Fatty acids methyl esters from vegetable oil by means of ultrasonic energy

• Published in: Ultrasonics sonochemistry Vol. 12; no. 5; pp. 367 - 372
• Main Authors: Stavarache, Carmen, Vinatoru, M., Nishimura, R., Maeda, Y.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2005; Elsevier
• Subjects: Alcohols - chemistry; Base catalysis; Biodiesel; Catalysis; Chemistry; Chromatography, Thin Layer; Esters; Exact sciences and technology; Fatty Acids - chemistry; Gas Chromatography-Mass Spectrometry; General and physical chemistry; Indicators and Reagents; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Plant Oils - chemistry; Plant Oils - radiation effects; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Transesterification; Ultrasonic chemistry; Ultrasonics; Ultrasound; Vegetable oil; Vegetable oil; Base catalysis; Transesterification; Ultrasound; Biodiesel; Energy; Sonochemistry; Fatty ester; Fatty acids
• ISSN: 1350-4177; 1873-2828
• DOI: 10.1016/j.ultsonch.2004.04.001

The transesterification of vegetable oil with short-chain alcohols, in the presence of base-catalyst, by means of low frequency ultrasound (28 and 40 kHz) in order to obtain biodiesel fuel was studied. By using ultrasounds the reaction time is much shorter (10–40 min) than for mechanical stirring. The quantity of required catalyst is 2 or 3 times lower. The molar ratio of alcohol/oil used is only 6:1. Normal chain alcohols react fast, while secondary and tertiary alcohols show some or no conversion after 60 min of reaction. Surprisingly, 40 kHz ultrasounds are much more effective in the reduction of the reaction time (10–20 min). Twenty eight kilohertz give slightly better yields (98–99%), but longer reaction time, while higher frequencies are not useful at all for the transesterification of fatty acids.