Production of caprolactam, used in nylon manufacture, comprises gas-phase rearrangement of cyclohexanone oxime on a silica or zeolite catalyst treated or reactivated with acid

摘要

Production of epsilon-caprolactam (I) comprises gas-phase rearrangement of cyclohexanone oxime (II) on a solid catalyst comprising: (i) silica that has been treated or reactivated with an acidic aqueous solution of pH 1-6; or (ii) a crystalline zeolite that has been treated or reactivated with an acidic aqueous solution of pH 1-3. Independent claims are also included for the following: (1) A process for treating a solid catalyst with an acidic aqueous solution, comprising: (i) treating silica with a solution of pH 1-6; or (ii) treating a crystalline zeolite with a solution of pH 1-3. (2) A process for reactivating a solid catalyst that is losing its activity in the gas-phase production of (I) from (II), comprising (i) treating silica with an acidic aqueous solution of pH 1-6; or (ii) treating a crystalline zeolite with an acidic aqueous solution of pH 1-3. (3) A process for producing (I) from (II) using a silica with adjacent silanol groups (term not defined).