DE1294954B - Process for the production of vinyl ethers of perhalogenated, tertiary alcohols - Google Patents

Description

1 2

It has been found that vinyl ether perhaloge- 'ethyl bromide, ethyl iodide or diethyl sulfate, and by nated tertiary alcohols of the general formula subsequent halogenation, preferably with ele-

: mentary chlorine or bromine, the thus obtained single

1 ^2- sided perhalogenated ether can be produced.

I 5 It is known that one unsaturated aliphatic

Ri - C - O - CH = CH ₂ compounds can be made by using halogen

I alkanes with inorganic or organic bases

R ₃ treated with elimination of hydrogen halide (cf.

Weygand, »Organic-Chemical Experimental

wherein R ₁ , R ₂ and R ₃ straight-chain or branched io art "[1964], p. 788). In contrast, perfluorocarbon residues or perfluorochlorocarbon; However, the production of vinyl ethers from α-halo radicals, in which the number of chlorine atoms no longer approximates considerable difficulties. It is achieved as about a quarter of the number of fluorine atoms either with alkali metal hydroxides or with aliphatic bears, meaning, is obtained when tertiary α-halogen amines are used. Somewhat satisfactory results eräthyläther of the general formula 15 is obtained only when using pyridine or di-

.-. methylaniline, although you have the desired

² 'vinyl ether is only obtained in moderate yield (cf.

Houben-Weyl, »Methods of the Organic

Ri - C - O - CH - CH ₃ Chemistry «, 6/3» Oxygen Compounds I «, page 102).

Il 20 With regard to the fact that the overpass

R ₃ X the «halo used in the present process

genäthyläther in the desired vinyl ether neither

where R ₁ , R ₂ and R _{3 have} the above meanings using pyridine or dimethyl and X is a chlorine or bromine atom, aniline succeeds, it had to be assumed that with alkali or alkaline earth metal hydroxides, carbonates, 35 hydrogen halide splitting off even more would not alcoholates or amides or quaternary ammolings if the alkali oxide, tetrahydrothiophene-l, l-dioxide, dimethylacetahydroxide or similar compounds described in the last-mentioned sodium compounds in the presence of dimethylsulf literature were ineffective for this amide or dimethylformamide treated. Purpose would use. With regard to the training

The radicals R ₁ , R ₂ and R ₃ in the aforementioned 30 statements in this reference were therefore very formulas can contain 1 to 8 carbon atoms. Surprisingly that the desired vinyl ethers are preferably obtained these radicals are perfluorinated carbon in good yields if the corresponding radicals with 1 to 4 carbon atoms are obtained. Examples of the α-halogenoethyl ether with the above geVerbindungen, which can be used as starting compounds in the case of the named basic compounds according to the invention in countermeasures for aprotic solvents or diluents, are the -chlorine or α-bromo derivatives of treated. Furthermore, it was very surprising that ethyl-perfluoro-tert-butyl-, ethyl-perfluoro-2,3-dime- also alkali or ethyl-butyl- (2) -, ethyl-perfluoro-2-methyl in the process according to the invention -butyl- (2) -, alkaline earth alcoholates can be used with very good success, ethyl-perfluoro-3-methyl-pentyl- (3) - and ethyl-per-. Based on the statements in fluoro-3-ethyl-pentyl (3) -ether. 40 "Chemical Reviews", 55 (1955), at p. 322, according to

In the process of the invention, as those in the treatment of α-monohaloalkyl basic active compound preferably sodium ethers with alkoxides the corresponding acetals in methylate and formed as a solvent, preferably diminutive reaction, was of course ananthylformamide used. take that also in the treatment of the procedural

The reaction can be carried out e.g. B. in the 45 according to used starting compounds with Alko manner take place that one to holaten the "-Halogenäthyläther not the vinyl compounds, but much the corresponding acetals can be obtained in the base initially introduced in the aprotic solvent admits. . would.

The molar ratio of base to starting compound The vinyl ethers obtainable according to the process are

Application should be in the range from 1 to 2: 1. The 50 new compounds that are used to produce new reaction temperatures are said to be in the range of 0 to like plastics. 100 ^° C., preferably from 10 to 50 ^° C., are and are. .

if necessary by adding or dissipating heat Example!

be regulated. The reaction time can vary from 2 In one with stirrer, thermometer and drip

extend to about 20 hours. The reaction mixture, 55 funnel-equipped reaction vessel will be 81g which may not be homogeneous, is expedient- (1.5 mol) powdered sodium methylate and 1000 ml moderately stirred. The work-up of the reaction dimethylformamide submitted. To do this, under Mixture can be separated by separating 443 g (1.0 mol) of a-bromoethyl-perfluoro-2,3-dis-boiled, liquid reaction product, given methyl-butyl (2) ether [obtainable by reacting if after previous addition of water, or by 60 perfluoro-2,3-dimethyl-butanol- (2) with diethyl sulfate in Distilling off the reaction product or driving off diethylene glycol dimethyl ether in the presence of done by means of steam. The potassium carbonate obtainable in this way and subsequent implementation of the Ethyl perfluoro-2,3-dimethyl-butyl- (2) -tion thus obtained can be obtained by drying and distillation getting cleaned. ether with bromine under UV radiation].

The method used according to Ausgangsver- 65 by cooling, a temperature of 10 to compounds may complied by reacting alkali or 2O ⁰ C. Then the reaction alkaline earth salts of perhalogenated tertiary alkali mixture is stirred for 19 hours at about 20 ° C, fetched with ethylating agents such as ethyl chloride, After filtering off undissolved salts

the filtrate, which consists of two phases, is separated in a separating funnel, the lower phase is extracted once with water and separated again. 315 g of crude vinyl perfluoro-2,3-dimethyl-butyl (2) ether are obtained, which corresponds to a yield of 87% of theory S. The purity of the crude product is after the removal of traces of water by means of some calcium chloride over 99.5 ° / _0th A completely pure product is obtained by fractional distillation (bp = 100 ^{° C.).}

Example 2

70 g (1.3 mol) of powdered sodium methylate and 1000 ml of dimethylformamide are placed in a reaction vessel equipped with a stirrer, thermometer and dropping funnel. To do this, 398 g of a-chloroethyl perfluoro-2,3-dimethylbutyl (2) ether [obtainable by chlorinating ethyl perfluoro-2,3-dimethyl-butyl (2) ether with elemental chlorine under irradiation with a UV lamp] added ao. A temperature of 8 to 10 ^° C. is maintained by cooling. Then the reaction mixture is stirred for 20 hours at 10 to 2O ⁰ C. Undissolved salts are filtered off from the reaction mixture, the filtrate, which consists of two phases as, is separated, the lower phase is extracted once with water and deposited again. 260 g of crude mixture are obtained, which consists of about 70% vinyl perfluoro-2,3-dimethyl-butyl (2) ether and about 30% a-chloroethyl-perfluoro-2,3-dimethyl-butyl (2) -ether exists. The yield is 62%, based on converted α-chloroethyl perfiuor ^ jS-dimethyl butyl (2) ether. The pure product with a boiling point of 100 ^° C. is obtained by fractional distillation.

Claims (1)

Claim: Process for the production of vinyl ethers perhalogenated tertiary alcohols of the general formula R « R ₁ -CO-CH = CH ₂
R3 wherein R ₁ , R ₂ and R _{3 are} straight-chain or branched perfluorocarbon atoms or perfluorochlorocarbon radicals in which the number of chlorine atoms is not more than about a quarter of the number of fluorine atoms, characterized in that tertiary α-haloethyl ethers of the general formula R * R ₁ -CO-CH-CH ₃ wherein R ₁ , R ₂ and R _{3 have} the above meanings and X is a chlorine or bromine atom, with alkali or alkaline earth metal hydroxides, carbonates, alcoholates or amides or quaternary ammonium compounds in the presence of dimethyl sulfoxide, tetrahydrothiophene-1,1- treated with dioxide, dimethylacetamide or dimethylformamide.