Microwave-Assisted Process Intensification of Synthesis of Thymol Using Carbonized Sulfonic Acidic Resin (CSA) Catalyst

A continuous method for the preparation of thymol was developed, using a carbonized sulfonic acid (CSA) resin as the catalyst, under the influence of microwaves. A premixed solution of iso-propyl alcohol (IPA) and m-cresol was passed through a fixed catalyst bed reactor, which was irradiated by microwaves. The molar ratio of reactants, the microwave power, and the contact time were varied for their effect on the conversion of m-cresol and selectivity toward thymol. A complete conversion of m-cresol was obtained within a contact time of 3 min at 1:5 molar ratio of m-cresol to IPA. The kinetics of the reaction was studied separately in a batch reactor, and a Langmuir-Hinshelwood-Hougen-Watson (L-H-H-W) surface-reaction-rate-controlled model was used to represent the kinetic data.