TUNING ALKYLATION REACTIONS WITH TEMPERATURE IN NEAR-CRITICAL WATER

Quantitative kinetics for the alkylation reactions of phenol and p-cre sol with tert-butyl alcohol in near-critical water as a function of te mperature are reported The reaction products of the alkylation reactio ns were ortho- and para-substituted phenols, which are used extensivel y as antioxidants in numerous polymer systems. A new experimental reac tion apparatus was designed, constructed, and successfully operated to allow pressure central and sampling of the reaction systems which pro vided rate constants in the temperature range 250 - 300 degrees C. Add itionally, activation energies and heats of formation were calculated from the temperature dependence of the rate constants, and ortho-subst itution was found to be exothermic whereas para-substitution was found to be endothermic. These results demonstrate that product distributio n of the alkylation reactions could be tuned with temperature to produ ce specific products.