METHOD FOR PRODUCING WATER-SOLUBLE SUGARS FROM BIOMASS USING LACTONE-CONTAINING SOLVENTS

Abstract

"METHOD FOR PRODUCING WATER-SOLUBLE SUGARS FROM BIOMASS USING LACTONE-CONTAINING SOLVENTS". The present invention relates to a process for producing an aqueous carbohydrate solution containing C6 sugar-containing oligomers, C6 sugar monomers, C5 sugar-containing oligomers, C5 sugar monomers, or any combination thereof. The process includes the steps of reacting biomass or a biomass-derived reagent with a solvent system that includes a lactone and water and an acid catalyst. The reaction yields a product mixture containing water-soluble C6 sugar-containing oligomers, C6 sugar monomers, C5 sugar-containing oligomers, C5 sugar monomers, or any combination thereof. A solute is added to the product mixture to cause the product mixture to partition into an aqueous layer containing the carbohydrates and a substantially immiscible organic layer containing the lactone.

Description

1 / 37 Descriptive Report of the Invention Patent for METHOD FOR PRODUCING WATER-SOLUBLE SUGARS FROM BIOMASS USING LACTONE-CONTAINING SOLVENTS. DECLARATION OF FEDERAL FUNDING

[001] This invention was made with government support under DEFC02-07ER64494 granted by the Department of Energy. The government has certain rights to the invention. BACKGROUND

[002] Successful carbohydrate recovery from lignocellulosic biomass requires breaking intermolecular bonds in glucan and xylan chains while additionally avoiding the resulting glucose-xylose reaction.9 However, in dilute aqueous neutral or acidic solutions (<10% by weight of mineral acid systems), the resulting glucose reacts further to produce furans or other degradation products. Glucose degradation reactions significantly achieve cellulose depolymerization at temperatures below 250 to 350°C depending on the acid content. This leads to the need for reaction systems with short residence times (10 ms to 1 min) at high temperatures (250 to 400°C) in order to obtain high selectivity for high-conversion glucose,9,10 while minimizing degradation of the desired glucose product.These types of reactions with short residence times are particularly impractical when using heterogeneous starting products such as biomass. Higher yields can be obtained at lower temperatures and longer residence times with the use of increased homogeneous catalyst concentrations such as high concentrations of mineral acid and / or ionic liquids5,8. However, in both cases, the homogeneous catalyst is a very significant expense. Thus, catalyst recovery is of importance. Petition 870200112396, dated 04 / 09 / 2020, page 7 / 97 2 / 37 critical to the commercial viability of these processes. Finally, the recovery and recycling of catalysts end up being a significant component of processing costs3,8,11. Cellulase enzymes operating at only 50°C can achieve near-complete cellulose conversion. However, in these processes, cellulose must be made accessible through a thermochemical pretreatment of the raw cellulosic feedstock. Both enzyme and pretreatment costs are significant obstacles towards the successful commercialization of these processes. For example, enzyme costs are consistently shown to account for between US$0.50 and $2.00 per gallon of ethanol ($2,009), a significant portion of the overall production cost. See, for example, Heather L MacLean and Sabrina Spatari 2009 Environ. Res. Lett. 4 014001 and David B Wilson 2009 Curr Opin Biotechnol Volume 20, Issue 3, Pages 295 to 299.

[003] Strategies have been developed to successfully produce glucose and xylose from biomass while avoiding further degradation despite using low catalyst concentration and low temperature. Such a strategy involves flowing a solvent through a heated compact bed of biomass in a reaction system via flow. This approach decouples the residence times of the solid carbohydrate polymer from its soluble counterpart12,13. These systems are typically limited by their ability to produce concentrated product solutions. In fact, using a 1 wt% aqueous solution of H2SO4 as the extraction solvent, glucose yields of only 45 to 55% are achieved when using a 2 to 4 wt% sugar solution as the feedstock12.

[004] In recent work, GVL-water solutions coupled with very dilute acid concentrations (> 0.1 M H2SO4) or cata Petition 870200112396, dated 04 / 09 / 2020, page 8 / 97 3 / 37 solid acid lysers showed the ability to solubilize lignocellulosic biomass and promote the dehydration of glucose into levulinic acid and xylose into furfural14-16. SUMMARY OF THE INVENTION

[005] A process for producing an aqueous carbohydrate solution comprising C6 sugar-containing oligomers, C6 sugar monomers, C5 sugar-containing oligomers, C5 sugar monomers, or any combination thereof is disclosed and claimed in this document.The process comprises reacting biomass or a biomass-derived reagent with a solvent system comprising (i) an organic solvent selected from the group consisting of beta, gamma, and delta-lactones and combinations thereof and (ii) at least about 1% by weight of water; in the presence of an acid catalyst for a time and under conditions to produce a product mixture in which at least a portion of water-insoluble C6 sugar-containing polymers or oligomers or water-insoluble C5 sugar-containing polymers or oligomers, if present in the biomass or biomass-derived reagent, are converted into water-soluble C6 sugar-containing oligomers, C6 sugar monomers, C5 sugar-containing oligomers, C5 sugar monomers, or any combination thereof. Then, a solute is added to the product mixture in an amount sufficient to cause the product mixture to partition into an aqueous layer and a substantially immiscible organic layer.The partitioning of water-soluble products into the aqueous phase where they can then be concentrated, purified and / or further enhanced with or without any intervention treatment steps.

[006] Thus, included within the scope of the claims is a process for producing an aqueous solution comprising glucose oligomers, glucose monomers, xylose oligomers, mo Petition 870200112396, dated 04 / 09 / 2020, page 9 / 97 4 / 37 xylose monomers or any combination thereof. The process comprises, firstly, reacting biomass or a biomass-derived reagent with a solvent system comprising (i) an organic solvent selected from the group consisting of beta, gamma and delta-lactones and combinations thereof and (ii) at least about 1% by weight of water. The solvent system also includes an acid catalyst. The reaction is carried out for a time and under conditions to produce a product mixture in which at least a portion of water-insoluble glucose-containing polymers or oligomers, or water-insoluble xylose-containing polymers or oligomers, if present in the biomass or biomass-derived reagent, are converted into water-soluble glucose oligomers, glucose monomers, xylose oligomers, xylose monomers or any combination thereof.A non-reactive solute is added to the product mixture in a sufficient quantity to cause the product mixture to partition into an aqueous layer and a substantially immiscible organic layer. The product carbohydrates are contained in the aqueous layer. The lactone is present in the organic layer and can be recycled.

[007] Preferably, the organic solvent is miscible with water or can dissolve from 2% by weight to 25% by weight of water. The method can be conducted using gamma valerolactone (GVL) as the organic solvent. As noted below, the organic solvent can be present in a ratio with water (organic solvent:water) selected from the group consisting of about 60:40, about 65:35, about 70:30, about 75:25, about 80:20, about 85:15, about 90:10, about 95:5, about 97:3, about 98:2 and about 99:1.

[008] The acid catalyst used in any embodiment of the method may be homogeneous or heterogeneous. If the acid catalyst Petition 870200112396, dated 04 / 09 / 2020, page 10 / 97 5 / 37 of the method, if the acid catalyst is homogeneous, preferably it is present in a concentration not greater than 100 mM based on the volume of the solvent system. If the acid catalyst is heterogeneous, preferably it is present in a concentration not greater than 1.0% by weight based on the weight of the solvent system. In any embodiment of the method, the acid catalyst may be a mineral acid, a solid acid catalyst selected from the group consisting of solid Bronsted acid catalysts, solid Lewis acid catalysts and combinations thereof, a heteropolyacid, a mesoporous silica or a zeolite.

[009] The solute used to trigger partitioning of the product mixture is preferably a water-soluble inorganic salt (although any non-reactive solute that triggers partitioning may be used). Sodium chloride is the preferred solute. As shown in Figures 2A and 2B, there is a trade-off in the product composition that depends on how much solute is added to the product mixture. For example, when using NaCl as the solute, a relatively lower salt content of about 4 wt% aqueous NaCl results in a very high concentration of sugars in the product mixture, but only about 50% of the sugars in the biomass reagent are recovered. This approach, however, should be preferred if a product with a high sugar concentration is desired.Conversely, adding 12% by weight of aqueous NaCl to the product mixture (closer to saturation) recovers approximately 90% of the sugars present in the initial mixture, but at a lower concentration in the aqueous phase. Either approach is equally preferable for certain enhancement processes because some enhancement processes will work better with a solution that has a high carbohydrate concentration. Other enhancement processes will perform well with a solution that has... Petition 870200112396, dated 04 / 09 / 2020, page 11 / 97 6 / 37 a more diluted sugar concentration, in which more sugars were recovered.

[0010] The first reaction with the solvent system can be carried out at any temperature, but preferably it is carried out in a temperature range selected from the group consisting of from about 100°C to about 300°C, about 140°C to about 240°C and about 150°C to about 200°C.

[0011] In all reactions described herein, the ratio of lactone to water is preferably at least about 60% by weight of lactone (and increasing) to about 40% by weight of lactone (and decreasing) (60:40; lactone:water). Thus, explicitly included in the disclosed process are lactone to water ratios of 60:40, 65:35, 70:30, 75:25, 80:20, 85:15, 90:10, 95:5, 97:3, 98:2, 99:1 and any ratio falling between the two extremes.

[0012] Any beta, gamma, or delta lactone derived from any corresponding C4 to C16 carboxylic acid may be used in the process. Gamma-lactones and delta-lactones are preferred. C5 to C12 gamma-lactones are even more preferred. Gamma-valerolactone is the most preferred.

[0013] The process can be carried out in a continuous or batch manner. The process can be carried out at any temperature and pressure. However, for reasons of economic viability, it is preferable that the reaction be carried out at a temperature of about 100°C to about 300°C, more preferably from about 140°C to about 240°C and even more preferably from about 150°C to about 200°C. The reaction can be conducted at a static temperature, using any suitable temperature rise, non-linear temperature change or combination thereof. Conducting the process at temperatures above and below these preferred ranges is explicitly within the scope of the process, con Petition 870200112396, dated 04 / 09 / 2020, page 12 / 97 7 / 37 form cited in the claims, unless the claims explicitly state temperature limitations.

[0014] The residence time of the solvent in the reactor can vary at the user's choice and be adjusted empirically based on the selection of biomass or biomass-derived reagent. Generally, however, it is preferable for the solvent to have a residence time in the reactor of 1 min to 24 hours. Residence times above, below, and below these extremes are within the scope of the process. Thus, the process explicitly covers residence times selected from the group consisting of 1 min to 24 hours, 1 min to 20 hours, 1 min to 12 hours, 1 min to 6 hours, 1 min to 3 hours, 1 min to 2 hours, 1 min to 1 hour, and 1 min to 30 min.

[0015] The reaction solvent comprises one or more lactones, water, and an acid. The acid may be a homogeneous acid, a heterogeneous acid, a Bronsted-Lowry acid, a Lewis acid, a solid acid, a mineral acid, or any combination thereof. (Note that any given acid may be described by more than one of the preceding identifiers.) If homogeneous, the acid is present at a dilute concentration, preferably not more than about 100 mM. Thus, acid concentrations between about 0.1 mM and about 100 mM are preferred, more preferably between about 1 mM and about 50 mM, and even more preferably between about 1 mM and about 25 mM. On a weight percent basis, based on the weight of the lactone / water solvent, the acid is preferably present in an amount of about 0.001% by weight to about 1.0% by weight, more preferably from about 0.01% by weight to about 0.1% by weight.

[0016] Thus, the following are revealed in this document:

[0017] 1. A process for producing an aqueous carbohydrate solution comprising C6 sugar-containing oligomers, mono Petition 870200112396, dated 04 / 09 / 2020, page 13 / 97 8 / 37 C6 sugar mers, oligomers containing C5 sugar, C5 sugar monomers or any combination thereof, wherein the process comprises:

[0018] (a) reacting biomass or a biomass-derived reagent with a solvent system comprising (i) an organic solvent selected from the group consisting of beta, gamma and delta lactones and combinations thereof and (ii) at least about 1% by weight of water; in the presence of an acid catalyst for a time and under conditions to produce a product mixture in which at least a portion of water-insoluble C6 sugar-containing polymers or oligomers or water-insoluble C5 sugar-containing polymers or oligomers, if present in the biomass or biomass-derived reagent, are converted into water-soluble C6 sugar-containing oligomers, C6 sugar monomers, C5 sugar-containing oligomers, C5 sugar monomers or any combination thereof; and then

[0019] (b) add a solute to the product mixture from step (a) in an amount sufficient to cause the product mixture to partition into an aqueous layer and a substantially immiscible organic layer.

[0020] 2. The method according to claim 1, in which the organic solvent is miscible with water.

[0021] 3. The method according to claim 1, wherein the organic solvent can dissolve from 2% by weight to 40% by weight of water.

[0022] 4. The method, according to any previous claim, in which the organic solvent is gamma valerolactone (GVL).

[0023] 5. The method, according to any previous claim, in which the organic solvent is present in a mass ratio with water, organic solvent:water, selected from the group that Petition 870200112396, dated 04 / 09 / 2020, page 14 / 97 9 / 37 consists of approximately 60:40, approximately 65:35, approximately 70:30, approximately 75:25, approximately 80:20, approximately 85:15, approximately 90:10, approximately 95:5, approximately 97:3, approximately 98:2, and approximately 99:1.

[0024] 6. The method, according to any previous claim, wherein the acid catalyst is homogeneous or heterogeneous and, if the acid catalyst is homogeneous, it is present in a concentration not greater than 100 mM based on the volume of the solvent system and, if the acid catalyst is heterogeneous, it is present in a concentration not greater than 1.0% by weight based on the weight of the solvent system.

[0025] 7. The method according to any one of claims 1 to 6, wherein the acid catalyst is a mineral acid or an organic acid.

[0026] 8. The method according to any one of claims 1 to 6, wherein the acid catalyst is a solid acid catalyst selected from the group consisting of solid Bronsted acid catalysts, solid Lewis acid catalysts and combinations thereof.

[0027] 9. The method according to claim 8, wherein the solid acid catalyst is a heteropolyacid.

[0028] 10. The method according to claim 8, wherein the solid acid catalyst is an amorphous or mesoporous silica, which may be defunctionalized or functionalized with an acid modifier.

[0029] 11. The method according to claim 8, wherein the solid acid catalyst is a zeolite.

[0030] 12. The method, according to any previous claim, in which the solute is an inorganic salt soluble in water.

[0031] 13. The method according to claim 12, wherein salt is added to the product mixture in a saturating amount. Petition 870200112396, dated 04 / 09 / 2020, page 15 / 97 10 / 37 action.

[0032] 14. The method according to claim 12, wherein the salt is sodium chloride.

[0033] 15. The method, according to any previous claim, wherein step (a) is conducted in a temperature range selected from the group consisting of from about 100°C to about 300°C, about 140°C to about 240°C and about 150°C to about 200°C.

[0034] 16. The method, according to any previous claim, in which step (a) is conducted in a dynamic temperature range.

[0035] 17. The method according to claim 16, wherein the dynamic temperature range rises from a first temperature to a second temperature that is higher than the first temperature.

[0036] 18. The method according to claim 16, wherein the dynamic temperature range changes from a first temperature to a second temperature in a non-linear manner, a discontinuous manner or a combination thereof.

[0037] 19. The method according to any preceding claim, wherein in step (a) the biomass or a biomass-derived reagent comprises water-insoluble glucose-containing polymers or water-insoluble xylose-containing polymers or oligomers or any combination thereof and these, if present, are converted into water-soluble glucose-containing oligomers, glucose monomers, water-soluble xylose-containing oligomers, xylose monomers or any combination thereof.

[0038] 20. The method, according to any previous claim, in which in step (a), the residence time of the reaction is selected Petition 870200112396, dated 04 / 09 / 2020, page 16 / 97 11 / 37 swimming from the group consisting of 1 min at 24 hours, 1 min at 20 hours, 1 min at 12 hours, 1 min at 6 hours, 1 min at 3 hours, 1 min at 2 hours, 1 min at 1 hour and 1 min at 30 min. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figures 1A, 1B, 1C, 1D, 1E, and 1F are the fractionation results for various solvents. All experiments were performed with corn straw unless otherwise specified. All solutions contained 5 mM H2SO4. The solid line in Figures 1A, 1B, and 1C represents the increasing temperature inside the reactor during fractionation. The legend is shown in Figure 1D. Figure 1A shows the carbohydrate concentration as a function of solvent volume for 80 wt% GVL to 20 wt% water. Figure 1B shows the carbohydrate concentration as a function of solvent volume for 90 wt% GVL to 10 wt% water. Figure 1C shows the carbohydrate concentration as a function of solvent volume for water. Figure 1D shows the carbohydrate concentration as a function of solvent volume for 80 wt% GVL to 20 wt% ethanol.Figure 1E shows the total soluble carbohydrate yields using various solvent systems. Figure 1F shows the total soluble carbohydrate yield as a time-lapse function of temperature rise.

[0040] Figures 2A, 2B, and 2C show the aqueous phase separation and carbohydrate recovery from GVL / water mixtures using NaCl. The stacked bars represent fractions of the total carbohydrate yield. The solid line represents the total mass concentration of sugars in the solution. Figure 2A shows results for 80 wt% GVL to 20 wt% water. Figure 2B shows results for 90 wt% GVL to 10 wt% water. The salt content is given as a mass fraction. Petition 870200112396, dated 04 / 09 / 2020, page 17 / 97 12 / 37 of the total amount of water present. Figure 2C shows the effect of fraction removal and time shortening on temperature increase. For results marked with *, fractions containing less than 3% of total carbohydrates were removed.

[0041] Figures 3A and 3B show carbohydrate enhancement. Figure 3A shows monomer production from the separated aqueous phase as a residence time function at 413 K. The separated aqueous phase was treated unchanged. Figure 3B shows furan production from soluble carbohydrate as a residence time function at 443 K. The separated aqueous phase, to which 100 mM AlCl3 was added, was treated in the presence of a 2-sec-butylphenol (SBP) organic layer. The reported yields were calculated based on the analysis of both phases. Sugars were measured only in the aqueous phase, and 94 to 100% of furans were recovered in SBP.

[0042] Figure 4 shows the schematic diagram of the through-flow reactor used in the Examples.

[0043] Figures 5A and 5B show the results of the concentration of water-insoluble solids fraction resulting from the extraction of corn straw in GVL / water mixtures. All solutions contain 5 mM H2SO4. Figure 5A shows corn straw extracted with a mixture of 80% by weight GVL to 20% by weight water. Figure 5B shows corn straw extracted with a mixture of 90% by weight GVL to 10% by weight water.

[0044] Figures 6A, 6B, 6C, and 6D show cumulative carbohydrate yields as a function of solvent volume. All solvent contained 5 mM H2SO4. Cumulative xylose yield was calculated from the initial volume to the final volume (0 to 260 ml). Cumulative glucose yield was calculated from the volume Petition 870200112396, dated 04 / 09 / 2020, page 18 / 97 13 / 37 final for the initial volume (260 to 0 ml). The intersection between the cumulative glucose and xylose yield curves represents the fractionation volume at which equal portions of the total recoverable sugars can be recovered in separate solvent fractions. Figure 6A shows the cumulative yield obtained with an 80 wt. GVL solution in 20 wt. water. Figure 6B shows the cumulative yield obtained with a 90 wt. GVL solution in 10 wt. water. Figure 6C shows the cumulative yield obtained with water. Figure 6D shows the cumulative yield obtained with an 80 wt. ethane solution in 20 wt. water.

[0045] Figures 7A and 7B show the aqueous phase separation and carbohydrate recovery from simulated carbohydrate feeds in GVL mixtures using NaCl. The salt content is given as the mass fraction of the total amount of water present. Stacked bars represent fractions of the total carbohydrate yield. The solid line represents the total mass concentration of sugars in the solution. Figure 7A shows the results for 80 wt% GVL to 20 wt% water. Figure 7B shows the results for 90 wt% GVL to 10 wt% water. DETAILED DESCRIPTION ABBREVIATIONS AND DEFINITIONS:

[0046] Biomass as used in this document includes materials containing cellulose, hemicellulose, lignin, protein, and carbohydrates such as starch and sugar. Common forms of biomass include trees, shrubs, and grasses, as well as corn stalks, municipal solid waste, waste paper, and organic waste. Biomass high in starch, sugar, or protein, such as corn, grains, fruits, and vegetables, is usually consumed as food. Conversely, biomass high in cellulose, hemicellulose, and lignin Petition 870200112396, dated 04 / 09 / 2020, page 19 / 97 14 / 37 is not readily digestible by humans and is primarily used for paper and wood products, fuel, or is disposed of as waste. Biomass as used in this document explicitly includes branches, bushes, sugarcane, corn and corn stalks, energy crops, forests, fruits, flowers, grains, grasses, herbaceous crops, leaves, tree bark, needles, firewood, roots, seedlings, short-rotation tree crops, shrubs, yellow millet, trees, vegetables, vines, hardwoods and softwoods. Additionally, biomass includes organic waste materials generated from agricultural processes that include farm and forestry activities, specifically including forest wood waste. Biomass includes virgin biomass and / or non-virgin biomass such as agricultural biomass, commercial organics, construction and demolition waste, municipal solid waste, paper waste, and organic waste.Municipal solid waste generally includes debris, garbage, rubble, refuse, and leftovers that are normally discarded by occupants of residential dwellings and by business, industrial, and commercial establishments, including, but not limited to: paper and cardboard, plastic, crumbs, wood chips, sawdust, and the like.

[0047] Biomass derivative = compounds or compositions manufactured or purified from biomass.

[0048] Bronsted-Lowry Acid / Base = A Bronsted-Lowry acid is defined herein as any chemical species (atom, ion, molecule, compound, complex, etc.), without limitation, that denotes or transfers one or more protons to another chemical species. Monoprotic, diprotic, and triprotic acids are explicitly included in the definition. A Bronsted-Lowry base is defined herein as any chemical species that can accept a proton from another chemical species. Included among the Bronsted acids Petition 870200112396, dated 04 / 09 / 2020, page 20 / 97 15 / 37 Lowry acids include mineral acids, organic acids, heteropolyacids, solid acid catalysts, zeolites, etc., as defined in this document. It should be noted that this list is illustrative, not exhaustive. The shortened term Bronsted is also used synonymously with Bronsted-Lowry.

[0049] Carbohydrate is defined in this document as a compound consisting only of carbon, hydrogen and oxygen atoms, in any ratio.

[0050] C5 carbohydrate refers to any carbohydrate, without limitation, that has five (5) carbon atoms. The definition includes pentose sugars of any description and stereoisomerism (e.g., D / L aldopentoses and D / L ketopentoses). C5 carbohydrates include (by way of example and without limitation) arabinose, lycose, ribose, ribulose, xylose, and xylulose.

[0051] Carbohydrate Ce refers to any carbohydrate, without limitation, that has six (6) carbon atoms. The definition includes hexose sugars of any description and stereoisomerism (e.g., D / L aldohexoses and D / L ketohexoses). Carbohydrates Ce include (by way of example, but without limitation) allose, altrose, fructose, galactose, glucose, gulose, idose, mannose, psicose, sorbose, tagatose, and talose.

[0052] Cellulose refers to a polysaccharide of glucose monomers ((CeHwO5)n); cellulosic biomass refers to biomass as described above comprising cellulose and / or consisting essentially of cellulose and / or consisting entirely of cellulose. Lignocellulosic biomass refers to biomass comprising cellulose, hemicellulose, and lignin. Lignocellulosic biomass comprises xylose as well as hemicellulose. For the experiments described below, dried corn straw was obtained from the Great Lakes Bioenergy Research Center, Madison, Wisconsin, USA. Borwood Petition 870200112396, dated 04 / 09 / 2020, page 21 / 97 16 / 37 of the dried product was obtained from the company Mascoma, Hanover, NH.

[0053] Glucose-containing oligomers, glucose-containing polymers, glucose-containing reagent, C6-containing reagent = any chemical species that has any type of intramolecular linkage comprising a glucose or other C6 sugar unit. The definition explicitly includes disaccharides containing glucose (such as, but not limited to, sucrose, lactose, maltose, trehalose, cellobiose, cojibiose, nigerose, isomaltose, β,β-trehalose, α,β-trehalose, soforose, laminaribiose, gentiobiose, turanose, maltulose, palatinose, gentiobiulose, etc.), trisaccharides (such as, but not limited to, isomaltotriose, nigerotriose, maltotriose, maltotriulose, raffinose, etc.) and larger oligosaccharides and polysaccharides, as well as larger and more complex polymers containing glucose and carbohydrates and other polymers and carbohydrates containing a C6 sugar unit, such as, but not limited to, starch, amylose, amylopectin, glycogen, cellulose, hemicelluloses (e.g., xyloglucan, glucomannan, etc.).), linocellulose and the like. Linear, branched, and macrocyclic oligomers and polymers containing glucose, including those found in biomass, are explicitly included in the definition. Likewise, xylose-containing oligomers, xylose-containing polymers, xylose-containing reagents, C5-containing reagents = any chemical species that has any type of intramolecular linkage comprising a xylose or other C5 sugar unit.

[0054] Heteropolyacid = A class of solid-phase acids exemplified by such as H4SiWi2O4O, H3PW12O4O, H6P2W18O62, H3+xPMOi2-xVxO4O and the like. Heteropolyacids are solid-phase acids that have a well-defined local structure, the most common of which is the tungsten-based Keggin structure. The Keggin unit comprises a central PO4 tetrahedron, surrounded by 12WO6 octahedron. The standard unit has a net charge of (-3) and therefore requires three Petition 870200112396, dated 04 / 09 / 2020, page 22 / 97 17 / 37 cations to satisfy electroneutrality. If the cations are protons, the material functions as a Brønsted acid. The acidity of these compounds (as well as other physical characteristics) can be adjusted by substituting different metals in place of tungsten in the Keggin structure. See, for example, Bardin et al. (1998) Acidity of Keggin-Type Heteropolycompounds Evaluated by Catalytic Probe Reactions, Sorption Microcalorimetry and Density Functional Quantum Chemical Calculations, J of Physical Chemistry B, 102: 10.817 to 10.825.

[0055] Homogeneous catalyst = A catalyst that exists in the same phase (solid, liquid or gas) as the reactants under reaction conditions.

[0056] Heterogeneous catalyst = A catalyst that exists in a different phase from the reactants under reaction conditions.

[0057] Lactone as used herein refers to an unsubstituted or substituted cyclic ester having a single oxygen heteroatom in the ring and having four to six total ring atoms – that is, beta, gamma, and delta-lactones derived from corresponding C4 to C16 carboxylic acids. Thus, as used herein, the term lactone explicitly includes (without limitation) unsubstituted and substituted beta and gamma butyrolactones and beta, gamma, and delta valerolactones to beta, gamma, and delta hexadecalactones. Some lactones are water-miscible, such as GVL; other lactones have more limited water solubility. Those lactones that can dissolve in at least about 1% by weight of water and more preferably in at least about 5% by weight (or more) of water (until miscible) are suitable for use in the process described herein. Gamma-lactones and delta-lactones are preferred. Gamma valerolactone is the most preferred.

[0058] Mineral acid = any acid that contains minerals, including Petition 870200112396, dated 04 / 09 / 2020, page 23 / 97 18 / 37 ve (by way of example and without limitation), hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, boric acid, hydrofluoric acid, hydrobromic acid and the like.

[0059] Organic acid = any organic acid, without limitation, such as toluenesulfonic acid, formic acid, acetic acid, trifluoroacetic acid, oxalic acid and the like.

[0060] Lewis Acid / Base = A Lewis acid is defined in this document as any chemical species that is an electron pair acceptor, that is, any chemical species that has the ability to receive an electron pair, without limitation. A Lewis base is defined in this document as any chemical species that is an electron pair donor, that is, any chemical species that has the ability to donate an electron pair, without limitation.

[0061] A Lewis acid (also called a Lewis acid catalyst) can be any Lewis acid based on transition metals, lanthanide metals, and metals from Groups 4, 5, 13, 14, and 15 of the periodic table of elements, which include boron, aluminum, gallium, indium, titanium, zirconium, tin, vanadium, arsenic, antimony, bismuth, lanthanum, dyspropsium, and ytterbium. One skilled in the art will recognize that some elements are better suited in practice in the method. Illustrative examples include AlCh, (alkyl)AlCl2, (C2Hõ)2AlCl, (C2Hõ)3Al2Cl3, BF3, SnCl4, and T1Cl4.

[0062] Group 4, 5, and 14 Lewis acids are generally designated by the formula MX4; wherein M is a Group 4, 5, or 14 metal and X is a halogen independently selected from the group consisting of fluorine, chlorine, bromine, and iodine, preferably chlorine. X may be a pseudohalogen. Non-limiting examples include titanium tetrachloride, titanium tetrabromo, vanadium tetrachloride, tin tetrachloride, and zirconium tetrachloride. Lewis acids Petition 870200112396, dated 04 / 09 / 2020, page 24 / 97 19 / 37 of Group 4, 5 or 14 may also contain more than one type of halogen. Non-limiting examples include titanium bromide trichloride, titanium dibromide dichloride, vanadium bromide trichloride and tin chloride trifluoride.

[0063] Lewis acids of Group 4, 5 and 14 useful in the method may also have the general formula MRnX4-n; wherein M is a Group 4, 5 or 14 metal; wherein R is a monovalent hydrocarbon radical selected from the group consisting of C1 to C12 alkyl, aryl, arylalkyl, alkylaryl and cycloalkyl radicals; wherein n is an integer from 0 to 4; and wherein X is a halogen independently selected from the group consisting of fluorine, chlorine, bromine and iodine, preferably chlorine. X may be a pseudo-halogen. Non-limiting examples include benzyltitanium trichloride, dibenzyltitanium dichloride, benzylzirconium trichloride, dibenzylzirconium dibromide, methyltitanium trichloride, dimethyltitanium difluoride, dimethylthia dichloride, and phenylvanadium trichloride.

[0064] Lewis acids of Group 4, 5 and 14 useful in the method may also have the general formula M(RO)nR'mX(m+n); where M is a Group 4, 5 or 14 metal; where RO is a monovalent hydrocarbon radical selected from the group consisting of C1 to C30 alkoxy, aryloxy, arylalkoxy, alkyl aryloxy radicals and R' is a monovalent hydrocarbon radical selected from the group consisting of C1 to C12 alkyl, aryl, aryl alkyl, alkyl aryl and cycloalkyl radicals; n is an integer from 0 to 4; m is an integer from 0 to 4 such that the sum of n and n is not greater than 4; and X is a halogen selected independently from the group consisting of fluorine, chlorine, bromine and iodine, preferably chlorine. X may be a pseudohalogen.Non-limiting examples include methoxytitanium trichloride, n-butoxytitanium trichloride, di(isopropoxy)titanium dichloride, phenoxytitanium tribromide, phenylmethoxyzirconium trifluoride, methyl methoxytitanium dichloride, methoxytitanium dichloride. Petition 870200112396, dated 04 / 09 / 2020, page 25 / 97. 20 / 37 til methoxitin and benzyl isopropoxyvanadium dichloride.

[0065] Group 5 Lewis acids may have the general formula MOX3; where M is a Group 5 metal and X is a halogen independently selected from the group consisting of fluorine, chlorine, bromine, and iodine, preferably chlorine. A non-limiting example is vanadium oxychloride.

[0066] Group 13 Lewis acids may have the general formula MX3; wherein M is a Group 13 metal and X is a halogen independently selected from the group consisting of fluorine, chlorine, bromine, and iodine, preferably chlorine. X may be a pseudohalogen. Non-limiting examples include boron trichloride, boron trifluoride, gallium trichloride, indium trifluoride, and the like.

[0067] The Group 13 Lewis acids useful in the method may also be of the general formula: MRnX3-n; wherein M is a Group 13 metal; R is a monovalent hydrocarbon radical selected from the group consisting of C1 to C12 alkyl, aryl, arylalkyl, alkylaryl and cycloalkyl radicals; and “n” is a number from 0 to 3; and X is a halogen independently selected from the group consisting of fluorine, chlorine, bromine and iodine, preferably chlorine. X may be a pseudo-halogen. Non-limiting examples include ethylaluminum dichloride, methylaluminum dichloride, benzylaluminum dichloride, isobutylgallium dichloride, diethylaluminum chloride, dimethylaluminum chloride, ethylaluminum sesquichloride, methylaluminum sesquichloride, trimethylaluminum and triethylaluminum.

[0068] The Group 13 Lewis acids useful in this disclosure may also have the general formula M(RO)nR'mX(m+n); where M is a Group 13 metal; where RO is a monovalent hydrocarbon radical selected from the group consisting of C1 to C30 alkoxy, aryloxy, arylalkoxy, alkyl aryloxy radicals and R' is a monovalent hydrocarbon radical selected from the group consisting of alkyl radicals Petition 870200112396, dated 04 / 09 / 2020, p. 26 / 97 21 / 37 C12 aryl, aryl alkyl, alkyl aryl and cycloalkyl; n is an integer from 0 to 3; m is a number from 0 to 3 such that the sum of n and m is not greater than 3; and X is a halogen independently selected from the group consisting of fluorine, chlorine, bromine and iodine, preferably chlorine. X may be a pseudo-halogen. Non-limiting examples include methoxyaluminum dichloride, ethoxyaluminum dichloride, 2,6-di-tert-butylphenoxyaluminum dichloride, methoxymethylaluminum chloride, 2,6-di-tert-butylphenoxymethylaluminum chloride, isopropoxygallium dichloride and phenoxymethylindium fluoride.

[0069] The Group 13 Lewis acids useful in this disclosure may also have the general formula M(RC(O)O)nR'mX3-(m+n); wherein M is a Group 13 metal; wherein RC(O)O is a monovalent hydrocarbacyl radical selected from the group consisting of C2 to C30 alkacoxy, aryl acyloxy, aryl alkyl acyloxy, alkyl aryl acyloxy radicals; R' is a monovalent hydrocarbon radical selected from the group consisting of C1 to C12 alkyl, aryl, aryl alkyl, alkyl aryl and cycloalkyl radicals; n is an integer from 0 to 3; m is a number from 0 to 3 such that the sum of them is not greater than 3; and X is a halogen independently selected from the group consisting of fluorine, chlorine, bromine and iodine, preferably chlorine. X may be a pseudohalogen. Non-limiting examples include acetoxylaluminum chloride, benzoyloxyaluminum dibromide, benzoyloxygallium difluoride, methyl acetoxylaluminum chloride, and isopropyloxyindium trichloride. The most preferred Lewis acids for use in the method are general metal halides and more specifically transition metal halides, lanthanide metal halides, and Group 5, 13, and 14 metal halides. Among the metal halides, metal chlorides are preferred. Preferred transition metal chlorides include, but are not limited to, TiCl4, VCl3, and the like. Preferred Group 13 and 14 metal halides and chlorides include, but are not limited to, BF3, AlCh, Petition 870200112396, dated 04 / 09 / 2020, page 27 / 97 22 / 37 SnCl4, InCl3, and GaCl3. Preferred lanthanoid chlorides include, but are not limited to, LaCh, DyCh, and YbCl3.

[0070] The terms solid acid and solid acid catalyst are used synonymously in this document and may comprise one or more solid acid materials. The solid acid catalyst may be used independently or may alternatively be used in combination with one or more mineral acid catalysts or other types of catalysts. Exemplary solid acid catalysts that may be used include, but are not limited to, heteropolyacids, acid resin-type catalysts, mesoporous silicas, acid clays, sulfated zirconia, molecular sieve material, zeolites, and acid material on a thermoset support. Where an acid material is provided on a thermoset support, the thermoset support may include, for example, one or more of silica, tin oxide, niobium, zirconia, titania, carbon, alpha alumina, and the like. The oxides themselves (e.g., ZrO2, SnO2, TiO2, etc.)) which can optionally be doped with additional acid groups such as SO42- or SO3H can also be used as solid acid catalysts.

[0071] Additional examples of solid acid catalysts include strongly acidic ion exchangers such as sulfonic acid groups containing crosslinked polystyrene. For example, Amberlyst® brand resins are styrene divinylbenzene copolymers functionalized with different surface properties and porosities. (These types of resins are hereby designed as Amb resins, followed by a numerical identifier of the specific resin subtype where appropriate.) The functional group is generally of the sulfonic acid type. Amberlyst® brand resins are supplied as gel-like or macrocrosslinked spherical capsules. (Amberlyst® is a registered trademark of Dow Chemical Co.). Similarly, resins Petition 870200112396, dated 04 / 09 / 2020, page 28 / 97 23 / 37 of the Nafion® brand are fluoropolymer copolymers based on sulfonated tetrafluoroethylene that are solid acid catalysts. Nafion® is a registered trademark of E.I. du Pont de Nemours & Co.

[0072] Solid catalysts may be in any shape or form now known or developed in the future, such as, but not limited to, granules, powder, beads, pills, pellets, flakes, tablets, spheres, or other shapes.

[0073] Zeolites can also be used as solid acid catalysts. Of these, H-type zeolites are generally preferred, for example, zeolites in the mordenite group or fine-pored zeolites such as X, Y and L zeolites, for example, mordenite, erionite, chabazite or faujasite. Ultrastable zeolites in the faujasite group that have been dealuminated are also suitable.

[0074] The term solute is broadly defined in this document to include any non-reactive salt (such as NaCl, NaBr and any other inorganic or organic salts) or other non-reactive organic or inorganic solutes that trigger the formation of an aqueous layer and a substantially immiscible organic layer containing the lactone when the solute is added to the product mixture after the reaction. Sodium salts are preferred. Sodium chloride is also preferred.

[0075] The numerical ranges as used herein are intended to include every number and subset contained within that range, whether or not specifically disclosed. Furthermore, these numerical ranges are to be interpreted as supporting a claim directed to any number or subset of number within that range. For example, a disclosure of 1 to 10 is to be interpreted as supporting a range of 2 to 8, 3 to 7, 5, 6, 1 to 9, 3.6 to 4.6, 3.5 to 9.9, and so forth. Petition 870200112396, dated 04 / 09 / 2020, p. 29 / 97 24 / 37

[0076] All references to singular features or limitations must include the corresponding plural features or limitations and vice versa, unless otherwise specified or clearly indicated otherwise by the context in which the reference is made.

[0077] The processes described in this document can be performed in batch, semi-continuous and / or continuous mode, all of which are explicitly included herein.

[0078] All combinations of method or process steps as used in this document may be performed in any order, unless otherwise specified or clearly indicated otherwise by the context in which the combination in question is made.

[0079] The methods described and claimed may comprise, consist of, or consist essentially of the essential elements and limitations of the methods disclosed, as well as any optional or additional ingredients, components, or limitations described herein or otherwise useful in synthetic organic chemistry. THE PROCESS:

[0080] The process yields an aqueous carbohydrate solution, selectively and with minimal degradation of carbohydrate monomers. The process comprises reacting biomass or a biomass-derived reagent with a solvent system comprising (i) an organic solvent selected from the group consisting of beta, gamma, and delta-lactones and combinations thereof, and (ii) at least about 1% by weight of water. The solvent system also includes an acid catalyst. The reaction is conducted for a time and under conditions to produce a product mixture in which at least a portion of water-insoluble glucose-containing polymers or oligomers, or water-insoluble xylose-containing polymers or oligomers, are present. Petition 870200112396, dated 04 / 09 / 2020, page 30 / 97 25 / 37 Water, if present in the biomass or biomass-derived reagent, is converted into water-soluble glucose oligomers, glucose monomers, xylose oligomers, xylose monomers, or any combination thereof. A non-reactive solute is added to the product mixture in sufficient quantity to cause the product mixture to partition into an aqueous layer and a substantially immiscible organic layer. The product carbohydrates are contained in the aqueous layer. The lactone is present in the organic layer and can be recycled.

[0081] In Figures 1A and 1B, the results of carbohydrate fraction concentration as a function of the volume of solvent flowed through the reactor shown in Figure 4 are shown for reaction solvents containing mixtures of 80 wt% GVL to 20 wt% water (80 / 20 GVL, Figure 1A) and 90 wt% GVL to 10 wt% water (90 / 10 GVL, Figure 1B), respectively (see Examples for full experimental details). Both solutions contained 5 mM H2SO4 (~0.05 wt%). In both cases, the concentrations of C5 (xylose and xylo-oligomer) and C6 (glucose and gluco-oligomer) fractions reach a maximum between about 160°C and about 200°C and then decrease at higher temperatures. Equivalent results obtained with water as a solvent show significantly different behavior, with glucose concentration continuously increasing with increasing temperature up to 219.85°C (493°K) and potentially higher (see Figure 1C).This result indicates that GVL favors cellulose deconstruction and hydrolysis, with most cellulose hydrolysis occurring below approximately 210 °C. Interestingly, when ethanol is used instead of GVL, a maximum concentration of C6 was also observed (see Figure 1D). However, most C6 concentrations were lower when using 80 / 20 GVL-para. Petition 870200112396, dated 04 / 09 / 2020, page 31 / 97 26 / 37 ethanol, which suggests that ethanol acts more as an inhibitor than as a promoter of cellulose breakdown. Figure 1E is a histogram of the cumulative results using various solvent systems for comparison purposes.

[0082] Unlike water or water-ethanol mixtures, lactone / water mixtures leave almost no solids in the reactor. The various GVL / water fractions contain water-insoluble solids, which precipitate when the fraction is diluted with water and which, according to mass equilibrium, must be comprised mostly of solubilized lignin. The highest concentrations of water-insoluble solids always occur in the first fraction and are almost absent after the first 10 fractions (see Figures 5A and 5B). The total mass of water-insoluble solids corresponded to 95% and 84% of the original lignin mass by extraction with 80 / 20% by weight and 90 / 10% by weight of GVL-to-water, respectively.

[0083] Quantitatively, the dilute lactone / water / acid process leads to a 5 to 20 percentage point increase in total C5 sugar recovery and, notably, a 2 to 4 modulation increase (200% to 400% increase) in C6 sugar recovery (see Figure 1F). It is also noteworthy that the yields of both C5 and C6 sugars are nearly identical for maple wood compared to corn straw. Again, see Figure 1F. This indicates that carbohydrate recovery depends on the type of substrate used. Furthermore, due to the fractionation concentration profile, C6 and C5 sugars are better dissolved when using a lactone / water solvent system. Despite the increased amount of sugars associated with GVL / water mixtures, more than 80% of the sugars extracted from C5 and C6 can be recovered in separate solvent fractions, in contrast to 75% for water and 65% for ethanol (these percentages were Petition 870200112396, dated 04 / 09 / 2020, p. 32 / 97 27 / 37 calculated as illustrated in Figures 6A to 6D; see Examples). The ability to separate C5 sugars from C6 sugars allows the use of C5 and C6 fractions in separate and distinct enhancement processes. Furthermore, given the carbohydrate extraction profile associated with lactone / water systems (i.e., most sugars were extracted once temperatures reached approximately 210°C to 220°C / 483° to 493°K), carbohydrate concentrations can be increased by reducing the temperature rise time without significantly reducing carbohydrate yields. This is due to the reduction in the volume of solvent flowing through the biomass. As shown in Figure 1E, soluble carbohydrate yields reduce to less than 4% when the temperature rise is reduced from 2 hours to 1 hour.Reducing the temperature rise time to 30 minutes reduces the yield of soluble carbohydrate to less than 10 percentage points (when compared to a rise time of 2 hours).

[0084] The data shown in Figures 1A through 1F show that the lactone / water / dilute acid system favors the hydrolysis of hemicellulose and cellulose in contrast to traditional solvents such as water and water / ethanol mixtures. An important feature of GVL / water solvent systems is that the aqueous phase can be separated from the GVL by the addition of salt16. In Figures 2A, 2B, and 2C, carbohydrate recovery in the aqueous phase is shown as a function of NaCl content (NaCl is exemplary; any non-reactive salt or solute that leads to partitioning of the product mixture into an aqueous layer and an organic layer containing most of the lactone can be used). When using simulated carbohydrate feeds in the GVL / water mixtures, the data show that there was a trade-off between obtaining high aqueous carbohydrate concentrations at low levels of NaCl addition (e.g., 4% water) and recovery of Petition 870200112396, dated 04 / 09 / 2020, p. 33 / 97 28 / 37 carbohydrates elevated in the aqueous phase with higher salt levels (10 to 12% water. See Examples for more details. This exchange is illustrated in Figures 2A, 2B and 2C for corn straw-derived feeds. By recovering 40 to 50% of the sugars in the aqueous phase, glucose and xylose concentrations can be increased by about 10 to 20 modulation to 80 / 20 GVL / water and 90 / 10 GVL / water, respectively. The higher concentrations (above 110 g / l) are in a range of the highest concentrations obtained without any drying from pretreatment and enzymatic hydrolysis, which vary between about 150 to 200 g / l depending on the substrate and enzyme loading17'18. GVL / water and 90 / 10 GVL / water, the carbohydrate concentration drops to 25 g / l 60 g / l, respectively.Furthermore, concentrations can easily be increased by removing the first and last fractions from the flow process, which contained very few sugars. As shown in Figure 2C, while preserving the fractions that still contain 97% of both C5 and C6 sugars, carbohydrate concentrations can be increased from 25 g / l to 33 g / l simply by discarding the low-concentration fractions in the 80 / 20 GVL fractionation product. This 33 g / l solution was used in the carbohydrate enhancement experiments for monomers and furans, discussed below.

[0085] As discussed earlier, carbohydrate concentrations can also be increased by reducing the temperature ramp time. As shown in Figure 2C, using 80 / 20 GVL and a 12% aqueous NaCl content, carbohydrate concentrations increase to 48 g / l and 72 g / l with a temperature ramp of 1 hour and 30 minutes respectively, with recovery efficiencies around 90% and 80%. Petition 870200112396, dated 04 / 09 / 2020, p. 34 / 97 29 / 37

[0086] Recovery was slightly reduced in biomass-derived feeds compared to simulated monosaccharide-based feeds. See Figures 7A and 7B, and the Examples. This was mainly due to oligomers being more readily broken down in the organic phase than monomers. Furthermore, NaCl proved to be less soluble in biomass-derived feeds, with saturation at 90 / 10 GVL occurring between approximately 10 and 12 wt% water, whereas NaCl saturation occurred at approximately 16 wt% water in the simulated feeds.

[0087] As shown in Figures 2A, 2B, and 2C, the carbohydrates recovered in the aqueous phase are a mixture of monomers and oligomers. For bio-enhancing, monomers are preferred starting products, especially compared to oligomers with a degree of polymerization greater than two. However, due to the fact that the acid catalyst is recovered in the separate aqueous phase (during the use of homogeneous acid catalysts such as mineral acids), it offers an acidic aqueous environment that is well suited for oligomer depolymerization19. The data in Figure 3A show that by heating the unmodified aqueous phase separated from the 80 / 20 GVL product stream, more than 95% of total C5 and C6 sugars can be recovered in the form of monomers after treatment at approximately 140°C for 100 minutes. These monosaccharides are ideal substrates for bio-enhancing.

[0088] Carbohydrates can also be enhanced for fuels and useful chemicals via the furan platform20-22. Xylose and glucose can undergo dehydration to furfural and 5-hydroxymethylfurfural (5-HMF), respectively. Both of these species are unstable at high temperatures in acidic environments and benefit from continuous extraction in an organic phase such as 2 Petition 870200112396, dated 04 / 09 / 2020, page 35 / 97 30 / 37 sec-butylphenol (SBP) during the reaction23. Additionally, the selectivity for 5-HMF from glucose is greatly improved after glucose is isomerized to fructose, which can be catalyzed with a Lewis acid such as AlCh23. Phase modifiers such as NaCl further promote 5-HMF production by modifying its partition coefficient for the organic phase21-23.

[0089] In Figure 3B, yields of 5-HMF and furfural are shown as a function of reaction time at 170 °C from soluble carbohydrates (monomers and oligomers) recovered from the separated aqueous phase of 80 / 20 GVL. This phase was used unmodified except for the addition of A1C13 and the presence of the organic phase of SBP. Yields above 60 and 70% for 5-HMF and furfural, respectively, are almost identical to those obtained from glucose and xylose despite the presence of oligomers and other biomass byproducts23,24.

[0090] Due to the fact that the moderate conditions used to produce these sugars and the demonstrated versatility of these biomass-derived carbohydrates (suitable for both biological and chemical enhancement), this present method can be used in numerous biofuel and bioproduct production processes that utilize glucose, xylose, or water-soluble oligomers comprising glucose and / or xylose as a reagent to be added or a reagent to be consumed. EXAMPLES

[0091] The following Examples are included solely to provide a fuller disclosure of the method described and claimed herein. The Examples do not limit the scope of the claimed method in any way. The Examples provide the experimental methods by which the results presented in Figures 1A to 1F, 2A to 2C, 3A, 3B, 5A, 5B, 6A to 6D, 7A and 7B are formed Petition 870200112396, dated 04 / 09 / 2020, page 36 / 97 31 / 37 obtained. PASS-THROUGH REACTOR:

[0092] A schematic representation of the flow reaction system used in the Examples is shown in Figure 4. Corn straw was obtained from Great Lakes Bioenergy Research Center (GLBRC, Madison, WI) and maple wood was obtained from Mascoma (Hanover, NH). Their compositions are given in Table 1. TABLE 1: BIOMASS COMPOSITION Glucan [% by weight] Xylan [% by weight] Lignin Klason [% by weight] Corn straw 35.10 22.20 16.20 Maple wood 41.90 19.30 24.90

[0093] Approximately 2.5 g of biomass were mixed with 5 g of silicon dioxide granules (Sigma-Aldrich, St. Louis, MO) and placed in the heated zone of the through-flow reactor between two beds of pure silicon dioxide granules separated by quartz wool plugs (Grace-Davison, Albany, OU). See Figure 4. The heated zone of the reactor is filled between two aluminum blocks placed inside an insulated furnace (Applied Test Systems, Butler, PA). A type K thermocouple (Omega Engineering, Inc., Stamford, CT) was placed on the reactor wall and was used to monitor and control the reactor temperature using a 16A series controller (Love Controls, a division of Dwyer Instruments, Inc., Michigan City, IN). The solvent was flowed through the system using an HPLC pump as shown at the top of Figure 4 (Lab Alliance Series I, Thermo-Fischer Scientific, Waltham, MA).The pressure was kept constant at 2.068 MPa (300 psi) by flowing helium (Airgas, West Chicago, IL) into the liquid manifold clearance through a backpressure regulator (1,500 psi, 10.3 MPa, Tescom, a subsidiary). Petition 870200112396, dated 04 / 09 / 2020, page 37 / 97 32 / 37 integral of Emerson Process Management, Elk River, MN). At the beginning of the reaction, the dry biomass was heated to 149.85 °C (423 K) in the presence of helium using a 20-minute ramp. The temperature was allowed to equilibrate between 423 and 433 °C for 3 minutes, after which solvent was flowed through the biomass at a rate of 2 ml / min while a 2-hour temperature ramp was applied between 159.85 °C (433 K) and 219.85 °C (493 K). Samples of the passing liquid were collected approximately every 5 minutes, and the liquid collector was dried. Aqueous Phase Separation:

[0094] A given quantity of sodium chloride (Sigma-Aldrich) was added to the liquids resulting from the flow-through experiments using GVL-H2O mixtures as a solvent in order to separate the aqueous phase. The resulting solutions were repeatedly stirred and sonicated in a sonication bath (FS28, FisherScientific) until no solids were visible. The mixtures were then centrifuged at 4,500 rpm for 4 minutes in a Sorvall ST16 centrifuge (ThermoFisher). The heavier aqueous phase was removed using a syringe and needle to measure its mass, after which both phases were analyzed. MONOMER PRODUCTION:

[0095] Oligomer depolymerization reactions were carried out in thick-walled glass reactors (5 mm, Supelco, a subsidiary of Sigma-Aldrich, Bellefonte, PA) with a magnetic stirrer. Approximately 2.5 g of unmodified aqueous solutions resulting from aqueous phase separation were placed in the reactors. The glass reactors were heated and stirred using an oil bath at 139.85°C (413°K) placed on an Isotemp digital hot plate stirrer set at 800 rpm (Fisher Scientific). The reactors were stopped at specific reaction times. Petition 870200112396, dated 04 / 09 / 2020, page 38 / 97 33 / 37 fixed by placing the reactors in a fluid ice paste. FURAN PRODUCTION:

[0096] Aqueous solutions (1.5 g each) resulting from aqueous phase separation to which 100 mM AlCl3 (Sigma-Aldrich) was added were contacted with 3 g of 2-sec-butylphenol (Alfa-Aesar, a Johnson Matthey Company, Ward Hill, MA) in a 10 ml thick-walled glass reactor (Grace Davison). To initiate each reaction, the resulting mixture was placed in a heated oil bath with an Isotemp digital hot plate stirrer (Fisher Scientific). The hot plate was used to stir a magnetic stir bar in the reactor at 1200 rpm. Similar to the monomer production experiments, the reactors were cooled to specific reaction times by placing them in a fluid ice paste. ANALYTICAL METHODS:

[0097] The aqueous phase, GVL / water and ethanol / H2O, were analyzed for glucose, xylose, 5-hydroxymethylfurfural (HMF), and furfural after 10 dilutions in water using a Waters 2695 HPLC system with a Bio-Rad Aminex HPX-87H column and a 5 mM H2SO4 mobile phase flowing at 0.6 ml / min (Waters, Inc., Milford, MA; Bio-Rad Laboratories, Inc., Hercules, CA). The 2-sec-butylphenol phase was analyzed using a Waters 2695 HPLC system with a 5 μm Zorbax SB-C18 5 column (Agilent, Santa Clara, CA) using 5 mM H2SO4 as the aqueous phase with acetonitrile as the organic modifier. Both systems were equipped with an RI 2414 (refractive index) detector and a Waters PDA 960 (photodiode array) detector. Sugars were measured using the RI detector, while 5-HMF and furfural were measured using the PDA detector at 320 and 230 nm, respectively. Oligomers were measured according to the procedure published by the National Renewable Energy Laboratory.19 Petition 870200112396, dated 04 / 09 / 2020, page 39 / 97 34 / 37 Use of 10 ml thick-walled glass reactors (Grace-Davison) placed in an oil bath at 121°C.

[0098] Water-insoluble solids in GVL / water fractions were measured by diluting the solutions 10 times with water and filtering the resulting mixture using a 0.2 μm nylon filter (Millipore, Billerica, MA). The filter was dried overnight in a vacuum oven (Fisher-Scientific) set at 59.85°C (333°K) and weighed for recovered solids. OPTIMIZATION OF AQUEOUS PHASE SEPARATION:

[0099] Two simulated feedings (80% by weight of GVL for Solutions (80 wt. GVL / 20 wt. GVL / 90 wt. GVL / 10 wt. GVL) were constructed based on corn straw fractionation results. Given amounts of glucose and xylose, equivalent to the amounts of their equivalent monomer and oligomer concentrations in the corn straw-derived solutions, were added to the respective solvent. The effect of increasing NaCl concentrations on aqueous phase separation is shown in Figures 7A (80 wt. GVL / 20 wt. GVL / 20 wt. GVL) and 7B (90 wt. GVL / 10 wt. GVL). The solution containing 80 wt. GVL showed salt saturation between 16 and 20 wt. NaCl (i.e., mass fraction relative to the total amount of water present), while the solution containing 90 wt. GVL showed saturation between 12 and 16 wt. NaCl. REFERENCES CITED

[00100] The following documents are incorporated by reference. 1. Somerville, C. The Billion-Ton Biofuels Vision. Science 312, 1.277 (2006). 2. Sanderson, K. Lignocellulose: A chewy problem. Nature Petição 870200112396, de 04 / 09 / 2020, pág. 40 / 97 35 / 37 474, S12 (2011). 3. Ragauskas, A. J. et al. The Path Forward for Biofuels and Biomaterials. Science 311,484 a 489 (2006). 4. Lynd, L. R. et al. How biotech can transform biofuels. Nat. Biotech. 26, 169 a 172 (2008). 5. Von Sivers, M. & Zacchi, G. A techno-economical comparison of three processes for the production of ethanol from pine. Bioresource Technology 51,43 a 52 (1995). 6. Wilson, D. B. Cellulases and biofuels. Current opinion in biotechnology 20, 295 a 299 (2009). 7. Houghton, J. Breaking the biological barriers to cellulosic ethanol: A joint research agenda. (US Department of Energy, 2005). em <http: / / www.doegenomestolife.org / biofuels> 8. Binder, J. B. & Raines, R. T. Fermentable sugars by chemical hydrolysis of biomass. Proceedings of the National Academy of Sciences 107, 4.516 a 4.521 (2010). 9. Bobleter, O. Hydrothermal Degradation Of Polymers Derived From Plants. Progress In Polymer Science 19, 797 a 841 (1994). 10. Peterson, A. A. et al. Thermochemical biofuel production in hydrothermal media: A review of sub- and supercritical water technologies. Energy Environ. Sci. 1, 32-65 (2008). 11. Shill, K. et al. Ionic liquid pretreatment of cellulosic biomass: Enzymatic hydrolysis and ionic liquid recycle. Biotechnology and Bioengineering 108, 511 a 520 (2011). 12. Lee, Y. Y., Iyer, P. & Torget, R. W.in Recent Progress in Byconversion of Lignocellulosics (Tsao, P. D. G. T. et al.) 93 a 115 (Springer Berlin Heidelberg, 1999). Em <http: / / link.springer.com / chapter / 10.1007 / 3-540-49194-5_5> 13. Liu, C. G. & Wyman, C. E. The effect of flow rate of very dilute sulfuric acid on xylan, lignin, and total mass removal from corn Petição 870200112396, de 04 / 09 / 2020, pág. 41 / 97 36 / 37 stover. Industrial & Engineering Chemistry Research 43, 2.781 a 2.788 (2004). 14. Giirbuz, E. I. et al. Conversion of Hemicellulose into Furfural Using Solid Acid Catalysts in γ-Valerolactone. Angewandte Chemie International Edition n / a-n / a (2012).doi : 10.1002 / anie.201207334 15. Alonso, D. M, Wettstein, S. G., Mellmer, M. A., Gurbuz, E. I. & Dumesic, J. A. Integrated conversion of hemicellulose and cellulose from lignocellulosic biomass. Energy Environ. Sci. (2012).doi:10.1039 / C2EE23617F 16. Wettstein, S. G., Alonso, D. M, Chong, Y. & Dumesic, J. A. Production of levulinic acid and gamma-valerolactone (GVL) from cellulose using GVL as a solvent in biphasic systems. Energy Environ. Sci. 5, 8.199 a 8.203 (2012). 17. Luterbacher, J. S., Chew, Q., Li, Y., Tester, J. W. & Walker, L. P. Producing concentrated solutions of monosaccharides using biphasic C02-H20 mixtures. Energy Environ. Sci. 5, 6.990 a 7.000 (2012). 18. Hodge, D. B., Karim, M. N., Schell, D. J. & McMillan, J. D. Soluble and insoluble solids contributions to high-solids enzymatic hydrolysis of lignocellulose. Bioresour. Technol. 99, 8.940 a 8.948 (2008). 19. Sluiter, A. et al. Determination of sugars, byproducts, and degradation products in liquid fraction process samples. (National Renewable Energy Laboratory, 2004). 20. Lange, J. -P., Van der Heide, E., Van Buijtenen, J. & Price, R. Furfural— A Promising Platform for Lignocellulosic Biofuels. ChemSusChem 5, 150 a 166 (2012). 21. Roman-Leshkov, Y., Chheda, J. N. & Dumesic, J. A. Phase modifiers promote efficient production of hydroxymethylfurfural Petição 870200112396, de 04 / 09 / 2020, pág. 42 / 97 37 / 37 from fructose. Science 312, 1933 (2006). 22. Roman-Leshkov, Y., Barrett, C. J., Liu, Z. Y. & Dumesic, J. A. Production of dimethylfuran for liquid fuels from biomass-derived carbohydrates. Nature 441,982 a 985 (2007). 23. Pagan-Torres, Y. J., Wang, T., Gallo, J. M. R., Shanks, B. H. & Dumesic, J. A. Production of 5-Hydroxymethylfurfural from Glucose Using a Combination of Lewis and Bronsted Acid Catalysts in Water in a Biphasic Reactor with an Alkylphenol Solvent. ACS Catal. 2, 930 a 934 (2012). 24. Gurbuz, E. I., Alonso, D. M., Bond, J. Q. & Dumesic, J. A. Reactive extraction of levulinate esters and conversion to gammavalerolactone for production of liquid fuels. ChemSusChem 4, 357 a 361 (2011). Petição 870200112396, de 04 / 09 / 2020, pág. 43 / 97

Claims

1 / 4 CLAIMS 1. A method for producing an aqueous carbohydrate solution comprising C6 sugar-containing oligomers, C6 sugar monomers, C5 sugar-containing oligomers, C5 sugar monomers, or any combination thereof, wherein the method is characterized in that it comprises: (a) reacting biomass or a biomass-derived reagent with a solvent system comprising (i) an organic solvent selected from the group consisting of beta, gamma, and delta lactones and combinations thereof and (ii) at least 1% by weight of water;in the presence of an acid catalyst for a time and under conditions to produce a product mixture in which at least a portion of water-insoluble C6 sugar-containing polymers or oligomers, or water-insoluble C5 sugar-containing polymers or oligomers, if present in the biomass or biomass-derived reagent, are converted into water-soluble C6 sugar-containing oligomers, C6 sugar monomers, C5 sugar-containing oligomers, C5 sugar monomers, or any combination thereof; and then (b) adding a solute to the product mixture of step (a) in an amount sufficient to cause the product mixture to partition into an aqueous layer and an immiscible organic layer.

2. Method according to claim 1, characterized in that the organic solvent is miscible with water.

3. Method according to claim 1, characterized in that the organic solvent can dissolve from 2% by weight to 40% by weight of water.

4. Method, according to any one of claims 1 to 3, characterized in that the organic solvent is gamma valerolactone (GVL). Petition 870200112396, dated 04 / 09 / 2020, page 44 / 97 2 / 4 5. A method according to any one of claims 1 to 4, characterized in that the organic solvent is present in a mass ratio with water, organic solvent:water, selected from the group consisting of 60:40, 65:35, 70:30, 75:25, 80:20, 85:15, 90:10, 95:5, 97:3, 98:2 and 99:

1.

6. A method according to any one of claims 1 to 5, characterized in that the acid catalyst is homogeneous or heterogeneous and, if the acid catalyst is homogeneous, it is present in a concentration not greater than 100 mM based on the volume of the solvent system and, if the acid catalyst is heterogeneous, it is present in a concentration not greater than 1.0% by weight based on the weight of the solvent system.

7. A method according to any one of claims 1 to 6, characterized in that the acid catalyst is either a mineral acid or an organic acid.

8. A method according to any one of claims 1 to 6, characterized in that the acid catalyst is a solid acid catalyst selected from the group consisting of solid Bronsted acid catalysts, solid Lewis acid catalysts, and combinations thereof.

9. Method according to claim 8, characterized in that the solid acid catalyst is a heteropolyacid.

10. Method according to claim 8, characterized in that the solid acid catalyst is an amorphous or mesoporous silica, which can be defunctionalized or functionalized with an acid modifier.

11. Method according to claim 8, characterized in that the solid acid catalyst is a zeolite.

12. Method, according to any of the claims 1 to 11, characterized in that the solute is an inorganic salt soluble in water.

13. Method according to claim 12, characterized in that salt is added to the product mixture in a saturating amount.

14. Method according to claim 12, characterized in that the salt is sodium chloride.

15. Method, according to any one of claims 1 to 14, characterized in that step (a) is conducted in a temperature range selected from the group consisting of 100°C to 300°C, 140°C to 240°C and 150°C to 200°C.

16. Method, according to any one of claims 1 to 15, characterized in that step (a) is conducted in a dynamic temperature range.

17. Method according to claim 16, characterized in that the dynamic temperature range rises from a first temperature to a second temperature that is higher than the first temperature.

18. Method according to claim 16, characterized in that the dynamic temperature range changes from a first temperature to a second temperature in a non-linear manner, a discontinuous manner, or a combination thereof.

19. Method according to any one of claims 1 to 18, characterized in that in step (a) the biomass or a biomass-derived reagent comprises water-insoluble glucose-containing polymers or oligomers, or water-insoluble xylose-containing polymers or oligomers, or any combination thereof, and these, if present, are converted into water-soluble glucose-containing oligomers, glucose monomers, water-soluble xylose-containing oligomers, xylose monomers, or any combination thereof.

20. Method, according to any one of claims 1 to 19, characterized in that in step (a), the residence time of the reaction is selected from the group consisting of 1 min to 24 hours, 1 min to 20 hours, 1 min to 12 hours, 1 min to 6 hours, 1 min to 3 hours, 1 min to 2 hours, 1 min to 1 hour and 1 min to 30 min. Petition 870200112396, dated 04 / 09 / 2020, p. 47 / 97

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