Hoechst Aktiengesellschaft

Hoechst Aktiengelselschaft

Peter Blickle

Klaus Hintzer

Werner Schwertfeger

Gernot Lohr

Peter Herbrechtsmeier

Heinz Strutz

Hans Millauer

Gerhard Wieners

Jochen Coutandin

Johannes Brandrup

Friedhelm Gundert

Dieter Ulmschneider

G/u/ Nter Siegemund

Transparent thermoplastic molding compound and use thereof

Fluorinated carboxylic acid fluorides of the formula I ##STR1## can be prepared from fluorinated vinyl ethers of the formula II ##STR2## by reacting the vinyl ethers with an oxygen-containing gas in the presence of a catalytic amount of a Lewis acid. Perfluorinated carboxylic acids and derivatives thereof can be prepared from the carboxylic acid fluorides by secondary reactions, for example hydrolysis, esterification or aminolysis.

Fluorinated carboxylic acid fluorides

Process for the preparation of fluorinated carboxylic acid fluorides Fluorinated carboxylic acid fluorides of the Formula I ##STR1## can be prepared from fluorinated vinyl ethers of the Formula II ##STR2## by heating the vinyl ethers to a temperature of 100.degree. to 350.degree. C. Perfluorinated carboxylic acids and derivatives thereof can be prepared from the carboxylic acid fluorides by secondary reactions, for example hydrolysis, esterification or aminolysis.

Process for the preparation of fluorinated carboxylic acid fluorides

Solutions of copolymers of the tetrafluoroethylene/ethylene type Copolymer solutions comprising tetrafluoroethylene, ethylene and, as appropriate, further .alpha.-olefinic monomers in low-molecular-weight polymers of chlorotrifluoroethylene are described. They can be used for coatings, impregnations, cast films and for the production of fibers and filaments by gel spinning.

Solutions of copolymers of the tetrafluoroethylene/ethylene type

A trifluoroacrylate has been prepared by reacting hexafluoropropene with halogen fluorosulfate (halogen X:Cl, Br or I), eliminating the fluorosulfate CF.sub.3 --CFX--CF.sub.2 --OSO.sub.2 F to give the acid fluoride CF.sub.3 --CFX--COF, esterifying the acid fluoride and dehalogenating the product using a metal component.

Process for the preparation of trifluoroacrylates

The invention relates to solutions of fluoropolymers which preferably contain carbonate groups, in solvents of the general formula (I) ##STR1## These solutions are suitable, in particular, for the production of membranes for liquid permeation processes, such as electrolysis.

Solutions of fluoropolymers, and their use

3-Hydroxy-3-methylglutaric acid is prepared by electrolysis of an aqueous alkaline solution of 3-methyl-1,3,5-pentanetriol using anodes coated with nickel oxide/hydroxide NiO(OH) and conventional cathodes, followed by acidification of the alkaline solution and conventional working up. The yields achieved by this are always between about 70 and 85% of theory.

Process for the preparation of 3-hydroxy-3-methylglutaric acid

Substantially non-crosslinked fluorocarbon polymers containing carboxyl groups are prepared starting from non-crosslinked and in some cases new, fluorocarbon polymers in which the linear macromolecules carry side chains containing the end group --CHFX (X is F or CF.sub.3). The starting polymers are first reacted with peroxodisulfuryl difluoride FSO.sub.2 O--OSO.sub.2 F to give the corresponding fluorosulfato derivatives containing the side chain end groups. ##STR1## In the event that X is F, these derivaties are then converted into the corresponding carboalkoxy derivatives by means of an alcohol, the fluorosulfato group being split off, and these carboalkoxy derivatives are then converted by saponification into the products containing the free carboxyl groups; the fluorosulfato derivatives can also be hydrolyzed with water, if appropriate in the presence of an inert solvent and/or bases, to give, without further treatment, the products containing the free carboxyl groups. The fluorosulfato derivatives in which X is CF.sub.3 in the side chain end groups are first decomposed in the presence of catalytic amounts of alkali metal fluorides and/or aprotic nitrogen bases to give the products containing the side chain end groups ##STR2## and the latter are then hydrolyzed to give the products containing the free carboxyl group. Virtually non-crosslinked fluorocarbon polymers containing carboxyl groups are of industrial importance in the form of cation exchanger membranes in electrolytic cells, particularly in chlor-alkali electrolysis.

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Taunus, Germany

Peter Blickle