Production of standard biodiesel from soybean oil: A single-reaction process using sodium hydroxide as catalyst

Biodiesel fuel is comprised of fatty acid methyl esters, currently made from vegetable oils using basic catalysts. With current technology, the oils must be reacted two or three times with methanol, in the presence of sodium methoxide to make products which meet the ASTM and European standards for the chemically bound glycerol content. It is also believed that sodium hydroxide can never be used as the catalyst because it causes soap formation, which lowers the yield and makes product isolation difficult.; This study describes laboratory methods for producing standard biodiesel from low acid-number vegetable oils in single-step reactions without distillation of the products. Either sodium hydroxide or methoxide are used as the catalyst. These methods rely on the use of oxolane as co-solvent to manipulate phase behavior and accelerate the esterification reaction. Variations in the catalyst concentration and alcohol/oil molar ratios have also been investigated.