Hoechst Aktiengesellschaft

Rudolf Heumuller

Werner Groh

Gerhard Wieners

Peter Herbrechtsmeier

Gunter Siegemund

Steffen Dapperheld

Jochen Coutandin

Jurgen Theis

Roland Stern

Manfred Wildt

Gerald Schutze

Manfred Fleissner

Esters of .alpha.-fluoroacrylic acid are accessible by hydrolysis of an .alpha.-hydroxymethyl-.alpha.-fluoromalonic acid ester, decarboxylation and dehydration of the hydrolysis product and subsequent esterification of the resulting .alpha.-fluoroacrylic acid with an alcohol. The esters are polymerizable and are suitable for use as a starting material for preparing fluoropolymers which in turn are usable as materials for manufacturing transparent articles. The polymers are high-molecular and non-crystalline and have softening temperatures of above 100.degree. C.

.alpha.-fluoroacrylic acid esters and polymers thereof

A thermoplastic molding compound consisting of units of 2,3-difluoroacrylic acid esters or their deuterated derivatives, or containing units of these esters, is distinguished by a high glass transition temperature and a high transparency. It is therefore suitable for the manufacture of beam waveguides for long transmission distances and high continuous use temperatures.

Transplant thermoplastic molding compound made of 2,3-difluoroacrylic

Certain esters of .alpha.-fluoroacrylic acid are accessible by hydrolyzing .alpha.-hydroxymethyl .alpha.-fluoromalonic acid esters and subsequently decarboxylating the hydrolysis product. The phenyl .alpha.-fluoroacrylates which are substituted on the phenyl radical can be prepared by hydroxymethylating dimethyl .alpha.-fluoromalonate, decarboxylating and dehydrating the resuiting dimethyl .alpha.-hydroxymethyl-.alpha.-fluoromalonate and esterifying the resuiting .alpha.-fluoroacrylic acid with substituted phenols. The substituted phenyl .alpha.-fluoroacrylates are colorless liquids or colorless solids which can be polymerized. They are suitable for use as a starting material for the preparation of fluorine polymers.

Substituted phenyl .alpha.-fluoroacrylates

Transparent thermoplastic molding composition of a polymer containing

Transparent thermoplastic molding composition, process for its

Transparent thermoplastic molding compound made of 2,3-difluoroacrylic

Optical waveguides of very good heat resistance and good light conductivity are composed of polymers which are derived from halogenated phenyl acrylates or phenyl methacrylates.

Core/shell optical waveguides with cores comprising halogenated phenyl

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

A transparent material of very good heat resistance and very good light conductivity is essentially composed of a polymer derived mainly from bromophenyl acrylates or bromophenyl methacrylates.

Transparent polymer material

A process for the preparation of fluoromalonic acid and derivatives thereof having the formula ##STR1## wherein R.sup.2 and R.sup.3 are equal or different and represent hydroxyl, the group OX, wherein X represents an alkali metal, alkaline earth metal or NH.sub.4.sup.+ ion or a C.sub.1 -C.sub.12 -alkyl group, or represent the group NR.sup.4 R.sup.5, wherein R.sup.4 and R.sup.5 are equal or different and are hydrogen or a hydrocarbon group of 1 to 12 carbon atoms, which comprises subjecting a compound of the formula ##STR2## wherein R.sup.1 is halogen of an atomic weight in the range from 35 to 127 and R.sup.2 and R.sup.3 have the meaning indicated above, to an electrolysis in an electrolyte liquid consisting of water, an organic solvent or a mixture thereof, at a temperature in the range of from - 20.degree. C. to the boiling temperature of the electrolyte, at a current density in the range of from 1 to 600 mA/cm.sup.2 at a cathode consisting of lead, cadmium, zinc, copper, tin, zirconium, mercury, alloys of at least 2 of these metals or of carbon.

Process for the preparation of fluoromalonic acid and its derivatives

Optical waveguides of plastic usually consist of a core and a jacket, the core material having a higher refractive index than the jacket material. A suitable core material is a fluorine-free polymer and a suitable jacket material is a fluorine-containing polymer, which can also contain deuterium. The optical waveguides can be produced by passing a polymer rod through a solution of the jacket polymer and then removing the solvent. The optical waveguides are particularly suitable for the transmission of data with the aid of light waves with a wavelength of 500 to 750 nm.

Optical waveguide with an essentially fluorine-free polymer core and a

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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Rodgau, Germany

Rudolf Heumuller