Preparation of lactams

Abstract

Lactams, in particular epsilon-caprolactam (a basic starting material for the production of nylon 6), are selectively prepared by cyclizing/reacting the corresponding aminonitriles with water, in the presence of a catalytically effective amount of a deactivation-resistant solid metal phosphate having the general formula (II): MH.sub.h (PO.sub.4).sub.n .multidot.(Imp).sub.p in which M is a divalent, trivalent, tetravalent or pentavalent element selected from among those of Groups 2a, 3b, 4b, 5b, 6b, 7b, 8, 2b, 3a, 4a and 5a of the Periodic Table, or mixture thereof, or M=0; Imp is a basic impregnating compound which comprises an alkali or alkaline earth metal, or mixture thereof, together with an electrical neutrality-ensuing counteranion therefor; n is 1, 2 or 3; h is 0, 1 or 2; and p is a number ranging from 0 to 1/3, corresponding to the molar ratio between the moiety Imp and the moiety MH.sub.h (PO.sub.4).sub.n.

Dependencies are inferred from the claim text.