Production of Fatty Acid Alkyl Esters from Waste Recycling Fats Using a Patented Chlorotrimethylsilane Method

BioDiesel (BD) is produced by transesterification of lipids (triglycerides) with an alkyl alcohol (generally methanol) in the presence of a catalyst. Glycerin is produced as byproduct of the reaction. By now the alkaline-catalyzed process is the most used. Nevertheless this method requires a substrate with a low acidity. In fact free fatty acids (FFA) are responsible for the formation of soaps and consequently emulsions. Many substrates coming from the recovery of waste oil, fried oil, animal fats from slaughter and generally no feeding purpose fats have a very high content in FFA. The application of the alkaline process requires further steps to reduce the acidity. On the contrary we report a new method [1, 2, 3] for BD production in which transesterification and esterification processes are performed at the same time. Moreover the new method allows an easy separation of the fatty acid alkyl esters phase from the glycerin. Chlorotrimethylsilane is applied as a "mediator" in methanol solution, but the reaction undergoes, with the same high efficiency, also with other alcohols like ethanol and n-butanol. The method works in homogeneous phase and mild reaction conditions and can be applied on many types of substrate, even those with high content in FFA coming from the waste recycling. At the end of the reaction, chlorotrimethylsilane is converted into an inert product, quantitatively recoverable to regenerate the starting catalyst, that can be recycled in the process. Applications of the new method will be presented. Bibliography 1. Brandi et al. italian patent 0001395587 2. Brandi et al. international patent WO2011023712A1 3. Salvini et al. (2012). RSC Advances, 2, 4864–4868.