Catalysis Today 175 (2011) 435–441 Contents lists available at ScienceDirect Catalysis Today jou rn al h om epage: www.elsevier.com/locate/cattod Etherification of 5-hydroxymethyl-2-furfural (HMF) with ethanol to biodiesel components using mesoporous solid acidic catalysts P. Lanzafame a,∗ , D.M. Temi a , S. Perathoner a , G. Centi a , A. Macario b , A. Aloise b , G. Giordano b a Department of Industrial Chemistry and Engineering of Materials and CASPE-INSTM, University of Messina, 98166 Messina, Italy b Department of Chemical Engineering and Materials, University of Calabria, Rende, 87030 Cosenza, Italy a r t i c l e i n f o Article history: Received 31 October 2010 Received in revised form 27 April 2011 Accepted 16 May 2011 Available online 16 June 2011 Keywords: HMF Biodiesel components Acid sites Mesoporous catalysts Ethanol Etherification a b s t r a c t The etherification of 5-hydroxymethyl-2-furfural (HMF) with ethanol is studied over a series of meso- porous silica catalysts (Al-MCM-41 materials with different Si/Al ratio, and zirconia or sulfated zirconia supported over SBA-15) and compared with the behavior of H 2 SO 4 and Amberlyst ® 15. The observed reaction products were 5-(ethoxymethyl)furan-2-carbaldehyde (EMF), 1,1-dietoxy ethane (DE) and ethyl 4-oxopentanoate (EOP). The selectivity to EMF and EOP is closely related to the presence of Lewis and/or Brønsted acidity on the catalyst, while the formation of DE is probably related to defect sites. The latter, being less reactive, catalyze the side reaction to DE only when strong Lewis and/or Brønsted acid sites are absent. Catalysts with only a strong Brønsted acidity react selectively to form EOP. When strong Lewis acid sites are present in the catalyst, e.g. by introducing ZrO 2 in SBA-15 or when extra-framework isolated Al 3+ sites are present in the mesoporous channels, a high selectivity to EMF was observed. The results indicate that EMF, DE or EOP can be obtained selectively by direct reaction of HMF with bioethanol by tuning the acidity of the catalyst. EMF is a value biodiesel component, but the results also evidence the possibility to obtain selectively EOP in a one-step reaction, opening interesting perspectives to produce valeric biofuels by subsequent selective hydrogenation. © 2011 Elsevier B.V. All rights reserved. 1. Introduction 5-Hydroxymethylfurfural (HMF) is formed as the main prod- uct in the acid-catalyzed conversion of ligno-cellulosic biowastes (residues of the agro-food production, municipal wastes, etc.) in industrial processes such as the Biofine ® , but is also formed as byproduct in some pretreatments processes of cellulosic raw mate- rials and should be removed due to its inhibition effect on the enzymatic fermentation. In addition, it is also the main reac- tion product in the novel conversion processes of ligno-cellulosic materials (straw, for example) using ionic liquids [1], an area of increasing interest. The valorization of HMF is thus of key relevance for the development of biorefineries [2], because it may be considered an excellent platform molecule which can be converted to energy products (2,5-dimethylfuran, an octane booster), monomers for high-value polymers (2,5-carboxyfuran and 2,5-hydroxymethylfuran) and valuable intermediates for fine chemistry. While few recent papers discussed some of these reactions [3], no literature results have been reported on the relevant option to produce compounds for biodiesel, apart the general indication of ∗ Corresponding author. E-mail address: planzafame@ingegneria.unime.it (P. Lanzafame). the interest by Avantium, a spin-off company of Shell, in developing this kind of reaction compounds as part of the general class of new bio-based chemicals called “furanics” [4,5]. However, they have not given indications on the type of catalysts necessary and the reaction conditions, and thus essentially no literature data are available on this reaction. The production of 2 nd generation biodiesel from ligno-cellulosic sources is a commercial and strategic interest for Europe. Indeed about 60% of the new light cars are based on diesel engine but Europe needs to import both diesel and vegetable oils to produce 1 st generation biodiesel (via transesterification of vegetable oils). We report here for the first time the comparison of a series of mesoporous solid acid catalysts in the etherification of HMF by ethanol to produce a components for biodiesel and other valuable intermediate. The observed reaction products are 5- (ethoxymethyl)furan-2-carbaldehyde (EMF), 1,1-dietoxy ethane (DE) and ethyl 4-oxopentanoate (EOP). As reported by Avantium [4], EMF is an excellent additive for diesel, with high energy den- sity of 8.7 kWh/L, similar to regular gasoline (8.8 kWh/L), nearly as good as diesel (9.7 kWh/L) and significantly higher than ethanol (6.1 kWh/L). Blends with regular diesel yielded positive results with a significant reduction of soot (fine particulates), and a reduc- tion of the SO x emissions. EOP, after hydrogenation, gives valeric ester, a biofuel developed by researchers at Shell Global Solutions, although through a different route: via levulinic acid, converted to 0920-5861/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.cattod.2011.05.008