Hoechst Aktiengesellschaft

Solvay (societe Anonyme)

Solvay

Frank Ebmeyer

Gunter Siegemund

Tobias Metzenthin

Wolfgang Appel

Detlef Kampmann

Thomas Gries

Wolfgang Wanzke

Rudolf Rossmeissl

Harald Haberlein, Deceased

Ulf Otto Paulus-Von Russdorf

Ralf Finzel

Holger Mohn

By Mark Haberlein, Heir

By Jorg Haberlein, Heir

Klaus-Dieter Ginzel

By Hans Haberlein, Heir

The present invention relates to a process for the preparation of a particularly pure monochloroacetic acid, in which, in a first step, a hydrogenation of a mixture of mono- and dichloroacetic acid is carried out to a residual content of dichloroacetic acid of 400 to 600 ppm and, in a second step, this mixture is subjected to melt crystallization. The hydrogenation is carried out with a heterogeneous catalyst which comprises 0.1-5.0% by weight of palladium and in which active charcoal or silicon dioxide is used as the support.

Process for the preparation of a particularly pure monochloroacetic

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

The present invention relates to a process for preparing a particularly pure glycolic acid by saponification with chloroacetic acid with an excess of alkali metal hydroxide, with the resulting alkali metal chloride being filtered off, and the 20 to 70% strength by weight glycolic acid solution being subsequently subjected to an electrodialysis at 20.degree. to 40.degree. C. and a cell voltage of 0.5 to 2.5 V per cell pair. The process of the invention permits optimum removal of sodium chloride and chloroacetic acid as necessary for preparing a particularly pure glycolic acid. Other organic acids, nitrogen compounds, aldehydes and salts are not produced in this process and thus do not affect the product quality.

Process for preparing a particularly pure glycolic acid

The invention relates to the preparation of trifluoroacetyl fluoride by reacting trichloroacetyl chloride with anhydrous hydrogen fluoride in the gaseous phase on a catalyst which is obtainable by reacting a water-soluble chromium (III) salt with magnesium hydroxide or magnesium oxide in the presence of water, converting the reaction mixture into a paste, drying the paste and treating it with hydrogen fluoride.

Process for preparing trifluoroacetyl fluoride

The invention relates to a process for the preparation of trichloroacetyl chloride by reaction of acetyl chloride or acetaldehyde or chlorinated derivatives thereof with chlorine in the presence of active charcoal as the catalyst.

Process for the preparation of trichloroacetyl chloride

Process for preparing trifluoroethyl sulfur compounds from thiolates and 1-chloro-2,2,2-trifluoroethane. The invention relates to the preparation of trifluoroethyl sulfur compounds of the formula RSCH.sub.2 CF.sub.3 by reacting 1-chloro-2,2,2-trifluoroethane CH.sub.2 Cl--CF.sub.3 in a polar aprotic solvent with salts of thiols of the formula RSH, where R can be an alkyl or aryl radical or a heterocyclic radical.

Process for preparing trifluoroethyl sulfur compounds from thiolates and

The invention relates to a process for the recovery of perfluoroethercarboxylic acids from the crude product of the electrochemical conversion of these acids or of one of their soluble salts to perfluorinated ethers, in which the perfluoroethercarboxylic acids and their esters contained in the crude product are separated off with the aid of a solid basic alkali metal salt or its solution and converted, by reaction of the resulting salts with a strong acid, to the corresponding perfluoroethercarboxylic acids.

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Augsburg, Germany

Frank Ebmeyer