Commercial refined palm oil was purchased from a local
department store in Thailand. 99.5% purity methanol, used for
transesterification, was purchased from Qrëc. The NaOH catalyst
purchased from Loba Chemie was ground and dissolved in methanol before use. Methyl heptadecanoate and heptane (internal standard and solvent for GC analysis, respectively) were high purity
chemicals from Sigma–Aldrich and were used as obtained