The methanolic acid solution for the esterification reaction was prepared with methanol min. 99.8% assay, AnalaR NORMAPUR from VWR International S.A.S. and sulfuric acid 95–97%, for analysis, EMSURE ISO from Merck. The methanolic solution prepared for the transesterification reaction used the same methanol but sodium hydroxide 97%, reagent grade, from Sigma–Aldrich.