Synthesis of Biodiesel via Deoxygenation of Stearic Acid over Supported Pd/C Catalyst Siswati Lestari Æ Irina Simakova Æ Anton Tokarev Æ Pa ¨ivi Ma ¨ki-Arvela Æ Kari Era ¨nen Æ Dmitry Yu Murzin Received: 18 February 2008 / Accepted: 29 February 2008 / Published online: 18 March 2008 Ó Springer Science+Business Media, LLC 2008 Abstract High catalytic activity was achieved in the deoxygenation of stearic acid in dodecane in a temperature range of 270–300 °C under 17 bar helium over palladium on nanocomposite carbon Sibunit. Besides n-heptadecane, which was obtained previously in this reaction with palla- dium on activated carbon, n-pentadecane was also formed in significant amounts. Keywords Deoxygenation Á Fatty acid 1 Introduction The potential capacity of bio-oil for replacing the use of oil-based energy demand has been evaluated as follows: If all the farming land would be used for oil and fat pro- duction, its hypothetical yield would be 1.5 9 10 12 kg per harvest being equal to 52 9 10 18 J per harvest. The energy obtained per harvest is then 34.7 MJ/kg, which is about 80% of the diesel energy value (43.3 MJ/kg) covering only 15% of the total annual energy consumption [1, 2]. These considerations lead to the conclusion that although tech- nologies for renewable energy production should be developed but they cannot alone covers the current energy demand. Additionally it should be pointed out that ethically more sustainable method would be to use as a raw material for biodiesel production non-edible oil-yielding plants, such as mahua, karanja and jatropha [3–5]. Biodiesel has been traditionally defined as fatty acid (methyl) esters. The second generation of biodiesel consists of diesel-like hydrocarbons, which are industrially pro- duced [6]. Synthesis of biodiesel has been under intensive research efforts in the recent years [7–12], since the annual energy consumption is expected to grow. There exist sev- eral other technologies to prepare biodiesel, like pyrolysis [13] and transesterification [14]. A novel technology to prepare biodiesel is to use metal supported catalysts and deoxygenate fatty acids and their derivatives [7]. The main advantage of this technology compared to the transesteri- fication method is that less by-products, like glycerol, are formed. Catalytic deoxygenation of fatty acids, esters and tri- glycerides has been studied intensively during the recent years [7–12]. Catalytic deoxygenation has been successfully performed under inert gas or hydrogen in a semibatch reactor in temperature and pressure ranges of 300–360 °C and from 6 to 40 bar, respectively [8–10]. Since the main gaseous products are carbon dioxide and carbon monoxide the use of semibatch reactor helps to maintain the catalytic activity high due to purging out the formed product gases. The cat- alyst screening study revealed that Pd and Pt supported on carbon catalysts are the most active and selective for this reaction. Typically the reaction has been studied in the presence of a solvent, dodecane and the main liquid phase product has been n-heptadecane. Furthermore a minor amount of unsaturated C17 compounds has been formed and the yield of the main product has been 95% at the complete conversion of stearic acid [9]. Besides applicability of a S. Lestari ARC Centre of Excellence for Functional Nanomaterials, University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia I. Simakova Boreskov Institute of Catalysis, Novosibirisk, Russia A. Tokarev Á P. Ma ¨ki-Arvela Á K. Era ¨nen Á D. Y. Murzin (&) Process Chemistry Centre, A ˚ bo Akademi University, 20500 Turku/A ˚ bo, Finland e-mail: dmurzin@abo.fi 123 Catal Lett (2008) 122:247–251 DOI 10.1007/s10562-008-9457-x