Hoechst Aktiengesellschaft

Alfred Hauser

Andreas Seidel

Klaus Gehrmann

Heinz Erpenbach

Winfried Lork

Peter Prinz

Erhard Jagers

Kurt Karrenbauer

A process for the removal of aldehydes and acetals from industrially prepared acetic acid, wherein the contaminated acetic acid is reacted in the presence of a Bronstedt acid and 0.05 to 1% by weight of water and, if required, of 3 to 10 equivalents, calculated on aldehyde and acetal, of a high boiling polyhydric alcohol, and isolating the purified acetic acid by fractional distillation.

Process for the removal of aldehydes and acetals from industrially

Waste acetic acid, which is contaminated by nitrogen compounds and also by hardly hydrolyzable halogen compounds, is purified by adding a complex-forming metal or one of the compounds thereof and a basic compound. The resultant mixture is kept at a temperature between 25.degree. and 118.degree. C. over a period of time of 1 to 6 hours. Finally, purified acetic acid is removed from the mixture by distilling.

Process for the purification of waste acetic acid

Acetic acid and acetic anhydride are produced continuously from acetaldehyde which is reacted by oxidizing it with gaseous oxygen in liquid phase in the presence of copper acylate and cobalt acylate as a catalyst and in the presence of an aliphatic carboxylic acid ester as a diluent. More specifically, the reaction is effected at temperatures of 62.degree. to 90.degree. C. over a period of less than 20 minutes with the use of the diluent and acetaldehyde in a quantitative ratio of 60:40 to 40:60; the resulting reaction products are delivered to a distilling zone in which the carboxylic acid ester and water are distilled off overhead and separated into two phases. Next, the organic phase is recycled with a reflux ratio of at least 1:1 to the distilling zone; base product accumulating in the distilling zone is delivered to an evaporating zone in which 2 to 12 parts by weight of an acetic acid/acetic anhydride-mixture as distillate are produced per part by weight of catalyst solution as base product.

Production of acetic anhydride and acetic acid from acetaldehyde

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Erftstadt, Germany

Alfred Hauser