JPS5942676B2 - Perfluoroalkoxypropionic acid fluoride having the composition C↓9F↓1↓6O↓4 - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION '-Fluorinated alkene epoxides, such as tetrafluoroethylene epoxide or hexafluoropropene epoxide, may be prepared from alkali fluoride, quaternary ammonium fluoride, silver fluoride or activated carbon. Addition to the perfluorinated carboxylic acid fluoride in the presence of a catalyst forms a poly'-fluoroalkoxycarboxylic acid fluoride, and the compound formed is a starting material for the production of high efficiency lubricants. Important as a raw material.

This lubricant is obtained by hydrolysis of a carboxylic acid fluoride to the corresponding acid followed by fluorination decarboxylation to form a saturated ether with one less carbon atom. It is very chemically and thermally stable and can therefore withstand very high stresses. Of course, the reactions described always give mixtures of products with very different molecular weights. Pelkey Patent No. 751076
According to this invention, the use of silver nitrate as a catalyst allows selective dimerization of hexafluofpropene epoxide to form '-fluoro-alpha-propoxypropionic acid fluoride.

Thanks to the present invention, it is now possible to obtain a new perfluoroalkoxypropionic acid fluoride having the composition C_9F,604, and at the same time difluorophosfluoran is obtained in an almost quantitative yield.

The present invention provides hexafluoroperopene epoxide of the following formula C_F3-OF-C_F2, / (I) with the following general formula R
, -P-R3(■) [In the formula, R4, R2 and R3 may be the same or different and represent a di(C_1-R4) alkylamino group]
C_9F16 produced by reacting with a phosphorus compound represented by at a temperature of -50 to +10°C.
The present invention relates to '-fluoroalkoxypropionic acid fluoride having the composition O4.

Note that during this production, difluorophosfluorane is produced at the same time. Unless it is intended to produce a specific fluorophosfluoran, it is preferable to use phosphorus compounds of the formula whose alkyl groups are identical and have 1 or 2 carbon atoms. This is especially convenient.

In particular, phosphoric acid trisdimethylamide can be used. Yields are somewhat lower when using phosphoric acid trisdialkylamides containing 2 to 4 carbon atoms in each alkyl group. In the preparation of the above compounds, a phosphorus compound of the formula is generally charged in advance, and hexafluoropropene epoxide is introduced therein at the desired reaction temperature. However, it is also possible to charge hexafluoropropene epoxide in advance and introduce the phosphorus compound therein. Hexafluoropropene epoxide is used in pure form.

However, since hexafluoropropene is inert under the conditions of the process according to the invention, the proportion of the mixture of hexafluoropropene and hexafluoropropene epoxide obtained in the preparation of hexafluoropropene epoxide is You can also use quantity. Generally, 3 moles of hexafluoropropene epoxide of the formula are used per mole of the phosphorus compound of the formula.

In order to drive the reaction to completeness, it is advantageous to use a small excess of the epoxide, up to about 10%.
Unreacted epoxide can be easily recovered from the reaction mixture after the reaction is completed. The rate of addition of epoxide does not have to be too critical.

Depending on the case, the required amount can be added at once in liquid form. Depending on the addition rate and reaction depth, the reaction time may be 0.
．． 5 to 10 hours. The reaction temperature can range from -50°C to +1°C. However, because undesirable side reactions occur, the reaction intensity must not exceed +1'C. Further, it is better not to allow the reaction temperature to rise above 0°C. 40
It is advantageous to work at a vorticity of between -25 DEG C. and at this turbidity it is possible to operate without pressurization.

When the reaction temperature is -25°C or higher, it is appropriate to use a pressurized vessel, but such a depth is advantageous if the operation can be performed without using a specific solvent. . Particularly advantageous yields are obtained when the hexafluoropropene epoxide is fed at -10 DEG C. rapidly as it is consumed. The solvent or solvent mixture that can be used in the above process must be polar, aprotic and inert and liquid under the reaction conditions.

Examples of such solvents include nitrites such as acetonitrile, amides such as dimethylformamide or dimethylacetamide, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether (Diglyme), tetraethylene glycol dimethyl ether (Tetraglyme), etc., depending on the reaction vorticity. (
Suitable are ethers such as TetragIyme), diethyl ether, diisopropyl ether, tetrahydrofuran, dioxane, furthermore sulfolane, furthermore esters such as ethyl acetate or aromatic solvents such as nitrobenzene, fluorobenzene or chlorobenzene.
It is also possible to use suitably excess amounts of the reaction components, in particular the phosphorus compounds of the formula, or the reaction products or reaction mixtures as solvents as well. The amount of solvent used does not have to be too critical.

However, care must be taken to ensure that the reaction mixture can be sufficiently mixed under the applied reaction slurry and that the viscosity does not become too high. For example, 0.25 to 4 parts by volume of solvent are used per part by weight of the phosphorus compound of formula H. The above method can be performed discontinuously.

Of course, it can also be carried out continuously in a simple manner, in which case, for example, reaction components 1 and 1 are fed continuously, optionally with the addition of a solvent, into a reaction zone maintained at the reaction temperature. After the mixture remains in this reaction zone for a suitable time, it is removed from another location depending on the amount of reaction components added, and optionally introduced into a post-reactor to complete the reaction. Separation of the reaction products can be carried out by simple distillation. Since the perfluoroalkoxypropionic acid fluoride obtained by this process is poorly soluble in the simultaneously obtained difluorophosfluoran as well as in the solvents used, it generally precipitates out as a heavier phase and therefore does not form in the reaction mixture. It can be separated from To purify it, it is washed with a solvent such as acetonitrile and then distilled. The lighter difluorophosfluoran can similarly be purified by distillation, optionally after separation of the solvent. When treated with an excess of hexafluoropropene epoxide or with a mixture containing hexafluoropropene, it is recommended to warm the reaction mixture to 0 to 10'C before separating the reaction products. It's advantageous.

At this time, the dissolved amount of hexafluoropropene epoxide and, if necessary, hexafluoropropene evaporates in gaseous form,
These can be recovered. The obtained no-fluoroalkoxypropionic acid fluoride is C9Fl6O4
115 to 118 boil at C.

This product contains one more oxygen atom and two less fluorine atoms than the trimer of hexafluoropropene epoxide. This infrared absorption curve is shown in FIG. Its characteristics include 9.7 μ ['-Kin-Elmer (Per
Kin-Elmer) 457, NaCl gear pillar] exhibits strong IR absorption. Its structure corresponds to the following formula according to NMR spectral analysis, but it can of course exist in many conformational isomers and diastereoisomers.

From the phosphorus compound of the formula used in addition to the above '-fluoroalkoxypropionic acid fluoride, it is represented by the following general formula V-P (wherein R, , R2 and R3 have the meanings indicated for the compound of the formula). An equivalent amount of the corresponding difluorophosfluoran is obtained.

Although this difluorophosfluoran is a known compound, this compound could not be obtained conventionally without using extremely complicated methods. It is a '-fluoro-[alpha]-[3,6-dimethyl-1,4-dioxanyl-2-oxy]-propionic acid fluoride based on the structural formula of a novel perfluoroalkoxypropionic acid fluoride. The overall reaction can be represented by the following reaction formula: From the above propionic acid fluoride, an inert ethyl ether of the following formula is obtained by saponification and fluorination decarboxylation using known methods.

This /monofluoro-[3,6-dimethyl-1,4-dioxanyl-2-oxy]monoethane was heated to a temperature of 101 to 104°C.
It has a boiling point of The compounds are suitable, for example, as anti-friction agents, sealing fluids, insulation fluids or hydraulic fluids. The preparation of the compounds of the invention is illustrated by the following examples.

Example diethylene glycol dimethyl ether (diglyme) 3
00m1 and POCN(CH)2]33009(1
．． 67 mol) of hexafluoropropene epoxide and hexafluoropropene epoxide and hexafluoropropene epoxide at -40 to -30 °C under constant stirring in a high-necked Kolben equipped with a strong condenser, a stirrer, and a low eccentricity meter. A mixture consisting of fluoropropene (
Weight ratio 65:35) 1400f9 is introduced.

The amount of preparation is 201 per hour. Then, the mixture was stirred for an additional 5 hours at the above-mentioned temperature. The mixture is then gradually strained to 0° C. to drive off hexafluoropropene and excess epoxide, and the resulting two-phase mixture is separated by liquid separation loading. Lower phase (
871y) with 600 ml of acetonitrile to obtain the product mixture 7JMoV1. Distill this. First fraction:
52 DEG -115 DEG C.=579 IR spectrum: Absorption at 9.7 .mu. (Perkin-Elmer 457, NaCl Gear Pillar) The upper phase consists of a mixture of diglyme and difluoro-tris-dimethylaminofluorane.

This is worked up by distillation. Difluorotris-dimethylaminofluoran 2579 (89% of theoretical value)
) is obtained. Boiling point 22℃/0.4m7! LHg Similar results were obtained under the same conditions as above, except that diglyme was replaced with tetraglyme.

[Brief explanation of the drawing]

FIG. 1 shows an infrared absorption curve measured with a Perkin-Elmer 457 in a NaCl gear pillar of perfluoroalkoxypropionic acid fluoride prepared according to the present invention.

Claims (1)

[Claims] Perfluoro-α-[3,6-dimethyl-
1,4-Dioxanyl-3-oxy]-propionic acid fluoride.