Direct phenol synthesis by catalytic oxidation of benzene with molecular oxygen

Phenol is an important synthesis intermediate in chemical industry. Currently, phenol is produced from isopropylbenzene oxidation process, which consumes propylene and forms acetone as by-product. Phenol synthesis from the direct catalytic oxidation of benzene by molecular oxygen is attractive from the standpoint of its potential economical benefit, social benefit as well as environmental benefit. However, the research works in this field are still regarded as one of the most difficult challenges for both catalysis and organic synthesis. This mini-review systematically summarizes the progress of direct phenol synthesis by catalytic oxidation of benzene using molecular oxygen as oxidant, with emphasis on the explored catalysts such as Pd, Cu, V compounds. We also outline the factors affecting phenol synthesis and the possible reaction mechanisms on different catalysts. In addition, some suggestions are given for future investigation on direct phenol synthesis by catalytic oxidation of benzene with molecular oxygen.