Ultrasound assisted catalysis for biodiesel production

The EU directive 2009/28/EC has set the targets of achieving in each member State, by 2020, a minimum share of 10% of energy consumption in transport sector from renewable sources. In this context special consideration is paid to the production of biofuels. The most recent challenges concerning biodiesel production (BD) deal with the use of non food-grade oilseeds and their standardization to make them suitable to be transformed into methyl esters (BD) through transesterification [1, 2]. In fact raw oils contain high acidities which, besides giving saponification problems during the BD production are also regulated by the European normative on BD (EN14214) [3].The aim of the present work is to conceive an efficient method able to perform both the standardization and the transformation into BD of raw oils. In this work heterogeneously acid-catalyzed esterification of free fatty acids (FFA) and homogeneously basic-catalysed transesterification are investigated in raw tobacco and rapeseed oils along with the use of ultrasound (US). The most outstanding result of this study concerns how US are able to increase reactions yields because of the occurrence of the acoustic cavitation in the liquid reaction medium as well as the occurrence of the surface cavitation which generates mechanical effects on the catalyst’s surface.