TY  - JOUR
A1  - Bock, Hans
A1  - Berkner, Bodo
T1  - Gasphasen-Reaktionen, 91 [1-3]. Thermische und heterogen-katalysierte N₂-Abspaltung aus Azo-Verbindungen R–N=N–R (R = CH₃, C₃H₅, C₆H₅)
T1  - Gas phase reactions, 91 [1-3]. Thermal and heterogeneously catalyzed N₂ elimination of azo-compounds R–N=N–R (R = CH₃, C₃H₅, C₆H₅)
T2  - Zeitschrift für Naturforschung, B
N2  - Thermal decompositions of azo compounds in the gas phase under reduced pressure are further investigated using photoelectron spectroscopic gas analysis. Passing diallyl, diphenyl and phenylmethyl derivatives either through a short-pathway pyrolysis (SPP) apparatus or through an external thermal reactor (ETR) results in the following fragmentations: Under nearly unimolecular conditions (SPP, 10-4 mbar pressure), diallyldiazene decomposes above 600 K to N2 and hexadiene-1,5 with the allyl radical as a detectable intermediate. The PE spectra recorded for diphenyldiazene above 1000 K (ETR, 1-2 mbar pressure) show N2, benzene, as well as traces of diphenyl. Phenylmethyldiazene yields above 800 K (SPP) predominantly N2, toluene, diphenyl and ethane with the methyl radical as the only detectable intermediate. Insertion of quartz wool into the pyrolysis tube (ETR) lowers the fragmentation temperatures, and in addition, above 850 K, HCN and aniline are PE spectroscopically identified. Surprisingly, this second reaction channel can be heterogeneously catalyzed: phenylmethyldiazene decomposes under 10-2 mbar pressure at a [Ni/SiO2] catalyst surface selectively to HCN and aniline.
KW  - Azo Compounds
KW  - Photoelectron Spectra
KW  - Gas Phase Thermolysis
KW  - Heterogeneous Catalysis
Y1  - 2014
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/62033
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-620330
SN  - 1865-7117
SN  - 0932-0776
VL  - 47.1992
IS  - 11
SP  - 1551
EP  - 1560
PB  - Verlag der Zeitschrift für Naturforschung
CY  - Tübingen
ER  -