Review article The production of biodiesel from vegetable oils by ethanolysis: Current state and perspectives Olivera S. Stamenkovic ´, Ana V. Velic ˇkovic ´ , Vlada B. Veljkovic ´ ⇑ Faculty of Technology, University of Niš, 16000 Leskovac, Bulevar Oslobodjenja 124, Serbia article info Article history: Received 30 November 2010 Received in revised form 10 June 2011 Accepted 13 June 2011 Available online 14 July 2011 Keywords: Biodiesel Catalyst Ethanolysis Transesterification abstract At present, the homogeneous base-catalyzed methanolysis reaction of vegetable oils is a most often used process for the industrial biodiesel production. The toxicity of methanol, the risk of the methanol vapor explosion and the possibility of the ethanol production from biorenewable resources have contributed to the development of a vegetable oil ethanolysis process for the biodiesel production. In the reaction of vegetable oils and ethanol in the presence of a catalyst, completely agricultural fuels consisted of fatty acid ethyl esters (FAEE) are obtained having physico-chemical properties similar to those of the appropri- ate methyl esters and diesel fuel. The ethanolysis reaction of various oily feedstocks has been widely studied to optimize the reaction conditions and to develop new catalytic systems and processes based on chemical and biological catalysts, as well as the development of non-catalytic processes. Most researches investigate the application of homogeneous base catalysts. This paper studies the review of vegetable oil ethanolysis investigations for the biodiesel production done so far. The goals of the paper are to present the development of FAEE synthesis by catalytic and non-catalytic processes, their advan- tages and disadvantages, the influence of some operating and reaction conditions on the process rate and ethyl esters yield, the kinetics models describing the ethanolysis process rate, the process optimization and the possibilities for improving the FAEE synthesis process. Ó 2011 Elsevier Ltd. All rights reserved. Contents 1. Introduction ........................................................................................................ 3141 2. Vegetable oil ethanolysis .............................................................................................. 3142 3. Chemically catalyzed vegetable oil ethanolysis ............................................................................ 3143 3.1. Homogeneously catalyzed vegetable oil ethanolysis .................................................................. 3143 3.2. Heterogeneously catalyzed vegetable oil ethanolysis .................................................................. 3146 4. Enzyme-catalyzed vegetable oil ethanolysis............................................................................... 3147 5. Non-catalyzed vegetable oil ethanolysis .................................................................................. 3149 6. The optimization of vegetable oil ethanolysis reaction conditions ............................................................. 3150 7. Kinetics of vegetable oil ethanolysis ..................................................................................... 3150 8. The possibilities for improving the ethanolysis reaction ..................................................................... 3151 9. Conclusions ......................................................................................................... 3153 Acknowledgments ................................................................................................... 3153 References ......................................................................................................... 3153 1. Introduction A decrease in the world oil supplies and the instability of great exporting regions caused the increase of the price for both fossil fuel and its derivates. Apart from that, high quantities of CO 2 , which is the basic cause of global warming, are emitted by fossil fuel combustion. For ecological and economic reasons, the obtain- ing of biofuels from biomass is seriously considered with the pos- sibility to integrate these technologies into the existing industrial plants. EU strategy is that each Member State ensures the share of en- ergy from renewable sources in all forms of transport, which 0016-2361/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.fuel.2011.06.049 ⇑ Corresponding author. Tel.: +381 16 247 203; fax: +381 16 242 859. E-mail address: veljkovicvb@yahoo.com (V.B. Veljkovic ´). Fuel 90 (2011) 3141–3155 Contents lists available at ScienceDirect Fuel journal homepage: www.elsevier.com/locate/fuel