PROCESS FOR SYNTHESIZING 5-HYDROXYMETHYLFURFURAL

Abstract

The invention relates to a process for the production of a mixture of 5-hydroxymethylfurfural and glucose from a feedstock containing fructose in the presence of at least one polar aprotic solvent and of at least one dehydration catalyst, in which process the reaction temperature is less than 90° C.

Claims

1. A process for the production of 5-hydroxymethylfurfural comprising bringing a feedstock containing free fructose, taken as a mixture with any saccharide or polysaccharide entity, i.e. any polysaccharide feedstock containing one or more non-fructoside units and one or more fructoside units, into contact with at least one dehydration catalyst chosen from homogeneous or heterogeneous and organic or inorganic Brønsted acids, in a polar aprotic solvent having a boiling point of less than 300° C., said process being carried out at a temperature of between 50 and 90° C.

2. The process as claimed in claim 1, carried out at a temperature of between 60 and 85° C., preferably between 60 and 80° C. and preferably between 65 and 75° C.

3. The process as claimed in claim 1, in which the dehydration catalyst has a pKa in DMSO of between 0 and 5.0.

4. The process as claimed in claim 1, in which the polar aprotic solvent has a boiling point of less than 250° C., preferably of less than 200° C.

5. The process as claimed in claim 1, in which the conversion of the fructoside fraction into 5-HMF is greater than or equal to 70% and the conversion of the non-fructoside fraction is less than or equal to 20%.

6. The process as claimed in claim 1, in which the feedstock is introduced in an initial concentration by weight of fructoside unit of greater than or equal to 7% by weight, preferably of between 8% and 30% by weight, with respect to the total weight of solvent.

7. The process as claimed in claim 1, in which the feedstock is introduced at a solvent/feedstock ratio by weight of between 0.1 and 200.

8. The process as claimed in claim 1, in which the feedstock is chosen from sucrose or a mixture of glucose and fructose.

9. The process as claimed in claim 1, in which the polar aprotic solvent is chosen from butan-2-one, acetone, acetic anhydride, N,N,N′,N′-tetramethylurea, benzonitrile, acetonitrile, methyl ethyl ketone, propionitrile, hexamethylphosphoramide, nitrobenzene, nitromethane, N,N-dimethylformamide, N,N-dimethylacetamide, sulfolane, N-methylpyrrolidone, dimethyl sulfoxide, propylene carbonate and γ-valerolactone.

10. The process as claimed in claim 1, in which the polar aprotic solvent is dimethyl sulfoxide.

11. The process as claimed in claim 1, in which the homogeneous organic Brønsted acid catalysts are chosen from organic acids of general formulae R′COOH, R′SO.sub.2H, R′SO.sub.3H, (R′SO.sub.2)NH, (R′O).sub.2PO.sub.2H, R′OH, in which R′ is chosen from the following groups: alkyls, preferably comprising between 1 and 15 carbon atoms, which are or are not substituted by at least one substituent chosen from a hydroxyl, an amine, a nitro, a halogen, preferably fluorine, and an alkyl halide, alkenyls, which are or are not substituted by at least one group chosen from a hydroxyl, an amine, a nitro, an oxo, a halogen, preferably fluorine, and an alkyl halide, aryls, preferably comprising between 5 and 15 carbon atoms, which are or are not substituted by a substituent chosen from a hydroxyl, an amine, a nitro, an oxo, a halogen, preferably fluorine, and an alkyl halide, heteroaryls, preferably comprising between 4 and 15 carbon atoms, which are or are not substituted by a substituent chosen from a hydroxyl, an amine, a nitro, an oxo, a halogen, preferably fluorine, and an alkyl halide.

12. The process as claimed in claim 1, in which the homogeneous inorganic Brønsted catalysts are chosen from HF, HCl, HBr, HI, H.sub.2SO.sub.3, H.sub.2SO.sub.4, H.sub.3PO.sub.2, H.sub.3PO.sub.4, HNO.sub.2, HNO.sub.3, H.sub.2WO.sub.4, H.sub.4SiW.sub.12O.sub.40, H.sub.3PW.sub.12O.sub.40, (NH.sub.4).sub.6(W.sub.12O.sub.40).xH.sub.2O, H.sub.4SiMo.sub.12O.sub.40, H.sub.3PMo.sub.12O.sub.40, (NH.sub.4).sub.6Mo.sub.7O.sub.24.xH.sub.2O, H.sub.2MoO.sub.4, HReO.sub.4, H.sub.2CrO.sub.4, H.sub.2SnO.sub.3, H.sub.4SiO.sub.4, H.sub.3BO.sub.3, HClO.sub.4, HBF.sub.4, HSbF.sub.5, HPF.sub.6, H.sub.2FO.sub.3P, CISO.sub.3H, FSO.sub.3H, HN(SO.sub.2F).sub.2 and HIO.sub.3.

13. The process as claimed in claim 1, in which the homogeneous organic Brønsted acid catalysts are chosen from formic acid, acetic acid, trifluoroacetic acid, lactic acid, levulinic acid, 2,5-furandicarboxylic acid, methanesulfinic acid, methanesulfonic acid, trifluoromethanesulfonic acid, bis(trifluoromethanesulfonyl)amine, benzoic acid, para-toluenesulfonic acid, 4-biphenylsulfonic acid, diphenyl phosphate and 1,1′-bi naphthyl-2,2′-diyl hydrogen phosphate.

14. The process as claimed in claim 1, in which the dehydration catalyst(s) are introduced in a solvent/catalyst(s) ratio by weight of between 20 and 10 000, in which the weight of solvent corresponds to the total weight of solvent employed in the process.

Description

DETAILED DESCRIPTION OF THE INVENTION

Feedstock

[0044] The saccharide feedstock employed in the process according to the invention comprises either a feedstock containing free fructose, taken as a mixture with any saccharide or polysaccharide entity, or any polysaccharide feedstock containing one or more non-fructoside units and one or more fructoside units which can release fructose by one or more hydrolysis stages. Preferentially, the feedstock treated in the process is sucrose or a mixture of glucose and fructose.

[0045] Advantageously, the fructose-containing saccharide feedstock comprises fructose in the monomeric, oligomeric or polymeric form.

[0046] Feedstock containing free (or monomeric) fructose taken as a mixture with any saccharide entity denotes, for example, syrups of High-Fructose Corn Syrup type containing fructose and glucose in different proportions (glucose/fructose in ratios by weight or molar ratios of 58/42, 45/55, 10/90, for example). Syrup is understood to mean a solution of sugar in water having a concentration of at least 30 wt %, preferably at least 50 wt %, preferably at least 70 wt %.

[0047] Polysaccharide feedstock containing one or more non-fructoside units and one or more fructoside units which can release fructose by one or more hydrolysis stages denotes the oligosaccharides and polysaccharides in which at least one monosaccharide unit is fructose. Feedstocks such as sucrose, kestose, fructans, oligofructans or inulin are denoted, for example.

[0048] Advantageously, the polysaccharide feedstocks listed above are capable of releasing monomeric fructose by hydrolysis, it being possible for said fructose produced to be converted into 5-HMF in the process according to the invention.

[0049] Oligosaccharide more particularly denotes a carbohydrate having the empirical formula (C.sub.6mH.sub.10m+2O.sub.5m+1)(C.sub.5nH.sub.8n+2O.sub.4n+1), where m and n are integers, the sum of which is between 2 and 6. The monosaccharide units making up said oligosaccharide are identical or different and at least one unit of formula (C.sub.6mH.sub.10m+2O.sub.5m+1) is fructose. By extension, polysaccharide denotes a carbohydrate having the empirical formula (C.sub.6mH.sub.10m+2O.sub.5m+1)(C.sub.5nH.sub.8n+2O.sub.4n+1), where m and n are integers, the sum of which is greater than or equal to 7.

[0050] Advantageously, the feedstock contains a mixture of fructoside and glucoside units so that the process according to the invention makes it possible to obtain a mixture of 5-HMF and glucose. For example, in the case where the feedstock is sucrose, the process according to the invention can make it possible to produce an equimolar mixture of 5-HMF and glucose. Likewise, in the case where the feedstock is High-Fructose Corn Syrup, the process according to the invention makes it possible to produce a mixture of 5-HMF and glucose, the stoichiometry of which depends on the composition of the starting High-Fructose Corn Syrup.

[0051] The feedstock is advantageously introduced into the process at a solvent/feedstock ratio by weight of between 0.1 and 200.0, preferably between 0.3 and 100.0 and more preferentially between 1.0 and 50.0.

Solvents

[0052] The process according to the invention is carried out in the presence of at least one polar aprotic solvent having a boiling point of less than 300° C., preferably of less than 250° C., preferably of less than 200° C. The polar aprotic solvent is advantageously chosen from butan-2-one, acetone, acetic anhydride, N,N,N′,N′-tetramethylurea, benzonitrile, acetonitrile, methyl ethyl ketone, propionitrile, hexamethylphosphoramide, nitrobenzene, nitromethane, N,N-dim ethylformamide, N,N-dimethylacetamide, sulfolane, N-methylpyrrolidone, dimethyl sulfoxide, propylene carbonate and γ-valerolactone. Preferably, the polar aprotic solvent is chosen from acetone, hexamethylphosphoramide, N,N-dimethylformamide, sulfolane, N-methylpyrrolidone, dimethyl sulfoxide, propylene carbonate and γ-valerolactone. Preferably, the polar aprotic solvent is dimethyl sulfoxide (DMSO).

Dehydration Catalyst

[0053] According to the invention, the process is carried out in the presence of at least one dehydration catalyst chosen from homogeneous or heterogeneous and organic or inorganic Brønsted acids capable of catalyzing the dehydration of fructose to give 5-hydroxymethylfurfural.

[0054] In one embodiment, at least one dehydration catalyst is chosen from homogeneous or heterogeneous organic Brønsted acids capable of catalyzing the dehydration of fructose to give 5-hydroxymethylfurfural.

[0055] Preferably, the homogeneous or heterogeneous organic Brønsted acids have a pKa in DMSO of between 0 and 5.0, preferably between 0.5 and 4.0 and in a preferred way between 1.0 and 3.0. Said pKa values are as defined in the paper by F G Bordwell et al. (J. Am. Chem. Soc., 1991, 113, 8398-8401).

[0056] Preferably, the homogeneous organic Brønsted acid catalysts are chosen from organic acids of general formulae R′COOH, R′SO.sub.2H, R′SO.sub.3H, (R′SO.sub.2)NH, (R′O).sub.2PO.sub.2H, R′OH, in which R′ is chosen from the following groups: [0057] alkyls, preferably comprising between 1 and 15 carbon atoms, preferably between 1 and 10 and preferably between 1 and 6, which are or are not substituted by at least one substituent chosen from a hydroxyl, an amine, a nitro, a halogen, preferably fluorine, and an alkyl halide, [0058] alkenyls, which are or are not substituted by at least one group chosen from a hydroxyl, an amine, a nitro, an oxo, a halogen, preferably fluorine, and an alkyl halide, [0059] aryls comprising between 5 and 15 carbon atoms and preferably between 6 and 12 carbon atoms, which are or are not substituted by a substituent chosen from a hydroxyl, an amine, a nitro, an oxo, a halogen, preferably fluorine, and an alkyl halide, [0060] heteroaryls comprising between 4 and 15 carbon atoms and preferably between 4 and 12 carbon atoms, which are or are not substituted by a substituent chosen from a hydroxyl, an acid, an amine, a nitro, an oxo, a halogen, preferably fluorine, and an alkyl halide.

[0061] When the catalysts of organic Brønsted acid type are chosen from organic acids of general formula R′—COOH, R′ can also be a hydrogen.

[0062] Preferably, the organic Brønsted acids are chosen from formic acid, acetic acid, trifluoroacetic acid, lactic acid, levulinic acid, 2,5-furandicarboxylic acid, methanesulfinic acid, methanesulfonic acid, trifluoromethanesulfonic acid, bis(trifluoromethanesulfonyl)amine, benzoic acid, para-toluenesulfonic acid, 4-biphenylsulfonic acid, diphenyl phosphate and 1,1′-binaphthyl-2,2′-diyl hydrogen phosphate. Very preferably, the homogeneous organic Brønsted acid catalyst is chosen from methanesulfonic acid (CH.sub.3SO.sub.3H) and trifluoromethanesulfonic acid (CF.sub.3SO.sub.3H).

[0063] The heterogeneous organic Brønsted acid catalysts are chosen from ion-exchange resins, in particular from sulfonic acid resins based on a copolymer preferably of sulfonated styrene/divinylbenzene or on a sulfonated tetrafluoroethylene copolymer (such as, for example, the following commercial resins: Amberlyst® 15, 16, 35 or 36, Dowex® 50 WX2, WX4 or WX8, Nafion® PFSA NR-40 or NR-50, or Aquivion® PFSA PW 66, 87 or 98), charcoals functionalized by sulfonic and/or carboxylic groups, or silicas functionalized by sulfonic and/or carboxylic groups. Preferably, the heterogeneous organic Brønsted acid catalyst is chosen from sulfonic acid resins.

[0064] In one embodiment, at least one dehydration catalyst is chosen from homogeneous inorganic Brønsted acids capable of catalyzing the dehydration of fructose to give 5-hydroxymethylfurfural.

[0065] Preferably, the homogeneous inorganic Brønsted catalysts are chosen from HF, HCl, HBr, HI, H.sub.2SO.sub.3, H.sub.2SO.sub.4, H.sub.3PO.sub.2, H.sub.3PO.sub.4, HNO.sub.2, HNO.sub.3, H.sub.2WO.sub.4, H.sub.4SiW.sub.12O.sub.40, H.sub.3PW.sub.12O.sub.40, (NH.sub.4).sub.6(N.sub.12O.sub.40).xH.sub.2O, H.sub.4SiMo.sub.12O.sub.40, H.sub.3PMo.sub.12O.sub.40, (NH.sub.4).sub.6Mo.sub.7O.sub.24.xH.sub.2O, H.sub.2MoO.sub.4, HReO.sub.4, H.sub.2CrO.sub.4, H.sub.2SnO.sub.3, H.sub.4SiO.sub.4, H.sub.3BO.sub.3, HClO.sub.4, HBF.sub.4, HSbF.sub.5, HPF.sub.6, H.sub.2FO.sub.3P, CISO.sub.3H, FSO.sub.3H, HN(SO.sub.2F).sub.2 and HIO.sub.3. Preferably, the inorganic Brønsted acids are chosen from HCl, HBr, HI, H.sub.2SO.sub.4, H.sub.3PO.sub.4 or HNO.sub.3. Very preferably, the inorganic Brønsted acid is HCl.

[0066] The dehydration catalyst(s) are introduced into the reaction mixture in a solvent/catalyst(s) ratio by weight of between 20 and 10 000, preferably between 40 and 2000, preferably between 100 and 1000, in which the weight of solvent corresponds to the total weight of solvent employed in the process.

Implementation of the Process

[0067] Said process is carried out at a temperature of between 50 and 90° C., preferably between 60 and 85° C., preferably between 60 and 80° C., preferably between 65 and 75° C., very preferably at 70° C., and preferably at a pressure of between 0.0001 and 8.0 MPa, preferably between 0.001 and 5.0 MPa and in a preferred way between 0.01 and 3.0 MPa.

[0068] Without being committed to any theory, the implementation of the process according to the invention at temperatures of less than 90° C. makes it possible to selectively convert the fructoside fraction of the feedstock while retaining the unconverted or weakly converted non-fructoside fraction (for example glucoside fraction).

[0069] Preferably, the process makes it possible to achieve conversions of the fructoside fraction into 5-HMF of greater than or equal to 70%, preferably of greater than or equal to 75%, in a preferred way of greater than or equal to 80%. Said conversions of the fructoside fraction are accompanied by a conversion of the non-fructoside fraction of less than or equal to 20%, preferably of less than or equal to 16%, preferably of between 0% and 15%, preferably between 0.1% and 12.0%, in a way between 0.5% and 10.0%, very preferably between 0.5% and 5.0%.

[0070] Preferably, the process is carried out for a period of time of between 15 and 300 minutes (min), preferably between 20 and 260 min, preferably between 30 and 240 min, preferably between 30 and 200 min, preferably between 35 and 150 min and very preferably between 45 and 120 min.

[0071] The feeding of the saccharide feedstock into the reaction mixture can be carried out according to several forms of introduction of said feedstock.

[0072] Preferably, the feedstock is introduced into the process into at an initial concentration by weight of fructoside unit of greater than 7% by weight, preferably of between 8% and 30% by weight (wt), with respect to the total weight of solvent, preferably between 9% and 26% by weight, preferably between 12% and 22% by weight.

[0073] In a first embodiment, the feedstock is introduced into the reaction mixture in the solid form, optionally using a suitable device which makes it possible to control the flow rate of feedstock.

[0074] Nonlimitingly, this device can be an endless screw or a pneumatic system for the transportation of solid particles. Nonlimitingly, this embodiment is preferred for a feedstock of oligosaccharide or polysaccharide type.

[0075] The introduction of a feedstock in the solid form corresponding to sucrose or to kestose, from which fructose is released by hydrolysis, is one possibility. Said introduction can be carried out on one or more occasions, sequentially or else continuously.

[0076] In a second embodiment, the feedstock is introduced in the liquid form into the reaction medium in solution in a solvent, known as additional solvent, using a pump which makes it possible to control the flow rate for introduction of the solution containing the feedstock. This embodiment is particularly well suited to a feedstock of monosaccharide type, indeed even oligosaccharide type, which can be dissolved in the additional solvent at high concentrations.

[0077] Preferably, the gradual introduction of a feedstock corresponding to a fructose and glucose syrup (of High-Fructose Corn Syrup type) via a pump is carried out. Said introduction can be carried out on one or more occasions, sequentially or else continuously.

Additional Solvent

[0078] In a specific embodiment, the process also comprises the use of at least one additional solvent chosen from polar aprotic or protic solvents. Said additional solvent can in particular make possible the dissolution of the feedstock before it is brought into contact with the polar aprotic solvent and the dehydration catalyst according to the invention.

[0079] Preferably, said additional solvent is chosen from butan-2-one, acetone, acetic anhydride, N,N,N′,N′-tetramethylurea, benzonitrile, acetonitrile, methyl ethyl ketone, propionitrile, hexamethylphosphoramide, nitrobenzene, nitromethane, N,N-dimethylformamide, N,N-dimethylacetamide, sulfolane, N-methylpyrrolidone, dimethyl sulfoxide, propylene carbonate, γ-valerolactone, water, methanol, ethanol, formic acid and acetic acid.

[0080] Preferably, the additional solvent chosen from polar aprotic or protic solvents is acetone, hexamethylphosphoramide, N,N-dimethylformamide, sulfolane, N-methylpyrrolidone, dimethyl sulfoxide, propylene carbonate, γ-valerolactone, water, methanol and ethanol, preferably from N,N-dimethylformamide, sulfolane, N-methylpyrrolidone, dimethyl sulfoxide, water and methanol, and very preferably the additional solvent is chosen from water and dimethyl sulfoxide.

[0081] In a third embodiment, the additional solvent used corresponds to all or to a fraction of the reaction mixture. In this scenario, the additional solvent thus contains at least the polar aprotic solvent, at least one dehydration catalyst employed in the process and optionally at least a fraction of unconverted feedstock of the 5-HMF produced. This embodiment advantageously makes it possible to gradually increase the amount of 5-HMF without increasing the volume of additional solvent. This embodiment of the process for the production of 5-HMF is carried out non-continuously.

[0082] In a continuous implementation of the process according to the invention, the weight hourly space velocity (flow rate of feedstock by weight/weight of catalysts) is between 0.01 h.sup.−1 and 5.0 h.sup.−1 and preferably between 0.02 h.sup.−1 and 2.0 h.sup.−1.

[0083] Whatever the embodiment of the process employed, the water contained in the reaction mixture is preferably removed by any method known to a person skilled in the art, preferably continuously, in order to maintain a water content of less than 30.0 wt %, with respect to the total weight of solvent, preferably of less than 20.0 wt %, preferably of less than 15.0 wt % and very preferably of less than 10.0 wt %.

[0084] Advantageously, the implementation of the process for the production of 5-HMF and glucose makes it possible to obtain a good conversion of the fructose involved, and also an excellent selectivity in favor of 5-HMF, while limiting the conversion of the glucose.

The Products Obtained and their Method of Analysis

[0085] The product selectively obtained by the conversion process according to the invention is 5-hydroxymethylfurfural (5-HMF) and glucose. On conclusion of the reaction carried out in the process according to the invention, the reaction medium is analyzed by high performance liquid chromatography (HPLC) in order to determine the conversion of the fructoside fraction of the feedstock and the content of unconverted glucose and of 5-HMF produced in the presence of an internal standard in order to quantify the undesired products (also known as byproducts), such as levulinic acid, formic acid and any coproduct containing sugars, such as humins. The humins are quantified by difference in carbon balance with the carbon initially introduced.

Examples

[0086] In the examples below, the glucose, fructose and sucrose used as feedstock are commercially available and are used without further purification.

[0087] The hydrochloric acid is used in the form of a concentrated 1.0M (mol/l) commercial solution in diethyl ether. The methanesulfonic acid, denoted MSA in the examples, is commercially available and is used without further purification.

[0088] The dimethyl sulfoxide, denoted DMSO in the examples, used as polar aprotic solvent, is commercially available and is used without further purification.

[0089] The concentrations by weight of the constituents of the reaction mixtures are determined by high performance liquid chromatography (HPLC). Aliquots are withdrawn from the reaction mixture at regular intervals in order to evaluate the composition thereof by HPLC. In the examples below in which the feedstock is sucrose, the degree of conversion of the sucrose is 100%, the sucrose being converted into a mixture of glucose, fructose and their reaction products.

[0090] It is understood that one mole of sucrose consists of one mole of glucoside units and one mole of fructoside units.

[0091] The degree of conversion of the fructose (ConvFRu) is defined as the ratio of the molar concentration of converted fructose to the molar concentration of fructoside units present in the initial feedstock, expressed as %.

[0092] The glucose yield (YieldGLu) is defined as the ratio of the molar concentration of glucose measured in the samples to the molar concentration of glucoside units present in the initial feedstock, expressed as %.

[0093] The 5-HMF yield (YieldHMF) is defined as the ratio of the molar concentration of 5-HMF measured in the samples to the molar concentration of fructoside units only present in the initial feedstock, expressed as %.

Example 1 (in Accordance) Conversion of a 1:1 Glucose/Fructose Mixture into 5-HMF and Glucose in the Presence of Hydrochloric Acid at 70° C.

[0094] Hydrochloric acid (1.0M (mol/1) in diethyl ether (Et.sub.2O)) (5.0 mmol) is added to a solution of glucose (4.5 g, 25.0 mmol) and fructose (4.5 g, 25.0 mmol) in DMSO (41.0 g). The initial fructose concentration by weight is 9.0 wt %. The initial glucose concentration by weight is 9.0 wt %. The catalyst/(glucose+fructose) molar ratio is 0.100. The reaction medium is stirred at 70° C. for 4 hours. The yields at different reaction times are reported in table 1.

TABLE-US-00001 TABLE 1 Time 30 min 60 min 120 min 240 min Conv.sub.FRU 87.8 96.5 100 100 Yield.sub.GLU 92.2 90.7 88.1 81.5 Yield.sub.HMF 60.1 70.4 75.1 77.4

Example 2 (in Accordance) Conversion of Sucrose into 5-HMF and Glucose in the Presence of Hydrochloric Acid at 70° C.

[0095] Hydrochloric acid (1.0M in Et.sub.2O) (2.65 mmol) is added to a solution of sucrose (9.0 g, 26.3 mmol) in DMSO (41.0 g). The initial sucrose concentration by weight is 18.0 wt %. The catalyst/sucrose molar ratio is 0.100. The reaction medium is stirred at 70° C. for 4 hours. The yields at different reaction times are reported in table 2.

TABLE-US-00002 TABLE 2 Time 30 min 60 min 120 min 240 min Conv.sub.FRU 91.4 97.4 100 100 Yield.sub.GLU 92.6 92.4 88.2 82.5 Yield.sub.HMF 61.2 69.3 73.0 73.6

Example 3 (in Accordance) Conversion of Sucrose into 5-HMF and Glucose in the Presence of Methanesulfonic Acid at 70° C.

[0096] Methanesulfonic acid (2.60 mmol) is added to a solution of sucrose (9.0 g, 26.3 mmol) in DMSO (41.0 g). The initial sucrose concentration by weight is 18.0 wt %. The catalyst/sucrose molar ratio is 0.100. The reaction medium is stirred at 70° C. for 4 hours. The yields at different reaction times are reported in table 3.

TABLE-US-00003 TABLE 3 Time 30 min 60 min 120 min 240 min Conv.sub.FRU 17.6 32.4 43.3 59.5 Yield.sub.GLU 100 100 100 100 Yield.sub.HMF 8.3 13.7 23.3 34.5

Example 4 (in Accordance) Conversion of Sucrose into 5-HMF and Glucose in the Presence of Hydrochloric Acid at 50° C.

[0097] Hydrochloric acid (1.0M in Et.sub.2O) (2.63 mmol) is added to a solution of sucrose (9.0 g, 26.3 mmol) in DMSO (41.0 g). The initial sucrose concentration by weight is 18.0 wt %. The catalyst/sucrose molar ratio is 0.100. The reaction medium is stirred at 50° C. for 4 hours. The yields at different reaction times are reported in table 4.

TABLE-US-00004 TABLE 4 Time 30 min 60 min 120 min 240 min Conv.sub.FRU 66.9 73.5 83.7 90.8 Yield.sub.GLU 100 100 92.3 94.8 Yield.sub.HMF 25.6 37.0 48.4 58.6

Example 5 (in Accordance) Conversion of Sucrose into 5-HMF and Glucose in the Presence of Hydrochloric Acid at 90° C.

[0098] Hydrochloric acid (1.0M in Et.sub.2O) (2.63 mmol) is added to a solution of sucrose (9.0 g, 26.3 mmol) in DMSO (41.0 g). The initial sucrose concentration by weight is 18.0 wt %. The catalyst/sucrose molar ratio is 0.100. The reaction medium is stirred at 90° C. for 4 hours. The yields at different reaction times are reported in table 5.

TABLE-US-00005 TABLE 5 Time 30 min Conv.sub.FRU 100 Yield.sub.GLU 84.8 Yield.sub.HMF 74.5

Example 6 (not in Accordance) Conversion of Sucrose into 5-HMF and Glucose in the Presence of Hydrochloric Acid at 120° C.

[0099] Hydrochloric acid (1.0M in Et.sub.2O) (2.63 mmol) is added to a solution of sucrose (9.0 g, 26.3 mmol) in DMSO (41.0 g). The initial sucrose concentration by weight is 18.0 wt %. The catalyst/sucrose molar ratio is 0.100. The reaction medium is stirred at 120° C. for 4 hours. The yields at different reaction times are reported in table 6.

TABLE-US-00006 TABLE 6 Time 30 min 60 min 120 min 240 min Conv.sub.FRU 100 100 100 100 Yield.sub.GLU 47.5 39.0 35.9 32.1 Yield.sub.HMF 77.2 77.9 79.0 80.8

Example 7 (not in Accordance) Conversion of Glucose Alone into 5-HMF in the Presence of Hydrochloric Acid at 70° C.

[0100] Hydrochloric acid (1.0M in Et.sub.2O) (2.50 mmol) is added to a solution of glucose (4.5 g, 25.0 mmol) in DMSO (45.5 g). The initial glucose concentration by weight is 9.0 wt %. The catalyst/glucose molar ratio is 0.100. The reaction medium is stirred at 70° C. for 4 hours. The yields at different reaction times are reported in table 7.

TABLE-US-00007 TABLE 7 Time 30 min 60 min 120 min 240 min Conv.sub.FRU — — — — Yield.sub.GLU 90.2 83.3 72.9 59.6 Yield.sub.HMF 0 0 0 0

Example 8 (not in Accordance) Conversion of Fructose Alone into 5-HMF in the Presence of Hydrochloric Acid at 70° C.

[0101] Hydrochloric acid (1.0M in Et.sub.2O) (0.55 mmol) is added to a solution of fructose (2.0 g, 11.1 mmol) in DMSO (20.0 g). The initial fructose concentration by weight is 9.1 wt %. The catalyst/fructose molar ratio is 0.050. The reaction medium is stirred at 70° C. for 4 hours. The yields at different reaction times are reported in table 8.

TABLE-US-00008 TABLE 8 Time 30 min 60 min 120 min 240 min Conv.sub.FRU 73.2 87.4 96.0 99.2 Yield.sub.GLU — — — — Yield.sub.HMF 49.0 61.2 71.9 76.7

[0102] In examples 1 to 4 (in accordance) carried out at temperatures of less than or equal to 80° C., the conversion carried out at low temperature makes it possible to obtain good yields of glucose (YieldGLu>80%), which is not converted into undesired products, while making it possible to obtain a conversion of fructose into 5-HMF with yields ranging up to 77% under the most effective conditions (examples 1 and 2).

[0103] Surprisingly, glucose is converted less rapidly in the presence of fructoside units (examples 1 and 2) than in its absence under the same conditions (example 7). The presence of glucose or of glucoside units does not appreciably affect the yields obtained from fructoside units or fructose (examples 1 and 2 vs. example 8 with fructose alone); on the contrary, the presence of glucose or of glucoside units surprisingly improves the conversion of fructose after 30, 60 or 120 minutes, and also the 5-HMF yield.

[0104] In example 5 (in accordance) carried out at a temperature of 90° C., yields of 85% and 75% of glucose and 5-HMF respectively are obtained with short reaction times, but a longer reaction time results in a deterioration in the glucose yield without, however, appreciably improving the 5-HMF yield.

[0105] In example 6 (not in accordance) carried out at a temperature of greater than 90° C., in particular than 100° C., the glucose yield does not exceed 50% without the 5-HMF yield being appreciably greater than 75-80%.

[0106] In example 7 (not in accordance) carried out at a temperature of 70° C., for 240 minutes, only with glucose, the glucose yield is less than 60% without production of 5-HMF.

[0107] In example 8 (not in accordance) carried out at a temperature of 70° C. only with fructose, the fructose yield does not exceed 50% after reaction for 30 minutes with a moderate fructose conversion of 70%.