Leevijit et al. [11] reported the effect of the residence time and the percentage of catalyst (NaOH) in the purity of methyl esters, for the palm oil methanolysis at 60 C and a methanol to oil ratio of 6:1 in a 6-stage continuously stirred tank reactor; such multi-stage perfectly well mixed reactor approaches the behavior of a plug-flow reactor when the number of stages goes to infinity