Process for the production of epsilon caprolactam from 6-aminocaproic acid

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).