8
H. Falcon et al. / Catalysis Communications 12 (2010) 5–8
p-xylene with molecular oxygen to TPA has been efficiently
performed under very mild reaction conditions (373 K and 1 bar)
using different N-hydroxyimides (NHPI, NHMI, NHNI, NHSI, and
CATPE) and Co and Mn salts as homogeneous catalysts; (ii) the time at
which the peak concentration of p-TOA is reached and the slope of its
decay at longer reaction times depend heavily on the N-hydroxyimide
catalyst used; (iii) the catalytic activity of the tested N-hydroxyimides
in the target reaction is related to the bond dissociation energy (BDE)
of NO–H: NHNINNHSI≫NHPINNHMI; the only exception to this rule
is NHNI, which appears to be due to its limited solubility in the liquid-
phase under the conditions selected in this work.
Acknowledgement
We thank our research sponsor, The King Saud University, Riyadh
(Saudi Arabia).
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4. Conclusions
From both the approach and results obtained in this work, the
following conclusions can be drawn: (i) the liquid-phase oxidation of