Process for converting mixed fabric material comprising cellulosic fibre material into 5-(chloromethyl)furfural

Abstract

A process for converting a composition comprising mixed fabric material in particulate form, said mixed fabric material comprising cellulosic fibre material in an amount of 50 to 99 % by weight and further comprising 1-50 % by weight of one or more of man-made fibre material such as PET, into 5- (chloromethyl)furfural (CMF) with aqueous hydrochloric acid and multiple extractions using an organic extraction solvent.

Description

[0001] PROCESS FOR CONVERTING MIXED FABRIC MATERIAL COMPRISING CELLULOSIC FIBRE MATERIAL INTO 5-(CHLOROMETHYL)FURFURAL

[0002] Introduction

[0003] The present invention relates to a process for treating fabric material, which fabric material comprises cellulosic fibre material (e.g. from cotton, flax, jute, ramie, hemp, Pina and Abaca) and non-cellulosic, manmade polymer fibre material, such as polyester and / or polyolefins (polyethylene or polypropylene), polyamide fibre material or elastane fibre material, with the aim to obtain 5-(chloromethyl)furfural (CMF). So-obtained CMF may be further processed e.g. into 5-(hydroxymethyl)furfural, 5-alkoxymethylfurfural, 5- (acetoxymethyl)furfural, methylfurfural or isolated as CMF. The treatment relates to hydrolysing at least part of the cellulose fibre material (e.g. cotton) that is present in the mixed fabric material with concentrated hydrochloric acid, and converting the hydrolysed cellulose into 5-(chloromethyl)furfural (CMF) in a CSTR and subsequent multiple extraction steps.

[0004] Background of the invention

[0005] The chemical compound 5-(chloromethyl)furfural (hereinafter: CMF) is a promising compound, for two reasons: it can be formed from treating carbohydrate-containing biomass (and as such it is a compound from a renewable source) with hydrochloric acid, and it can be converted in several other compounds such as HMF (hydroxymethylfurfural) and MMF (methoxymethylfurfural) that can be used in chemical industry easily. Hence, it is a bio-sourceable material providing options to produce other chemical compounds.

[0006] Patent application WO2019 / 149843 discloses a process in which solid lignocellulosic material such as woodchips is treated with strong hydrochloric acid. Such lignocellulosic material contains as main fractions hemicellulose, cellulose and lignin. The process of the referred patent application subjects the substantially dried lignocellulosic material first to hydrochloric acid in a concentration of 15 to 40% at room temperature, to hydrolyse and remove from the lignocellulosic material the hemicellulose, which thereafter removed from the reactor. Subsequently, the remaining material is subjected to hydrochloric acid of 40-51% strength at room temperature, to hydrolyse and remove from the reactor the cellulose fraction, leaving behind the solid lignin residue in the reactor. The process continues by subjecting the hydrolysate of cellulose obtained (which next to the carbohydrates like glucose and glucose oligomers) still contains hydrochloric acid) to heating, to yield 5-(chloromethyl)furfural (CMF). The so-obtained CMF can be extracted with a solvent. In this process, hydrochloric acid is required of a very high concentration (40- 51%) which is disadvantageous from a general processing point of view, but such is due to cellulose being resistant to hydrolysis. Similar to the above reference, WO2014 / 066746 discloses a process for producing 5-(chloromethyl)-furfural by acid-catalysed conversion of biomass.

[0007] M. Mascal et al (Angew. Chem. Int. Ed. 2008. 47, 1-4) disclose that microcrystalline cellulose can be converted into CM F with conversion degrees of 80%, when in the presence of 5% lithium chloride. CMF was the main product (71%) with other products being present in substantial amounts as well. Extraction duration is 18 hours. Lithium chloride is known to disrupt the crystallinity of cellulosic materials, thus enhancing the hydrolysis of it. Whilst the conversion is acceptable, the long duration required for it is not acceptable for a commercial operation. Also the required presence of lithium chloride, whilst acceptable for a research aim, is not attractive in a commercial operation, as it is another compound that needs to be recovered from the aqueous phase for purification and reuse.

[0008] Cellulose is also present as cellulosic fibres in fabrics such as textile for e.g. clothing. Cellulosic fibre material such as cotton has many uses, e.g. in fabric for textile for use in clothing. Such clothing has a finite life, e.g. due to wear. The end-of-life of cotton-containing clothing, optionally after recycling to suit other uses, often means ending up in land-fill or waste incineration with or without energy recovery. More and more, land-fill as a destination of clothing after use is seen as undesired, and recycling is investigated. Recycling high-value cotton fibre into new cellulose-containing fibre for use in textile for clothing is often not possible, largely due to cotton (and other cellulosic fibres) being used in textile mixed with other fibres (in varying amounts), such as polyester, to give the textile the desired properties (e.g. strength, costeffectiveness, ease of manufacture and others). Textiles containing such mixture of cellulosic and non- cellulosic fibres are hitherto hard or impossible to recycle into a valuable product. Even clothing that is stated to be 100% cotton, often has stitching of polyester yarn, and this also is a "mixed fibre textile". Apart from ending up in land-fill or incineration facilities, such mixed fibre textiles are used to make e.g. rags. That is re-using as textile, but it is down-cycling rather than recycling, as rags (e.g. for industrial cleaning) are a low-value product, and there is a limited use for such products.

[0009] Cellulosic fibre is also used as an ingredient in medical wipes, e.g. for cleaning and / or disinfection, which find use in e.g. hospitals, care institutions, and centres for medical services such as vaccination and testing for infectious diseases. To minimize risk of contamination or infection for patients and personnel, such medical wipes are used abundantly, and have a single use. Clearly, this leads to a large amount of waste material of such textile. All sorts of material are used for medical wipes, but a large selection contains cotton and a non-cellulosic, man-made fibre such as polyester. Re-using is virtually impossible or undesired, and the material is usually incinerated after being discarded.

[0010] Hence, there is a desire for being able to turn discarded clothing or fabric such as medical wipes made of fabric that contains both cotton or other cellulosic fibre as well as a non-cellulosic fibre such as polyester (typically PET) into more valuable products than into rags, to serve as an alternative to being incinerated or used as land-fill. Likewise, there is a need for processes that allow chemical building blocks to be made from sources which are not fully based on fossil-carbon sources. Furthermore, there is a desire for a process to produce 5-(chloromethyl)furfural (CMF) or solution containing CMF which does not have the disadvantages that the prior art processes discussed above have, and preferably a process with which such can be carried out in a continuous way.

[0011] Summary of the invention

[0012] It has now been found objective that the above may be achieved, at least in part, by a process for preparing 5-(chloromethyl)furfural from mixed fabric material in particulate form, said mixed fabric material comprising cellulosic fibre material in an amount of 50 to 99 % by weight and further comprising 1-50 % by weight of one or more of man-made polyester fibre material, polyethylene fibre material, polypropylene fibre material, polyamide fibre material, or elastane fibre material, said process comprising the steps of:

[0013] I. providing to a CSTR: a feed composition comprising said mixed fabric material in particulate form, an aqueous feed comprising hydrochloric acid at a concentration HCI of 18 - 45%, a feed comprising an organic extraction solvent,

[0014] II. reacting said mixture at a temperature of between 60 and 120°C and having an average residence time in the CSTR of between 10 minutes to 3 hours and producing an effluent,

[0015] III. feeding the effluent of the CSTR to a first continuous extraction device producing: a first organic extraction fraction comprising organic extraction solvent and 5- (chloromethyl)furfural, an aqueous fraction comprising hydrochloric acid, said continuous extraction device operating at a temperature which is between 5 and 25°C higher than the temperature in the CSTR in step II., and having an average residence time in the continuous extraction device of between 10 minutes to 2 hours,

[0016] IV. feeding the aqueous fraction obtained in step III. to a second continuous extraction device, to which second continuous extraction device is also fed organic extraction solvent, said second continuous extraction device producing: a second organic extraction fraction comprising organic extraction solvent and 5- (chloromethyl)furfural, an aqueous fraction comprising hydrochloric acid, said second continuous extraction device is operating at a temperature which is between 5 and 25°C higher than the operating temperature of the first continuous extraction device, in step III. and which second continuous extraction device has an average residence time,

[0017] V. purifying and / or further reacting the 5-(chloromethyl)furfural present in the first and / or second organic extraction fraction, wherein the organic extraction solvent is chosen such that at 20°C less than 2 g of extraction solvent dissolves in 100 ml of the aqueous HCI solution, and wherein the organic extraction solvent is further chosen such that at 20°C at least 5 g of 5-(chloromethyl)furfural can be dissolved in 100 ml of the organic extraction solvent.

[0018] Detailed description of the invention

[0019] Part of the invention resides in the fact that cellulose in a mix of fibres containing both cellulose and manmade polyester, polyolefins, polyamide fibre and elastane fibre, may be used as a source to yield 5- (chloromethyl)furfural (CMF) by hydrolysis of the cellulose followed by conversion of glucose / glucose oligomers into CMF by the action of hydrochloric acid, extraction of the CMF with an organic extractant, whilst the man-made polyester fibres, polyolefin fibres, polyamide fibres and elastane fibre are left largely or completely physically intact. The man-made polyester, polyolefins, polyamide and elastane fibre are resistant to the action of hydrochloric acid in this process. Another part of the invention resides in the fact that the process now claimed allows for continuous processing, which is attractive commercially.

[0020] As set out above, so far mixed fibre blends of e.g. cotton with one or more of polyester, polyolefins, polyamide, or elastane after usage for what the fibre blends were designed for (clothing, cleaning, protection, domestic use like in curtains, etcetera) not be put to much other use than for making rags or for incineration. It was surprisingly found that by the above process, a mixed fibre blend of cotton and one or more of polyester fibres (e.g. PET), polyolefin fibres, polyamide fibres, or elastane fibres was suitable as a source to produce a useful chemical intermediate compound 5-(chloromethyl)furfural. Even more surprising and beneficial, the process according to the present invention allows for the residual man-made polymer material being part of thye mixed fabric material, such as PET, to be mechanically or chemically recycled to recycled PET or rPET.

[0021] Since the man-made fibres being part of the mixed fabric material of the feed in the now claimed process is left substantially intact (or at least it is not broken down and dissolved all) the man-made fibre part of the mixed fabric material remains as solid in the process. It is desired to remove such from the product streams at some point. Hence, in the present invention it is preferred that the one or more of man-made polyester fibre material, polyethylene fibre material, polypropylene fibre material, polyamide fibre material, or elastane fibre material (or the remains thereof) is separated from the liquid effluents of the CSTR after stage II. and prior to stage III or are separated from the liquid effluents of the first continuous extraction device or from the liquid effluents of the second continuous extraction device.

[0022] It is known that cellulose is fairly resistant to hydrolysis with hydrochloric acid. Hence, the conversion to CMF in good yields is a challenge. Without wishing to be bound by theory, it seems that polymeric sources of glucose (cellulose) have different crystallinity within it: some areas are more difficult to hydrolyze than others, and the accessibility of these different regions to the acid is also not the same across all the material at hand.

[0023] Surprisingly, it was found that if one starts with low or moderate temperatures to hydrolyze the most accessible and lower crystallinity areas, and one removes most or all of the CMF formed (i.e. reaction and extraction), and thereafter applies a second reaction / extraction at higher temperatures, preferably at shorter times, one can hydrolyze the apparently more recalcitrant and less accessible parts of the cellulose. This is especially relevant for cellulose. Starting the first hydrolysis step at a very high temperature is not desired, as it may lead to decomposition of hydrolysed glycose and oligomers also present in the aqueous solution, which in turn may lead to formation of brown / black insoluble deposits (believed to be humins). Also, to avoid CMF to be degraded or hydrolysed, such is preferably removed to a substantial degree (e.g. at least 90%) prior to adding a further portion of aqueous hydrochloric acid. The present invention yields CMF dissolved in an extraction solvent, which is considered to achieving the aim. The CMF may be isolated therefrom, but due to its instability it is preferably converted first into other compounds, like 5-hydroxymethylfurfural, 5-methoxymethylfurfural, or 5-ethoxymethylfurfural.

[0024] Hence, the process of the present invention is characterized by: reacting the mixed textile fibre particles comprising cellulose and man-made fibres with aqueous hydrochloric acid at a temperature Tl, removal of a substantial part of the CMF formed by extracting with a suitable extraction solvent at T2, followed by a next addition of organic extraction solvent and reacting such at a temperature T3, and extract a next portion of CMF, wherein T3 is higher than T2, and T2 is higher than Tl.

[0025] Also, in order to minimise the amount of humins formed, it is preferred that the reaction at T2 is conducted for a shorter duration than the one at Tl, and T3 for a shorter duration than Tl.

[0026] During extraction step III. and IV. separation is achieved, but also reaction (production of CMF). Hence, in the present invention, it is preferred that the average residence time of the first continuous extraction device in step III. is the same or shorter than the average residence time in the CSTR, preferably at least 10% shorter, more preferably at least 20% shorter. Likewise, it is preferred that the average residence time of the second continuous extraction device in step IV. has an average residence time which is the same or shorter than the average residence time of the first extraction device, preferably at least 10% shorter, more preferably at least 20% shorter. Even more preferred, both the average residence time of the first continuous extraction device in step III. is the same or shorter than the average residence time in the CSTR, as well as that the average residence time of the second continuous extraction device in step IV. has an average residence time which is the same or shorter than the average residence time of the first extraction device.

[0027] It was found that the process of the present invention can be carried out easily with an aqueous hydrochloric acid solution of about 37°% wt, as such is a commercial strength hydrochloric acid. However, the processes according to the present invention can also be carried out with an aqueous hydrochloric acid composition which is more concentrated. Nevertheless, lower concentrations are preferred here, as such is cheaper, and easier to manage. Hence, in the present invention it is preferred that the aqueous feed comprising hydrochloric acid in I. has a concentration HCI of at 19-40 wt%, preferably 30-39 wt%, more preferably 35-39 wt%. In this connection, aqueous hydrochloric acid at a concentration of around 20 wt% may be preferred in some cases, as such is the concentration of the azeotrope of hydrochloric acid and water. Such azeotrope is easily formed in recovery and / or regenerating the aqueous solution that is left after several extractions. Hence, it is preferred in the presently claimed process that the hydrochloric acid has a concentration found at the azeotrope of hydrochloric acid and water.

[0028] As to the amount of aqueous hydrochloric acid to be used in the present invention, it is preferred that the mixed fabric material in particulate form in I. is mixed with the aqueous feed comprising hydrochloric acid in a weight ratio of mixed fabric material in particulate form : aqueous feed comprising hydrochloric acid of between 1 : 2 and 1 : 50, preferably between 1 : 5 and 1 : 30.

[0029] In the presently claimed process the reaction of the aqueous hydrochloric acid on the cellulose in the presence of the organic extraction solvent is carried out at a temperature of between 60 and 120°C. It is preferred that the temperature of the reaction in step II. of said mixture is between 70 and 110°C, preferably between 75 and 100°C.

[0030] The CMF that is formed by the action of hydrochloric acid on the mixed fabric material in particulate form does dissolve (and or mix, as the melting point of CMF is about 34°C) in the aqueous hydrochloric acid, but is difficult to isolate therefrom and it may also decompose in the strong acid medium. If an organic extraction solvent is present during the CMF production, in which the CMF dissolves easier than in the aqueous hydrochloric acid, and if the organic extraction solvent is selected such that it does not mix well with water or an aqueous liquid, the CMF formed can be extracted from the aqueous hydrochloric acid phase relatively easily during its formation. Hence, in the present invention the organic extraction solvent is chosen such that at 20°C less than 2 g (preferably less than 1 g) of extraction solvent dissolves in 100 ml of the aqueous HCI solution, and wherein the organic extraction solvent is further chosen such that at 20°C at least 5 g (preferably at least 10 g) of 5-(chloromethyl)furfural can be dissolved in 100 ml of the organic extraction solvent.

[0031] There is a range of potentially suitable organic extraction solvents for this process. A high distribution coefficient (the ratio of the solubility of CMF in the organic phase and the aqueous HCI phase) is desired to maximize CMF extraction and to minimize extraction solvent volume. The solvent should be selected on the basis of price, extraction coefficient, boiling point (preferably above 80°C) stability, etc. Hence, in the process according to the present invention, it is preferred that the organic extraction solvent comprises a halogenated aromatic solvent, diisopropyl ether, ethyl acetate, pentane, hexane, heptane, octane, decane, dodecane, cyclohexane, benzene, toluene, xylene, chloroform, 1,2-dichloroethane, carbon tetrachloride, trichloromethane, and mixtures thereof. Preferably, in case the organic extraction solvent is a halogenated aromatic solvent such is preferably selected from the group consisting of: mono-chlorobenzene, o- dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, 1,2,4-trichlorobenzene, mono-fluorobenzene, o- difluorobenzene, m-difluorobenzene, p-diflurorobenzene, 1,2,4-trifluorobenzene, l,3-dichloro-2- fluorobenzene, fluorotoluene, chlorotoluene, and mixtures thereof, with fluorobenzene being most preferred.

[0032] In the present invention, it is preferred that in step I. the volume ratio organic extraction solvent : aqueous feed comprising hydrochloric acid is between 0.5 : 1 and 20 : 1, preferably between 1 : 1 and 10 : 1, and / or wherein in step III. the volume ratio organic extraction solvent : aqueous fraction comprising hydrochloric acid is between 0.5 : 1 and 20 : 1, preferably between 1 : 1 and 10 : 1.

[0033] In the present invention, it was found that yields in CMF are good if there are multiple extraction stages. Without wishing to be bound by theory, it is believed that this drives the reaction further. A tool suitable to carry out the extraction is one in which reactive extraction can take place. Hence, it is preferred that that the first continuous extraction device and / or second continuous extraction device is a column for reactive extraction.

[0034] Also preferred for a process that is carried out in a continuous fashion, is capture and regeneration of the hydrochloric acid involved. Hence, in the process according to the present invention it is preferred that the aqueous fraction comprising hydrochloric acid produced by the first continuous extraction device and / or produced by the second continuous extraction device is subjected to purification to yield purified aqueous hydrochloric acid.

[0035] In the present process, a key component is the mixed fabric fibre material containing cellulose. The most abundantly used materials of that kind are cotton and flax, jute, ramie, hemp, Pina and Abaca. Hence, in the present invention it is preferred that the cellulosic fibre comprises one or more of cotton, flax, jute, ramie, hemp, Pina and Abaca, with cotton being most preferred as cellulosic fibre material in the present invention. Clearly, in order to yield attractive yields of CMF it is desired that the mixed fibre material contains a substantial amount of cellulose. In the present invention, it is preferred that the mixed fabric material in particulate form comprises cellulosic fibre material in an amount of 40 to 98% by weight, preferably 50 to 98% by weight. Additionally, it is preferred that the mixed fabric material comprises 2 - 40% by weight of one or more of man-made polyester fibre material, polyethylene fibre material, polypropylene fibre material, preferably 2 -30% by weight, and wherein the man-made polyester is preferably PET. The mixed fabric material can comprise woven material, non-woven material, braided material or mixtures thereof. An example of woven mixed textile material are textiles such as are used for e.g. the manufacture of clothing, or textiles for use for e.g. curtains and upholstery. An example of non-woven mixed fabric materials are e.g. those used for making cleaning and disinfection wipes. The mixture of fabric material entered into the reactor preferably has a moisture content of below 10% by weight, more preferably below 7% by weight, even more preferably below 5% by weight, as e.g. otherwise the hydrochloric acid is too much diluted.

[0036] The CMF obtained in the organic extraction liquid can be isolated or can be processed further in other chemical useful components, such as to alkoxymethyl furfural, e.g. methoxymethyl furfural (MMF) and ethoxymethyl furfural (EMF), to HMF, HMF acetate (AcMF) or to methylfurfural (MF). This can be done with processes which are known as such by reacting CMF with methanol, ethanol, water, acetic acid or hydrogen, respectively. Hence, in the present invention it may be preferred that the organic extraction solvent comprising 5-(chloromethyl)furfural (CMF) obtained stage V is mixed with liquid Cl-C4-alkanol in a ratio CMF : alkanol of between 1 : 1 and 1 : 25 and subjected to a temperature of between 10 and 40°C to convert at least part of the 5-(chloromethyl)furfural (CMF) into RMF (R being the groups as set out above). Such processes are e.g. known from S. Bandibairanahalli Onkarappa, Chemistry Select, 2019, 4, 5540-5543. In particular MMF and EMF are desired products, the first as an intermediate to produce furan dicarboxylic acid, and the second as component for fuel additives. Hence, in such conversion it is preferred that the liquid Cl-C4-alkanol comprises methanol or ethanol, and preferably is methanol. In a similar way, HMF can be obtained by addition of water; MF can be obtained by CMF hydrogenation. In all these CMF conversions, a catalyst can be added to accelerate the CMF conversion reaction.

[0037] Hence, it is preferred in the present invention that in step V. the 5-(chloromethyl)furfural present in the first and / or second organic extraction fraction obtained in step III. and / or step IV. is converted into 5- hydroxymethylfurfural, 5-methoxymethylfurfural, or 5-ethoxymethylfurfural, or mixtures thereof.

[0038] Alternatively, the 5-(chloromethyl)furfural (CMF) obtained in solution in stage V. can be isolated from the organic extraction solvent . By evaporation of the solvent followed by subsequent conversion, optionally after distillation or re-crystallization of the CMF. Conversion of CMF to RMF, HMF, AMF or MF can be performed in neat alcohol (to RMF), water (to HMF) or acetic acid (to AMF) or in the presence of an additional suitable solvent.

[0039] EXAMPLES

[0040] Example 1

[0041] Materials and equipment

[0042] The reaction was performed in small batch reactor tubes (volume: 9 ml): Ace glass high pressure tubes purchased in Sigma Aldrich (product code: 8648-17), and were equipped with magnetic stirrers. These were heated in alumina heating blocks custom made.

[0043] Aqueous phase: 37%wt hydrochloric acid

[0044] Organic phase: Chlorobenzene (99.5%, Acros Organics, examples 1-6), fluorobenzene (examples 5, 6) Fabric:

[0045] - pieces of commercial "jeans", ~98%wt. cotton (label), Analytical results (Celignis Biomass Laboratory), average of triplo analysis, sugar 95.34%, total lignin 2.05%, ash 0.60%.

[0046] - PET textile fibre: overlock PET yarn produced by Diamond Spun Garens.

[0047] - pieces of commercial (yellow) polycotton sweater (80%wt cotton, 20%wt polyester (label).

[0048] - pieces of commercial socks (70%wt cotton, 28%wt polyester, 2%wt Spandex (label)).

[0049] Procedure

[0050] The reactor was loaded with the desired amount of cotton-containing jeans fabric (10-25 mg, the amount differed due to difficulty cutting small pieces of fabric), and PET fibers (10-25 mg, range for the same reason as for the pieces of jeans) were added to that, and further 1 mL of hydrochloric acid was added. Lastly the organic phase (chlorobenzene, 3 mL) was added on top of it. The reactor was closed and placed inside the alumina block already pre-heated at the desired temperature, under mixing. As to the desired temperature: reactions were carried out at 80, 90 and 100 °C to study the influence of the temperature. After 1 hour of reaction time, the vials were taken out of the block, cooled down in an ice bath for 15 minutes. The resulting aqueous liquid layer was darkly coloured, and contained fibrous material. The layer of organic liquid on top appeared clear and colourless. The organic layer (in this case on top of the liquid mixture) was removed . Thereafter, a further 3mL of organic phase was added. Subsequently, the reaction tube was put back in the pre-heated block at the desired temperature for another hour. This was repeated until samples were obtained after 1 hour, 2 hours, 3 hours and 4 hours of reaction. This was performed for three different temperatures, and each reaction was carried out three times. This gave 3x3x4 = 36 samples.

[0051] The samples were analysed by GC as to the content of 5-(chloromethyl)furfural (CMF) without further work-up, by using a 1 mL sample of the organic fraction with added thereto an external standard (0.1 mL dioxane in 0.9 mL toluene).

[0052] Results

[0053] From the GC results the molar yield of 5-(chloromethyl)furfural (CMF) on cotton was calculated. The results are set out in table 1 below.

[0054] Table 1: Molar yield of CMF on cotton of example 1

[0055] The results show a cumulative molar yield of 5-(chloromethyl)furfural (CMF) on cotton of between about 40 and 70%, and PET fibres which appeared visually intact. The PET fibers were dried and weighed which indicated full recovery of the plastic material. Subsequently, glycolysis (with ethylene glycol) showed that the material was indeed PET and could be recycled to near quantitatively to BHET (bis(2- hydroxyethyl)terephthalate): from the 10-25 mg PET, 12-30 mg BHET was obtained (qualification and quantification by HPLC using dimethylterephthalate as an external standard.

[0056] Example 2 Example 1 was repeated, except that now 40-50 mg of jeans fabric was used, and 2 mL of hydrochloric acid solution (37% wt) was used. The amount of chlorobenzene added for extracting the samples was the same as in example 1 (3mL for each extraction). Timing for extracting the samples was after 2 hours, after 4 hours, and after 6 hours. Temperatures selected for the trails were 80 and 90°C. Like for example 1, trials were carried out in triplo. Analysis was done in the same way. The results are set out in table 2.

[0057] Table 2: Cumulative molar yield of CMF on fabric of example 2

[0058] Example 3

[0059] Example 1 was repeated, except that now the jeans fabric was stirred at room temperature overnight with 2 mL of 42 wt% hydrochloric acid solution and 3 mL of chlorobenzene. After 16 h, the reactors were placed in the pre-heated alumina blocks at 80 °C. The amount of chlorobenzene added for extracting the samples was the same as in example 1 (3mL for extraction after 1 and 2 h, 5 mL for extraction after 4, 6, and 8 h). Timing for extracting the samples was after stirring overnight, and after 1 hour, 2 hours, after 4 hours, after 6 hours, and after 8 hours at 80 °C. Like for example 1, trials were carried out in triplo. Analysis was done in the same way. The results are set out in table 3.

[0060] Table 3: Molar yield of CMF on fabric of example 3

[0061] Example 4 Example 3 was repeated, except that now 3 vials with jeans fabric were stirred overnight with 2 mL of 42 wt% hydrochloric acid solution and 3 mL of chlorobenzene at room temperature while an additional vial was stirred overnight at 30 °C. In addition, the extraction times were shortened. After 16 h, the reactors were placed in the pre-heated alumina blocks at 80 °C. The amount of chlorobenzene added for extracting the samples was the same as in example 1 (3mL for each extraction). For the first hour, every 20 mins reactions time the reactions mixture was extracted in the usual manner. After 1 h, the procedure was executed as described above until 5 hours of total reaction time. The results are set out in table 4.

[0062] Table 4: Molar yield of CMF on jeans fabric of example 4. R#04 was heated overnight at 30 °C.

[0063] Example 5

[0064] Example 1 was repeated, except that now 50 mg of a polycotton sweater fabric and 1 mL of hydrochloric acid solution (37% wt) was used. The amount of chlorobenzene or fluorobenzene was 3 mL. The reaction was run at 90 °C for 3 h. Like for example 1, trials were carried out in triplo. Analysis was done in the same way. The results are set out in table 5.

[0065] Table 5: Molar yield of CMF on mixed polycotton fabric (sweater) of example 5. Example 6

[0066] Example 5 was repeated, except that now 55 mg of socks fabric and 1 mL of hydrochloric acid solution (37% wt) was used. The amount of chlorobenzene or fluorobenzene was 3 mL. The reaction was run at 90 °C for 3 h. Like for example 1, trials were carried out in triplo. Analysis was done in the same way. The results are set out in table 6.

[0067] Table 6: Molar yield of CMF on mixed polycotton fabric (socks) of example 6.

[0068] Example 7

[0069] For example 6, a series of experiments using cellulose as starting material was subjected to batch experiments, in which the cellulose was subjected to aqueous hydrochloric acid (37%), using different reaction temperatures and times such temperature was maintained, as is set out in table 7 below.

[0070] In table 7:

[0071] "comp." means comparative experiment, i.e. not according to the invention

[0072] "inv." means experiment according to the present invention

[0073] Whenever there are multiple reaction temperatures mentioned in table 1, there is in the next column the duration for each of those temperatures. See further under procedure all other experiments.

[0074] Some experiments were carried out twice with the same time / temperature combinations, as duplicate.

[0075] Procedure for all experiments:

[0076] Setup: 9mL Ace glass high pressure tubes purchased in Sigma Aldrich heated in alumina heating blocks custom made. Reactions in this closed system were always performed under stirring (lOOOrpm) by magnetic stirrer. Aqueous phase: ImL HCI 37%wt + 30 mg of starting material (cellulose) Organic phase : 3mL fluorobenzene, 99%, Acros Organics

[0077] Procedure experiments 14-02, 25-03, 25-04, 25-06, 25-07:

[0078] Experimental: Load the reactor with desired amount of cellulose (MC or fibers), then add HCI 37% (1 mL) and the organic phase (Fluorobenzene, 3mL) on top of it. Close the reactor and locate it inside the alumina block already pre-heated at the desired temperature. After reaching the desired reaction time, the reactor is brought to room temperature and the organic phase is separated (using a glass pipette) from the aqueous layer. Then the work-up takes place (work-up described in another section, down below).

[0079] Procedure all other experiments:

[0080] Experimental: Load the reactor with desired amount of cellulose (MC or fibers), then add HCI 37% (1 mL) and the organic phase (Fluorobenzene, 3mL) on top of it. Close the reactor and locate it inside the alumina block already pre-heated at the desired temperature. After reaching the first block of time (0.5h., 0.75h., lh., or 1.5h., depending on the experiment), the reactor is brought to room temperature and the organic phase is collected (using a glass pipette) from the aqueous layer. Then, additional 3 mL of organic phase is added to the reactor and the reactor is placed back into the alumina heating block at the desired (new) temperature (80, 90, or 100°C, depending on the experiment). After reaching time completion of this new time block, the same procedure explained before is repeated in which the reactor is brought to room temperature, the organic phase is separated, new organic phase (3 mL) is added to it and the reactor is placed back into the alumina block to continue reaction at the desired temperature. When the time / temperature-blocks are completed (usually 2 or 3 blocks of times and temperatures), the organic phase is collected and the work-up takes place.

[0081] For all experiments:

[0082] Work-up: Wash the aqueous phase using 3mL of additional organic phase. Stir for 1 h. at room temperature and then collect the organic phase. Repeat this washing step a total amount of 2 times. Then collect and combine all the organic phases together.

[0083] Sample preparation: ImL organic fraction + O.lmL Internal Standard (Dioxane in Toluene) Analysis: Performed by GC

[0084] Table 7: Cellulose as starting material

Claims

CLAIMS1. Process for preparing 5-(chloromethyl)furfural from mixed fabric material in particulate form, said mixed fabric material comprising cellulosic fibre material in an amount of 50 to 99 % by weight and further comprising 1-50 % by weight of one or more of man-made polyester fibre material, polyethylene fibre material, polypropylene fibre material, polyamide fibre material, or elastane fibre material, said process comprising the steps of:I. providing to a CSTR: feed composition comprising said mixed fabric material in particulate form, an aqueous feed comprising hydrochloric acid at a concentration HCI of 18 - 45%, a feed comprising an organic extraction solvent,II. reacting said mixture at a temperature of between 60 and 120°C and having an average residence time in the CSTR of between 10 minutes to 3 hours and producing an effluent,III. feeding the effluent of the CSTR to a first continuous extraction device producing: a first organic extraction fraction comprising organic extraction solvent and 5- (chloromethyl)furfural, an aqueous fraction comprising hydrochloric acid, said continuous extraction device operating at a temperature which is between 5 and 25°C higher than the temperature in the CSTR in step II., and having an average residence time in the continuous extraction device of between 10 minutes to 2 hours,IV. feeding the aqueous fraction obtained in step III. to a second continuous extraction device, to which second continuous extraction device is also fed organic extraction solvent, said second continuous extraction device producing: a second organic extraction fraction comprising organic extraction solvent and 5-(chloromethyl)furfural, an aqueous fraction comprising hydrochloric acid, said second continuous extraction device is operating at a temperature which is between 5 and 25°C higher than the operating temperature of the first continuous extraction device, in step III. and which second continuous extraction device has an average residence time,V. purifying and / or further reacting the 5-(chloromethyl)furfural present in the first and / or second organic extraction fraction, wherein the organic extraction solvent is chosen such that at 20°C less than 2 g of extraction solvent dissolves in 100 ml of the aqueous HCI solution, and wherein the organic extraction solvent is further chosen such that at 20°C at least 5 g of 5-(chloromethyl)furfural can be dissolved in 100 ml of the organic extraction solvent.

2. Process according to claim 1, wherein the aqueous feed comprising hydrochloric acid in I. has a concentration HCI of at 19-40 wt%, preferably 30-39 wt%, more preferably 35-39 wt%.

3. Process according to claim 1 or 2, wherein the one or more of man-made polyester fibre material, polyethylene fibre material, polypropylene fibre material, polyamide fibre material, or elastane fibre material are separated from the liquid effluents of the CSTR after stage II. and prior to stage III or are separated from the liquid effluents of the first continuous extraction device or from the liquid effluents of the second continuous extraction device.

4. Process according to any of the preceding claims, wherein the mixed fabric material in particulate form in I. are mixed with the aqueous feed comprising hydrochloric acid in a weight ratio of mixed fabric material in particulate form : aqueous feed comprising hydrochloric acid of between 1 : 2 and 1 : 50, preferably between 1 : 5 and 1 : 30.

5. Process according to any of the preceding claims, wherein the average residence time of the first continuous extraction device in step III. is the same or shorter than the average residence time in the CSTR, preferably at least 10% shorter.

6. Process according to any of the preceding claims, wherein the average residence time of the second continuous extraction device in step IV. has an average residence time which is the same or shorter than the average residence time of the first extraction device, preferably at least 10% shorter.

7. Process according to any of the preceding claims, wherein the temperature of the reaction in step II. of said mixture is between 70 and 110°C, preferably between 75 and 100°C.

8. Process according to any of the preceding claims, wherein in step I. the volume ratio organic extraction solvent : aqueous feed comprising hydrochloric acid is between 0.5 : 1 and 20 : 1, preferably between 1 : 1 and 10 : 1, and / or wherein in step III. the volume ratio organic extraction solvent : aqueous fraction comprising hydrochloric acid is between 0.5 : 1 and 20 : 1, preferably between 1 : 1 and 10 : 1.

9. Process according to any of the preceding claims, wherein the first continuous extraction device and / or second continuous extraction device is a column for reactive extraction.

10. Process according to any of the preceding claims, wherein the aqueous fraction comprising hydrochloric acid produced by the first continuous extraction device and / or produced by the second continuous extraction device is subjected to purification to yield purified aqueous hydrochloric acid.

11. Process according to any of the preceding claims, wherein the organic extraction solvent comprises a halogenated aromatic solvent, diisopropyl ether, ethyl acetate, pentane, hexane, heptane, octane, decane, dodecane, cyclohexane, benzene, toluene, xylene, chloroform, 1,2- dichloroethane, carbon tetrachloride, trichloromethane, and mixtures thereof.

12. Process according to claim 11, wherein the wherein the halogenated aromatic extraction solvent is selected from the group consisting of: mono-chlorobenzene, o-dichlorobenzene, m- dichlorobenzene, p-dichlorobenzene, 1,2,4-trichlorobenzene, mono-fluorobenzene, o- difluorobenzene, m-difluorobenzene, p-diflurorobenzene, 1,2,4-trifluorobenzene, 1,3- dichloro-2-fluorobenzene, fluorotoluene, chlorotoluene, and mixtures thereof.

13. Process according to any of the preceding claims, wherein the mixed fabric material in particulate form comprises cellulosic fibre material in an amount of 40 to 98% by weight, preferably 50 to 98% by weight.

14. Process according to any of the preceding claims, wherein the mixed fabric material comprises 2 - 40% by weight of one or more of man-made polyester fibre material, polyethylene fibre material, polypropylene fibre material, preferably 2 -30% by weight, and wherein the manmade polyester is preferably PET.

5. Process according to any of the preceding claims, wherein in step V. the 5- (chloromethyl)furfural present in the first and / or second organic extraction fraction obtained in step III. and / or step IV. is converted into 5-hydroxymethylfurfural, 5- methoxymethylfurfural, or 5-ethoxymethylfurfural, or mixtures thereof.

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