Transesterification of waste oil to biodiesel using Brønsted acid ionic liquid as catalyst

Abstract

Brønsted acid ionic liquids were employed for the preparation of biodiesel using waste oil as the feedstock. It was found that IL 1–(3–sulfonic acid)propyl–3–methylimidazole hydrosulfate–[HO₃S-pmim]HSO₄ was an efficient catalyst for the reaction under the optimum conditions: n(oil):n(methanol) 1:12, waste oil 15.0 g, ionic liquid 2.0 g, reaction temperature 120 ^oC and reaction time 8 h, the yield of biodiesel was more than 96%. The reusability of the ionic liquid was also investigated. When the ionic liquid was repeatedly used for five times, the yield of product was still more than 93%. Therefore, an efficient and environmentally friendly catalyst was provided for the synthesis of biodiesel from waste oils.

KEY WORDS: Biodiesel, Ionic liquid, Waste oil, Catalysis

Bull. Chem. Soc. Ethiop. 2013, 27(2), 289-294.

DOI: http://dx.doi.org/10.4314/bcse.v27i2.14