Stamicarbon B.v.

Stamicarbon B.v., Licensing Subsidiary of Dsm

Nicolaas F Haasen

Otto G Plantema

Cornelis G Van De Moesdijk

Arnold G Jetten

Peter F Rulkens

Gerardus M Wagemans

Process the recovering caprolactam from the residue remaining following the distillation, under reduced pressure, of impure caprolactam obtained by rearrangement of cyclohexanone oxime with sulphuric acid or oleum, by distilling the residue under reduced pressure whereby a caprolactam-containing distillate is obtained; hydrogenating the caprolactam containing distillate in an aqueous medium to obtain a hydrogenation product; and recovering caprolactam from the resulting hydrogenation product.

Recovery of caprolactam from caprolactam-containing distillation residue

A process is provided for recovering epsilon-caprolactam of a purity in excess of 99.9 wt. %, in a two-stage distillation operation. Each stage comprises an evaporator and a rectification column having a pressure drop across the theoretical trays thereof of less than about 2.5 MBAR.

Process for the purification of .epsilon.-caprolactam

An improved process is described for the reduction of ammonium ions, while avoiding any increase in nitrate ion concentration, in a liquid stream recycled between a zone of synthesis of hydroxyl ammonium salt and a zone for synthesis of oxime, wherein the liquid stream is contacted with a gas stream consisting essentially of nitrogen monoxide and containing nitrogen dioxide at a pressure above 1 atmosphere, at a temperature of at least 80.degree. C., such that after the contact the molar NO.sub.2 /NO ratio of the gas stream is within the range of between about 10.sup.-1 to 10.sup.-4 :1.

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Sittard, Netherlands

Nicolaas F Haasen