US 11,753,372 B2
Process for the production of epsilon caprolactam from 6-aminocaproic acid
Michele Cecchetto, Arco (IT); Anacleto Dal Moro, Arco (IT); Lauri Hannunpoika Suominen, San Diego, CA (US); and Michael Japs, San Diego, CA (US)
Assigned to AQUAFIL S.P.A., Arco (IT); and GENOMATICA INC., San Diego, CA (US)
Appl. No. 17/418,060
Filed by AQUAFIL S.P.A., Arco (IT); and GENOMATICA INC., San Diego, CA (US)
PCT Filed Dec. 23, 2019, PCT No. PCT/IB2019/061270
§ 371(c)(1), (2) Date Jun. 24, 2021,
PCT Pub. No. WO2020/136547, PCT Pub. Date Jul. 2, 2020.
Claims priority of application No. 102018000021409 (IT), filed on Dec. 28, 2018.
Prior Publication US 2022/0089536 A1, Mar. 24, 2022
Int. Cl. C07D 201/08 (2006.01)
CPC C07D 201/08 (2013.01) 30 Claims
 
1. A process for the production of epsilon caprolactam from 6-aminocaproic acid, the process including the following steps:
step (i)—pre-treating a starting material comprising 6-aminocaproic acid in order to prepare it for step (ii)—the cyclization, whereby the starting material is pre-heated to the temperature in or near the temperature of a cyclization reactor of step (ii) to accelerate a cyclization reaction in step (ii);
step (ii)—feeding the pre-treated starting material obtained in step (i) under a controlled flow rate into a cyclization reactor and continuously contacting said starting material with a constant flow of superheated steam in the presence of a catalyst, wherein cyclization of 6-aminocaproic acid to epsilon caprolactam occurs and wherein stream-stripping of a vapor mixture comprising epsilon caprolactam and water occurs continuously with the superheated steam, wherein the cyclization reactor is at a pressure and temperature favouring cyclization and steam-stripping;
step (iii)—condensing the vapour mixture comprising epsilon caprolactam and water obtained from step (ii) to obtain an aqueous solution of epsilon caprolactam;
wherein in step (i) the starting material comprises:
6-aminocaproic acid in a form of a solution in water with the concentration of 6-aminocaproic acid at least 50 wt. % based on the total mass of the starting material; or
6-aminocaproic acid in an isolated powdered form, wherein said starting material is heated in a pre-melter to a temperature of 210-260° C., whereby a molten 6-aminocaproic acid with no water is obtained and is then fed into the cyclization reactor of step (ii).