Results and discussion
PSME is produced from transesterification of palm stearin with methanol and using NaOCH3 as catalyst. Properties of PSME were presented in Table 1.
The results in Table 1 show properties of PSME which meet Thai Biodiesel Standard [7]. PSME sample has little amount of Diglyceride and Triglyceride, which cannot be detected with the resolution of the equipment. However, white sediment was found in PSME, which was stored for a long period. The white sediment can melt upon heating to a temperature of 40-50 oC but re-appear upon cooling under ambient condition as a solid phase at the bottom again.