Abstract: A transparent thermoplastic molding compound consisting of 40 to 90% by weight of units derived from tetrafluoroethylene, and 60 to 10% by weight of units derived from compounds of formula I or II:CF.sub.2 .dbd.CF--O--(CF.sub.2 --CF(CF.sub.3)--O).sub.m --(CF.sub.2).sub.n --CF.sub.3 (I)CF.sub.2 .dbd.CF--O--(CF.sub.2 --CF(CF.sub.3)--O).sub.p --(CF.sub.2).sub.q --COO--R (II)is particularly suitable for manufacturing the sheath of beam waveguides whose core has a higher transparency than polymethyl methacrylate.

Abstract: 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.

Abstract: Process for the preparation of fluorinated carboxylic acid fluoridesFluorinated 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.

Abstract: Solutions of copolymers of the tetrafluoroethylene/ethylene typeCopolymer 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.