Hoechst Aktiengesellschaft

Solvay (societe Anonyme)

Wolfgang Wanzke

Gunter Siegemund

Martin Sicken

Thomas Muller

Frank Ebmeyer

Wilfried Schmieder

G&uuml;nter Siegemund

Ralf Finzel

The invention relates to a process for the preparation of 1,1,1,2-tetrafluoroethane from 1,1,1-trifluoro-2-chloroethane and hydrogen fluoride in the gas phase, in which a catalyst containing chromium and magnesium is used which is obtainable by precipitating chromium(III) hydroxide by reacting 1 mol of a water-soluble chromium(III) salt with at least 1.5 mol of magnesium hydroxide or magnesium oxide in the presence of water, the reaction mixture is made into a paste containing chromium hydroxide and a magnesium salt, and the paste is then dried and treated with hydrogen fluoride at temperatures of 20 to 500&deg; C.

Process for the preparation of 1,1,1,2-tetrafluoroethane

Process for regenerating a fluorination catalyst The invention relates to a process for regenerating a fluorination catalyst containing chromium and magnesium after use in a fluorination reaction, in which the used catalyst is treated with a mixture comprising at least 10 mol % of HF, from 30 to 90 mol % of O.sub.2 and from 0 to 60 mol % of inert gas.

Process for regenerating a fluorination catalyst

A flame-retardant plastic molding composition of improved stability comprises

Flame-retardant plastics molding composition of improved stability

The invention relates to a process for the preparation of 1,1,1-trifluoro-2-chloroethane from trichloroethene and hydrogen fluoride in the gas phase. In this process a catalyst containing chromium and magnesium is used, which catalyst is obtainable by precipitating chromium(III) hydroxide by reacting 1 mole of a water-soluble chromium(III) salt with at least 1.5 mol of magnesium hydroxide or magnesium oxide in the presence of water, converting the reaction mixture into a paste containing chromium hydroxide and a magnesium salt and then drying the paste and treating it at temperatures of 20.degree. to 500.degree. C. with hydrogen fluoride.

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Frankfurt am Main, Germany

Wolfgang Wanzke