JPH0342258B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a new and useful fluorine-containing carboxylic acid ester. The present invention [In the formula, m represents an integer of 4 to 11] A cyclic ketone represented by the following is reacted with hydrogen peroxide in a saturated lower alcohol, and then the resulting cyclic ketone peroxide is expressed by the general formula [In the formula, R _f represents a fluoroalkyl group having 1 to 11 carbon atoms] or general formula [In the formula, R ₃ represents a methyl group or a trifluoromethyl group] A monomer represented by the following is reacted in the presence of a ferrous salt to form the general formula R ₁ -A-R ₂ () [In the formula, A is

【formula】

[Formula] or -(OR _f = CH-( _o (R _f is a fluoroalkyl group having 1 to 11 carbon atoms,
R ₃ is a methyl group or a trifluoromethyl group, n
is an integer of 1 to 3), and R ₁ and R ₂ are the same or different and represent a hydrogen atom,
Fluorine atom, R ₄ OOC(CH ₂ ) _n (R ₄ is a lower alkyl group, m is an integer from 4 to 11), R _f CH=CH- or
CF ₃ CR ₃ =CH− (R _f and R ₃ are the same as above). However, R ₁ and R ₂ are not hydrogen atoms, fluorine atoms, R _f CH=CH- or CF ₃ CR ₃ =CH- at the same time, and at least one of R ₁ and R ₂ is R ₄ OOC—(CH ₂ —) _n] The present invention provides a method for producing a fluorine-containing carboxylic acid ester, which is characterized by obtaining an ester represented by the following formula. The lower alkyl group herein refers to an alkyl group having 1 to 4 carbon atoms. The fluorine-containing carboxylic acid ester of the general formula () obtained by the present invention is useful as a raw material for the synthesis of paints, plastics, fibers, etc., and as a raw material for the synthesis of surfactants, emulsifiers, etc. General formula () used in the production method of the present invention
The monomer represented by (') has >C=CH bonded to the fluorine-containing group, so it has an affinity for the cyclic ketone in the reaction with the cyclic ketone, and therefore has high reactivity. The invented method is excellent as an industrial synthesis method. In the reaction between the cyclic ketone represented by the general formula () and hydrogen peroxide, the ratio of the two to be used is not particularly limited and may be appropriately selected within a wide range, but usually the latter is 0.5 to 0.5 to It is preferable to use about twice the molar amount, preferably about the same molar amount. Specific examples of the cyclic ketone of general formula () include cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone, cyclodecanone, cycloundecanone, and cyclododecanone. Further, hydrogen peroxide is usually used in the form of an aqueous solution with a concentration of about 30 to 70%. The reaction is preferably carried out in a suitable solvent.
Examples of the solvent include saturated lower alcohols such as methanol, ethanol, isopropanol, n-butanol, and tert-butanol. Among these, it is preferable to use methanol, particularly anhydrous methanol, and the reaction is preferably carried out in the presence of an acid catalyst, whereby the yield of cyclic ketoperoxides can be further improved. Examples of the acid catalyst include mineral acids such as sulfuric acid, hydrochloric acid, and phosphoric acid, preferably sulfuric acid. The amount of the acid catalyst to be used is usually 0.05 to 0.5 mol per mol of the cyclic ketone of general formula (). The reaction is generally carried out at -70°C to 50°C, preferably -10°C to
The reaction is carried out at 20°C and usually completes in about 5 to 60 minutes. In this way, cyclic ketone peroxides are produced. In the present invention, cyclic ketone peroxides may be isolated from the above reaction product and subjected to the next reaction, or the above reaction product may be used as is or after being concentrated for the next reaction. The monomers represented by the above general formula () or (') to be reacted with the cyclic ketone peroxide include CF ₃ CF ₂ CH=CH ₂ CF ₃ (CF ₂ ) ₅ CH=CH ₂ CF ₃ (CF ₂ ) ₉ CH ＝ _CH2

【formula】

【formula】

【formula】

【formula】

[Formula] etc. In the reaction between cyclic ketone peroxides and monomers of general formula () or (') above, the proportion of the two used is not particularly limited and may be appropriately selected within a wide range; The latter is preferably used in an equimolar to 8-fold molar amount, preferably in a 2- to 4-fold molar amount. The reaction is preferably carried out in a suitable solvent. As the solvent, the same solvent as used in the reaction between the cyclic ketone and hydrogen peroxide can be used. The reaction is carried out in the presence of ferrous salts. Examples of ferrous salts include ferrous sulfate, ferrous chloride, and ferrous ammonium sulfate. The ferrous salt is generally used in an amount of 0.1 to 2 moles, preferably 0.8 to 1.2 moles, per mole of the cyclic ketone peroxide. In a preferred embodiment of the reaction, for example, a predetermined amount of the monomer of general formula () or (') is added to a solvent and the temperature is generally -70 to 50°C, preferably -10 to -20°C.
It is preferable to form a suspension solution by stirring at a temperature of .degree. C., and then add a predetermined amount of ferrous salt to the suspension solution, and then dropwise dropwise add the cyclic ketone peroxide produced above while stirring. If this reaction is carried out in a nitrogen gas stream, the yield of the target product can be further improved. The reaction time for this reaction is generally about 1 to 7 hours. The cyclic ketone peroxides produced when a cyclic ketone and hydrogen peroxide are reacted in a lower alcohol are lower alkoxy cyclic ketone peroxides, and therefore, the following lower alkoxy cyclic ketone peroxides and the general formula ( ) or (') produces a fluorine-containing carboxylic acid ester represented by the general formula () as a product. The fluorine-containing carboxylic acid ester of the general formula () thus produced can be easily isolated and purified by conventionally known separation means, such as solvent extraction and distillation. Olefins, solvents, etc. are recovered by a simple distillation operation and reused. The thus obtained fluorine-containing carboxylic acid ester represented by the general formula () is a new compound that has not been described in any literature. Conventionally, compounds obtained by oxidizing telomer of tetrafluoroethylene and methanol have been known as fluorine-containing carboxylic acids, but these compounds are only compounds in which a carboxyl group is directly bonded to a fluorine-containing functional group. do not have. On the other hand, the fluorine-containing carboxylic acid ester represented by the general formula () of the present invention has a long chain methylene group or a vinyl group and a long chain methylene group between the fluorine-containing functional group and the carboxyl group. It has a different chemical structure from conventionally known compounds. The fluorine-containing carboxylic acid ester represented by the general formula () of the present invention is used for various purposes, but
For example, a synthetic resin prepolymer (eg, an epoxy resin prepolymer, a urethane resin prepolymer, etc.) synthesized by adding the compound can be made into an emulsion with extremely excellent emulsifying properties. The synthetic resin prepolymer can be used, for example, as an emulsion paint. Furthermore, if the synthetic resin prepolymer is used as a resin component, excellent antifouling properties can be imparted to the resulting paints, plastics, fibers, etc. Therefore, the fluorine-containing carboxylic acid ester of the present invention represented by the general formula () is useful as a synthetic raw material for paints, plastics, fibers, etc. The compound is also useful as a synthetic raw material for surfactants, emulsifiers, and the like. Representative examples of the fluorine-containing carboxylic acid esters represented by the above general formula () are listed in Table 1 below.

[Table] ｜
CF ₃

[Table] The present invention will be further explained with reference to Examples below. Example 1 600ml of anhydrous methanol was placed in a reactor equipped with a stirrer,
Cool to 0-5℃ and add 120g of cyclohexanone.
(1.22 mol), 3.0 g of concentrated sulfuric acid, and 120 g of 35% aqueous hydrogen peroxide solution were added, and stirring was continued for 60 minutes to produce methoxycyclohexanone peroxide. 600 ml of anhydrous methanol was placed in another stirred reactor through which nitrogen gas was passed, cooled to -10°C, and then 340 g of ferrous sulfate (heptahydrate) and hexafluoroisobutene were added.
Add 300 g (1.83 mol) to form a suspension. This suspension was cooled to -10°C, and the above methoxycyclohexanone peroxide-containing solution was gradually added dropwise with stirring. After the dropwise addition was completed, stirring was continued for 2 hours, and then the reaction solution was naturally heated to room temperature. After distilling off the methanol, the organic layer (upper layer) is separated. After washing with acid and water, it was dried to obtain 410 g of a pale yellow oily crude product. The crude ester was distilled to give the next batch. (1) Boiling point 50-72℃/15mmHg 23.7g (5.8wt%) Main component Methyl caproate (2) Boiling point 102℃/15mmHg 96.3g (23.5wt%) MW294 Mass: m/e=294 (M ⁺ ) 264 (M ⁺ −OCH ₃ ) 59 (COOCH ₃ ) ¹ HNMR (CDCl ₃ ): δ1.2~2.0 (10H, m, −CH ₂ −) 2.30 (2H, t, J=7.3Hz, −CH ₂ CO−) 2.86 (1H, d− sep, J=6.0, 8.4Hz, >CH
−) 3.65 (3H, s, −OCH ₃ ) ¹⁹ FNMR (CDCl ₃ ) Ext, TFA δ−11.8 (6F, d, J=8.9Hz, CF ₃ ) (3) Boiling point 135-145℃/15mmHg 46.0g ( 11.2wt%) MW458 25.3g Mass: m/e=458 (M ⁺ ) 427 (M ⁺ −OCH ₃ ) 59 (COOCH ₃ ) MW622 12.8g Mass: m/e=622 (M ⁺ ) 591 (M ⁺ −OCH ₃ ) 59 (COOCH ₃ ) MW456 0.1g Mass: m/e=456 (M ⁺ ) 425 (M ⁺ −OCH ₃ ) 59 (COOCH ₃ ) MW620 7.8g Mass: m/e=620 (M ⁺ ) 589 (M ⁺ −OCH ₃ ) 59 (COOCH ₃ ) (4) Still residue Boiling point 145℃/15mmHg (or more) 244g (59.5wt%) MW456 8.8g 3 isomers MW620 58.0g 2 isomer MW622 17.8g 95.4g Example 2 Put 250 ml of anhydrous methanol into a reactor equipped with a stirrer,
Cool to 0-5℃ and add 63g (0.64mol) of cyclohexanone, 15g of concentrated sulfuric acid and 63g of 35% hydrogen peroxide.
Continue stirring for 60 minutes to generate methoxycyclohexanone peroxide. Add 250 ml of anhydrous methanol to another reactor with a stirrer through which nitrogen gas is passed.
Cool to 10℃, then add ferrous sulfate (heptahydrate) 142
g and 140 g (0.31 mol) of C ₈ F ₁₇ CH=CH ₂ to form a suspension. This suspension is cooled to 0 to 5°C, and the methoxycyclohexanone peroxide-containing solution is gradually added dropwise while stirring. After the dropwise addition was completed, stirring was continued for 2 hours, and then the reaction solution was naturally heated to room temperature. After methanol was distilled off, the lower layer was separated, washed with acid, washed with water, and dried to obtain 200 g of a pale yellow oily crude product.
This is the result of gas chromatography analysis.
It contained the following ingredients: (1) Low boiling point component 10.2g (2) C ₈ F ₁₇ CH=CH ₂ 60.6g (3) C ₈ F ₁₇ CH ₂ CH ₂ (CH ₂ ) ₅ COOCH ₃ MW576 20.8g Mass: m/e=576 ( (M ⁺ ) 545 (M ⁺ −OCH ₃ ) 59 (COOCH ₃ ) (4) C ₈ F ₁₇ −CH=CH (CH ₂ ) ₅ COOCH ₃ MW574 30.8g Mass: m/e=574 (M ⁺ ) 543 (M ⁺ −OCH ₃ ) 59 (COOCH ₃ ) MW704 57.6g Others 20.0g Example 3 An experiment was carried out in the same manner as in Example 1 except that the amount of hexafluoroisobutene used relative to cyclohexanone was changed, and the results shown in Table 2 below were obtained.

[Table] As a result of experiments using hexafluoropropene according to the conventional method (method described in Example 1 of JP-A-55-167232) and comparison with the above method, the results shown in Table 3 below were obtained.

【table】

【table】

Claims (1)

[Claims] 1. General formula [In the formula, m represents an integer of 4 to 11] A cyclic ketone represented by the following is reacted with hydrogen peroxide in a saturated lower alcohol, and then the resulting cyclic ketone peroxide is expressed by the general formula [In the formula, R _f represents a fluoroalkyl group having 1 to 11 carbon atoms] or general formula [In the formula, R ₃ represents a methyl group or a trifluoromethyl group] A monomer represented by the following is reacted in the presence of a ferrous salt to form the general formula R ₁ -A-R ₂ () [In the formula, A is [Formula] [Formula] or -(CR _f = CH-) _o (R _f is a fluoroalkyl group having 1 to 11 carbon atoms,
R ₃ is a methyl group or a trifluoromethyl group, n is an integer of 1 to 3), R ₁ and R ₂ are the same or different, and are a hydrogen atom,
Fluorine atom, R ₄ OOC—(CH ₂ —) _n (R ₄ is a lower alkyl group, m is an integer from 4 to 11), R _f CH=CH— or
CF ₃ CR ₃ =CH- (R _f and R ₃ are the same as above). ) However, R ₁ and R ₂ are not simultaneously a hydrogen atom, a fluorine atom, R _f CH=CH- or CF ₃ CR ₃ = CH-, and at least one of R ₁ and R ₂ is R ₄ OOC-(CH _2- )m
A method for producing a fluorine-containing carboxylic acid ester, characterized by obtaining an ester represented by