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Fig. 1 Alkali-catalyzed transesterification reaction (a–e). (a) Overall reaction. (b) Formation of
methoxide and protonated base catalyst. (c) Nucleophilic attack of methoxide on triglyceride to
form biodiesel and diglyceride. (d) Nucleophilic attack of the second molecule of methoxide on
diglyceride. (e) Nucleophilic attack of the third molecule of methoxide on monoglyceride
Z. Hussain et al.