Snia Viscosa Societa Nazionale Industria Applicazioni Viscosa S.p.a.

Mario Catoni

Paolo Senni

Pier P Rossi

Domenico Astarita

Roberto Mattone

Process for the preparation of .omega.-lactams (in particular caprolactam) ith improved yields, by reaction of cycloaliphatic derivatives having the general formula: ##STR1## wherein n=3-13 with nitrosating agents in the presence of dehydrating agents, characterized by the fact that the reaction is carried out a low temperature which is constant between stages, and in all the zones of a stage and with particular concentrations of the dehydrating agent.

Process for the preparation of .omega.-lactams, in particular caprolactam

A process for the purification of raw caprolactam obtained by extraction h alkylated phenols from its sulphuric solution, re-extraction with water, oxidation preferably with KMnO.sub.4, evaporation of water and distillation, comprises, before the oxidation treatment, a 'fast distillation', in the presence of an alkali. The oxidation is conducted at 0.degree.-80.degree. C. and at atmospheric pressure with 0.005-0.5% by weight of KMnO.sub.4. The amount of alkali (NaOH) used in the fast distillation is comprised between 0.05 and 0.5% by weight.

Process for the purification of raw caprolactam

There is described a process for the purification of caprolactam from the idable impurities present therein, by means of a treatment with an oxidizing agent consisting of ozone, the process comprising the steps of dissolving the polluted caprolactam into a solvent inert to ozone, such as water, and of causing the ozone to bubble through the resulting solution, the concentration of the caprolactam in the solution being preferably comprised between about 40% and 78% by weight of caprolactam, and the treatment being preferably effected at a temperature between the freezing temperature of the solution and 70.degree. C.

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Colleferro, Italy

Mario Catoni