JP4362908B2 - Production method of monoester from dicarboxylic acid fluoride - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a monoester from dicarboxylic acid fluoride. More specifically, the present invention relates to a method for producing a monoester monoacid fluoride of dicarboxylic acid useful as a raw material for synthesizing perfluorovinyl ether from dicarboxylic acid fluoride.
[0002]
[Prior art]
Perfluorovinyl ether is a useful monomer used for fluorine-containing elastomers and the like, and its synthesis is carried out by converting the acid fluoride group of dicarboxylic monoester monoacid fluoride to a carboxylate and then carrying out a thermal decomposition reaction. (Japanese Patent Publication No. 53-33572-3).
FOCCF (CF ₃ ) O (CF ₂ CFXO) p (CF ₂ ) qCOOR
↓
MOOCCF (CF ₃ ) O (CF ₂ CFXO) p (CF ₂ ) qCOOR
↓
CF ₂ = CFO (CF ₂ CFXO) p (CF ₂ ) qCOOR
[0003]
The monoester monoacid fluoride of dicarboxylic acid used here is generally obtained by reacting dicarboxylic acid fluoride with an equimolar amount of alcohol and esterifying one acid fluoride group. In this case, reaction of the alcohol used The selectivity increases when the molar ratio is small, but there is a problem that a large amount of unreacted dicarboxylic acid fluoride remains and the conversion does not increase. On the other hand, when the reaction molar ratio of alcohol is increased, the conversion rate is increased, but the amount of diester produced is increased and the selectivity is decreased.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for increasing the conversion rate and the selectivity in producing a monoester monoacid fluoride of dicarboxylic acid from dicarboxylic acid fluoride, thereby improving the yield of the target product. .
[0005]
[Means for Solving the Problems]
The object of the present invention is to provide a general formula
FOCCF (CF ₃ ) OCF ₂ (A) p (CF ₂ ) qCOF
(Wherein A is a bifunctional perfluorinated group having 1 to 10 carbon atoms, p is 0 or 1, and q is 0 or an integer of 1 to 10). This is achieved by a method of producing a monoester monoacid fluoride of a dicarboxylic acid by reacting with an alcohol having 3 or more carbon atoms and esterifying the CF ₂ COF group side .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The asymmetric dicarboxylic acid fluoride represented by the above general formula is obtained by reacting a dicarboxylic acid fluoride represented by the general formula FOC (A) p (CF ₂ ) qCOF with hexafluoropropylene oxide (US Pat. No. 3,114,778) or JP-B-57-61339 discloses that it can be obtained by a method of reacting a fluorolactone with hexafluoropropylene oxide (Japanese Patent Laid-Open No. 53-3017).
[0007]
Here, A is a branched or unbranched bifunctional perfluorinated group, which may contain one or more ether linkages, and may be a group represented by the following general formula, for example.
-[CF (CF ₃ ) OCF ₂ ] m (Rf) n-
Rf: linear or branched perfluoroalkylene group having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms
m: 0, 1 or 2
n: 0 or 1
[0008]
Examples of such dicarboxylic acid fluorides include the following compounds.
FOCCF (CF ₃ ) OCF ₂ COF
FOCCF (CF ₃ ) O (CF ₂ ) ₂ COF
FOCCF (CF ₃ ) O (CF ₂ ) ₃ COF
FOCCF (CF ₃ ) O (CF ₂ ) ₄ COF
FOCCF (CF ₃ ) O (CF ₂ ) ₅ COF
FOCCF (CF ₃ ) OCF ₂ CF (CF ₃ ) OCF ₂ COF
FOCCF (CF ₃ ) OCF ₂ CF (CF ₃ ) O (CF ₂ ) ₂ COF
FOCCF (CF ₃ ) OCF ₂ CF (CF ₃ ) O (CF ₂ ) ₃ COF
FOCCF (CF ₃ ) OCF ₂ CF (CF ₃ ) O (CF ₂ ) ₄ COF
FOCCF (CF ₃ ) OCF ₂ CF (CF ₃ ) O (CF ₂ ) ₅ COF
[0009]
Examples of alcohols that react with these dicarboxylic acid fluorides include alcohols having 3 or more carbon atoms such as propanol, isopropanol, n-butanol, isobutanol (2-butanol), 2-methyl-1-propanol, 4-heptanol, 2, 2-dimethyl-1-propanol, 2,4-dimethyl-3-pentanol and the like are used, and alcohol having a branching group is preferably used.
[0010]
The reaction between the two is carried out at a reaction temperature of about -60 to 60 ° C. using 0.7 to 2 mol, preferably about 1 to 1.5 mol, of alcohol with respect to 1 mol of dicarboxylic acid fluoride. The selectivity is improved when the reaction temperature is lower, but the reaction is preferably carried out at about -40 to 20 ° C. in view of the capacity and economics of the cooling device.
[0011]
This reaction can be carried out in the presence or absence of a solvent. When a solvent is used, any one can be used as long as the reaction is not inhibited, but diglyme used also in the synthesis step of dicarboxylic acid fluoride. Tetraglyme and the like are preferably used. Incidentally, hydrogen fluoride produced as a by-product of the condensation reaction is adsorbed by an alkali metal fluoride such as sodium fluoride coexisting in the reaction system, whereby corrosion of the reactor can be suppressed.
[0012]
【The invention's effect】
A copolymer obtained by copolymerizing perfluorovinyl ether is effectively used as a functional fluorine-containing polymer in applications such as water and oil repellents, but it is an intermediate for synthesizing perfluorovinyl ether as a component of such a copolymer. Monocarboxylic acid monoester fluoride FOCCF (CF ₃ ) OCF ₂ (A) p (CF ₂ ) qCOOR of dicarboxylic acid having a perfluoroether bond as an ester, in the present invention, an alcohol having 3 or more carbon atoms is selected as an esterifying agent By using it, it can manufacture with a conversion rate and a favorable selectivity.
[0013]
【Example】
Next, the present invention will be described with reference to examples.
[0014]
Reference Example 327 g (1.1 mol) of perfluoroadipic acid fluoride, 15.2 g (0.1 mol) of cesium fluoride and 300 ml of diglyme were reacted with 199.2 g (1.2 mol) of hexafluoropropene oxide at 0 to 5 ° C. Dicarboxylic acid fluoride FOCCF (CF ₃ ) O (CF ₂ ) ₅ COF was obtained by distillation.
[0015]
Example 1
In a glass reaction vessel with a capacity of 500 ml, charge 300 g (0.65 mol) of FOCCF (CF ₃ ) O (CF ₂ ) ₅ COF and 33 g of sodium fluoride and stir while maintaining the internal temperature at -30 to -20 ° C. Then, 42.9 g (0.72 mol) of propanol was added dropwise over 2 hours. After completion of the dropwise addition, sodium fluoride was filtered off to obtain 287 g of a mixture of raw material 15.8%, monoester 48.5% and diester 35.7% by gas chromatography composition. The reaction conversion was 84.2%, the monoester selectivity was 57.6%, and the yield was 42.8%.
[0016]
Example 2
In Example 1, the same amount of isopropanol was used instead of propanol to obtain 285 g of a mixture of raw material 11.4%, monoester 59.1% and diester 25.6%. The conversion of the reaction was 88.6%, the monoester selectivity was 69.8%, and the yield was 51.8%.
[0017]
Example 3
In Example 1, instead of propanol, 63.3 g (0.72 mol) of 2,2-dimethyl-1-propanol was dissolved in 30 g of tetraglyme, and a mixture of raw material 6.8%, monoester 74.0% and diester 17.0% 328 g was obtained. The conversion of the reaction was 93.2%, the monoester selectivity was 81.3%, and the yield was 64.3%.
[0018]
Example 4
In Example 1, 234 g (0.65 mol) of FOCCF (CF ₃ ) O (CF ₂ ) ₃ COF was used as the dicarboxylic acid fluoride, and 83.5 g (0.72 mol) of 2,4-dimethyl-3-pentanol was used instead of propanol. Was used to obtain 256 g of a mixture of raw material 5.8%, monoester 78.4% and diester 15.8%. The conversion of the reaction was 94.2%, the monoester selectivity was 83.2%, and the yield was 67.7%.
[0019]
Example 5
In Example 1, FOCCF (CF ₃ ) O (CF ₂ ) ₂ COF 202 g (0.65 mol) was used as the dicarboxylic acid fluoride, and 83.5 g (0.72 mol) of 2,4-dimethyl-3-pentanol was used instead of propanol. Was used to obtain 220 g of a mixture of raw material 6.7%, monoester 76.6% and diester 16.7%. The reaction conversion was 93.3%, the monoester selectivity was 82.1%, and the yield was 63.9%.
[0020]
Comparative Example In Example 1, 22.9 g (0.72 mol) of methanol was used instead of propanol to obtain 262 g of a mixture of raw material 19.0%, monoester 42.9% and diester 38.1%. The conversion of the reaction was 81.0%, the monoester selectivity was 53.0%, and the yield was 36.6%.

Claims (3)

General formula
FOCCF (CF ₃ ) OCF ₂ (A) p (CF ₂ ) qCOF
(Wherein A is a bifunctional perfluorinated group having 1 to 10 carbon atoms, p is 0 or 1, and q is 0 or an integer of 1 to 10). Is reacted with an alcohol having 3 or more carbon atoms to esterify the CF ₂ COF group, and a method for producing a monoester monoacid fluoride of a dicarboxylic acid. The A group in the general formula representing the asymmetric dicarboxylic acid fluoride is represented by the general formula
-[CF (CF ₃ ) OCF ₂ ] m (Rf) n-
(Wherein Rf is a perfluoroalkylene group having 1 to 10 carbon atoms, m is 0, 1 or 2, and n is 0 or 1). The method for producing a monoester monofluoride of dicarboxylic acid according to claim 1, wherein The method for producing a monoester monoacid fluoride of a dicarboxylic acid according to claim 1 or 2, wherein the alcohol having 3 or more carbon atoms is an alcohol having a branched group.