DE102004047722B4 - Process for isolating and separating carbohydrates from aqueous media and use of ionic liquids for the extraction of carbohydrates - Google Patents

Abstract

A process for isolating carbohydrates from aqueous media, characterized in that
(a) carrying out an extraction of the aqueous medium with an organic solvent or an ionic liquid, the organic solvent or the ionic liquid containing an amine which is used in a molar amine-sugar ratio of 2-25,
(b) extracting the carbohydrate (s) with water from the organic solvent or ionic liquid.

Description

The The present invention relates to a method of isolation and separation of carbohydrates, in particular of monosaccharides, disaccharides and / or oligosaccharides, from aqueous Media in which one uses an organic solvent or an ionic Liquid, each containing an amine, performs an extraction and the saccharide (s) are then re-extracted isolated against water. The invention also relates to the use of ionic liquids for the extraction of carbohydrates.

The Processing of valuable substances from a reaction solution, from Raw or waste materials usually make up a large proportion the procedural costs. Because of this, people often try preferably reach high concentrations around the individual process sections preferably effective. This is not always possible in individual cases, e.g. in the extraction of ingredients from renewable raw materials or from biotechnological production processes. Difficulties occur even if it is very soluble in water Substances like carbohydrates should be extracted from aqueous solutions, without change the external condition a e.g. selective extraction after pH adjustment with organic solvents possible is.

In For the past 30 years, interest has been increasing, renewable resources to use industrially. Carbohydrates are particularly good as Output connections, as these have the one the greatest availability and the other accessible in high purity are. An important raw material is glucose, which is worldwide in one scale of about 5 million t / a is produced. Glucose is becoming industrial produced by enzymatic hydrolysis of starch. The main applications are in the food sector, as a carbon source for industrial Fermentation and as a raw material for the synthesis of sorbitol [1].

The Recovery of carbohydrates from aqueous media (fermentation broths) provides because of the big, irregular and multivalent structure and low solubility in organic solvents a problem.

Previous Working employed mainly with the extraction of carbohydrate carboxylic acids such as gluconic acid or the lactic acid [Ref. 1-4]. Here could by adding a carrier to the organic solvent be shown that an extractive extraction of carboxylic acids is possible. Kida et al. demonstrated the selective transport of monosaccharides a bulker membrane with the aid of a carrier. something similar Ryan et al presented in their work. They extracted different ones Sugar with the help of a complex to be synthesized cyclic Receptor. The selective transport of monosaccharides by a Lipid-bilayer membrane using phenylboronic acid as carrier Westmark et. al. In this work could Monosaccharides from the aqueous Phase are separated. The disadvantage of this work is the one in high expenditure of time (partly up to 4 days) and on the other hand at the low concentration of the recovered substances [Ref. 5-7].

task The present invention is therefore a simple and efficient Process for the isolation and / or separation of carbohydrates aqueous Provide media that is preferably feasible within a short period of time.

to solution The object is the method of claims 1 to 14 or the use according to the claims 15 to 17 proposed.

• (a) eine Extraktion des wässrigen Mediums mit einem organischen Lösungsmittel oder einer ionischen Flüssigkeit durchführt, wobei das organische Lösungsmittel oder die ionische Flüssigkeit ein primäres, sekundäres und/oder tertiäres Amin enthält, das man in einem molaren Amin-Zucker-Verhältnis von 2-25 einsetzt, und man
• (b) aus dem orgänischen Lösungsmittel oder der ionischen Flüssigkeit das/die Kohlenhydrat(e) mit Wasser extrahiert.

The invention relates to a method for isolating carbohydrates (saccharides) from aqueous media, wherein

• (a) carrying out an extraction of the aqueous medium with an organic solvent or an ionic liquid, wherein the organic solvent or the ionic liquid contains a primary, secondary and / or tertiary amine which is obtained in a molar amine-sugar ratio of 2 25 uses, and one
• (b) extracting the carbohydrate (s) with water from the organic solvent or ionic liquid.

at the carbohydrate or carbohydrates are preferably a monosaccharide / monosaccharide and / or a disaccharide / disaccharide and / or an oligosaccharide / oligosaccharide.

at the aqueous Medium is preferably an aqueous solution, but it can also be a slurry or raw extract.

Possibly subjecting the aqueous solution obtained in step (b) to further purification and / or Separation, for example by chromatography, membrane processes, Evaporation or adsorption.

According to one particular embodiment subjecting the aqueous solution obtained in step (b) again to the abovementioned inventive method, to achieve further separation / purification.

advantageously, the water is removed from the aqueous solution obtained in step (b). suitable Methods, e.g. Thin film evaporation, Rotary evaporation, spray drying and lyophilization are well known to those skilled in the art.

The The aforementioned method is carried out at a temperature of up to about 40 ° C, like e.g. at about 20 ° C, about 30 ° C or about 40 ° C, carried out. A temperature of 40 ° C is advantageous. The selectivity increases due to low temperatures, so that a temperature of 20 ° C preferred becomes.

The organic solvents is selected from the group of unbranched aliphatics, aliphatic alcohols, ethers, Aromatics or mixtures thereof selected.

The Group of unbranched aliphatics includes, for example, n-hexane, n-heptane, n-decane, n-pentane, n-butane, isooctane, octadecane, 2-methylpentane, Hexadecane and Heptadecan.

Also branched aliphatics and cycloaliphatic, e.g. Cyclohexane come as well as cyclic ketones (e.g., cyclohexanone). the Professional are appropriate solvents well known from the aforementioned classes, and their suitability in the context the method according to the invention is easy to check.

aliphatic Alcohols are, for example, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, pentanol, hexanol, heptanol, Octanol, methanol, 2-octanol, 3-octanol, isoamyl alcohol and isooctanol including all isoforms.

ether are, for example, dimethyl ether, diethyl ether, dipropyl ether, Dibutyl ether, dipentyl ether, dihexyl ether, dibenzyl ether, n-butyl ethyl ether, Diisopropyl ether, diisoamyl ether, including all in relation to the Alkyl radical conceivable isoforms. Also asymmetric ethers come in Consider such as Methyl ethyl ether, methyl propyl ether, methyl butyl ether, Ethyl propyl ether, ethyl butyl ether, tert. Butyl ethyl ether, also including all isoforms conceivable with respect to the alkyl radical, such as e.g. tert-butyl methyl ether (MTBE).

aromatic Hydrocarbons contemplated herein are toluene, p-xylene, m-xylene and o-xylene.

Suitable according to the invention are also perfluorinated hydrocarbons, where their suitability in the context of the method according to the invention easily checked by a specialist.

Especially come as organic solvents due to their availability and practicability of n-butanol, MTBE, n-hexane or toluene in question, but are not limited thereto.

The Invention relates according to a inventive alternative the use of ionic liquids for the extraction of carbohydrates, preferably monosaccharides and / or disaccharides, from aqueous Media, in particular using the method according to the invention described herein, the ionic liquid a primary, secondary and / or tertiary Contains amine.

At low temperatures (<100 ° C), ionic liquids are melting salts that are a novel class of solvents with non-molecular, ionic character. Although first representatives have been known since 1914, ionic liquids have been intensively studied as solvents for chemical reactions only in the last 15 years. Ionic liquids have no measurable vapor pressure. This is a great advantage from a procedural point of view, since in this way the distillative separation of a reaction mixture is possible as an effective method for product separation. The known problems of azeotrope formation between solvent and products do not occur. Ionic liquids are temperature stable up to over 200 ° C. By a suitable choice of cations and anions, a stepwise adjustment of the polarity and thus a matching of the solubility properties is possible. The spectrum ranges from water-miscible ionic liquids through water-immiscible to water-soluble to those that form two phases even with organic solvents. Ionic liquids that can be used in the present invention are mentioned, for example, in the publications Ref 9-13, to which reference is expressly made herein. Furthermore, reference is made to the databases of Merck (www.ionicliquids-merck.de) and Solvent Ionnovation (www.solvent-innovation.com).

In the context of the present invention are those ionic liquids into consideration, which are not or only slightly miscible with water and which are liquid in the above-mentioned temperature range, preferably at about 40 ° C. Preference is given to ionic liquids (IL), especially based on the N-alkylimidazolium cation [Ref. 8th]. Exemplary representatives are 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (BMIM [(CF ₃ SO ₂ ) ₂ N]), 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide ([ EMIM] [(CF ₃ SO ₂ ) ₂ N]), 1,10-di (4'-methyl-imidazolium) -decanyl-bis (trifluoromethylsulfonyl) imide ([(MIM) ₂ Dec] [(CF ₃ SO ₂ ) ₂ N]), 1-butyl-3-methyl-imidazolium hexafluorophosphate ([BMIM] [PF ₆ ]), Terrasail ^™ (from Sachem, Inc., Austin (TX), USA), and mixtures thereof, where BMIM [( CF ₃ SO ₂ ) ₂ N], as well as mixtures thereof are particularly preferred.

in the Framework of the method according to the invention it is important that the carriers (amines) are completely in the ionic liquid to solve. Furthermore, the usual Conditions for an extraction, i. good phase separation and immiscibility with water, from the ionic liquid to fulfill.

at the amine used is an alicyclic amine, an aliphatic amine or a mixture thereof. This means, that one or more amines are used, which are amines of the same type (e.g., primary Amines) or various types (e.g., primary and secondary amines) can act.

in the Framework of the method according to the invention used primary Close amines alicyclic primary Amines (such as cyclooctylamine, cyclohexylamine, cyclopentylamine, Cyclopropylamine and cycloheptylamine), aliphatic primary amines (such as 2-aminooctane, 2-aminoheptane, dodecylamine, laurylamine, octylamine, butylamine, ethylamine, Hexylamine and 2-pentylamine) or mixtures thereof. Secondary amines include amines such as dicyclohexylamine, dibenzylamine, dibutylamine, diethylamine, diisopropylamine, Dimethylamine, N-methylbutylamine or N-methylcyclohexylamine as well Mixtures thereof. tertiary Close amines Amines such as trioctylamine, tridodecylamine, tributylamine, triethylamine, Trimethylamine, N, N-dimethylcyclohexylamine, N-methyldioctylamine, N, N-dimethylisopropylamine or N, N-dimethyloctylamine, as well as mixtures thereof. It come also mixtures of primary, secondary and / or tertiary Amines under consideration.

at execution the method according to the invention you put the primary Amine in a molar amine-sugar ratio of 2-25 (i.e., 1 mol Sugar, 2 moles of amine, etc.). The actual amounts used vary depending on the solvent and carrier (amine). The individual conditions are exemplified in the following Table 4 summarized.

Should the amount of carbohydrate present in the aqueous phase is unknown so it is necessary by means of suitable analytical methods such as. HPLC to determine the concentration of sugar present. Prerequisite for this is the knowledge about which in the aqueous Phase carbohydrates. After that it is possible the to determine the appropriate amount of amine.

The Method of the present invention is for isolating carbohydrates from aqueous, carbohydrate-containing Media. It is also for separating monosaccharides and disaccharides suitable, as it was shown in the experiments carried out that with a suitable choice of organic solvent or ionic liquid and primary Amine and the process conditions (temperature, amine content) mono- and disaccharides extract differently into the non-aqueous phase and subsequently in the back extraction into the watery Phase. In this way, a nearly quantitative separation of the mono- and disaccharides are achieved. The expert is due to his Expertise and Skills able to perform in routine tests appropriate conditions for the preferably quantitative separation of the aqueous present in each case Medium existing mono and Determine disaccharides.

The process according to the invention can be carried out on a laboratory scale, for example using conventional separatory funnels. On a technical or industrial scale, suitable devices and apparatuses for automated liquid-liquid extraction are known to those skilled in the art. The extraction may be carried out batchwise, ie by isolating the nonaqueous extract obtained in step (a), or continuously, ie with immediate further processing of the non-aqueous extract obtained in step (a). Particularly preferred are countercurrent processes in membrane cells, since they allow a continuous process operation. In this case, the solvent or the ionic liquid is applied to an inert membrane (supported liquid membrane) [9,10].

According to one particular embodiment According to the invention, the process can be carried out in a membrane cell, which can be operated in countercurrent and is explained in more detail in Example 6.

The The present invention will be further described by way of examples below. without limitation to be.

EXAMPLES

example 1

200 .mu.l of the organic solvent (n-butanol, MTBE, n-hexane, toluene) and the ionic liquid (BMIM [CF ₃ SO _{2) 2} N] hereinafter), hereinafter also referred to as "IL", were synthesized with 160 ul cyclooctylamine 2-aminooctane was added. The extraction was carried out in a reaction vessel. The sugar-containing (lactose, glucose, galactose) aqueous phase (0.1 mol / l) was added to the amine solvent phase and extracted at 40 ° C for 30 min in a thermoshaker. The aqueous phase was separated and injected for analysis in the HPLC (High Performance Liquid Chromatography). The experiments were carried out both with the individual substances and with the carbohydrate mixture. Furthermore, different temperatures (20 ° C, 30 ° C, 40 ° C) and pH values for extraction with BMIM [CF ₃ SO ₂ ) ₂ N] were chosen.

Around the substances again from the solvent phase recover, first became the watery Phase separated and with 1000 ul Water back-extracts the substances. This became again at 40 ° C and 1000 rpm in a thermo shaker carried out. The upper aqueous Phase was removed and injected directly into the HPLC.

Example 2

Tab. 2: Ergebnisse der Extraktion von Lactose, Glucose und Galactose mit Dicyclohexylamin und Trioctylamin

The results of the following experiments are presented in the tables and graphs reproduced below and in reference. Tab. 1: Results of the extraction of carbohydrates

Tab. 2: Results of the extraction of lactose, glucose and galactose with dicyclohexylamine and trioctylamine

The Decrease in% refers to the decrease in substance from the aqueous Phase.

The figures show a clear difference in both the choice of solvent and of the amine. While the galactose can be extracted very well with butanol, n-hexane and toluene (mixed with cyclooctylamine) from the aqueous phase, the lactose and glucose using n-butanol and MTBE (mixed with cyclooctylamine) as extractant remains in large parts back in the aqueous phase. Extraction with BMIM [(CF ₃ SO ₂ ) ₂ N] (mixed with cyclooctylamine) gives lactose, glucose and galactose almost equal proportions.

Using 2-aminooctane as carrier ( 2 ), a significantly lower amount of carbohydrates can be obtained. Here, the individual substances can be partially recovered selectively from the aqueous phase. A clear difference can be seen in the use of BMIM [(CF ₃ SO ₂ ) ₂ N] as solvent.

While through the addition of cyclooctylamine the sugars almost equally can be extracted By adding 2-aminooctane, the lactose is better extracted as the glucose and the galactose remain for the most part in the aqueous Phase back.

In 3 and 4 it is shown that there is a temperature dependence upon extraction with BMIM [(CF ₃ SO ₂ ) ₂ N] and the corresponding carriers (primary amines). The extraction of carbohydrates with cyclooctylamine as carrier shows the best extraction results at a temperature of 40 ° C. When using 2-amino octane, the differences between the individual temperatures are lower. Here at 30 ° C and 40 ° C similar results are achieved.

To recover the substances from the solvent phase, back-extraction was carried out with water. 5 shows the example of BMIM [(CF ₃ SO ₂ ) ₂ N] as a solvent (admixed with said carrier) that the substances go back into the aqueous phase.

The results clearly show that a back extraction of carbohydrates is possible. While about 15% of lactose and glucose were recovered from BMIM [(CF ₃ SO ₂ ) ₂ N with cyclooctylamine, about 60% of galactose could be back-extracted into the aqueous phase. Lower carbohydrate levels could be recovered from BMIM [(CF ₃ SO ₂ ) ₂ N] with 2-aminooctane. However, galactose reached about 25% here as well.

Example 3

The Extraction of various sugars was tested over different periods of time. About one Period of 180 minutes, the sugar content was after 5, 10, 30, 60, 120 and 180 minutes in the aqueous Phase determined. This was at 20 ° C, 30 ° C and 40 ° C performed. When suitable in the present experiment, an extraction time out of 30 and 60 minutes.

Example 4

Extraction of further mono- and disaccharides

• - < 10%
• + 10-30%
• + + 30-70% aus der Wasserphase entfernt
• + + + > 70%

Beispiel 5: Tab 4: Beispielhafte Darstellung vorteilhafter Amin-Zucker-Verhältnisse

Analysis: The analysis of the samples after the extraction of the sugars was carried out by HPLC. The decrease in the individual sugar concentrations in the aqueous phase was determined and calculated as a percentage. The analysis refers to all described experiments. Tab. 3:

• - <10%
• + 10-30%
• + + 30-70% removed from the water phase
• + + +> 70%

Example 5: Tab 4: Exemplary representation of advantageous amine-sugar ratios

Example 6:

cell membrane to carry out the method according to the invention in countercurrent.

The Filtration cell is a thin-channel module in which the liquid on both the retentate and permeate sides in a spiral channel flows along the membrane. The two plates were made by O-ring and additionally by screwing, which compress the bottom and top plate, sealed. The permeate is over pumped a peristaltic pump into the lid of the module, where it then through the spiral Channel is guided along the coated membrane. The retentate will then over one side outlet pumped out of the cell.

Around to recover the substances present in the coated membrane, is a corresponding solvent over a Piston pump pumped into the bottom of the module, where it then through the Channel guided along the membrane and pull out the substances in the membrane. The substance-containing solvents is also over a side exit out of the cell.

A preferred membrane cell of the invention is in 16 shown.

References:

• [1] Hirth, J .; Bicker, M .; Bird; H.; (2003); Chemistry Ingenieru Engineering 75, 294-298
• [2] Leviton, A .; (1949); Industrial and Engineering Chemistry 41; 1351-1357;
• [3] San Martin, M .; Pazos, C .; Coca, J .; (1992); J. Chem. Tech. Biotechnol. 54; 1-6;
• [4] Dai, Y .; King, C.J .; (1996); Ind. Eng. Chem. Res. 35; 1215-1224;
• [5] Westmark, P.R .; Gardiner, S.J .; Smith, B.D .; (1996); J. At the. Chem. Soc. 118; 11,093 to 11,100;
• [6] Kida, T .; Furue, D .; Masuyama, A .; Nakatsuji, Y .; Ikeda, I .; (1996); Chemistry Letters; 733-734;
• [7] Ryan, T.J .; Lecollinet, G .; Velasco, T .; Davis, A.P .; (2002); PNAS 99; 4863-4866.
• [8] P. Wasserscheid, W. Keim; (2000); Angew. Chem. 112, 3926-3945.
• [9] Branco, L.C., Crespo, J.G., Afonso, C.A.M .; (2002); Chem. Eur. J. 8 no. 17, 3865-3871.
• [10] Branco, L.C., Crespo, J.G., Afonso, C.A.M .; (2002); Angew. Chem. Int. Ed. 41 no. 15, 2771-2773.
• [11] Anderson, J.L. et al .; (2002); J. Am. Chem. Soc. 124, 14247-14254.
• [12] H. Zhao; (2003); Physics and Chemistry of Liquids 41 no. 6, 545-557.
• [13] D.-Q.Xu; (2003); Synthesis No. 17, 2626-2628.

Claims (16)

Process for isolating carbohydrates from aqueous media, characterized in that (a) extraction of the aqueous medium is carried out with an organic solvent or an ionic liquid, the organic solvent or the ionic liquid containing an amine which is present in a molar amine Sugar ratio of 2-25, (b) extracting the carbohydrate (s) from the organic solvent or ionic liquid with water. Method according to claim 1, characterized in that that the amine is a primary, secondary and / or tertiary Amine is. A method according to claim 1 or 2, characterized in that the carbohydrate / carbohydrates a monosaccharide / monosaccharide, a disaccharide / disaccharide and / or an oligosaccharide / oligosaccharide is / are. Process according to claims 1 to 3, characterized that the aqueous solution obtained in step (b) of a further purification and / or separation. Method according to claim 4, characterized in that that the aqueous solution obtained in step (b) again a process according to the claims 1 to 3 undergoes. Process according to claims 1 to 5, characterized that the water is removed from the aqueous solution obtained in step (b). Process according to claims 1 to 6, characterized that the process is carried out at a temperature of about 40 ° C. Process according to claims 1 to 7, characterized that the organic solvent out the group of unbranched aliphatics, aliphatic alcohols, ethers, Aromatics or mixtures thereof is selected. Method according to claim 8, characterized in that that the organic solvent n-hexane, n-heptane, n-decane, n-pentane, n-butane, isooctane, octadecane, 2-methylpentane, hexadecane, heptadecane, Cyclohexane, cyclohexanone, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, pentanol, hexanol, heptanol, octanol, methanol, 2-octanol, 3-octanol, Isoamyl alcohol, isooctanol, dimethyl ether, diethyl ether, dipropyl ether, Dibutyl ether, dipentyl ether, dihexyl ether, dibenzyl ether, n-butyl ethyl ether, Diisopropyl ether, diisoamyl ether, methyl ethyl ether, methyl propyl ether, Methyl butyl ether, ethyl propyl ether, ethyl butyl ether, tert. butyl ethyl ether, Toluene, p-xylene, m-xylene, o-xylene and / or a perfluorinated hydrocarbon. Process according to claims 1 to 7, characterized that the ionic liquid 1-Butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-ethyl-3-methylimidazolium bis (trifluoro-methylsulfonyl) imide, 1,10-di- (4'-methyl-imidazolium) -decanyl-bis (Trifluoro-methylsulfonyl) imide and / or 1-butyl-3-methyl-imidazolium hexafluorophosphate is. Process according to claims 2 to 10, characterized that the amine is an alicyclic amine, an aliphatic amine or is a mixture of them. Method according to claim 11, characterized in that that the amine cyclooctylamine, cyclohexylamine, cyclopentylamine, cyclopropylamine, Cycloheptylamine, 2-aminooctane, 2-aminoheptane, Dodecylamine, laurylamine, octylamine, butylamine, ethylamine, hexylamine and 2-pentylamine, dicyclohexylamine, dibenzylamine, dibutylamine, diethylamine, Diisopropylamine, dimethylamine, N-methylbutylamine, N-methylcyclohexylamine, Trioctylamine, tridodecylamine, tributylamine, triethylamine, trimethylamine, N, N-dimethylcyclohexylamine, N-methyldioctylamine, N, N-dimethylisopropylamine and / or N, N-dimethyloctylamine. Process according to claims 1 to 12, characterized that it is a process for separating monosaccharides and disaccharides is. Use of ionic liquids for the extraction of Carbohydrates from aqueous Media, wherein the ionic liquid a primary, secondary and / or tertiary Contains amine. Use according to claim 14, characterized that the carbohydrates monosaccharides, disaccharides and / or oligosaccharides are. Use according to claim 14 or 15, characterized the extraction is a process according to claims 1 to 13.