Allied Corporation

Rose M Federici

Frank Mares

James E Galle

Reginald T Tang

Reginald Y Tang

A process for selective preparation of lactams which comprises contacting, in the vapor phase, an aliphatic or aromatic aminonitrile having the formula HR.sub.1 N--D--CN wherein D is a divalent organic moiety and wherein R.sub.1 is (C.sub.1 -C.sub.4) alkyl or hydrogen with an effective amount of a silica catalyst, in the form of substantially spherical beads having a BET surface area greater than about 250 m.sup.2 /g, preferably between 300 and 500 m.sup.2 /g, and an average pore diameter less than about 20 nanometers preferably 8-10 nanometers at a temperature in the range of about 200.degree. to about 400.degree. C. and at a hydrogen or inert gas flow with a pressure in the range of about 0 to about 300 kPa, in the presence of: (a) ammonia in an amount equal to from 0 to about 50 mole percent of the molar amount of aliphatic or aromatic aminonitrile present; and (b) water in an amount from at least about 1.0 to about 50 times the molar amount of aliphatic or aromatic aminonitrile present for a time sufficient to produce the corresponding lactam is disclosed. The preferred aminonitrile is .epsilon.-aminocapronitrile. A process for the selective conversion of aliphatic or aromatic aminonitriles having the formula HR.sub.1 N--D--CN into the corresponding lactam in the presence of alkyl or aryl mononitrile or alkylene or arylene dinitriles by use of a silica catalyst, preferably a spherical silica catalyst with recovery of substantially all the alkyl or aryl mononitrile or alkylene or arylene dinitrile originally present is also disclosed.

Use of silica catalyst for selective production of lactams

Process for the selective conversion of dinitriles into the corresponding lactam by treating the dinitrile with an effective amount of a hydrogenation catalyst such as copper chromite in combination with a co-catalyst, such as titania, at a temperature in the range of from about 200.degree. C. to about 400.degree. C. and at a pressure of at least 50 kPa in the presence of water and hydrogen.

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Princeton, NJ, United States of America

Rose M Federici