Bayer Aktiengesellschaft

Michael Immenkeppel

Hans-Dieter Block

Roland Kleinstuck

Peter Schmidt

Hermann Sicius

Herbert Odenbach

Cornelia Lensch

The present invention relates to a process for eliminating 1-phosphono-1-carboxycyclopentan-3-one (ketone) from, or reducing its content in, an aqueous solution of 2-phosphonobutane-1,2,4-tricarboxylic acid, characterized in that the solution is adjusted to a pH value of &gt; 6 using an aqueous inorganic base, particularly sodium hydroxide, and aqueous bleaching liquor is subsequently added in a molar ratio of NaOCl to ketone of &gt;5:1.

Process for eliminating 1-carboxy-1-phosphonocyclopentan-3-one from, or

This invention relates to an improved process for the continuous production of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) and alkali metal salts thereof, in which dialkylphosphite, and ethene-1,2-dicarboxylic acid dialkyl ester, are reacted in the presence of a basic catalyst to form phosphonosuccinic acid tetraalkyl ester, the ester thus obtained is directly reacted with alkyl-acrylate, in the presence of an alkaline catalyst and the reaction product thus obtained is directly hydrolyzed to PBTC or alkali metal salts thereof.

Process for the continuous production of

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Bonn, Germany

Michael Immenkeppel