A continuous-flow O-methylation of phenols with dimethyl carbonate in a continuously fed stirred tank reactor

A new continuous-flow methodology is reported far 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 degrees 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 x 10(-2) h(-1) was achieved.