Furanics: A novel diesel fuel with superior characteristics

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1 09FFL-0058 Furanics: A novel diesel fuel with superior characteristics Ed de Jong*, Gert-Jan Gruter Avantium, Zekeringstraat 29, 1014BV Amsterdam, The Netherlands Copyright 2009 SAE International ABSTRACT Avantium explores novel furan chemistry, focused on efficient and, compared to enzymatic bio-refinery processes, low cost conversion of C6 sugars (i.e. glucose, mannose, galactose and fructose) and C5 sugars (i.e. xylose and arabinose) into derivatives of the promising chemical key intermediate hydroxymethyl furfural (HMF (I), Fig. 1) in the presence of a solid acid catalyst. By applying advanced high-throughput R&D technology, a next generation biofuels, called Furanics was developed, which can be produced on the basis of sugars and other, non-food, carbohydrates. Furanics are products derived from carbohydrates such as sugars. Novel chemical, catalytic routes are developed to produce Furanics for a range of biofuel applications. Biofuels with advantageous qualities both over existing biofuels such as bioethanol and biodiesel as well as over traditional transportation fuels are the target. The energy density of ethoxymethylfurfural (EMF (IV), Fig. 1), a Furanics example) is 8.7 kwh/l. This is as good as regular gasoline (8.8 kwh/l), nearly as good diesel (9.7 kwh/l) and significantly higher than ethanol (6.1 kwh/l). This means that with a full tank of Furanics you can drive almost as far as with a full tank of traditional fuels. The high energy density of EMF and other Furanics, the fact that these HMF derivatives can now be obtained in high yields, in one or two steps, from hexose (sucrose & starch) or cheap raw materials which contain mixtures of pentoses and hexoses such as waste streams and lignocellulosics, and as these ethers are, in contrast to HMF, liquids at room temperature, make these very interesting biofuels. Using a regular Citroën Berlingo with a diesel engine, a range of blends of the novel biofuels with regular diesel were tested at Intertek, with different concentrations of the novel biofuel. The tests yielded positive results for all blends tested. The car exhaust analysis demonstrated a significant reduction of soot and sulphur emissions when using the novel biofuels compared to oil-based diesel and has not the cold weather problems of conventional biodiesel. The compounds have higher cetane numbers than regular diesel and have good oxidation stability. The very good results of the engine tests support the proof of principle of our next generation biofuels, and are a valuable milestone for our biofuels development program. It is our intention to develop a next generation of biofuels that are regarding fuel quality and costs superior to existing biofuels and that can compete with oil-based fuels. The reduction of soot in the car exhaust is encouraging, since fine particulate matter is considered a major disadvantage of using diesel today, because of its adverse environmental and health effects. DO NOT TYPE IN THIS FOOTER SECTION ON PAGE 1. TEXT WILL BE INSERTED INTO THIS AREA BY SAE STAFF UPON RECEIPT OF THE FINAL APPROVED MANUSCRIPT AT SAE INTERNATIONAL.

2 INTRODUCTION The use of biofuels in automotive engines has a history going back to the early 1900 s, but in Europe the production and use of these fuels has only been developing more seriously in the past decade. This is mainly the result of recent concerns about future energy security of supply and increased environmental concerns about the rise in Green House Gases caused by human activities. Biofuels are the only short term option for reducing the transportation emissions, as they have the potential of a closed CO2 balance. For bio-based fuels, three main biomass conversion routes are available: chemical, thermochemical and fermentative/enzymatic conversions. The preferred route depends among others on the type of biomass feedstock, availability, scale and desired product (1,2,3,4,5,6,7). Underneath the main options are clustered following the main conversion route: CHEMICAL CONVERSION: Direct conversion processes such as extraction of vegetable oils followed by esterification to biodiesel, possibly followed by further upgrading (NextBTL). Feedstocks are dedicated crops (rape seed, palm oil, Jatropha, algae) and waste streams (e.g. waste cooking oil) Liquid Phase Catalytic Processing (LPCP) is a promising biorefinery producing functionalised hydrocarbons from biomass-derived building blocks. THERMOCHEMICAL CONVERSION: Pyrolysis of wood and a wide range of other relatively dry heterogeneous biomass streams into pyrolysis oil further upgraded to a diesel equivalent Hydro Thermal Upgrading (HTU) of wet biomass to HTU oil derived diesel equivalent Liquid biofuels (methanol, ethanol, DME, Fischer- Tropsch liquids) from synthesis gas, which results from gasification of biomass. FERMENTATION / ENZYMATIC CONVERSION: debate if there is sufficient suitable agricultural land available (8). However, the conversion of biomass from different sources (including waste) will, in conjunction with other energy sources, help to make our societies less dependent on fossil oil. For that reason it is needed to work towards a technical, commercial and sustainable solution that will use the available biomass in the most efficient way. One of the main hurdles that need to be addressed is the issue of cost. An important approach to reduce costs is to apply a biorefinery approach towards biofuel production (9). Nature produces the vast amount of 170 billion metric tons (t) of biomass per year by photosynthesis, 75% of which can be assigned to the class of carbohydrates. Surprisingly, only 3-4% of these compounds are used by humans for food and non-food purposes (10). Biomass carbohydrates are the most abundant renewable resources available, and they are currently viewed as a feedstock for the Green Chemistry of the future (11,12,13,14). Two types of neutral sugars are present in biomass: hexoses (six-carbon sugars), of which glucose, mannose, galactose and fructose are the most common, and pentoses (five-carbon sugars), of which xylose and arabinose are the most common. There are two ways to selectively transform sugars into bioproducts: one is the fermentation process, and the other is chemical (catalytic) transformation. Glucose is present in carbohydrates such as sugars, starch, hemicellulose and cellulose. Cellulose and hemicellulose require chemical and physical pretreatment followed by enzymatic / chemical hydrolysis of the biopolymers into the constituting sugars. These sugars, in addition to sucrose (from sugarbeet or sugarcane) and starch, can be converted to ethanol by fermentation, but this conversion may not be the most economic and efficient process for the very large scale. In that sense, conventional bulk chemical or refinery type catalytic conversions are extremely fast, efficient and cheap and for that reason offer an interesting alternative for converting carbohydrates to other organic building blocks. In addition to that ethanol has several disadvantages such as the requirement of an energy-intensive distillation step and the problems associated with corrosivity and low energy density (leading to high transportation cost and less mileage per liter) which justifies an alternative approach. Fermentation of starch- and sugar-rich crops, mainly to ethanol and probably in the future also butanol. In the near future also lignocellulosic feedstocks can be used as feedstocks Anaerobic digestion of relatively unpersistent feedstocks into Biogas (a mixture of mainly CH 4 and CO 2 ) Not all of these biofuels will be commercially available on the short term and also these biofuels will not be able to replace oil-based fuels completely as there is a strong 2

3 MAIN SECTION Avantium is developing a new process to produce Furanics from carbohydrates. For many decades, HydroxyMethylFurfural (HMF; I) has been seen as the sleeping giant, a key substance between carbohydrate chemistry and mineral oil-based industrial chemistry, guarding the large application potential for furan based products (15,16). HMF can be produced from fructose by acid catalyzed elimination of 3 molecules of water. Many different conditions have been described to produce HMF (17,18,19,20,21,22,23) and references therein) and even though pilot-plant size processes have been operating, to date no commercial process for HMF has been established (24,25). As HMF is a solid at room temperature with very poor fuel blend properties, HMF cannot be used and has not been considered as a fuel or a fuel additive. However, despite the impressive array of useful HMF-derived intermediate chemicals in literature, HMF is still not produced on an industrial scale (8). The new Avantium process does not focus on HMF (which is not stable under the reaction conditions required for its formation) but on HMF derivatives such as furanic ethers, which are formed much faster than HMF decomposes (4,26,27). On the contrary, the production and further chemistry of furfural (II) is well developed, providing a host of versatile industrial chemicals by simple straightforward operations (28,29). Fig. 1: Range of furan intermediates resulting from dehydration of C6 and C5 sugars in different solvents. Explanation of the abbreviations: I = Hydroxymethyl furfural (HMF); II = Furfural; III = Methoxymethylfurfural (MMF); IV = Ethoxymethylfurfural (EMF); V = t- Buthoxymethlfurfrual (t-bmf). THE AVANTIUM APPROACH. Two earlier HMF commercialization attempts by Roquette Freres, France and Südzucker, Germany have made it to the pilot plant stage but not further. It can be concluded that the known methods for the synthesis of HMF with economic potential mostly start from fructose and typically do not give high yield, partly attributable to the instability of HMF under the acidic reaction conditions required for HMF formation (24,25). Low conversion routes in water and in biphasic solvent systems both have disadvantages and no commercial process could be developed using these approaches. In 2006 Avantium reported a new approach to prevent the non-selective HMF decompositions following its formation (26,27). It was found that the conversion of hexose-containing starting material, in particular fructose, glucose or sucrose in the presence of an acid catalyst in an alcohol as solvent can lead to the formation of the corresponding HMF-ether in good yield and selectivity. It was also found that HMF is more stable when the amount of water in the process is reduced (as water plays a role in the reaction of HMF to Levulinic Acid). Also, by forming the more stable 5-(alkoxymethyl)furfural ethers, the onward and undesired reaction towards levulinic acid type products and humins is blocked, thus leading to an efficient procedure for the conversion of fructose and/or glucose -containing material into HMF derivatives. As HMF is a solid at room temperature, it has never been considered as a fuel. However, when we were able to obtain liquid HMF ethers such as 5- (methoxymethyl)furfural (III), 5-(ethoxymethyl)furfural (IV) or 5-(tert-butoxymethyl)furfural (V) (Fig. 1) we were very interested to evaluate these ethers as a fuel. THE ENERGY DENSITY OF FURANICS. 5- ethoxymethylfurfural (EMF), the ether resulting from reaction of HMF with (bio)ethanol, can be determined. Starting with a calculated enthalpy of formation for EMF using increment tables of kj/mole, the reaction enthalpy can be calculated as kj/mol, leading due to the high EMF density to an energy density of 31.3 MJ/L. This is almost as good as regular gasoline and diesel and is significantly higher than ethanol (Fig. 2). This high energy density of EMF, the fact that these HMF derivatives can now be obtained in high yields, in one step, from very cheap hexose or hexose-containing starting materials such as sucrose and glucose, and as these ethers are, in contrast to HMF, liquids at room temperature, make these very interesting fuels or fuel additives. Due to the boiling points of the HMF ethers the initial target application area was diesel. Due to limited flexibility in European refineries to produce more diesel, the EU has to import 25 Mt diesel fuel from Russia to match the current annual 162 Mt diesel demands. On the other hand, the EU exports a surplus of Mt (19Mt goes to the US) of gasoline. This means that current efforts to produce renewable gasoline fuel components in Europe, such as bio-ethanol, will even lead to an increase of the European fossil gasoline surplus problem. However, the production of bio-diesel and other renewable diesel blend components will lead to a decrease of diesel imports from Russia, or replace fossil diesel production growth, and in the same time decrease the gasoline surplus in the EU. Some of the key characteristics of Furanics are presented in Table 1. 3

4 Table 1: Key characteristics of Furanics compared with regular diesel, aviation fuel (Jet A-1) and dimethylfuran (DMF). Aromatics (%) Flash point (ºC) Melting point (ºC) Boiling point (ºC) Density (15ºC, kg/m3) Net heat of combustion (MJ/L) FURAN ETHER SYNTHESIS. Upon investigation it was found that under the same set of conditions, the 5- (alkoxymethyl)furfural ether yields were decreasing when going to higher alcohols: methanol > ethanol > propanol > butanol > octanol. On the other hand, the blend properties of the resulting ethers was, not surprisingly, found to be increasing with increasing number of alcohol C-atoms (and with increased branching of the alcohol backbone), while also not surprising, the solubility of the hexose starting material was decreasing in alcoholic solvents with increasing the number of alcohol C-atoms. Mixtures of alcohols may also be employed but due to the differences in alcohol reactivities in this case the product mixture depends not only on the amount of the different alcohols in the feed but also on the conversion level. The acid catalyst can be a heterogeneous catalyst such as an acidic zeolite or a homogenous catalyst such as sulphuric acid. The advantage of a heterogeneous catalyst is that the reaction can be performed in a fixed bed continuous flow process. Energy Density (MJ/liter) cetane (diesel) octane (gasoline) EMF hexane pentane Diesel 11 (PAC) Varies butanol butane propane Jet A-1-47 range ethanol methane pyrolysis oil methanol ammonia liq. Hydrogen Fig. 2: The energy-density (MJ/l) of a wide range of (bio-)fuels. FUEL PROPERTIES. Although MMF (III) and EMF (IV) ethers of HMF are useful as fuel or fuel additives, it was found that these most easily obtained ethers have the DMF 100? Furanics > least attractive blending properties. For that reason, MMF and EMF were reacted with hydrogen in an alcohol solvent, using an acid catalyst system to form the corresponding di-ethers. In this way 2,5- bis(methoxymethyl)furan was obtained from the reduction of MMF in methanol and the corresponding 2,5-bis(ethoxymethyl)furan was obtained fro EMF in ethanol. Because of the second etherification step now also C5-sugars may be present in the carbohydrate feed (Fig. 3). C5-sugars will yield furfural (I) in the first dehydration step (which is not miscible with gasoline or diesel fuel). The second step will convert the furfural into ethers of furfuryl alcohol which show very good blend properties with conventional fuels. Mixtures of C5- and C6-sugars will yield fuel mixtures of 2- (alkoxymethyl)furan and 2,5-bis(alkoxymethyl)furan (Fig. 4). Besides the superior blend properties of the furan diethers, the feedstock used, the process applied and the yields obtained to produce the di-ether all have significant advantages over the alkoxymethylfurfural case. Fig. 3: Conversion of lignocellulosic feedstocks into furan intermediates. As the di-ether synthesis requires a separate etherification step, the initial integrated dehydration + etherification step does not require optimization to maximize ether yield but now allows optimization of HMF + ether yield (non etherified HMF obtained in the first step can be converted in the second step). The best alcohol for the first combined dehydration/etherification step is methanol, followed by ethanol. Both the ether yield and the carbohydrate (sugar) solubility are higher in methanol than for any other alcohol. Without the second etherification step, methanol cannot be used due to poor blend properties of the resulting MMF. By introducing a second etherification step, a lot of process and product flexibility is introduced. The MMF (or EMF) obtained from the first step can be converted to a di-ether in various alcohols. When methanol is used again, 2,5- bis(methoxymethyl)furan is obtained. With ethanol, the mixed 2-(ethoxymethyl)-5-(methoxymethyl)furan is obtained. In principle many 2-(alkoxymethyl)-furans and 2-(alkoxymethyl)-5-(methoxymethyl)furans can thus be obtained (Fig. 4). The main advantages of furanic ethers are the complete carbon efficiency and renewability of 4

5 furanic ethers because are bio-based and 100% renewable (when a biobased alcohol is used for the etherification). The sucrose and (hemi)-cellulose routes will enable the broadening of current biomass feedstock possibilities drastically. significantly. Additional engine testing with fully etherified furan compounds (VI, VII) are under way. Table 2: Exhaust characteristics of the Citroen Berlingo diesel engine under idle conditions. Fuel Time (min) SO 2 (normalized) NOx (ppm) Total particulate matter = Soot (mg/nm3) O 2 (%) CO 2 (%) Diesel % w/w RMF Fig. 4: Simultaneous conversion of furfural and alkoxymethylfurfural into furan mono- and di-ethers with methanol as solvent and etherification agent. 17% w/w RMF FUEL SOLUBILITY AND OXIDATION STABILITY. Fuel solubility is a primary concern for diesel fuel applications. Not all highly polar oxygenates have good solubility in the current commercial diesel fuels. Results show that 2,5-di(ethoxymethyl)furan and 5-(tertbutoxymethyl)-2- (ethoxymethyl)furan (V) are miscible in all blend ratio s with commercial diesel. In a comparative set of experiments it was shown that ethoxymethylfurfural (EMF) is completely miscible in a 5 vol% blend with commercial diesel, but that phase separation occurs with the 25 vol% and with the 40 vol% blends of EMF and diesel. Likewise, oxygenated fuel additives, certainly when containing an aldehyde functional group, often reduce the oxidation stability of the base diesel fuel. A 0.1 vol% blend of EMF with additive free diesel fuel was prepared at an outside laboratory for oxidation stability determination according to NF en ISO certified methods. Surprisingly, both the reference additive-free diesel and the 0.1 vol% EMF blend showed the same oxidation stability, indicating that the oxygenated EMF added to an additive free diesel base fuel does not decrease the oxidation stability of the blend relative to the pure base diesel. EMISSION ENGINE TESTING. In a D9B diesel engine of a Citroen Berlingo test car, comparative testing was performed with normal commercial diesel as a fuel and the same commercial diesel to which 25 vol. % 5-(tbutoxymethyl)furfural (t-bmf) was added, respectively. t- BMF is added as a liquid and does not yield any mixing or flocculation problems up to a 40 vol% blend ratio. The engine was run stationary with regular diesel initially, after which the fuel supply is switched to the 40 vol% tbmf-diesel blend. During stationary operation with the commercial diesel fuel and with the 25 vol% t-bmf blend, the following measurements were made: total particulate matter, volume, O 2, CO, CO 2, NO x (NO + NO 2 ) and total hydrocarbons (4). It was interesting to note that the total particulate matter (soot) emissions were reduced by 20%, sulphur was reduced by 25% (due to blending with sulphur-free biobased fuel, while the other exhaust components were not changed AVIATION FUELS. Aviation fuels consist of blends of over a thousand chemicals, primarily hydrocarbons (paraffins, olefins, naphthenes, and aromatics) as well as additives such as antioxidants and metal deactivators, and impurities. Principal components include n-octane and isooctane. Like other fuels, blends of Aviation fuel used in piston engined aircraft are often described by their octane rating. The net energy content for present day aviation fuels depends on their composition. Some typical values are: Avgas, 43.7 MJ/kg or 31.0 MJ/L; Wide-cut jet fuel, 43.5 MJ/kg or 33.2 MJ/L, and Kerosene type jet fuel, 43.8 MJ/kg or 35.1 MJ/L. For aviation fuel in particular, products of increased energy density, flash point, and low melting point are required. Ideally, these products should be based on biomass or biomass products. On the other hand, the preparation of these (aviation) biofuels should be economically feasible and energetically acceptable. Interestingly, some of the furanics products also show potential as aviation fuel and/or as fuel additive. Unlike the products resulting from mineral oil, biomass derived mono ethers and di-ethers (Fig. 1, Fig. 4) are very high in unsaturation. This enables the use of these compounds as a cheap hydrogen storage medium, without the challenging hydrogen release requirement! Both the hydrogen as well as the furan storage host can be used as an economic fuel. Moreover, mixtures of these biomass derived fuel components meet the requirements concerning flash point above 38 C and freeze point maximum of -47 C whilst providing a high energy density. In other words, the new fuel components are uniquely suitable for use as aviation fuel. Some examples of compounds with high potential are ringhydrogenated alkoxymethyltetrahydrofuran ethers such as 2,5-bis(alkoxymethyl)tetrahydrofuran (VI) and 2- (alkoxymethyl)tetrahydrofuran (VII). For the preparation of these fuel components, any 5-(alkoxymethyl)furan may be used, including mixtures of different 5- (alkoxymethyl)furans (Fig. 5). 5

6 accelerate process and product development and the involvement of raw material suppliers and fuel producers or end users for process and application know-how & future developments in early stage is essential. The availability of large quantities for testing is necessary and the process and application studies should be done in parallel. Fig. 5: The main types of ring-hydrogenated furan ethers. Explanation of the abbreviations: VI = 2,5- bis(alkoxymethyl)furan; VII = 5-(alkoxymethyl)furfural Thus, by converting a 5-(alkoxymethyl)furfural and 2,5- bis(alkoxymethyl)furan under ordinary ringhydrogenation conditions, fuel components were prepared. The preparation of ring-hydrogenated products does not necessarily require a third synthetic step. As the second etherification step also involves a hydrogenation (the aldehyde is in this step converted to an alcohol), the ring hydrogenation can also be combined with step 2. In that case, products from step 1, such as MMF and EMF can be directly converted to ring hydrogenated tetrahydrofuran ethers (Fig. 6). Also in this case, the starting material may also contain furfural in the feed. This furfural will be converted in the reaction with hydrogen and an alcohol to 2-(alkoxymethyl)furan and after ring-hydrogenation to 2- (alkoxymethyl)tetrahydrofuran. For (aviation) fuel each of these components, except the starting EMF and the hydroxymethyl alcohols, are useful. Fig. 6: Direct conversion of alkoxymethyl furfural into ring hydrogenated tetrahydrofuran ethers suitable for aviation fuels with methanol as etherification agent. The fully hydrogenated products are preferred, as their physical properties are best suited for aviation fuels and their energy density is the highest. Also, they mix better with fossil fuels. In such a case a selective hydrogenation catalyst will not be necessary. CONCLUSION AND FUTURE PLANS Furanics as diesel and aviation fuel have very good characteristics (economics, net heat of combustion/l, melting points, sulphur; no aromatics (ring hydrogenated products), very good blending properties and stability). High throughput methodologies are necessary to Very recently Avantium closed a financing round to fund further furanics research and development. Also several subsidies were granted to further develop both the monomer/polymer area as well as the renewable fuel application. Three high potential fuel candidate molecules were selected for scale up to at least several 100 liters each. This will allow for more extensive engine testing with an automotive partner in the second half of 2009 and Taking into consideration the ultra low sulfur content of conventional diesel (EN590:2009, 10ppm max), it could also be very interesting to see what is the influence of this new biofuel on the lubricating properties of the final blends. ACKNOWLEDGMENTS The authors like to thank the whole Amazon team for their invaluable contributions to this work. REFERENCES 1. Huber, G.W., Iborra, S., Corma, A. (2006) Synthesis of Transportation Fuels from Biomass: Chemistry, Catalysts, and Engineering. Chem. Rev., 106 (9): Huber, G.W., Dumesic, J.A. (2006) An overview of aqueous-phase catalytic processes for production of hydrogen and alkanes in a biorefinery. Catal. Today, 111 (1-2): Stöcker, M. (2008) Biofuels and Biomass-To-Liquid Fuels in the Biorefinery: Catalytic Conversion of Lignocellulosic Biomass using Porous Materials. Angew. Chem. Int. Ed., 47(48): Gruter, G.J., de Jong, E. (2009) Furanics: Novel fuel options from carbohydrates. Biofuels Technol., 1: Chheda, J.N., Dumesic, J.A. (2007) An overview of dehydration, aldol-condensation and hydrogenation processes for production of liquid alkanes from biomass-derived carbohydrates. Catal. Today, 123 (1-4): NSF (2008) Breaking the Chemical and Engineering Barriers to Lignocellulosic Biofuels: Next Generation Hydrocarbon Biorefineries. Ed. George W. Huber, University of Massachusetts Amherst. National Science Foundation. Chemical, Bioengineering, Environmental, and Transport Systems Division. Washington DC. 180 P. ( p2-08.pdf) 6

7 7. Lin, Y.-C., Huber, G. (2009) The critical role of heterogeneous catalysis in lignocellulosic biomass conversion. Energy Environ. Sci., 2: van Dam, J., Faaij, A.P.C., Lewandowski, I. Fischer, G. (2007) Biomass production potentials in Central and Eastern Europe under different scenarios. Biomass and Bioenergy 31: Kamm, B., Gruber, P.R., Kamm, M.(eds) (2006) Biorefineries Industrial Processes and Products, Status Quo and Future Directions, Vol. 1, 2. Wiley- VCH, Weinheim. 10. Roper, H. (2002) Renewable raw materials in Europe industrial utilisation of starch and sugar. Starch/Stärke. 54: Lichtenthaler, F.W., Peters, S. (2004) Carbohydrates as green raw materials for the chemical industry. C. R. Chimie, 7: Lange, J.-P. (2007) Lignocellulose conversion: An introduction to chemistry process and economics, in Catalysis for Renewables From Feedstock to Energy Production, (eds. G. Centi and R.A. van Santen), Weinheim, pp Werpy, T., Peterson, G. (2004) Top Added chemicals from biomass. Volume I: Results of screening potential candidates from sugars and synthesis gas. U.S. Department of Energy. ( 14. Gallezot, P. (2007) Process options for the catalytic conversion of renewables into bioproducts, in Catalysis for Renewables From Feedstock to Energy Production, (eds. G. Centi and R.A. van Santen), Weinheim, pp Lewkowski, J. (2001) Synthesis, Chemistry and applications of 5-hydroxymethylfurfural and its derivatives. Arkivoc, Binder, J.B., Raines, R.T. (2009) Simple Chemical Transformation of Lignocellulosic Biomass into Furans for Fuels and Chemicals. J. Am Chem. Soc., 131 (5): Moreau, C. (2006) Micro- and mesoporous catalysts for the transformation of carbohydrates, in Catalysis for chemical synthesis (ed E. Derouane), John and Wiley & Sons, Ltd. 18. Seri, K., Inoue, Y., Ishida, H. (2001) Catalytic Activity of Lanthanide(III) Ions for the Dehydration of Hexose to 5-Hydroxymethyl-2-furaldehyde in Water. Bull. Chem. Soc. Japan., 74 (6): Moreau, C., Finiels, A., Vanoye, L. (2006) Dehydration of fructose and sucrose into 5- hydroxymethylfurfural in the presence of 1-H-3- methyl imidazolium chloride acting both as solvent and catalyst. J. Mol. Catal. A: Chem., 253 (1-2): Carlini, C., Patrono, P., Galletti, A.M.R., Sbrana, G. (2004) Heterogeneous catalysts based on vanadyl phosphate for fructose dehydration to 5- hydroxymethyl-2-furaldehyde. Appl. Catal. A: Gen., 275 (1-2): Watanabe, M., Aizawa, Y., Iida, T., Aida, T.M., Levy, C., Sue, K., Inomata, H. (2005) Glucose reactions with acid and base catalysts in hot compressed water at 473 K. Carbohydr. Res. 340 (12): Bicker, M. Kaiser, D. Ott, L. and Vogel, H. (2005) Dehydration of d-fructose to hydroxymethylfurfural in sub- and supercritical fluids. J. Supercrit. Fluids 36 (2): Zhao, H., Holladay, J.E. Brown, H. and Zhang, Z.C. (2007) Metal chlorides in ionic liquid solvents convert sugars to 5-hydroxymethylfurfural. Science 316: Sanborn, A.J. (2008) US , Archer-Daniels- Midland Company, Decatur IL (US). Processes for the preparation and purification of hydroxymethylfuraldehyde and derivatives. 25. Rapp, K. (1991) EP02250 Südzucker Aktiengesellschaft, Mannheim, Germany. Process for the preparation of 5-hydroxymethylfurfural, including a crystalline product, using exclusively water as solvent. 26. Gruter, G.J.M. and Dautzenberg, F. (2007a) EP Method for the synthesis of 5- alkoxymethylfurfural ethers and their use. 27. Gruter, G.J.M. and Dautzenberg, F. (2007b) EP Method for the synthesis of 5- alkoxymethylfurfural esters and their use. 28. Zeitsch, K.J. (2000) The chemistry and technology of furfural and its many by-products, Sugar Series, vol. 13, Elsevier, The Netherlands. 29. Hoydonckx, H.E., van Rhijn, W.M., van Rhijn, W. de Vos, D.E., Jacobs, P.A.. (2007) Furfural and derivatives. Ullmann's Encyclopedia of Industrial Chemistry, CONTACT Ed de Jong (ed.dejong@avantium.com) VP Development Avantium ( Zekeringstraat 29, 1014BV Amsterdam, The Netherlands Tel: