Gilles Richner - In situ infrared monitoring of the solid/liquid catalyst interface during the three-phase hydrogenation of nitrobenzene over nanosized Au on TiO2

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      Publication Details (including relevant citation   information):

      Phys. Chem. Chem. Phys., 2011,   13, 12463-12471


      The three-phase hydrogenation of nitrobenzene catalysed by   nanosized gold over titania was investigated in a slurry.   Simultaneous in situ ATR-FTIR monitoring of the liquid phase and   at the solid/liquid catalyst interface identified the species   adsorbed on the catalyst and those in the liquid phase during the   reaction. Nitrosobenzene was not detected analytically while the   spectroscopic measurements strongly indicated phenylhydroxylamine   as an intermediate reacting before desorbing from the catalyst   surface. Under the same reaction conditions, azobenzene and   hydrazobenzene were identified as intermediates during the   hydrogenation of azoxybenzene to aniline. When nitrosobenzene or   phenylhydroxylamine was alternately fed as reactant, azoxybenzene   was produced via a disproportionation route. With the former,   azoxybenzene was not further reduced by hydrogen because   nitrosobenzene deactivated the catalyst. Combined with H2 uptake,   the spectroscopic measurements provided new insights into the   reaction mechanism of the gold catalysed hydrogenation of   nitrobenzene and an update of the corresponding kinetics.

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