GREEN SOLVENTS FOR CHEMICAL REACTIONS

Abstract

Use of a compound of the general formula (I), (II), (III), (IV), (V) or (VI)

##STR00001##

as solvent for chemical reactions, for recrystallizations or extractions.

Claims

1. Use of a compound of the general formula (I), (II), (III) (VI), (V) or (VI) ##STR00396## wherein R.sub.1 and R.sub.1, R.sub.21 and R.sub.21, R.sub.31 and R.sub.31 are the same and are hydrogen, a linear or branched C.sub.1 to C.sub.18 alkyl, a linear or branched C.sub.2 to C.sub.18 alkenyl, a linear or branched C to C.sub.10 alkoxy, a linear or branched C.sub.1 to C.sub.9 alkanoyloxy, a linear or branched C.sub.1 to C.sub.9 alkoxycarbonyl, aminocarbonyl, hydroxycarbonyl, a linear or branched C.sub.1 to C.sub.9 alkoxyalkyl, an unsubstituted cycloalkyl, a linear or branched C.sub.1 to C.sub.6 alkyl substituted cycloalkyl, preferably an unsubstituted cyclohexyl, an unsubstituted C.sub.6 to C.sub.12 aryl, a linear or branched C.sub.1 to C.sub.4 alkyl substituted C.sub.6 to C.sub.12 aryl, or C.sub.7 to C.sub.12 aralkyl, R.sub.2 and R.sub.2, R.sub.22 and R.sub.22, R.sub.32 and R.sub.32 are the same and are hydrogen, a linear or branched C.sub.1 to C.sub.18 alkyl, a linear or branched C.sub.1 to C.sub.9 alkoxyalkyl, or R.sub.2 and R.sub.2 form together with R.sub.1 and R.sub.1 respectively, R.sub.22 and R.sub.22 form together with R.sub.21 and R.sub.21 respectively, R.sub.32 and R.sub.32 form together with R.sub.1 and R.sub.1 respectively, a 5 or 6 membered unsaturated or saturated carbocyclic ring optionally comprising 1 or 2 oxygen atoms, X is selected from the group consisting of hydrogen, fluoro, chloro, bromo, iodo, alkoxycarbonyl, aminocarbonyl, hydroxycarbonyl, an alkanoyloxy, a linear or branched C.sub.1 to C.sub.18 alkyl, a C.sub.1 to C.sub.18 alkenyl, a linear or branched C.sub.2 to C.sub.10 alkenyl, a sulfonate and OR.sub.50, wherein R.sub.50 is selected from the group consisting of hydrogen, and a linear or branched C.sub.1 to C.sub.18 alkyl, Y is selected from the group consisting of hydrogen, fluoro, chloro, bromo, iodo, a linear or branched C.sub.1 to C.sub.18 alkyl, a C.sub.1 to C.sub.18 alkenyl, a linear or branched C.sub.2 to C.sub.10 alkenyl, a sulfonate and OR.sub.50, wherein R.sub.50 is selected from the group consisting of hydrogen, a linear or branched C.sub.1 to C.sub.18 alkyl, a linear or branched C.sub.1 to C.sub.9 alkanoyloxy, and a linear or branched C.sub.1 to C.sub.9 alkylcarbonyl, and R.sub.60 is selected from the group consisting of hydrogen, hydroxy and C.sub.1 to C.sub.18 alkoxy, and R.sub.61 is selected from the group consisting of hydrogen, hydroxy, C.sub.1 to C.sub.10 alkylsulfonyl-C.sub.1 to C.sub.5 and C.sub.1 to C.sub.18 alkyl as solvent for chemical reactions, for recrystallizations or extractions.

2. Use of compound (I), (II), (III), (IV) according to claim 1 as polar aprotic solvent, wherein compounds (I) and (II) are as defined in claim 1 and in compound (III) and in compound (IV) R.sub.50 is not hydrogen.

3. Use of the compounds (III) and (IV) according to claim 1 as polar protic solvent, wherein the compounds (III) and (IV) R.sub.50 is hydrogen or compound (V).

4. Use according to claim 1, wherein the solvent is used for chemical reactions.

5. Use according to claim 1, wherein the chemical reaction involves at least two starting compounds.

6. Use according to claim 1, wherein the solvent is used for a chemical reaction in the presence of an acid or a base, preferably a strong acid or strong base.

7. Use according to claim 1, wherein each of R.sub.2 and R.sub.2 is hydrogen.

8. Use according to claim 1, wherein R.sub.1 and R.sub.1 are hydrogen or a linear C.sub.1 to C.sub.18 alkyl, a linear C.sub.2 to C.sub.18 alkenyl, a linear C.sub.1 to C.sub.18 alkoxy, a linear or branched C.sub.1 to C.sub.9 alkanoyloxy, a linear C.sub.1 to C.sub.9 alkoxycarbonyl or a linear C.sub.1 to C.sub.9 alkoxyalkyl, preferably a linear C.sub.1 to C.sub.9 alkoxycarbonyl.

9. Use according to claim 1, wherein R.sub.1 and R.sub.1 are a branched C.sub.1 to C.sub.18 alkyl, a branched C.sub.1 to C.sub.9 alkoxyalkyl, and wherein R.sub.2 and R.sub.2 are the same and both hydrogen.

10. Use according to claim 1, wherein the chemical reaction is selected from the group consisting of the Heck reaction, alkylation reaction, hydrogenation reaction, Ullmann reaction or Ullmann coupling, Wurtz reaction, Grignard reaction, Gomberg-Bachmann reaction, Castro-Stephens coupling, Corey-House synthesis, Cassar reaction, Kumada coupling, Sonogashira coupling, Negishi coupling, Stille cross coupling, Suzuki reaction, Hiyama coupling, Buchwald-Hartwig reaction, Fukuyama coupling, Liebeskind-Srogl coupling, Solid-Phase Peptide Synthesis (SPPS), nucleophilic substitution, amidation, esterification, biginelli reaction, carbonyl addition, aza-Michael addition, Krapcho dealkoxycarbonylation, Boulton-Katritzky rearrangement, Michael addition and Beckmann rearrangement, and dehydrohalide coupling.

11. Use according to claim 1, wherein the chemical reaction is selected from the group consisting of Heck reaction, alkylation reaction, aldehyde-assisted biomass fractionation, and hydrogenation reaction.

12. Use according to claim 3, wherein the chemical reaction is selected from the group consisting of the reduction of nitro compounds, hydrogenation, halogenation, synthesis of ionic liquids, nucleophilic substitution with SN1 mechanism, elimination reaction with E1 mechanism and E2 mechanism, synthesis via SnAr mechanism, extractions of bioactive compounds and extractions of any compounds from biological sources.

13. Use according to claim 1, wherein the compound of formula (I), (II), (III), (IV), (V) or (VI) is selected from the group consisting of ##STR00397## ##STR00398## ##STR00399## ##STR00400## ##STR00401## ##STR00402## ##STR00403## ##STR00404## ##STR00405## ##STR00406## ##STR00407## ##STR00408## ##STR00409##

14. Use according to claim 1, wherein the compound of the general formula (I), (II) (III), (IV), (V) and (VI) is used as solvent in enzymatic reactions, in particular for a polycondensations for the synthesis of polyesters, or as at least one component of battery electrodes, for synthesis of metal-organic frameworks (MOFs) for preparation of electrodes, as solvent for liquid-phase exfoliations, in particular as substitute for NMP in liquid exfoliation of MoS.sub.2 particles, solvent for storage, solvent for biomass pretreatment and biomass processing, in particular for aldehyde-assisted biomass fractionation, for solid-Phase Peptide Synthesis, in particular as replacement for N,N-dimethylacetamide (DMAc) in solid-Phase Peptide Synthesis, for Microfiltration membrane preparation, component of Deep eutectic solvents.

15. Use according to claim 1, wherein the compounds of the general formula (I) or (II) are used as a replacement of N-methylpyrrolidinone, N,N-dimethylacetamide (DMAc) or N,N-dimethylformamide (DMF), 1,3-dimethyl-2-imidazolidinone (DMI) for chemical reaction, in particular for organic synthesis.

16. Use according to claim 1, wherein the compound is Diformylxylose (DFX) ##STR00410##

17. Method for producing a compound of the general formula (I), (II), (III) (VI), (V) or (VI) ##STR00411## wherein R.sub.1 and R.sub.1, R.sub.21 and R.sub.21, R.sub.31 and R.sub.31 are the same and are hydrogen, a linear or branched C.sub.1 to C.sub.18 alkyl, a linear or branched C.sub.2 to C.sub.18 alkenyl, a linear or branched C.sub.1 to C.sub.10 alkoxy, a linear or branched C.sub.1 to C.sub.9 alkanoyloxy, a linear or branched C.sub.1 to C.sub.9 alkoxycarbonyl, aminocarbonyl, hydroxycarbonyl, a linear or branched C.sub.1 to C.sub.9 alkoxyalkyl, an unsubstituted cycloalkyl, a linear or branched C.sub.1 to C.sub.6 alkyl substituted cycloalkyl, preferably an unsubstituted cyclohexyl, an unsubstituted C.sub.6 to C.sub.12 aryl, a linear or branched C.sub.1 to C.sub.4 alkyl substituted C.sub.6 to C.sub.12 aryl, or C.sub.7 to C.sub.12 aralkyl, R.sub.2 and R.sub.2, R.sub.22 and R.sub.22, R.sub.32 and R.sub.32 are the same and are hydrogen, a linear or branched C.sub.1 to C.sub.18 alkyl, a linear or branched C.sub.1 to C.sub.9 alkoxyalkyl, or R.sub.2 and R.sub.2 form together with R.sub.1 and R.sub.1 respectively, R.sub.22 and R.sub.22 form together with R.sub.21 and R.sub.21 respectively, R.sub.32 and R.sub.32 form together with R.sub.1 and R.sub.1 respectively, a 5 or 6 membered unsaturated or saturated carbocyclic ring optionally comprising 1 or 2 oxygen atoms, X is selected from the group consisting of hydrogen, fluoro, chloro, bromo, iodo, alkanoyloxy, alkoxycarbonyl, aminocarbonyl, hydroxycarbonyl, a linear or branched C.sub.1 to C.sub.18 alkyl, a C.sub.1 to C.sub.18 alkenyl, a linear or branched C.sub.2 to C.sub.10 alkenyl, a sulfonate and OR.sub.50, wherein R.sub.50 is selected from the group consisting of hydrogen, a linear or branched C.sub.1 to C.sub.18 alkyl, Y is selected from the group consisting of hydrogen, fluoro, chloro, bromo, iodo, a linear or branched C.sub.1 to C.sub.18 alkyl, a C.sub.1 to C.sub.18 alkenyl, a linear or branched C.sub.2 to C.sub.10 alkenyl, a sulfonate and OR.sub.50, wherein R.sub.50 is selected from the group consisting of hydrogen, a linear or branched C.sub.1 to C.sub.18 alkyl, and a linear or branched C.sub.1 to C.sub.9 alkylcarbonyl, R.sub.60 is selected from the group consisting of hydrogen, hydroxy and C.sub.1 to C.sub.18 alkoxy, and R.sub.61 is selected from the group consisting of hydrogen, hydroxy, C.sub.1 to C.sub.10 alkylsulfonyl-C.sub.1 to C.sub.5 and C.sub.1 to C.sub.18 alkyl, involving the reaction step of reacting D-xylose or D-glucose with an aldehyde of the general formula (XXX) R.sub.11CHO, (XXXI) R.sub.21CHO or (XXXII) R.sub.31CHO, or a ketone of the general formula (XXIII) R.sub.11COR.sub.12, (XXIV) R.sub.21COR.sub.22 or (XXV) R.sub.31COR.sub.32 or a cyclic or linear carbonate and R.sub.11, R.sub.12, R.sub.21, R.sub.22, R.sub.31 and R.sub.32 have the same definition as above, in the presence of H.sub.2SO.sub.4 using 2-methyltetrahydrofuran (2-Me-THF) as a solvent.

18. Method according to claim 17, wherein the aldehyde is paraformaldehyde.

19. Method according to claim 17 comprising the steps of a) providing a composition containing D-xylose or D-glucose, an aldehyde and 2-methyltetrahydrofuran (2-Me-THF), b) adding H.sub.2SO.sub.4 to the composition of step a) c) heating the composition of step b), preferably to a temperature between 60 and 120? C.

20. Method according to claim 17, comprising the steps of d) extracting the compound of the general formula (I), (II), (III) (VI), (V) or (VI) using at least one extraction solvent and e) distilling the product from the extracted organic residue, wherein the extraction solvent is ethyl acetate or cyclopentyl methyl ether (CPME).

21. Method according to claim 17, wherein the compound is selected from the group consisting of ##STR00412## ##STR00413## ##STR00414## ##STR00415## ##STR00416## ##STR00417## ##STR00418## ##STR00419## ##STR00420## ##STR00421## ##STR00422## ##STR00423## ##STR00424##

22. Method according to claim 17, wherein the compound is Diformylxylose (DFX) ##STR00425##

23. Compound of the general formula (I), (III) or (VI) ##STR00426## wherein R.sub.1 and R.sub.1, R.sub.21 and R.sub.21, R.sub.31 and R.sub.31 are the same and are a linear or branched C.sub.1 to C.sub.18 alkyl, a linear or branched C.sub.2 to C.sub.18 alkenyl, a linear or branched C.sub.1 to C.sub.10 alkoxy, a linear or branched C.sub.1 to C.sub.9 alkoxycarbonyl, aminocarbonyl, hydroxycarbonyl, a linear or branched C.sub.1 to C.sub.9 alkoxyalkyl, an unsubstituted cycloalkyl, a linear or branched C.sub.1 to C.sub.6 alkyl substituted cycloalkyl, preferably an unsubstituted cyclohexyl, an unsubstituted C.sub.6 to C.sub.12 aryl, a linear or branched C.sub.1 to C.sub.4 alkyl substituted C.sub.6 to C.sub.12 aryl, or C.sub.7 to C.sub.12 aralkyl, R.sub.2 and R.sub.2, R.sub.22 and R.sub.22, R.sub.32 and R.sub.32 are the same and are hydrogen, a linear or branched C.sub.1 to C.sub.18 alkyl, a linear or branched C.sub.1 to C.sub.9 alkoxyalkyl, or R.sub.2 and R.sub.2 form together with R.sub.1 and R.sub.1 respectively, R.sub.22 and R.sub.22 form together with R.sub.21 and R.sub.21 respectively, R.sub.32 and R.sub.32 form together with R.sub.1 and R.sub.1 respectively, a 5 or 6 membered unsaturated or saturated carbocyclic ring optionally comprising 1 or 2 oxygen atoms, X is selected from the group consisting of hydrogen, fluoro, chloro, bromo, iodo, alkoxycarbonyl, aminocarbonyl, hydroxycarbonyl, a linear or branched C.sub.1 to C.sub.18 alkyl, a C.sub.1 to C.sub.18 alkenyl, a linear or branched C.sub.2 to C.sub.10 alkenyl, a sulfonate and OR.sub.50, wherein R.sub.50 is selected from the group consisting of hydrogen, a linear or branched C.sub.1 to C.sub.18 alkyl, and a linear or branched C.sub.1 to C.sub.9 alkylcarbonyl, and Y is selected from the group consisting of hydrogen, fluoro, chloro, bromo, iodo, a linear or branched C.sub.1 to C.sub.18 alkyl, a C.sub.1 to C.sub.18 alkenyl, a linear or branched C.sub.2 to C.sub.10 alkenyl, a sulfonate and OR.sub.50, wherein R.sub.50 is hydrogen, a linear or branched C.sub.1 to C.sub.18 alkyl and a linear or branched C.sub.1 to C.sub.9 alkylcarbonyl, R.sub.60 is selected from the group consisting of hydrogen, hydroxy and C.sub.1 to C.sub.18 alkoxy, and R.sub.61 is selected from the group consisting of hydrogen, hydroxy, C.sub.1 to C.sub.10 alkylsulfonyl-C.sub.1 to C.sub.5, alkylsulfonylalkenyl and C.sub.1 to C.sub.18 alkyl with the proviso that compounds (1), (10), (11), (12) and (14) ##STR00427## are excluded.

Description

FIGURES

[0143] FIGS. 1A to 1D show the optimization of reaction conditions for direct synthesis of diformylxylose from D-xylose;

[0144] FIG. 2 shows a model alkylation (Menshutkin) reaction with the relationship between solvent polarity and the natural logarithm of the rate of reaction;

[0145] FIG. 3 shows rate constants for Menshutkin reaction in DFX, DPX, and DMGX at 90? C.;

[0146] FIG. 4A shows the conversion of cinnamaldehyde after hydrogenation in DFX and conventional solvents;

[0147] FIG. 4B shows conversion of cinnamaldehyde in DFX as a function of time at different Pd/C catalyst loadings;

[0148] FIG. 5 shows a model Heck reaction with the relationship between solvent polarity and the natural logarithm of the rate of reaction;

[0149] FIG. 6 shows rate constants for Heck reaction in DFX, DPX, DMGX;

[0150] FIG. 7A to 7D shows the results of Ames test on DFX;

[0151] FIG. 8 shows hydrogenolysis yields of aromatic monomers for the extracted formaldehyde-stabilized lignins;

[0152] FIG. 9a shows the stability of pure diformylxylose under acidic conditions;

[0153] FIG. 9b shows the degradation pathway of DFX and its reversible trapping with formaldehyde;

[0154] FIG. 10a shows absorbance spectra of 4-nitroaniline dye in solvents 3, 4 and 24 of claim 13 as well as in DMSO;

[0155] FIG. 10b shows absorbance spectra of N,N-diethyl-4-nitroaniline dye in solvents 3, 4 and 24 of claim 13 as well as in DMSO;

[0156] FIG. 10c shows absorbance spectra of Nile Red dye in solvents 3, 4, 42 and DMSO;

[0157] FIG. 11 shows the plots of 1/concentration of 1-bromodecane as a function of time in cyclopentyl methyl ether (CPME);

[0158] FIG. 12 shows the plots of 1/concentration of 1-bromodecane as a function of time in DES composed of DFX and propyl guaiacol (DFX:PG);

[0159] FIG. 13 shows the plots of 1/concentration of 1-bromodecane as a function of time in DES composed of DFX and Phenol (DFX:PhOH);

[0160] FIG. 14 shows a model alkylation (Menshutkin) reaction with the relationship between solvent polarity and the natural logarithm of the rate of reaction in DPX, DBX, DIBX and in conventional solvents;

[0161] FIG. 15A shows mass spectra depicting fragmentation of molecule and molecular ion for Dipropylxylose;

[0162] FIG. 15B shows mass spectra depicting fragmentation of molecule and molecular ion for Dibutylxylose;

[0163] FIG. 15C shows mass spectra depicting fragmentation of molecule and molecular ion for Diisobutylxylose;

[0164] FIG. 15D shows mass spectra depicting fragmentation of molecule and molecular ion for Dineopentylxylose;

[0165] FIG. 16A shows proton nuclear magnetic resonance (.sup.1H-NMR) spectra of synthesized Diformylxylose in CDCl.sub.3.

[0166] FIG. 16B shows carbon-13 nuclear magnetic resonance (.sup.13C-NMR) spectra of synthesized Diformylxylose in CDCl.sub.3.

[0167] FIG. 17. shows solvent map based on Kamlet-Abboud-Taft parameters ? and ?* comparing DEX, DPX, DBX, DIBX to other solvents.

EXAMPLES

Example 1: Preparation of Diformyl Xylose (DFX)

[0168] D-xylose (15 g, 0.1 mol, 1.0 equiv.) and paraformaldehyde (7.5 g, equivalent to 0.25 mol formaldehyde, 2.5 equiv.) were added to 2-Me-THF (75 mL) in a round bottom flask. Then, H2SO4 (98 wt %, 2.46 mL, 0.045 mol, 0.45 equiv.) was added drop-wise with stirring to avoid the localized concentration of acid, which can degrade the sugar. The mixture was then heated to 80? C. for 3 h with stirring. The resulting solution was cooled to room temperature (?23-25? C.), neutralized with sodium hydroxide saturated aqueous solution, filtered, and concentrated in vacuo using a rotary evaporator with a bath temperature of 45? C. The residue was crystallized directly and washed with ethanol while filtering to remove impurities and by-products. The resulting DFX product is white crystalline solid (298% pure by 1H-NMR and GC-FID).

[0169] Alternatively, if the residue is not crystallizing from the final oil, the following workup can be done. Extract the residue three times with 100 ml of ethyl acetate (or 50 ml of cyclopentyl methyl ether) and 25 ml of water in a separatory funnel. The resulting solution can be distilled at 80? C., under reduced pressure (0.02 mbar) to obtain a light yellow solid. The solid can then be recrystallized in ethanol and dried in a vacuum desiccator, yielding the DFX as a white crystalline solid (298% pure by 1H-NMR and GC-FID).

[0170] FIGS. 1A to 1D show the optimization of reaction conditions for direct synthesis of diformylxylose in 1,4-dioxane (A, C, D) or 2-Me-THF (B) at 80? C. using the conventional procedure (A, C) and the synthesis according to example 1 (B, D).

[0171] NMR spectra for the synthesized DFX are depicted in FIG. 16 A (proton NMR) and FIG. 16 B (carbon NMR).

[0172] The new synthesis to of DFX allows to use the green solvent 2-MeTHE instead of 1,4-dioxane. Moreover, significantly less amount of solvent can now be used (3-times less by volume) to achieve the same yield (75-80%). The new method enables much easier and less time- and labour-consuming workup at the end of the synthesis by excluding distillation and extraction steps. In alternative procedure, ethyl acetate or CPME can be used as extraction solvents instead of n-hexane (a known neurotoxin). Optimization studies reveal that the overall yield of DFX around 75-80% can be achieved after 50 min of the reaction. Also, the yield of furfural is almost negligible in the synthesis according to the present invention, meaning much less degradation of xylose occurred during the reaction.

Example 2a: Preparation of Compounds of Formula (I), (III) and (IV)

[0173] D-xylose (35 g, 1.0 equiv.) and corresponding aldehyde, ketone, or diketoester (3.0 equiv.) were added to 1,4-dioxane (550 mL) in a 1 L round bottom flask. Then, HCl (37 wt %, 1.3 equiv.) was added. The mixture was then heated to 60? C. for 60 min with stirring. The resulting solution was cooled to room temperature (?23-25? C.), neutralized with potassium bicarbonate, filtered, and concentrated in vacuo using a rotary evaporator with a bath temperature of 45? C. The residue was extracted three times with 100 ml of ethyl acetate (or 50 ml of cyclopentyl methyl ether) and 100 ml of water in a separatory funnel. The resulting solution was distilled at 80-95? C., under reduced pressure (0.02 mbar) to obtain a light yellow solid. The yield in all cases was >75%. The solid was then recrystallized in ethanol and dried in a vacuum desiccator, yielding the product as a white crystalline solid (298% pure by 1H-NMR and GC-FID).

[0174] Corresponding aldehydes are for example: benzaldehyde; cyclohexanal; acetaldehyde; propionaldehyde; butyraldehyde; valeraldehyde, isobutyraldehyde, pivaldehyde, 2-methoxyethanal, 2-ethoxyethanal, 2-propoxyethanal, 2-butoxyethanal, 2-pentoxyethanal, 2-hexoxyethanal, 2-heptoxyethanal, 2-phenoxyethanal and 2-benzyloxyethanal.

[0175] Corresponding ketones are for example: acetone, benzophenone, acetophenone, methyl ethyl ketone, methyl isobutyl ketone, methyl-sec-butylketone, cyclopentanone and cyclohexanone.

[0176] Corresponding diketoesters are ?-diketoesters such as methyl pyruvate or ethylpyruvate or ?-diketoesters such as ethyl acetoacetate or methyl acetoacetate.

[0177] GC-MS spectra showing fragmentation of molecules and molecular ion of some of the synthesized compounds are depicted in FIGS. 15A, 15B, 15C and 15D. Specifically, in FIG. 15A for Dipropylxylose (DPX, compound I wherein each of R1 and R1 is ethyl and each of R2 and R2 is hydrogen), in FIG. 15B for Dibutylxylose (DBX, compound I wherein each of R1 and R1 is propyl and each of R2 and R2 is hydrogen), in FIG. 15C for Diisobutylxylose (DIBX, compound I wherein each of R1 and R1 is isopropyl and each of R2 and R2 is hydrogen) and in FIG. 15D for Dineopentylxylose (DNPX, compound I wherein each of R.sub.1 and R.sub.1 is tert-butyl and each of R.sub.2 and R.sub.2 is hydrogen).

Example 2b: Preparation of Compounds of Formula II

[0178] 1,2-O-methylene-?-D-xylofuranose (35 g, 1.0 equiv.) and corresponding carbonate (3.0 equiv.) were added to DMF (550 mL) in a 1 L round bottom flask. Then, NaOH (12 g, 1.3 equiv.) and catalyst TBD (1 mol %) was added. The mixture was then stirred for 4 h at 60? C. The resulting solution was quenched with acetic acid, filtered, and concentrated in vacuo using a rotary evaporator with a bath temperature of 45? C. The obtained mixture was directly purified by flash column chromatography on silica gel (hexane/ethyl acetate 1:6) to produce the productO3,O5-carbonyl-O1,O2-methylene-?-D-xylofuranose.

[0179] The product (1 mol eq.) was then oxidized with KMnO4 (3 mol eq.) in the presence of phosphoric acid (2 mol eq.) and water. The reaction mixture was heated to 70? C. for 15 min to ensure solubilization of all components and then cooled down to 0? C. and stirred for 3 h. The mixtures was extracted 3 times with ethyl acetate and the organic phase was concentrated under vacuum to obtain the product in oil which then can be separated by flash chromatography or distilled.

[0180] Alternatively, D-xylose (35 g, 1.0 equiv.) and corresponding carbonate (3.0 equiv.) were added to DMF (550 mL) in a 1 L round bottom flask. Then, NaOH (12 g, 1.3 equiv.) and catalyst TBD (1 mol %) was added. The mixture was then stirred for 4 h at room temperature. The resulting solution was quenched with acetic acid, filtered, and concentrated in vacuo using a rotary evaporator with a bath temperature of 45? C. The obtained mixture was directly purified by flash column chromatography on silica gel (hexane/ethyl acetate 1:6)

[0181] Corresponding carbonates are for example 1, 3-dioxolan-2-on, diphenyl carbonate, dimethyl carbonate. Additionally, the following catalysts can be used: TBD, DMAP, Zn(OAc).sub.2, NaOCH.sub.3, CS.sub.2CO.sub.3, K.sub.2CO.sub.3.

Example 2c: Preparation of Diformylglucose Isomers

[0182] For preparation of compounds of formula (III) and (IV), in particular of diformylglucose isomers, specifically compounds 25 and 53, pure glucose (35 g) was reacted with 73 ml of 37 wt % HCl and 173 ml of 37 wt % FA in 1550 ml of 1,4-dioxane at 80? C. for 30 min. Before separation, the solution was neutralized with sodium bicarbonate and dried under reduced pressure with a rotary evaporator at 60? C. The residue was extracted five times with 500 ml of ethyl acetate. All organic phases were combined and dried under reduced pressure with a rotary evaporator set a 40? C. The resultant residue was distilled at 125? C. and ?0.06 mbar to obtain a yellowish paste. To obtain pure diformylglucose isomers, the solution was separated by HPLC and targeted peaks were collected using an automated fraction collector.

Example 3: Alkylation (Menshutkin) Reaction

[0183] The reaction was performed between 1,2-dimethylimidazole (0.320 g, 3.33 mmol) and 1-bromodecane (0.65 ml, 3.13 mmol) in the chosen solvent (3 ml) with stirring at 70? C. The rate of the reaction was studied in DFX and 9 other solvents in order to cover a range of polarities and obtain strong correlations (FIG. 2).

[0184] As shown in FIG. 3 the rate of this reaction appears to be proportional to the polarity of the solvent. This observation is consistent with the proposed mechanism of the Menshutkin reaction, where highly polar solvents significantly facilitate a charge separation at the transition state via favorable solute-solvent interactions, accelerating the whole process. This makes solvents like DMSO the best medium for heteroatom alkylations. However, typical highly polar solvents such as DMSO, DMF, NMP are toxic and associated with many environmental and sustainability concerns. In this regard, DFX could be one of the best alternatives for this type of reaction, outperforming some other polar aprotic solvents, including relatively new green ones such as -valerolactone (GVL) or cyclopentyl methyl ether (CPME).

[0185] The same reaction was tested in other compoundsDipropylxylose (DPX, compound I wherein each of R.sub.1 and R.sub.1 is ethyl and each of R.sub.2 and R.sub.2 is hydrogen), Dibutylxylose (DBX, compound I wherein each of R.sub.1 and R.sub.1 is propyl and each of R.sub.2 and R.sub.2 is hydrogen), Diisobutylxylose (DIBX, compound I wherein each of R.sub.1 and R.sub.1 is isopropyl and each of R.sub.2 and R.sub.2 is hydrogen), Dimethylglyoxylate xylose (DMGX, VII).

[0186] As depicted in FIG. 14 DPX, DBX, and DIBX solvents clearly outperformed traditional medium-polarity solvents (1,4-dioxane, 2-Me-THF, EtOAc), second only to much more polar solvents (FIG. 14).

[0187] For DMGX compounds, the procedure was the same as about but at 90? C. instead of 70? C. because melting point of DMGX derivative is about 82? C. For the comparison, the same protocol has been performed on DFX and DPX as well. The observed product was studied in all solvents and corresponding rate constants were calculated (FIG. 3). Since the reaction is very sensitive to solvent polarity, the slowest rate was found in DPX due to its lower polarity term in both Hansen and Kamlet-Taft models. DMGX was lower that DFX as expected as well.

Example 4: Hydrogenation Reaction

[0188] The hydrogenation of cinnamaldehyde (CAL) was examined in a series of organic solvents at 70? C. over Pd/C catalyst in a 25 mL stainless steel Parr reactor. The reactor was loaded with cinnamaldehyde (CAL, 0.665 g, 5 mmol, 1.00 equiv.), Pd/C (1 wt %, 30 mg), and solvent (10 mL) and then sealed and pressurized with H.sub.2 (40 bar). The reactor was heated up to 70? C. with stirring (600 rpm) and held at that temperature for the specified reaction time.

[0189] FIG. 4 (A) shows the conversion of cinnamaldehyde after hydrogenation in various solvents over 1 wt % Pd/C catalyst at 70? C., 30 min (if other not indicated) and FIG. 4(B) shows the conversion of DFX as a function of time at different Pd/C catalyst loadings. 81% and 90% conversion of CAL was achieved in isopropanol (IPA) and methanol (MeOH), respectively. Similarly, high conversions were also achieved in nonpolar aprotic solvents (Dibutyl and Diethyl ethers (DEE), and cyclohexane). Ethers with medium polarity (1,4-dioxane and THF) also facilitated the reaction, while conventional polar aprotic solvents (DMSO, DMF) and DFX were providing the slowest kinetics. Nevertheless, increasing catalyst loading to 10 wt % and letting the reaction proceed for 24 h gives 90% conversion in DFX making it a suitable solvent for this reaction if a cheap non-volatile bio-based solvent is required. In terms of selectivity, hydrocinnamaldehyde was the main product obtained in all tested solvents including DFX with a selectivity of 70% or higher. Hydrogenation in IPA and MeOH led to the formation of acetals, which is an undesirable feature of alcoholic solvents and limits their use for this reaction despite their promising conversions.

[0190] It is important to note that, DFX was stable under hydrogenation conditions (40 bar of H.sub.2, 70? C., 24 h), thus it can be used in reactions requiring high pressure of H.sub.2, elevated temperature, and/or long reaction time, which is a very desirable property for biomass-derived solvents.

Example 5: Cross-Coupling (Heck) Reaction

[0191] Iodobenzene (0.69 mL, 6.00 mmol, 1.00 equiv.), methyl acrylate (0.54 mL, 6.00 mmol, 1.00 equiv.), triethylamine (0.84 mL, 6.00 mmol, 1.00 equiv.), and Pd(OAc)2 (0.1 mol %) were reacted at 90? C. in 5 ml of DFX and other solvents to compare their relative performance.

[0192] The kinetics of Mizoroki-Heck reaction demonstrated strong dependence on the polarity of the solvent used (FIG. 5). DFX provided relatively slow kinetics compared to the solvents of similar polarity. This fact can be related to the absence of any n bond in the structure of DFX, which usually coordinates over the forming palladium-carbon bond. Unsurprisingly, DMF as a solvent with the well-known coordination behavior provided the fastest kinetics, even though its polarity in terms of Kamlet-Abboud-Taft's ?* values was not the highest among tested solvents.

[0193] For DPX and DMGX in model Heck reaction, the following trend was observed: with increasing polarity, the rate of the reaction increases, and all molecules possessed the right properties to promote the reaction (FIG. 6).

[0194] A test of the same reaction protocol in DBX, DIBX (variations of compound (I)) showed accumulation of product with 15% conversion after 10 min of the reaction. For comparison, in 1,4-dioxane at the same reaction time no conversion has been observed.

Example 6a: Physical and Solvation Properties of Diformylxylose

[0195] The most relevant solvent properties were measured for DFX and listed in Table 1a in comparison with other solvents. The boiling point of DFX was measured to be 237? C., which is close to the value of ethylene carbonate. Therefore, DFX can be separated from the reaction mixture by distillation, making its recycling more energy-consuming than for low-boiling solvents. However, high-boiling solvents are considered greener because human exposure risks and environmental impact (specifically aquatic toxicity) are reduced due to low volatility. DFX has a high melting point as well (48? C.). The density of DFX as determined experimentally is 1.35 g/mL at 50? C., which is close to the density of Sulfolane, Cyrene, and some chlorinated solvents. DFX has poor solubility in water, very similar to 2-Me-THE, which allows to easily recover DFX from water and use it in certain applications that require water-immiscible solvent and in water-organic extractions.

[0196] Flash point of 1 (DFX) was measured to be 137.5? C. In terms of safety, the greatest risk of injury is coming from solvents with a lower flash point, e.g. 2-Me-THF (?10? C.), CPME (?1? C.), NMP (86? C.), MTBE (?28? C.), Cyrene (108? C.), GVL (96.1? C.). In this regard, DFX is much more advantageous alternative.

TABLE-US-00020 TABLE 1a Physical and Solvation properties of DFX and other selected solvents. Physical Properties Solubility Density, in water, Hansen Solubility Parameters, Boiling Melting g/ml g/100 g Kamlet-Taft Parameters MPa? Solvents Point, ? C. Poing, ? C. (at 25? C.) (at 25? C.) ? ? ?* ?D ?P ?H Diformylxylose 237 48 1.35 13 0.00 0.82 0.92 17.9 9.0 7.60 DMSO 189 19 0.89 ? 0.00 0.74 1.00 18.4 16.4 10.2 Ethylene carbonate 238 35 1.32 26 0.00 0.32 0.99 18.0 21.7 5.10 Sulfolane 282 27.5 1.26 ? 0.00 0.39 0.98 17.8 17.4 8.70 Cyrene 155 <?20 1.25 ? 0.00 0.61 0.93 18.9 12.7 7.10 NMP 202 ?24 1.25 ? 0.00 0.75 0.90 18.0 12.3 7.20 GVL 207 ?31 1.05 ? 0.00 0.60 0.83 15.5 4.70 6.60 N-butylpyrrolidinone 241 <?75 0.96 ? 0.00 0.92 0.77 17.4 6.70 5.20 1,4-dioxane 101 11.8 1.03 ? 0.00 0.37 0.55 17.3 4.30 8.40 2-MeTHF 80 ?136 0.85 14 0.00 0.58 0.53 16.9 5.00 4.30

[0197] The solvatochromism of DFX (Table 1a) demonstrates that DEX is very polar since its value of measured Kamlet-Abboud-Taft solvatochromic parameter ?* (0.92) is in a range of conventional highly polar aprotic solvents (e.g. DMSO, NMP). Hydrogen bond accepting ability (B) is also very high for DFX, which is due to the presence of 5 oxygen atoms in the structure, which can donate an electron pair. The parameter a was assigned to 0.00 as well as for other PAS because they cannot be hydrogen bond donors. Determination of the Kamlet-Abboud-Taft parameters was based on the absorption spectrum of two dyes (N,N-diethyl-4-nitroaniline and 4-nitroaniline) in different solvents, that allow calculating corresponding values using known procedures (P. G. Jessop, D. A. Jessop, D. Fu and L. Phan, Green Chem., 2012, 14, 1245-1259).

Example 6b: Physical and Solvation Properties of DFX and Other Selected Compounds from Claim 13

[0198] Table 1b depicts Physical and Solvation properties of selected compounds from claim 13.

TABLE-US-00021 Melting Boiling Solubility Compound point, ? C. point, ? C. in water Density 1 48 237 (at 760.00 mmHg) 13 1.35 85 (at 0.015 mmHg) 2 60 n/m n/m n/m 3 34 238 1.75 1.17 4 31 235 <0.1 1.11 5 120 n/m ~0 n/m 11 43 121 n/m n/m 14 83 n/m <0.1 n/m 24 24.5 234 <0.1 1.15 n/mnot measured

[0199] Depending on the protection agent used to synthesize the compounds from claim 13, molecules with diverse physical properties that can be suitable for different applications can be produced. For example, compound 24 has the lowest melting point (24.5? C.) and can be used in reactions not requiring or avoiding high temperatures. Compounds 1, 3, 4, and 11 have a medium-range melting point, while 2, 5, and 14 are considered as high-melting compounds.

[0200] As for boiling points, the experimental values so far indicate little dependency on the type of aldehyde, resulting in boiling points remaining similar and high (234-238? C.). Although, ketone-protected compound 11 has the boiling point significantly lower (120? C.), which opens extra separation opportunities for this molecule. The advantage of having a low volatile solvent is a much lower risk of human exposure and reduced environmental impact, making the solvent more green compared to low-boiling analogs. The boiling points of the molecules are similar to some other green polar aprotic solvents such as Cygnet, N-butylpyrrolidinone, Ethylene carbonate, GVL, N-formylmorpholine. DMF.

[0201] The molecules are very close to being insoluble in water. This low solubility allows for these compounds to be easily separated from water mixtures and opens some applications for them when water-immiscible solvents are required.

[0202] The densities measured for the compounds are comparable to other solvents such as DMSO (1.1 g/cm3) and DCM (1.3 g/cm3).

[0203] Table 1c depicts Kamlet-Taft parameters measured for selected compounds from claim 13.

TABLE-US-00022 Kamlet-Abboud-Taft Compound ? ? ? 1 0 0.82 0.92 3 0 0.63 0.68 4 0 0.51 0.63 24 0 0.56 0.65 THF 0 0.55 0.58 1,4-Dioxane 0 0.37 0.55 2-MeTHF 0 0.58 0.53 Cyclohexane 0 0 0

[0204] According to measured Kamlet-Taft parameters, compounds 3, 4, and 24 are very close by solvation properties to medium-polarity solvents such as THE, 1,4-dioxane, 2-Me-THF. This means that the compounds can successfully complement the list of conventional ethers bringing new properties and, possibly, a safer profile. Moreover, the possibility of these compounds being produced sustainably from renewable sources makes them successful replacement candidates. Compound 1 is significantly more polar and can be a promising renewable alternative to toxic common polar aprotic solvents such as DMF, NMP, sulfolane, etc.

[0205] Based on the measured Kamlet-Abboud-Taft parameters, we established a two-dimensional solvent map to compare some of these compounds with other existing solvents in a parametric space (FIG. 17). Solvents, which are close to one another on the solvent map, are likely to have similar solvent properties. DEX occupies a unique space above conventional polar aprotic solvents, due to its high basicity. DPX, DBX, DIBX occupy region of less polar solvents. However, these areas of the solvent map are not yet populated by any known bio-based solvents or green solvents, which suggests that these compounds are novel solvents and promising candidates for the replacement of some of the highly toxic polar aprotic solvents such as NMP, DMF, DMAc, as well as medium-polarity ethers. The compounds can also have unique applications due to their high hydrogen bond accepting ability. Other compounds from claim 13, due to structural similarity, are likely to populate the same regions while having unique features (e.g. physical properties such as melting point, viscosity, vapour pressure, etc.) that can be wisely selected for specific application.

[0206] The absorbance spectra of 4-nitroaniline dye (cf. FIG. 10a), N,N-diethyl-4-nitroaniline dye (cf. FIG. 10b) as well as of Nile Red dye (cf. FIG. 10c) in the compounds 1, 3, 4 and 24 of claim 13 as well as in DMSO were measured. Nile Red absorbance is dependent on polarity and acidity, but as acidity is 0 in the case of aprotic solvents, the value is only polarity dependent. This differs from ?*, which is both polarity and polarizability dependent. The maximum absorbance of Nile Red in 1, 3, 4 and 24 was measured to be 543, 536, 534.5 and 535 nm respectively. The value for 1 lies in the range between sulfolane (545 nm) and DMF (541 nm), which are two well-known aprotic solvents with high polarity. Values for 3, 4 and 24 are similar to conventional medium polarity aprotic solvents such as dichloromethane (535.2 nm) and acetonitrile (531.6 nm).

[0207] For the compounds 1 (Diformylxylose) and 24, miscibility with different organic solvents was tested to explore how this compound can be separated.

[0208] Table 1d shows Miscibility for Diformylxylose (compound 1) and compound 24 with * indicatingnot miscible:

TABLE-US-00023 Solvents DFX 24 Acetonitrile Anisole Acetone Acetonitrile Chloroform CPME Cyclohexane * DMF DMSO Dioxane di-n-butyl ether * Ethanol Ethyl Acetate Hexane * Isopropanol 2-Me-THF THF Toluene Water *

Example 7: Toxicological Assessment

[0209] The toxicological assessment of DFX was performed using the Ames test to quickly determine if it has a mutagenic and carcinogenic potential.

[0210] An AMES-384 ISO test kit by EBPI Inc. (Canada) with two Salmonella typhimurium bacterial strains (TA100 with base-pair mutation hisG46 and TA98 with frameshift mutation hisD3052) was used. S9 liver homogenate from Aroclor 1254 Sprague-Dawley rats was used in a number of experiments as a source of mammal metabolic enzymes to expand the detection capabilities of the assay. For the test, DFX was dissolved in sterile water (100 mg/mL) and filtered through a 0.22 ?m membrane filter. The maximum concentration of DFX in the exposure well was 80 mg/exposure well. Serial dilution of the sample was performed with a dilution factor of 2 (the minimum tested concentration was 2.5 mg/exposure well). 4-Nitroquinoline-N-oxide (4-NQO) was used as a positive control for the TA100 strain. 2-Nitrofluorene (2-NF) was used as a positive control for the TA98 strain. 2-Aminoanthracene (2-AA) was used as a positive control when a rat liver fraction S9 was added to the TA100 or TA98 strains. For the negative controls, the same quantity of sterile water was added to the wells as was added in the case of the DFX assay. Statistical analysis of the results included calculation of the baseline (the average response of negative control data and standard deviation), positive criteria for considering the testing compound as a mutagen (must be ?2? baseline), and standard error of the mean. All calculations were conducted using an Excel spreadsheet provided by EBPI Inc.

[0211] The following procedure was applied in accordance with manufacturer's guidelines. Briefly, TA100 and TA98 bacterial strains were grown overnight and diluted until OD600 was 0.1 (for TA98) or 0.05 (for TA100). In a 24-well plate, samples containing grown bacteria and negative controls (water), positive controls, sterility controls, 5-serial dilutions of the DFX water (80, 40, 20, 10, 5, 2.5 mg/ml) were prepared and incubated at 37? C. for 100 min in a medium including sufficient histidine to initiate cell division. After the exposure, these samples were diluted in Reversion Media absent histidine in a second 24-well plate, then aliquoted into three 384-well plates and incubated at 37? C. for 48 h. After this, plats were scored visually: yellow wells indicated bacterial growth as they had undergone reverse mutation and could produce the histidine needed for their growth; purple wells indicated no reverse mutation of His+ biopathway in bacteria as they couldn't grow without histidine. The number of yellow wells was calculated and averaged to obtain the mean number of revertants. Baseline and positive criteria were then calculated in accordance with the manufacturer's guide.

[0212] FIG. 7 shows the results of Ames test on DFX using Salmonella TA100 (A, B) and TA98 (C, D) strains in comparison with the positive control (4-Nitroquinoline-N-oxide (4-NQO) for TA100 strain; 2-Nitrofluorene (2-NF) for TA98 strain; 2-Aminoanthracene (2-AA) when S9 mix was added) and negative control (water) with S9 (B, D) and without (A, C). Error bars represent standard error of the mean. Green line is a calculated baseline, incorporating the average of negative control data and standard deviation. Red line is a positive criterion for considering the testing compound as a mutagen (?2? baseline). It is clearly shown that DFX is unable to cause mutations both directly and indirectly, which makes it a promising molecule in terms of health and safety, although other extensive in vitro and in vivo tests are necessary to draw solid conclusions.

Example 8: Biomass Processing

[0213] DFX is able to act as a solvent in formaldehyde-assisted biomass fractionation at several pre-treatment conditions (Table 2). The original procedure employs 1,4-dioxane as the main processing solvent, so it was used as a control. For pre-treatment in DFX, the yields of lignin and cellulose are slightly higher than in dioxane, possibly, due to the presence of solid degradation products (humins), formed because of interaction between acid and sugar derived DFX. The high boiling point of DFX (237? C.) allows to recovering pure DFX at the end of the procedure after evaporating other washing/precipitating solvents such as dioxane, methanol, water.

TABLE-US-00024 TABLE 2 Masses and yields of isolated fractions from the fractionation procedure. Solvent Conditions Lignin Yield Cellulose Yield DFX Yield/Recovery 1,4-dioxane 95? C., 3.5 h 0.44 g (22.2%) 0.88 g (44%) 0.61 g (30.3%) 80? C., 5.5 h 0.47 g (23.7%) 0.94 g (47%) 0.63 g (31.2%) 70? C., 15 h 0.53 g (26.4%) 0.91 g (45.7%) 0.62 g (31%) DFX 95? C., 3.5 h 0.74 g (37%) 1.18 g (59%) 9.17 g (59.4%) 80? C., 5.5 h 0.63 g (31.7%) 1.12 g (56%) 10.56 g (69%) 70? C., 15 h 0.64 g (32%) 0.92 g (46%) 12.57 g (83%)

[0214] The quality of the isolated lignin after pretreatment of Birch wood in DFX was assessed by determining the yield of aromatic monomers that could be produced after hydrogenolysis of the isolated lignin. The yield of monomers obtained after direct hydrogenolysis can be considered as an estimate of the theoretical monomer yield for a given biomass source. Lignin monomer identification and quantification were performed using GC-FID and GC-MS.

[0215] For pre-treatment in DFX, yields of aromatic monomers produced after hydrogenolysis of the isolated formaldehyde-stabilized lignin were in a range 70-80% (wt/wt) as compared with the direct hydrogenolysis of the biomass feedstock (2017 birch wood) (FIG. 8). Hydrogenolysis conditions were as following: catalyst Ru/C, 250? C., 40 bar of H.sub.2, 3.5 h. Monomer yields are given based on dry biomass weight. The results indicate that DFX, like dioxane, can be used to efficiently isolate and purify lignin of good quality, which can be further upgraded in high yields. Overall, DFX is a promising green pre-treatment solvent for lignocellulosic biomass.

[0216] Solubility tests confirmed that DFX is a powerful solvent for the solubilization of lignin. The solubility of propionaldehyde-protected lignin in DFX is 0.633 g/g, which is higher than the corresponding value for 1,4-dioxane (0.450 g/g) and 2-Me-THF (0.330 g/g) after stirring the mixture for 1 h at 85? C.

[0217] Cellulose fibers were depolymerized after pretreatment in DFX in the same manner as for 1,4-dioxane and 2-Me-THF used as pretreatment solvents.

Example 9: Stability of DFX

[0218] The stability of the compound (Ia) where R.sub.1a=R.sub.2a=R.sub.1a=R.sub.2a=H (DFX) was tested in acid and basic conditions.

##STR00337##

Acidic Conditions

[0219] The stability of pure DFX under typical acidic conditions (0.8M HCl) was evaluated to determine if this sugar-derived molecule could be used without extensive degradation. The results demonstrated that at a temperature range between 70 to 95? C., more than 80% of DFX could be recovered (FIG. 9a). The 20% of loss was most likely caused by typical sugar degradation to products such as furfural, carboxylic acids, and polymeric insoluble humins. Interestingly, when adding formaldehyde, around 90% of DFX was stable likely due to a shift in equilibrium towards the reprotection of xylose (FIG. 9b). At the same conditions (95? C. or 70? C., 0.8M HCl) another novel commercially available carbohydrate-derived solvent Cyrene had undergone extensive degradation, forming a DFX remained dark solidified slurry after 15 min of reaction. In this regard, DFX is relatively stable under acidic conditions as its stability is superior to several alternatives.

[0220] In particular FIG. 9a shows the stability of pure diformylxylose at 2.75 wt. % (0.8M) HCl, 95 or 70? C. with formaldehyde added (straight line), or in the absence of it (dashed line), whereas FIG. 9b shows the DFX stabilization with formaldehyde.

[0221] Some variations of compound (I), specifically DPX, DBX, DIBX, Dineopentylxylose (DNPX, compound I wherein each of R.sub.1 and R.sub.1 is tert-butyl and each of R.sub.2 and R.sub.2 is hydrogen) also showed sensitivity to strong acids, which is visually observed as orange-colored solution compared to pure yellowish compound without acid.

Basic Conditions

[0222] To assess DFX stability under basic conditions, we tested a series of organic and inorganic bases at 80? C. and 110? C. for maximum 48 h (Table 6). Visual color change compared to a blank solution of pure DFX indicated some reactions were occurring. After 0.5 h, 24 h, 48 h of exposure, the samples were injected in GC-FID and GC-MS and the area of DFX was compared with the one in blank sample using decane as the internal standard. As a result of this experiment, we identified some potential limitations of this emerging solvent. Specifically, inorganic bases such as K2CO3, NaOH, CsCO3 led to the highest extent of degradation (maximum 21% after 48 h). Triethylamine (NEt3) caused less than 5% of degradation, but led to the formation of dark solution as well as K2CO3, NaOH, CsCO3. Probably, impurities existing in DFX (95% pure) also contribute to a color change as they could interact with bases. Pyridine and KOAc as relatively weak bases didn't show any significant effect on stability of DEX.

TABLE-US-00025 TABLE 6 Stability of DFX under basic conditions DFX degradation, Temperature, Reaction (Y/N) % Base ? C. 0.5 h 24 h 48 h 0.5 h 24 h 48 h NEt.sub.3 80 Y Y Y 3 4 5 K.sub.2CO.sub.3 80 Y Y Y 2 3 7 110 Y Y Y 2 5 13 KOAc 80 N N N 0 2 3 110 Y Y Y 1 3 5 Pyridine 80 N N N 0 0 0 110 N Y Y 0 3 6 NaOH 80 Y Y Y 0 9 17 CsCO.sub.3 110 Y Y Y 3 11 21 80 Y Y Y 1 4 8 110 Y Y Y 1 7 11 *Reaction (Y/N) means color change compared to blank solution.

Thermal Conditions

[0223] DEX remained stable up to 210? C., according to TGA and DSC measurements. After 210? C. degradation with evaporation occurs.

[0224] Some variations of compound (I), specifically DPX, DBX, DIBX, Dineopentylxylose (DNPX, compound I wherein each of R.sub.1 and R.sub.1 is tert-butyl and each of R.sub.2 and R.sub.2 is hydrogen) as well as DMGX showed similar behaviour and were stable up to 200? C.

Hydrogenation Conditions

[0225] DFX remained stable under the following hydrogenation conditions: [0226] 1. 40 bar of H.sub.2, 70? C., 24 h [0227] 2. 40 bar of H.sub.2, 250? C., 3 h

Example 10: Preparing Deep Eutectic Solvents with Diformylxylose (DFX)

[0228] Deep eutectic solvents (DESs) are mixtures composed of a hydrogen bond donor and a hydrogen bond acceptor, resulting in a significantly suppressed melting point compared to those of the individual components. They are similar to ionic liquids but have some advantages to due their tunability, biodegradability and low cost.

[0229] DFX has a melting point of 48? C. and contains 5 oxygens in its structure and, therefore, is a strong hydrogen bond acceptor. Several hydrogen bond donors have been tested to check if they will form eutectic with DFX.

[0230] The following compounds mixed with DFX in 1:1 molar ratio were found to be stable liquids at room temperature and some of them are still liquids even at less than ?18? C. (Table 3)

TABLE-US-00026 TABLE 3 Composition of melting points of DESs produced with DFX Melting point Melting point of the of the mixture Compound compound, ? C. with DFX, ? C. Lactic acid 17 4 < mp < 24 Phenol 40.5 mp < ?18 Glyoxylic acid 46.7 4 < mp < 24 monohydrate Resorcin 110 4 < mp < 24 Catechol 105 4 < mp < 24 Propyl guaiacol 16 mp < ?18

[0231] These findings expand possible opportunities for DFX and its derivatives not only as simple solvents but also constituents for deep eutectic solvents. DESs composed of these molecules can be used in many applications. The physical properties of the liquids are dependent upon the hydrogen bond donor and can be easily tailored for specific applications. The two major application areas of DESs are metal processing (including metal electrodeposition, metal electropolishing, metal extraction and the processing of metal oxides) and synthesis media (e.g. alkylation, ionothermal synthesis, gas adsorption, biotransformations using microorganisms and reactions of sugars, cellulose, and starch, purifying and manufacturing biodiesel, etc).

[0232] We performed the alkylation reaction (the same as in the Example 3) in deep eutectic solvents (DES) composed of DFX and propyl guaiacol (DFX:PG) and DES composed of DFX and Phenol (DFX:PhOH) mixed in 1:1 molar ratio. We observed formation and accumulation of the reaction product with time and the reaction rate constant was quite similar to the one in CPME.

[0233] FIGS. 11, 12 and 13 show the plots of 1/concentration of 1-bromodecane as a function of time in different solvents, corresponding to second-order reaction kinetic. The slope represents a rate constant.

[0234] Since DESs contain hydrogen bond donors, they exhibit properties of protic solvents as well. Therefore applications for protic solvents are applicable to this class of solvents.

[0235] In order to explore DES composed of DFX better, the physical and solvation properties of the mixture of DFX and propyl guaiacol (DFX:PG) mixed in 1:1 molar ratio were measured.

[0236] Table 4 shows physical and solvation properties of DFX:PG (1:1 molar ratio).

TABLE-US-00027 Hansen Melting Solubility, point, Boiling Density, Kamlet-Taft MPa? Solvent ? C. point, ? C. g/ml ? ? ?* ?D ?P ?H DFX:PG <?18 >250 1.2 0.59 0.34 18.7 18.7 9.69 9.68 Acetone ?95 56 0.78 0.08 0.48 0.71 15.5 10.4 7 Acetonitrile ?45 82 0.79 0.35 0.37 0.8 15.3 18 6.1

[0237] Based on the results, one can see that DFX:PG is a polar solvent with protic activity. Kamlet-Taft parameters suggest that DFX:PG is similar to acetonitrile, acetone, ethyl lactate. Hansen Parameters show that DFX:PG has some similarity to 1,3-dioxalane, NMP, Cyrene.

[0238] The Nile red value for DEX:PG is 553 nm, indicating similar chemical behavior to Methanol (550 nm) and Ethanolamine (557 nm).

[0239] In terms of thermal stability, no degradation of components was observed up to 250? C. (followed by refluxing and boiling).

[0240] Table 5 shows miscibility of DES-DEX:PG (1:1 molar ratio) with * indicatingnot miscible.

TABLE-US-00028 Solvents DFX:PG Acetone Acetonitrile CPME Cyclohexane * Dichloromethane DMF DMSO Dioxane Di-n-butyl ether * Ethanol Ethyl Acetate Hexane * Isopropanol 2-MeTHF THF Toluene Water *

Example 10: Hansen Solubility Parameters

[0241] Each solvent can be characterized by three Hansen parameters, each generally measured in MPa 0.5. They are used to determine solubility of targets, estimate rate of reactions, etc. [0242] ?DThe energy from dispersion forces between molecules [0243] ?PThe energy from dipolar intermolecular force between molecules [0244] ?HThe energy from hydrogen bonds between molecules.

[0245] All three parameters were calculated for the molecules of Table 7 using HSPiP 5.3.02 Software (Table 7).

TABLE-US-00029 TABLE 7 Hansen Solubility Parameters of claim 13 and their matching solvents from the Hansen Database HSP Closest match Molecule ?D ?P ?H solvent 1 17.9 9.0 7.6 Dimethyl isosorbide 2 16.8 6.5 5.4 Isophorone 3 16.4 6.1 4.5 Methyl isoamyl ketone 4 16.2 4.9 3.2 Ethyl butyl ketone 5 15.5 3.8 2.5 Di-n-butyl ether 6 16.6 7.0 5.4 Mesityl oxide 7 16.3 6.8 4.8 Mesityl oxide 8 16.5 6.6 5.0 Tri-n-butyl phosphate 9 16.0 4.5 3.1 Isopropyl palmitate 10 15.6 3.6 2.5 Di-n-pentyl-ether 11 16.1 5.3 3.8 Ethyl butyl ketone 12 17.7 5.6 4.0 Bromochloromethane 13 18.5 10.8 8.7 Tetramethylene sulfoxide 14 17.3 7.6 8.5 Epichlorohydrin 15 18.2 27.3 8.0 Ethylene carbonate 17 16.1 4.1 3.0 Glycerol trioleate 18 18.4 4.5 4.0 Ethyl phenyl ether 19 16.3 5.9 3.8 Methyl amyl ketone 20 15.7 5.5 3.2 Methyl isoamyl ketone 21 18.0 10.4 16.7 Glycerol formal 22 16.9 7.9 6.4 Dichloromethane 23 17.2 5.4 3.1 Bromochloromethane 24 16.3 5.2 3.8 Ethyl butyl ketone DMSO 18.4 16.4 10.2 DMSO DMF 17.4 13.7 11.3 DMF NMP 18.0 12.3 7.2 NMP MeCN 15.3 18.0 6.1 MeCN THF 16.8 5.7 8.0 THF

[0246] Based on determined HSP, solvents 1-24 were placed in a 3D space, called Hansen space with three coordinates D, P, H (values from Table 4). This allows for the calculation of a distance between new molecules and already known compounds from the database to determine their chemically similar counterparts. Solvents that are the closest match by properties to the compounds 1-24 are likely to have similar applications and performance. However, in the case of 1-24 they could be produced sustainably from a renewable source and they probably could have a safer profile as they are derived from natural carbohydrates (D-xylose).

[0247] Table 8 depicts Hansen Solubility Parameters for variations of compound (III) of claim 1.

TABLE-US-00030 HSP Compound Structure ?D ?P ?H 25 [00338] 18 10 12.1 26 [00339] 17.1 7.6 9.2 27 [00340] 16.6 7.2 7.9 28 [00341] 16.5 6.1 6.2 29 [00342] 15.7 4.9 0.1 30 [00343] 16.3 6.4 7.7 31 [00344] 16.2 5.5 5.8 32 [00345] 17.4 5.5 6.5 33 [00346] 18.4 5.4 6.8 34 [00347] 17.1 8.9 9.7 35 [00348] 17 7.7 6.2 36 [00349] 17.7 8.6 7.2 37 [00350] 16.9 6.3 5.2 38 [00351] 18.1 11.3 6.8 39 [00352] 17.1 8.8 4.9 40 [00353] 17.1 10.5 5.8 41 [00354] 16.9 6.3 7.9 42 [00355] 16.8 5.2 4 43 [00356] 16.9 7.6 3.8 44 [00357] 17.4 8.4 11 45 [00358] 17.5 7.4 8.1 46 [00359] 16.5 5.9 4.4 47 [00360] 18.3 18.8 17.2 48 [00361] 18.5 17.8 14.3 49 [00362] 18.4 21.5 17.3 50 [00363] 17.9 10.5 18.7 51 [00364] 17.9 11.2 18.3 52 [00365] 18.2 10.1 15.8

[0248] Table 9 depicts Hansen Solubility Parameters for variations of compounds (IV) (V) and (VI) of claim 1

TABLE-US-00031 HSP Compound Structure ?D ?P ?H 53 [00366] 17.9 9.9 10.6 54 [00367] 16.6 7.5 8.2 55 [00368] 16.2 7.1 7.1 56 [00369] 16.1 6 5.2 57 [00370] 15.4 4.8 4.8 58 [00371] 16 6.3 6.5 59 [00372] 15.8 5.4 5.3 60 [00373] 17.3 5.4 5.7 61 [00374] 18.1 5.3 6.2 62 [00375] 16.6 8.8 8.4 63 [00376] 16.3 7 5.6 64 [00377] 17.3 7.6 6.3 65 [00378] 16.3 5.6 4.6 66 [00379] 17.9 9.5 6.7 67 [00380] 16.9 7.3 4.9 68 [00381] 16.8 12.3 6.6 69 [00382] 16.5 6.2 6.6 70 [00383] 16.2 4.5 3.5 71 [00384] 16.7 6.2 3.8 72 [00385] 16.9 8.3 9.5 73 [00386] 16.7 6.6 7.5 74 [00387] 15.9 5.3 3.9 75 [00388] 17.7 18.7 15.9 76 [00389] 17.5 16.8 13.6 77 [00390] 18 22.3 18.2 78 [00391] 17.4 10.9 19.8 79 [00392] 17.3 11 16.9 80 [00393] 17.3 9.2 15 81 [00394] 16.8 7.3 7.4 82 [00395] 16.8 7.1 6.0