Selective Lignin Oxidation towards Vanillin in Phenol Media

Selective lignin oxidation reaction to produce vanillin was carried out in phenol media with a catalyst of Upsilon-Al2O3 supported ReOx nanoparticles. A vanillin yield of 7.3wt% was achieved under moderate reaction conditions of (1208 degrees C and 2 bar oxygen) according to GC ananlysis. The vanillin selectivity is higher than 95.0%. The catalyst could be separated conveniently from the product mixture and re-used with sustainable activity in the processes.