PROCESS FOR THE PURIFICATION OF PHOSPHOROUS ACID

The purification of phosphorous acid which is formed in halogenations of hydrocarbon derivatives using phosphorus trihalides is carried out in the context of preparing phosphorous acid in a reaction zone by reacting a mixture of phosphorus trichloride and water which has been finely divided by means...

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Bibliographic Details
Main Authors HOFMANN, BERNHARD, SCHIMMEL, GUENTHER, GROSSE, JUERGEN
Format Patent
LanguageEnglish
German
Published 25.09.1991
Subjects
CHEMISTRY
COMPOUNDS THEREOF
INORGANIC CHEMISTRY
METALLURGY
NON-METALLIC ELEMENTS
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Summary:The purification of phosphorous acid which is formed in halogenations of hydrocarbon derivatives using phosphorus trihalides is carried out in the context of preparing phosphorous acid in a reaction zone by reacting a mixture of phosphorus trichloride and water which has been finely divided by means of steam at temperatures between 150 DEG and 200 DEG C. in the gas phase. In this process, the liquid reaction product drains into a concentrating evaporation zone which has a downstream first separation zone. Inert gas is introduced to the lower part of the first separation zone. A melt is withdrawn from the first separation zone into a crystallizing zone. The waste gases from the reaction zone are treated with a washing liquid in a second separation zone before being passed into the atmosphere. The washing liquid used is an aqueous solution of never-purified phosphorous acid, which can have been prepurified by hydrolysis and stripping.
Bibliography:Application Number: EP19880106102