Process for the preparation of caprolactam

Claim 1

A PROCESS FOR PRODUCING COPROLACTAM BY NITROSATION OF A CYCLOHEXYL COMPOUND HAVING A TERTIARY CARBON ATOM AND SELECTED FROM THE GROUP CONSISTING OF HEXAHYDROBENZOIC ACID AND THE FUNCTIONAL DERIVATIVES OF SAID ACID, IN THE PRESENCE OF CYCLOBEXANE AND OF A NITROSATION AGENT COMPRISING NITROSYLSALFURIC ACID AND CLEAN AND HAVING COMPOSITION DEFINED BY A MOLAR RATIO OF NO:TOTAL SO2 FROM 1:3 TO 1:5 AND A MOLAR RATIO OF TOTAL SO2:FREE SO2 FROM 1:01 TO 1:02, WHEREIN A REACTION MIXTURE INCLUDING A SOLUTION OF SAID CYCLOHEXYL COMPOUND AND THE NITROSATION AGENT IS CONTINUOUSLY FED INTO REACTOR MEANS AT ROOM PRESSURE, IS VIGOROUSLY AGIATED THEREIN TO CAME AS EXOTHERMIC NITROSATION REACTION TO BE MAINTAINED THEREIN, CAUSING CYCLOHEXANE TO DISTILL WATER REFLUX INTO SAID REACTOR MEANS WHEREBY THE REACTION TEMPERATURE IS LEVELLED TO SUBSTANTIALLY THE BOILING POINT OF CYCLOHEXANE, CONTINUOUSLY WITHDRAWING FROM SAID REACTOR MEANS REACTION PRODUCTS INCLUDING CAPROLACTION, SULFURIC ACID AND UNTEACTED CYCLOHEXYL COMPOUND IN CYCLOHEXANE, DECANTING SAID WITHDRAWN REACTION PRODUCTS TO SEPARATE CYCLOHEXANE THEREFROM, SUBJECTING THE REMAINING PRODUCTS TO EXTRACT CAPROLACTION THEREFROM, ADDING THE FURTHER REMAINING PRODUCTS INCLUDING THE UNREACTED CYCLOHEXYL COMPOUND AND FRESH CYCLOHEXYL COMPOUND TO SAID NITROSATION AGENT TO OBTAIN SAID SOLUTION, AND CONTINOUSLY FEELING SAID OBTAINED SOLUTION INTO SAID REACTOR MEANS TO CONTINOUSLY MAINTAIN THE SAID NITROSATION REACTION AT STRICTLY CONTROLLED TEMPERATURE IN THE NEIGHBORHOOD OF THE BOILING POINT OF CYCLOHEXANE UPON CONTINUOUSLY MAINTAINING THE SAID DISTILLATION UNDER REFLUX OF CYCLOHEXANE IN SAID REACTOR MEANS.