Method for producing ε-caprolactam

Patent metadata

Field	Value
Publication number	US-12365652-B2
Application number	US-202017777739-A
Country	US
Kind code	B2
Filing date	Nov 18, 2020
Priority date	Nov 19, 2019
Publication date	Jul 22, 2025
Grant date	Jul 22, 2025

Abstract

The present invention relates to a method of producing ε-caprolactam, the method including the following steps (A) and (B): (A) a step of reacting 5-cyanovaleramide with hydrogen in an aqueous solvent in a presence of a hydrogenation catalyst to obtain a 5-cyanovaleramide hydrogenation reaction mixture; (B) a step of heating the 5-cyanovaleramide hydrogenation reaction mixture at a temperature of 180° C. or higher and 300° C. or lower in an aqueous solvent to obtain ε-caprolactam.

First claim

The invention claimed is:

1. A method of producing ε-caprolactam, the method comprising the following steps (A) and (B):
(A) a step of reacting 5-cyanovaleramide with hydrogen in an aqueous solvent in a presence of a hydrogenation catalyst to obtain a 5-cyanovaleramide hydrogenation reaction mixture;
(B) a step of heating the 5-cyanovaleramide hydrogenation reaction mixture at a temperature of 180° C. or higher and 300° C. or lower in an aqueous solvent to obtain ε-caprolactam.

2. The method according to claim 1 , wherein the step (A) is performed in an absence of ammonia.

3. The method according to claim 1 , wherein a reaction temperature in the step (A) is 50° C. or higher and 200° C. or lower.

4. The method according to claim 1 , wherein the temperature of the step (B) is 200° C. or higher and lower than 280° C.

5. The method according to claim 1 , wherein the step (B) is performed in an absence of a catalyst.

6. The method according to claim 1 , wherein a ratio of 6-aminocaproic acid amide contained in the 5-cyanovaleramide hydrogenation reaction mixture is 45 mol % or more and 72 mol % or less.

7. An ε-caprolactam composition having a ratio of 6-aminocaproic acid amide to ε-caprolactam of 0.1 mol % or more and 5 mol % or less, and comprising no ammonia.

Assignees

• Toray Industries

Inventors

• Tsukamoto Daijiro
• Kawamura Kenji
• Yamada Katsushige
• Akahira Masato
• Yamamoto Daisuke

Classifications

• C07C227/12

  Formation of amino and carboxyl groups · CPC title

• C07D223/10 Primary

  attached in position 2 · CPC title