PROCESSO PARA PURIFICAR CAPROLACTAMA

The invention relates to a process for purifying caprolactam (CL) which was obtained by Beckmann rearrangements or by nitrosation of cyclohexyl compounds. The process is characterised in that the following steps are carried out: (a) treatment of the caprolactam oil with ammonia at a pH between 8 and 10 with addition of at least one surface-active agent (b) extraction of the aqueous-ammoniacal solution obtained as in (a) with toluene (c) extraction of the solution of caprolactam in toluene obtained as in (b) with water (d) dehydration of the product obtained as in (c) by distillation of water and rectification in vacuo in packed columns with separation of low-boiling and high-boiling by-products in two successive phases (e) treatment of the caprolactam obtained as in (d) with an alkali metal and/or alkaline earth metal hydroxide (alpha) until an alpha/CL weight ratio of 0.0125 to 0.100 equivalents of alpha per kg of CL is obtained and subsequent retention and mixing in an inert gas atmosphere for at least 150 minutes at a temperature of between 80 and 160@C and (f) rectification of the mixture obtained as in (e) in vacuo with obtainment of pure caprolactam.