Continuous flow photooxidation of alkyl benzenes using fine bubbles for mass transfer enhancement

Selective photooxidation of alkyl benzenes was studied in a custom-built continuous flow photochemical reactor equipped with fine bubble generator and low power UV light source. Fine bubbles air were used as an oxidizing agent along water-soluble sodium anthraquinone sulfonate catalyst. The containing slug-flow system using 1.4 times more efficient at lower feed-flow rate 2 mL/min 1.8 higher 5 mL/min. Ethylbenzene selectively oxidized to acetophenone room-temperature, 90% ethylbenzene conversion 92% selectivity acetophenone, short residence time min. enhanced gas/liquid mass transfer afforded by the significantly increased productivity, giving rise high yield. Due greater efficiency, compressed can be oxidant instead pure O2, thus alleviating potential safety concerns making process safer amenable for scale up.