Hoechst Aktiengesellschaft

Walter Steppich

Bernhard Wojtech

Dieter Freudenberger

Knut Riedel

Rudolf Sartorius

The invention relates to a process for the extraction of carboxylic acids from aqueous solutions with a carboxylic acid content below 8% by weight. A mixture of an aliphatic amine with a total carbon number of at least 10 and a phenol or naphthol is used as extracting agent. The molar ratio of phenol:amine or alkylated phenol:amine or naphthol:amine is in the range from 0.1:1 to around 1.1:1.

Process for the extraction of carboxylic acids from dilute aqueous

Process for the manufacture of acetaldehyde by reaction of ethylene and oxygen in the presence of an aqueous solution of palladium and copper chloride, in which continuously part of the latter solution is regenerated by heating it outside of the reactor. The gaseous mixture leaving the reactor is treated (a) by cooling with recycling of the condensate formed to the reactor and completion of the water portion that has not condensed during cooling, by the addition of water to the reactor, (b) by washing of the cooled gas mixture with water whereby an aqueous acetaldehyde solution is obtained, (c) by extractive distillation of this solution using water as extraction agent. Next, pure acetaldehyde is obtained as an overhead product in a further distillation step. The water demand of step (b) and optionally additionally of steps (a) and/or (c) is satisfied with the waste water obtained in the bottoms of the last distillation step and the residual waste water in each case is discharged.

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Wiesbaden, Germany

Walter Steppich