As shown in Fig. 4 at high levels of methanol to oil molar ratio (>34:1) and temperature (>271 ◦C), decomposition of
FAME and reduction of yield occur.
By increasing the temperature above the reactant/product mixture critical temperature, decomposition of FAMEs decreases the yield of biodiesel [26].
The effect of temperature and time of the reaction is shown in Fig. 5.
The yield of the biodiesel increases with higher temperature up to around 271 ◦C, but in upper temperatures beyond 271 ◦C a gradually reduction occurs in the biodiesel yield.