Ethanolysis of Refined Soybean Oil Assisted by Sodium and Potassium Hydroxides

• Published in: Journal of the American Oil Chemists' Society Vol. 84; no. 4; pp. 385 - 392
• Main Authors: Kucek, Karla T, César-Oliveira, Maria Aparecida F, Wilhelm, Helena M, Ramos, Luiz P
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.04.2007; Springer-Verlag; Springer; Springer Nature B.V
• Subjects: Adsorption; Biodiesel; Biological and medical sciences; Crude oil; Developing countries; Diesel fuels; ethanol; Ethanolysis; Ethyl esters; Experimental design; Fat industries; Fatty acids; Food industries; Fundamental and applied biological sciences. Psychology; hydrolysis; Hydroxides; Ion exchange; KOH; LDCs; Magnesol; NaOH; oil refining; Optimization; potassium hydroxide; Sodium hydroxide; Soybean oil; Soybeans; Specifications; Standard deviation; Sulfuric acid; Sustainable development; Transesterification; KOH; NaOH; Vegetable oil; Transesterification; Ethanolysis; Edible oil; Biodiesel; Optimization; Sodium hydroxide; Ethyl esters; Oils and fats industry; Ester; Magnesol; Adsorption; Alternative motor fuel; Refined oil; Soybean oil
• ISSN: 0003-021X; 1558-9331
• DOI: 10.1007/s11746-007-1048-2

The ethanolysis of refined soybean oil was investigated through a 2³ experimental design that was carried out under the following levels: ethanol:oil molar ratios (MR) of 6:1 and 12:1, NaOH concentrations of 0.3 and 1.0 wt% in relation to the oil mass, and reaction temperatures of 30 and 70 °C. The ethanol:oil MR and the alkali concentration had an almost equivalent influence on the reaction yield, whereas the influence of increased reaction temperatures was very limited and higher catalyst concentrations led to greater yield losses due to the formation of soap. Ethyl ester yields of 97.2% were obtained at 70 °C, MR of 12:1 and 0.3 wt% NaOH. Replacement of 0.3 wt% NaOH by 1.0 wt% KOH under the same reaction conditions led to lower ester yields. Likewise the former, KOH provided the maximum ester yield (95.6%) at the highest molar ratio (12:1), with the reaction temperature having little influence on the catalyst performance. Ester yields beyond 98% were only achieved when a second ethanolysis stage was included in the process. In this regard, the application of 2 wt% Magnesol® after the first ethanolysis stage eliminated the need for water washing prior to the second ethanolysis stage and helped to generate a final product with less contaminating unreacted glycerides.