Bayer Aktiengesellschaft

Lanxess Deutschland Gmbh

Horst Bertram

Paul Wagner

Hans-Dieter Block

Hans-Heinrich Moretto

Peter-Roger Nyssen

Roland Kleinstuck

Thomas Weiβ

Wolfgang Ohlendorf

Christoph Holzner

Gunther Stolp

The invention relates to a process for eliminating nitrogenous organic compounds from a salt-containing water which contains more than 0.5% by weight of salt in the form of CaClor NaCl, less than 200 ppm of dissolved carbonic acid or carbonates and more than 50 ppm of nitrogenous organic compounds, by treating the water by wet oxidation at a temperature of below 100&#xb0; C. with chlorine or a chlorine-containing oxidizing agent and feeding this, preferably after additional oxidation with a gaseous oxidizing agent and/or by adsorption with an adsorbent, to an electrolysis for producing chlorine and/or sodium hydroxide solution.

Process for eliminating nitrogenous organic compounds from salt-containing water

This invention relates to an improved process for the production of 2-phosphono-butane-1,2,4-tricarboxylic acid (PBTC) and the alkali metal salts thereof, in which process dialkyl phosphite, preferably dimethyl or diethyl phosphite, and ethene-1,2-dicarboxylic acid dialkyl ester, in particular the dimethyl or diethyl ester of maleic acid and/or fumaric acid, are initially reacted in the presence of a basic catalyst to yield a phosphonosuccinic acid tetraalkyl ester, the resultant ester is thereupon reacted without further working up with acrylic acid alkyl ester, preferably methyl or ethyl acrylate, in the presence of an alkaline catalyst and the reaction product obtained in this manner is saponified without further working up to yield PBTC or the alkali metal salts thereof. The product when mixed with bleaching lye exhibits reduced chlorine depletion.

Production of 2-phosphonobutane-1,2,4-tricarboxylic acid and the alkali

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Kö'ln, Germany

Horst Bertram