JPH0533936B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing hexafluoropropylene oxide oligomers, and in particular, to a method for producing hexafluoropropylene oxide oligomers that allows easy control of the degree of polymerization of the oligomers produced and provides high yields. [Prior art] Hexafluoropropylene oxide (hereinafter referred to as "HFPO") oligomer is a surfactant,
It is known as a compound useful as an intermediate in the production of lubricants, heat transfer agents, and resins or elastomers with excellent properties. As for the production method of HFPO oligomer, HFPO
A method is known in which ion polymerization is carried out in an aprotic polar solvent using an alkali metal fluoride as a catalyst (JTHill, J.Macromol.Sci-Chem.
A-8499 (1974)). In particular, as a method for producing HFPO dimer or trimer oligomers, a method using a sulfonium halide or its complex as a catalyst in the presence of an organic polar solvent (Japanese Unexamined Patent Publication No. 118719/1982) , when using a catalyst in the presence of an organic diluent, alkylene glycol or polyalkylene glycol is used as part of the organic diluent (Japanese Patent Application Laid-Open No. 55-51032), and in the presence of a crown ether, a polar solvent is used. A method using an alkali metal fluoride as a catalyst in JP-A-57-64641
Publication No.) is known. [Problems to be solved by the invention] However, according to the method described in J. Macromol. A mixture of oligomers widely distributed from 2 to about 10 is obtained. Furthermore, in the methods described in some of the above-mentioned published patent publications, the oligomers obtained are exclusively 2
It has the disadvantage that it is difficult to produce oligomers, trimers, tetramers or higher oligomers, and the yield is relatively low. Therefore, an object of the present invention is to provide a method for producing HFPO oligomers in which the degree of polymerization of the produced oligomers can be easily controlled and the yield is extremely high. [Means for Solving the Problems] The present invention provides a method for producing HFPO oligomers, which involves polymerizing hexafluoropropylene oxide (HFPO) in an aprotic organic polar solvent using a catalyst. The present invention provides a method characterized in that the polymerization is carried out in the presence of at least one selected from monohydroxy compounds, ammonia, and amines or amine derivatives having active hydrogen. The HFPO oligomer obtained by the above method is
General formula: [In the formula, n is an integer from 0 to about 10.] The monohydroxy compound used in the present invention has the general formula () R ¹ −OH ... () [wherein R ¹ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an aryl group, or Representing an alkyl group having at least one etheric oxygen atom] Compounds represented by the following can be mentioned, and specifically, water;
Alkanols such as methanol, ethanol, propanol, cyclohexanol; phenol,
Examples include phenols such as cresol and naphthol; alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, and triethylene glycol monomethyl ether. As ammonia and amines or amine derivatives having active hydrogen, the general formula () [In the formula, R ² is a hydrogen atom, a hydroxyalkyl group, an aminoalkyl group, or a monoalkylaminoalkyl group; R ³ and R ⁴ may be the same or different, and R 2 is a hydrogen atom, a hydroxyalkyl group,
an aminoalkyl group, a monoalkylaminoalkyl group, a _C1 - _C20 alkyl group, a _C1 - _C20 cycloalkyl group, or a _C6 - _C10 aryl group, or ^R3 and ^R4 together Forming a _C2 - _C5 alkylene group] Specific examples other than ammonia include primary amines such as methylamine, ethylamine, cyclohexylamine, and aniline, dimethylamine, Examples include secondary amines such as diethylamine, diamines such as ethylenediamine, and alkanolamines such as ethanolamine, diethanolamine, and triethanolamine. These monohydroxy compounds, ammonia,
Alternatively, amines or amine derivatives having active hydrogen can be used alone or in combination of two or more, and the degree of polymerization of the produced oligomer can be controlled by adjusting the weight ratio with the catalyst described next. , the weight ratio of these compounds:catalyst is about 1:0.1
A range of from 1:1000 is preferred, particularly from about 1:1
1:200 is preferred. Conventionally, the catalyst used in the present invention is
As a polymerization catalyst for HFPO, for example, the above-mentioned J.
Macromol.Sci-Chem., JP-A-51-118719,
Examples include those known from Publications No. 55-51032, No. 57-64641, etc., and specifically, sodium fluoride, potassium fluoride, rubidium fluoride, cesium fluoride, acidic sodium fluoride (NaHF ₂ ), alkali metal fluorides such as acidic potassium fluoride (KHF ₂ ), tertiary amines such as trimethylamine, triethylamine, N,N-dimethylaniline, and pyridine, oxides of tertiary amines such as pyridine oxide, and aldonitron. , quaternary ammonium salts such as tetramethylammonium chloride, tetrabutylammonium iodide, tetraethylammonium fluoride, trimethylcetylammonium fluoride,
Examples include sulfonium salts such as triphenylmethylsulfonium bromide. The amount of the catalyst to be used is not a factor that affects the degree of polymerization of the oligomer, and is not particularly limited, and the weight ratio of catalyst to HFPO may be about 1:0.5 to 1:1000. The aprotic polar solvent used in the present invention includes acetonitrile, benzonitrile, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, N,N-dimethylformamide, dimethyl sulfoxide, hexamethylene phosphonamide, tetrahydrofuran, Dioxane etc. are exemplified. The reaction temperature in the present invention is desirably changed appropriately within the range of -80°C to +50°C depending on the catalyst used. For example, when water is used as the monohydroxy compound and CsF is used as the catalyst, about -40°C
It is in the range of ~+30℃. Furthermore, the polymerization reaction is preferably carried out in a sufficiently dry inert gas such as nitrogen, helium, neon, argon, etc. The pressure at that time is not particularly limited, and the reaction is usually carried out under self-generated pressure. Lower or higher pressures may be used if necessary. [Example] Example 1 In a flask 1 equipped with a magnetic stirrer, a thermometer, a gas inlet tube, and a condenser that can be cooled with dry ice and saturated with dry nitrogen, 2.74 g of sufficiently dried cesium fluoride and water were placed. 0.162g and tetraethylene glycol dimethyl ether 8.00
After introducing 300 g of HFPO in gaseous form into the suspension, the mixture was stirred at -20°C for 24 hours to react. Thereafter, the produced oligomer (carboxylic acid fluoride) was stabilized by methyl esterification using methanol, and then the yield of each oligomer was determined by gas chromatography. The results are shown in Table 1. Examples 2 to 6 HFPO oligomers were synthesized in the same manner as in Example 1 except that the amount of water charged was changed as shown in Table 1, and the yield of each oligomer was measured after methyl esterification. The results are shown in Table 1.

[Table] Comparative Examples 1 to 4 Polyethylene glycol 400 (PEG
-400) or crown ether (18-crown-
6) was used in the amount shown in Table 2, HFPO was polymerized in the same manner as in Example 1, and the yield of each oligomer was measured after methyl esterification. The results are shown in Table 2.

[Table] Examples 7 to 14 Polymerization of HFPO was carried out in the same manner as in Example 1 except that various monohydroxy compounds, amines, or amine derivatives shown in Table 3 were used in the amounts shown in the table instead of water. The yield of each oligomer was measured after methyl esterification.

〔Effect of the invention〕

The method for producing hexafluoropropylene oxide oligomers of the present invention can produce oligomers with a high yield of about 90% or more, and the ratio of the monohydroxy compound, ammonia, amine or amine derivative used and the catalyst By adjusting , the degree of polymerization of the oligomer can be controlled from 2 to about 10, and an oligomer having a desired degree of polymerization can be easily obtained.

Claims (1)

[Claims] 1. In a method for producing a hexafluoropropylene oxide oligomer in which hexafluoropropylene oxide is polymerized in an aprotic organic polar solvent in the presence of a catalyst, the polymerization is performed using a monohydroxy compound, ammonia, and an amine or amine derivative having active hydrogen. The method described above is carried out in the presence of at least one selected from the following.