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The transesterification of rice bran oil with methanol has been studied in the presence of sulfuric acid (H2SO4), tin chloride dihydrate (SnCl2·2H2O), tin 2-ethylhexanoate (Sn(C8H15O2)2), dibutyl tin oxide ((C4H9)2SnO), and dibutyl tin dilaurate ((C4H9)2Sn(C12H23O2)2), known commercially as DBTDL. Through the comparative analysis among the catalysts, we observed that the complex DBTDL presented the best performance, with a yield of 68.9% in 4 h using molar ratio 400:100:1 (methanol:oil:catalyst). These results evidenced the viability of the use of metallic compounds as catalysts in the obtainment of biodiesel, an interesting alternative to basic and acid catalysis.

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A Concise Synthesis of (S)-(+)-5,6-Dihydro-2H-Pyran-2-one via Hydrozirconation-Carbonylation-Demetalation of O-Benzyl (S)-(-)-4-pentyn-2-ol.--(DUPONT, J.; DONATO, A. J.; Tetrahedron: Asymmetry 9 (1998) 6, 949-954; Inst. Quim., Univ. Fed. Rio Grande do Sul,