CAPROLACTAM PRODUCTION PROCESS Russian patent published in 2000 - IPC

FIELD: industrial organic synthesis. SUBSTANCE: caprolactam is prepared by liquid-phase interaction of 6- aminocapronitrile with water at elevated temperature. Catalyst-free reaction mixture is heated in reactor A to form mixture I consisting largely of water, caprolactam, and high-boiling fraction. Mixture I is converted into mixture II by removing water to leave largely caprolactam and high-boiling fraction. Mixture II is then separated by distillation into indicated constituents. Separated high-boiling fraction is processed according to three versions: fraction is returned into reactor A; fraction is treated in reactor B; or fraction is processed in reactor C under reduced pressure in presence of base. Reaction mixtures from reactors B and C are distilled to give additional amount of caprolactam according to the same scheme, which is used to treat reaction mixture from reactor A. Process in reactor A is carried out at 200-370 C and pressure 0.1 to 50 MPa with excess water 10 to 150 mol per 1 mol of nitrile. EFFECT: simplified technology due to lack of catalyst separation and regeneration stage, and minimized formation of by-products. 6 cl, 4 ex