Highly Selective Synthesis of Phenol from Benzene over a Vanadium-Doped Graphitic Carbon Nitride Catalyst

Design and preparation of efficient and economical catalysts for direct hydroxylation of benzene to phenol is an important topic. In this work, a series of metal‐doped graphitic carbon nitride catalyst (Cu‐, Fe‐, V‐, Co‐, and Ni‐g‐C3N4) were successfully synthesized by using urea as the precursor through a facile and efficient method. The catalysts were characterized systematically using N2 adsorption–desorption, FTIR, thermogravimetric analysis, powder X‐ray diffraction, and X‐ray photoelectron spectroscopy techniques. It was found that the vanadium‐doped graphitic carbon nitride catalyst V‐g‐C3N4 was the most efficient catalyst for the direct synthesis of phenol from benzene with hydrogen peroxide as the oxidant and it could be recycled at least 4 times. The influence of reaction conditions such as the solvent, reaction temperature, reaction time, and the amounts of catalyst and hydrogen peroxide were investigated. Under optimized conditions, 18.2 % yield of phenol was obtained with the selectivity to phenol as high as 100 %. Sharpen your pencils…︁ A vanadium‐doped graphitic carbon nitride catalyst (V‐g‐C3N4) was successfully synthesized by using urea as the precursor through a facile and efficient method. The catalyst showed high activity in the hydroxylation of benzene with a selectivity to phenol of 100 %. The system can be recycled at least 4 times without considerable decrease in the efficiency.