PRODUCTION OF ETHYL ESTER BIODIESEL FROM USED COOKING OIL WITH ETHANOL AND ITS QUICK GLYCEROL-BIODIESEL LAYER SEPARATION USING PURE GLYCEROL

Abstract

In this study, used cooking oil, ethanol and sodium hydroxide (NaOH) were used as raw material
and catalyst to produce biodiesel through transesterification reaction. The occurring emulsion from ethanol
acts as a surfactant in the reaction mixture make the separation of biodiesel from glycerol layer more difficult.
This problem solving was done by adding pure glycerol into the reaction mixture after complete reaction to
make quick layer separation between glycerol and biodiesel. The characterization of the produced biodiesel
was performed by proton nuclear magnetic resonance (1H-NMR) and gas chromatography (GC). The result
showed that the optimum condition for ethyl ester biodiesel production were 8:1 of ethanol to oil molar ratio,
0.75 %w/w of NaOH amount, 45 min of reaction time and 40 oC of reaction temperature. This condition gave
100% of fatty acid ethyl ester conversion that determined by 1H-NMR. The result on the optimum condition
for layer separation showed that the adding of 2.44% v/v of pure glycerol relation to the total volume of the
reaction mixture took 14.38 min for glycerol-biodiesel layer separation. In addition, ethyl ester biodiesel was
further analyzed its fuel properties followed ASTM biodiesel standard. The results showed the produced
biodiesel met well with the standard.