Process for converting cellulose and / or starch or source thereof to 5- (chloromethyl)furfural

Abstract

A process for converting a composition comprising cellulose and / or starch into 5-(chloromethyl)furfural (CMF) with aqueous hydrochloric acid and multiple extractions using an organic extraction solvent. The process can be carried out batch-wise and in continuous fashion.

Description

[0001] PROCESS FOR CONVERTING CELLULOSE AND / OR STARCH OR SOURCE THEREOF TO 5- (CHLOROMETHYL)FURFURAL

[0002] Introduction

[0003] The present invention relates to a process for converting a source containing cellulose and / or starch into 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.

[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. H.H. Szmant et al (J. Chem. Tech. Biotechnol., 1981, 31, 205-212) disclose that fructose and high fructose corn syrup could be converted to CMF with 39% HCI in a yield of 90-95%. For glucose the yields were lower (30-45%), and for corn starch even less (14-20%). Fructose and high fructose corn syrup are sources having in common that these are carbohydrates which are also be used for high-value applications in the food industry and / or are relatively expensive. For glucose and corn starch the yields were too low to be commercially attractive.

[0007] M. Mascal et al (Angew. Chem. Int. Ed. 2008. 47, 1-4) disclose that microcrystalline cellulose can be converted into CMF 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] Additionally, the above references disclose methods which are suitable for performing research, but are not attractive for a commercial process of making CMF. Hence, there is a desire for a process to produce 5-(chloromethyl)furfural (CMF) or solution containing CMF in good yield which does not have the disadvantages that the prior art processes discussed above have and which process can preferably be carried out in a continuous way.

[0009] Summary of the invention

[0010] 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 a composition comprising cellulose and / or starch, said process comprising the steps of: a. mixing said composition comprising cellulose and / or starch with: an aqueous composition comprising hydrochloric acid at a concentration HCI of 18 - 42%, a first portion of organic extraction solvent, b. reacting said mixture at a temperature of between 60 and 120°C for a period of 10 minutes to 3 hours, c. separating an organic fraction comprising organic extraction solvent and 5-(chloromethyl)furfural from the remainder which comprises an aqueous fraction comprising hydrochloric acid, and cellulose and / or starch, d. adding and mixing a further portion of the organic extraction solvent to the aqueous fraction obtained in step c., and reacting the mixture at a temperature which is between 5 and 25°C higher than the temperature at which step b. is conducted, for a period of between 10 minutes to 2 hours, e. separating the organic liquid fraction comprising organic extraction solvent and 5- (chloromethyl)furfural from the remainder, 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.

[0011] The above is the first embodiment of the invention.

[0012] The invention further relates to process that may be practiced in a continuous way, for achieving the above objective, at least in part. Hence, the present invention further relates to a process for preparing 5- (chloromethyl)furfural from a composition comprising cellulose and / or starch, said process comprising the steps of:

[0013] I. providing to a CSTR (continuously stirred tank reactor): a feed composition comprising cellulose and / or starch, an aqueous feed comprising hydrochloric acid at a concentration HCI of 18 - 42%, 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, and cellulose and / or starch and / or carbohydrate oligomers, said continuous extraction device operating at a temperature of between 60 and 120°C 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, and which second continuous extraction device has an average residence time,

[0016] 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.

[0017] This is a second embodiment of the present invention.

[0018] Detailed description of the invention

[0019] It is known that cellulose and / or starch 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 and starch) 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.

[0020] 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 / starch. This is especially relevant for cellulose, but also applies to starch. 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.

[0021] The present invention (in both embodiments) yield 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 HMF or AMF (e.g. MMF, EMF).

[0022] 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.

[0023] 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.

[0024] During extraction step c. and d. (first embodiment) and III. and IV. (second embodiment) separation is achieved, but also reaction (production of CMF). Hence, in the present invention according to the first embodiment above it is preferred that the mixture in step d. is reacted for a duration which is less than the duration of the reaction in c., which in turn is reacted for a duration which is less than the duration of the reaction under b. Preferably said duration under d. is at least 10% less than the duration of the reaction under b., more preferably at least 20% less, even more preferably at least 30% less.

[0025] As to the second embodiment, 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.

[0026] 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 first embodiment according to the present invention it is preferred that the aqueous composition comprising hydrochloric acid in a. has a concentration HCI of at 19-40 wt%, preferably 30-39 wt%, more preferably 35-39 wt%. Likewise, in the second embodiment of 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 (both for first and second embodiment) in certain environments, 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 (both first and second embodiment) that the hydrochloric acid has a concentration found at the azeotrope of hydrochloric acid and water.

[0027] As to the amount of aqueous hydrochloric acid to be used in the first embodiment of the present invention, it is preferred that the cellulose and / or starch in a. are mixed with the aqueous hydrochloric acid in a weight ratio of cellulose and / or starch : aqueous HCI composition of between 1 : 2 and 1 : 50, preferably between 1 : 5 and 1 : 30. Similarly, it is preferred for the second embodiment of the present invention that the cellulose and / or starch in I. are mixed with the aqueous feed comprising hydrochloric acid in a weight ratio of cellulose and / or starch : aqueous feed comprising hydrochloric acid of between 1 : 2 and 1 : 50, preferably between 1 : 5 and 1 : 30.

[0028] In the presently claimed process described as the first embodiment above, the reaction of the aqueous hydrochloric acid on the cellulose and / or starch 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 b. of said mixture is between 70 and 110°C, preferably between 75 and 100°C. Likewise, for the second embodiment of the present invention 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. The CMF that is formed by the action of hydrochloric acid on the cellulose and / or starch 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, both for first and second embodiment, 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.

[0029] 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, both in the first embodiment and the second embodiment, 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 preferred.

[0030] In the first embodiment according to the present invention, it is preferred that in step a. and / or d. the volume ratio organic extraction solvent : aqueous composition (or aqueous fraction, for step d.) is between 0.5 : 1 and 20 : 1, preferably between 1 : 1 and 10 : 1. Likewise, for the second embodiment 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.

[0031] The second embodiment of the present invention is a way to carry out the first embodiment of the present invention in a continuous way.

[0032] 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 for the second embodiment that the first continuous extraction device and / or second continuous extraction device is a column for carrying out reactive extraction.

[0033] 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 second embodiment of 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.

[0034] Unlike one of the prior art processes, the now claimed process allows cellulose, also the recalcitrant parts thereof, to be hydrolysed with hydrochloric acid and converted to CMF, without the need to add lithium chloride or ensure lithium chloride is present. Hence, in the present invention, it is preferred that to the reaction mixture under a. in the first embodiment according to the invention no lithium chloride is added.

[0035] 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 by stage c. and / or e. (first embodiment) or stage V (second embodiment) 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 CM F conversions, a catalyst can be added to accelerate the CMF conversion reaction.

[0036] Alternatively, the 5-(chloromethyl)furfural (CMF) obtained in solution in stage c. (first embodiment) or stage d. (second embodiment) 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.

[0037] EXAMPLES

[0038] Example 1

[0039] For example 1, 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 1 below.

[0040] In table 1:

[0041] "comp." means comparative experiment, i.e. not according to the invention

[0042] "inv." means experiment according to the present invention

[0043] 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.

[0044] Some experiments were carried out twice with the same time / temperature combinations, as duplicate.

[0045] Procedure for all experiments:

[0046] 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.

[0047] Aqueous phase: ImL HCI 37%wt + 30 mg of starting material (cellulose)

[0048] Organic phase : 3mL fluorobenzene, 99%, Acros Organics Procedure experiments 14-02, 25-03, 25-04, 25-06, 25-07:

[0049] 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).

[0050] Procedure all other experiments:

[0051] 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.

[0052] For all experiments:

[0053] 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.

[0054] Sample preparation: ImL organic fraction + O.lmL Internal Standard (Dioxane in Toluene) Analysis: Performed by GC

[0055] Table 1: Cellulose as starting material

[0056]

[0057] Example 2 This was conducted in the same way as example 1, except that starch (conventional potato starch as available in Dutch supermarkets under consumer brand Honig) was used instead of cellulose. Conditions and results are in table 2.

[0058] The procedure for experiment 19-01 was the same as for experiments 14-02, 25-03, 25-04, 25-06, 25-07. The procedure for experiment 32-05 was the same as for e.g. experiment 32-02.

[0059] Table 2: potato starch as starting material

Claims

CLAIMS1. Process for preparing 5-(chloromethyl)furfural from a composition comprising cellulose and / or starch, said process comprising the steps of: a. mixing said composition comprising cellulose and / or starch with: an aqueous composition comprising hydrochloric acid at a concentration HCI of 18 - 42% a first portion of organic extraction solvent, b. reacting said mixture at a temperature of between 60 and 120°C for a period of 10 minutes to 3 hours, c. separating an organic fraction comprising organic extraction solvent and 5- (chloromethyl)furfural from the remainder which comprises an aqueous fraction comprising hydrochloric acid, and cellulose and / or starch, d. adding and mixing a further portion of the organic extraction solvent to the aqueous fraction obtained in step c., and reacting the mixture at a temperature which is between 5 and 25°C higher than the temperature at which step b. is conducted, for a period of between 10 minutes to 2 hours, e. separating the organic liquid fraction comprising organic extraction solvent and 5- (chloromethyl)furfural from the remainder, 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 composition comprising hydrochloric acid in a. 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 cellulose and / or starch in a. are mixed with the aqueous hydrochloric acid in a weight ratio of cellulose and / or starch : aqueous HCI composition of between 1 : 2 and 1 : 50, preferably between 1 : 5 and 1 : 30.

4. Process according to any of the preceding claims, wherein the mixture in step d. is reacted for a duration which is less than the duration of the reaction under b.

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

6. Process according to any of the preceding claims, wherein to the reaction mixture under a. and / or no lithium chloride is added.

7. Process for preparing 5-(chloromethyl)furfural from a composition comprising cellulose and / or starch, said process comprising the steps of:I. providing to a CSTR: a feed composition comprising cellulose and / or starch, an aqueous feed comprising hydrochloric acid at a concentration HCI of 18 - 42%, 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, and cellulose and / or starch and / or carbohydrate oligomers, said continuous extraction device operating at a temperature of between 60 and 120°C 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, 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.

8. Process according to claim 7, 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%.

9. Process according to claim 7 or 8, wherein cellulose and / or starch in I. are mixed with the aqueous feed comprising hydrochloric acid in a weight ratio of cellulose and / or starch : aqueous feed comprising hydrochloric acid of between 1 : 2 and 1 : 50, preferably between 1 : 5 and 1 : 30.

10. Process according to any of claims 7 to 9, 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 sum of the average residence time in the CSTR plus the average residence time of the first extraction device, more preferably at least 10% shorter.

11. Process according to any of claims 7 to 10, wherein the temperature of the reaction in step II. of said mixture is between 70 and 110°C, preferably between 75 and 100°C.

12. Process according to any of claims 7 to 11, 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.

13. Process according to any of claims 7 to 12, wherein the first continuous extraction device and / or second continuous extraction device is a column for reactive extraction.

14. 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.

15. Process according to claim 15, 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.

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