JPWO2006054549A1 - Production method of fluorine-containing 2-chloroacrylate - Google Patents

Abstract

Fluorine-containing 2,3-dichloropropionic acid ester is contacted with an alkaline compound in the presence of a catalytic amount of a nitrogen-containing basic compound and / or a salt of the nitrogen-containing basic compound to remove hydrochloric acid, and fluorine-containing 2-chloroacrylic acid is obtained. A fluorine-containing 2-chloroacrylic acid ester is produced by obtaining an acid ester.

Description

  The present invention relates to a method for producing a fluorine-containing 2-chloroacrylic acid ester.

Examples of the method for synthesizing 2,3-dichloropropionic acid alkyl ester include the following.
JACS 62,3495 (1940) is chlorinated with chlorine in a methanol solvent,
Japanese Examined Patent Publication No. 33-5966 discloses reacting amide as a catalyst in a gas phase reaction,
Japanese Patent Publication No. 61-21542 discloses chlorination using monohydrogen phosphate / alkali metal salt as a catalyst,
Japanese Examined Patent Publication No. 7-17578 discloses chlorination using a tertiary amine or a tertiary phosphine.
Examples of the dehydrochlorination reaction of 2,3-dichloropropionic acid alkyl ester include the following.
Japanese Patent Publication No. 43-18365 discloses dehydrochlorination using ammonia,
Japanese Patent Publication No. 43-18366 discloses dehydrochlorination using a metal alkoxide,
Japanese Patent No. 3555775 describes dehydrochlorination using an aqueous base,
JP-A-10-273473 discloses dehydrochlorination using an aqueous base.
However, none of the conventional methods can efficiently produce a fluorine-containing 2-chloroacrylate.

Japanese Patent Publication No.33-5966 Japanese Patent Publication No. 61-21542 Japanese Patent Publication No. 7-17578 Japanese Patent Publication No.43-18365 Japanese Patent Publication No.43-18366 Japanese Patent No.3055775 JP-A-10-273473 JACS 62,3495 (1940)

  An object of the present invention is to produce a fluorine-containing 2-chloroacrylic acid ester as an industrial process practically at low cost and efficiently.

  In the present invention, fluorine-containing 2,3-dichloropropionic acid ester is contacted with an alkaline compound in the presence of a catalytic amount of a nitrogen-containing basic compound to dehydrochlorinate to obtain fluorine-containing 2-chloroacrylic acid ester. A method for producing a fluorine 2-chloroacrylate ester is provided.

  According to the present invention, a fluorine-containing 2-chloroacrylic acid ester can be obtained in a high yield by a simple operation.

Fluorine-containing 2,3-dichloropropionic acid ester is a gaseous chlorine in the presence of a fluorinated acrylic acid ester in the presence of a chlorination catalyst selected from the group consisting of tertiary amines, tertiary amine salts and N-substituted amides. It can be produced by chlorination with
The present invention
(A) Step of synthesizing fluorine-containing 2,3-dichloropropionic acid ester from fluorine-containing acrylic acid ester, and (B) Synthesis of fluorine-containing 2-chloroacrylic acid ester from fluorine-containing 2,3-dichloropropionic acid ester. There is also provided a manufacturing method having a process.
According to the present invention, it is not necessary to isolate the intermediate product in any step, and the step (A) and the step (B) are continuously performed to convert the fluorine-containing acrylic ester to the fluorine-containing 2-chloroacrylic acid. Esters can be synthesized.

The fluorine-containing acrylic ester used as a starting material has the formula:
Rf-A-O-C ( = O) -CH = CH 2 (1)
[Rf is a fluoroalkyl group having 1 to 21 carbon atoms;
A is a C1-C30 bivalent organic group which may have at least one of an oxygen atom or a nitrogen atom. ]
It may be a compound shown by these.

  Rf is preferably a perfluoroalkyl group. Rf may have 1 to 20 carbon atoms, for example 1 to 6, in particular 1 to 5, particularly 1 to 4.

An example of A is as follows, for example.
Direct bond-(CH ₂ ) _p-
-CONR ¹¹ -R ¹² -
—CH ₂ C (OH) HCH ₂ —
^{_{-CH 2 C (OCOR 13) HCH}} 2 - , or -O-Ar-CH ₂ -

[Wherein R ¹¹ is hydrogen or an alkyl group having 1 to 10 carbon atoms,
R ¹² is an alkylene group having 1 to 10 carbon atoms,
R ¹³ is hydrogen or a methyl group,
Ar is an arylene group (having 6 to 20 carbon atoms) which may have a substituent,
p is an integer of 1 to 10, for example, 1 to 4. ]

The fluorine-containing 2,3-dichloropropionic acid ester obtained in the step (A) has the formula:
Rf-A-O-C ( = O) -CHCl-CH 2 Cl (2)
[Rf and A are as defined above. ]
It may be a compound shown by these.

The fluorine-containing 2-chloroacrylic acid ester obtained in the step (B) has the formula:
Rf-A-O-C ( = O) -CCl = CH 2 (3)
[Rf and A are as defined above. ]
It may be a compound shown by these.

Step (A) will be described.
Chlorination of the fluorine-containing acrylic acid ester can be easily performed without the presence of a solvent. If necessary, an organic solvent in which the fluorine-containing acrylic acid ester is preferably dissolved may be used. Examples of organic solvents are chlorinated inert organic solvents such as alcohols, ketones, esters, ethers and the like. The amount (weight) of the organic solvent may be 0.01 to 100 times, particularly 0.2 to 10 times with respect to the weight of the fluorine-containing acrylic ester.

  The addition reaction of chlorine is preferably performed in a light-shielded state. Chlorination can be carried out by directly adding gaseous chlorine to the fluorinated acrylic ester in the presence of a chlorination catalyst. Examples of preferred chlorination catalysts are tertiary amines such as trimethylamine, triethylamine, tripropylamine, tributylamine; N-substituted amides such as dimethylformamide; aromatic nitrogen-containing compounds (particularly aromatic nitrogen-containing heterocyclic compounds) (I.e. compounds in which the aromatic ring is formed by (e.g. 4 or more) carbon atoms and at least one (e.g. 1 or 2) nitrogen atoms)), e.g. pyridine, alkylpyridine (carbon of the alkyl group) Number: for example 1 to 10) (especially methylpyridine). The chlorination catalyst may be a salt (ie a salt of a tertiary amine), in particular a salt of an organic or inorganic acid, for example the hydrochloride. The chlorination catalyst is usually used in an amount of 0.01 to 10 parts by weight, preferably 3 to 8 parts by weight, based on 100 parts by weight of the fluorine-containing acrylic ester. The reaction temperature for carrying out the chlorination may be 30-100 ° C., for example 40-80 ° C., generally 50 ° C.-80 ° C., preferably 50 ° C.-70 ° C., in particular 55 ° C.-65 ° C., in particular 60 ° C. . The reaction time of the chlorination reaction may be 0.5 to 24 hours, for example 6 to 12 hours. The chlorination reaction is preferably carried out by bringing a liquid phase fluorine-containing acrylate ester into contact with gas phase chlorine. The chlorination reaction can be carried out by bubbling chlorine gas into the fluorinated acrylate liquid while stirring. One mole or more, for example, 1.0 to 1.2 moles of chlorine gas may be blown over 0.5 to 24 hours, for example, 6 to 12 hours, with respect to 1 mole of the fluorine-containing acrylic ester. In chlorination, oxygen gas (concentration: for example, 1000 ppm to 18%) may be present in the gas phase on the reaction system (liquid phase).

Step (B) will be described.
Step (B) may be carried out without the need to isolate the intermediate fluorine-containing 2,3-dichloropropionic acid ester from the reaction mixture obtained in step (A). In step (B), 2,3-dichloropropionic acid ester is dehydrochlorinated with an alkaline compound in the presence of a dehydrochlorination catalyst that is a nitrogen-containing basic compound or a salt thereof. The dehydrochlorination catalyst is preferably an organic compound (particularly a compound having at least one (for example, 1 to 20) carbon atoms). Examples of dehydrochlorination catalysts are amines, especially tertiary amines, and aromatic nitrogen-containing compounds. Examples of tertiary amines are trimethylamine, triethylamine, tripropylamine, tributylamine, triethanolamine. Examples of aromatic nitrogen-containing compounds (particularly aromatic nitrogen-containing heterocyclic compounds) are pyridine and alkylpyridine (carbon number of alkyl group: for example, 1 to 10) (particularly methylpyridine). The dehydrochlorination catalyst may be a salt (a salt of a nitrogen-containing basic compound), specifically, a salt of an organic acid or an inorganic acid, such as a hydrochloride. The amount of the dehydrochlorination catalyst was 0.001 mol, for example 0.01 mol, and the upper limit was 0.5 mol, for example 0.1 mol, relative to 1 mol of fluorine-containing 2,3-dichloropropionic acid ester. It's okay. When a tertiary amine or an aromatic nitrogen-containing compound is used as the chlorination catalyst, the catalyst added when chlorinating can be used as it is as a catalyst for dehydrochlorination. Triethylamine is particularly preferable as the catalyst for dehydrochlorination.
When a dehydrochlorination catalyst is not used for dehydrochlorination, the conversion rate of the raw material is low even if the dehydrochlorination reaction takes a long time, and an alkaline compound is required to increase the conversion rate, which is economically disadvantageous. Further, in the case of no catalyst, hydrolysis of the ester proceeds to produce undesired alcohols as a by-product, resulting in a decrease in yield.

  Examples of alkaline compounds are sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, ammonium hydroxide, and mixtures thereof. In particular, sodium hydroxide and potassium hydroxide are particularly preferable. The alkaline compound should be used in an amount of at least 1 mol, for example, 1.0 to 1.3 mol, particularly 1.05 to 1.1 mol, per 1 mol of fluorine-containing 2,3-dichloropropionic acid ester. Can do. In general, the alkaline compound is used in the form of an aqueous solution dissolved in water. The concentration of the alkaline compound in the aqueous solution of the alkaline compound may be 1 to 50% by weight, for example 10 to 30% by weight.

The dehydrochlorination reaction is usually performed at a temperature of -10 ° C to 50 ° C, preferably 0 ° C to 30 ° C. The dehydrochlorination reaction is usually performed for 0.5 to 12 hours, for example, 2 to 6 hours. Usually, the alkaline compound is preferably added in an amount and a rate so that alkaline (for example, pH 7.2 to 11.0) conditions are maintained throughout the dehydrochlorination reaction, but the system is neutral or acidic. (For example, pH 5.0-6.8) The quantity and speed | rate which become conditions may be sufficient.
It is desirable to add a polymerization inhibitor before the dehydrochlorination reaction in order to prevent polymerization. As the polymerization inhibitor, t-butylcatechol, hydroquinone, hydroquinone monomethyl ether, phenothiazine, or the like is used. The polymerization inhibitor is usually added in an amount of 30 to 1000 ppm based on the weight of the fluorine-containing 2,3-dichloropropionic acid ester.

  After the dehydrochlorination reaction is complete, acid is added to the reaction mixture to adjust the pH of the reaction mixture to 7 or less. Examples of acids are organic or inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, p-toluenesulfonic acid and the like. The pH of the reaction mixture is adjusted to, for example, 1 to 5, preferably 3 to 5. The pH adjustment is usually performed at a temperature of −10 ° C. to 50 ° C., preferably 0 ° C. to 30 ° C.

  When the pH-adjusted reaction mixture is allowed to stand, it is separated into an aqueous layer (upper layer) and an oil layer (lower layer). The oil layer contains a fluorine-containing 2-chloroacrylate ester which is the target product.

Example 1
400 g of 2- (perfluorobutyl) ethyl acrylate, 5.1 g of triethylamine, and 0.01 g of t-butylcatechol are placed in a four-necked flask (the gas phase above the mixed liquid charged is air), and a water bath. Was heated to 60 ° C., and 99 g of chlorine gas was blown in for 12 hours in a light-shielded state. A reaction solution containing 2,3-dichloropropionic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) with a purity of 98% or more was obtained.
358 g of water was added to the reaction solution, and 143 g of 30% aqueous sodium hydroxide solution was added dropwise over 2 hours while stirring in an ice bath and stirring. While dropping, the temperature was not allowed to exceed 7 ° C. After dropping, the mixture was stirred for 1 hour, and 35% hydrochloric acid was added to adjust the pH to 3 while stirring. The reaction mixture was transferred to a separatory funnel and heated to 60 ° C. After standing for 30 minutes, the lower layer 2-chloro-2-propenoic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) was taken out. 2-Chloro-2-propenoic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) was obtained by gas chromatography-purity 95%, yield 421 g.

Example 2
A pressure-resistant glass reactor having a stirrer and a heater was charged with 400 g of 2- (perfluorobutyl) ethyl acrylate, 3.68 g of dimethylformamide, and 0.01 g of t-butylcatechol, and heated to 50 ° C. With the reactor shielded from light, 93.6 g of chlorine gas was blown in over 11 hours. A reaction solution containing 2,3-dichloropropionic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) with a purity of 97% or more was obtained.
371 g of water and 6.6 g of triethylamine hydrochloride were added to the reaction solution, and 187 g of a 30% aqueous sodium hydroxide solution was added dropwise over 2 hours with stirring and cooling in an ice bath. While dropping, the temperature was not allowed to exceed 7 ° C. After dropping, the mixture was stirred for 1 hour, and 35% hydrochloric acid was added to adjust the pH to 3 while stirring. The reaction mixture was transferred to a separatory funnel and allowed to stand for 30 minutes, and then the lower layer 2-chloro-2-propenoic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) was taken out. A yield of 413 g of 2-chloro-2-propenoic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) was obtained with a gas chromatography purity of 93%.

Example 3
A pressure-resistant glass reactor having a stirrer and a heater was charged with 400 g of 2- (perfluorobutyl) ethyl acrylate, 3.68 g of dimethylformamide, and 0.01 g of t-butylcatechol, and heated to 50 ° C. With the reactor shielded from light, 93.6 g of chlorine gas was blown in over 11 hours. After blowing in chlorine, the mixture was stirred for 4 hours. A reaction solution containing 2,3-dichloropropionic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) with a purity of 97% or more was obtained.
To the reaction solution, 184 g of water and 6.6 g of triethylamine hydrochloride were added, and the mixture was cooled in an ice bath and added dropwise with 107 g of 48% aqueous sodium hydroxide over 2 hours while stirring. While dropping, the temperature was not allowed to exceed 7 ° C. After dropping, the mixture was stirred for 1 hour, and 35% hydrochloric acid was added to adjust the pH to 3 while stirring. The reaction mixture was transferred to a separatory funnel and allowed to stand for 30 minutes, and then the lower layer 2-chloro-2-propenoic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) was taken out. A yield of 411 g of 2-chloro-2-propenoic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) was obtained with a gas chromatography purity of 94%.

Example 4
A pressure-resistant glass reactor having a stirrer and a heater is charged with 400 g of 2- (perfluorobutyl) ethyl acrylate, 5.19 g of N-methyl-2-pyrrolidone, and 0.01 g of t-butylcatechol, and heated to 50 ° C. did. With the reactor shielded from light, 93.6 g of chlorine gas was blown in over 11 hours. After blowing in chlorine, the mixture was stirred for 4 hours. A reaction solution containing 2,3-dichloropropionic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) with a purity of 97% or more was obtained.
To the reaction solution, 184 g of water and 6.6 g of triethylamine hydrochloride were added, and 112 g of 48% aqueous sodium hydroxide solution was added dropwise over 2 hours while cooling in an ice bath and stirring. While dropping, the temperature was not allowed to exceed 7 ° C. After dropping, the mixture was stirred for 1 hour, and 35% hydrochloric acid was added to adjust the pH to 3 while stirring. The reaction mixture was transferred to a separatory funnel and allowed to stand for 30 minutes, and then the lower layer 2-chloro-2-propenoic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) was taken out. A yield of 401 g of 2-chloro-2-propenoic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) was obtained with a gas chromatography purity of 95%.

Example 5
A pressure-resistant glass reactor having a stirrer and a heater was charged with 400 g of 2- (perfluorobutyl) ethyl acrylate, 6.9 g of triethylamine hydrochloride, and 0.01 g of t-butylcatechol, and heated to 50 ° C. With the reactor shielded from light, 93.6 g of chlorine gas was blown in over 11 hours. A reaction solution containing 2,3-dichloropropionic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) with a purity of 96% or more was obtained.
To the reaction solution, 184 g of water was added, and cooled with an ice bath, and a 48% sodium hydroxide aqueous solution was added dropwise over 112 hours while stirring. While dropping, the temperature was not allowed to exceed 7 ° C. After dropping, the mixture was stirred for 1 hour, and 35% hydrochloric acid was added to adjust the pH to 3 while stirring. The reaction mixture was transferred to a separatory funnel and allowed to stand for 30 minutes, and then the lower layer 2-chloro-2-propenoic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) was taken out. A yield of 408 g of 2-chloro-2-propenoic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) was obtained with a gas chromatography purity of 93%.

Comparative Example 1
In Example 3, the same operation was performed except that triethylamine hydrochloride was not added. Two hours after adding sodium hydroxide dropwise, analysis using gas chromatography revealed that gas chromatography of 2-chloro, 2-propenoic acid- (1H, 1H, 2H, 2H-nonafluorohexyl) -purity 75% And the reaction was not completed.

Claims (13)

  Fluorine-containing 2,3-dichloropropionic acid ester is contacted with an alkaline compound in the presence of a catalytic amount of a nitrogen-containing basic compound and / or a salt of the nitrogen-containing basic compound to remove hydrochloric acid, and fluorine-containing 2-chloroacrylic acid is obtained. The manufacturing method of fluorine-containing 2-chloroacrylic acid ester which obtains acid ester.   The fluorine-containing acrylic acid ester is chlorinated with gaseous chlorine in the presence of at least one chlorination catalyst selected from the group consisting of tertiary amines, tertiary amine salts and N-substituted amides, to give fluorine-containing 2 A fluorine-containing 2-chloroacrylic acid ester obtained by obtaining a fluorine-containing 2-chloroacrylic acid ester from a fluorine-containing 2,3-dichloropropionic acid ester by the method according to claim 1 after obtaining 1,3-dichloropropionic acid ester Manufacturing method. The fluorine-containing acrylic ester has the formula:
Rf-A-O-C ( = O) -CH = CH 2 (1)
[Rf is a fluoroalkyl group having 1 to 21 carbon atoms;
A is a C1-C30 bivalent organic group which may have at least one of an oxygen atom or a nitrogen atom. ]
The method of Claim 2 which is a compound shown by these. Fluorine-containing 2,3-dichloropropionic acid ester has the formula:
Rf-A-O-C ( = O) -CHCl-CH 2 Cl (2)
[Rf is a fluoroalkyl group having 1 to 21 carbon atoms;
A is a C1-C30 bivalent organic group which may have at least one of an oxygen atom or a nitrogen atom. ]
The method of Claim 1 which is a compound shown by these. The fluorine-containing 2-chloroacrylic acid ester has the formula:
Rf-A-O-C ( = O) -CCl = CH 2 (3)
[Rf is a fluoroalkyl group having 1 to 21 carbon atoms;
A is a C1-C30 bivalent organic group which may have at least one of an oxygen atom or a nitrogen atom. ]
The method of Claim 1 which is a compound shown by these.   The method according to claim 1, wherein the nitrogen-containing basic compound is selected from the group consisting of a tertiary amine and an aromatic nitrogen-containing heterocyclic compound.   The process according to claim 1 or 2, wherein triethylamine is used as the chlorination catalyst and / or the nitrogen-containing basic compound.   The method according to claim 1, wherein the amount of the nitrogen-containing basic compound is 0.001 to 0.5 mol with respect to 1 mol of the fluorine-containing alkyl ester of 2,3-dichloropropionic acid.   The method according to claim 1, wherein the alkaline compound is selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonium hydroxide and sodium carbonate.   The process according to claim 2, wherein all reactions are carried out without isolation of the intermediate product.   The method according to claim 10, wherein after the reaction with the alkaline compound, the reaction mixture is acidified to perform a liquid separation treatment.   The process according to claim 11, wherein the pH of the reaction mixture is 1 to 5 for acidification. The method according to claim 1 or 2, wherein the chlorination is carried out in the presence of oxygen gas.