DE102008009933A1 - Preparing 5-hydroxymethylfurfural, useful e.g. to manufacture pharmaceutical products such as fungicides, comprises thermally reacting carbohydrates in ionic liquid and discharging formed 5-hydroxymethylfurfural using extracting agent - Google Patents

Abstract

Preparing 5-hydroxymethylfurfural (HMF) comprises thermally reacting carbohydrates, preferably monosaccharides, in an ionic liquid and discharging the formed HMF by an extracting agent, where: the extracting agent does not or slightly soluble in the ionic liquid, which is dibutyl ether, the ionic liquid phase containing the carbohydrates is contacted with steam in a room temperature heated zone to form an ionic liquid phase separated extraction phase with a density lower than the ionic liquid phase for the continuous discharge of the extracting agent by reactive extraction of dissolved HMF. ACTIVITY : Fungicide. MECHANISM OF ACTION : None given.

Description

The The invention relates to a novel reactive extractive process for the continuous production of 5-hydroxymethylfurfural Carbohydrates, in particular monosaccharides, with the aid of ionic Liquids.

5-hydroxymethyl furfural (also called HMF in the following) is an intramolecular dehydration product of hexoses of general formula I.

renewable Raw materials such as starch, cellulose, sucrose or inulin, are inexpensive starting materials for the production of hexoses, like glucose and fructose.

HMF has antibacterial and corrosion inhibiting properties. From a chemical point of view, it shows multifunctional character with a rich following chemistry. For example, it is possible without great difficulty to produce furfuryldialcohol, -dialdehyde and -dicarboxylic acid and derivatives thereof; Likewise, the hydrogenation of the ring leads to difunctional 2,5-tetrahydrofuran derivatives. Different difunctional furan derivatives substituted at C-2 and C-5 are also readily accessible from HMF. It is therefore expected that HMF and 2,5-furandicarboxylic acid will become increasingly important as platform chemicals for the production of polymers based on renewable raw materials, pharmaceutical products such as fungicides, ligands in catalysis, in imaging processes, in electro-optical devices, etc. The use in cancer therapy is also currently being discussed (eg K. Michail, V. Matzi, A. Maier, R. Herwig, J. Greilberger, H. Juan, O. Kunert, R. Wintersteiger: Hydroxymethylfurfural: an enemy or a friendly xenobiotic? A bioanalytical approach, Analytical and Bioanalytical Chemistry, 387, 2007, 2801-2814 ). At the moment, however, the industrial use of the HMF is prevented by the very high production costs that result from complex and complex product separation processes. HMF is, in principle, an intermediate in the dehydrating decomposition of hexoses to levulinic acid and formic acid, that is, it is crucial to the time at which the reaction is terminated. Thus, the separation of HMF from the starting saccharides and by-products becomes an important step in its production. In addition to glucose and fructose, fructose-containing carbohydrates, sucrose, fructose syrups, eg. B. high fructose corn syrup (HFCS, iso-glucose), mother liquors of fructose crystallization or polymeric fructosides, such as inulin, in question. Even the inulin-containing chicory (inulin content about 18%) is suitable directly or as mus mixed with water for the preparation of a fructose-containing solution. Since glucose, even in polymeric form as starch or cellulose is synthesized by photosynthesis in almost unlimited amount by nature and glucose can be converted by an isomerization to fructose, come as starting materials for the synthesis of HMF and invert, hydrolyzed wood, waste from the Paper and wood industry and corn starch, which are easily accessible in large quantities.

Especially suitable starting material for the production of HMF Mother liquors of fructose crystallization.

The conversion of monosaccharides, such as, for example, fructose, to HMF is generally understood as an intramolecular condensation reaction in which three moles of water are released per mole of monosaccharide unit. Like other condensations, this acid catalyzes. It is known that when using very strong acids or at high reaction temperatures, various by-products are formed. In addition to levulinic acid and formic acid, especially brown-black compounds occur in sometimes non-negligible amounts, which are referred to as humins ( EP 0230250 A2 ). Not least because a further purification step is necessary, these significantly reduce the efficiency of a process.

Interestingly, the formation of by-products is dependent on the starting concentration of the monosaccharide solution: the higher this is, the higher the formation rates for the by-products ( BFM Kuster, HS Van der Baan: The influence of the initial and catalyst concentrations on the dehydration of D-fructose, Carbohydrate Research, 54, 1977, 165-176 ; Y. Román-Leshkov, JN Chheda, JA Dumesic: Phase modifiers promote efficient production of hydroxymethylfurfural from fructose, Science, 312, 2006, 1933-1937 ; US 3,071,599 ).

Out From a chemical point of view, the production of HMF should be as possible dilute solutions happen, with the with large solvent volumes increasing procedural Effort must be kept within limits.

• a) Synthese
• b) Produkttrennung
• c) Produktreinigung.

The production of HMF basically has to be subdivided into three process steps:

• a) Synthesis
• b) Product separation
• c) product cleaning.

The Synthesis of HMF is basically not a big one Problem and has already been extensively in the scientific and intellectual property literature. Some of these approaches (Acid catalysis and catalyst-free reactions) listed below by way of example.

The condensation of monosaccharides to HMF is catalyzed by acids, for example with HCl at 100 ° C-200 ° C and atmospheric pressure, in water ( BFM Kuster, HS Van der Baan: The Influence of the Initial and Catalyst Concerns of the Dehydration of D-fructose, Carbohydrate Rearch, 54, 1977, 165-176 ; BFM Kuster: The Influence of Water Concentration on the Dehydration of D-fructose, Carbohydrate Rearch, 54, 1977, 177-183 ; JP 2005232116 ; JP 2005200321 ), in polyethylene glycol ( BFM Kuster, J. Laurens: Preparation of 5-hydroxymethylfurfural Part II. Dehydration of fructose in a tube reactor using polyethylene glycol as solvent, Starch / Stärke, 29, 1977, 172-176 ; BFM Kuster: The Influence of Water Concentration on the Dehydration of D-fructose, Carbohydrate Research, 54, 1977, 177-183 ) or in two-phase systems (aqueous DMSO / methyl isobutyl ketone + 2-butanol). Sulfuric acid was treated at 180 ° C and 20 MPa in subcritical or supercritical acetone / water mixtures ( M. Bicker, J. Hirth, H. Vogel: Dehydration of fructose to 5-hydroxymethylfurfural in sub and supercritical acetone, Green Chemistry, 5, 2004 280-284 ) as well as in subcritical or supercritical water ( M. Watanabe, Y. Aizawa, T. Lida, TM Aida, C. Levy, K. Sue, H. Inomata: Glucose Reactions with Acid and Base Catalyst in Hot Compressed Water at 473 K, Carbohydrate Research, 340, 2005, 1925 -1930 ; US 2,851,468 ) or water ( EP 0230250 ; US 4,400,468 ) used.

Also oxalic acid ( WN Haworth, W. Jones: The conversion of sucrose into furan compounds. Part I. 5-Hydroxymethylfurfuraldehydes and some derivatives, Journal of the Chemical Society, 1944, 667-670 ) and levulinic acid ( US 2,929,823 ) may be mentioned here as catalysts.

It is also known that Lewis acids, such as boron trifluoride etherate ( HH Szmant, DD Chundury: The preparation of 5-hydroxymethylfurfuraldehydes from high fructose corn syrup and other carbohydrates, Journal of Chemical Technology and Biotechnology, 31, 1981, 135-145 ) and aluminum compounds ( US 3,483,228 ; US 3,071,599 ).

The use of transition metal catalysts ( SU 1054349 ; SU 1351932 ; C. Carlini, P. Patrono, AM Raspolli Galletti, G. Sbrana: Heterogeneous Catalysts Based on Vanadyl Phosphate for Saccharide Dehydration to 5-Hydroxymethyl-2-furaldehyde, Applied Catalysis A: General, 275, 2004, 111-118 ; H: Zhao, JE Holladay, H. Brown, ZC Zhang ; Metal chlorides in ionic liquid converters sugars to 5-hydroxymethylfurfural, Science, 316, 2007, 1597-1600 ) as well as lanthanides ( JP 10265468 ; K.-I. Seri, Y. Inoue, H. Ishida: Highly efficient catalytic activity of lanthanide (III) ions for conversion of saccharides to 5-hydroxymethyl-2-furfural in organic solvents, Chemistry Letters, 29, 2000, 22-23 ), which, however, probably have no industrial relevance simply because of their costs.

Since long contact times with the acid often lead to side reactions (formation of levulinic acid and humic substances) and associated low HMF yields, so-called azido-basic systems have been developed in which the acidity is buffered by the presence of a base. Examples of such systems have been described ( C. Fayet, J. Gelas: Nouvelle méthode de préparation du 5-hydroxyméthyl-2-furaldéhyde par action de sels d 'ammonium ou d' immonium sur les mono-, oligo- poly-saccarides. Accès direct aux 5-halogénométhyl-2-furaldéhydes, Carbohydrate Research, 122, 1983, 59-68 ; C. Moreau, A. Finiels, L. Vanoye: Dehydration of fructose and sucrose into 5-hydroxymethylfurfural in the presence of 1-H-3-methylimidazolium chloride, both as solvent and catalyst, Journal of Molecular Catalysis A: Chemical, 253 , 2006, 165-169 ). Here, the reaction of HCl or p-toluenesulfonic acid is catalyzed, which are buffered by the addition of pyridine or other amines. Without the addition of a solvent, up to 70% HMF could be obtained from fructose without producing levulinic acid or humic substances as by-products. The combination of these buffered systems with solvent mixtures is also known ( ML Mednick: The acid-base catalyzed conversion of aldohexose into 5- (hydroxymethyl) -2-furfural, Journal of Organic Chemistry, 27, 1962, 398-403 ; US 3,118,912 ). However, no technical method of subsequent product tren tion or recycling of the catalyst.

Another possibility of acid catalysis is the synthesis of the HMF with microporous or macroporous heterogeneous catalysts, such as, for example, zeolites or ion exchangers in various solvents (water, DMSO, supercritical carbon dioxide, methyl isobutyl ketone) ( L. Rigal, A. Gaset, J.-Gorrichon: Selective conversion of D-fructose to 5-hydroxymethyl-2-furancarboxaldehydes using a water-solvent ion exchange resin triphasic system, Industrial and Engineering Chemistry Product Research and Development, 20, 1981, 719-721 ; GA Halliday, RJ Young, VV Grushin: Onepot, two-step, practical catalytic synthesis of 2,5-diformylfuran from fructose, Organic Letters, 5, 2003, 2003-2005 ; Y. Román-Leshkov, JN Chheda, JA Dumesic: Phase modifiers promote efficient production of hydroxymethylfurfural from fructose, Science, 312, 2006, 1933-1937 ; C. Moreau, R. Durand, J. Duhamet, P. Rivalier: Hydrolysis of fructose and glucose precursors in the presence of H-form zeolites, Carbohydrate Chemistry, 16, 1997, 709-714 ; C. Moreau, R. Durand, S. Razigade, J. Duhamet, P. Faugeras, P. Rivalier, P. Ros, G. Avignon: Dehydration of fructose to 5-hydroxymethylfurfural over H-mordenites, Applied Catalysis A: General, 145, 1996, 211-224 ; C. Moreau, R. Durand, C. Pourcheron, S. Razigade: Preparation of 5-hydroxymethylfurfural from fructose and precursors over H-form zeolites, Industrial Crops and Products, 3, 1994, 85-90 ; FR 2670209 ; JP 03099072 ; FR 2664273 ; DE 196 19 075 A1 ; DE 30 33 527 C2 ; WO 03024947 ; WO 9617837 . US 4,590,283 ; US 4,339,387 ). These systems give high yields when operating at high temperatures. In the case of supercritical carbon dioxide, the process design of the process is technically difficult and energetically less efficient. It should also be noted that the heterogeneous catalysts used have only a short service life, since they are not sufficiently thermostable.

Among the catalyst-free reactions is the synthesis with DMSO or DMF for the condensation of fructose to HMF, with yields of up to 90% HMF at 150 ° C in two hours, and the formation of condensation byproducts were suppressed ( RM Musau: The preparation of 5-hydroxymethyl-2-furaldehyde (HMF) from D-fructose in the presence of DMSO, Biomass, 13, 1987, 67-74 ; BMF Kuster: 5-hydroxymethylfurfural (HMF). A review focussing on its manufacture, Starch / Strength, 42, 1990, 314-321 ; MJJ Antal, WSL Mok, GN Richards: Mechanism of formation of 5- (hydroxymethyl) -2-furaldehydes from D-fructose and sucrose, Carbohydrate Research, 199, 1990, 91-109 ; HE van Dam, APG Kieboom, H. van Bekkum: The conversion of fructose and glucose into acidic media: Formation of hydroxymethylfurfural, Starch / Stärke, 38, 1986, 95-101 ; TG Bonner, EJ Bourne, M. Ruszkiewicz: The iodine-catalysed conversion of sucrose into 5-hydroxymethylfurfuraldehyde, Journal of the Chemical Society, 1960, 787-791 ; FR 266963 ; FR 2669635 ; WO 03024947 ). Disadvantages of this synthesis route are its poor reproducibility ( GA Halliday, RJ Young, VV Grushin: One-pot, two-step, practica catalytic synthesis of 2,5-diformylfuran from fructose, Organic Letters, 5, 2003, 2003-2005 ) and the technically inefficient product separation of high-boiling solvents, such as DMSO or DMF.

Different as the synthesis of HMF is the product separation and purification most elaborate, resulting in the few in the literature reflects the methods described. Depending on the reaction The synthesis step offers different product separation methods generally, for most of the overall process costs are responsible.

If, as described above, dissolved or liquid acids are used as catalysts which give a liquid phase with the monosaccharide solution, in many cases it is neutralized by addition of a base (eg. EP 0230250 ). This results in at least equivalent amounts of salts, which require a further filtration step and then have to be disposed of. Today, this is neither efficient from an ecological nor economic point of view.

A Product separation by vacuum distillation is not in the case of HMF given because the product tends to thermal decomposition.

alternative must be extracted during or after the reaction. These methods are based on the use of a two-phase system (liquid-liquid), in which the first phase the Saccharide solution and the catalyst contains (reaction phase), and with the second phase the product HMF is extracted (extraction phase).

Examples are water methyl isobutyl ketone ( L. Rigal, A. Gaset, A., J.-P. Gorrichon: Selective conversion of D-fructose to 5-hydroxymethyl-2-furancarboxaldehydes using a water-solvent-ion exchange resin triphasic system, Industrial and Engineering Chemistry Product Research and Development, 20, 1981, 719-721 ; C. Moreau, R. Durand, S. Razigade, J. Duhamet, P. Faugeras, P. Rivalier, P. Ros, G. Avignon: Dehydration of fructose to 5-hydroxymethylfurfural over H-mordenites, Applied Catalysis A: General, 145, 1996, 211-224 ; C. Moreau, R. Durand, C. Pourcheron, S. Razigade: Preparation of 5-hydroxymethylfurfural from fructose and precursors over H-form zeolites, Industrial Crops and Products, 3, 1994, 85-90 ; FR 2670209 ; GB 876463 ; US 2,917,520 ; WO 9617837 . US 4,590,283 ; US 4,339,387 ), Water-butanol ( US 2,750,394 ), Pyridine hydrochloride-ethyl acetate ( C. Fayet, J. Gelas: Nouvelle méthode de preparation du 5-hydroxymethyl-2-furaldéhyde par action de sels d 'ammonium ou d' immonium sur les mono-, oligo- et polysaccarides. Accès direct aux 5-halogénométhyl-2-furaldéhydes, Carbohydrate Research, 122, 1983, 59-68 ), Water furfural ( US 2,929,823 ), and water with aromatic or halogenated organic solvents ( US 6,441,202 ; US 20020123636 ; US 20030032819 ).

As GB 876463 evidenced, after extraction a complex work-up concept in the further course of the purification necessary (concentration, column chromatography, post-extraction), since on the one hand formed by-products (eg levulinic acid and humic substances) must be separated from the HMF. On the other hand, a high selectivity of the extractant for the HMF is difficult to achieve because the monosaccharides used, the acid used as a catalyst and the by-products have a similar high polarity as the product HMF and an extractive separation by entrainment of the reaction phase is insufficient (for example DW Brown, AJ Floyd, RG Kinsman, Y. Roshanhyphen: Dehydration reactions of fructose in nonaqueous media, Journal of Chemical Technology and Biotechnology, 32, 1982, 920-924 ).

The problem of product separation is well illustrated by the complexity of a process that was first introduced in 2006: To ensure high yields of HMF, the reaction of the fructose with HCl is catalyzed. The reaction phase, consisting of DMSO and water, must be modified with poly (1-vinyl-2-pyrrolidone), which increases the selectivity of the reaction. The optimal extraction phase again consists of a solvent mixture (methyl isobutyl ketone and 2-butanol). Both high-boiling solvents must be removed from the product by distillation after extraction, which requires a high process outlay, in particular a high energy requirement ( Y. Román-Leshkov, JN Chheda, JA Dumesic: Phase modifiers promote efficient production of hydroxymethylfurfural from fructose "Science, 312, 2006, 1933-1937 ; JN Chheda, Y. Román-Leshkov, JA Dumesic: Production of 5-hydroxymethylfurfural and furfural by dehydration of biomass-derived mono-and polysaccharides, Green Chemistry, 9, 2007, 342-350 ).

Therefore, the use of microporous or macroporous heterogeneous catalysts, for example by filtration or by using a fixed bed reactor in countercurrent ( P. Rivalier, J. Duhamet, C. Moreau, R. Durand: Development of a Continuous Catalytic Heterogeneous Column Reactor with Simultaneous Extraction of an Intermediate Product by an Organic Solvent circulating in a countercurrent manner with the aqueous phase, Catalysis Today, 24, 1995 , 165-171 ) can be removed from the product-containing solvent, only a few advantages.

In order to achieve the purities required for the platform chemical HMF, the product separation must be followed by a further product purification, which further increases the process complexity, with which the above-mentioned reaction- and process-inherent impurities are removed. The literature gives little information about the methods used for this and the purities achieved. EP 0230250 and US 4,740,605 describe the use of a time and energy consuming chromatographic workup (three column system, ion exchange column to remove colored and acidic by-products), followed by crystallization of the product from water.

The Most of the above methods are operated intermittently.

A continuous process management is described only in a few cases, which are based exclusively on two-phase (liquid-liquid) solvent systems, such as water-methyl isobutyl ketone. When solid catalysts are used in a fixed bed, the extraction with methyl isobutyl ketone and other non-water-soluble solvents can be carried out in countercurrent ( P. Rivalier, J. Duhamet, C. Moreau, R. Durand: Development of a Continuous Catalytic Heterogeneous Column Reactor with Simultaneous Extraction of an Intermediate Product by an Organic Solvent circulating in a countercurrent manner with the aqueous phase, Catalysis Today, 24, 1995 , 165-171 ; BFM Kuster, HJC van der Stehen: Preparation of 5-hydroxymethylfurfural Part I. Dehydration of fructose in a continuous stirred tank reactor, Starch / Stärke, 29, 1977, 99-103 ; US 4,339,387 ; US 2,917,520 ; WO 2005018799 ). According to Kuster et al. Herein, however, the decomposition of HMF occurs faster than its extraction, so that the effectiveness of this system is very low ( BFM Kuster, HJC van der Stehen: Preparation of 5-hydroxymethylfurfural Part I. Dehydration of fructose in a continuous stirred tank reactor, Starch / Stärke, 29, 1977, 99-103 ). By using complex solvents Compositions (DMSO / water-methyl isobutyl ketone / 2-butanol) and addition of phase modifiers [poly (1-vinyl-2-pyrrolidone)] Although the extraction efficiency can be improved, but here the reaction phase must be nachextrahiert. In addition, the high-boiling solvents further complicate the work-up and, viewed over the entire process, lead to a poor process energy balance (US Pat. Y. Román-Leshkov, JN Chheda, JA Dumesic: Phase modifiers promote efficient production of hydroxymethylfurfural from fructose, Science, 312, 2006, 1933-1937 ).

The use of supercritical acetone-water mixtures with sulfuric acid catalyst is energetically complex (20 MPa, 180 ° C, subsequent chromatographic purification) and therefore unacceptable for commercial applications, although quantitative conversions were achieved at 77% selectivity ( M. Bicker, J. Hirth, H. Vogel: Dehydration of fructose to 5-hydroxymethylfurfural in sub and supercritical acetone, Green Chemistry, 5, 2004 280-284 ; M. Bicker, D. Kaiser, L. Ott, H. Vogel: Dehydration of D-fructose to hydroxymethylfurfural in sub and supercritical fluids, Journal of Supercritical Fluids, 36, 2005, 118-126 ; EP 0230250 ; DE 36 01 281 C2 ).

In summary It should be noted that the production of HMF is relatively large technological problems and that still no economic advantageous manufacturing method is available.

The Tendency of HMF, especially at high initial concentrations of Monosaccharides and / or when using strongly acidic catalysts To form by-products, requires the continuous reaction, removed from the HMF immediately after the formation of the reaction phase becomes. Although this is by using an extractant means two-phase (liquid-liquid) process control implemented. In practice, however, it has been shown that due to the very similar polarities of monosaccharides, HMF and the catalyst always a contamination of the extraction phase results, so that subsequently, further, procedural and efficiency-reducing purification steps must follow. These and the solvent recycling require in particular a great temporal, apparative and energetic Effort.

Of the Invention is based on the object, also for large-scale Processes to create profitable process with the 5-hydroxymethylfurfural as low as possible from carbohydrates, in particular monosaccharides, of different origin, composition, and purity in high Yields can be produced.

These Task is in a process for the preparation of 5-hydroxymethylfurfural by thermal conversion of carbohydrates, in particular monosaccharides, in an ionic liquid and discharge in this formed 5-Hydroxymethylfurfurals using an extractant solved according to the invention that as extractant one in the ionic liquid no or only negligibly soluble liquid, such as dibutyl ether, is provided which the ionic Liquid phase containing the carbohydrates and if necessary, additives in a temperature-controlled reaction zone, for example in a heated to above room temperature reactor, flowing contacted.

With this flowing contact (flow or contacting by-pass) becomes one of the ionic Liquid phase separate extraction phase with lower Density created in which the ionic liquid phase 5-hydroxymethylfurfural produced by "reactive extraction" is, d. H. that generated in the ionic liquid phase 5-hydroxymethylfurfural goes directly with its formation continuously immediately into the extraction phase.

Surprised has shown that with such a "reactive extraction" arising HMF not only continuous, but also complete and selectively, d. H. without due to other constituents of the ionic liquid phase (ionic liquid, carbohydrates and / or additives) to be contaminated, transferred to the extraction phase and thus can be removed from the reactor without this resort to complex solvent compositions to have and (as in the prior art described above most disadvantageous) in this regard immense expenses for separating the HMF from the constituents of the reaction phase to operate. A separation of the selective in the Extraction phase transferred HMF from not in the ionic liquid soluble extractant (Such are exemplified in the subclaims) is with known thermal separation methods, such. B. distillation or permeation which is not the subject of the present invention should be, also for large-scale and continuous Processes (against the problematic removal other, already known and listed in the prior art Reaction phases) relatively aufwandgering possible.

In this way, a method is provided with the invention, in contrast to known Methods technically and economically advantageous and also on a large scale HMF high purity continuously, in high yields and with the help of ionic liquids from carbohydrates of different origin can be obtained. The use of complex solvent compositions for the separation of the HMF from the ionic liquid phase, which in the known processes must subsequently be separated from the dissolved HMF only with difficulty and with the greatest effort, is not necessary in the process according to the invention.

By the selective conversion of the HMF from the ionic Liquid phase remain their constituents in the Reaction zone and do not necessarily constantly be fed again, which continues the process cost reduced.

It has also been shown that even oligo- and polysaccharides as Carbohydrates without required prior digestion by acid Hydrolysis for HMF recovery can be found by using these long-chain compounds directly in the ionic liquid phase, if necessary, with the addition of suitable additives, are broken. Also Under these conditions HMF is generated, which according to the invention immediately after its formation very selectively transferred to the extraction phase becomes.

• – Flüssigkeiten, die im Gegensatz zu molekularen Lösungsmitteln zumindest formal vollständig aus Anionen und Kationen bestehen ( Wilkes, J. S.: A short history of ionic liquids – from molten salts to neoteric solvents, Green Chemistry, 4, 2002, 73–80 ). Dementsprechend ist geschmolzenes Natriumchlorid im Prinzip eine ionische Flüssigkeit mit einem hohen Schmelzpunkt (808°C). Vorteilhaft ist der Einsatz von niedrigschmelzenden ionischen Flüssigkeiten, wobei „niedrigschmelzend" im Zusammenhang mit ionischen Flüssigkeiten bedeutet, dass die reine ionische Flüssigkeit bei einem Druck von 1 bar (101,325 kPa) einen Schmelzpunkt von maximal 150°C besitzt.
• – Flüssigkeiten mit großem Temperaturbereich (bis zu 400°C) ( Ngo, H. L., LeCompte, L., Hargens, L., McEwen, A. B.: Thermal properties of imidazolium ionic liquids, Thermochimica Acta, 357, 2000, 97–102 ).
• – Flüssigkeiten, die praktisch keinen Dampfdruck besitzen ( Wilkes, J. S.: A short history of ionic liquids – from molten salts to neoteric solvents, Green Chemistry, 4, 2002, 73–80 ).

Ionic liquids (molten salts) for carrying out the method are

• - Liquids which, unlike molecular solvents, at least formally consist entirely of anions and cations ( Wilkes, JS: A short history of ionic liquids - from molten salts to neoteric solvents, Green Chemistry, 4, 2002, 73-80 ). Accordingly, molten sodium chloride is in principle an ionic liquid with a high melting point (808 ° C). The use of low-melting ionic liquids is advantageous, with "low-melting" in connection with ionic liquids meaning that the pure ionic liquid has a melting point of at most 150 ° C. at a pressure of 1 bar (101.325 kPa).
• - Liquids with a wide temperature range (up to 400 ° C) ( Ngo, HL, LeCompte, L., Hargens, L., McEwen, AB: Thermal properties of imidazolium ionic liquids, Thermochimica Acta, 357, 2000, 97-102 ).
• - liquids that have virtually no vapor pressure ( Wilkes, JS: A short history of ionic liquids - from molten salts to neoteric solvents, Green Chemistry, 4, 2002, 73-80 ).

The physical and chemical properties of ionic liquids are significantly influenced by their composition, d. H. through the choice of anion and to some extent through the size of the cation. So can both hydrophobic as well as hydrophilic ionic liquids become.

Ionic liquids can be described by the general formula II: A ⁺ B ^- , (II) where A ^{+ is} an organic cation and B ^{- is} an anion. This anion can be both organic and inorganic.

The term "organic cation" formally describes an organic molecule in which a non-metal atom has lost one or more electrons to another atom or atoms so that the organic molecule carries a positive charge and thus is a cation concentrated on one atom or distributed over several atoms, for example the 1-butyl-3-methylimidazolium cation (formula III):

For the present invention includes interesting cations except Carbon and hydrogen atoms at least one heteroatom, with which essentially combines the cationic functionality is, for. For example, tetraalkylammonium or phosphonium.

Especially of interest are those organic cations consisting of a heterocyclic, in particular a heteroaromatic system in which the Charge over the entire heteroaromatic system or parts of which is distributed (delocalised). examples for this are the 1-alkyl-3-methylimidazolium or N-alkylpyridinium.

Of the Expression "Heteroatom" stands for an atom from the 5th or 6th main group of the Periodic Table of the Elements, in particular for nitrogen, phosphorus, oxygen and sulfur. "Heteroaromatic Systems "are ring systems that follow the well-known rules of Obey Aromaticity, so are pseudoaromatic. "Heterocyclic Systems "are ring systems, where no aromaticity is present.

In particular, the cation has the general formula [RX] ⁺ , where X is the heteroatom-containing part of the cation, and R is a hydrogen, C _1-10 -alkyl, C _2-10 -alkenyl or C _5-10 -aryl, the or one of the heteroatom (s) is bound. The terms "C _1-10 -alkyl", "C _2-10 -alkenyl", "C _5-10 -aryl" are used below as follows:
"C _1-10 -alkyl" represents a fully saturated linear, cyclic or branched carbon chain having 1 to 10 carbon atoms, such as, for example, methyl, ethyl, propyl, isopropyl, cyclopropyl, n-butyl, tert-butyl, isobutyl, Cyclobutyl, n-pentyl, cyclopentyl, hexyl, cyclohexyl, decyl.

Similarly, "C _2-10 alkenyl" means an unsaturated, ie, containing at least one double bond, linear, cyclic or branched carbon chain having 2 to 10 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, allyl, 1 Butenyl, 1-hexenyl, 3-cyclohexenyl.

Similarly, "C _5-10 aryl" means an aromatic carbon skeleton of 5 to 10 carbon atoms.

Such aryl, alkyl and alkenyl carbon chains may further contain one or more of the following groups: fluorine, chlorine, bromine, iodine, oxygen, sulfur, phosphorus and / or nitrogen atoms, such as in -OH, -SH, -NH ₂ , ester, aldehyde, ketone, ether, thiol, thioether, nitrile, carboxylic acid, phosphine, nitro, phenyl, and sulfonate groups, etc.

Examples Compounds X are the following hetero compounds and theirs homologs obtained by substitution: 1-alkylimidazole, 1,2-dialkylimidazole, 1-alkenylimidazole, 1-alkoxyimidazole, imidazole, 1-arylimidazole, 2-alkylimidazole, Ammonia, quinoline, isoquinoline, pyridine, alkylpyridine, pyrrolidine, N-alkylpyrrolidine, N-alkenylpyrrolidine, N-alkoxypyrrolidine, morpholine, N-alkylmorpholine, N-alkenylmorpholine, N-alkoxymorpholine, acridine, Azepine, benzimidazole, benzoquinoline, benzothiazole, benzothiazoline, Benzothiophene, benzotriazole, benzoxazole, benzthiazole, carbazole, Quinazole, quinazoline, quinoxaline, quinuclidine, caffeine, dithiane, Furazan, imidazolidine, imidazoline, indazole, indole, indoline, indolizine, Isoindoline, isothiazole, isoxazole, melamine, naphthyridine, oxadiazole, Oxazole, phenantridine, phenanthroline, phenazine, phenothiazine, phenoxadine, Phthalazine, piperazine, piperidine, pteridine, purine, pyrazine, pyrazolidine, Pyrazoline, pyridazine, pyrimidine, pyrrole, pyrroline, pyryl, tetrazole, Thiadiazine, thiazine, thiomorpholine, thionaphthene, thiophene, triazine, Trithian, Trophan, etc.

Further examples of such compounds X represent the formulas IV and V: PY ¹ Y ² Y ³ (IV) NY ¹ Y ² Y ³ , (V) wherein Y ¹ , Y ² and Y ^{3 are} hydrogen, "C _1-10 alkyl", "C _2-10 alkenyl", "C _5-10 aryl" and may be the same or different from each other.

Of the The term "substitution" refers to the formal Replacing usually hydrogen atoms on the carbon atoms the heteroatom carbon skeletons listed above. These hydrogen atoms can be replaced by non-metals of the 4th, 5th, 6th or 7th main group of the periodic table of elements replaced become.

Cations of the type 1- (C _1-10 -alkyl) -3- (C _1-10 -alkyl) imidazolium and N- (C _1-10 -alkyl) pyridinium have proven to be of particular industrial relevance.

The anion can be an organic or inorganic anion. There is a large number of selectable anions available, such as F ^-, Cl ^-, Br ^-, I ^-, OH ^-, NO ₃ ^-, BF ₄ ^-, PF ₆ ^-, FeCl ₄ ^-, ZnCl ₃ ^-, SnCl ₅ ^- , AsF ₆ ^- , SbF ₆ ^- , AlCl ₄ ^- , CF ₃ CO ₂ ^- , NiCl ₃ ^- , ClO ₄ ^- , [(CF ₃ SO ₂ ) ₂ N] ^- , CF ₃ SO ₃ ^- , CN ^- , ( CN) ₂ N ^- , (CF ₃ SO ₂ ) ₃ C ^- , (CF ₃ ) ₂ PF ₄ ^- , (CF ₃ ) ₃ PF ₃ ^- , (CF ₃ ) ₅ PF ^- , (CF ₃ ) ₆ P ^- , SF ₅ CF ₂ SO ₃ ^- , SF ₅ CHFCF ₂ SO ₃ ^- , CF ₃ CF ₂ (CF ₃ ) ₂ CO ^- , (CF ₃ SO ₂ ) ₂ CH ^- , (SF ₅ ) ₃ C ^- , [O (CF ₃ ) ₂ C ₂ CF ₃ ) ₂ O] ₂ PO ^- , [H (CF ₃ SO ₃ ) ₂ ] C ^- , (CF ₃ ) ₂ N ^- , B (CN) ₄ ^- , (C ₂ F ₅ ) ₂ P (O) O ^-, (C ₂ F _{5) 3} PF ₃ ^-, (C ₃ F _{7) 3} PF ₃ ^-, (C ₄ F _{9) 3} PF ₃ ^-, CO (CO) ₄ ^-, HSO ₃ ^- , HSO ₄ ^- , H ₂ PO ₄ ^- , HPO ₄ ^2- , BCl ₄ ^- , SO ₄ ^2- , CO ₃ ^2- , "C _5-10 -aryl" sulfonate, "C _1-10 -alkyl" sulfonate, "C _1-10 alkyl" sulfate, di "C _1-10 alkyl" phosphate, "C _1-10 alkyl" phosphonate, C "phosphonate" _5-10 aryl C _2-10 -alke nyl "sulfonate," C _2-10 alkenyl "carbonate," C _2-10 alkenyl "phosphonate," C " _5-10 aryl" sulfate, "C _2-10 alkenyl" sulfate, bis (perfluoro "C _{1 -10-} alkyl "sulfonyl) amide, bis (perfluoro" C " _5-10 aryl" sulfonyl) amide, bis (perfluoro "C _2-10 alkenyl" sulfonyl) amide, "C _1-10 alkyl" carbonate, " C _5-10 -aryl "carbonate," C _1-10 -alkyl "carboxylate," C _2-10 -alkenyl "carboxylate or" C _5-10 -aryl "carboxylate, etc.

By clever combination of the above cations and anions Low melting point salts (less than 150 ° C at 1 bar), which corresponds to the definition "ionic liquids" obey, compiled.

The Invention is not limited to the exemplified ionic Limited liquids.

The ionic liquid is used to convert carbohydrates, in particular monosaccharides, to HMF and may be from an ionic Liquid as defined above, or from one Make a mixture of several such ionic liquids.

These Reaction phase, in which the conversion to HMF takes place, is called ionic Liquid phase referred to, which also contain additives can.

By "additive" is meant additives which, on the one hand, have a positive effect on the conversion of the carbohydrates to HMF, for example with regard to the selectivity or reaction rate of the reaction These additives have chemical structural elements which are also known as Lewis or Bronsted acids Additives are the Bronsted acids water, hydrochloric acid, sulfuric acid, phosphoric acid, HBF ₄ , HPF ₆ , CF ₃ SO ₃ H, [(CF ₃ SO ₂ ) ₂ ] NH, acetic acid, levulinic acid, and their anhydrides, such as acetic anhydride, trifluoromethanesulfonic anhydride and trifluoroacetic anhydride, and Lewis acids such as aluminum trichlorides and other metal halides.

To the others include chemical additives for definition of the additive, in the case of emulsion formation by support the coagulation of the ionic liquid phase and the Extraction phase support the phase separation or the Viscosity or the melting point of the ionic liquid phase decrease.

Itemized or mixture of several of these compounds can be used and are defined in their entirety as an "additive".

Carbohydrates, in particular monosaccharides, are to be defined here as compounds of the general empirical formula (CH ₂ O) _n , which include, for example, fructose and glucose. Furthermore, the term "carbohydrates" includes oligomers and polymers which formally arise from (CH ₂ O) _{n building} blocks by glycosidic linkage, for example starch (polyglucose), cellulose (polyglucose), sucrose or inulin (polyfructose) carbohydrates from renewable raw materials are also used for the commercial conversion to HMF, also directly occurring in nature resources, such as wood and chicory, as well as their chemically by digestion or physically (by grinding, pressing, extracting, etc.) pretreated secondary products as " Carbohydrates "or" monosaccharides ", such as fructose syrups, mother liquors of fructose or glucose crystallization, invert sugar, hydrolyzed wood, or wastes from the paper and wood industries, which are readily available in large quantities.

When particularly suitable starting material for the preparation HMF are mother liquors of fructose crystallization.

by virtue of the scope of the proposed method can also carbohydrates from different sources and compositions used as a mixture. Accordingly, the invention not limited to the exemplified carbohydrates.

The Carbohydrates become in the ionic liquid phase dissolved or dispersed with or without the aforementioned additives.

The concentration range of the carbohydrates is advantageously between 5 and 70 percent by weight, based on the ratio of the (CH ₂ O) ₆ units of the carbohydrates and the ionic liquid. The concentration range of the additive is expediently between 0 and 10 percent by weight, based on the ionic liquid phase. The ratio between carbohydrates, additive and ionic liquid depends, as known per se, in particular on the reaction temperature, the rate of formation of the by-products and the Solubility of carbohydrates in the ionic liquid phase from.

to Implementation of the method is a reactor with a Tempering proposed, with the help of the reactor advantageous reaction temperature is brought. expedient the conversion of carbohydrates to HMF takes place at temperatures between 50 ° C and 150 ° C, preferably between 70 ° C and 90 ° C operated. The chosen one Pressure is between 0.5 bar and 80 bar, preferably between 0.8 bar and 5 bar, at best at 1 bar.

Of the Reactor is advantageously constructed double-walled, so that the temperature conductively by means of steam or a heating fluid can. Alternatively, the temperature control by wrapping of the reaction vessel with heating bands or other heating happen. Another type of temperature control is given for example by the use of a high-frequency field, in which the reactor is located. Especially for the synthesis from HMF in a microwave oven, the process is very suitable because the reactor volume due to the advantages mentioned sufficiently small can be kept to the reactor advantageous in conventional Integrate microwave ovens. This will be a costly and technically difficult to realize magnification of the microwave oven irrelevant.

• – das HMF selektiv aus der ionischen Flüssigkeitsphase herauslöst, d. h. keine bzw. nur vernachlässigbar geringe Löslichkeit für die anderen Komponenten der ionischen Flüssigkeitsphase (ionische Flüssigkeit, Kohlenhydrate, Additive) besitzt.
• – die ionische Flüssigkeitsphase kontinuierlich durchströmt oder an dieser kontaktierend vorbeiströmt. Ein solcher Prozess ist dem Fachmann auch als Reaktivextraktion bekannt, die im Gegenstrom oder Gleichstrom stattfinden kann.
• – einen relativ geringen Siedepunkt hat, so dass sie anschließend möglichst aufwandgering vom HMF, beispielsweise durch Destillation, entfernt werden kann.
• – bei Reaktionstemperatur und Reaktionsdruck als Flüssigkeit vorliegt und
• – eine niedrigere Dichte als die ionischen Flüssigkeitsphase besitzt, so dass sie vorteilhaft aus dem Reaktorkopf entnommen werden kann.

According to the invention, the HMF, following its formation in the ionic liquid phase, passes continuously and selectively through the said reactive extraction into the extractant, which contacts the ionic liquid phase in a flowing manner. The extractant used is an organic solvent or a mixture of several organic solvents, which are defined in their entirety as the extraction phase. The extraction phase is characterized by the fact that they

• - The HMF selectively dissolves from the ionic liquid phase, ie no or only negligible solubility for the other components of the ionic liquid phase (ionic liquid, carbohydrates, additives) has.
• - Continuously flows through the ionic liquid phase or flows past contacting it. Such a process is also known to the person skilled in the art as reactive extraction, which can take place in countercurrent or direct current.
• - Has a relatively low boiling point, so that they can then as possible aufwandgering removed from the HMF, for example by distillation.
• - Is present as a liquid at reaction temperature and reaction pressure and
• - Has a lower density than the ionic liquid phase, so that it can be advantageously removed from the reactor head.

Especially these include saturated and unsaturated hydrocarbons, aromatic compounds, straight-chain and branched ethers, ketones, Esters, carbonates, lactones, nitriles, amides or sulfones. For example is suitable for the production of HMF in the ionic liquid 1-butyl-3-methylimidazolium methyl sulfonate, especially methyl tertiary butyl ether, Dibutyl ether or methyl isobutyl ketone, since in these neither said Carbohydrates nor the ionic liquid soluble is.

Of the Reactor brings the ionic liquid phase and the extraction phase actively or passively in contact with each other. This can for one, for example by appropriate impeller shapes, z. B. disc stirrer, and on the other by static mixing elements.

The Extraction phase with the selectively incorporated HMF becomes more advantageous Sampled at the reactor head. If necessary, this is breaking of dispersions required. This happens, for example, by known to promote coalescence, which is mechanical and / or chemically achieved by the addition of additives can be. The mechanical separation of the extraction phase of The ionic liquid phase takes place in calmed zones the reactor instead, for example on the surface of packing or other functional installations, by switching off a stirrer or in a settling tank. This can by incorporation or additions in a tubular reactor or in a Rührkessel be achieved.

Either in the microwave-assisted as well as in the conductively heated Reaction is a reactor used, the said Taking the extraction phase preferably at the reactor head and a New delivery of both fresh ionic liquid phase (ionic liquid, carbohydrates and additive) as well from the extractant. Used here per se known continuous operated reactors, such as. B. Stirred tank and tubular reactors.

The choice of reaction conditions, in particular pressure, reaction temperature, residence time in the reactor, flow rate of the extraction phase, etc. are mainly due to the physical properties of the ionic liquid phase, the extraction phase or the reactivity of the HMF to be obtained.

The Reaction can be carried out under protective gas, for. As argon or nitrogen, performed become.

The Manufacturing process allows the application of a closed Systems, which is an escape of the extraction phase into the environment prevents. About the high reaction throughput of the produced HMFs turn out to be the reactive extraction and the continuous Taking the product as highly beneficial, as well as the formation of by-products (levulinic acid, humins, coking products etc.) is prevented in the ionic liquid phase. Of the continuous operation thus leads to process simplification and to a significant reduction in the procedural and safety as well as temporal and energetic (economic) expenses.

In The dependent claims are advantageous embodiments of the method according to the invention.

The Invention will be described below with reference to embodiments be explained in more detail, without the scope of protection to limit to this.

Embodiment 1

The FIG. 1 shows by way of example the schematic representation of a per se known reactor, for carrying out the method suitable is.

A reactor room 1 is down through a bottom plate 2 and above through a cover plate 3 limited and laterally by a heating jacket 4 surround. The heating jacket 4 has an inlet 5 and a process 6 for a in the figure indicated by arrow heating means, through which the reactor space 1 is heated.

In the reactor room 1 There is a rotating agitator 7 with stirring blades 8th and in the lower reactor area a vertical perforated plate 9 ,

In the bottom plate 2 and in the cover plate 3 are two nozzles each 10 . 11 respectively. 12 . 13 arranged for the inlet and outlet of the ionic liquid phase or extraction phase.

The ionic liquid phase and the extraction phase are preferably contacted in countercurrent, ie, the ionic liquid phase is through the nozzle 12 or 13 through the cover plate 3 filled and collected in the lower reactor area. At the same time the extraction phase from below over the neck 10 or 11 through the bottom plate 2 added in countercurrent. With the stirrer 7 ionic liquid phase and extraction phase are mixed for better contacting. As a result of this reaction, 5-hydroxymethylfurfural (HMF) formed in the ionic liquid phase accumulates in the extraction phase and, together with the latter, passes through the nozzle 13 or 12 up from the reactor room 1 dissipated. The rotational speed of the agitator is chosen so that a continuous operation for discharging the HMF is made possible.

To carry out the embodiments described below, there is the reactor space 1 from a vertically arranged glass tube with a height of 40 cm and a diameter of 8 cm.

Embodiment 2:

In the above and through the heating jacket 4 heated to 80 ° C glass tube (reactor space 1 ), in which there is a mixture consisting of 5% fructose in 1 kg of 1-butyl-3-methylimidazoliummethylsulfonat (ionic liquid phase), is passed from below (nozzle 10 in the bottom plate 2 ) continuously through the perforated plate 9 Methyltertiärbutylether as extractant. At the flow contact of the continuously filled extractant with the in the reaction space 1 located ionic liquid phase (said mixture of fructose and 1-butyl-3-methylimidazoliummethylsulfonat), the resulting HMF passes into the extractant, which passes through the cover plate 3 through (neck 12 ) is taken continuously. At the reactor bottom (nozzle 11 in the bottom plate 2 ) dissipates the ionic liquid phase freed from fructose and HMF. According to this removal is from above (neck 13 in the cover plate 3 ) ionic liquid phase (said mixture of ionic liquid and fructose refilled.

The average residence time of the ionic liquid phase in the reactor space 1 is 1 h. From the the reactor room 1 removed HMF-containing extraction phase, the solvent, for example, by a not shown for reasons of clarity in the drawing rotary evaporator removed.

It results in a yield of 92%, based on the fructose, at a purity> 98%. This corresponds to a reactor power of 33 g HMF / h.

Embodiments 3-17:

According to the procedure described in Example 2, to recover HMF as further examples (see Table 1), a sugar solution in an ionic liquid is now heated to the temperature indicated in Table 1 by means of microwave irradiation, and extracted continuously with methyl tert-butyl ether. Table 1: Process conditions and reactor performance for Embodiments 2-17 embodiment Ionic liquid zuckerart Conc. [%] T [° C] Reactor power [g / h] 2 1-butyl-3-methylimidazoliummethylsulfonat fructose 5 80 33 3 1-butyl-3-methylimidazoliummethylsulfonat fructose 8th 80 50 4 1-butyl-3-methylimidazoliummethylsulfonat fructose 15 80 80 5 1-butyl-3-methylimidazoliummethylsulfonat fructose 20 80 97 6 1-butyl-3-methylimidazoliummethylsulfonat fructose 25 80 120 7 1-butyl-3-methylimidazoliummethylsulfonat fructose 5 100 23 8th 1-butyl-3-methylimidazoliummethylsulfonat fructose 8th 100 60 9 1-butyl-3-methylimidazoliummethylsulfonat fructose 15 100 102 10 1-butyl-3-methylimidazoliummethylsulfonat fructose 20 100 140 11 1-butyl-3-methylimidazoliummethylsulfonat sucrose 5 80 19 12 1-butyl-3-methylimidazoliummethylsulfonat sucrose 25 80 210 13 1-butyl-3-methylimidazoliummethylsulfonat inulin 5 80 33 14 1-allyl-3-methylimidazoliumbromid fructose 5 80 32 15 1-ethyl-3-methylimidazolium p-toluenesulfonate fructose 5 80 3 16 1-butyl-3-methylimidazoliumtrifluoromethylsulfonat fructose 5 80 7 17 1-butyl-3-methylimidazoliummethylsulfonat fructose 5 60 25

Embodiment 18:

According to Embodiment 2, a 15% fructose solution in the ionic liquid 1-butyl-3-methylimidazoliummethylsulfonat with the addition of HCl (1 mol%) as an additive in a continuously operated jacket-heated reactor (see Figure) heated to 80 ° C and extracted continuously with methyl tert-butyl ether. The mean residence time of the ionic liquid phase in the reactor is 1 h.

The HMF-containing extraction phase is after the overflow at the reactor head (cover plate 3 ) and the solvent is again removed from the product on said rotary evaporator.

It results in a yield of 88% based on the fructose, at a purity> 98%. This corresponds to a reactor power of 92 g HMF / h.

Embodiment 19:

Corresponding Embodiment 2 becomes a 5% fructose solution in the ionic liquid 1-butyl-3-methylimidazoliummethylsulfonat with the addition of water (1 mol%) as an additive in a continuous operated jacket-heated reactor (see Figure) to 80 ° C. heated and continuously with methyl tert-butyl ether extracted. The mean residence time of the ionic liquid phase in the reactor is 1 h.

The HMF-containing extraction phase is after the overflow at the reactor head (cover plate 3 ) and the solvent is again removed from the product on said rotary evaporator.

It results in a yield of 85% based on the fructose, at a purity> 98%. This corresponds to a reactor power of 30 g HMF / h.

Embodiment 20:

According to embodiment 2, a 5% strength fructose solution in the ionic liquid N-butyl-N-methylpyrrolidinium chloride is heated to 80 ° C. with addition of water (10%) as an additive in a continuously operated, shell-heated reactor (see Figure) and with methyl tert-butyl ether extracted continuously. The mean residence time of the ionic liquid phase in the reactor is 1 h. The HMF-containing extraction phase is after the overflow at the reactor head (cover plate 3 ) and the solvent is again removed from the product on said rotary evaporator. This results in a yield of 26% based on the fructose used, with a purity> 98%. This corresponds to a reactor power of 9 g HMF / h.

Embodiment 21:

According to Embodiment 2, a 5% fructose solution in the ionic liquid 1-hexyl-3-methylimidazolium chloride is heated to 80 ° C. with addition of water (6%) as an additive in a continuously operated shell-heated reactor (see Figure) and with methyl tert-butyl ether extracted continuously. The mean residence time of the ionic liquid phase in the reactor is 1 h. The HMF-containing extraction phase is after the overflow at the reactor head (cover plate 3 ) and the solvent is again removed from the product on said rotary evaporator.

It results in a yield of 41% based on the fructose, at a purity> 98%. This corresponds to a reactor power of 14 g HMF / h.

1

reactor chamber

2

baseplate

3

cover plate

4

heating jacket

5

Intake

6

procedure

7

agitator

8th

stirring blades

9

perforated plate

10 11

Support

12 13

Support

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

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Claims (37)

A process for the preparation of 5-hydroxymethylfurfural (HMF) by thermal reaction of carbohydrates, in particular monosaccharides, in an ionic liquid and discharging the 5-hydroxymethylfurfural formed in it by means of an extractant, characterized in that as extracting agent in the ionic liquid or not poorly soluble liquid, such as dibutyl ether, the ionic liquid phase with the carbohydrates contained therein in a heated above room temperature reaction zone for the purpose of generating a separated from the ionic liquid phase extraction phase with lower density than that of the ionic liquid phase for continuous discharge of the extractant in the Reactive extraction of dissolved 5-hydroxymethylfurfurally contacted. Process according to claim 1, characterized characterized in that the extractant is the ionic liquid phase flows through with the carbohydrates contained therein. Process according to claim 1, characterized characterized in that the extractant at the ionic liquid phase with the carbohydrates it flows past and while contacting the ionic liquid phase. A method according to claim 1, characterized in that the ionic liquid phase by uptake, such as solution or suspension, the carbohydrates in the ionic liquid and optionally with the addition of one or more additives, such as Bronsted acids (for example, water, hydrochloric acid, sulfuric acid, phosphoric acid , HBF ₄ , HPF ₆ , CF ₃ SO ₃ H, [(CF ₃ SO ₂ ) ₂ ] NH, acetic acid, levulinic acid), their anhydrides (for example acetic anhydride, trifluoromethanesulfonic anhydride, trifluoroacetic anhydride), Lewis acids (for example aluminum trichlorides, other metal halides) , Coagulation aids and viscosity regulators. A method according to claim 4, characterized characterized in that the ionic liquid phase immediately is formed in the reaction zone. A method according to claim 4, characterized characterized in that the ionic liquid phase already is introduced as a mixture in the reaction zone. A method according to claim 4, characterized characterized in that the carbohydrates as polymeric, dimeric or monomeric sucrose or as their mixture in the ionic liquid be introduced. A method according to claim 4, characterized characterized in that the carbohydrates as starch, cellulose, inulin, Fructose, glucose or sucrose or as their mixture in the ionic liquid are introduced. A method according to claim 4, characterized characterized in that the carbohydrates as part of a natural substance as well as in the form of crushed plant parts in the ionic Liquid to be suspended. A method according to claim 4, characterized characterized in that the carbohydrates as part of a natural substance and as a solid or liquid extract by solution or suspension added in the ionic liquid become. Process according to claim 7, characterized characterized in that the dissolved in the ionic liquid phase or suspended monosaccharides in situ by the cleavage of a Oligo- or polysaccharides, such as sucrose, starch, inulin, or carbohydrate-containing vegetable raw materials, eg. B. chicory roots, straw, Wood, corn or sugar beets. Method according to one or more of claims 1 to 11, characterized in that the ionic liquid phase carbohydrates in one concentration between 5 and 70 percent by weight, based on one hexose equivalent, be added. Process according to claim 1, characterized characterized in that the ionic liquid phase, which from the Extraction agent is contacted, flowing from a single ionic liquid. A method according to claim 1, characterized in that the ionic liquid phase, which contacted by the extractant, is formed from a plurality of ionic liquids. Process according to claim 1, characterized characterized in that the ionic liquid phase has a melting point less than 150 ° C, preferably less than 50 ° C, has. A method according to claim 13 or 14, characterized in that the or at least one of the ionic Liquids at a pressure of 1 bar a melting point less than 150 ° C, preferably less than 50 ° C, has. A method according to claim 1, characterized in that the ionic liquid is formed by a compound consisting of a cation [RX] ⁺ and an anion [B] ^- , wherein: R: a hydrogen atom, a "C _1-10 alkyl "," C _5-10 aryl "or" C _2-10 -alkenyl ", X: at least one hetero atom and an organic substituted, unsubstituted aliphatic, aromatic, alicyclic or heterocyclic compound, such as a sulfur, nitrogen or Phosphorus compound, wherein the heteroatom may be primary, secondary or tertiary, for example 1-alkylimidazole, 1,2-dialkylimidazole, 1-alkenylimidazole, 1-alkoxyimidazole, imidazole, 1-arylimidazole, 2-alkylimidazole, ammonia, Quinoline, isoquinoline, pyridine, alkylpyridine, pyrrolidine, N-alkylpyrrolidine, N-alkenylpyrrolidine, N-alkoxypyrrolidine, morpholine, N-alkylmorpholine, N-alkenylmorpholine, N-alkoxymorpholine, acridine, azepine, benzimidazole, benzoquinoline, benzothiazole, benzothiazoline, benzothiophene en, benzotriazole, benzoxazole, benzthiazole, carbazole, quinazole, quinazoline, quinoxaline, quinuclidine, caffeine, dithiane, furazane, imidazolidine, imidazoline, indazole, indole, indoline, indolizine, isoindoline, isothiazole, isoxazole, melamine, naphthyridine, oxadiazole, oxazole, Phenantridine, phenanthroline, phenazine, phenothiazine, phenoxadine, phthalazine, piperazine, piperidine, pteridine, purine, pyrazine, pyrazolidine, pyrazoline, pyridazine, pyrimidine, pyrrole, pyrroline, pyryl, tetrazole, thiadiazine, thiazine, thiomorpholine, thionaphthene, thiophene, triazine, Trithian, Trophan, etc., and may be represented by the formulas VI and VII: PY ¹ Y ² Y ³ (VI) NY ¹ Y ² Y ³ , (VII) in which Y ¹ , Y ² and Y ^{3 are} hydrogen, "C _1-10 -alkyl", "C _2-10 -alkenyl", "C _5-10 -aryl" and may be the same or different from each other, and B: F ^-, Cl ^-, Br ^-, I ^-, OH ^- NO ₃ ^-, BF ₄ ^-, PF ₆ ^-, FeCl ₄ ^-, ZnCl ₃ ^-, SnCl ₅ ^-, AsF ₆ ^-, SbF ₆ ^-, AlCl ₄ ^-, CF ₃ CO ₂ ^- , NiCl ₃ ^- , ClO ₄ ^- , [(CF ₃ SO ₂ ) ₂ N] ^- , CF ₃ SO ₃ ^- , CN ^- , (CN) ₂ N ^- , (CF ₃ SO ₂ ) ₃ C ^- , (CF ₃ ) ₂ PF ₄ ^- , (CF ₃ ) ₃ PF ₃ ^- , (CF ₃ ) ₅ PF ^- , (CF ₃ ) ₆ P ^- , SF ₅ CF ₂ SO ₃ ^- , SF ₅ CHFCF ₂ SO ₃ ^- , CF ₃ CF ₂ (CF ₃ ) ₂ CO ^- , (CF ₃ SO ₂ ) ₂ CH ^- , (SF ₅ ) ₃ C ^- , [O (CF ₃ ) ₂ C ₂ CF ₃ ) ₂ O] ₂ PO ^- , [H (CF ₃ SO ₃ ) ₂ ] C ^- , (CF ₃ ) ₂ N ^- , B (CN) ₄ ^- , (C ₂ F ₅ ) ₂ P (O) O ^- , (C ₂ F ₅ ) ₃ PF ₃ ^- , (C ₃ F ₇ ) ₃ PF ₃ ^- , (C ₄ F ₉ ) ₃ PF ₃ ^- , Co (CO) ₄ ^- , HSO ₃ ^- , HSO ₄ ^- , H ₂ PO ₄ ^- , HPO ₄ ^{2 -} , BCl ₄ ^- , SO ₄ ^2- , CO ₃ ^2- , "C _5-10 -aryl" sulfonate, "C _1-10 -alkyl" sulfonate, "C _1-10 -al Kyl "sulfate, di" C _1-10 alkyl "phosphate," C _1-10 alkyl "phosphonate," C _5-10 aryl "phosphonate," C _2-10 alkenyl "sulfonate," C _2-10 alkenyl carbonate, C _2-10 alkenyl phosphonate, C _5-10 aryl sulphate, C _2-10 alkenyl sulphate, bis (perfluoro C _1-10 alkylsulphonyl) amide, Bis (perfluoro "C _5-10 aryl" sulfonyl) amide, bis (perfluoro "C _2-10 alkenyl" sulfonyl) amide, "C _1-10 alkyl" carbonate, "C _5-10 aryl" carbonate, "C _1-10 alkyl" carboxylate, "C _2-10 alkenyl" carboxylate or "C _5-10 aryl" carboxylate. A method according to claim 4, characterized characterized in that the additives in a concentration of 0 to 10 weight percent, preferably 0 to 2 weight percent, based to the ionic liquid phase can be added. Process according to claim 1, characterized characterized in that the temperature in the reaction zone in a Range between 50 ° and 150 ° C, preferably between 70 ° C and 90 ° C, lies. Process according to claim 1, characterized characterized in that the pressure in the reaction zone is between 0.5 bar and 80 bar, preferably between 0.8 bar and 5 bar, at best at 1 bar, is set. Process according to claim 1, characterized characterized in that the extraction phase is the ionic liquid phase, especially under flow, continuously contacted. Method according to claim 21, characterized that the extraction phase and the ionic liquid phase in cocurrent or countercurrent flow with constant flow rates run through the reaction zone, wherein the contacting times in the reaction zone are preferably coordinated so that a consistently high extraction efficiency of the extraction phase is respected. Process according to claim 1, characterized characterized in that the extraction phase consists of one or more organic solvents, such as saturated and unsaturated hydrocarbons, aromatic compounds, straight-chain and branched ethers, ketones, esters, carbonates, lactones, Nitriles, amides or sulphones (for example methyl tert-butyl ether, Dibutyl ether, methyl isobutyl ketone, 1,2-dichloroethane, 1,2-dimethoxyethane, Acetone, acetonitrile, benzene, benzonitrile, bromoform, butylbenzene, Butylhydroxytoluene, butyrolactone, chloroform, cyclohexane, cyclohexene, Dibutyl carbonate, dichloromethane, diethyl carbonate, diethyl ether, bis (2-methoxyethyl) ether, Dimethoxyethane, dimethylacetamide, dimethyl carbonate, dimethyl ether, Dimethylformamide, dimethylsulfone, dimethyl sulfoxide, dioxane, dioxolane, Acetic acid, ethanol, ethylene carbonate, ethyl acetate, ethylbenzene, Ethylene glycol, ethyl formate, ethyl methyl carbonate, ethyl methyl ketone, Heptanes, hexanes, mesitylene, methanol, methyl formate, methyl propionate, Methyltetrahydrofuran, xylenes, nitrobenzenes, nitromethane, N-methylpyrolidone, Octanes, pentanes, propanols, propylbenzenes, propylene carbonate, pyridine, Sulfur dioxide, carbon disulfide, sulfolane, t-butyl alcohol, carbon tetrachloride, Tetrahydrofuran, tetramethylenesulfone, thiophene, toluene, water) or subcritical and supercritical fluids. Process according to claims 1, 19 and 20, characterized in that the boiling point of the extraction phase at a given pressure higher than the temperature in the reaction zone is and between 50 ° C and 200 ° C, preferably between 80 ° C and 140 ° C, lies. Process according to claim 1, characterized characterized in that for carrying it out a reactor, for example a tubular reactor or a stirred tank, is used. Method according to claim 25, characterized in that that the removal of the extraction phase as well as the feed of carbohydrates, in particular monosaccharides, additives and ionic liquid or ionic liquid phase take place at the head of the reactor. Method according to claim 25, characterized in that that intensive mixing takes place in the reactor. Method according to Claim 27, characterized that the mixing active by appropriate impeller shapes, for example by means of disc stirrer. Method according to Claim 27, characterized that mixing is done passively by static mixing elements. Method according to claim 25, characterized in that that in the reactor, a mechanical separation of the extraction phase from the ionic liquid phase in calm flow zones takes place, for example, on constructive elements in or outside of the reactor, as on the surface of packing, or by switching off an agitator. Method according to claim 25, characterized in that that the ionic liquid phase and / or the extraction phase be heated by a tempering device. Method according to claim 31, characterized in that that the heating in the reactor conductively, for example by means of Steam, by heating fluid, or by heating tapes, he follows. Method according to claim 31, characterized in that that the heating in the reactor under irradiation of high-frequency waves, for example, by using a microwave oven occurs. Process according to claims 25 and 31, characterized in that the ionic liquid phase and / or the extraction phase prior to introduction into the reactor, for example Conductive or by irradiation of high frequency waves, preheated become. Method according to claim 25, characterized in that that this is operated in a closed reactor system. Method according to claim 1, characterized in that that the reaction in the reaction zone under inert gas, for example Argon or nitrogen, is operated. A method according to claim 1, characterized in that the extraction phase after removal of HMF is returned to the reaction zone.