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Acid‐Catalyzed Decomposition of the Benzyl Nitrite Intermediate in HNO 3 ‐Mediated Aerobic Oxidation of Benzyl Alcohol
Author(s) -
Aellig Christof,
Neuenschwander Ulrich,
Hermans Ive
Publication year - 2012
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201100439
Subject(s) - benzyl alcohol , cyclohexanol , chemistry , benzaldehyde , decomposition , cyclohexanone , catalysis , nitrite , inorganic chemistry , organic chemistry , photochemistry , medicinal chemistry , nitrate
Abstract Benzyl nitrite (PhCH 2 ONO) was previously identified as the pivotal intermediate in the HNO 3 ‐mediated oxidation of benzyl alcohol. Its acid‐catalyzed decomposition yields benzaldehyde and HNO, the precursor of undesirable N 2 O. Most likely, an analogous mechanism is responsible for the formation of N 2 O during the oxidation of cyclohexanol and cyclohexanone to adipic acid, the largest industrial source of this important greenhouse gas. In this paper, the decomposition of benzyl nitrite is studied in more detail, allowing the kinetic isotope effect and the influence of substituents to be determined. A linear Evans–Polanyi correlation between the measured Arrhenius activation energies and the computed reaction energies was established. Furthermore, the differences in the reactivities of the substituted benzyl nitrites are reflected in the oxidation of the corresponding alcohols, and also affect the rate‐determining step in the overall mechanism. The results of this study corroborate the importance of the nitrite intermediate in HNO 3 ‐based oxidation technology.