The single factor experimentswere performed to evaluate the effects
of different conditions on esterification rate of FFA with glycerol: catalyst
loading varied from 0% to 0.7 wt.% (based on the weight of WCO)
with an interval of 0.1 wt.%, the molar ratio of glycerol to FFA varied
from0.8:1 to 1.7:1with an interval of 0.1:1, reaction temperature varied
from170 °C to 210 °Cwith an interval of 10 °C, and reaction time varied
from 1 h to 5 h with an interval of 1 h. The stirring rate was kept
constant (300 rpm) for all experiments.