A method for obtaining thymol by gas phase catalytic alkylation of m-cresol over zinc aluminate spinel

The gas-phase catalytic alkylation of m-cresol with isopropanol on ZnAl₂O₄ catalysts of different properties has been studied. The reactions were carried out in a continuous process at atmospheric pressure in the temperature range of 473–583 K. Both, O- and C-alkylated products were obtained at lower temperatures while at higher temperatures thymol was the main product of the reaction. According to the elaborated method thymol can be efficiently obtained with selectivity reaching up to 88.4% at an m-cresol conversion of 78.2%.