Other

Dsm N.v.

Rudolf P M Guit

Frank P W Agterberg

Wim Buijs

Nicolaas F Haasen

Imre Toth

Onko Jan Gelling

Samuel L Lane

Yvonne H Frentzen

Henricus F W Wolters

Antonius J F Simons

Simon Hans H Niemann

Matthias R J Offermanns

A process for the preparation of &egr;-caprolactam starting from 6-aminocaproic acid, 6-aminocaproamide, 6-aminocaproic ester, 6-aminocapronitrile, oligomers or polymers of these compounds or mixtures comprising at least two of these compounds, which process is performed in the presence of N-(5-carboxypentyl)-&egr;-caprolactam and/or derivative thereof in an amount of less than 50 wt. % and more than 0.1 wt. % (based on the total reaction mixture).

Process for the preparation of &egr;-caprolactam

Process for the preparation of &egr;-caprolactam comprising treating 6-aminocaproic acid 6-aminocaproate ester, 6-aminocaproamide, oligomers or polymers of these compounds or mixtures comprising at least two of these compounds in a cyclisation reactor in the presence of superheated steam in which a gaseous product stream comprising &egr;-caprolactam, lights and heavies is obtained, wherein the product stream, after condensation and at least partial removal of water and lights, is split into a &egr;-caprolactam stream and a heavies stream containing heavies and &egr;-caprolactam and the heavies stream is recycled to a cyclisation reactor.

Process to prepare &egr;-caprolactam starting from a starting mixture containing a 6-aminocaproate ester, in which in a first step (1) the 6-aminocaproate ester is converted into 6-aminocaproic acid and 6-aminocaproamide by reaction with water in the presence of ammonia at a temperature of between 50 and 250&deg; C., with a separate or simultaneous removal of alcohol(s), and in a subsequent step (2) the 6-aminocaproic acid and 6-aminocaproamide are cyclizised at an elevated temperature, wherein in step (1) the 6-aminocaproate ester is converted into 6-aminocaproic acid and 6-aminocaproamide in the presence of an amount higher than 2 wt. % and less than or equal to 25 wt. % NH,(relative to the total amount of organic compounds, water and ammonia present in step (1)).

The invention relates to a process for the purification of crude &egr;-caprolactam, wherein crude &egr;-caprolactam prepared by cyclization of alkyl 6-aminocaproate, 6-aminocapronitrile, 6-aminocaproic acid, 6-aminocaproic amide and/or oligomers thereof, is subjected to a crystallization process.

Process for the continuous purification of crude &egr;-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

Process to separate &egr;-caprolactam from 6-aminocaproamide and 6-aminocaproamide oligomers, wherein &egr;-caprolactam, 6-aminocaproamide and 6 aminocaproamide oligomers are present in a first aqueous starting mixture, which mixture is contacted with an alcohol extraction solvent, resulting in a first aqueous raffinate phase which is poor in &egr;-caprolactam and an alcohol phase which is rich in &egr;-caprolactam and which alcohol phase contains 6-aminocaproamide and/or 6-aminocaproamide oligomers, wherein the latter alcohol phase is subsequently contacted with water (backwash water) resulting in an alcohol extract phase poor in 6-aminocaproamide and/or 6-aminocaproamide oligomers and a second aqueous raffinate phase rich in 6-aminocaproamide and/or 6-aminocaproamide oligomers.

Process to separate &egr;-caprolactam from 6-aminocaproamide and 6-aminocaproamide oligomers

Process to prepare &egr;-caprolactam by treating 6-aminocaproic acid, 6-aminocaproate ester or 6-aminocaproamide or mixtures comprising at least two of these compounds in the presence of superheated steam in which a gaseous mixture comprising &egr;-caprolactam and steam is obtained, wherein the process is carried out in the absence of a catalyst at a temperature between 250 and 400&deg; C. and at a pressure of between 0.5 and 2 MPa. The invention also encompasses a process to prepare &egr;-caprolactam starting from 6-aminocapronitrile by performing a hydrolysis and a subsequent step as described above.

Process to prepare &egr;-caprolactam

Process to separate &egr;-caprolactam from an aqueous mixture containing &egr;-caprolactam and at least 0.5 wt % oligomers, wherein the separation is performed by extraction using an organic extraction agent. The aqueous mixture may be obtained in a process to prepare &egr;-caprolactam starting from 6-aminocapronitrile or in a process to prepare &egr;-caprolactam starting from 6-aminocaproic acid.

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Maastricht, Netherlands

Rudolf P M Guit