CHEMICAL ENGINEERING TRANSACTIONS VOL. 56, 2017 A publication of The Italian Association of Chemical Engineering Online at www.aidic.it/cet Guest Editors: Jiří Jaromír Klemeš, Peng Yen Liew, Wai Shin Ho, Jeng Shiun Lim Copyright © 2017, AIDIC Servizi S.r.l., ISBN 978-88-95608-47-1; ISSN 2283-9216 Conversion of Oil Palm Biomass to Ethyl Levulinate via Ionic Liquids Yong Wei Tiong a , Chiew Lin Yap* ,a , Suyin Gan b , Winnie Soo Ping Yap a a Faculty of Science, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia b Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia Chiew-Lin.Yap@nottingham.edu.my Biomass is a potential renewable feedstock that can be used as a replacement for fossil resources. A variety of high end chemicals have been produced from biomass including ethyl levulinate, which is a viable biofuel for diesel engines. In this study, the capability of three types of imidazolium based ionic liquids (ILs) catalysts, i.e., 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]), 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM][HSO4]) and 1-methylimidazolium hydrogen sulfate ([HMIM][HSO4]) to convert oil palm empty fruit bunch (OPEFB) and oil palm mesocarp fiber (OPMF) biomass to ethyl levulinate were compared. The procedure entailed a sequential reaction of depolymerisation of biomass at 160 °C for 3 hours, followed by an esterification at 90 °C for 12 h in excess ethanol, with ILs-to-biomass ratio of 5 : 1 by weight and 20 wt% water. It was demonstrated that only the last two acidic [HSO4] - counteranion based ILs are able to convert the biomass to ethyl levulinate. Mono-alkylated ILs, [HMIM][HSO4], consistently gave a higher efficiency than multi-alkylated ILs, [BMIM][HSO4], for both OPEFB and OPMF biomass conversions, with ethyl levulinate yields of 11.61 % and 13.54 %, and the process efficiencies of 39.26 % and 50.79 %. OPMF appears to be a slightly more efficient feedstock in ethyl levulinate production than OPEFB. This indicates the performance of ILs was dependent upon the character of their cation side chain, seeing that both ILs used have the same acidic [HSO4] - counteranion. The experimental results suggested that [HMIM][HSO4] has the potential to be used in ethyl levulinate production from sustainable biomass feedstocks under mild operating conditions. 1. Introduction The continuous rise in energy requirements due to the increase of population and rapid industrial growth has been a global concern for centuries. Although a shift to shale gas and away from other fossil fuels is increasingly plausible, the adverse environmental impact associated to these energies remains unresolved. Extensive researches are being carried out to search alternative resources which are cleaner, inexpensive and renewable. Conversion of biomass to biofuel (Elumalai et al., 2016) is a particularly attractive approach, as it transforms waste into useful product. Malaysia has a rich oil palm industry which generates tremendous amount of biomass. Oil palm empty fruit bunch (OPEFB) and oil palm mesocarp fiber (OPMF) contribute a significant amount of 22 % and 13.5 % of the mass of each fruit bunch (FFB) (Aditiya et al., 2016). Cellulose is the main composition of oil palm biomass and serves the major substrate for the catalytic conversion to levulinic acid (Rackemann and Doherty, 2011). Levulinic acid can be further converted to biofuel, i.e., ethyl levulinate, via the esterification with ethanol, as illustrated in Figure 1. Ethyl levulinate contains ~14 mol% oxygen, having similar properties to the biodiesel fatty acid ethyl esters (FAEEs). It provides a cleaner burning with high lubricity, flashpoint stability, reduced sulfur content and improved viscosity in regular diesel engines. It also serves as viable bio-derived petroleum diesel fuel oxygenate additive (Windom et al., 2011). DOI: 10.3303/CET1756171 Please cite this article as: Tiong Y.W., Yap C.L., Gan S., Yap W.S.P., 2017, Conversion of oil palm biomass to ethyl levulinate via ionic liquids, Chemical Engineering Transactions, 56, 1021-1026 DOI:10.3303/CET1756171 1021