Oil palm empty fruit bunch (EFB) was successfully phenolyzed in the presence of sulfuric acid as a catalyst at different temperatures, reaction times, and percentage of catalyst used. Sulfuric acid was used as catalyst (5 and 8%) at the reacting temperature of 110-150 degrees C with various reaction times. The kinetics parameters along with the weight of reacted EFB and phenol were calculated using the second- and third-order reaction kinetics models. The weight of the reacted EFB in phenol shows that about 97% of EFB was liquefied during the reaction. However, only 70% of phenol was reacted with EFB. The kinetic studies showed that the EFB phenolysis in the presence of sulfuric acid followed a bimolecular type of the secondorder reaction. The activation energy calculated from the Arrhenius equation was 50.7 and 18.06 kJ/mol when the catalyst concentration was 5 and 8%, respectively. It can be depicted that the activation energy decreased as the catalyst increased. The reaction enthalpy showed that the liquefaction of EFB in phenol had dominantly followed the endothermic reaction. (c) 2007 Wiley Periodicals, Inc.