A Continuous-Flow O-Methylation of Phenols with Dimethyl Carbonate in a Continuously Fed Stirred Tank Reactor

A new continuous-flow methodology is reported for the selective O-methylation of phenol and p-cresol by using dimethyl carbonate as the methylating agent. The reaction has been performed by a continuously fed stirred tank reactor filled with a catalytic bed of poly(ethylene glycol) 1000 and K2CO3 as a base. Thus, operating at atmospheric pressure and at temperatures of 160−200 °C, the phenols have been transformed into their corresponding O-methylated derivatives (anisole and p-methylanisole, respectively) with substantially quantitative yields: under gradientless conditions, a space velocity of up to 9 × 10-2 h-1 was achieved.