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Reply to “Comment on ‘Heterogeneous Catalytic Deoxygenation of Stearic Acid for Production of Biodiesel’” Mathias Snåre and Dmitry Yu. Murzin* Åbo Akademi UniVersity, Åbo/Turku, Finland Sir: The authors are thankful to Professor Zhao for his comments about our work and for emphasizing the sensitive issue regarding the definition of biodiesel. Professor Zhao mentioned that the term “biodiesel has a specific, technical definition as a fuel comprised of monoalkyl esters of long-chain fatty acids derived from vegetable oils or animal fats”. The authors would like to take this opportunity to share their opinion on the matter regarding the definition of biodiesel. The definition of biodiesel is a complex issue. It was, in fact, in the middle of 20th century, in connection with the introduction of the transesterification diesel product, methyl fatty acid esters, that the term biodiesel was established.1 Moreover, as Professor Zhao noted, several international specifications have been established recently that define monoalkyl esters as biodiesel. Nonetheless, logically, biodiesel has been a widely used definition of a diesel fuel that originates from renewable raw materials, such as the transesterification, microemulsification, and pyrolysis of natural oils and fats,2,3 as well as wood-derived diesel fuel. We sincerely understand Professor Zhao’s concerns, in regard to misleading definitions; however, in this case, we feel that the scientific community and the general public should not limit themselves to associating biodiesel solely with fatty acid esters, sometimes even narrowed exclusively to methyl esters. Defini* To whom correspondence should be addressed. E-mail:
[email protected].
tions of general terms, such as diesel and gasoline, have been modified throughout the years, based on new technologies and improved final product qualities, despite the specific standards that have been established historically. For instance, recently, a second-generation biodiesel technology, NExBTL, was introduced in Finland by Neste Oil Oy; this technology produces diesel-like hydrocarbons that originate from natural oils and fats.4 The NExBTL biodiesel properties are similar (or are superior) to the best existing biodiesel or diesel fuel. The NExBTL product meets the requirements set by the European diesel fuel standard (EN590) and, furthermore, demonstrates appropriate fuel properties in the automotive and engine industries, according to World Wide Fuel Charter (WWFC) Category 4 fuel specifications. Based on the aforementioned statements, we feel that the definition of biodiesel should be used in a broader perspective. Literature Cited (1) Fukuda, H.; Kondo, A.; Noda, H. Biodiesel Fuel Production by Transesterification of Oils. J. Biosci. Bioeng. 2001, 91, 405-416. (2) Fangrui, M. A.; Milford, H. Biodiesel Production: A Review. Bioresour. Technol. 1999, 70, 1-15. (3) Pramanik, T.; Tripathi, S. Biodiesel: clean fuel of the future. Hydrocarbons Process. 2005, (February), 49-54. (4) Rantanen, L.; Linnaila R.; Aakko, P.; Harju, T. NExBTLsBiodiesel for the second generation. SAE Int. 2005, 01-3771.
IE061051T
10.1021/ie061051t CCC: $33.50 © 2006 American Chemical Society Published on Web 08/23/2006
