Societe Elf Atochem S.a.

Atochem

Joseph Nowocien

Yves Correia

Alexandre Salerno

Dominique Jourdain

The invention relates to a catalyst comprising a rare metal of Group VIII of the Periodic Table of Elements which has been deposited on an inert support and which has been used to dehalogenate .alpha.-halogenated carboxylic acids in the presence of hydrogen, and a rare metal of Group VIII of the Periodic Table of Elements which has been deposited on an inert support and which is such that the granulometry of b) is very much lower than that of a) to form a homogeneous mixture as a result of the action of currents of .alpha.-halogenated carboxylic acid and hydrogen wherein said invention is particularly useful for regenerating palladium catalyst used in the purification of crude monochloroacetic acid.

Catalyst for the dehalogenation of .alpha.-halogenated carboxylic acids

The invention relates to a catalyst comprising a rare metal of Group VIII of the Periodic Table of Elements which has been deposited on an inert support and which has been used to dehalogenate .alpha.-halogenated carboxylic acids in the presence of hydrogen, and a rare metal of Group VIII of the Periodic Table of Elements which has been deposited on an inert support and which is such that the granulometry of b) is very much lower than that of a) to form a homogeneous mixture as a result of the action of currents of .alpha.-halogenated carboxylic acid and hydrogen. It is particularly useful for regenerating palladium catalysts used in the purification of crude monochloroacetic acid.

The highly chlorinated methanes, e.g., carbon tetrachloride, are improvedly dechlorinated by reacting same with hydrogen in the presence of oxygen or an oxygen-containing gas, e.g., air, and a catalytically effective amount of a metal of the copper or precious metal Groups of the Periodic Table, typically in the form of a fixed or fluidized bed thereof, and advantageously in the gaseous phase.

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Chateau Arnoux, France

Joseph Nowocien