Anisole hydrolysis in high temperature water

Abstract

We investigated the hydrolysis of anisole to phenol in high-temperature water with and without water-tolerant Lewis acid catalysis. With no catalyst present, anisole hydrolyzes to phenol in 97% yield after 24 hours at 365 °C, our experimentally determined optimal temperature and time. Experiments with varied water density and analysis of comparable literature data suggest that anisole hydrolysis is almost third order in water, when the S(N)2 mechanism dominates. Of the water-tolerant Lewis acid catalysts studied, In(OTf)(3) offered the best phenol yield. Anisole hydrolysis was first order in catalyst and first order in substrate. Introducing In(OTf)(3) catalysis lowered the activation energy for anisole hydrolysis to 31 ± 1 kcal mol(-1). Anisole hydrolysis in high-temperature water with In(OTf)(3) catalysis is competitive with other techniques in the literature based on rate and yield. In the presence of 5 mol% In(OTf)(3) catalyst, anisole hydrolyzes to phenol in 97% yield after 90 minutes at 300 °C.