The epoxidation process of RBD palm oil was carried out using in situ generated performic acid. The effect of various
process variables such as the formic acid towards hydrogen peroxide mole ratio, the reaction temperature and the
reaction time were optimized by using response surface methodology (RSM). The D-optimal design was used to evaluate
the influence of process variables and their interaction in order to obtain the process optimum conditions. The results
showed that the optimum conditions of the epoxidation process were at 5.91 mole ratio of formic acid towards 3.60 mole
of hydrogen peroxide, reaction temperature of 40ºC and reaction time of 2.55 h. At the optimum condition, the epoxidised
RBD palm oil (EPO) yield was 86% with oxirane oxygen content (OOC) of 3.46%. The results showed in good agreement
with the predicted values from the RSM model.