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

Inactive Publication Date: 2011-06-09
ARKEMA FRANCE SA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0036]By virtue of this second aspect of the invention, it is possible to carry out Beckmann rearrangements / dechlorinations under conditions for precise control of flow rate, of temperature and of residence time of the reactants, which increases the safety and the yield of this reaction.
[0071]Typically, the microreactors used can be in the form of a plate of which the surface area is between 100 and 2500 cm2; they have channels of which the diameter is between 50 microns and 10 mm and a system of heating by means of a heat-transfer fluid which makes it possible to achieve temperatures that can reach 250° C.

Problems solved by technology

In addition, LEDs do not contain any mercury, which is an extremely toxic product, the use and the complex recycling of which further increases the cost of use.

Method used

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

Examples

Experimental program
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Effect test

example 1

Photonitrosation of Cyclododecane by Means of LEDs

[0073]3806 g of a solution containing 32% by mass of cyclododecane in carbon tetrachloride and 200 g of sulfuric acid at 90% are introduced, with stirring, into a two-liter reactor equipped at its center with a bundle of 80 Luxeon LXML-PL01-0030 LEDs from the company Philips Lumileds, each supplying 30 lumens (for a current of 350 mA) and emitting a monochromatic light centered at 590 nm, the lamps are turned on, and then 10 l / h of anhydrous hydrochloric acid gas and 10 l / h of nitrosyl chloride are introduced continuously for 3 h, while cooling the reaction medium such that the temperature does not exceed 25° C.

[0074]The selectivity of the reaction, expressed by the ratio of the percentage of cyclododecanone oxime to the sum of the percentage of cyclododecanone oxime and of by-products of the reaction, assayed by HPLC in the sulfuric acid phase, is 89%, and therefore greater than that observed when using the mercury-vapor or sodium-v...

example 2

Beckmann Rearrangement / Dechlorination

[0075]90% sulfuric acid is injected, at a flow rate of 1 1 / h and at ambient temperature, with a Grundfos DME-2-18 feed pump into a microstructure of “DT” type having an internal volume of 9 ml (reactive circuit), manufactured by the company Corning and described, for example, in the article: Chem. Eng. Technol. 2008, 31, No. 8, 1146-1154 by P. Barthe et al.[0076]The heat-transfer fluid circuit is injected, at a flow rate of 6 with oil which is at 205° C. by means of a Lauda Integral XT 350 HW bath. Once the temperature of 200° C. has been reached at the outlet of the microstructure in the heat-transfer fluid circuit, the injection of sulfuric acid is stopped and a solution containing 30.1% (by mass) of cyclododecanone oxime (determined by HPLC) in 90% sulfuric acid is injected at a flow rate of approximately 2.5 1 / h by means of two Grundfos DME-2-18 pumps mounted in parallel.[0077]After 25 minutes during which 1017.9 g of oxime solution have been...

example 3

Beckmann Rearrangement / Dechlorination

[0081]90% sulfuric acid is injected, at a flow rate of 1 l / h and at ambient temperature, with a Grundfos DME-2-18 feed pump, into 4 microstructures, mounted in series, of “DT” type; each having an internal volume of 9 ml (reactive circuit), manufactured by the company Corning and described, for example, in the article Chem. Eng. Technol. 2008, 31, No. 8, 1146-1154 by P. Barthe et al.[0082]- The heat-transfer fluid circuit is injected, at a flow rate of 6 I / min, with oil which is at 190° C. by means of a Lauda Integral XT 350 HW bath. Once the temperature of 185° C. has been reached at the outlet of the microstructure in the heat-transfer fluid circuit, the injection of sulfuric acid is stopped and a solution containing 30.9% (by mass) of cyclododecanone oxime (determined by HPLC) in 90% sulfuric acid is injected at a flow rate of approximately 1 l / h by means of 1 Grundfos DME-2-18 pump.[0083]After 1 hour during which 766 g of oxime solution have ...

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Abstract

The invention relates to a method for preparing lactames, according to which a photonitrosation of a cycloallcane 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.

Description

FIELD OF THE INVENTION [0001]The present invention relates to a process for preparing lactams, comprising, in particular, a step of photonitrosation of cycloalkanes in the presence of light-emitting diodes, referred to as LEDs in the rest of the text, followed by a Beckmann rearrangement step carried out in a microreactor, preferably in a glass microreactor.PRIOR ART AND TECHNICAL PROBLEM [0002]The industrial usefulness of lactams is known. By way of example, caprolactam and lauryllactam are precursors of polyamides 6 and 12, respectively.[0003]At the industrial level, a process for synthesizing a lactam from a cycloalkane can successively implement the following two reaction steps:[0004]in a first reaction step, a photonitrosation of the cycloalkane is carried out using nitrosyl chloride (NOCl). This photonitrosation is generally carried out in an organic solvent / sulfuric acid two-phase medium using mercury lamps or sodium lamps. An oxime is thus produced in the organic phase and i...

Claims

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Application Information

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IPC IPC(8): C07D225/02C07C201/06
CPCC07D201/04C07D227/087C07D201/10C07D225/02C07C249/06C07C2601/20C07C251/44
Inventor AUBERT, THIERRY
Owner ARKEMA FRANCE SA
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