title: Beckmann rearrangement of 15N-cyclohexanone oxime on zeolites silicalite-1, H-ZSM-5, and H-[B]ZSM-5 studied by solid-state NMR spectroscopy.
abstract: By means of solid-state 15N NMR spectroscopy, evidence for the formation of nitrilium ions as intermediates of the Beckmann rearrangement of 15N-cyclohexanone oxime to epsilon-caprolactam on silicalite-1, H-ZSM-5, and H-[B]ZSM-5 is reported. The zeolites under study are characterized by different acid strengths (silicalite-1 < H-[B]ZSM-5 < H-ZSM-5). Depending on the nature of catalytically active surface OH groups, reactant and product molecules exist in the nonprotonated or protonated state. In addition, formation of byproducts such as 5-cyano-1-pentene and epsilon-aminocapric acid as a result of dehydration and hydrolysis of the reactant and product molecules, respectively, were observed.
authors.affiliation: Institute of Chemical Technology, University of Stuttgart, D-70550 Stuttgart, Germany.
authors.forename: V R Reddy
authors.initials: VR
authors.lastname: Marthala
authors.forename: Yijiao
authors.initials: Y
authors.lastname: Jiang
authors.forename: Jun
authors.initials: J
authors.lastname: Huang
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Roger
authors.initials: R
authors.lastname: Gläser
authors.forename: Michael
authors.initials: M
authors.lastname: Hunger