More than 10 million tons of biodiesel fuel (BDF) have been produced in the world from the transesterification of vegetable oil with methanol by using acid catalysts (sulfuric acid, H₂SO₄), alkaline catalysts (sodium hydroxide, NaOH or potassium hydroxide, KOH), solid catalysts and enzymes. Unfortunately, the price of BDF is still more expensive than that of petro diesel fuel due to the lack of a suitable raw material oil. Here, we review the best selection of BDF production systems including raw materials, catalysts and production technologies. In addition, glycerol formed as a by-product needs to be converted to useful chemicals to reduce the amount of glycerol waste. With this in mind, we have also reviewed some recent studies on the utilization of glycerol.

A new, homogeneous method for producing biodiesel fuel (BDF), achieving a minimum emission of waste and a low consumption of energy, was developed by adding organic solvents such as acetone to a reaction mixture of oil and methanol with an alkaline catalyst. By adding acetone and a smaller amount of catalyst at room temperature, fatty acid methyl ester (FAME) was formed within 5 min with a quality satisfying the international BDF standards, even in the coexistent of water in the raw material. The difference in the kinetic data when using isopropyl alcohol (IPA) (all compounds are in a single phase) and acetone (all compounds except glycerin are in a single phase), shows that the retardation of FAME formation in the presence of glycerin product is not due to the reverse reaction but to the removal of methanol and KOH catalyst from the reaction phase by the precipitated glycerin produced during the final stages of the reaction.