Moringa oleifera oil: A possible source of biodiesel q Umer Rashid a , Farooq Anwar a, * , Bryan R. Moser b , Gerhard Knothe b, * a Department of Chemistry, University of Agriculture, Faisalabad 38040, Pakistan b National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, 1815 North University Street, Peoria, IL 61604, USA article info Article history: Received 20 November 2007 Received in revised form 11 March 2008 Accepted 11 March 2008 Available online 12 May 2008 Keywords: Biodiesel Cetane number Fuel properties Moringa oleifera Transesterification abstract Biodiesel is an alternative to petroleum-based conventional diesel fuel and is defined as the mono-alkyl esters of vegetable oils and animal fats. Biodiesel has been prepared from numerous vegetable oils, such as canola (rapeseed), cottonseed, palm, peanut, soybean and sunflower oils as well as a variety of less common oils. In this work, Moringa oleifera oil is evaluated for the first time as potential feedstock for biodiesel. After acid pre-treatment to reduce the acid value of the M. oleifera oil, biodiesel was obtained by a standard transesterification procedure with methanol and an alkali catalyst at 60 °C and alcohol/oil ratio of 6:1. M. oleifera oil has a high content of oleic acid (>70%) with saturated fatty acids comprising most of the remaining fatty acid profile. As a result, the methyl esters (biodiesel) obtained from this oil exhibit a high cetane number of approximately 67, one of the highest found for a biodiesel fuel. Other fuel properties of biodiesel derived from M. oleifera such as cloud point, kinematic viscosity and oxidative stability were also determined and are discussed in light of biodiesel standards such as ASTM D6751 and EN 14214. The 1 H NMR spectrum of M. oleifera methyl esters is reported. Overall, M. oleifera oil appears to be an acceptable feedstock for biodiesel. Published by Elsevier Ltd. 1. Introduction Biodiesel is defined as the fatty acid alkyl esters of vegetable oils, animal fats or waste oils. It is a technically competitive and environmentally friendly alternative to conventional petrodiesel fuel for use in compression–ignition (diesel) engines (Knothe et al., 2005; Mittelbach and Remschmidt, 2004). Biodiesel is biode- gradable, renewable, non-toxic, possesses inherent lubricity, a rel- atively high flash point, and reduces most regulated exhaust emissions in comparison to petrodiesel. The use of biodiesel re- duces the dependence on imported fossil fuels, which continue to decrease in availability and affordability. Vegetable oils for biodiesel production vary considerably with location according to climate and feedstock availability. Generally, the most abundant vegetable oil in a particular region is the most common feedstock. Thus, rapeseed and sunflower oils are predom- inantly used in Europe; palm oil predominates in tropical coun- tries, and soybean oil and animal fats in the USA (Knothe et al., 2005; Mittelbach and Remschmidt, 2004). However, biodiesel pro- duction from conventional sources (soybean, rapeseed, palm, etc.) increasingly has placed strain on food production, price and avail- ability (Torrey, 2007). Therefore, the search for additional regional biodiesel feedstocks is an important objective. Some recent exam- ples, studies of biodiesel from less common or unconventional oils include tobacco (Usta, 2005), Pongamia (Karmee and Chadha, 2005), Jatropha (Foidl et al., 1996) and rubber seed (Ikwuagwu et al., 2000; Ramadhas et al., 2005) oils. The Moringaceae is a single-genus family of oilseed trees with 14 known species. Of these, Moringa oleifera, which ranges in height from 5 to 10 m, is the most widely known and utilized (Morton, 1991; Sengupta and Gupta, 1970). M. oleifera, indigenous to sub-Himalayan regions of northwest India, Africa, Arabia, South- east Asia, the Pacific and Caribbean Islands and South America, is now distributed in the Philippines, Cambodia and Central and North America (Morton, 1991). In Pakistan, M. oleifera is widely grown in the Punjab plains, Sindh, Baluchistan, and in the North- western Frontier Province (Qaiser, 1973). It thrives best in a tropi- cal insular climate and is plentiful near the sandy beds of rivers and streams (Council of Scientific and Industrial Research, 1962). The fast growing, drought-tolerant M. oleifera can tolerate poor soil, a wide rainfall range (25 to 300+ cm per year), and soil pH from 5.0 to 9.0 (Palada and Changl, 2003). When fully mature, dried seeds are round or triangular shaped, and the kernel is surrounded by a lightly wooded shell with three papery wings (Council of Scientific and Industrial Research, 1962; Sengupta and Gupta, 1970; Qaiser, 1973). M. oleifera seeds contain between 33 and 41% w/w of vegetable oil (Sengupta and Gupta, 1970). Several 0960-8524/$ - see front matter Published by Elsevier Ltd. doi:10.1016/j.biortech.2008.03.066 q Disclaimer: Product names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable. * Corresponding authors. E-mail addresses: fqanwar@yahoo.com (F. Anwar), gerhard.knothe@ars.usda.gov (G. Knothe). Bioresource Technology 99 (2008) 8175–8179 Contents lists available at ScienceDirect Bioresource Technology journal homepage: www.elsevier.com/locate/biortech 9854