Preparation of lactam by gas phase cyclizing hydrolysis of aminonitrile, useful e.g. as solvent and in polyamide production

摘要

Preparation of lactams by gas phase cyclizing hydrolysis of aminonitriles is carried out in the presence of a metal phosphate catalyst comprising oligophosphate(s) (I) of group 3 and/or 4 metal(s), including lanthanide(s), and optionally their salt(s) (II) with an inorganic acid. Preparation of lactams by gas phase cyclizing hydrolysis of aminonitriles is carried out in the presence of a metal phosphate catalyst comprising oligophosphate(s) of formula M(POa)b (I) of group 3 and/or 4 metal(s), including lanthanide(s), and optionally their salt(s) (II) with an inorganic acid; M = a group 3 or 4 metal, including lanthanides; a = 2.5-4.0; b = a value giving a neutral charge. Independent claims are also included for (a) the preparation of the catalyst; and (b) the use of (I) and optionally (II) as catalysts in this process, especially in caprolactam production.