Efficient metal-free oxidation of ethylbenzene with molecular oxygen utilizing the synergistic combination of NHPI analogues

• A novel metal- and initiator-free catalytic oxidation system was developed.
• The synergistic effect of NHQI and Car-NHPI enhanced the catalytic activities.
• The acid-base neutralization and radical exchange were main mechanistic profile.

A metal- and initiator-free catalytic system comprising N-hydroxyquinolinimide (NHQI) and 4-carboxyl-N-hydroxyphthalimide (Car-NHPI) was developed for the oxidation of ethylbenzene using molecular oxygen as the terminal oxidant. The catalytic activity of Car-NHPI/NHQI catalytic system was higher than that of Car-NHPI or NHQI alone. The high catalytic performance of Car-NHPI/NHQI catalytic system could be attributed to the dual interactions of radical exchange and acid-base neutralization, which resulted in the increment of the conversion of ethylbenzene up to 70% and the selectivity of acetophenone up to 66% at 120 °C under 1 atm O2 for 15 h.

Figure optionsDownload high-quality image (144 K)Download as PowerPoint slide