Therefore, a two step process, acid-catalyzed esterification process and followed by base-catalyzed transesterification process, were selected for converting CJCO to methyl
esters of fatty acids. The first step was acid esterification
and pretreatment for removing FFA in the oil, which is
mainly a pretreatment process, which could reduce the
FFA. It was reported that to get complete FFA esterification in some vegetable oils, could be done in the reaction
temperature 50 C. The process was intended to convert
FFA to esters using an acid catalyst (H2SO4 1% w/w) to
reduce the FFA concentration of CJCO below 2%. Second
step was alkali base catalyzed transesterification.