Friedel–Crafts hydroxyalkylation: reaction of anisole with paraformaldehyde catalyzed by zeolites in supercritical CO2

Supercritical CO2 has been found to be a very convenient reaction medium for the Friedel–Crafts hydroxyalkylation of anisole with paraformaldehyde. The high diffusion coefficients of molecules in the supercritical state are a crucial factor contributing to the catalytic activity when the reaction is carried out with microporous zeolites. Thus, the activity of mordenite for the hydroxyalkylation in supercritical CO2 at 60 °C is about threefold higher than that observed for the same zeolite in toluene at 110 °C.