DE1076113B - Process for the preparation of 1, 1, 1-Trifluoraethylalkylaethern - Google Patents

Description

GERMAN

It is known to produce trifluoroethyl alkyl ether by the reaction of Williamson, with trifluoroethyl halides be reacted with sodium alcoholates. However, this procedure is very cumbersome, because of the low boiling points of the trifluoroethyl halides used for implementation Autoclaves must be used as reaction vessels, and high reaction temperatures are also required are and the achievable yields have proven to be inadequate.

It has now been found that trifluoroethylalkyl ethers of the general formula CF ₃ -CH ₂ -O-R, where R is a straight-chain or branched alkyl radical having 1 to 18, preferably 1 to 4 carbon atoms, a cycloalkyl radical or a 1,1,1-trifluoroethyl radical, without the use of excess pressure and even at the relatively low temperatures of about 30 to about 150 ° C in conventional stirred vessels by reacting sodium l ^ l-trifhioethylate with alkylarylsulfonic acid esters, arylsulfonic acid esters or dialkyl sulfates. The above-mentioned esters contain, according to the ethers desired as reaction products, saturated aliphatic alcohol components of 1 to 18, preferably 1 to 4, carbon atoms. Examples of sulfonic acid esters suitable for the alkylation of sodium l, l, l-trifluoroethylate are dimethyl sulfate, diethyl sulfate, alkyl benzenesulfonates and cyclohexyl p-toluenesulfonates. For example, when dimethyl sulfate acts on 1,1,1-trifluoroethyl alcohol in an aqueous alkaline solution at about 30 to 40 ° C., a smooth reaction gives 1,1,1-trifluoroethyl methyl ether in a yield of 80 to 90 percent by weight, based on on the converted 1,1,1-trinuoroethyl alcohol.

In the implementation of 1,1,1-trifluoroethyl alcohol with dialkyl sulfates, expediently in an aqueous alkaline solution, or with alkyl aryl sulfonic acid alkyl ester or alkyl arylsulfonates, expediently in an anhydrous medium, the corresponding is formed 1,1,1-Trifluoroäthylalkyläthers in direct Reaction, d. H. without the formation of an intermediate product. However, one can also proceed in such a way that one the aryl or alkylarylsulfonic acid-ljljl-trifluoroethylester during the reaction, for example by reacting sodium l, l, l-trifluoroethylate with Forms p-toluenesulfonic acid chloride, the p-toluenesulfonic acid trifluoro-1,1,1-ethyl ester formed as an intermediate in the second stage with more sodium l, l, l-trifluoroethylate to form the ^, ^, / ^ ', / T-Hexafluorodiethylether reacts. The above illustrated reaction with p-toluenesulfochloride can be carried out in an analogous manner with other alkylaryl or arylsulfonic acid chlorides.

Method of manufacture
of 1,1,1 -Trifluoroäthylalkyläthern

Applicant:

Farbwerke Hoechst Aktiengesellschaft

formerly Master Lucius & Brüning,

Frankfurt / M., Brüningstr. 45

Dr. Otto Scherer, Frankfurt / M.-Höchst,

and Dr. Helmut Hahn, Frankfurt / M.,

have been named as inventors

As already stated above, the reactions according to the present invention take place between about 30 and about 150 ° C. In numerous cases, the reactions of trifluoroethyl alcoholate with dialkyl sulfate can be carried out at about 30 to about SO ⁰ C in the course of about 2 to 4 hours in one A yield of 80 to 90 percent by weight, based on the converted 1,1,1-trifluoroethyl alcohol, accomplish.

The reaction of sodium l, l, l-trifluoroethylate with alkylaryl or arylsulfonic acid alkyl esters requires slightly higher temperatures, usually about 100 ° C, and a period of about 8 to 10 hours. Here, too, the yields are very high, namely about 80 percent by weight, based on the converted 1,1,1-trifluoroethyl alcohol.

Compared to the previously known Williamson method, the method of the present Invention through its short reaction times, its pressureless and at relatively low temperatures feasible procedure with simultaneous achievement of high yields an essential technical Progress.

That the process of the present invention must be regarded as surprising is evident, for example, from the fact that according to J. Am. Chem. Soc, 72 (1950), p. 4378, paragraph 2, the β, β, β, β ', β', β'-JIexa fluorodiethyl ether cannot be represented by the methods customary for ether production and also in the cited literature on p. 4379, left column, penultimate paragraph, it is stated that the 1,1,1-trifluoroethyl alcohol cannot be converted into the corresponding ether by reaction with p-toluenesulfochloride.

909757/496

The fluorine-containing prepared according to the invention; Ether can be used in the pharmacological sector.

example 1

12 g of sodium are dissolved in 135 g of trifluoroethyl alcohol. 145 g of trifluoroethyltoluenesulfonic acid ester are added to the warm solution and the resulting mixture is stirred for 10 hours at 100 ° C. A mixture of excess trifluoroethyl alcohol and hexafluorodiethyl ether is then distilled off from the reaction flask. The two components are separated by shaking out with water, the ether being obtained as the water-insoluble part and the excess alcohol as the water-soluble part.

The yield of hexafluorodiethyl ether, based on the converted trifluoroethyl alcohol, is 85%. The boiling point of the product is bp ₇₆₀ = 63.8 to 64 ° C.

Example 2

17 g of sodium are dissolved in 155 g of trifluoroethyl alcohol. 70 g of p-toluenesulfonyl chloride are added to this solution. After the mixture had been kept at 100 ° C. for 8 to 10 hours, the mixture was distilled off, giving a crude distillate which, after shaking with water, gave 42 g / ^, ^ 'X / f-hexafluorodiethyl ether with a boiling point of ₇₆₀ = 64 ° C .

Example 3

50 g of trifluoroethyl alcohol are added to 250 ecm of water containing 16.5 g of dissolved sodium hydroxide. 52 g of dimethyl sulfate are then added dropwise with stirring over the course of about 30 minutes, the temperature rising to 34.degree. The mixture is then refluxed at 40 ° C. for 1 hour and the desired trifluoroethyl methyl ether is obtained by distilling off from the reaction solution in a yield of 80 to 85%, based on the converted trifluoroethyl alcohol of boiling point Kp. ₇₆₀ = 31 to 32 ° C.

Example 4

100 g of 1,1,1-trifluoroethyl alcohol are added to a solution of 42 g of sodium hydroxide in 1 cm of water, and 155 g of diethyl sulfate are then added dropwise at 46 ° to 50 ° C. over the course of 1 hour. After 3 hours of post-heating at about 60 ° C., the ethereal layer is separated off, _{dried over CaCl 2} and then distilled. The 1,1,1-trifluoroethyl ethyl ether with a boiling point of boiling point ₇₆₀ = 50 ° C. is obtained in a yield of 85%, based on the amount of 1,1,1-trifluoroethyl alcohol converted.

Claims (4)

Patent claims: 1. A process for the preparation of 1,1,1-trifluoroethylalkyl _{ethers of the general formula CF 3} -CH ₂ -OR, in which R is an alkyl radical of 1 to 18 carbon atoms, preferably 1 to 4 carbon atoms, a cycloalkyl radical or a 1,1,1 -Trifluoroethyl radical means, characterized in that sodium l, l, l-trifluoroethylate is reacted with a dialkyl sulfate, an alkylaryl or aryl sulfonic acid or -1,1,1-trifluoroethyl ester at a temperature between about 30 and about 150.degree . 2. The method according to claim 1, characterized in that that the reaction with dialkyl sulfates in an aqueous alkaline or in anhydrous medium he follows. 3. The method according to claim 1 and 2, characterized in that the reaction with alkylaryl or arylsulfonic acid alkyl or -1,1,1-trifluoroethyl esters takes place in an anhydrous medium. 4. The method according to claim 1 to 3 for the preparation of ^, ^, / ί ', ^', - hexafluorodiethyl ether, characterized in that sodium 1,1,1-trifluoroethylate in an anhydrous medium with ρ - toluenesulfonic acid - β, β , β - trifluoroethyl ester converts. © 909 757/496 2.60