Interaction of Acetonitrile with Olefins and Alcohols in Zeolite H-ZSM-5: In situ Solid-State NMR Characterization of the Reaction Products
Chemistry - A European Journal
, E-ISSN: 1521-3765
||alcohols, nitriles, NMR spectroscopy, olefins, zeolites
Stepanov Alexander G.
Luzgin Mikhail V.
Laboratory for the Study of the Mechanisins of Catalytic Reactions
Boreskov Institute of Catalysis Siberian Branch of the Russian Academy of Sciences
Prospekt Akademika Lavrentieva 5. Novosibirsk 630090 (Russia)
Russian Foundation for Basic Research
The reaction products and intermediates from the interaction of acetonitrile with olefins (oct-1-ene) or alcohols (tert-butyl alcohol) in zeolite H-ZSM-5 at 296 K have been characterized with 13C and 15N solid-state NMR. It has been shown that coadsorption of acetonitrile and olefin on H-ZSM-5 gives rise to the intermediate N-alkylnitrilium cation represents a persistent species inside a zeolite under anhydrous conditions. Upon admittance of water to the pores of the zeolite, the N-alkylnitrilium cation slowly converts into N-alkylamide in accordance with the classic Ritter reaction. In the case of acetonitrile and alcohol, just after coadsorption both the intermediate N-alkylnitrilium cation and the final N-alkyl-amide are identified simultaneously; the former slowly disappears over a few days. Thus, 1) it has been shown that the Ritter reaction can occur not only in liquid acidic media but also on a solid acid catalyst, zeolite H-ZSM-5; 2) N-alkylnitrilium cations have been detected and characterized with solid-state NMR as persistent intermediates in the Ritter reaction for the first time while the reaction proceeds.