Processes to create multiple value streams from biomass sources

MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY

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PROCESSES TO CREATE MULTIPLE VALUE STREAMS FROM BIOMASS SOURCES

MX/a/2018/009634

BACKGROUND OF THE INVENTION

The processing of biomass-derived hemicellulose hydrolysates for the production of specific alditols is complicated, inefficient, and expensive. There are, for example, significant difficulties in obtaining a significant extraction yield of high-purity alditol through the use of a hemicellulosic feedstock. There are continuous cascading losses associated with the various unit operations of purification and separation, among other process steps, performed in accordance with the established state of the art, which result in impaired efficiency and reduced scale of alditol recovery. Currently, sorbitol is made from single-stream C6 sugars, usually hydrogenated corn glucose, while xylitol is made from single-stream C5 sugars derived from larch or poplar trees. There remains a need in the art for a process that can use mixed C5/C6 sugar streams derived from diverse non-segregated hemicellulosic feedstocks to recover respective target C5/C6 alditols, in addition to, and if desired, target C2-C4 glycols.

Indeed, there remains a need in the art for an efficient, high-throughput process aimed at recovering high-purity alditols and other target coproducts derived from diverse biomass while minimizing inefficiencies and losses associated with additional downstream operations.

BRIEF DESCRIPTION OF THE INVENTION

In one embodiment, a process comprises optimizing an overall product recovery without boosting the maximum individual recovery of each product, wherein the products comprise a target alditol or target alditol mixture, and a target glycol or target glycol mixture. The process includes hydrogenating a mixed C5/C6 monomer sugar stream to form a mixed C5/C6 alditol stream; isolating a target alditol or mixture of target alditols from the mixed C5/C6 alditol stream to leave a residual mixed C5/C6 alditol stream; subjecting the residual mixed C5/C6 alditol stream to hydrogenolysis to form a mixed C2-C4 glycol stream; and isolating a target glycol or mixture of target glycols from the mixed C2-C4 glycol stream; wherein at least 10% of the overall target product yield is target alditol/target alditol mixture or target glycol/target glycol mixture.

In another embodiment, a process comprises optimizing a product recovery

<img file="MX391237B_D0001.tif" />

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Mexican Institute of Industrial Property general without promoting the maximum individual recovery of each product, wherein the products comprise xylitol and a target glycol or target glycol mixture, the process comprising: hydrogenating a C5/C6 mixed monomer sugar stream to form a C5/C6 mixed alditol stream; isolating xylitol from the C5/C6 mixed alditol stream to leave a residual C5/C6 mixed alditol stream; subjecting the residual mixed C5/C6 alditol stream to hydrogenolysis to form a mixed C2-C4 glycol stream; and isolating a target glycol or target glycol mixture from the mixed C2-C4 glycol stream; wherein at least 10% of the overall target product yield is xylitol or target glycol or target glycol mixture.

In yet another embodiment, a process comprises synergistically improving overall product recovery without the need to boost the individual total recovery of each product, wherein the products comprise a target C5/C6 monomer sugar or target C5/C6 monomer sugar mixture, and a target glycol or target glycol mixture, the process comprising isolating a target C5/C6 monomer sugar or target C5/C6 monomer sugar mixture from a mixed C5/C6 monomer sugar stream to form a residual mixed C5/C6 monomer sugar stream; subjecting the residual mixed C5/C6 monomer sugar stream to hydrogenolysis to form a mixed C2-C4 glycol stream; and isolating a target glycol or target glycol mixture from the mixed C2-C4 glycol stream; wherein at least 10% of the overall target product yield is target C5/C6 monomer sugar/target C5/C6 monomer sugar mixture or target glycol/target glycol mixture.

In another embodiment, a process comprises hydrogenating a monomer sugar stream to form a mixed alditol stream; recovering a target alditol or mixture of target alditols from the mixed alditol stream to leave a residual mixed alditol stream; and subjecting the residual mixed alditol stream to hydrogenolysis to form a mixed C2-C4 glycol stream.

In another embodiment, a process comprises hydrogenating a monomer sugar stream to form a mixed alditol stream; recovering a target alditol or mixture of target alditols from the mixed alditol stream to leave a residual mixed alditol stream; subjecting the residual mixed alditol stream to hydrogenolysis to form a mixed C2-C4 glycol stream; and recovering a target glycol or mixture of target glycols from the mixed C2-C4 glycol stream.

In another embodiment, a process comprises hydrogenating a mixed C5/C6 monomer sugar stream to form a mixed C5/C6 alditol stream; recovering a target alditol or mixture of target alditols from the mixed C5/C6 alditol stream to leave a residual mixed C5/C6 alditol stream; and subjecting the residual mixed C5/C6 alditol stream to hydrogenolysis to form a mixed C2-C4 glycol stream.

In another embodiment, a process comprises hydrogenating a mixed C5/C6 monomer sugar stream to form a mixed C5/C6 alditol stream; recovering a target alditol or

MX/a/2018/009634

<img file="MX391237B_D0002.tif" />

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Mexican Institute of Industrial Property mixture of target alditols from the mixed C5/C6 alditol stream to leave a residual mixed C5/C6 alditol stream; subjecting the residual mixed C5/C6 alditol stream to hydrogenolysis to form a mixed C2-C4 glycol stream; and recovering a target glycol or target glycol mixture from the mixed C2-C4 glycol stream.

In another embodiment, a process comprises recovering at least one target monomer sugar from a mixed monomer sugar stream to leave a residual mixed monomer sugar stream; hydrogenating the recovered target monomer sugar to form at least one target alditol; hydrogenating at least a portion of the residual mixed monomer sugar stream to form a mixed alditol stream; and subjecting the mixed alditol stream to hydrogenolysis to form a mixed C2-C4 glycol stream.

In another embodiment, a process comprises selecting a target alditol or a mixture of target alditols, continuously hydrogenating a mixed C5/C6 monomer sugar stream to form a mixed C5/C6 alditol stream; isolating the target alditol or mixture of target alditols from the mixed C5/C6 alditol stream to leave a residual mixed C5/C6 alditol stream; continuously hydrogenolyzing the residual mixed C5/C6 alditol stream to form a mixed C2-C4 glycol stream; and isolating a target glycol or target glycol mixture from the mixed C2-C4 glycol stream; wherein at least 10% of the overall target product yield is target alditol/target alditol mixture or target glycol/target glycol mixture.

As used herein, the term "alditol" shall be synonymous with polyhydric alcohol, sugar polyol, and sugar alcohol. Arabitol, arabinol, arabinitol, and lixitol are synonyms. Illustrative alditols produced by the described processes include xylitol, sorbitol, and the like. Illustrative five-carbon (C5) alditols include arabitol, ribitol, and xylitol. Illustrative six-carbon (C6) alditols include alitol, galactitol, iditol, mannitol, sorbitol, and tallitol. C5/C6 alditols include a mixture of alditols having any ratio of C5 to C6 alditols. C5/C6 sugar monomer means a mixture of monomer sugars (i.e., monosaccharides) having any ratio of a five-carbon (C5) monosaccharide (pentose) to a six-carbon (C6) monosaccharide (hexose). Illustrative C5 and C6 monosaccharides include those derived from plant biomass, specifically, arabinose, lyxose, ribose, ribulose, xylose and xylulose, and C6 sugars, such as fructose and glucose.

Glycol means a molecule that has two hydroxyl (OH) groups attached to different carbon atoms. Two-carbon (C2), three-carbon (C3), and four-carbon (C4) glycols include isomers of ethylene glycol, propylene glycol, and butanediol, respectively.

As used herein, the terms comprising (in addition, comprises, etc.), having, and including are inclusive (open-ended) and do not exclude elements or

MX/a/2018/009634 stages of additional procedures not mentioned. The singular forms un, una, el, and la

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MEXICAN INSTITUTE^F OF THE PROPERTY w

INDUSTRIAL includes plural referents, unless the context clearly indicates otherwise. The endpoints of all intervals referring to the same feature or component may be combined independently and include the listed endpoint. The term "a combination" includes two or more of the listed components. The term "homogeneous" refers to a uniform mixture of the components. The terms first, second, and the like, primary, secondary, and the like, as used herein, do not indicate order, quantity, or importance, but are used to distinguish one element from another. As used in the Tables, N/A means not applicable; ND means not detected; and TR means trace.

BRIEF DESCRIPTION OF THE FIGURES

The attached figures that are incorporated and form part of the specification include:

Figure 1 is an illustrative process flow diagram for a biomass front end stage (20) including biomass deconstruction (1) of biomass feedstock (100), biomass fractionation (2), lignin recovery (3), hemicellulose oligomers converted to monosaccharides (4), and optional monosaccharide isolation (5).

Figure 2 is a process flow diagram for the separation and crystallization step (40) including target alditol extraction (10) from hydrogenation feed 20 (30), enhanced alditol extraction (11), further alditol extraction (12), and alditol equilibrium (13).

Figure 3 is a process flow diagram for the hydrogenolysis and separation stage (50) including hydrogenolysis (14) and glycol separations (15).

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure describes unexpectedly synergistic and beneficial processes aimed at the recovery of alditol and/or glycol from biomass bearing diverse hemicelluloses. Typically, conventional xylitol production focuses on single xylitol recovery from a single stream feedstock where recovery is complicated, expensive, inefficient and difficult to achieve high purity due to high levels of non-xylose organic aldose compounds such as lignin and ash. The majority of the global xylitol industry, for example, predominantly uses corn cob or larch/poplar-based xylose feedstock that requires extensive purification processing to drive hydrogenation operations for total xylitol recovery at substantial time, expense, and complexity. Similarly, a significant amount of global production

MX/a/2018/009634

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Mexican Institute of Industrial Property of ethylene glycol and propylene glycol uses only fossil fuel feedstocks, such as petroleum or natural gas. Glycol production currently does not allow for large-scale commercial use of non-fossil fuel feedstocks, such as cellulose biomass. These traditional manufacturing processes do not allow for the independent use of various feedstock raw materials nor do they allow for the on-line recovery and conversion of hydrogenation co-products.

Contrary to the current state of the art, the processes of the invention described allow the use of various independent non-segregated or segregated feedstocks. For example, the processes of the invention may use a single non-segregated feedstock composed of wheat straw, hardwood, and beet, and furthermore, the processes may further use alternating single segregated feedstocks of wheat straw, hardwood, or beet depending on supply availability, price fluctuations, or the like. Therefore, the feedstock neutral processes described avoid dependence on expensive, limited-supply, exotic feedstock for inefficient conversion while also increasing efficiency through the recovery and conversion of hydrogenation coproducts. Indeed, the embodiments described herein depart from the existing art to maximize overall yield and dramatically improve overall plant flexibility and operational efficiency. Current methods of, for example, producing xylose and/or xylitol

MX/a/2018/009634 focus on maximizing throughput and minimizing waste, from a given mass of feedstock, and may use multiple recovery and operation loops – with decreasing efficiency and throughput per operation – to boost production. Similarly, several processes directed at the production of glycols (from sugars, alditol, glycerol, or the like) additionally focus operations on maximizing glycol yield to minimize waste through the use of continuously inefficient, continuously cascaded operating loops. The numerous processes described herein take learned approaches contrary to the art by not maximizing xylitol or glycol yield individually. In contrast, the processes described synergistically optimize the overall yield by first recovering an initial fraction of xylitol while allowing the remainder to be converted into glycol. Therefore, the xylitol yield is reduced because part of the xylitol that would have been recovered by the existing technique is converted into glycol. The glycol yield is further reduced because part of the xylitol that could have been converted into glycol is recovered as xylitol. The yield of xylitol or glycol is apparently suboptimal and severely underestimated by current technology. However, unexpectedly and synergistically, the described process modalities actually promote a higher total combined yield of xylitol and glycol (rather than individual, compensatory yields), thereby increasing plant efficiency. As described herein,

<img file="MX391237B_D0004.tif" />

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MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY description, the processes are not limited to the production of xylitol and glycol.

Thus, in this way, multiple product streams of interest - for example,

MX/a/2018/009634 xylitol and propylene glycol; sorbitol and ethylene glycol; or a mixture of xylose/sorbitol and butanediols—can be recovered without the typical limitations of driving maximum performance of any individual target product component negatively impacting overall efficacy, cost, and waste generation.

In a general embodiment, the process comprises selecting at least two target products based on a feed load source such that the overall product yield of the at least two target products is such that the process is more efficient than if one were to attempt to maximize the yield of only a single product. The feedstock source may be a biomass feedstock, a hydrolysate stream, a monomer sugar stream, or a combination thereof, as described in greater detail herein. In one embodiment, at least 90% of the feedstock source is converted to target alditols and glycols. In one embodiment, the power load source becomes the at least two target products wherein at least 10% of the overall target product yield is one of the at least two target products, more specifically, at least 15%, at least 20%, or at least 25% of the overall target product yield. If the overall target product performance needs to be maintained, the process further comprises modifying the selection of at least two target products if there is a change in the power load source. The at least two target products may be a target [C5/C6] alditol, a target [C5/C6] alditol mixture, a target [C5/C6] monomer sugar, a target [C5/C6] monomer sugar mixture, a target C2-C4 glycol, a target C2-C4 glycol mixture, an organic acid, a compound in Table 1A herein, or a combination thereof, and specifically, wherein at least one of the target products is a target C2-C4 glycol or a target C2-C4 glycol mixture. Furthermore, within this embodiment, the number of operating loops or operational treatments is performed no more than two or three times in any single feedstock stream, specifically, no more than two times, and more specifically, once. The operational processing loop may be a hydrogenation, hydrogenolysis, biomass deconstruction process, or isolation process as described herein. The feedstock stream may be any initial feedstock stream or intermediate feedstock stream created in the process. Illustrative feedstock streams include a biomass feedstock stream, a hydrolysate stream, a monomer sugar stream, an alditol stream, a glycol stream, or a combination thereof, as described herein. In a further embodiment, a feedstock stream may be modified or augmented with external material to change the composition of the feedstock stream.

More specifically, described herein is an embodiment directed to conditioning C5 sugars from C5-containing monomer sugar streams that may be derived from a variety of biomass sources and converting those conditioned (purified) sugars into specific target alditols via hydrogenation and into specific target glycols via hydrogenolysis. The process may be directed toward the production of target C5/C6 alditols and target C2-C4 glycols from biomass-derived mixed C5/C6 sugar streams, overcoming the efficiency and total product yield challenges of the prior art. Alternatively, a process may be directed toward conditioning a C5 monomer sugar stream so that the C5 stream may contain 2-4 carbon sugars, 6-12 carbon sugars, glycerol, glycols, impurities, or the like. Alternatively, a process is directed to the conditioning of mixed C5 and C6 sugars at varying C5/C6 ratios derived from various biomass sources and the isolation of a target monomer sugar (e.g., xylose) or a mixture of target monomer sugars with the residual material converted to specific target glycols via hydrogenolysis. Such described processes, which include either hydrogenation or hydrogenolysis, may be batch or continuous. In any number of embodiments, additional aldltol may be provided to the hydrogenolysis of the residual mixed C5/C6 aldltol stream to form a mixed C2-C4 glycol stream.

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The generation of alditols and glycols as co-products is achieved by combining hydrogenation of hemicellulose-based C5/C6 monomer hydrollates to alditols with downstream hydrogenolysis of the residual materials after crystallization/elimination of the target alditol to produce glycols. In summary, after hydrogenation of aldoses to alditols and target alditol(s), many residual materials, including non-target alditols, can be converted into glycol products.

The suitable biomass feedstock should provide a mixture of monosaccharides that, when hydrogenated, can produce a variety of alditols. Accordingly, but not limited to, various sources such as wheat straw, bagasse, sulfite pulp liquor, hardwood, hybrid poplar, grasses, sugarcane, beet, starch, etc. can be used as feedstock for the inventive processes described herein. After hydrolysis, the hydrolyzed solution provides a monomer sugar stream, the stream, for example, having at least one C5 sugar, at least one C6 sugar, or combinations thereof (mixed monomer sugar stream). The hydrolyzed mixed monomer sugar stream may be purified and then hydrogenated to produce a mixed aldol stream, containing more than one aldol, such as any combination of xylitol, mannitol, and sorbitol (mixed aldol stream). Target alditols, such as xylitol and/or sorbitol, can be recovered from the

<img file="MX391237B_D0005.tif" />

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Mexican Institute of Industrial Property solution by, for example, crystallization or chromatography. These target alditols can be recovered at high purities suitable for food applications. The hydrolyzed solution components not recovered by the alditol isolation step (the residual mixed alditol stream) can then be subjected to further hydrogenolysis to recover industrial or food-grade glycols. Optionally, additional alditols may be recovered after, or before, the target alditol crystallization, if desired, instead of being treated to produce glycol, in accordance with the principle of balanced overall total product or stoichiometric value and recovery.

The components of the hydrolysate stream obtained by the deconstruction and hydrolysis of the biomass feedstock can be chemically and/or physically characterized. These include: percentage by dry weight of each component of the hydrolysate stream, ratio of C5 to C6 sugars in the hydrolysate stream, and ratio of xylose and/or arabinose to total C5 sugars in the hydrolysate stream. From this information, the designed recovery balance of target materials in their respective forms is determined by calculation to provide an optimal overall total product or stoichiometric recovery value. Many target alditols and target glycols can be produced using this process. One method for calculating the optimal overall total product or stoichiometric recovery value could be to weigh the target alditol yield against the target glycol yield. For example, in one embodiment, xylitol is removed from the main stream after the hydrolyzate stream has undergone hydrogenation. After further processing, propylene glycol is purified from the stream. The relationship between xylitol yield and propylene glycol yield is measured and adjusted by modifying process parameters and conditions, biomass feedstocks, addition of other C5/C6 sources, etc., to obtain an optimized overall total product yield (compared to individual and compensatory yields) or stoichiometric recovery value. The same can be practiced with arabitol as the target alditol and ethylene glycol as the target glycol, or any combination of any alditol as the target alditol and any glycol as the target glycol, including mixtures or combinations of glycols as the target glycol and mixtures or combinations of alditols. For example, a mixture of xylitol and sorbitol could be made up as the target alditol, and a mixture of propylene glycol and ethylene glycol could be made up as the target glycol.

When xylitol is a target alditol, the selection of suitable biomass feedstock composition and structure for the described process may include a high ratio of xylose sugar derivatives compared to other sugar derivatives, and ease of accessibility to extract the xylose sugar derivatives over the other components.

A high ratio of xylitol compared to other alditols is exemplified

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<img file="MX391237B_D0006.tif" />

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Mexican Institute of Industrial Property by xylitol, which has a concentration greater than or equal to 80% of the total alditol concentration. Therefore, a concentrated solution at 80% w/w of total sugar-derived solids, with >80% of those solids being xylitol, will have a net concentration of >=64% xylitol. A xylitol concentration greater than or equal to 90% of the total alditol concentration provides a net concentration of 72%, providing even higher yields. When xylitol is the target alditol, the total C5 sugar content of the feedstock is specifically greater than 25%, specifically greater than 60%, and more specifically greater than 90%. In the same embodiment, the xylose content of the feedstock is, specifically, greater than 20%, more specifically, greater than 50%, and even more specifically, greater than 80%.

Suitable hydrogenation of aldoses, such as those in a mixed C5/C6 monomer sugar stream, may also include process steps that facilitate the removal of ash, non-sugar organic compounds, and other inorganic species, such as phosphates and chloride anions. Biomass feedstock pretreatment and the use of activated carbon may be used. The biomass feedstock can be converted into a useful C5 monomer sugar stream by deconstruction through a variety of thermomechanical, alkaline, enzymatic, or acid hydrogenation operations. The C5 monomer sugar stream can optionally contain 2-4 carbon sugars, 6-12 carbon sugars, glycerol, glycols, impurities, or the like. In addition, an optionally additional clean C5 stream may be provided by subjecting a C5 stream to any number of downstream operations, such as, by way of example, but not limited to, fractionation, lignin recovery, monosaccharide isolation, and organic/inorganic impurity removal operations as shown in Figure 1. In this way, among other benefits, the operating life of the catalyst can be extended and impurities that inhibit alditol crystallization can be minimized.

Facilitating the crystallization of xylitol (as an illustrative target alditol product) may involve establishing and supplying threshold concentration levels of xylitol (minimum concentrations) and other alditols (maximum concentrations) to enable recovery of xylitol in efficient yield and with purity suitable for premium applications. Additional details are described in the Enhanced Alditol Extraction section below.

Crystallization of a target alditol product can also be facilitated by the optional use of an antisolvent (e.g., ethanol or isopropanol) to increase the crystallization yield of the alditol. Such an antisolvent can also improve the ease of solid-liquid separation and filtration times.

In one embodiment, a process comprises purifying a mixed C5/C6 monomer sugar stream derived from a single biomass source to form a mixed monomer sugar stream.

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Purified mixed C5/C6, converting the purified mixed C5/C6 monomer sugar stream into C5/C6 alditols through hydrogenation; fractionating the C5/C6 alditols individually or purifying all or part of the C5/C6 alditols, and forming a residual mixed C5/C6 alditol stream (minus target alditols). The residual mixed C5/C6 alditol stream (minus target alditols) is converted into a hydrogenolysis feedstock for glycols. Target alditol products can be removed as crystals (solids) or liquid concentrates.

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In one embodiment, a process comprises purifying a monomer sugar stream

C5/C6 mixed derived from a diverse biomass source and combining the purified mixture with C5/C6 monomer sugars (with, for example, significantly increased C5 levels) and adding these concentrated aldoses to existing C5/C6 monomer sugar sources to enhance the target C5 or C6 aldoses and converting the purified mixed C5/C6 and/or increased aldose sugar stream into C5/C6 alditols via hydrogenation; and fractionating the C5/C6 alditols individually or purifying all or part of the C5/C6 alditols. Furthermore, the concentrated C5/C6 aldose streams could further be selectively hydrogenated to mixed alditols with target alditols removed by crystallization, etc., and then external alditols (such as glycerin) added to the residual mixed C5/C6 alditol stream prior to hydrogenolysis. As used herein, glycerin is the same as glycerol.

In one embodiment, streams rich in external C5 monomers (from any source) can be added to the mixed C5/C6 monomer sugar stream derived from a single or diverse biomass source to increase the C5/C6 monomer sugar ratios prior to hydrogenation and, thereafter, the extracted target alditol(s). Additional external non-target alditols (such as C3 glycerol or C6 sorbitol) can be added after hydrogenation and target alditol removal to increase the downstream hydrogenolysis conversion to glycols.

The integrated process for producing target alditols and target glycols as co-products involves the unique combination of hydrogenation of hemicellulose hydrolysates to alditols (mother liquor) followed by removal of target alditols from the mother liquor with downstream hydrogenolysis (of the residual materials after crystallization of the target alditol) to produce glycols. The residual materials from the recovery of the target alditol include non-target alditols (e.g., e.g., mixtures in variable ratios of arabitol, xylitol, sorbitol, mannitol, etc.).

In a specific embodiment, a concentrated solution of monomer sugars is provided wherein the major component is xylose, 70% or more of the solids present. If the total solids concentration of this solution is raised to 75%-80% solids, a significant proportion of the xylose present can then be separated by fractional crystallization of

<img file="MX391237B_D0007.tif" />

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Mexican Institute of Industrial Property the solution. Therefore, the crystalline xylose produced is separated from the mother liquor in a filter or centrifuge and then dried and packaged in bags or drums. The xylose can then be converted into xylitol by dissolving in water, hydrogenating with, for example, a Raney nickel catalyst, and further crystallizing.

A variety of biomass feedstock may be useful for the described processes including, by way of example, but not limited to, bagasse (e.g., sugarcane bagasse, sorghum bagasse, or sugar beet pulp), corn cobs, corn husks, corn husk pericarp, corn stover, grain straw (e.g., alfalfa, barley, oats, rice, or wheat), grasses, hardwoods (e.g., e.g., birch, poplar, alder, eucalyptus and the like), plant leaves, plant stems, softwoods (e.g., cedar, hemlock, pine or spruce), sulfite pulp liquor, algal polysaccharide xylans or combinations thereof.

In one embodiment of this process, the biomass is not a genetically modified organism (GMO) or is derived from a genetically modified species, i.e., the biomass is non-GMO or GMO-free. In a specific embodiment, the feedstock to obtain C5-rich sugar content (e.g., 60–80%) is non-GMO sugarcane bagasse, wheat straw, poplar, hybrid poplar, alder, or a combination thereof.

By way of example, but not limited to, the following industrially useful compositions (individually and in combination) can be recovered from mixed C5/C6 monomer sugar streams by various embodiments described herein shown in Table 1A.

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Table 1A

<td>Formic acid</td><td>Arabinitol</td>

<td>Methanol</td><td>Furfural</td>

<td>Carbon monoxide</td><td>Glutamic acid</td>

<td>Acetaldehyde</td><td>Glutaric acid</td>

<td>Acetic acid and anhydride</td><td>Itaconic acid</td>

<td>Ethanol</td><td>Levulinic acid</td>

<td>Glycine</td><td>Proline</td>

<td>Oxalic acid</td><td>Xylitol</td>

<td>Ethylene glycol</td><td>Xylonic acid</td>

<td>Ethylene oxide</td><td>Aconitic acid</td>

<td>Alanine</td><td>Adipic acid</td>

<td>Glycerol</td><td>Ascorbic acid</td>

<td>3-Hydroxypropionic acid</td><td>Citric acid</td>

<td>Lactic acid</td><td>Fructose</td>

<td>Malonic acid</td><td>2,5-Furan-dicarboxylic acid</td>

<td>Serina</td><td>Glucaric acid</td>

<td>Propionic acid</td><td>Gluconic acid</td>

<td>Acetone</td><td>Kojic and koremic acid</td>

<td>Acetoin</td><td>Lysine</td>

<img file="MX391237B_D0008.tif" />

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MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY

<td>Aspartic acid Butanol Fumaric acid Hydroxybutyrolactone Malic acid Succinic acid Threonine</td><td>Sorbitol</td>

MX/a/2018/009634

Hydrogenation

A C5/C6 monomer sugar stream can be used directly as a hydrogenation feed, where the hydrogenation process converts the monomers to alditols to result in a mixed C5/C6 alditol stream. Alternatively, the C5/C6 monomer sugar stream can be concentrated to increase the total solids content prior to hydrogenation. Such concentration processes are described herein. Furthermore, ethanol, methanol, isopropanol, n-propanol, and the like can be used in the hydrogenation process, either as individual or as mixtures of cosolvent(s). The hydrogenation process can be a batch process, a continuous process, or a combination of these.

Illustrative hydrogenation catalysts include those suitable for high pH (9 and above), high temperature, and aqueous conditions. Such catalysts include transition metal catalysts, such as nickel catalysts supported on zirconium, titanium, or other heavy metal oxide substrates; sponge metal nickel catalyst; or the like. In one embodiment, the catalyst comprises a combination of a zirconium compound and polyacid/promoter material, forming a zirconium promoter precursor having a molar ratio between 2:1 and 20:1; and the polyacid/promoter material may be a polyacid comprising the oxide or acid form of chromium, molybdenum, tungsten, or a combination thereof. In another embodiment, the catalyst comprises nickel, a promoter selected from bismuth, silver, tin, antimony, gold, lead, phosphate, cerium, lanthanum, manganese, or a combination thereof, and a support selected from zirconia or carbon. In one embodiment, the hydrogenation process is carried out using a nickel-based catalyst with a substrate of zirconium oxide, titanium dioxide, aluminum oxide, silicon oxide, chromium oxide, or a combination thereof.

In one embodiment, the catalyst comprises a support comprising zirconium oxide promoted by a polyacid material or promoter, wherein the support is impregnated with a catalytically active metal, such as Group 4 metals (Group IVA), Group 10 metals (Group VIII), Group 11 metals (Group IB), or a combination thereof.

In one embodiment, the hydrogenation process involves a continuous downward flow trickle bed reactor involving three combined phases of solid (hydrogenation catalyst), liquid (mixed C5/C6 monomer sugar stream of about 20 to

<img file="MX391237B_D0009.tif" />

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MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY approximately 30% w/w total solids content, specifically, from approximately 22% to approximately 25% w/w total solids content) and gas (hydrogen). The process further uses a hydrogen pressure of about 4137 to about 13,790 kPa (about 600 to about 2000 psig); a temperature of about 100 to about 160°C, specifically, about 140 to about 160°C; a residence time of about 20 to about 40 minutes; and an initial pH of about 9 to about 12, specifically, about 10 to about 11, to achieve about 99% stoichiometric conversion of monomer sugars to alditols.

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In one embodiment, the hydrogenation process comprises a feed stream of about 20% to about 25% monomer sugar on a dry weight basis wherein the C5 sugars, xylose and arabinose, are present at about 80% and the C6 sugars, glucose and fructose, are present at levels of about 20%; hydrogen gas at about 4 to about 6 times stoichiometric; an initial pH of about 8.0 to about 11.0, specifically, about 9.0 to about 10.0; a temperature of about 120 to about 140°C; a hydrogen pressure of about 8274 to about 13,790 kPa (about 1200 to about 2000 psig), specifically, about 12,411 kPa (about 1800 psig); and a liquid hourly space velocity (LHSV) of about 0.4 to 3.0, specifically, about 1.0-1.5. In this embodiment, the hydrogenation catalyst may be a nickel-based transition metal catalyst (20-40% nickel) in a zirconium and/or titanium substrate support matrix or a Raney nickel (20-60% nickel with copper promoter) based dissolved aluminum matrix catalyst formulated for a fixed trickle bed reactor. Within the Raney nickel embodiment, an alkaline hydroxide promoter, such as sodium hydroxide or potassium hydroxide, may be used to maintain the pH in the range of 8.0 to 10.0.

The conversion of the C5/C6 monomer sugars to the corresponding C5/C6 alditols in the hydrogenation process is at least 95%, specifically, at least 97%, and more specifically, about 100%.

An optional two-stage hydrogenation can be used if the stoichiometric conversion is less than 95%. For example, an optional second-stage continuous reactor can be used, where a stage one reactor achieves a 90-95% conversion of monomer sugars to alditols, and a stage two reactor completes the 95-100% conversion to alditols. A two-stage reactor can be operated at a higher LHSV (liquid hourly space velocity).

<img file="MX391237B_D0010.tif" />

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MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY

Known hydrogenation equipment and techniques can be used to carry out the hydrogenation process. In one embodiment, the equipment is a continuous fixed trickle bed reactor having a cylindrical column length:diameter ratio of approximately 10:2, specifically, a downward-co-current fixed trickle bed reactor in which the hydrogen feed and liquid flow downward, and the liquid flows out from the bottom. The reactor can be adjusted to allow for in-situ backwashing and regeneration. The hydrogen pressure can be from about 4137 to about 13,790 kPa (about 600 to about 2000 psig), specifically, from about 12,411 kPa to 13,790 kPa (about 1800 psig to 2000 psig).

The hydrogenation feed stream or product feed stream may have a total solids content of about 20 to about 27% w/w, specifically, about 22 to about 25% w/w. In addition, the pH of the hydrogenation feed stream may be about 8.0 to about 11.0, specifically, about 9 to about 10. Sodium hydroxide can be used as a pH adjusting alkali, although other alkalis, such as potassium calcium or lithium hydroxide/oxides, can also be used.

If the desired feed concentration is required to be achieved for the hydrogenation reaction feed, the mixed C5/C6 monomer sugar stream can be concentrated to increase the total solids content by removing water. In one embodiment, the mixed C5/C6 monomer sugar stream may be concentrated by using a membrane to allow the passage of water while the mixed C5/C6 monomer sugar stream observes an increase in composition concentration. A suitable exemplary membrane may be a 40-5000 Dalton membrane.

In one embodiment, the hydrogenation is carried out in a purified mixed C5/C6 sugar stream comprising about 20 to about 25% w/w total sugars in water, a pH of about 11, a liquid hourly space velocity (LHSV) of about 1.0, a hydrogen pressure of about 13,790 kPa (about 2000 psig), about 3 to about 6 times stoichiometric hydrogen, and a temperature of about 140°C. and has 99% or more C5/C6 monomer sugar for alditol conversion.

In yet another embodiment, a mixed C5/C6 alditol stream from the hydrogenation process comprises about 65% C5 alditols and about 35% C6 alditols. Furthermore, a mixed C5/C6 alditol stream comprises about 50% xylitol, 15% arabinatol, 25% sorbitol, and about 10% mannitol. In another embodiment, a mixed C5/C6 alditol stream comprises at least 50% xylitol, less than or equal to 15% arabinatol,

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<img file="MX391237B_D0011.tif" />

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MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY less than or equal to 25% sorbitol, and less than or equal to 10% mannitol.

In one embodiment, when the hydrogenation process moves below a 90% conversion of C5/C6 monomer sugars to alditols, the process further comprises: a regeneration cycle wherein a purified mixed C5/C6 monomer sugar feed stream is sent to a partially deactivated nickel substrate catalyst sacrificial reactor prior to direct hydrogenation to reduce sulfur poisoning and reactor fouling followed by stepwise water, caustic soda, and ethanol washing of the catalyst to remove fouling agents followed by hydrogen drying and reduction activation. Fouling includes one, several, or all of the following - saccharification (light burning), scorching, carbonization and/or caramelization of sugars, sulfur poisoning, incapacitation of catalytic reaction sites by impurities or intermediates, and polymerization of sugars resulting in the hydrogenation catalyst becoming physically compromised and plugged.

In one embodiment, hydrogenation production occurs with a catalyst life exceeding 4,000 total hours and with a suitable run time of about 1,000 to about 1,800 hours before catalyst regeneration is performed. Catalyst regeneration may last from about 16 to about 36 hours, or specifically, 24 hours.

In one embodiment, a purified mixed C5/C6 monomer sugar stream comprises C5/C6 monomer sugar, specifically, about 25 to about 50% ethanol and, specifically, about 25 to about 50% water. The ethanol and water, along with pH and temperature, enhance the solubility of the organic polymer impurity and thus reduce downtime.

In one embodiment, a predetermined C5/C6 monomer sugar feedstock prior to hydrogenation may be augmented by, for example, the addition of a more highly concentrated aldose stream. For example, xylose may be crystallized or concentrated separately from other C5/C6 streams, and the concentrated C5 fraction added to a base C5/C6 monomer sugar fraction that shifts the levels of the higher C5s, such as xylose or arabinose. In this way, the target aldoses can be concentrated to produce the desired mixtures for hydrogenation and the subsequent recovery of alditol and glycol downstream. Generally, the higher the concentration of target alditol in the subsequent hydrogenation stream, the higher the yield of purified target alditol. If the concentration of the target alditol in the subsequent hydrogenation stream is too low, e.g. below 25% w/w, then very little or no target alditol may be extracted. The concentration of the target alditol in the subsequent hydrogenation stream can be increased, e.g. by

MX/a/2018/009634

<img file="MX391237B_D0012.tif" />

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Mexican Institute of Industrial Property addition of a feedstock high in aldose that is converted into the target alditol during hydrogenation. The concentration of the target alditol can be greater than 25%, specifically greater than 60%, and more specifically greater than 90% in the subsequent hydrogenation stream.

Figure 2 is an illustrative process flow diagram for the separation and crystallization step (40) including target alditol extraction (10), enhanced alditol extraction (11), further alditol extraction (12), and alditol equilibrium (13).

MX/a/2018/009634

Extraction of target alditol

The hydrogenation product feed stream, which may be a mixed C5/C6 alditol stream, is processed to isolate the target alditols or alditol mixtures. The isolation products may be individual alditols (e.g., sorbitol or xylitol) or alditol mixtures (e.g., defined sorbitol and xylitol ratios for confectionery mixes or cough syrup). For example, xylitol extraction can be achieved from an aqueous mixture of mixed alditols (xylitol, sorbitol, and possible alditol isomers, arabitol, and mannitol) via single-step crystallization or stepwise by sequential removal of water (e.g., by evaporative concentration at elevated temperature) and subsequent temperature decrease to induce crystallization. C5/C6 alditol extraction can be adapted to various feedstocks with varying C5/C6 alditol ratios.

If water and cosolvents (e.g., ethanol) are used, they can be removed by processes including multiple effect evaporation, steam distillation, multiple vapor recompression evaporators, reverse osmosis, or a combination of these.

In one embodiment, the water removal is performed at a temperature of about 30 to about 120 °C under vacuum, specifically, about 70 to about 110 °C under reduced pressure, and more specifically, about 80 to about 100 °C under reduced pressure, for example, less than 30 kPa (200 mbar), specifically, about 10 to about 18 kPa (about 100 to about 180 mbar), and more specifically, from about 14 to about 17 kPa (from about 140 to about 165 mbar).

The concentrated feed stream may have a total dissolved solids content of about 40% to about 90% w/w, specifically, about 60% to about 85% w/w, and more specifically, about 75% to about 85% w/w.

Enhanced alditol extraction

Specific alditols, such as xylitol, arabitol or sorbitol, or mixtures of alditol

<img file="MX391237B_D0013.tif" />

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INSTITUTO MEXICANO DE LA PROPIEDAD INDUSTRIAL can be isolated from an aqueous mixture of mixed alditols (such as xylitol, sorbitol, arabitol and mannitol) through generally recognized as safe (GRAS) solvent precipitation or crystallization, industrial chromatography including simulated moving bed (SMB) or a combination of these, specifically, GRAS solvent precipitation or crystallization, to isolate the target alditol or target alditol mixture. Crystalline forms of the target alditol can be sized to specification, while liquid formulations of the target alditol mixtures can also be manufactured to specification.

MX/a/2018/009634

Suitable solvents include lower alcohols (e.g., ethanol, isopropanol, etc.) and mixtures of these with water. An illustrative GRAS solvent includes ethanol.

Before crystallization or precipitation, the alditol solution (e.g., xylitol) may be treated with activated carbon to remove impurities that may interfere with alditol crystallization. Suitable activated carbon includes powdered activated carbon, granular activated carbon, and the like, or a combination of these. Other processes for removing crystallization inhibitors include one or more of the following, optionally in combination with activated carbon treatment: ion exchange, membrane filtration, solvent extraction. Other conditioning steps include stepwise electrodialysis, strong acid ion exchange resin treatment, and chemical precipitation of calcium sulfate, and optionally further comprise recovery of spent inorganic material. A determination of whether or not the mixed C5/C6 alditol solution or alditol stream requires preconditioning (purification) prior to crystallization, and to what extent, can be made by one skilled in the art without undue experimentation. For example, analytical techniques known in the art can be used to determine the type and amount of components in the mixed C5/C6 alditol solution or alditol stream so that appropriate purification technique(s) can be used.

The crystallization process can be carried out using a continuous or batch process. Crystallization equipment and techniques known in the art can be used to crystallize the target alditol. Suitable crystallization equipment and solid-liquid separation equipment include tank crystallizers (horizontal, vertical, cooling crystallizers, evaporative crystallizers), centrifuges, and the like.

After achieving a desirable solids weight during the crystallization process, the target alditol solids can be isolated using techniques known in the art, such as filtration, centrifugation, a combination of these, and the like. The solids can be washed, dried, sized, or a combination of these.

The mother liquor from the crystallization process can be further processed for additional target alditol cultures or other alditol or used as a feedstock (waste mixed C5/C6 alditol stream) for the production of glycols via hydrogenolysis.

<img file="MX391237B_D0014.tif" />

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MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY

In one embodiment, crystallization of a concentrated aqueous feed comprising predominantly xylitol (e.g., e.g., >75% of total alditols) and low levels of other alditols, such as galactitol, lixitol, and sorbitol, can be accomplished by cooling a concentrated aqueous feed having a total dissolved solids content of about 50 to about 85% w/w, specifically, about 65 to about 85% w/w, and more specifically, about 70 to about 85% w/w, from about 60 to about 100 °C to a temperature of about -10 to about 40 °C, specifically, from about 20 to about 35 °C, after which a seed of the target alditol may optionally be added.

An antisolvent, such as ethanol, isopropanol, or another GRAS solvent, may optionally be added to the concentrated aqueous feed while maintaining the temperature below the flash point of the antisolvent, for example, below about 40°C, specifically, below about 35°C for ethanol. Optionally, a seed of the target alditol may be added to induce and/or promote crystallization.

The concentrated aqueous feed may be cooled to a target temperature below ambient temperature, specifically, from about -10 to about 20°C and, more specifically, from about -5 to about 5°C. After crystallization of the target alditol, a slurry having a solids content of about 15 to about 45%, specifically, about 20 to about 40% solids, may be fed to a solids recovery device, such as a centrifuge, to separate the solid from the mother liquor. By this illustrative method, high purity aditol (>98%) can be achieved, although cooling can be adjusted according to the desired yield compared to solid product purity.

In one embodiment, crystallizing xylitol as the target alditol in pure form from mixed alditol streams may involve establishing and delivering threshold concentration levels of xylitol (minimum concentrations) and other alditols (maximum concentrations) to enable recovery of xylitol in efficient yield and with purity suitable for premium applications. The threshold levels depend on the water:antisolvent ratio present in the system.

The concentration of the component in the crystallization liquor is calculated as % of

MX/a/2018/009634 total solids multiplied by the proportional concentration of alditol in the total solids.

The threshold concentration can be affected by the following factors;

Solubility limit of the component in the solvent at the temperature used

Impact of the antisolvent (and its concentration)

<img file="MX391237B_D0015.tif" />

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MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY

Impact on the solubility of the component by other solutes, which can depress or enhance its solubility

The tendency of another component to interfere with the crystallization of the desired crystalline component - e.g., by incorporating itself into the crystal lattice of the desired component.

Examples of threshold limits have been determined to be in the following regions, i.e., maximum levels of each alditol in the crystallization liquor that still allow efficient purification of xylitol, when xylitol is the target alditol:

Generally, the presence of high concentrations of sorbitol and mannitol has a significant effect on the physical behavior of xylitol crystallization. High levels of sorbitol and mannitol result in co-crystallization of sorbitol and/or mannitol with xylitol, which can inhibit the filtration rate of the resulting mixture.

For xylitol, at least 20% w/w, more specifically, greater than about 42% w/w xylitol concentration based on total solids weight is required to produce xylitol, more specifically, greater than 60% w/w in solution to provide improved yield; (e.g., 80% total solids in a solution with a minimum of 80% w/w xylitol of the total solids). Furthermore, within this xylitol modality, the arabinitol concentration was less than 10% w/w of total solids, otherwise, the xylitol purification is impaired. Furthermore, within this xylitol modality, mannitol has a low level of solubility, therefore, a threshold concentration level of 10% w/w is set. At a level greater than 10% w/w mannitol based on total solids, undesirable co-crystallization of mannitol with xylitol is observed. In one embodiment, a mannitol content of less than 4% w/w of the crystallization liquor was found to allow for successful purification of xylitol. Furthermore, within this embodiment of xylitol, when sorbitol is present at concentrations greater than or equal to 15% w/w of total solids, the crystallization rate and filtration rates are reduced.

Within this embodiment with respect to the xylitol threshold, xylitol represents a minimum of 60% of total solids, more specifically, greater than 80% of total solids, and after evaporative concentration to a minimum of 75% w/w total solids in solution at about 60 to about 70°C, the actual xylitol concentration is, specifically, greater than 60%. If an anti-solvent is used in this embodiment, the actual xylitol concentration is greater than 50%. The maximum threshold levels of other components depend on the water:antisolvent ratio present in the system. Arabitol is present at less than 10% in a 50:50 water:ethanol system, as higher concentrations of this alditol have a negative impact on the kinetics and purity of xylitol crystallization. Mannitol is present at less than

MX/a/2018/009634

IMPI» |

MEXICAN INSTITUTE^F OF PROPERTY H or

INDUSTRIAL

20S?

4% due to co-crystallization with xylitol. Exact threshold levels may vary slightlyθ ω based on the overall liquor composition and the amount of antisolvent.

The xylitol crystallization solution may have a total dissolved solids content high enough for controlled xylitol crystallization, but low enough to prevent rapid bulk crystallization. In various embodiments, the crystallization solution may have a total dissolved solids content of about 40% to about 80% w/w, specifically, about 60% to about 85% w/w, and more specifically, about 70% to about 75% w/w.

In one embodiment for crystallizing xylitol, the xylitol content as a % of total solids in the crystallization solution is 50% or more, specifically, 55% or more, more specifically, 60% or more. Furthermore, within this embodiment, the amount of arabitol as a % of total solids in the crystallization solution is less than or equal to 10%, specifically, less than or equal to 5%, and more specifically, less than or equal to 2%. Alternatively, within this embodiment, the amount of mannitol as a % of total solids of the crystallization solution is less than or equal to 10%, specifically, less than or equal to 5%, and more specifically, less than or equal to 2%. Alternatively, within this embodiment, the amount of arabitol as a % of total solids in the crystallization solution is less than or equal to 10%, specifically, less than or equal to 5%, and more specifically, less than or equal to 2%; and the amount of mannitol as a % of total solids in the crystallization solution is less than or equal to 10%, specifically, less than or equal to 5%, and more specifically, less than or equal to 2%. In this embodiment, the solution does not include an antisolvent. In another embodiment, the solution may comprise a combination of water and an antisolvent, such as ethanol, specifically, approximately a 95:5 ratio of water:ethanol to a 5:95 ratio of water:ethanol, more specifically, approximately a 95:5 ratio of water:ethanol to a 5:95 ratio of water:ethanol.

In one embodiment for crystallizing xylitol, the xylitol content as a % of total solids in the crystallization solution is 50% or more, specifically, 55% or more, more specifically, 60% or more; and the amount of sorbitol as a % of total solids in the crystallization solution is less than or equal to 15%, specifically, less than or equal to 10%, and more specifically, less than or equal to 5%. In this embodiment, the solution does not include an antisolvent. In another embodiment, the solution may comprise a combination of water and ethanol, specifically, about a 95:5 ratio of water:ethanol, to a 0:1 ratio of water:ethanol.

In an alternative embodiment, chromatography can be used to separate alditols, thereby eliminating the need to control threshold levels in the alditol crystallization step.

<img file="MX391237B_D0016.tif" />

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MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY

In one embodiment, a mixed C5/C6 alditol stream is at least partially separated by chromatography into a C5 alditol fraction and a C6 alditol fraction.

In one embodiment, a mixed C5/C6 alditol stream is separated by chromatography into a C5 alditol fraction and a C6 alditol fraction; and a target alditol is crystallized from the C5 alditol fraction using ethanol and water. The mother liquor containing residual alditols can be directed to the hydrogenolysis process for conversion to glycols.

In one embodiment, isolating a target alditol from a mixed C5/C6 alditol stream via crystallization includes removing ethanol, water, or a combination thereof from the mixed C5/C6 alditol stream.

In one embodiment, a target alditol is a C5 alditol or a C6 alditol.

In one embodiment, a target alditol is xylitol. In another embodiment, a target alditol is sorbitol or arabitol.

In one embodiment, the xylitol obtained from the crystallization process contains from about 90 to about 100% xylitol, specifically, from about 96 to about 99.99% xylitol, and more specifically, from about 98.5 to about 99.99% xylitol. In one embodiment, the xylitol obtained from the crystallization process contains less than 1% of other alditols.

MX/a/2018/009634

Another alditol extraction

After the target alditol or alditol mixture has been extracted from the alditol stream, the remaining mixed aqueous alditol feed containing a fraction of the target alditol, such as xylitol, can be processed to fractionate sorbitol, arabitol, mannitol, or combinations thereof, via industrial chromatography. The target alditol products from this step can be in liquid or crystalline form. Optionally, a target alditol, typically about 85% to about 95% pure, may be concentrated and crystallized in a second extraction.

Alditol balance

After the removal of a majority of the target alditols (e.g., xylitol or sorbitol) from the alditol stream, the remaining C5/C6 alditol balance can be shifted to prepare the remaining alditols for hydrogenolysis and thus the specific glycol product slates. For example, high C6 would tend to favor propylene glycol and butanediol isomers as hydrogenolysis products, while C5 alditols would favor ethylene glycol and glycerin as a hydrogenolysis product.

Processes such as chromatography, precipitation and the like may produce

<img file="MX391237B_D0017.tif" />

IMPI2

Mexican Institute of Industrial Property separated fractions rich in C5 alditols and C6 alditols. Hydrogenolysis of the enriched fractions will yield the target glycol products.

Figure 3 is a process flow diagram for the hydrogenolysis and separation stage (50) including hydrogenolysis (14) and glycol separations (15).

MX/a/2018/009634

Hydrogenolysis

Residual alditols and alditol mixtures can be converted through hydrogenolysis to target hydrogenolysis products, including glycols and glycerol. Hydrogenolysis can be performed at high temperature and pressure in the presence of hydrogen.

Illustrative target glycols to be formed include: ethylene glycol, propylene glycol, 1-3 propane diol, butanol, butanediol isomers (1,2-butanediol; 1,4-butanediol; 1,3-butanediol; and 2,3-butanediol), and mixtures thereof. Glycerin may be another target hydrogenolysis product.

Illustrative hydrogenolysis catalysts include transition metal catalysts, noble metal catalysts, and metal catalysts in a support matrix formulated for aqueous conditions and high pH (above 9). The illustrative catalyst described above for the hydrogenation process can be used in the hydrogenolysis process. In one embodiment, the hydrogenolysis catalyst is a substrate support matrix based on nickel (20-40% nickel) or zirconia or titanium dioxide.

In one embodiment, the hydrogenolysis is performed at a temperature of about 240°C; a pressure of about 6895 to about 13,790 kPa (about 1000 to about 2000 psig); a pH of about 10 or greater; and a liquid hourly space velocity (LHSV) of about 0.5 to about 3.0.

In one embodiment, the hydrogenolysis is performed at a temperature of about 210 to about 250°C, specifically, about 220 to about 240°C; a pressure of about 6895 to about 13,790 kPa (about 1000 to about 2000 psig), specifically, about 8274 to about 12,411 kPa (about 1200 to about 1800 psig); a pH of about 9.0 to about 11.0, specifically, about 10.0; and a liquid hourly space velocity (LHSV) of about 0.5 to about 2.0, specifically, about 0.8 to about 1.5, and more specifically, about 1.0. Furthermore, within this embodiment, a feed of about 20 to about 25% mixed alditols (e.g., C5/C6 alditols) on a dry weight water basis is used. The amount of hydrogen can be about 4 to about 6 times stoichiometric. In addition, within this embodiment, a promoter is used,

<img file="MX391237B_D0018.tif" />

IMPI»

Mexican Institute of Industrial Property, such as sodium hydroxide. The conversion of C5/C6 alditol to mixed glycols can be greater than 70%, specifically, greater than 80%.

In one embodiment, the process comprises continuously hydrogenolyzing a waste mixed C5/C6 alditol stream having about 20 to about 25% w/w total solids content of alditol in water, a pH of about 11, an LHSV of about 1.0, a hydrogen pressure of about 13,790 kPa (about 2000 psig) and a temperature of about 240°C in the presence of a nickel-based catalyst to form the mixed glycol stream comprising propylene glycol, ethylene glycol, glycerin, butanediol isomers, or a combination thereof.

In one embodiment, the hydrogenolysis process produces a mixed glycol stream comprising propylene glycol (about 15% to about 25%), ethylene glycol (about 20% to about 30%), glycerin (about 10% to about 30%), and butanediol isomers (about 10% to about 20%).

The hydrogenolysis feed and the resulting mixed glycol stream can comprise ethanol and water. Here, ethanol can be added as a cosolvent, which improves hydrogen solubility and reduces energy requirements. Alcohols have a lower heat of vaporization, and the use of a low-boiling ethanol/water azeotrope allows for further reductions in energy costs.

In one embodiment, a residual mixed C5/C6 alditol stream used as a hydrogenolysis feed for the hydrogenolysis process may comprise alditol, about 25 to about 50% ethanol, and about 25 to about 50% water.

In one embodiment, the hydrogenolysis process is performed by using a nickel-based catalyst with a substrate that includes zirconium oxide, titanium dioxide, or a combination thereof.

In one embodiment, when the hydrogenolysis process moves below a 90% conversion of C5/C6 alditols to glycols, the process further comprises a regeneration cycle including stepwise washing of hot water, caustic soda and ethanol of the catalyst to remove fouling agents followed by hydrogen drying and reduction activation.

MX/a/2018/009634

Glycol separations

The product stream from the hydrogenolysis process containing a mixture of glycols and glycerin can be separated into target hydrogenolysis products which include products

<img file="MX391237B_D0019.tif" />

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Mexican Institute of Industrial Property of target glycol. Illustrative separation processes include a combination of classical distillation, extractive processes, and extractive and/or azeotropic distillation to isolate and purify near-boiling glycols. Target hydrogenolysis products include ethylene glycol, propylene glycol, glycerin, and butanediol isomers.

Propylene glycol can be separated into industrial-grade and United States Pharmacopeia (USP)-grade propylene glycol by azeotropic distillation. Ethylene glycol can be separated into industrial-grade and polyethylene terephthalate (PET) resin-grade ethylene glycol by azeotropic distillation. Butanediols can be concentrated and purified into individual 1,2-, 2,3-, and 1,3-butanediols, respectively, for industrial use. Glycerin can be extracted and/or recycled into the mixed alditol hydrotreating feedstock prior to hydrogenolysis and can be converted to propylene glycol and ethylene glycol.

In one embodiment, a process for generating C5/C6 alditols and C2-C4 glycols from biomass-derived mixed C5/C6 sugar streams comprises deconstructing and hydrolyzing a biomass source under alkaline, acidic, enzymatic, or acidic and enzymatic conditions to form a biomass hydrolysate stream comprising one or more of a sugar monomer, oligomeric sugar, hemicellulose, cellulose, solubilized lignin, and impurities, such as non-sugar organic compounds. ash and inorganic contaminants; conditioning the biomass hydrolysate stream to remove lignin, non-sugar organic compounds, and inorganic contaminants to form a purified mixed C5/C6 sugar stream; acid hydrolyzing the purified mixed C5/C6 sugar stream to form a mixed C5/C6 monomer sugar stream; hydrogenating the mixed C5/C6 monomer sugar stream to form a mixed C5/C6 alditol stream; isolating a target alditol from the mixed C5/C6 alditol stream via crystallization to leave a residual mixed C5/C6 alditol stream; hydrogenolysis of the residual mixed C5/C6 alditol stream to form a mixed glycol stream; and isolating a target glycol. In this embodiment, the deconstruction and hydrolyzation of a biomass source is carried out under alkaline conditions. In this embodiment, the biomass is derived from wheat straw. In this embodiment, conditioning is achieved through the use of progressive membranes and selected carbon treatment. In this embodiment, hydrogenation is carried out under fixed-bed nickel catalysis; and hydrogenolysis is performed under a nickel catalyst. In one embodiment, the target alditol is xylitol and the target glycol is propylene glycol. The inorganic contaminants removed are chlorides, sulfates, phosphates, or a combination of these.

Xylitol, sorbitol, other alditols, and certain alditol mixtures (e.g., defined sorbitol-xylitol ratios) prepared by the processes described can be used in a wide variety of applications including use as a sweetener in food products and oral care products, as a component in pharmaceuticals, and for

MX/a/2018/009634

<img file="MX391237B_D0020.tif" />

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Mexican Institute of Industrial Property industrial applications. As a sweetener, it can be used alone or in combination with other sweeteners in confectionery products, chewing gum, sauces, beverages, and similar products. Since xylitol is non-cariogenic and does not affect insulin levels in people with diabetes, it has particular use in food products. Furthermore, due to its very high negative heat of solution, consumption of xylitol produces a cooling sensation in the consumer's mouth. Because of this effect, xylitol is commonly used in chewing gum to provide a cooling sensation. In pharmaceutical products, it can be used as a sweetener, an excipient, and

MX/a/2018/009634 similar. Oral care products may include toothpaste, tooth powder, mouthwash, breath films, and the like.

In addition, alditols have a use in various industrial applications including the preparation of resins and surfactants, use as a plasticizer for a variety of polymers and the like.

Target glycols prepared by the described processes include propylene glycol for general industrial use and for cosmetic and food applications; target ethylene glycol for resin-grade quality for polyethylene terephthalate (PET) containers; and butanediol isomers for value-added pharmaceutical resins and precursors.

Pulp from biomass deconstruction processes can be used to produce vulcanized fiber, specialty paper, and/or other pulp applications that replace conventional hardwood and softwood pulps.

Isolated lignin fractions can be used for specific industrial uses including lignosulfonates, resin production, and the like, or they can be used as a low-sulfur fuel.

In one embodiment, a process comprises deconstructing poplar, bagasse, or a combination thereof by using acidic conditions to form a mixed C5/C6 sugar stream; selecting a target alditol or a mixture of target alditols; conditioning the mixed C5/C6 sugar stream to remove lignin, organic impurities, and inorganic impurities; hydrolyzing the mixed C5/C6 sugar stream to form a mixed C5/C6 monomer sugar stream; continuously hydrogenating a mixed C5/C6 monomer sugar stream to form a mixed C5/C6 alditol stream; isolating the target alditol or target alditol mixture from the mixed C5/C6 alditol stream to leave a residual mixed C5/C6 alditol stream; continuously hydrogenating the residual mixed C5/C6 alditol stream to form a mixed C2-C4 glycol stream; and isolating a target glycol or target glycol mixture from the mixed C2-C4 glycol stream; wherein at least 10% of the overall target product yield is target alditol/target alditol mixture or target glycol/target glycol mixture; wherein the target alditol is xylitol and the target glycol is propylene glycol, or a combination thereof; and wherein the xylitol is isolated by crystallization, optionally, with

<img file="MX391237B_D0021.tif" />

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MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY ethanol or isopropanol antisolvent.

In another embodiment, a process comprises continuously hydrogenating a mixed C5/C6 monomer sugar stream to form a mixed C5/C6 aldol stream; isolating xylitol from the mixed C5/C6 aldol stream to leave a residual mixed C5/C6 aldol stream; continuously hydrogenolyzing the residual mixed C5/C6 aldol stream to form a C2-C4 glycol stream.

MX/a/2018/009634 mixed; isolating a target glycol or target glycol mixture from the mixed C2-C4 glycol stream; wherein at least 10% of the overall target product yield is xylitol or target glycol or target glycol mixture.

In one embodiment, a process comprises isolating a target C5/C6 monomer sugar or target C5/C6 monomer sugar mixture from a mixed C5/C6 monomer sugar stream to form a residual mixed C5/C6 monomer sugar stream; continuously hydrogenolyzing the residual mixed C5/C6 monomer sugar stream to form a mixed C2-C4 glycol stream; and isolating a target glycol or target glycol mixture from the mixed C2-C4 glycol stream; wherein at least 10% of the overall target product yield is target C5/C6 monomer sugar/target C5/C6 monomer sugar mixture or target glycol/target glycol mixture. Within this embodiment, the target C5/C6 monomer sugar may be cellulose.

In another embodiment, a process comprises selecting at least two target products based on a biomass feedstock source; converting the biomass feedstock into the at least two target products, wherein at least 10% of the overall target product yield is one of the at least two target products; and if overall target product performance needs to be maintained, modifying the selection of the at least two target products if there is a change in the biomass feedstock source; wherein one of the at least two target products is a target C2-C4 glycol or a target C2-C4 glycol mixture; and wherein the remainder of the at least two target products is a target [C5/C6] alditol, a target [C5/C6] alditol mixture, a target [C5/C6] monomer sugar, a target [C5/C6] monomer sugar mixture, or a combination thereof; and wherein an operational treatment is performed no more than two or three times on any single feedstock stream, wherein the operational treatment is a hydrogenation, a hydrogenolysis, a biomass deconstruction process, or an isolation process; and the feedstock stream is a biomass feedstock stream, a hydrolysate stream, a monomer sugar stream, an aldol stream, a glycol stream, or a combination thereof. Within this modality, at least one stage of the process can be carried out continuously. Furthermore, within this modality, the process can be carried out at a single production site or on a single production line.

<img file="MX391237B_D0022.tif" />

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In one embodiment, a process comprises selecting at least two target products based on a source of a hydrolysate stream; converting the hydrolysate stream into the at least two target products;

MX/a/2018/009634 at least two target products, where at least 10% of the overall target product yield is one of the at least two target products; and if the overall target product yield needs to be maintained, modifying the selection of the at least two target products if there is a change in the source of the hydrolysate stream; where one of the at least two target products is a target C2-C4 glycol or a target C2-C4 glycol mixture; and wherein the remainder of the at least two target products is a target [C5/C6] alditol, a target [C5/C6] alditol mixture, a target [C5/C6] monomer sugar, a target [C5/C6] monomer sugar mixture, or a combination thereof; and wherein an operational treatment is performed no more than two or three times in any single feedstock stream, wherein the operational treatment is a hydrogenation, a hydrogenolysis, or an isolation process; and the feedstock stream is the hydrolysate stream, a monomer sugar stream, an alditol stream, a glycol stream, or a combination thereof. Within this embodiment, at least one process step can be performed continuously. Furthermore, within this embodiment, the process can be performed at a single production site or a single production line.

In another embodiment, a process comprises selecting at least two target products based on a source of a mixed monomer sugar stream; converting the mixed monomer sugar stream into the at least two target products, wherein at least 10% of the overall target product yield is one of the at least two target products; and if overall target product performance needs to be maintained, modifying the selection of the at least two target products if there is a change in the source of the mixed monomer sugar stream; wherein one of the at least two target products is a target C2-C4 glycol or a mixture of target C2-C4 glycols; and wherein the remainder of the at least two target products is a target [C5/C6] alditol, a target [C5/C6] alditol mixture, a target [C5/C6] monomer sugar, a target [C5/C6] monomer sugar mixture, or a combination thereof; and wherein an operational treatment is performed no more than two or three times in any single feedstock stream, wherein the operational treatment is a hydrogenation, a hydrogenolysis, or an isolation process; and the feedstock stream is a monomer sugar stream, an alditol stream, a glycol stream, or a combination of these. Within this embodiment, at least one step in the process can be performed continuously. Furthermore, within this embodiment, the process can be carried out at a single production site or a single production line.

The features and benefits are shown in more detail in the following examples, which are provided for illustrative purposes only and should not be construed in any way as

<img file="MX391237B_D0023.tif" />

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MX/a/2018/009634 limitations of the invention.

Examples

Example 1.

Cellulose and small suspended lignin fractions that do not dissolve in the alkaline pulp liquor, as well as high-molecular-weight hemicellulose, can be extracted with the cellulose to increase pulp yield. Pulping operating conditions can reduce the molecular weight of hemicellulose, favoring higher hemicellulose recovery from the liquor and, therefore, higher net C5/C6 sugars. Wheat straw hemicellulose has a typical xylan:glucan ratio of approximately 75:25. Therefore, if all cellulose is removed (C6), then the highest possible yield of C5 sugar (xylose/arabinose) would be 75% xylose/arabinose entirely from the hemicellulose fraction. If all the cellulose in wheat straw were converted to C6 sugars, and in this case the hemicellulose in wheat straw were converted to C5 and C6 sugars, there is a maximum of 2.19 times more C6 sugars than C5. If all the sugars (cellulose and hemicellulose) were converted to monomers, C5 would be a maximum of about 31% of the total sugars in cellulose and hemicellulose. If all C6 cellulose were removed, the maximum C5 sugar concentration in the hemicellulose fraction would only be 75%. Therefore, it is possible to set specific C5 to C6 sugar ratios and target pulping and other pretreatment conditions to a) favor specific sugars and hydrotreating sugars and b) adjust C5 levels through C6 pulp (cellulose) recovery.

Example 2· Hydrogenation of C5/C6 sugars

Xylose and arabinose (C5 sugars) and feed co-load hexose C6 sugars (glucose, galactose, mannose, and fructose) are hydrogenated to a dry weight sugar to water concentration of 20-25% at a pH of 10-12 at 125-150°C and 12,411-13,790 kPa (1800-2000 psig) over a proprietary catalyst series. The liquid hourly space velocity (LHSV) is 0.4-1.5 with a stoichiometric hydrogen surplus of 4-6. The overall conversion is 99% sugars to alditols. Byproducts include unreacted aldoses and possible alternative C5 or C6 alditol isomers. Tables 2A, 2B, and 2C summarize a series of hydrogenations with varying conditions and catalysts that illustrate alditol production conditions.

Co-production of C5 and C6 alditols with target alditols that are fractionated and purified into industrial and/or food grade materials and other non-target alditols that are sent to hydrogenolysis for glycol production. Partial recovery of target alditols, such as

<img file="MX391237B_D0024.tif" />

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IMPI 2

N) GO xylitol or sorbitol and that do not require high-throughput and high-recovery separation scenarios (greater than 75-90% for xylitol or sorbitol, for example) drastically reduces the net costs of alditol separations and even optimizes the total yield of alditol and glycol. Therefore, the coproduction of alditols and glycols facilitates lower costs and higher net yields. Tables

2B and 2C illustrate the basic principles of hydrogenation to take xylose and convert xylose to xylitol by using a sponge metal catalyst with a nickel content of about 50 to about 80%.

MX/a/2018/009634

<img file="MX391237B_D0025.tif" />

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N) GO

Table 2A

Illustrative glucose hydrogenation process conditions and results

<td>Total feed conversion (%)</td><td> 99.4</td><td> 97.8</td><td> 99.9</td><td> 99.1</td>

<td>Sorbitol created (g/D)</td><td> 199.9</td><td> 199.5</td><td> 194.6</td><td> 192.5</td>

<td>Mannitol created (g/i)</td><td> 10.5</td><td> 16.7</td><td> 15.8</td><td> 14.2</td>

<td>Remaining glucose (g/i)</td><td>(N t—1</td><td> 4.7</td><td> 0.3</td><td>OO t—1</td>

<td>Glucose in food (g/D)</td><td> 214.1</td><td> 218.7</td><td> 218.5</td><td> 213.2</td>

<td>Product pH</td><td> 5.0</td><td> 4.6</td><td> 4.9</td><td> 4.6</td>

<td>Feed pH</td><td> 9.9</td><td> 10.0</td><td> 9.9</td><td> 9.6</td>

<td>Average temperature (°C)</td><td> 109</td><td> 112</td><td> 110</td><td>i—1 i—1 i—1</td>

<td>Reactor pressure kPa (psi)</td><td> 8012 (1162)</td><td> 7915 (1148)</td><td> 12,162 (1764)</td><td> 12,107 (1756)</td>

<td>Hydrogen gas flow (g/h)</td><td> 100</td><td> 125</td><td> 100</td><td> 100</td>

<td>LHSV (1/h)</td><td>(N t—1</td><td> 1.4</td><td>O t—1</td><td>(N i—1</td>

<td>Sample ID</td><td>or 00 LD</td><td>J700</td><td>J701</td><td>J743</td>

<td>Total feed conversion (%)</td><td>0Ό0Τ</td><td>0Ό0Τ</td><td>0Ό0Τ</td><td>0Ό0Τ</td><td>0Ό0Τ</td><td> 98.6</td>

<td>Xylitol created (g/D)</td><td> 193.7</td><td> 194.6</td><td> 210.9</td><td> 210.9</td><td> 204.5</td><td> 203.2</td>

<td>Arabitol created (g/D)</td><td> 13.2</td><td> 13.2</td><td> 0.0</td><td> 0.0</td><td> 8.4</td><td> 4.2</td>

<td>Remaining xylose (g/D)</td><td> 0.0</td><td> 0.3</td><td> 0.3</td><td> 0.3</td><td> 0.0</td><td>in</td>

<td>Xylose in feed (g/l)</td><td> 215.8</td><td> 215.0</td><td> 218.4</td><td> 218.4</td><td> 220.9</td><td> 216.9</td>

<td>Product pH</td><td> 4.7</td><td> 4.8</td><td> 4.7</td><td> 4.8</td><td> 9.8</td><td>CN in</td>

<td>Feed pH</td><td> 9.5</td><td> 9.5</td><td> 9.5</td><td> 9.5</td><td> 9.5</td><td>LQ OO</td>

<td>Average temperature (°C)</td><td> 105</td><td> 105</td><td> 100</td><td> 100</td><td>CXl in</td><td>i—1 in</td>

<td>Reactor pressure kPa (psi)</td><td> 12,024 (1744)</td><td> 12,135 (1760)</td><td> 12,266 (1779)</td><td> 12,286 (1782)</td><td> 12,486 (1811)</td><td> 12,417 (1801)</td>

<td>Hydrogen gas flow (g/h)</td><td>oi—1</td><td> 150</td><td> 150</td><td> 150</td><td> 150</td><td>Ln</td>

<td>LHSV (1/h)</td><td> 1.0</td><td> 1.4</td><td>i—1</td><td>i—1</td><td>i—1</td><td>i—1</td>

<td>Sample ID</td><td>J753</td><td>J758</td><td>J771</td><td>J773</td><td>J776</td><td>J798</td>

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<img file="MX391237B_D0026.tif" />

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N) GO

Table 2C

Illustrative process conditions and results of hydrogenation of wheat straw sugar (Source 1)

<td>sisH ! &gt; «&gt; S</td><td> 95.3</td><td>0T6</td><td> 93.4</td><td> 97.9</td>

<td>= 2 ό ai X u</td><td> 141.7</td><td> 184.2</td><td> 183.7</td><td> 82.9</td>

<td>Sorbitol created (g/D)</td><td> 15.0</td><td> 18.6</td><td> 18.6</td><td> 9.5</td>

<td>Arabitol / Created Mannitol (g/D</td><td> 17.3</td><td> 23.9</td><td> 24.2</td><td> 10.9</td>

<td>íü ¿ 8 J3 « s, x ω</td><td> 6.6</td><td> 9.7</td><td> 9.0</td><td> 2.8</td>

<td>íü 1 ω c 8 13 cd 3 id 0</td><td> 4.4</td><td> 6.6</td><td> 6.5</td><td>CX1 r\¡</td>

<td>Squeezing in food (g/D)</td><td> 4.4</td><td> 4.4</td><td> 4.4</td><td> 4.4</td>

<td>Galactose in food (g/D</td><td> 3.0</td><td> 3.0</td><td> 3.0</td><td> 3.0</td>

<td>Arabinose in food (g/D</td><td></td><td></td><td></td><td></td>

<td>Xylose in feed (g/D)</td><td> 200.8</td><td> 200.8</td><td> 200.8</td><td> 200.8</td>

<td>Glucose in food (g/D</td><td> 18.2</td><td> 18.2</td><td> 18.2</td><td> 18.2</td>

<td>Product pH</td><td> 4.8</td><td> 4.8</td><td> 5.0</td><td> 5.4</td>

<td>Feed pH</td><td> 9.0</td><td> 9.0</td><td> 9.0</td><td> 9.0</td>

<td>Average temperature (°C)</td><td>in in</td><td></td><td></td><td> 00 00</td>

<td>Reactor pressure kPa (psi)</td><td> 12,431 (1803)</td><td> 12,390 (1797)</td><td> 12,376 (1795)</td><td> 12,362 (1793)</td>

<td>Hydrogen gas flow (g/h)</td><td>Ln</td><td>Ln</td><td>Ln</td><td>Ln</td>

<td>LHSV (1/h)</td><td> 1.4</td><td> 1.4</td><td> 1.4</td><td> 1.4</td>

<td>Sample ID</td><td>J799</td><td>oo 00</td><td>J801</td><td>J802</td>

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<img file="MX391237B_D0027.tif" />

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MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY

In summary, there are two main products of interest in alditol production (as described above, e.g., sorbitol and xylitol). The primary objective of producing mixed alditols (with or without removed target alditols) is to provide a C5/C6 hydrogenolysis feedstock. Therefore, mixed alditols from hydrogenation can be a source of specific alditols (such as mannitol or arabitol) or alditols for hydrogenolysis to make high-value glycols.

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Example 3· Selective concentration of C5 alditols through unit operations

After hydrogenation of C5/C6 sugars, generally, C5/C6 sugars, regardless of the C5/C6 ratio or the variability of various C5/C6 alditol isomers, will result in a 97–99% conversion of sugar aldoses to corresponding alditols. Alditol drift may slightly alter isomeric compositions, but the overall conversion should be constant and high.

If, for example, xylitol is a target alditol, then several process options would be possible for xylitol concentration and subsequent further purification to a liquid or crystallized product. First, for lower xylitol concentrations, such as xylitol less than 30% of the total C5/C6 alditols, classical and/or recent developments in industrial chromatography, including simulated moving bed (SMB) technology, could be used. Depending on the system configuration, resin types, and elution and recycling loops, the concentration could range from 30% to 50% to 70%. In the other state of the art, chromatographic separation processes currently focus entirely on maximizing the recovery of the target material and concentrating the materials. This dual criterion of high removal rates and high purity of the recovered fractions is burdensome in terms of operations and costs. More equipment, higher recycling rates, high dilutions, etc. are required. Therefore, 20–40% recovery at higher purities is considered acceptable. The goal is to purify and concentrate a fraction of the target alditols, but full recovery is not necessary. The production of glycols downstream after hydrogenolysis serves as a final value-added co-product for the target alditols. Furthermore, by changing the physical properties of non-volatile alditols, which are difficult to separate, to volatile glycols that can be easily separated by distillation, the overall net costs of separating alditols and glycols are lower. Similarly, sorbitol or mannitol (C6 alditols) could be established as the main product alditol.

Table 3 summarizes several alternative resin and SMB system configurations and the resulting xylitol and sorbitol concentrations from the respective alditol mixtures.

<img file="MX391237B_D0028.tif" />

IMPI

Table 3 Chromatographic resin systems for concentrating C5 and C6 alditols

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<td>Feed load</td><td>SMB A's No. 1 Resin Elution Rate</td><td>Elution rate of SMB B resin no. 2</td><td>SMBC Resin No. 3 Elution Rate</td><td>Elution rate of SMB D resin no. 4</td><td>SMB E Resin No. 5 Elution Rate</td>

<td>50% C5 alditols 50:50 X/A 50% C6 alditols 50:50 S/M</td><td>% recovery of xylitol 50%</td><td>% recovery of xylitol 65%</td><td>% recovery of xylitol 75%</td><td>% recovery of sorbitol 40%</td><td>% recovery of sorbitol 55%</td>

<td></td><td>% xylitol derivation for hydrotreatment 50%</td><td>% xylitol derivation for hydrotreatment 35%</td><td>% xylitol derivation for hydrotreatment 25%</td><td>% sorbitol derivatization for hydrotreatment 60%</td><td>% sorbitol derivatization for hydrotreatment 45%</td>

<td>Estimated Separation % Capex 90% Recovery = 1.00 or 100%</td><td> 0.4</td><td> 0.6</td><td> 0.75</td><td> 0.6</td><td> 0.8</td>

<td>Estimated Opex Separation % 90% Recovery = 1.00 or 100%</td><td> 0.3</td><td> 0.5</td><td> 0.8</td><td> 0.6</td><td> 0.8</td>

X = xylitol, A = arabitol, S = sorbitol, M = mannitol

Example 4. Concentration and crystallization of alditol

Alditols (xylitol, arabinitol, sorbitol, mannitol and other epimer alditols) have a maximum concentration of 25% solids in water after hydrogenation. This mixture can be further concentrated by moving bed chromatography using selected resins to retain C6 alditols and concentrate C5 in the permeate and/or by taking 25% alditol and through reverse osmosis or other water removal techniques and/or by selectively converting, for example, arabinatol to xylitol. Higher concentrations of alditols with a higher percentage of xylitol can be crystallized with or without the addition of antisolvents (e.g., e.g., ethanol) to facilitate crystallization.

Individual alditols have varying degrees of solubility in water, with sorbitol and arabitol having the highest solubilities, followed by xylitol and then mannitol at a given temperature. In addition, antisolvents, such as ethanol/water mixtures, used to solubilize alditols impact solubility. The higher the ethanol concentration, the lower the alditol's solubility. The combination of solubility differences and the possible use of ethanol in the extraction and crystallization stages makes it feasible to control the isolation of the product.

Table 4A summarizes the effect of xylitol concentration on xylitol crystallization. Table 4B summarizes the effect of ethanol/water solvent volume on xylitol crystallization.

<img file="MX391237B_D0029.tif" />

IMPI xylitol.

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W

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Table 4A Examples of xylitol feedstock concentration on crystallization yield

<td>Proof</td><td>% crystal seed</td><td>Initial xylitol concentration g/liter</td><td>Xylitol after evaporation g/liter</td><td>% total crystallization yield</td><td>% purity grade</td>

<td> 1</td><td> 1 %</td><td> 65.86</td><td> 632.33</td><td> 45.32</td><td> 98.47</td>

<td> 2</td><td> 1 %</td><td> 73.73</td><td> 691.98</td><td> 52.43</td><td> 97.32</td>

<td> 3</td><td> 1 %</td><td> 79.99</td><td> 750.00</td><td> 60.02</td><td> 95.00</td>

<td> 4</td><td> 1 %</td><td> 73.73</td><td> 908.27</td><td> 74.74</td><td> 80.77</td>

Table 4B Effects of ethanol/water volume on xylitol crystallization

<td>Proof</td><td>% crystal seed</td><td>Ethanol/water V:V</td><td>% crystallization after 24 hours</td><td>% crystallization after 48 hours</td><td>% purity grade</td>

<td> 1</td><td> 1 %</td><td> 1:3</td><td> 87.33</td><td> 95.35</td><td> 63.48</td>

<td> 2</td><td> 1 %</td><td> 1:2</td><td> 83.44</td><td> 90.66</td><td> 66.52</td>

<td> 3</td><td> 1 %</td><td> 1:1</td><td> 52.67</td><td> 56.67</td><td> 69.82</td>

<td> 4</td><td> 1 %</td><td> 0: 1</td><td> 23.53</td><td> 37.78</td><td> 97.57</td>

The combination to produce a variety of specific C5/C6 alditols (xylitol or sorbitol) from a corresponding mixed C5/C6 aldose feedstock (xylitol, arabitol, mannitol, galactitol, sorbitol) allows for the combined stepwise use of water solubility compared to a water/ethanol blended aldose with, for example, chromatography to concentrate xylitol or other alditols to levels suitable for extraction into a high purity cut. In turn, this purer cut can be recrystallized in stages to produce a series of higher purities (98% or more, for example).

In summary, the target alditols can be removed with most of the non-target alditols used for hydrogenolysis.

Example 5. Hydrogenolysis of alditol to produce glycols

Table 5A illustrates representative mixed alditols to glycols via hydrogenolysis. Note in the table that C5 xylitol, for example, produces more ethylene glycol.

<img file="MX391237B_D0030.tif" />

IMPI ω &lt;o

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Mexican Institute of Industrial Property (EG) (26%) than a corresponding C6 sorbitol feed EG (13%). Since the green EG used for renewable sustainable PET bottles is preferred in the market over conventional non-green EG, it illustrates the flexibility of the process developed in the present description. A propylene glycol (PG) focus would shift to a higher C6/C5 ratio. The resulting glycols PG, EG, GLY (glycerol) and BD (butanediol isomers) can be separated by classical distillation and/or extractive and azeotropic distillation.

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Table 5A Representative mixed alditols to glycols via hydrogenolysis

<td></td><td>Sorbitol C6</td><td>Xylitol C5</td><td>10% galactitol; 12% sorbitol; 23% arabitol; 55% xylitol</td><td>60% sorbitol 40% mannitol</td><td>75% xylitol; 25% sorbitol</td>

<td>Alditol concentration (% w/w)</td><td> 25 %</td><td> 22 %</td><td> 21 %</td><td> 21 %</td><td> 25 %</td>

<td>pH (base)</td><td>12.5 (NaOH)</td><td>12.4 (NaOH)</td><td>12.4 (NaOH)</td><td>12.4 (NaOH)</td><td>12.4 (NaOH)</td>

<td>Temperature °C</td><td> 214</td><td> 200</td><td> 193</td><td> 184</td><td> 200</td>

<td>Pressure kPa (psig)</td><td> 12,411 (1800)</td><td> 11,721 (1700)</td><td> 11,721 (1700)</td><td> 11,721 (1700)</td><td> 11,721 (1700)</td>

<td>LHSV (IT¹)</td><td> 1.5</td><td> 2</td><td> 2</td><td> 0.9</td><td> 2</td>

<td>H₂ (molar ratio)</td><td> 8</td><td> 8</td><td> 8</td><td> 8</td><td> 8</td>

<td>Yields based on mass: % of PG,</td><td> 33 %</td><td> 33 %</td><td> 30 %</td><td> 21 %</td><td> 31 %</td>

<td>% of EG,</td><td> 13 %</td><td> 26%</td><td> 23 %</td><td> 11 %</td><td> 25 %</td>

<td>% glycerol</td><td> 1 %</td><td> 10%</td><td> 11 %</td><td> 22 %</td><td> 10%</td>

<td>% of BD</td><td>ND</td><td>ND</td><td>ND</td><td>ND</td><td>ND</td>

<td>Catalyst</td><td>Ni/Cu in zirconia</td><td>Ni/Cu in Crzirconia</td><td>Ni/Cu in Cr-zirconia</td><td>Ni/Cu in Crzirconia</td><td>Ni/Cu in Crzirconia</td>

Example 6. Effect of sorbitol and mannitol on the purification of xylitol

Model crystallization liquor system mixtures containing varying amounts of xylitol, mannitol, sorbitol, and other sugars were prepared by dissolving mixtures of alditols and aldoses in water at 85 °C to give a solution with a total solids composition in % w/w of 15 as shown in Table 6. Each solution was then added to a crystallization vessel at 5 °C. The temperature of the vessel contents was monitored. At 30 °C, xylitol seed (3 g) was added along with 100 ml of ethanol (95%). The solid xylitol was removed by filtration after 1 hour.

<img file="MX391237B_D0031.tif" />

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Mexican Institute of Industrial Property after the seed. The data in Table 6 show the effect of sorbitol and mannitol concentrations on xylitol purification from the model systems.

Mannitol has a low solubility. As shown by the data in Table 6, at mannitol concentrations >10%, undesirable co-crystallization of mannitol 5 with xylitol is observed. When the mannitol content was 4% w/w less than the crystallization liquor, successful purification of xylitol was achieved.

Furthermore, it is shown by the data in Table 6 that sorbitol concentrations of >15% reduce the crystallization rate of xylitol and filtration rates are also reduced.

Table 6:

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<td>Test No.</td><td colspan="5">Entry percentages</td><td></td><td>Input polyol composition</td>

<td></td><td>Total solids (%)</td><td>Xylitol input (% polyols)</td><td>Xylitol yield (% of input)</td><td>Purity (%)</td><td>Other polyols (%)</td><td>Comment</td><td>Sorbitol (S) (%): Mannitol (M) (%) and galactitol (G) (%) (All contain 70% xylitol)</td>

<td> 01120</td><td> 60</td><td> 70</td><td> &lt;5</td><td>NA</td><td>NA</td><td>Very low performance</td><td>S(15%):M (15%)</td>

<td> 01118</td><td> 60</td><td> 70</td><td> &lt;5</td><td> 55</td><td> 45</td><td>Only visible seed</td><td>S(20%):M (10%)</td>

<td> 01077</td><td> 60</td><td> 70</td><td> 72</td><td> 33</td><td> 67</td><td>No comment</td><td>S(0%): M (30%)</td>

<td> 00939-3</td><td> 60</td><td> 70</td><td>No solids</td><td>N/A</td><td>N/A</td><td>No comment</td><td>S(30%):M (0%)</td>

<td> 00939-5</td><td> 75</td><td> 50</td><td>No solids</td><td>N/A</td><td>N/A</td><td>No comment</td><td>S(40%):M(5%):G(5%)</td>

<td> 00939-7</td><td> 75</td><td> 50</td><td> &gt;100</td><td>N/A</td><td>N/A</td><td>Very slow filtration</td><td>S(30%):M(15%):G(5%)</td>

<td> 00930</td><td> 75</td><td> 70</td><td> 81</td><td>N/A</td><td>N/A</td><td>Bulk crystallization - starts at 60 °C</td><td>S(0%):M (30%)</td>

<td> 00939-1</td><td> 75</td><td> 70</td><td> 60</td><td>N/A</td><td>N/A</td><td>Slow start of crystallization is filtered 2 hours after the seed</td><td>S(30%):M (0%)</td>

<td> 00948</td><td> 75</td><td> 70</td><td> 82</td><td> 60</td><td> 40</td><td>Very slow crystallization overnight at 5 °C</td><td>S(15%):M (15%)</td>

<img file="MX391237B_D0032.tif" />

IMPI

MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY ω &lt;o

M ω

<td>Test No.</td><td colspan="5">Entry percentages</td><td></td><td>Input polyol composition</td>

<td></td><td>Total solids (%)</td><td>Xylitol input (% polyols)</td><td>Xylitol yield (% of input)</td><td>Purity (%)</td><td>Other polyols (%)</td><td>Comment</td><td>Sorbitol (S) (%): Mannitol (M) (%) and galactitol (G) (%) (All contain 70% xylitol)</td>

<td> 00952</td><td> 75</td><td> 70</td><td> 88</td><td>N/A</td><td>N/A</td><td>Very slow crystallization overnight at 5 °C</td><td>S(20%):M (10%)</td>

<td> 00939-7</td><td> 75</td><td> 50</td><td></td><td>N/A</td><td>N/A</td><td>Very slow crystallization</td><td>S (30%):M (15%):(5%)</td>

<td> 00939-9</td><td> 80</td><td> 52</td><td> &gt;100</td><td>N/A</td><td>N/A</td><td>Bulk crystallization - difficult to filter, etc.</td><td>S (22%):M (20%):G (6%)</td>

<td> 00736</td><td> 85</td><td> 80</td><td> &gt;100</td><td>N/A</td><td>N/A</td><td>Difficult to dry</td><td>S(5%):M(10%):G(5%)</td>

<td> 00737</td><td> 85</td><td> 80</td><td> &gt;100</td><td>N/A</td><td>N/A</td><td>Difficult to filter and dry - exhibits some shear thinning/thixotropic behavior (qualitative observation)</td><td>S (5%):M (10%); G (5%)</td>

MX/a/2018/009634

Although the invention has been described with reference to an illustrative embodiment, those skilled in the art will understand that various changes are possible, and equivalents may be substituted for elements thereof without departing from the scope of the invention. Furthermore, any modifications may be made to adapt a particular situation or material to the descriptions of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment described as the best mode contemplated for carrying out this invention, but that the invention include all those that are within the scope of the appended claims.