Hoechst Aktiengesellschaft

Manfred Wildt

Steffen Dapperheld

Rudolf Heumuller

Werner Schwertfeger

Klaus Kuhlein

Hans Millauer

Thomas Karcher

Peter Brungs

The invention relates to 2-alkylmercapto-4-(trifluoromethyl)benzoic esters of the formula (II), in which R.sup.1 and R.sup.2 are, independently of each other, (C.sub.1 -C.sub.6) alkyl, and a process for their preparation, which comprises reacting 3,4-dichlorobenzotrifluoride electrochemically at an anode with CO.sub.2 to give 2-chloro-4-(trifluoromethyl)-benzoate, converting it into the corresponding benzoic ester of the formula (I), and then reacting it with an alkylmercaptide R.sup.2 S.sup.e. ##STR1##

2-alkylmercapto-4-(trifluoromethyl)benzoic esters and a process for

In the preparation processes known hitherto for haloacrylic acids and deuterated derivatives thereof, it is necessary to use chemicals, some of which are very toxic or very expensive. However, fluoroacrylic acids are successively prepared from halogenated fluoropropionic acids and derivatives thereof by electrochemical elimination of halogen atoms. For this purpose, the acids or derivatives thereof are electrolyzed in a water-containing solution at a temperature from -10.degree. C. to the boiling point of the electrolysis liquid.

Process for the preparation of fluorinated acrylic acids and derivatives

The invention relates to a process for preparing compounds of the formula

Process for preparing fluorinated vinyl ethers

The existing processes for the preparation of halogenoacrylic acids and deuterated derivatives thereof have to be carried out using chemicals which are in some cases very toxic or very expensive. Electrochemical reduction, however, makes it possible to eliminate one or more halogen atoms selectively from halogenoacrylic and halogenomethacrylic acids and derivatives thereof, and to replace these by hydrogen or deuterium atoms. This is effected by electrolyzing the acids or derivatives thereof in a solution containing water or deuterium oxide at a temperature from -10.degree. C. up to the boiling point of the electrolysis liquid.

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Brombachtal, Germany

Manfred Wildt