Preparation of haloalkylfurfural compounds

Abstract

A process to obtain a halogenated methyl furfural from a high purity cellulose source, said process comprising the steps of: - providing a reaction vessel; - providing said high purity cellulose source into said reaction vessel, wherein said high purity cellulose source has a content of hemicellulose of less than 15 %, preferably less than 10 % and more preferably less than 5 %, and a Kappa number of less than 10, more preferably less than 5, and even more preferably, less than 2; - mixing said high purity cellulose source to a concentrated acid and an organic solvent at a reaction temperature ranging from 50 to 200 °C for a period of time sufficient to convert at least 75 % of the high purity cellulose source into said halogenated methyl furfural; - separating a resulting organic phase from an aqueous phase, wherein the organic phase comprises said halogenated methyl furfural and where the concentrated acid is comprised in said aqueous phase; - optionally, evaporating said organic solvent to yield said halogenated methyl furfural; and wherein said process yields less than 2.5 % of levulinic acid as a side product.

Description

[0001] PREPARATION OF HALOALKYLFURFURAL COMPOUNDS

[0002] FIELD OF THE INVENTION

[0003] The present invention is directed to a process of obtaining an haloalkylfurfural compound, more specifically, a process which employs cellulose as a starting material.

[0004] BACKGROUND OF THE INVENTION

[0005] Hydroxymethylfurfural (HMF), also known as 5-(hydroxymethyl)furfural, is an organic compound which comprises a furan ring, an aldehyde and alcohol functional groups. While it has limited applications, it is a very valuable small molecule as it can be converted to 2,5 -furandicarboxylic acid (2,5- FDCA); 2,5-dimethylfuran (DMF); 2,5-diformylfuran; 5 -methylfuran; 2,5-bis(hydroxymethyl)furan, and 1,6-hexanediol. Most of these compounds can be used in decarbonization efforts as biofuels and fuel additives or, in turn, be converted to other small molecules of great value. It is thus apparent that developing a method to manufacture HMF or a derivative thereof on a large scale at reduced costs would be highly advantageous.

[0006] The conventional process to generate hydroxymethylfurfural (see Figure 1) has low yields as it continues to react in the acidic environment in which it is made into levulinic acid, which corresponds to a ring-opened version of 5 -hydroxymethylfurfural, and other compounds such as polymeric humins. While levulinic acid is also a platform chemical with multiple uses, the conversion of 5-HMF into levulinic acid essentially closes the door on a number of other desirable chemical compounds. Researchers have tried to find uses for humins; however, none of them have materialized in a commercial scale and humins continue to be a major drawback of the synthesis of these halogenated methylfurfurals from sugars and biomass.

[0007] There has yet to be developed a method which yields 5-HMF precursors without generating a significant amount of levulinic acid and humin by-products. While HMF is somewhat unstable in an acidic environment, a workaround to this problem is to generate chloromethylfurfural (CMF) or 5- (chloromethyl)furfural .

[0008] Chloromethylfurfural is, itself, a valuable small chemical as it can be employed as a platform chemical in the synthesis of a plethora of other valuable small molecules. Additionally, its synthesis bypasses many of the drawbacks mentioned for the synthesis of HMF as it can be readily extracted in organic solvents, thus avoiding its degradation pathways in acidic environments. While the production of CMF from cellulose has been known for decades, its production continues to be plagued with issues including its poor selectivity. In addition to chloromethylfurfural, most synthetic routes reported to date also produce humins and other by-products including levulinic acid, 5- (hydroxymethyl)furfural, etc. Depending upon the nature of the feedstock, other by-products may include furfural, formic acid, gamma valerolactone, etc.

[0009] Examples of such include US Patent 11,299,468 B2, which provides methods to produce 5- (halomethyl)furfural, including 5-(chloromethyl)furfural, by acid-catalyzed conversion of C6 saccharides, including isomers thereof, polymers thereof, and certain derivatives thereof. The methods make use of acids with lower concentrations, and allows for conversion of sugars into 5-(halomethyl)furfural at higher temperatures and faster reaction or residence times.

[0010] Patent application number WO2019 / 149853A1 discloses a process for the conversion of a solid lignocellulosic material containing hemicellulose, cellulose and lignin, the process including the following steps: (a) hydrolyzing, at a temperature equal to or less than 40°C, preferably equal to or less than 30 °C, at least part of the hemicellulose and at least part of the cellulose of the solid lignocellulosic material with an aqueous hydrochloric acid solution, containing in the range from equal to or more than 40.0 wt. %to equal to or less than 51.0 wt. % hydrochloric acid, based on the combined weight amount of water and hydrochloric acid in such aqueous hydrochloric acid solution; yielding a hydrochloric acid-containing, aqueous hydrolysate solution; (b) separating the hydrochloric acid-containing, aqueous hydrolysate solution from the lignin; and (c) heating at least part of the hydrochloric acid-containing, aqueous hydrolysate solution to a temperature equal to or more than 60°C, yielding a product solution containing 5- (chloromethyl)furfural, and extracting the 5-(chloromethyl)furfural from such product solution into an extraction solvent.

[0011] US patent no. 7,829,732 teaches a method for preparing 5-(chloromethyl)furfural (CMF), or a derivative thereof, in greater than 50% yield, the method comprising: (a) contacting a polysaccharide, an aqueous acid and an organic solvent in a reaction vessel at a temperature of from about 30° C. to about 100° C., such that CMF is produced; (b) removing the organic solvent to an isolation vessel, such that any CMF dissolved in the removed organic solvent is collected in the isolation vessel; and(c) adding additional organic solvent to the reaction vessel, wherein steps (b) and (c) are performed continuously, thereby preparing CMF, or a derivative thereof, in greater than 50% yield from the polysaccharide. US patent no. 2023 / 0032460 Al provides methods to produce 5-(halomethyl)furfural, including 5- (chloromethyl)furfural, by acid-catalyzed conversion of C6 saccharides, including isomers thereof, polymers thereof, and certain derivatives thereof. The methods make use of acids with lower concentrations and allows for conversion of sugars into 5-(halomethyl)furfural at higher temperatures and faster reaction or residence times.

[0012] It is known by those skilled in the art that when employing a lignocellulosic material under acidic conditions, lignin depolymerization will occur. This acid-catalyzed depolymerization using acids such as sulfuric and hydrochloric acid has been extensively investigated. Post-depolymerization, condensation of the material formed is rapid and yields an insoluble material that has little to no value, thus severely limiting the valorization of all the components of the biomass. Said insoluble material is known to also adsorb chemicals and products, thus reducing overall reaction yields.

[0013] In light of the state of the art, there still exists a need for a method to generate a halomethylfurfural such as Chloromethylfurfural from a non-food source (such as cellulosic glucose) in order to yield a platform chemical at competitive cost. Furthermore, there is still a need for a method that selectively generates said halomethylfurfural and whereby any other impurities or by-products are generated in minimal amounts, so that to lower the costs associated with the purification of said halomethylfurfural.

[0014] SUMMARY OF THE PRESENT INVENTION

[0015] According to a first aspect of the present invention, there is provided a process to obtain a halogenated methyl furfural from a high purity cellulose source, said process comprising the steps of:

[0016] - providing a reaction vessel;

[0017] - providing said high purity cellulose source into said reaction vessel, wherein said high purity cellulose source has a content of hemicellulose of less than 15 %, preferably less than 10 % and more preferably less than 5 %, and a Kappa number of less than 10, more preferably less than 5, and even more preferably, less than 2;

[0018] - mixing said high purity cellulose source to a concentrated acid and an organic solvent at a reaction temperature ranging from 50 to 200 °C for a period of time sufficient to convert at least 75 % of the high purity cellulose source into said halogenated methyl furfural;

[0019] - separating a resulting organic phase from an aqueous phase, wherein the organic phase comprises said halogenated methyl furfural and where the concentrated acid is comprised in said aqueous phase;

[0020] - optionally, evaporating said organic solvent to yield said halogenated methyl furfural; and wherein said process yields less than 2.5 % of levulinic acid as a side product.

[0021] According to a preferred embodiment of the present invention, the process yields less than 1 % of levulinic acid.

[0022] According to a preferred embodiment of the present invention, the process yields less than 2.5 % of other by-products including furfural, 5-(hydroxymethyl)furfural, and gamma-valerolactone.

[0023] According to a preferred embodiment of the present invention, said organic solvent is a solvent non-miscible with water, such as that two phases are formed in the reaction vessel. Said organic solvent is a solvent in which 5-(chloromethyl)furfural is at least partially soluble in. Such solvents may include, but are not limited to, halogenated hydrocarbons (e.g., dichloromethane, chloroform, 1,2-dichloroethane), ethers (e.g., diethyl ether, methyl tert-butyl ether), aromatic hydrocarbons (e.g., toluene, xylene), aliphatic hydrocarbons (e.g., hexane, heptane), alcohols with limited water miscibility (e.g., tert-butanol), and other organic liquids (e.g., that do not readily mix with water under the reaction conditions. The choice of solvent may be adjusted depending on the substrate, desired reaction rate, selectivity, and ease of product separation. Biphasic solvent systems combining such water-immiscible organic solvents with an aqueous phase are particularly suitable, as they allow efficient extraction of the reaction product from the aqueous acidic phase while maintaining reaction control.

[0024] Preferably, said organic solvent is a halogenated solvent non-miscible with water. More preferably, said organic solvent is selected from the group consisting of: tetrachloromethane; trichloromethane; dichloromethane; chloromethane; hexachloroethane; pentachloroethane; 1,1,1,2-tetrachloroethane; 1, 1,2,2- tetrachloroethane; 1,1,2-trichloroethane; 1,1,1 -trichloroethane; 1,2-dichloroethane; 1,1 -dichloroethane; chloroethane; tetrachloroethene; trichloroethene; cA-l,2-dichloroethene; / ram- l .2-dichlorocthcnc: 1,1- dichloroethene; and chloroethene, their bromine equivalents; their iodine equivalents and combinations thereof.

[0025] According to a first aspect of the present invention, there is provided a process to obtain a halogenated methyl furfural from a pretreated lignocellulosic biomass, said process comprising the steps of: providing a lignocellulosic biomass; contacting said lignocellulosic biomass to a modified Caro’s acid composition for a period of time necessary to remove more than 98.5 % of the lignin present in said lignocellulosic biomass and thus obtaining a solid stream and a liquid stream, wherein said solid stream comprises a high purity cellulose source, and wherein said high purity cellulose source has a content of hemicellulose of less than 15 %, preferably less than 10 % and more preferably less than 5 %, and a Kappa number of less than 10, more preferably less than 5, and even more preferably, less than 2;

[0026] (a) mixing said solid stream in a reaction vessel with a concentrated acid and an organic-solvent at a reaction temperature ranging from 50 to 200 °C for a period of time sufficient to convert at least 75% of said solid stream into said halogenated methyl furfural;

[0027] (b) separating a resulting organic phase from an aqueous phase wherein the organic-phase comprises said halogenated methyl furfural and where the concentrated acid is present in said aqueous phase;

[0028] (c) optionally, evaporating said organic solvent to yield said halogenated methyl furfural; and wherein said process yields less than 2.5 % of levulinic acid as a side product.

[0029] According to a preferred embodiment of the present invention, said organic solvent is non-miscible with water, such as that two phases are formed in the reaction vessel. Said organic solvent is a solvent in which 5-(chloromethyl)furfural is at least partially soluble in. Such solvents may include, but are not limited to, halogenated hydrocarbons (e.g., dichloromethane, chloroform, 1,2-dichloroethane), ethers (e.g., diethyl ether, methyl tert-butyl ether), aromatic hydrocarbons (e.g., toluene, xylene), aliphatic hydrocarbons (e.g., hexane, heptane), alcohols with limited water miscibility (e.g., tert-butanol), and other organic liquids (e.g., that do not readily mix with water under the reaction conditions. The choice of solvent may be adjusted depending on the substrate, desired reaction rate, selectivity, and ease of product separation. Biphasic solvent systems combining such water-immiscible organic solvents with an aqueous phase are particularly suitable, as they allow efficient extraction of the reaction product from the aqueous acidic phase while maintaining reaction control.

[0030] According to a preferred embodiment of the present invention, the concentrated acid is preferably a halogenated acid. The halogen in the acid may correspond to the halogenated variety of the halogenated methylfurfural molecule being produced. The halogenated acid may be of mineral or organic origin, including, without limitation, hydrogen halides, halogenated sulfonic acids, or other halogen-containing acids known in the art. Preferably, the concentrated acid is a concentrated mineral acid, more preferably a concentrated hydrochloric acid or hydrobromic acid. According to a preferred embodiment of the present invention, a volume ratio of the organic solvent to the concentrated acid is 100: 1 to 1:50. Preferably, said volume ratio of the organic solvent to the concentrated acid is 50: 1 to 1:20. More preferably, said volume ratio of the organic solvent to the concentrated acid is 20: 1 to 1: 10.

[0031] According to a preferred embodiment of the present invention, said process further comprises the addition of an inorganic salt during the mixing step. The inorganic salt may be chosen based on the feedstock, reaction conditions, solvent, acid selection, and desired molecule. Preferably, said inorganic salt is a chloride or bromide salt of any group in the period table. More preferably, said inorganic salt is a chloride or bromide salt of Groups I, II, and III. More preferably, said inorganic salt is selected from the group consisting of: sodium chloride; potassium chloride; lithium chloride; calcium chloride; magnesium chloride; iron chloride; aluminum chloride; and combinations thereof. It is known to those skilled in the art that the bromide counterparts of said salts will be employed if the desired molecule is 5- (bromomethyl)furfural .

[0032] According to a preferred embodiment of the present invention, the salt is added as in a loading ranging from 0.1% w / w to 10% w / w of the total solvent weight. Preferably, the salt is added as in a loading ranging from 0.2 % w / w to 2.5% w / w of the total solvent weight.

[0033] According to a preferred embodiment of the present invention, the temperature ranges from 50 to 200 °C. Preferably, the temperature ranges from 75 to 150 °C. More preferably, the temperature ranges from 80 to 120 °C.

[0034] According to a preferred embodiment of the present invention, the vessel is a closed vessel where, during the mixing step, the vessel pressurizes by itself as it reaches said reaction temperature, and wherein the pressure ranges from 25 - 250 psi. In another embodiment of the present invention, the vessel is open and the pressure is atmospheric.

[0035] According to a preferred embodiment of the present invention, said lignocellulosic biomass was exposed to an acid solution to remove substantially all of the hemicellulose present in said biomass prior to the step of contacting said lignocellulosic biomass to a modified Caro’s acid composition. According to a preferred embodiment of the present invention, the lignocellulosic biomass was exposed to a caustic solution after the step of contacting said lignocellulosic biomass to a modified Caro’s acid composition, wherein the exposure to said caustic solution removes substantially all of the hemicellulose remaining in a modified Caro’s acid treated lignocellulosic biomass.

[0036] BRIEF DESCRIPTION OF THE FIGURES

[0037] Features and advantages of embodiments of the present application will become apparent from the following detailed description and the appended figures, in which:

[0038] Figure 1 is a chemical reaction flow chart showing the conversion of fructopyranose (1) to fructofuranose (2) to two intermediate stages of dehydration (compounds 3 and 4) which in turn yield HMF (5).

[0039] Figure 2 is a chromatograph of a chloromethyl furfural product obtained by the process according to a preferred embodiment of the present invention described herein

[0040] DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0041] The following description sets forth exemplary methods, parameters and the like. It should be recognized, however, that such description is not intended as a limitation on the scope of the present disclosure but is instead provided as a description of exemplary embodiments.

[0042] According to a preferred embodiment of the present invention, the method to generate halogenated methyl furfurals from a high purity cellulose source is not feedstock-dependent but delignification process dependent.

[0043] Any feedstock may be used as a source of six-carbon (C6) saccharides, however, it is preferable that any such feedstock be processed using a modified Caro’s acid as per the following. The feedstock may be lignocellulosic biomass which can originate from various sources including, but not limited to, agricultural materials (e.g. com stover), wood chips, saw dust, switchgrass, sorghum, bagasse, etc.

[0044] According to another aspect of the present invention, there is provided a method of converting lignocellulosic biomass a into high purity cellulose source; wherein said method comprising the steps of: providing said lignocellulosic biomass; processing said lignocellulosic biomass into processed particles of a size ranging of up to 6 inches; providing an acidic composition having a pH of less than 1, said acidic composition selected from the group consisting of: composition A; composition B; composition C; composition D; composition E; composition F; composition G; composition H; composition I; and composition J; wherein said composition A comprises: o sulfuric acid; o a compound comprising an amine moiety and a sulfonic acid moiety; and o a peroxide; and wherein sulfuric acid, said compound comprising an amine moiety and a sulfonic acid moiety and said peroxide are present in a molar ratio of no less than 1: 1:1; wherein said composition B comprises: o sulfuric acid; o a compound comprising an amine moiety; o a compound comprising a sulfonic acid moiety; and o a peroxide; wherein sulfuric acid and said a compound comprising an amine moiety and said compound comprising a sulfonic acid moiety are present in a molar ratio of no less than 1: 1: 1; wherein said composition C comprises: o an alkylsulfonic acid; and o a peroxide; wherein said alkylsulfonic acid and said peroxide are present in a molar ratio of no less than 1: 1; wherein said composition D comprises: o sulfuric acid; o a heterocyclic compound; and o a peroxide; and wherein sulfuric acid and said a heterocyclic compound; are present in a molar ratio of no less than 1: 1; wherein said composition E comprises: o sulfuric acid; o a modifying agent comprising a compound containing an amine group; and o a peroxide; and wherein sulfuric acid and said compound containing an amine group; are present in a molar ratio of no less than 1: 1; wherein said composition F comprises: o sulfuric acid; o a modifying agent comprising an alkane sulfonic acid and o a peroxide; and wherein sulfuric acid and said alkanesulfonic acid are present in a molar ratio of no less than 1: 1; wherein said composition G comprises: o sulfuric acid; o a substituted aromatic compound; and o a peroxide; and wherein sulfuric acid and said substituted aromatic compound; are present in a molar ratio of no less than 1: 1; wherein said composition H comprises: o sulfuric acid; o a modifying agent comprising an arylsulfonic acid; o a peroxide; and o optionally, a compound containing an amine group ; wherein sulfuric acid and said a arylsulfonic acid; are present in a molar ratio of no less than 1:1; wherein said composition I comprises: o sulfuric acid; o a heterocyclic compound; o an alkanesulfonic acid and o a peroxide; and wherein sulfuric acid and said a heterocyclic compound; are present in a molar ratio of no less than 1: 1; wherein said composition J comprises: o sulfuric acid; o a carbonyl-containing nitrogenous base compound; and o a peroxide; and wherein sulfuric acid and said a carbonyl-containing nitrogenous base compound; are present in a molar ratio of no less than 1: 1; exposing said processed particles to said acidic composition for a period of time sufficient to delignify said processed particles and yield a high purity cellulose source.

[0045] According to a preferred embodiment of the present invention, the sulfuric acid and the source of peroxide are present in a molar ratio ranging from 3 : 1 to 1 : 3. Preferably, the sulfuric acid and the modifying agent are present in a molar ratio ranging from 10: 1 to 1: 10. More preferably the sulfuric acid and the modifying agent are present in a molar ratio ranging from 3: 1 to 1:3. Even more preferably, the sulfuric acid and the modifying agent are present in a molar ratio ranging from 3 : 1 to 1: 1. According to a preferred embodiment of the present invention, the peroxide and the sulfuric acid are present in a molar ratio ranging from 1.5: l to 1: 10. Preferably, peroxide and the sulfuric acid are present in a molar ratio ranging from 1:3 to 1:7. More preferably, the peroxide and the sulfuric acid are present in a molar ratio of approximately 1:5.

[0046] According to a preferred embodiment of the present invention, the peroxide and the sulfuric acid are present in a molar ratio ranging from 1.5: 1 to 1: 10. Preferably, the peroxide and the sulfuric acid are present in a molar ratio ranging from 1: 1 to 1:3. More preferably, the peroxide and the sulfuric acid are present in a molar ratio of approximately 1: 1.

[0047] According to an embodiment of the present invention, the lignocellulosic biomass may be pretreated with an acid to remove a substantial portion of the hemicellulose present in the biomass. Such removal of the hemicellulose allows one to obtain a purer cellulose after delignification as described hereinabove. Alternatively, a delignified lignocellulosic biomass may treated with a caustic solution to remove the hemicellulose remaining among the cellulose. This also, has for effect, to generate a purer cellulose to use in the preparation of CMF and related compounds. The thus removed hemicellulose can be precipitated and utilized in this process to access other derivatives such as furfural if said hemicellulose is treated according to the present invention.

[0048] According to a preferred embodiment of the present invention, the process to obtain a halogenated methyl furfural from the above obtained high purity cellulose source, comprises the steps of:

[0049] (d) providing a reaction vessel;

[0050] (e) providing said high purity cellulose source into said reaction vessel, wherein said high purity cellulose source has a content of hemicellulose of less than 15 %, preferably less than 10 % and more preferably less than 5 %, and a Kappa number of less than 10, more preferably less than 5, and even more preferably, less than 2;

[0051] (f) mixing said cellulose source to a concentrated acid and an organic solvent at a reaction temperature ranging from 50 to 200°C for a period of time sufficient to convert at least 75 % of the high purity cellulose source into said halogenated methyl furfural;

[0052] (g) separating a resulting organic phase from an aqueous phase, wherein the organic phase comprises said halogenated methyl furfural and where the concentrated acid is comprised in said aqueous phase, and;

[0053] (h) optionally, evaporating said organic solvent to yield said halogenated methyl furfural; wherein said process yields less than 2.5 % of levulinic acid as a side product. Preferably, the acid used in the process to obtain a halogenated methyl furfural is a halogencontaining acid such as, but not limited to, hydrochloric acid or hydrobromic acid. When using hydrochloric acid, the resulting halogenated compound will be 5-(chloromethyl)furfural (CMF). When using hydrobromic acid, the resulting halogenated compound will be 5-(bromomethyl)furfural (CMF).

[0054] According to a preferred embodiment of the method of the present invention, the acid concentration necessary to convert cellulose to a halogenated methyl furfural from a high purity cellulose source is present in sufficient quantities to allow the reaction to occur. Preferably, the acid concentration is greater than 0.001 M, more preferably the acid concentration is greater than 0. 1 M. More preferably, the acid concentration in the mixture comprising the high purity cellulose and the acid is at least 5 M. The person skilled in the art will understand that the acid concentrations as mentioned above can refer to the initial concentration or to a steady-state concentration when the method is carried out in a continuous manner.

[0055] According to a preferred embodiment of the present invention, said process further comprises the addition of an inorganic salt during the mixing step. The inorganic salt may be chosen based on the feedstock, reaction conditions, solvent, and acid selection. Preferably, said inorganic salt is a chloride salt of any group in the period table. More preferably, said inorganic salt is a chloride salt of Groups I, II, and III. More preferably, said inorganic salt is selected from the group consisting of: sodium chloride; potassium chloride; lithium chloride; calcium chloride; magnesium chloride; iron chloride; aluminum chloride; and combinations thereof.

[0056] A solvent, or a combination or mixture of solvents, may also be optionally added to the reaction mixture. Only suitable solvents are considered to be within the scope of the present invention. To be suitable, a solvent system that can form a liquid / liquid biphasic reaction mixture may be used, one phase being aqueous and at least another phase being organic phase. The majority of the resulting product will be found in the organic solvent phase as the product is not very soluble in the aqueous phase

[0057] According to a preferred embodiment of the present invention, said organic solvent is non-miscible with water, such as that two phases are formed in the reaction vessel. Said organic solvent is a solvent in which 5-(chloromethyl)furfural is at least partially soluble in. Such solvents may include, but are not limited to, halogenated hydrocarbons (e.g., dichloromethane, chloroform, 1,2-dichloroethane), ethers (e.g., diethyl ether, methyl tert-butyl ether), aromatic hydrocarbons (e.g., toluene, xylene), aliphatic hydrocarbons (e.g., hexane, heptane), alcohols with limited water miscibility (e.g., tert-butanol), and other organic liquids (e.g., that do not readily mix with water under the reaction conditions. The choice of solvent may be adjusted depending on the substrate, desired reaction rate, selectivity, and ease of product separation. Biphasic solvent systems combining such water-immiscible organic solvents with an aqueous phase are particularly suitable, as they allow efficient extraction of the reaction product from the aqueous acidic phase while maintaining reaction control. According to a preferred embodiment of the present invention, the organic solvent is selected from the group consisting of: tetrachloromethane; trichloromethane; dichloromethane; chloromethane; hexachloroethane; pentachloroethane; 1,1,1,2-tetrachloroethane; 1,1,2,2-tetrachloroethane; 1,1,2-trichloroethane; 1,1,1 -trichloroethane; 1,2-dichloroethane; 1,1 -dichloroethane; chloroethane; tetrachloroethene; trichloroethene; cA-l,2-dichloroethene; / ram- l .2-dichlorocthcnc: 1,1 -dichloroethene; and chloroethene, their bromine and iodine equivalents and / or combinations thereof.

[0058] According to a preferred embodiment of the present invention, a volume ratio of the organic solvent to the concentrated acid ranges between 100: 1 to 1:50. More preferably, the volume ratio of the organic solvent to the concentrated acid ranges between 50: 1 to 1 : 20. Even more preferably, the volume ratio of the organic solvent to the concentrate acid ranges between 20: 1 to 1: 10.

[0059] Preferably, the amount of solvent used ranges from 1 L per gram of high purity cellulose source to 100 m per 40 grams of high purity cellulose.

[0060] According to a preferred embodiment of the present invention, a combination of solvent described hereinabove can be employed.

[0061] According to a preferred embodiment of the present invention, a salt as described hereinabove and an acid described hereinabove may be varied in quantity of each individual components to optimize one or more aspects of the process described herein.

[0062] Preferably, in a view to optimize various parameters of the process described herein various acid, solvent and salt combinations may be employed without departing from the scope of the present invention. Such parameters include, but are not limited to, temperature of the reaction mixture, extent of reaction (conversion), duration of the reaction, type of vessel to name a few. The reaction temperature is to be understood as the temperature of the reaction mixture during the reaction to convert at least a portion of the high purity cellulose source into the desired product, 5-(halomethyl)furfural. Preferably, the reaction temperature ranges between 50°C and 150° C, more preferably between 75° C and 120° C, even more preferably between 80°C and 110° C. According to a preferred embodiment of the present invention, the reaction is carried out for a period of time lasting between 5 minutes and 10 hours. More preferably, the reaction is carried out for a period of time lasting between 15 minutes and 5 hours. Yet, even more preferably, the reaction is carried out for a period of time lasting between 30 minutes and 2 hours.

[0063] According to a preferred embodiment of the present invention, the reaction is carried out in a closed vessel. Preferably, the pressure inside the vessel during the reaction ranges from 25 psi to 250 psi. More preferably, the pressure inside the vessel during the reaction ranges from 50 to 200 psi. Even more preferably, the pressure inside the vessel during the reaction ranges from 50 to 100 psi.

[0064] According to a preferred embodiment of the present invention, the duration of the reaction is tailored to achieve a desired outcome for the operator carrying out the process. In some embodiments, the operator may want to limit the temperature and thus will modify the process duration accordingly. In some embodiments, the operator may want to limit the pressure inside the vessel and thus will modify the process duration accordingly. In some embodiments, the operator may want use a lower acid concentration and thus will modify the process duration accordingly. It is to be understood that many other specific situations or circumstances may arise which will require an operator to adapt the process along its parameters to achieve a desired outcome, none of these modifications are to be understood as being outside the scope of the present invention.

[0065] According to a preferred embodiment of the present invention, the haloalkylfurfural generated and present in the reaction mixture is present in both the aqueous phase and the organic phase. To isolate the product, the organic phase is separated from the aqueous phase to isolate the product-containing phase. Said phase can then be separated from the haloakylfurfural using techniques known to those skilled in the art.

[0066] According to a preferred embodiment of the present invention, the isolated haloalkylfurfural is purified by using any known purification method, including but not limited chromatography, distillation, or recrystallization.

[0067] Preferably, the vessels used during the process according to a preferred embodiment of the present invention, need to be able to withstand the acid used as well as the temperatures and pressures employed during the conversion reaction. It is to be understood by the person skilled in the art that other types of vessel may be employed but attention needs to be paid to their limitations in terms of corrosiveness, temperature and pressure.

[0068] According to a preferred embodiment of the present invention, the method described herein is designed to generate 5-(halomethyl)furfural while minimizing the side products such as levulinic acid, furfural, 5-(hydroxymethyl)furfural, gamma-valerolactone, etc. To do so, results in a method which can be commercially implemented and which will require substantially less purification (to remove side products) efforts than what is currently being commercially employed.

[0069] Yield of the reaction

[0070] According to a preferred embodiment of the present invention, the method can provide yields of 5- (halomethyl)furfural yield of 40% or more. More preferably, the method can provide yields of 60%. Even more preferably, the method can provide yields of 80%. Even more preferably, the method can provide yields of 85%.

[0071] In the context of this invention, conversion is referred to as the amount of initial material that has undergone any transformation under the conditions of the invention described herein, whereas yield is referred to the specific amount of a certain substance obtained with respect to the theoretical maximum amount of said substance that can be obtained from a given substrate.

[0072] Experiment # 1

[0073] Two different feedstocks were used in this experiment: a pretreated canola straw, as well as a delignified cellulose material obtained from the delignification using a modified Caro’s acid according to an embodiment of the present invention. The pretreated canola was obtained by exposing canola biomass to a dilute acid pretreatment using 4.5 % w / w sulfuric acid. This pretreatment simulated an acid pretreatment whose objective is to remove the hemicellulosic portion of the lignocellulosic biomass.

[0074] All materials were exposed in a closed vessel to a mixture of concentrated hydrochloric acid and a chlorinated organic solvent. The ratio of concentrated hydrochloric acid to chlorinated organic solvent was 1:2. For the purpose of this example, 1,2-dichloroethane was used; however, it is known to those skilled in the art that any other non-water miscible organic solvent could also be employed. LiCl was added as in a loading of 1.6 % w / w of the total solvent weight to aid in the reaction kinetics. The vessel was heated to a temperature between 80 and 120 °C while stirring. At the end of the reaction period, the vessel was cooled, and the two phases were separated using liquid-liquid extraction techniques. The resulting material was weighed to determine crude yields as well as sent for Nuclear Magnetic Resonance analysis to characterize its composition and determine specific compound yields. Details of the reactions are shown in Table 1. Conversion yields were calculated by subtracting any unreacted materials and solids obtained after the reaction is complete, while crude yields were obtained from the portion extracted in the organic solvent and CMF selectivity yields were obtained from the molar ratio obtained in the NMR analysis with respect to other by-products that may be obtained in these reactions.

[0075] Table 1: Reactions and yields obtained from Experiment #1

[0076] The results in Table 1 show significant advantages in terms of yields and selectivity of the product obtained when a delignified cellulose is used in the process according to this invention. Almost quantitative conversion yields are obtained from delignified cellulose as opposed to the other feedstock. It is known to those skilled in the art that conversion yields will be lower with the presence of lignin in the feedstock as lignin is recalcitrant under the conditions of the process described herein. It is nevertheless important to note that the reactions that employed pretreated canola straw showed a residue, presumably lignin, that was not converted. The presence of this residue is detrimental to large scale operations wherein said residues will cause build up issues in vessels that can lead to increased cleaning requirements and thus, lower operational availability. These residues, in most cases, have limited to no value and are treated as waste, therefore underutilizing a portion of the lignocellulosic biomass that can be used for other applications. When using the cellulosic material derived from the delignification described herein, the lignin component is depolymerized, and additional functionalities and applications are unlocked for increased revenue.

[0077] Additionally, as seen in Table 1, the selectivity of 5 -(chloromethyl) furfural (CMF) is considerably higher, which signifies that the process described herein does not require any additional purification steps, thereby saving on energy and costs associated with distillation and separation steps. This exceptional selectivity is a result of the high purity of the cellulose source material employed. This highlights the importance of using for this conversion a material obtained from the delignification of biomass using a modified Caro’s acid. Experiment #2

[0078] Experiment #2 demonstrates the effect of varying times on the production of CMF and other byproducts from a delignified cellulosic feedstock. It is known by those skilled in the art that other by-products will be formed under the conditions of the conversions described herein. Amongst some of those byproducts, levulinic acid stands out for its versatility in industrial applications and financial value. Those are reasons why it was selected to be quantified in this experiment. It is important to note that the yields reported herein are of the material obtained in the organic phase. It is expected that depending on the solubility in the solvents used, more levulinic acid may be obtained from its extraction of the aqueous phase and thus, the results reported in Table 2 are an underestimation of the yield of said by-product.

[0079] In the reactions, the cellulosic material was exposed in a closed vessel to a mixture of concentrated hydrochloric acid and a chlorinated organic solvent as per the details shown in Experiment #1 during different times to assess the effect of time on reaction yields. In some embodiments of the present invention, the cellulosic material is added in a wet form, where the solids content may range from 5 to 100 % solids w / w. Details of the reactions and resulting products are set out in Table 2.

[0080] Table 2: Reactions and yields obtained from Experiment #2

[0081] Table 2 indicates that CMF yields increase with decreased reaction times, which showcases the attractiveness of this process as it decreases operational times and maximizes production output. Additionally, with lower reaction times, the product obtained is of higher purity minimizing costly separation and purification yields. The results of this Experiment also highlight the versatility of this conversion, wherein the reaction parameters can be tailored to conveniently produce to high value chemicals in high yields. Preferably also, the proposed process can yield the targeted product with very little impurity levels. Impurities include, but are not limited to, levulinic acid and derivatives thereof.

[0082] Experiment #3

[0083] In this experiment three different feedstock loadings were used to evaluate the effect of cellulose loading on CMF yields. The four selected loadings were 1.0 % (Experiment 1), 1.5 %, 3.0 %, 4.5 % of delignified cellulose material. Table 3 lists the yields of CMF of each reaction as well as the quantified content of levulinic acid. Levulinic acid was quantified in the CMF sample using GC-FID.

[0084] Table 3: Cellulose loading and yields obtained from Experiment #3

[0085] Table 3 demonstrates that the yield of CMF decreases as the loading of delignified cellulose in the reactor increases. It is known by those skilled in the art that higher substrate loading can promote undesirable side reactions such as a the formation of humins and other unwanted by-products through condensation reactions. This secondary reaction adversely impacts the overall yield of CMF, reducing production efficiency. Notwithstanding the decline in yield with increasing cellulose concentration, Table 3 illustrates that the purity of the CMF product remains high with the content of levulinic acid in the product at or below 2.0 % in all cases. Figure 2 shows a chromatograph of the product highlighting the high purity. The results of these experiments further demonstrate the flexibility of the disclosed conversion process, as reaction parameters can be readily adjusted to selectively produce high-value compounds in elevated yields and excellent purity profiles.

[0086] Through the experimentation described in the present disclosure, it has been clearly observed that the selectivity toward the halogenated methyl furfural, in this case 5-(chloromethyl)fiirfural is significantly higher than that reported in prior art, including but not limited to Patents US 10,011,577B2, US 11,299,468B2, US 10,710,970B2, and US 12,281,089B2. This improvement underscores the need for and advantage of the process disclosed herein, wherein the formation of by-products is substantially minimized. The presence of by-products such as furfural and levulinic acid is undesirable, as their separation can be cumbersome and costly. Moreover, such by-products may interfere with subsequent chemical transformations when further derivatization or downstream processing is required, thereby reducing overall reaction yields and process efficiency.

[0087] While the foregoing invention has been described in some detail for purposes of clarity and understanding, it will be appreciated by those skilled in the relevant arts, once they have been made familiar with this disclosure that various changes in form and detail can be made without departing from the true scope of the invention in the appended claims.

Claims

CLAIMS1. A process to obtain a halogenated methyl furfural from a high purity cellulose source, said process comprising the steps of:- providing a reaction vessel;- providing said high purity cellulose source into said reaction vessel, wherein said high purity cellulose source has a content of hemicellulose of less than 15 %, preferably less than 10 % and more preferably less than 5 %, and a Kappa number of less than 10, more preferably less than 5, and even more preferably, less than 2;- mixing said high purity cellulose source to a concentrated acid and an organic solvent at a reaction temperature ranging from 50 to 200 °C for a period of time sufficient to convert at least 75 % of the high purity cellulose source into said halogenated methyl furfural;- separating a resulting organic phase from an aqueous phase, wherein the organic phase comprises said halogenated methyl furfural and where the concentrated acid is comprised in said aqueous phase;- optionally, evaporating said organic solvent to yield said halogenated methyl furfural; and wherein said process yields less than 2.5 % of levulinic acid as a side product.

2. The process according to claim 1 where the process yields less than 1 % of levulinic acid.

3. The process according to claim 1 wherein said organic solvent is a solvent non-miscible with water.

4. The process according to claim 1 wherein said organic solvent is a halogenated solvent non- miscible with water.

5. The process according to claim 1 , wherein said organic solvent is selected from the group consisting of: tetrachloromethane; trichloromethane; dichloromethane; chloromethane; hexachloroethane; pentachloroethane; 1,1,1,2-tetrachloroethane; 1,1,2,2-tetrachloroethane; 1,1,2-trichloroethane; 1,1,1- trichloroethane; 1,2-dichloroethane; 1,1 -dichloroethane; chloroethane; tetrachloroethene; trichloroethene; c7.s- l .2-dichlorocthcnc: / ram- l .2-dichlorocthcnc: 1,1 -dichloroethene; and chloroethene, their bromine equivalents; their iodine equivalents and combinations thereof..

6. A process to obtain a halogenated methyl furfural from a pretreated lignocellulosic biomass, said process comprising the steps of: providing a lignocellulosic biomass;contacting said lignocellulosic biomass to a modified Caro’s acid composition for a period of time necessary to remove more than 98.5 % of the lignin present in said lignocellulosic biomass and thus obtaining a solid stream and a liquid stream, wherein said solid stream comprising a high purity cellulose source, and wherein said high purity cellulose source has a content of hemicellulose of less than 15 %, preferably less than 10 % and more preferably less than 5 %, and a Kappa number of less than 10, more preferably less than 5, and even more preferably, less than 2;(a) mixing said solid stream in a reaction vessel with a concentrated acid and an organic solvent at a reaction temperature ranging from 50 to 200 °C for a period of time sufficient to convert at least 75% of said solid stream into said halogenated methyl furfural;(b) separating a resulting organic phase from an aqueous phase wherein the organic phase comprises said halogenated methyl furfural and where the concentrated acid is present in said aqueous phase;(c) optionally, evaporating said organic solvent to yield said halogenated methyl furfural; and wherein said process yields less than 2.5 % of levulinic acid as a side product.

7. The process according to claim 1 or 6, wherein said organic solvent is a halogenated solvent, preferably a chlorinated solvent, more preferably a short chain (C1-C4) chlorinated alkane.

8. The process according to any one of claims 1 to 7, wherein concentrated acid is preferably a concentrated mineral acid, more preferably a concentrated hydrochloric acid or hydrobromic acid.

9. The process according to any one of claims 1 to 8, wherein a volume ratio of the organic solvent to the concentrated acid is 100: 1 to 1:50.

10. The process according to any one of claims 1 to 8, wherein a volume ratio of the organic solvent to the concentrated acid is 50: 1 to 1:20.

11. The process according to any one of claims 1 to 8, wherein a volume ratio of the organic solvent to the concentrated acid is 20: 1 to 1: 10.

12. The process according to any one of claims 1 to 11, further comprising the addition of an inorganic salt during the mixing step.

13. The process according to claim 12, wherein said inorganic salt is a halide salt.

14. The process according to claim 12, wherein said inorganic salt is selected from the group consisting of: sodium chloride; potassium chloride; lithium chloride; calcium chloride; magnesium chloride; iron chloride; aluminum chloride; their bromide counterparts and combinations thereof.

15. The process according to any one of claims 1 to 14, wherein the salt is added as in a loading ranging from 0.1% w / w to 10% w / w of the total solvent weight.

16. The process according to any one of claims 1 to 15, wherein the salt is added as in a loading ranging from 0.2 % w / w to 2.5% w / w of the total solvent weight.

17. The process according to any one of claims 1 to 16, wherein said temperature ranges from 75 to 150°C.

18. The process according to any one of claims 1 to 17, wherein said temperature ranges from 80 to 120°C.

19. The process according to any one of claims 1 to 18, wherein said vessel is a closed vessel where, during the mixing step, the vessel pressurizes by itself as it reaches said reaction temperature, and wherein the pressure ranges from 25 - 250 psi.

20. The process according to any one of claims 6 to 19, wherein said lignocellulosic biomass was exposed to an acid solution to remove substantially all of the hemicellulose present in said biomass prior to the step of contacting said lignocellulosic biomass to a modified Caro’s acid composition.

21. The process according to any one of claims 6 to 19, wherein said lignocellulosic biomass was exposed to a caustic solution after the step of contacting said lignocellulosic biomass to a modified Caro’s acid composition, wherein the exposure to said caustic solution removes substantially all of the hemicellulose remaining in a modified Caro’s acid treated lignocellulosic biomass.

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