₃ (n = 6) was dissolved in 200 mL of HFTCB and 3 Circulated at a flow rate of 3 mL / min.

After introducing CH ₃ CO—O— (C ₂ H ₄ O) _n —COCH ₃ (n = 6), the flow of fluorine gas was stopped, and nitrogen gas was passed at 450 mL / min for 1 hour to autoclave The inside was purged. The nitrogen gas flow was stopped, and 40 g of methanol was introduced under a nitrogen atmosphere of 0.1 MPaA in the autoclave. After stirring the autoclave for 30 minutes, the reaction solution was recovered. The solvent was distilled off from the recovered reaction liquid with an evaporator to obtain 3.6 g of a recovered liquid. As a result of analyzing the obtained recovered liquid by LC, CH ₃ O—CO—CF ₂ —O— (C ₂ F ₄ O) _n —CF ₂ —CO—OCH ₃ was not detected and fluorination was insufficient. Possible impurities were detected in 99%.
Detailed conditions in each step are shown in Table 1.

Claims (6)

A step (1) of introducing a compound represented by the following formula (i), a hydrogen fluoride scavenger, an inert gas, a fluorine gas, and a solvent into the reactor;
After step (1), removing hydrogen fluoride scavenger from the reactor (2);
A step (3) of passing an inert gas and a fluorine gas through the reactor after the step (2);
A method for fluorinating a compound represented by the following formula (i), comprising a step (4) of circulating a perhalogen unsaturated compound in the reactor while performing the step (3).
R ¹ —O— (R—O—) _n —R ² (i)
[In the formula (i), (R—O—) represents a linear or branched repeating unit having 2 to 3 carbon atoms, R ¹ and R ² represent a hydroxyl-protecting group, and n represents 4 to 20 Represents an integer. ] The fluorination method according to claim 1, wherein R ¹ and R ² are acyl groups.   The fluorination method according to claim 1 or 2, wherein the hydrogen fluoride scavenger is an alkali metal fluoride.   The fluorination method according to any one of claims 1 to 3, wherein the solvent in the step (1) is a completely halogen-substituted compound. Including the fluorination method according to any one of claims 1 to 4, and
The manufacturing method of the compound represented by following formula (ii) including the process (5) which introduce | transduces C1-C3 alcohol into the said reactor after the said process (4), and performs esterification reaction.
_{^{R 3 O-CO-CF 2}} -O- (Rf) n-2 -CF 2 -CO-OR 4 (ii)
[In Formula (ii), R ³ and R ⁴ represent an alkyl group having 1 to 3 carbon atoms, and Rf represents a perfluoropolyether in which all hydrogen atoms of R in Formula (i) are substituted with fluorine atoms. Represents a chain, and n represents an integer of 4 to 20. ] The manufacturing method of the compound represented by following formula (iii) including the process (6) which reduces the compound obtained by the manufacturing method of Claim 5 with a metal borohydride.
HO—CH ₂ —CF ₂ —O— (R f) _n−2 —CF ₂ —CH ₂ —OH (iii)
[In the formula (iii), Rf and n have the same meanings as Rf and n in the formula (ii). ]