5-Hydroxymethylfurfural (HMF) As a Building Block Platform.Pdf
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View Online Green Chemistry Dynamic Article Links Cite this: Green Chem., 2011, 13, 754 www.rsc.org/greenchem CRITICAL REVIEW 5-Hydroxymethylfurfural (HMF) as a building block platform: Biological properties, synthesis and synthetic applications Andreia A. Rosatella,a Svilen P. Simeonov,a Raquel F. M. Fradea and Carlos A. M. Afonso*a,b Received 5th August 2010, Accepted 15th December 2010 DOI: 10.1039/c0gc00401d The biorefinery is an important approach for the current needs of energy and chemical building blocks for a diverse range of applications, that gradually may replace current dependence on fossil-fuel resources. Among other primary renewable building blocks, 5-hydroxymethylfurfural (HMF) is considered an important intermediate due to its rich chemistry and potential availability from carbohydrates such as fructose, glucose, sucrose, cellulose and inulin. In recent years, considerable efforts have been made on the transformation of carbohydrates into HMF. In this critical review we provide an overview of the effects of HMF on microorganisms and humans, HMF production and functional group transformations of HMF to relevant target molecules by taking advantage of the primary hydroxyl, aldehyde and furan functionalities. 1 Introduction tion should be controlled to avoid formation of oligosaccharides and to prevent monosaccharides from reacting at the high The main source of functionalized carbon skeletons for the temperatures used.4 fine chemical industry, as well as for thermal and energy In contrast to cellulose, hemicellulose is a polymer formed by transportation, is still based on the fossil-fuel reservoir. However, different sugar units such as glucose, galactose, mannose, xylose the increasing price of oil will create new demand for molecules and arabinose, and it does not form crystalline regions, making it from renewable sources, and it seems likely that biorefineries will Downloaded by University of Oxford on 06 April 2011 more amenable to hydrolysis. Additionally, the rate of hydration 1 play a more significant role in this respect in the near future. depends on the sugar type, and decreases following the order The commercial production of wood sugars for ethanol Published on 28 February 2011 http://pubs.rsc.org | doi:10.1039/C0GC00401D xylose > mannose > glucose. Consequently, hemicellulose is production was first considered at the beginning of the 20th hydrolysed faster than cellulose. Whereas dehydration of hexoses 2 century. Lignocellulose, a very abundant material, comprises produces HMF, pentoses can lead to production of furfural.4 important polymers (cellulose, hemicellulose and lignin), of HMF is very useful not only as intermediate for the produc- which cellulose and hemicellulose in particular are of high tion of the biofuel dimethylfuran (DMF) and other molecules, importance, since they are formed from monomers of glucose but also for important molecules such as levulinic acid, (or other types of sugar in the case of hemicellulose), and they 2,5-furandicarboxylic acid (FDA), 2,5-diformylfuran (DFF), can be used as a carbon source in fermentation processes for the dihydroxymethylfuran and 5-hydroxy-4-keto-2-pentenoic acid production of ethanol. (Scheme 1). There are already a considerable range of chemical building blocks derived from renewable resources.3 One of these, 5- hydroxymethylfurfural (HMF), plays an important role, because it can be obtained not only from fructose but also (more recently) from glucose via isomerisation to fructose, as well as directly from cellulose. Cellulose is formed by anhydro-D-glucopyranose units linked by b-1→4-glycosidic bonds, and thus hydrolytic degradation is necessary to release the sugar monomers. Hydrolytic degrada- aCQFM, Centro de Qu´ımica-F´ısica Molecular and IN–Institute of Nanosciences and Nanotechnology, Instituto Superior Tecnico,´ 1049-001, Lisboa, Portugal. E-mail: [email protected]; Fax: + 35 1218464455/7; Tel: +35 218419785 biMed.UL, Faculdade de Farmacia´ da Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisboa, Portugal. E-mail: [email protected]; Fax: +35 1-21-7946476 Scheme 1 754 | Green Chem., 2011, 13, 754–793 This journal is © The Royal Society of Chemistry 2011 View Online HMF was first reported at the end of the 19th century, when HMF, for instance, during heating of milk, which has a high Dull et al.5 described its synthesis by heating inulin with oxalic concentration of lactose and lysine-rich proteins.23 Under acidic acid solution under pressure. In the same year, Kiermayer6 conditions, lactulosyl-lysine can suffer 1,2-enolization via 3- reported a similar procedure for HMF synthesis, but starting deoxyosulose to form bound HMF. However, isomerisation from sugar cane. In the subsequent years, several preparation and degradation of lactose (the Lobry de Bruyn–van Ekenstein methods were reported using homogeneous and heterogeneous transformation) also accounts for the formation of HMF. acid catalysis, both in aqueous media.7 This topic was first re- Quantification of bound HMF can be used to assess the extent of viewed in 1951 by Newth et al.,8 and since then several important the Maillard reaction in foods. Morales et al. have removed the reviews have been published, including one by Moye et al.9 on free lactose from milk samples and quantified HMF released synthetic methods and industrial applications of HMF. Later, from oxalic acid degradation of lactulosyl-lysine compounds, Harris10 described the dehydration reactions of carbohydrates in using reversed-phase HPLC. This study demonstrated that this acidic and basic conditions, including their mechanisms. In 1981 method can be used to determine the extent of the Maillard two reviews where published, one covering HMF manufacture,11 reaction; however, they also showed that this reaction is a minor and other focusing on HMF chemistry.12 In 1990 and 1991, route for sugar degradation. Other techniques, such as the 2- two important reviews were published by Kuster13 and Cottier thiobarbituric acid (TBA) method, widely applied in dairies, et al.14 respectively, describing the manufacture of HMF. More can also be used to quantify HMF, but it is less suitable since recently, Lewkowski15 and Moreau et al.16 have reviewed the other aldehydes can take part in the reaction.24 synthesis and chemistry of HMF. Corma et al.3a dedicated a Many other studies have been published, but HPLC seems to chapter to the synthesis of HMF in an outstanding review be the chosen method for HMF determination.25 Solubilisation of biomass transformations. Woodley et al.17 also summarized of the ground food sample in water and use of trichloroacetic some processses for the synthesis of HMF, and Zhang et al.18 acid (as a clarifying agent), was used to eliminate interference connected biomass transformations with imidazolium salts, by during HPLC determination of HMF in cookies.25b HMF including the synthesis of HMF with ionic liquids as solvents. determination has also been used as a parameter to evaluate Some of these reviews are comprehensive, while others just heat effects during manufacture of cereal products.26 Ram´ırez– mention HMF chemistry,19 but this area has been progressing Jimenez´ et al. have reported formation of HMF during browning very fast, and over 90 articles have been reported in scientific of sliced bread, and increasing amounts were detected with journals in 2010.20 increasing heating time (14.8 mg kg-1 and 2024.8 mg kg-1 with 5 In this critical review we provide an overview of the biological or 60 min toasting time, respectively).26c Fallico et al. have also properties of HMF, recent developments in the preparation of reported the effect of the temperature in the HMF formation HMF from carbohydrates, and synthetic transformations. during the roasting of hazelnuts, and they also studied the effect of the oil in this mechanism. Defatted crushed hazelnuts produced less HMF during roasting (2.2 mg kg-1 at 150 ◦C 2 Formation of HMF during baking ◦ Downloaded by University of Oxford on 06 April 2011 for 60 min) than crushed hazelnuts (8.0 mg kg-1 at 150 Cfor In the bakery industry, the formation of dough starts with a 60 min), and addition of 10% water to the defatted crushed Published on 28 February 2011 http://pubs.rsc.org | doi:10.1039/C0GC00401D mixture of flour, water, yeast and salt, which after fermentation hazelnuts led to an increase of HMF of approximately 32%. is subjected to high temperatures. During this baking process, Additionally, increasing the temperature to 175 ◦C produced the dough undergoes physical and chemical changes. The an increase in HMF concentration, as expected (66.5 mg kg-1 temperature leads to the evaporation of water and the formation for crushed hazelnuts and 17.9 mg kg-1 for defatted crushed of compounds that contribute to flavour and browning. These hazelnuts), even when toasted for 30 min.27 Furthermore, studies products result from Maillard reactions and caramelization. The have also demonstrated that formation of HMF decreases with first consists of a reaction between the carbonyl group of the the increase of humidity, and that fructose is more efficiently sugar and the amino group of an amino acid, and generally degraded in this furfural derivative than glucose.28 occurs at high temperatures (>50 ◦C) and acidic pH (4–7), and is favoured in foods with a high protein and carbohydrate content and intermediate moisture content.21 Caramelization is 3 Biological properties the oxidation of sugar, and needs more drastic conditions, such 3.1 Effects of HMF on the growth of microorganisms as temperatures above 120 ◦C and more extreme pH (<3or>9) and a low amount of water.21 The use of hemicellulose in fermentation as a carbon source, These reactions are frequent in bakery products, but also in and the consequent generation of HMF, has created a demand other foods subjected to high temperatures during processing. for HMF-resistant microorganism strains (Table 1).