Continuous Chemoselective Methylation of m‐Cresol and Phenol with Supercritical Methanol over Solid Acid and Base Metal Oxide Catalysts

The chemoselective methylation of m-cresol and phenol with supercritical methanol (scCH 3 OH) promoted by metal oxide catalysts (MgO, ZrO 2 , Cs-P-Si and Fe-V/SiO 2 ) was investigated in a continuous flow fixed bed reactor. The use of scCH 3 OH as a carrier medium led to a significant change in the product selectivity compared to that attained in the gas phase reaction, and caused a marked suppression of the degradation of CH 3 OH during the reaction, resulting in an improvement in the catalyst lifetime. -The chemoselective outcome of the reaction was highly influenced by the acid-base character on the solid catalysts examined under supercritical conditions.