Other

Dsm N.v.

Antonius J F Simons

Imre Toth

Onko Jan Gelling

Rudolf P M Guit

Simon Hans H Niemann

Louise A Groot Zevert

Process for purifying an aqueous caprolactam mixture by extracting the caprolactam with the aid of an organic caprolactam solvent that is not miscible with water in a benzene extraction, and releasing the caprolactam from the organic solvent by means of extraction with water, with the formation of an aqueous caprolactam solution, in a back extraction, with at least a separate pre-extraction taking place before the benzene extraction and/or the back extraction, in which, in a pre-extraction before the benzene extraction, an organic solvent that is not miscible with water is used for the extraction and, in a pre-extraction before back extraction, water is used for the extraction.

Process for purifying caprolactam

Process to separate linear 5-formylvaleric acid from a mixture of 5- and 3- and 4-formylvaleric acids, wherein the separation is performed by fractional extraction with two immiscible solvents of which one solvent is an aqueous solvent and the other solvent is an organic solvent, in which the organic solvent has a higher or lower affinity for 5-formylvaleric acid than its affinity for the 3-formylvaleric acids and for the 4-formylvaleric acid. Furthermore the invention relates to an improved process to prepare &isin;-caprolactam starting from a mixture of branched and linear formylvaleric acids or starting from pentenoic acid.

Process to prepare 5-formylvaleric acid

Growing community of inventors

Geleen, Netherlands

Antonius J F Simons