Extraction of 5-chloromethylfurfural from cellulosic and synthetic non-cellulosic fibers hydrolyzed with hydrochloric acid using organic solvents

Abstract

A method for obtaining chemical building blocks from textile materials containing cellulose fibers, such as cotton, and polyester, polyethylene or polypropylene, polyamide or elastane fiber materials, said method comprising hydrolyzing the cellulose by a process that does not affect the polyester, polyolefin, polyamide or elastane fiber materials, and converting the hydrolyzed cellulose into useful chemical building blocks.

Description

[Technical field]

[0001] The present invention relates to a method for treating textile materials, which comprises cellulosic fiber materials (e.g. from cotton, flax, jute, ramie, hemp, piña and abaca) and non-cellulosic synthetic polymeric fiber materials, such as polyester and / or polyolefin (polyethylene or polypropylene), polyamide fiber materials or elastane fiber materials. The treatment involves hydrolyzing at least a portion of the cellulosic fiber materials (e.g. cotton) present in the mixed textile material with concentrated hydrochloric acid and converting the hydrolyzed cellulose to 5-(chloromethyl)furfural (5-CMF). The 5-CMF thus obtained can be further processed, for example, to 5-(hydroxymethyl)furfural, 5-alkoxymethylfurfural, 5-(acetoxymethyl)furfural, methylfurfural or isolated as 5-CMF. [Background technology]

[0002] Patent application WO 2019 / 149843 discloses a method for obtaining chemical building blocks from solid lignocellulosic materials such as wood waste. Such lignocellulosic materials contain hemicellulose, cellulose, and lignin as main fractions. The method of the referenced patent application first subjects the substantially dried lignocellulosic material to hydrolysis at room temperature with a concentration of 15-40% hydrochloric acid, which removes the hemicellulose from the lignocellulosic material and thus from the reactor. The remaining material is then subjected to hydrolysis at room temperature with a concentration of 40-51% hydrochloric acid, which removes the cellulose fraction from the reactor, leaving a solid lignin residue in the reactor. The method continues by heating the resulting cellulose hydrolysate (still containing hydrochloric acid next to carbohydrates such as glucose and glucose oligomers) to yield 5-(chloromethyl)furfural (5-CMF). The 5-CMF thus obtained can be extracted with a solvent. 5-CMF can be converted into a variety of other chemicals and is therefore a convenient chemical building block. Similar to the above references, WO 2014 / 066746 discloses a method for producing 5-(chloromethyl)furfural by acid-catalyzed conversion of biomass.

[0003] Cellulose is also present as cellulose fibers in fabrics, such as, for example, clothing fabrics. Cellulosic fiber materials, such as cotton, have many uses, for example, in fabrics for use in clothing. Such clothing has a certain life span, for example, due to wear and tear. The end of life of cotton-containing clothing often means ending up in landfill or waste incineration with or without energy recovery, possibly after recycling and adaptation for other uses. Furthermore, landfill as a destination for used clothing is considered undesirable, and recycling is investigated. Recycling high-value cotton fibers into new cellulose-containing fibers for use in clothing fabrics is often not possible, since cotton (and other cellulose fibers) are generally used in fabrics mixed with other fibers, such as polyester (in various amounts), to give the fabric desired properties (e.g., strength, cost-effectiveness, ease of manufacture, etc.). Fabrics containing such mixtures of cellulose and non-cellulose fibers have so far been difficult or impossible to recycle into valuable products. Even clothing designated as 100% cotton often has polyester thread seams, which are also "mixed fabrics." To avoid ending up in landfills or incineration facilities, such mixed fabrics are used to make rags, for example. Because rags (for industrial cleaning, for example) are low-value products and there are limited uses for such products, they are reused as fabrics, but are down-cycled rather than recycled.

[0004] Cellulosic fibers are also used as raw materials for medical wipes for cleaning and / or disinfection, etc., which find application in hospitals, care facilities, and medical service centers involved in vaccination and testing for infectious diseases, etc. To minimize the risk of contamination or infection of patients and staff, such medical wipes are used in abundance and are single-use. Obviously, this results in a large amount of waste of such fabrics. All kinds of materials are used for medical wipes, but many contain cotton and non-cellulosic synthetic fibers, such as polyester. Reuse is largely impossible or undesirable, and the materials are usually incinerated after disposal. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 149843 [Patent Document 2] International Publication No. 2014 / 066746 [Non-patent literature]

[0006] [Non-Patent Document 1] S. Bandibairanahalli Onkarappa, Chemistry Select, 2019, vol. 4, pp. 5540-5543 Summary of the Invention [Problem to be solved by the invention]

[0007] It would therefore be desirable to be able to convert discarded clothing or fabrics, such as medical wipes made from fabrics containing both cotton or other cellulosic fibers and non-cellulosic fibers such as polyester (typically PET), into products of greater value than rags, to serve as an alternative to being incinerated or used as a landfill.Similarly, there is a need for methods that allow chemical building blocks to be made from sources that are not entirely based on fossil carbon sources. [Means for solving the problem]

[0008] The above relates to a method for treating a mixed fabric, the mixed fabric comprising 30-99% by weight of cellulose fiber material and 1-70% by weight of one or more of synthetic polyester fiber material, polyethylene fiber material, polypropylene fiber material, polyamide fiber material or elastane fiber material, the method comprising: a. In the reactor: - The mixed fabric material contains 30 to 99% by mass of cellulose fiber material and 1 to 70% by mass of one or more of synthetic polyester fiber material, polyethylene fiber material, polypropylene fiber material, polyamide fiber material, or elastane fiber material. - An aqueous solution of hydrochloric acid having a hydrochloric acid concentration of 30% to 45% (by mass) an organic extraction solvent selected such that at 20° C., less than 1 g of the extraction solvent is dissolved in 100 ml of aqueous HCl, and the organic extraction solvent is further selected such that at 20° C., at least 10 g of 5-(chloromethyl)furfural (5-CMF) can be dissolved in 100 ml of the organic extraction solvent; The process of preparing b. mixing the contents of the reactor at a temperature between 40° C. and 110° C. for at least 30 minutes, wherein the aqueous solution and the organic extractant are present in the reactor in a ratio of aqueous solution:organic extractant between 1:0.5 and 1:10. c. Separating the organic extractant containing 5-(chloromethyl)furfural (5-CMF) from the aqueous solution containing hydrochloric acid. It has now been found that the object can be achieved, at least in part, by a method for treating a mixed fabric, comprising:

[0009] Alternatively, based on the same principle, the above also relates to a method for treating a mixed fabric, the mixed fabric comprising cellulose fiber material in an amount of 30-99% by weight and one or more of synthetic polyester fiber material, polyethylene fiber material, polypropylene fiber material, polyamide fiber material or elastane fiber material in an amount of 1-70% by weight, the method comprising: a. In the reactor: - The mixed fabric material contains 30 to 99% by mass of cellulose fiber material and 1 to 70% by mass of one or more of synthetic polyester fiber material, polyethylene fiber material, polypropylene fiber material, polyamide fiber material, or elastane fiber material. - An aqueous solution of hydrochloric acid having a hydrochloric acid concentration of 36% to 51% (by mass) The process includes the steps of: at least partially hydrolyzing the cellulose of the cellulosic fibrous material for a period of at least 30 minutes and at a temperature of less than 40° C. to produce an aqueous hydrolysate and a solid fibrous residue. removing a solid fibrous residue from the product of c. mixing the aqueous hydrolyzate obtained by b. with an organic extraction solvent at a temperature between 50°C and 110°C for at least 30 minutes, wherein the aqueous solution and the organic extraction solvent are present in the reactor in a ratio of aqueous solution:organic extraction solvent between 1:0.5 and 1:10, the organic extraction solvent being selected such that at 20°C, less than 1 g of the extraction solvent dissolves in 100 ml of the aqueous HCl solution, and the organic extraction solvent is further selected such that at 20°C, at least 10 g of 5-(chloromethyl)furfural (5-CMF) can be dissolved in 100 ml of the organic extraction solvent. d. Separating the organic extractant containing 5-(chloromethyl)furfural (5-CMF) from the aqueous solution containing hydrochloric acid. This may be achieved, at least in part, by a method of treating the mixed fabric, comprising: DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The above two methods are two embodiments of the same invention, which reside in the fact that the cellulose of a fiber blend containing both cellulose and synthetic polyester, polyolefin, polyamide and elastane fibers can be used as a source of 5-(chloromethyl)furfural (5-CMF) by hydrolysis of the cellulose, followed by conversion of glucose / glucose oligomers to 5-CMF by the action of hydrochloric acid, and extraction of the 5-CMF with an organic extractant, while the synthetic polyester, polyolefin, polyamide and elastane fibers are left largely or completely physically intact. In this method, the synthetic polyester, polyolefin, polyamide and elastane fibers are resistant to the action of hydrochloric acid.

[0011] In the method according to the invention, the stage in which hydrochloric acid is reacting with cellulose is preferably carried out for a period during which at least 50% (by mass) of the cellulose fiber material is hydrolyzed, preferably for a period during which at least 70% of the cellulose fiber material is hydrolyzed. The actual time depends, for example, on the temperature, the nature of the fiber, and other process parameters, and can be easily determined by a person skilled in the art. Typically, it takes at least 30 minutes, but may be carried out for longer, for example, at least 1 hour, or preferably 2 hours or more. However, this stage should preferably not last longer than 12 hours, more preferably not longer than 10 hours, and even more preferably not longer than 6 hours.

[0012] It will be apparent to one skilled in the art that the mixing steps of step b. (first embodiment) and step c. (second embodiment) should be fairly vigorous when two largely immiscible liquids are present, and the 5-CMF formed in the aqueous phase needs to "transfer" to the organic extractant.

[0013] As mentioned above, until now, for example, mixed fiber blends of cotton and one or more of polyester, polyolefin, polyamide, or elastane have not often been used for anything other than rags or incineration after use for what the fiber blends are designed for (such as clothing, cleaning, protection, domestic use such as curtains, etc.). Surprisingly, it has been found by the above method that mixed fiber blends of cotton and one or more of polyester fibers (e.g., PET), polyolefin fibers, polyamide fibers, or elastane fibers are suitable as a source for producing the useful chemical intermediate compound 5-(chloromethyl)furfural (5-CMF). Even more surprisingly and advantageously, the method according to the invention allows residual synthetic polymeric materials, such as PET, to be mechanically or chemically recycled into recycled PET or rPET.

[0014] The 5-CMF formed by the action of hydrochloric acid on the cellulose is dissolved (or mixed if the 5-CMF is at a high enough temperature to be liquid) and preferentially mainly dissolved in the organic extraction liquid. The polyester, polyolefin, polyamide or elastane fibres are largely unaffected by the process and can be physically removed from the resulting liquids: aqueous hydrochloric acid dissolved with 5-CMF or small monosaccharides, and organic extraction liquid dissolved with 5-CMF, as the case may be. Thus, in the process of the invention, after step b. (for the first embodiment described above), it is preferred that all solid material, including the solid fibre material residue, is removed from the liquid phase. Here, the liquid phase comprises the aqueous phase comprising hydrochloric acid and the organic extraction liquid comprising 5-CMF. The non-liquid material removed by such a process comprises one or more of polyester fibre material, polyethylene fibre material, polypropylene fibre material, polyamide fibre material or elastane fibre material.

[0015] The 5-CMF formed by the action of hydrochloric acid on the solubilized / hydrolyzed cellulose is soluble in aqueous hydrochloric acid (and / or mixes when the melting point of 5-CMF is about 34° C.), but is difficult to isolate therefrom and may decompose in strong acid media. If an organic extraction solvent in which 5-CMF dissolves more readily than in aqueous hydrochloric acid is present during 5-CMF production (or after conversion of hydrolyzed cellulose to 5-CMF in another embodiment), and if the organic extraction solvent is selected to be poorly miscible with water, the 5-CMF formed during its formation may be relatively easily extracted from the aqueous hydrochloric acid phase. There are a variety of potentially suitable organic extraction solvents for this method. A high distribution coefficient (ratio of solubility of 5-CMF in the organic phase and the aqueous HCl phase) is desired to maximize 5-CMF extraction and minimize extraction solvent volume. The solvent should be selected based on cost, extraction coefficient, boiling point (preferably above 80° C.), stability, etc. Thus, in the method according to the invention, it is preferred that the organic extraction solvent comprises diisopropyl ether, ethyl acetate, pentane, hexane, heptane, octane, decane, dodecane, cyclohexane, benzene, chlorobenzene, toluene, xylene, chloroform, 1,2-dichloroethane, carbon tetrachloride, trichloromethane (chloroform), and mixtures thereof. A preferred class of extraction solvents for this purpose are halogenated aromatic solvents, which are aromatic compounds in which one or more halogen atoms are present. In this context, preferred halogenated aromatic solvents include chlorobenzene, dichlorobenzene (including o-, m-, and p-), trichlorobenzene (including 1,2,3-, 1,2,4-, 1,3,5-), fluorobenzene, difluorobenzene (including o-, m-, and p-), trifluorobenzene (including 1,2,3-, 1,2,4-, 1,3,5-), and mixed halobenzene compounds, such as CHFCl (o-, m-, and p-). Most preferred are organic extraction solvents comprising toluene, chlorobenzene, dichlorobenzene, fluorobenzene, difluorobenzene, 1,2-dichloroethane, or mixtures thereof.

[0016] In the method of the present invention, the main component is a textile fiber material containing cellulose. The most abundantly used materials of this kind are cotton and flax, jute, ramie, hemp, piña, and abaca. Thus, in the present invention, the cellulose fiber preferably comprises one or more of cotton, flax, jute, ramie, hemp, piña, and abaca, with cotton being the most preferred cellulose fiber material in the present invention. Obviously, in order to produce an attractive yield of 5-CMF, it is desirable for the blended fiber material to contain a significant amount of cellulose. Thus, in the present invention, the blended fiber material preferably comprises cellulose fiber material in an amount of 40-98% by weight, preferably 50-98% by weight. However, commercially available blended fiber materials contain functional amounts of fibers such as polyester, polyamide fibers, elastane fibers, or polyethylene or polypropylene. In this connection, in the present invention, the blended fiber material preferably comprises one or more of synthetic polyester fiber materials, polyethylene fiber materials, polypropylene fiber materials in an amount of 2-40% by weight, preferably 2-30% by weight. The most typical synthetic polyester fiber is preferably PET, and therefore is preferred as polyester in the present invention. The blended fabric can include woven fabric, nonwoven fabric, braided fabric, or blends thereof. An example of a blended woven fabric is, for example, a fabric used in making clothing, or a fabric for use in curtains and upholstery. An example of a nonwoven blended fabric is, for example, a fabric used to make cleaning wipes and disinfecting wipes.

[0017] The mixture of raw materials entering the reactor preferably has a moisture content of less than 10% by weight, more preferably less than 7% by weight, even more preferably less than 5% by weight, for example because otherwise the hydrochloric acid would be overly diluted.

[0018] The conversion of cellulose to 5-CMF with aqueous hydrochloric acid and its extraction in an organic extract can be carried out in a few hours. Therefore, in the method according to the invention, in step b. (first embodiment) and in step c. (second embodiment), the mixing of the reactor contents is preferably carried out for a time period between 0.5 hours and 12 hours, preferably between 1 hour and 10 hours. In the method according to the invention, the ratio of the mixed material to the aqueous solution of hydrochloric acid in step a is preferably between 1:200 and 1:5, preferably between 1:100 and 1:20.

[0019] The 5-CMF obtained in the organic extraction can be isolated and further processed into other chemically useful components, for example alkoxymethylfurfurals such as methoxymethylfurfural (MMF) and ethoxymethylfurfural (EMF), HMF, HMF acetate (AcMF) or methylfurfural (MF). This can be done using methods known per se by reacting 5-CMF with methanol, ethanol, water, acetic acid or hydrogen, respectively. Thus, in the present invention, it can be preferred to mix the organic extraction solvent containing 5-(chloromethyl)furfural (5-CMF) obtained by step c. (first embodiment) or step d. (second embodiment) with a liquid C1-C4-alkanol in a ratio of CMF:alkanol between 1:1 and 1:25, at a temperature between 10 and 40° C., to convert at least a portion of 5-(chloromethyl)furfural (5-CMF) into 5-RMF (R is a group as indicated above). Such methods are known, for example, from S. Bandibairanahalli Onkarappa, Chemistry Select, 2019, vol. 4, pp. 5540-5543. In particular, MMF and EMF are desired products, firstly, as intermediates for producing furandicarboxylic acids, and secondly, as components for fuel additives. In such conversions, the liquid C1-C4-alkanol is therefore preferred, comprising methanol or ethanol, preferably methanol. Similarly, HMF can be obtained by addition of water; MF can be obtained by CMF hydrogenation. In all these 5-CMF conversions, a catalyst can be added to promote the CMF conversion reaction.

[0020] Alternatively, 5-(chloromethyl)furfural (5-CMF) obtained in the solution in step c. (first embodiment) or step d. (second embodiment) can be isolated from the organic extraction solvent by evaporation of the solvent, optionally followed by distillation or recrystallization of the CMF, followed by subsequent conversion. The conversion of CMF to RMF, HMF, AMF or MF can be carried out in pure alcohol (to RMF), water (to HMF), or acetic acid (to AMF), or in the presence of an additional suitable solvent. EXAMPLES

[0021] Example 1 Materials and Equipment The reactions were carried out in small batch reactor tubes (volume: 9 ml): Ace glass high pressure tubes (product code: 8648-17) purchased from Sigma Aldrich and equipped with magnetic stirrers. These were heated in custom-made alumina heating blocks. Aqueous phase: 37% hydrochloric acid Organic phase: chlorobenzene (99.5%, Acros Organics, Examples 1 to 6), fluorobenzene (Examples 5 and 6) material: - Scraps of commercially available "jeans", approximately 98% cotton by weight (label), analysis results (Celignis Biomass Laboratory), average of three analyses, sugar 95.34%, total lignin 2.05%, ash 0.60% - PET fabric fiber: Overlocked PET yarn produced by Diamond Spun Garens - Scraps of a commercially available (yellow) polycotton sweater (80% cotton by weight, 20% polyester by weight (label)) - Scraps of commercially available socks (70% cotton, 28% polyester, 2% spandex (label))

[0022] procedure The reactor was charged with the desired amount of cotton-containing jeans fabric (10-25 mg, different amounts due to the difficulty of cutting small pieces of fabric), PET fibers (10-25 mg, varying for the same reason as the jeans pieces) were added to it, and 1 mL of hydrochloric acid was added. Finally, the organic phase (chlorobenzene, 3 mL) was added to the top. The reactor was closed and placed in an alumina block already preheated at the desired temperature while mixing. For the desired temperatures: reactions were carried out at 80°C, 90°C, and 100°C to study the effect of temperature. After 1 hour of reaction time, the vial was removed from the block and cooled in an ice bath for 15 minutes. The resulting aqueous liquid layer was dark in color and contained fibrous material. The upper organic liquid layer appeared clear and colorless. The organic layer (in this case, the top of the liquid mixture) was removed. Then, another 3 mL of organic phase was added. Subsequently, the reaction tube was placed back in the block preheated to the desired temperature for another hour. This was repeated until samples were obtained after 1, 2, 3, and 4 hours of reaction. This was performed at three different temperatures and each reaction was run in triplicate. This resulted in 3 x 3 x 4 = 36 samples.

[0023] The samples were analyzed by GC for the content of 5-(chloromethyl)furfural (5-CMF) without further workup by using a 1 mL sample of the organic fraction to which an external standard (0.1 mL dioxane in 0.9 mL toluene) was added.

[0024] result From the GC results, the molar yield of 5-(chloromethyl)furfural (5-CMF) in cotton was calculated, and the results are shown in Table 1 below.

[0025] [Table 1]

[0026] Results show cumulative molar yields of 5-(chloromethyl)furfural (5-CMF) in cotton ranging from about 40% to about 70% and visually intact appearing PET fibers. The PET fibers were dried and weighed, suggesting complete recovery of the plastic material. Subsequent glycolysis (with ethylene glycol) showed that the material was sufficiently PET that it could be nearly quantitatively recycled into BHET (bis(2-hydroxyethyl) terephthalate): 10-25 mg of PET yielded 12-30 mg of BHET (qualified and quantified by HPLC using dimethyl terephthalate as an external standard).

[0027] Example 2 Here, Example 1 was repeated, except that 40-50 mg of jeans fabric was used and 2 mL of hydrochloric acid solution (37% by weight) was used. The amount of chlorobenzene added to extract the samples was the same as in Example 1 (3 mL for each extraction). The timings for extracting the samples were 2 hours, 4 hours, and 6 hours. The temperatures selected for the experiment were 80°C and 90°C. As in Example 1, the experiment was carried out three times. The analysis was carried out in the same way. The results are shown in Table 2.

[0028] [Table 2]

[0029] Example 3 Here, Example 1 was repeated, except that the jeans fabric was stirred with 2 mL of 42% by weight hydrochloric acid solution and 3 mL of chlorobenzene at room temperature overnight. After 16 hours, the reactor was placed in an alumina block preheated at 80° C. The amount of chlorobenzene added to extract the samples was the same as in Example 1 (3 mL for extraction after 1 and 2 hours, 5 mL for extraction after 4, 6, and 8 hours). The timing of extracting the samples was after stirring overnight at 80° C., and after 1, 2, 4, 6, and 8 hours. As in Example 1, the experiment was carried out in triplicate. The analysis was carried out in the same way. The results are shown in Table 3.

[0030] [Table 3]

[0031] Example 4 Example 3 was repeated, except that three vials containing jeans fabric were stirred overnight at room temperature with 2 mL of 42% by weight hydrochloric acid solution and 3 mL of chlorobenzene, and an additional vial was stirred overnight at 30° C. Furthermore, the extraction time was shortened. After 16 hours, the reactor was placed in an alumina block preheated at 80° C. The amount of chlorobenzene added to extract the samples was the same as in Example 1 (3 mL for each extraction). For the first hour, the reaction mixture was extracted in the usual way every 20 minutes of reaction time. After 1 hour, the procedure was carried out as described above for a total reaction time of 5 hours. The results are shown in Table 4.

[0032] [Table 4]

[0033] Example 5 Example 1 was repeated, except that 50 mg of polycotton sweater fabric and 1 mL of hydrochloric acid solution (37% by weight) were used. The amount of chlorobenzene or fluorobenzene was 3 mL. The reaction was carried out at 90° C. for 3 hours. As in Example 1, the experiment was carried out in triplicate. The analysis was carried out in the same way. The results are shown in Table 5.

[0034] [Table 5]

[0035] Example 6 Example 5 was repeated, except that 55 mg of sock fabric and 1 mL of hydrochloric acid solution (37% by weight) were used. The amount of chlorobenzene or fluorobenzene was 3 mL. The reaction was carried out at 90° C. for 3 hours. As in Example 1, the experiment was carried out in triplicate. The analysis was carried out in the same way. The results are shown in Table 6.

[0036] [Table 6]

Claims

1. 1. A method for treating a blended fabric, the blended fabric comprising cellulose fiber material in an amount of 30-99% by weight and one or more of synthetic polyester fiber material, polyethylene fiber material, polypropylene fiber material, polyamide fiber material or elastane fiber material in an amount of 1-70% by weight, the method comprising: a. In the reactor: - the mixed fabric material contains 30-99% by weight of cellulose fiber material and 1-70% by weight of one or more of the synthetic polyester fiber material, polyethylene fiber material, polypropylene fiber material, polyamide fiber material or elastane fiber material; - Aqueous solution of hydrochloric acid with a concentration of 30% to 45% (by mass) an organic extraction solvent selected such that at 20° C., less than 1 g of the extraction solvent is dissolved in 100 ml of aqueous HCl, and the organic extraction solvent is further selected such that at 20° C., at least 10 g of 5-(chloromethyl)furfural can be dissolved in 100 ml of the organic extraction solvent; The process of preparing b. mixing the contents of the reactor at a temperature between 40° C. and 110° C. for at least 30 minutes, wherein the aqueous solution and the organic extractant are present in the reactor in a ratio of aqueous solution:organic extractant between 1:0.5 and 1:

10. c. Separating the organic extractant containing 5-(chloromethyl)furfural from the aqueous solution containing hydrochloric acid. A method for treating a mixed fabric material comprising:

2. 1. A method for treating a blended fabric, the blended fabric comprising cellulose fiber material in an amount of 30-99% by weight and one or more of synthetic polyester fiber material, polyethylene fiber material, polypropylene fiber material, polyamide fiber material or elastane fiber material in an amount of 1-70% by weight, the method comprising: a. In the reactor: - the mixed fabric material contains 30-99% by weight of cellulose fiber material and 1-70% by weight of one or more of the synthetic polyester fiber material, polyethylene fiber material, polypropylene fiber material, polyamide fiber material or elastane fiber material; - An aqueous solution of hydrochloric acid with a concentration of 36% to 51% (by mass) The process includes the steps of: at least partially hydrolyzing the cellulose of the cellulosic fibrous material for a period of at least 30 minutes and at a temperature of less than 40° C. to produce an aqueous hydrolysate and a solid fibrous residue. removing a solid fibrous residue from the product of c. mixing the aqueous hydrolyzate obtained by b. with an organic extraction solvent at a temperature between 50° C. and 110° C. for at least 30 minutes, wherein the aqueous solution and the organic extraction solvent are present in the reactor in a ratio of aqueous solution:organic extraction solvent between 1:0.5 and 1:10, and the organic extraction solvent is selected such that at 20° C., less than 1 g of the extraction solvent dissolves in 100 ml of the aqueous HCl solution, and the organic extraction solvent is further selected such that at 20° C., at least 10 g of 5-(chloromethyl)furfural can be dissolved in 100 ml of the organic extraction solvent. d. Separating the organic extractant containing 5-(chloromethyl)furfural from the aqueous solution containing hydrochloric acid. A method for treating a mixed fabric material comprising:

3. 2. The method of claim 1, wherein after step b. all solid matter, including solid fiber material residue, is removed from the liquid phase.

4. 4. The method according to claim 1 or 3, wherein in step b., mixing the reactor contents is carried out for a time between 0.5 hours and 12 hours, preferably between 1 hour and 10 hours.

5. 3. The method of claim 2, wherein in step c., mixing the reactor contents is carried out for a time between 0.5 hours and 12 hours, preferably between 1 hour and 10 hours.

6. 4. The method of claim 2 or 3, wherein the non-liquid substance to be removed comprises one or more of a polyester fiber material, a polyethylene fiber material, a polypropylene fiber material, a polyamide fiber material, or an elastane fiber material.

7. 7. The method of any one of claims 1 to 6, wherein the organic extraction solvent comprises diisopropyl ether, ethyl acetate, pentane, hexane, heptane, octane, decane, dodecane, cyclohexane, benzene, toluene, xylene, 1,2-dichloroethane, carbon tetrachloride, trichloromethane, halogenated aromatic solvents, and mixtures thereof.

8. 8. The method of claim 7, wherein the organic extraction solvent comprises toluene, a halogenated aromatic solvent, 1,2-dichloroethane, or a mixture thereof.

9. 9. The method of claim 8, wherein the halogenated aromatic solvent comprises chlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, fluorobenzene, o-difluorobenzene, m-difluorobenzene, p-difluorobenzene, 1,2,3-trifluorobenzene, 1,2,4-trifluorobenzene, 1,3,5-trifluorobenzene, mixed halobenzene compounds, and mixtures thereof.

10. 10. The method of claim 1, wherein the cellulosic fibers comprise cotton.

11. 11. The method according to any one of claims 1 to 10, wherein the ratio of mixed dough material to aqueous solution of hydrochloric acid in a. is between 1:200 and 1:5, preferably between 1:100 and 1:

20.

12. The method according to any one of the preceding claims, wherein the mixed fabric comprises cellulosic fibre material in an amount of 40-98% by weight, preferably 50-98% by weight.

13. 13. The method according to any one of claims 1 to 12, wherein the mixed textile material comprises 2 to 40% by weight, preferably 2 to 30% by weight, of one or more of synthetic polyester fibre materials, polyethylene fibre materials, polypropylene fibre materials, the synthetic polyester being preferably PET.

14. 14. The method according to any one of claims 1 to 13, wherein the 5-(chloromethyl)furfural obtained in the solution of the last claimed step is isolated from the organic extraction solvent.

15. 15. The method of any one of claims 1 to 14, wherein the composite textile material comprises a woven material, a nonwoven material, a braided material, or a mixture thereof.

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