Method for preparing lactames, comprising a photonitrosation step, followed by a Beckmann transposition step

Patent metadata

Field	Value
Publication number	US-9499481-B2
Application number	US-201414252610-A
Country	US
Kind code	B2
Filing date	Apr 14, 2014
Priority date	May 26, 2008
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

The invention relates to a method for preparing lactames, according to which a photonitrosation of a cycloalkane is carried out using nitrosyl chloride (NOCI). According to the invention, said photonitrosation is carried out by means of LEDs emitting a monochromatic light. The method according to the invention can also include a step comprising Beckmann transposition/dechlorination of the oxime hydrochloride generated during said phonitrosation, preferably carried out in a glass microreactor.

First claim

The invention claimed is:

1. In a process for preparing lauryllactam or caprolactam from oximes, comprising photonitrosating of a cycloalkane using nitrosyl chloride (NOCI), the improvement wherein said photonitrosating is carried out by exposing the cycloalkane to LEDs emitting a monochromatic light.

2. The process as claimed in claim 1 , in which the cycloalkane is cyclododecane.

3. The process as claimed in claim 1 , wherein the monochromatic light emitted by the LEDs has an average wavelength value included in a range from 550 to 650 nm.

4. The process as claimed in claim 3 , wherein the monochromatic light emitted by the LEDs has an average wavelength value of from 585 to 595 nm.

5. The process as claimed in claim 1 , wherein a microreactor is used to carry out the photonitrosation of the cycloalkane.

6. The process as claimed in claim 5 , wherein the body of the microreactor is made of glass.

7. The process as claimed in claim 1 , wherein the lactam is prepared from the oxime by Beckmann rearrangement/dechlorination of the oxime hydrochloride generated during photonitrosation, and a microreactor is used to carry out a Beckmann rearrangement/dechlorination step.

8. The process as claimed in claim 7 , wherein the body of the microreactor comprises tantalum, a fluoropolymer, a glass steel or glass.

9. A process for preparing lauryllactam or caprolactam, comprising preparing an oxime by photonitrosation of a cycloalkane using nitrosyl chloride in the presence of LEDs emitting monochromatic light, and subjecting oxime hydrochloride generated during photonitrosation to Beckman rearrangement/dechlorination to produce lauryllactam or caprolactam.

10. The process as claimed in claim 9 , in which the cycloalkane is cyclododecane.

11. The process as claimed in claim 9 , wherein the body of the microreactor is made of glass.

Assignees

• Arkema France

Inventors

• Aubert Thierry

Classifications

• C07D227/087

  One doubly-bound oxygen atom in position 2, e.g. lactams · CPC title

• C07D201/04 Primary

  from or via oximes by Beckmann rearrangement · CPC title

• C07C249/06

  by nitrosation of hydrocarbons or substituted hydrocarbons · CPC title

• C07D201/10 Primary

  from cycloaliphatic compounds by simultaneous nitrosylation and rearrangement · CPC title

• C07C2601/20

  the ring being twelve-membered · CPC title