Process for the preparation of ε-caprolactam
AssigneeDsm N.V.
InventorsFrank P. W. Agterberg, Rudolf P. M. Guit, Matthias R. J. Offermanns
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Abstract
A process for the preparation of ε-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)-ε-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).
Claims19
A process for the preparation of ε-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, wherein the process is performed in the presence of N-(5-carboxypentyl)-ε-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), wherein said derivative has the structural formula
- where R′ is NH2 or OR1;
- n is at least 1;
- R″ is OH, NH2 or OR1;
- and
- R1 is an organic group with 1 to 20 carbon atoms.
A method for enhancing the reaction rate for the conversion of 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 to ε-caprolactam, which comprises carrying out the conversion reaction in the presence of a rate-enhancing effective amount of N-(5-carboxypentyl)-ε-caprolactam and/or derivative thereof wherein said derivative has the structural formula
- where R′ is NH2 or OR1;
- n is at least 1;
- R″ is OH, NH2 or OR1;
- and
- R1 is an organic group with 1 to 20 carbon atoms.
A composition comprising (a) ε-caprolactam and (b) N-(5-carboxypentyl)-ε-caprolactam, wherein the amount of component (b) in the composition is higher than 0.1 wt. % and lower than 50 wt % (based on the total composition).
A process for the preparation of polyamide-6 starting from water and 6-aminocaproic acid, 6-aminocaproamide, 6-aminocaproic ester, 6-aminocapronitrile and/or ε-caprolactam, wherein the process is performed in the presence of N-(5-carboxypentyl)-ε-caprolactam and/or derivative thereof in an amount of less than 50 wt % and more than 0.1 wt %, wherein said derivative has the structural formula
- where R′ is NH2 or OR1;
- n is at least 1;
- R″ is OH, NH2 or OR1;
- and
- R1 is an organic group with 1 to 20 carbon atoms.
A method for enhancing the reaction rate of a reaction mixture of water and ε-caprolactam, 6-aminocaproic acid, 6-aminocaproamide, 6-aminocaproic ester and/or 6-aminocapronitrile to prepare polyamide-6 which comprises adding a reaction-rate enhancing amount of N-(5-carboxypentyl-ε-caprolactam and/or derivative thereof to the reaction mixture, wherein said derivative has the structural formula
- where R′ is NH2 or OR1;
- n is at least 1;
- R″ is OH, NH2 or OR1;
- and
- R1 is an organic group with 1 to 20 carbon atoms.
Dependencies are inferred from the claim text.