IMPROVED 5-HYDROXYMETHYLFURFURAL PRODUCTION USING A MULTI-FLUORINATED ALCOHOL COMPOUND

Abstract

The present invention relates to a process for producing a water cleavage product, a water cleavage product thus produced, a process for producing at least one water cleavage secondary product, a water cleavage secondary product thus produced and the use of a multi-fluorinated alcohol compound for the extraction of at least one water cleavage product from an aqueous phase.

Claims

1. A process for producing a water cleavage product, comprising the following steps: a) providing at least one water cleavage compound having at least one hydroxyl group cleavable in an acid-catalyzed manner, b) acid-catalyzed cleavage of water from the at least one water cleavage compound provided in step a) in a reaction system having at least one phase, wherein the at least one phase comprises at least one multi-fluorinated alcohol compound having the structural formula I below: ##STR00007## where (i) R, R′ and R″ are mutually independently selected from the group consisting of H, aryl, alkyl, alkenyl, alkynyl, F, —CF.sub.2X, —C.sub.nF.sub.2nX, —C.sub.nF.sub.2n-2X, wherein at least one of the radicals R, R′ and R″ is other than H, aryl, alkyl, alkenyl and alkynyl, n is an integer and has values from 2 to 6 and X=H, F or Cl, or (ii) R and R′ are covalently bonded to each other and form a chain having an empirical formula which is selected from the group consisting of —C.sub.mF.sub.2m-1X, —C.sub.mF.sub.2m-2X, —C.sub.mF.sub.2m-3X, —C.sub.mF.sub.2m-4X and —C.sub.mF.sub.m-1X and where R″ is selected from the group consisting of H, aryl, alkyl, alkenyl, alkynyl, F, —CF.sub.2X, —C.sub.nF.sub.2nX and —C.sub.nF.sub.2n-2X, where n is an integer and has values from 2 to 6, where X=H, F or Cl and where m is an integer and has values from 3 to 7, or where R″ is not present if a double bond is present on the carbon atom adjacent to the OH; and c) obtaining at least one water cleavage product produced according to step b).

2. The process as claimed in claim 1, wherein the at least one water cleavage compound having at least one hydroxyl group cleavable in an acid-catalyzed manner is a carbohydrate, a carbohydrate derivative or a mixture thereof.

3. The process as claimed in claim 2, wherein the at least one carbohydrate is a compound containing hexose and/or pentose.

4. The process as claimed in claim 3, wherein the hexose and/or pentose is selected from the group consisting of fructose, glucose, arabinose and xylose.

5. The process as claimed in claim 1, wherein the multi-fluorinated alcohol compound is selected from the group consisting of 2,2,3,3,3-pentafluoropropan-1-ol, 2-allylhexafluoroisopropanol, 1H,1H-heptafluorobutan-1 -ol, 2,2,3,4,4,4-hexafluorobutan-1-ol, 2,2,3,3,4,4,5,5-octafluoropentan-1-ol, 1,1,1,3,3,3-hexafluoropropan-2-ol, 1,1,1,3,3,3-hexafluoro-2-trifluoromethylpropan-2-ol and 2,3,4,5,6-pentafluorophenol.

6. The process as claimed in claim 1, wherein the reaction system has a second phase, wherein the second phase is an aqueous phase.

7. The process as claimed in claim 1, wherein the reaction system comprises water and the at least one multi-fluorinated alcohol compound in a ratio from 30:1 to 1:30.

8. The process as claimed in claim 1, wherein the reaction system comprises at least one acid selected from the group consisting of an organic acid, an isopoly acid, a heteropoly acid, a mineral acid, a Lewis acid and a solid having at least one acidic center.

9. The process as claimed in claim 1, wherein the reaction system further comprises a salt.

10. The process as claimed in claim 1, wherein the at least one water cleavage compound is present at a concentration of 10 to 4000 mmol/L in the reaction system.

11. The process as claimed in claim 1, wherein the cleavage product obtained in step c) is 5-hydroxymethylfurfural or furfural.

12. The process as claimed in claim 1, wherein at least one of the R, R′, or R″ the aryl, alkyl, alkenyl, and alkynyl is an aryl, alkyl, alkenyl and alkynyl immobilized on a support material.

13. A process for producing at least one water cleavage conversion product, wherein the process comprises the following steps: aa) producing at least one water cleavage product by a process as claimed in claim 1, bb) chemical reaction of the at least one water cleavage product and cc) obtaining at least one water cleavage conversion product.

14. The process as claimed in claim 13, wherein the at least one water cleavage conversion product is at least one carbohydrate product, at least one carbohydrate derivative product or a mixture thereof.

15. The process as claimed in claim 14, wherein the at least one carbohydrate product, the at least one carbohydrate derivative product or the mixture thereof is oxidized catalytically in step bb).

16. The process as claimed in claim 14, wherein the at least one carbohydrate product, the at least one carbohydrate derivative product or the mixture thereof is hydrogenated catalytically in step bb).

17. The process as claimed in claim 13, wherein the at least one water cleavage conversion product is 5-hydroxymethylfurfural and is oxidized catalytically in the presence of water in step bb) to give furandicarboxylic acid or salts thereof.

18. The process as claimed in claim 13, wherein the at least one water cleavage conversion product is 5-hydroxymethylfurfural and is hydrogenated catalytically in step bb) to give dimethylfuran.

19. (canceled)

20. The process as claimed in claim 9 wherein the salt is an alkali metal salt.

21. The process as claimed in claim 1 wherein the at least one water cleavage compound is present at a concentration of 10 to 4000 mmol/L in an aqueous phase in the reaction system

Description

[0112] The present invention is illustrated by the following examples.

[0113] 1. Extraction Experiments

[0114] 1.1 HMF Extraction as a Function of NaCl at Room Temperature at a Ratio by Volume (Aqueous Phase:Organic Phase) of 1:1 v/v

[0115] 10 ml of an aqueous HMF solution (0.63 g/50 ml) are mixed at room temperature with 10 ml of hexafluoroisopropanol (HFIP). 0.05 g of NaCl (5 g/l) is added stepwise. Samples are withdrawn from the respective phases. The distribution coefficient is determined from the concentrations of HMF determined.

[00001]$\mathrm{Distribution}.Math..Math.\mathrm{coefficient}.Math..Math.D_{\mathrm{HMF}}=\frac{\left[c\left(\mathrm{HMF}\right)\right].Math.\mathrm{organic}.Math..Math.\mathrm{phase}}{\left[c\left(\mathrm{HMF}\right)\right].Math.\mathrm{aqueous}.Math..Math.\mathrm{phase}}$

[0116] Table 1 shows the distribution coefficients of HMF in water:HFIP 1:1 v/v at room temperature as a function of the amount of NaCl.

TABLE-US-00001 NaCl addition [g/l] K.sub.HMF 25 12 60 32 100 55 130 61 150 76 200 125

[0117] 1.2 Extraction of Further Substances with HFIP at Room Temperature at a Ratio by Volume of 1:1 v/v (Addition of NaCl)

[0118] For each substance to be tested in Table 2, a 1.5 mol/l solution is prepared. For the substances in Table 3, substance concentrations deviating therefrom are used (see Table 3). 5 ml of the relevant solution are mixed with 5 ml of HFIP. NaCl is added stepwise until a volume distribution of about 1:2 occurs. From the concentrations determined, the respective distribution coefficient is determined.

[0119] Table 2 shows the distribution coefficients of various substances in water:HFIP 1:1 v/v at room temperature.

TABLE-US-00002 TABLE 2 NaCl addition [g/l] Phase separation v/v K Acetone 60 1:2.8 73 Isopropanol 80 1:2.4 17 1,2-Propanediol 120 1:2.3 3 Acetoin 60 1:2.4 18 Diacetyl 80 1:2.3 17 Pentanol 100 1:2.7 53 1,5-Pentanediol 80 1:2.4 17 Methyl ethyl ketone 120 1:2 55 Glycerol 80 1:2.1 0.45 Erythritol 40 1:2.2 0.2 Glucose 40 1:2.2 0.07 Fructose 40 1:2.5 0.15 THF 80 1:2.3 83 Furan 40 1:2.7 6 Furfural 80 1:2.6 32

[0120] Table 3 shows the distribution coefficients of various substances in water:HFIP 1:1 v/v at room temperature.

TABLE-US-00003 TABLE 3 Concentration NaCl addition Phase [g/l] [g/l] separation v/v D Ethanol 10 120 1:2.3 9 Butanol 15 50 1:3.2 20 Formic acid 10 80 1:2 0.9 Levulinic acid 10 80 1:2 14

1.3 Use of Other Multi-Fluorinated Alcohol Compounds for the Extraction

[0121] For various substances, aqueous solutions at a concentration of 100 mmol/l are prepared in each case. 0.3 ml of the multi-fluorinated alcohol compound as extractant is added and mixed with 0.3 ml of the relevant substance solution (100 mmol/l) at room temperature.

[0122] When using HFIP, 180 g/l of NaCl are additionally added. From the concentrations determined, the respective distribution coefficient is determined.

[0123] Table 4 shows the distribution coefficients of HMF, furfural, acetone and n-butanol in various multi-fluorinated alcohol compounds, wherein the ratio of aqueous solution to the multi-fluorinated alcohol compound is 1:1 v/v at room temperature.

TABLE-US-00004 HFIP* NFBA PFprop AllylHFIP OFP HexFB HFB MIBK HMF 64 32 6 10 7 11 5 1 Furfural 64 37 14 32 >100 28 13 2 Acetone 61 45 19 24 24 0.6 23 3 n- 162 24 12 16 10 — — 0.02 Butanol *with 180 g/l salt addition HFIP hexafluoroisopropanol NFBA nonafluoro-tert-butyl alcohol Pfprop perfluoropropanol AllylHFIP 2-allylhexafluoroisopropanol OFP octafluoropentanol HexFB hexafluorobutanol HFB heptaflurobutanol MIBK methyl isobutyl ketone

[0124] 2. HMF Formation From Fructose with HCl (With and Without HFIP)

[0125] 2.1 Without HFIP Extraction

[0126] 4.6 ml of a fructose solution (0.39 g/10 ml) are initially charged in a 30 ml double-walled glass reactor and heated to 50° C. 5.4 ml of concentrated HCl (37%) are added with stirring. The whole reaction mixture is brought to 50° C. and the temperature and stirring are maintained over the entire course of the reaction (240 min).

[0127] Fructose conversion=49%, HMF yield=19%, HMF selectivity=39%

[0128] 2.2 With HFIP Extraction

[0129] 4.6 ml of a fructose solution (0.39 g/l, 217 mmol/l) and 10 ml of HFIP are initially charged in a 30 ml double-walled glass reactor and heated to 50° C. 5.4 ml of concentrated HCl (37%) are added with stirring. The whole reaction mixture is brought to 50° C. and the temperature and stirring are maintained over the entire course of the reaction (240 min).

[0130] Fructose conversion=74%, HMF yield=62%, HMF selectivity=84%

[0131] 3. Various Ratios of Aqueous Phase to HFIP Phase in HMF Formation with HCl

[0132] 3.1 23 ml of a fructose solution (216.6 mmol/l) and, depending on the phase ratio, 16.6 ml, 25 ml, 50 ml, 100 ml or 150 ml of HFIP are initially charged in a 300 ml glass reactor. 27 ml of HCl (37%) are added. The mixture is heated to 65° C. with vigorous stirring.

[0133] The temperature and stirring are maintained over the entire course of the reaction (38 min).

[0134] Table 5 shows the dehydration of fructose at various ratios of aqueous/HFIP phase (c(fructose)=100 mmol/l, T=65° C., HCl (21.5%, 6.5 mol/l), t=38 min).

TABLE-US-00005 TABLE 5 Phase ratio used aqueous phase:HFIP C.sub.fructose Y.sub.HMF S phase [%] [%] [%] 3:1 63 46 73 2:1 75 63 84 1:1 86 72 83 1:2 94 80 85 1:3 99 96 97 C = conversion; Y = yield; S = selectivity

[0135] 4. HMF Formation From Fructose Using Other Catalysts (With HFIP)

[0136] 4.1 Sulfuric Acid (H.sub.2SO.sub.4)

[0137] 61.8 ml of a fructose solution (121 mmol/l) and 75 ml of hexafluoroisopropanol are initially charged in a 300 ml glass reactor. 13.2 ml of H.sub.2SO.sub.4 (98%) are added. The mixture is heated to 70° C. with vigorous stirring. The temperature and stirring are maintained over the entire course of the reaction (400 min).

[0138] Fructose conversion=88%, HMF yield=66%, HMF selectivity=75%

[0139] 4.2 Amberlyst 15 (Heterogeneous Catalyst)

[0140] 1.8 g of fructose (100 mmol/l) and 18 g of NaCl (180 g/l) are dissolved in 100 ml of water. 75 ml of the fructose-NaCl solution and 75 ml of HFIP are initially charged in a 300 ml glass reactor. The heterogeneous catalyst (e.g. 1.35 g of Amberlyst 15) is added. The mixture is heated to 120° C. with vigorous stirring. The temperature and stirring are maintained over the entire course of the reaction (180 min).

[0141] Fructose Conversion=88%, HMF Yield=51%, HMF Selectivity=58%

[0142] 5. Conversion of Other Substrates Using the Example of the Carbohydrate Xylose (Acid-Catalytic Water Cleavage to Give Furfural)

[0143] 61.8 ml of a xylose solution (6.12 g/100 ml, 408 mmol/l) and 75 ml of HFIP are initially charged in a 300 ml glass reactor. 13.2 ml of H.sub.2SO.sub.4 (98%) are added. The mixture is heated to 120° C. with vigorous stirring. The temperature and stirring are maintained over the entire course of the reaction (120 min).

[0144] Xylose conversion=71%, furfural yield=53%, furfural selectivity=75%

[0145] 6. Conversion of Other Substrates Using the Example of the Carbohydrate Glucose to Give HMF

[0146] 50 ml of a glucose solution (5% by weight, 300 mmol/l), NaCl (4 g) and 50 ml of HFIP are initially charged in a 300 ml glass reactor. 0.9 g of AlCl.sub.3 are added as catalyst. The mixture is heated to 130° C. with vigorous stirring. The temperature and stirring are maintained over the entire course of the reaction (120 min).

[0147] Result:

[0148] C.sub.glucose=56%; Y.sub.fructose=25%; Y.sub.HMF=17%; S.sub.HMF=30%

[0149] 7. Conversion of Other Substrates Using the Example of D-arabinose to Give Furfural

[0150] 41.2 ml of a D-arabinose solution (404 mmol/l) and 50 ml of HFIP are initially charged in a 300 ml glass reactor. 8.8 ml of H.sub.2SO.sub.4 (96%) are added. The mixture is heated to 120° C. with vigorous stirring. The temperature and stirring are maintained over the entire course of the reaction (90 min).

[0151] Result:

[0152] C.sub.D-arabinose=71%; Y.sub.furfural=47%; S.sub.furfural=66%

[0153] 8. Conversion of Other Substrates Using the Example of 1,4-Butanediol to Give Tetrahydrofuran (THF)

[0154] 25 ml of HFIP, 16.4 ml of water, 2.5 mmol of 1,4-butanediol and 4.4 ml of 96% sulfuric acid are placed in a 160 ml stainless steel reactor. The mixture is heated to 120° C. with stirring at 420 rpm. The reaction time is 120 min.

[0155] Result:

[0156] C.sub.1,4-butanediol=100%; Y.sub.THF=89%; S.sub.THF=89%

[0157] 9. Conversion of Other Substrates Using the Example of 2,3-Butanediol to Give Methyl Ethyl Ketone (MEK)

[0158] 25 ml of HFIP, 16.4 ml of water, 2.5 mmol of 2,3-butanediol and 4.4 ml of 96% sulfuric acid are placed in a 160 ml stainless steel reactor. The mixture is heated to 120° C. with stirring at 420 rpm. The reaction time is 120 min.

[0159] Result:

[0160] C.sub.2,3-butanediol=100%; Y.sub.MEK=25%; S.sub.MEK=25%

[0161] 10. Conversion of Other Substrates Using the Example of 3-Hydroxypropionaldehyde (3-HPA) to Give Acrolein

[0162] 15 ml of HFIP, 12.6 ml of water, 1.5 mmol of 3-HPA and 2.6 ml of 96% sulfuric acid are placed in a 50 ml glass reactor. The mixture is heated to 60° C. with stirring. The reaction time is 120 min.

[0163] Result:

[0164] C.sub.3-HPA=100%; Y.sub.acrolein=36%; S.sub.acrolein=36%

[0165] 11. Use of Other Multi-Fluorinated Alcohol Compounds for Extracting HMF During the Reaction Using the Example of Nonafluoro-Tert-Butyl Alcohol (NFBA) Compared to HFIP

[0166] In each case 9.2 ml of a fructose solution (217.7 mmol/l) are mixed with 20 ml of nonafluoro-tert-butanol (NFBA) and HFIP, respectively, in a 50 ml glass reactor. 10.8 ml of HCl (37%) are added to each of these mixtures with stirring and are heated to 30° C.

[0167] The temperature and stirring are maintained over the entire course of the reaction (24 h).

[0168] Results: [0169] with HFIP: fructose conversion=29%, HMF yield=21%, HMF selectivity=72% [0170] with NFBA: fructose conversion=28%, HMF yield=19%, HMF selectivity=68%

[0171] 12. HMF Formation from Fructose in a Biphasic Mixture of OFP (Octafluoropentan-1-ol) and 1.5M HCl

[0172] 20 ml of OFP and 20 ml of 1.5M HCl are placed in a 100 ml three-necked flask equipped with reflux condenser and KPG stirrer and heated to 100° C. When the reaction temperature is reached, 0.8 ml of aqueous fructose solution (450 g/l) are metered in. The mixture is stirred at 400 rpm over the entire experimental period of 120 min.

[0173] Result:

[0174] C.sub.fructose=74%; Y.sub.HMF=45%; S.sub.HMF=61%

[0175] 13. HMF Formation from Fructose in a Biphasic Mixture of Pfprop (2,2,3,3,3-Pentafluoropropanol) and 6.5M HCl

[0176] 0.18 g of fructose and 4.2 ml of H.sub.2O are initially charged in a temperature-controlled glass reactor. 10 ml of Pfprop and 2.7 ml of HCl (37%) are added and the mixture heated to 56° C. with stirring. The reaction time is 300 min.

[0177] Result:

[0178] C.sub.fructose=42%; Y.sub.HMF=31%; S.sub.HMF=74%

[0179] 14. HMF Formation from Fructose in a Biphasic Mixture of Hfbutanol (2,2,3,3,4,4,4-Heptafluoro-1-Butanol) and 6.5M HCl

[0180] 0.18 g of fructose and 4.2 ml of H.sub.2O are initially charged in a temperature-controlled glass reactor. 10 ml of Hfbutanol and 2.7 ml of HCl (37%) are added and the mixture heated to 56° C. with stirring. The reaction time is 300 min.

[0181] Result:

[0182] C.sub.fructose=38%; Y.sub.HMF=28%; S.sub.HMF=74%

[0183] 15. Induced Phase Separation by Further Electrolytes

[0184] 5 ml of HFIP are added to 5 ml of an HMF solution (0.9 g/50 ml, 100 mmol/l) in a mixing cylinder. The mixture is thoroughly mixed at room temperature and phase separation is induced by adding 6 mmol of various salts (see Table 6). The distribution coefficient is determined from the HMF concentrations determined.

[0185] Table 6 shows K.sub.HMF and phase volume ratios of a water/HFIP system 1:1 v/v as a function of various salts (HMF solution (100 mmol/l)).

TABLE-US-00006 TABLE 6 Salt D.sub.HMF Phase volume ratio NaCl 45 1:2.5 K.sub.2HPO.sub.4 80 1:2.5 Al(NO.sub.3).sub.3 35 1:1.3 (NH.sub.4).sub.2SO.sub.4 64 1:3.2 KCl 17 1:3.2 Na.sub.2SO.sub.4 135 1:2.4 AlCl.sub.3 86 1:1.6 LiCl 37 1:3.2

[0186] 16. Experiment in the Acetone-HFIP-Water System

[0187] Apart from electrolytes, phase separation in the HFIP and water system is also caused by solvents such as acetonitrile, DMSO (dimethyl sulfoxide) and acetone, and can be used as a reaction system.

[0188] 20 ml of HFIP and 5 ml of acetone are placed in a 50 ml graduated flask and made up to 50 ml with water. This mixture is introduced into a 160 ml stainless steel reactor and 0.9 g of fructose and 2.6 g of Amberlyst 15 are added. The reactor is sealed and heated to 110° C. with stirring at 420 rpm. The reaction time is 120 min.

[0189] Result:

[0190] C.sub.fructose=70%; Y.sub.HMF=29%; S.sub.HMF=41%

[0191] 17. HMF Formation From Fructose in a Single-Phase Mixture of HFIP and Water and Also a Heterogeneous Catalyst (Amberlyst 15)

[0192] 17.1 In the Batch Reactor

[0193] 1.8 g of Amberlyst 15 are added to 100 ml of a solution consisting of 87.5% by volume HFIP, 12.5% by volume water and 1.8 g of fructose in a 225 ml double-walled glass reactor and the mixture is heated to 87° C. with stirring. The reaction temperature and stirring are maintained over the entire course of the experiment of 360 min.

[0194] The conversion and the yield and selectivity result from the decrease of the fructose concentration and the increase in the HMF concentration.

[0195] Result:

[0196] C.sub.fructose=98%; Y.sub.HMF=77%; S.sub.HMF=79%

[0197] 17.2 In the Continuous Fixed-Bed Reactor

[0198] A solution consisting of 87.5% by volume HFIP, 12.5% by volume water and 100 mmol/l fructose is pumped continuously at 0.2 ml/min via an HPLC pump through a tubular reactor via a pressure-maintaining valve into a product vessel. The 12.5 cm long and ⅜″ thick tubular reactor is placed in an adjustable oven and contains a catalyst fixed bed of 5 ml of Amberlyst 15. The oven internal temperature is set to 90° C. The set flow rate gives a residence time of the reaction mixture over the catalyst of 25 min.

[0199] Due to the continuous operation, a stationary state arises after a certain time which is reflected in constant concentrations and also corresponding values for conversion, yield and selectivity.

[0200] Result:

[0201] C.sub.fructose=99%; Y.sub.HMF=75%; S.sub.HMF=76%

[0202] 18. Oxidation of HMF in the HFIP Phase

[0203] In a 300 ml stainless steel reactor, 83 ml of HFIP, 15 ml of water, 4 g of catalyst (0.1% Au/Pt (90:10) on CeO.sub.2) and 6.4 g of NaOH are heated to 120° C. with stirring at 1200 rpm. On reaching the reaction temperature, 2 ml of an aqueous 0.5 M HMF solution is metered in and the reactor is pressurized with 20 bar oxygen. The reaction time is 240 min.

[0204] Result:

[0205] C.sub.HMF=48%; Y.sub.FDCA=3%, Y.sub.HFCA/FFCA=16%, Y.sub.FDA=16%

[0206] FDCA=2,5-furandicarboxylic acid

[0207] HFCA=5-hydroxyfurancarboxylic acid

[0208] FFCA=5-formylfurancarboxylic acid

[0209] FDA=2,5-furandialdehyde