Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
  • C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
  • C07D307/34—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
  • C07D307/38—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with substituted hydrocarbon radicals attached to ring carbon atoms
  • C07D307/40—Radicals substituted by oxygen atoms
  • C07D307/46—Doubly bound oxygen atoms, or two oxygen atoms singly bound to the same carbon atom
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
  • C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
  • C07D307/34—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
  • C07D307/38—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with substituted hydrocarbon radicals attached to ring carbon atoms
  • C07D307/40—Radicals substituted by oxygen atoms
  • C07D307/46—Doubly bound oxygen atoms, or two oxygen atoms singly bound to the same carbon atom
  • C07D307/48—Furfural
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D11/00—Solvent extraction
  • B01D11/04—Solvent extraction of solutions which are liquid

Definitions

• Disclosed is a method for producing an aqueous solution of 5-hydroxymethylfurfural (5-HMF) of high purity.
• 5-HMF is a compound of interest derived from biomass that can be used in many fields, particularly in pharmacy, agrochemicals or specialty chemicals.
• the production of 5-HMF by dehydration of sugars has been known for many years and has been the subject of a large number of research works. There are many dehydration conditions, examples of which include the following methods:
• - 5-HMF can be obtained in an aqueous medium, generally in the presence of an acid catalyst.
• This acid catalyst makes it possible to dehydrate the C6 sugar (in particular fructose) into 5-HMF, but also catalyzes the rehydration of 5-HMF into formic acid and levulinic acid, which is highly detrimental to the yield.
• 5-HMF can also be obtained in a practical non-aqueous polar medium, with solvents such as methanol, ethanol or acetic acid, and in the presence of an acid catalyst. Under these conditions, 5-HMF is obtained as a mixture with an ether or ester derivative of 5-HMF depending on the reaction medium used. The formation of these secondary products is due to the reaction of 5-HMF with the reaction solvent in an acid medium.
• Application WO 2007/104514 describes the synthesis of 5-HMF by dehydration of sugar using methanol or ethanol as solvent in the presence of an acid catalyst. In this case, the presence of said catalyst also catalyzes the reaction of etherification of 5-HMF by alcohol to give a mixture of 5-HMF and its form of methyl or ethyl ether depending on the alcohol used as solvent.
• - 5-HMF can also be produced in an aprotic polar medium with or without an acid catalyst.
• DMSO dimethyl sulfoxide
• a known method for isolating 5-HMF from DMSO is liquid-liquid extraction, followed by crystallization of the extract, as described in patent FR 2669635.
• the applicant has already proposed an improvement to the method described in patent FR 2669635, which was the subject of patent FR 1758605.
• This improvement is based on the modification of the extraction step, in particular by adding a backwashing step to the water, and by recycling the water from backwash at the optional filtration step.
• This improvement makes it possible to increase the purity of 5-HMF without loss of yield of the product of interest, and to carry out the crystallization step of 5-HMF under more favorable conditions.
• the applicant has discovered a process making it possible to recover 5-HMF not in crystallized form but in aqueous solution, which opens up new possibilities for the valorization of 5-HMF in various applications, or for subsequent transformations which could not be performed neither in DMSO nor in the extraction solvent. Furthermore, the process according to the invention thus makes it possible to recover 5-HMF in aqueous solution, while limiting the costs of operability, water discharges and therefore the environmental impact of the process.
• An object of the present invention relates to a process for the production of an aqueous solution of 5-HMF of high purity.
• the invention relates more particularly to a method for producing an aqueous solution of 5-hydroxymethylfurfural (5-HMF), said method comprising the following steps:
• DMSO dimethoxysulfoxide
• the method for producing an aqueous solution of 5-HMF may optionally further comprise a step e) of concentrating the aqueous counter-extract from step d) by removal of an aqueous effluent, to produce a concentrated aqueous solution comprising 5-HMF.
• it also comprises a step f) for treating the water-DMSO mixtures produced within the process, to produce a treated aqueous effluent, which can be used in whole or in part in step c) for backwashing, and/ or in step d) of counter-extraction.
• the various ranges of parameters for a given stage such as the pressure ranges and the temperature ranges can be used alone or in combination.
• a preferred range of pressure values can be combined with a more preferred range of temperature values.
• charge 1 comprising 5-HMF and dimethoxysulphoxide (DMSO) introduced in stage a) according to the invention can be obtained during a stage of dehydration of sugars into 5-HMF, very advantageously located upstream of step a) according to the invention, by bringing a sugar feed comprising one or more sugars into contact with DMSO and an acid dehydration catalyst so as to produce an effluent containing at least 5-HMF and DMSO and advantageously corresponding to charge 1 of the process according to the invention introduced in stage a) of mixing.
• the method according to the invention can therefore optionally include a stage of dehydration of sugars into 5-HMF, located upstream of stage a).
• acid dehydration catalyst means any Bronsted acid catalyst chosen from organic or inorganic, homogeneous or heterogeneous Bronsted acids, capable of inducing the dehydration of sugars to 5-HMF.
• the acid dehydration catalyst is a Bronsted acid having a pKa in DMSO of between 0 and 5.0, preferably between 0.5 and 4.0 and more preferably between 1.0 and 3.0.
• Said pKa are as defined in the article by F. G. Bordwell et al. (J.Am. Chem. Soc., 1991, 113, 8398-8401).
• the acid dehydration catalyst is chosen from HF, HCl, HBr, HI, H 2 SO 3 , H 2 SO 4 , H 3 PO 2 , H 3 PO 4 , HNO 2 , HNO 3 , H2WO 4 , H 4 SiW 12 O 40 , H3PW 12 O 40 , (NH 4 ) 6 (W 12 O 40 ).xH 2 O, H 4 SiMo 12 O 40 , H 3 PMo 12 O 40 , (NH4) 6 Mo 7 O 24 .xH 2 O, H 2 MoO 4 , HReO 4 , H 2 CrO 4 , H 2 SnO 3 , H 4 SiO 4 , H 3 BO 3 , HCIO 4 , HBF 4 , HSbF5, HPF 6 , H 2 FO 3 P, CISO 3 acid _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
• the acid dehydration catalyst is chosen from HCl, H 2 SO 4 , H 3 PO 2 , H 3 PO 4 , HNO 3 , AICI 3 , acetic acid, trifluoroacetic acid, methanesulfinic acid, methanesulfonic acid, trifluoromethanesulfonic acid.
• sugar we mean a sugar containing 6 carbon atoms (hexoses), but this does not exclude the presence in the feed of sugars containing 5 carbon atoms (pentoses), in the form of oligosaccharides and monosaccharides.
• sugar is meant glucose or fructose, alone or in a mixture, sucrose, but also oligosaccharides such as cellobiose, maltose, cellulose or even inulin.
• the sugar filler used can be sugar in solid form, or else an aqueous sugar solution.
• sucrose is generally produced in the form of a solid
• glucose or fructose alone or in a mixture
• aqueous solution for example at 70% weight in sugar.
• the optional dehydration step is carried out at a temperature of between 50 and 150°C, preferably between 60 and 140°C, preferably between 70 and 130°C and more preferably between 80 and 120°C.
• the optional dehydration step is carried out at a pressure of between 1 and 0.001 MPa, preferably between 0.1 and 0.01 MPa.
• the reaction medium is above or below the bubble point of the mixture. Bubble point refers to the pressure and temperature conditions under which the first gas bubbles appear for a liquid.
• the reaction medium is above the bubble point of the mixture, the vapor phase can be withdrawn from the reactor, optionally rectified, and condensed to form the condensates which can be sent to an optional stage f) treatment of the water-DMSO mixtures .
• the acid dehydration catalyst is introduced in the dehydration stage in a molar ratio of the catalyst relative to the sugar charge, denoted Acid/Sugar, expressed in molar percentage (%mol), of between 0.01 and 10 %mol, preferably between 0.05 and 8%mol, preferably between 0.1 and 6%mol, preferably between 0.2 and 5%mol, preferably between 0.3 and 4%mol and so very preferably between 0.5 and 3% mol.
• %mol molar percentage
• the effluent obtained at the end of the optional dehydration step comprises 5-HMF and DMSO.
• the DMSO generally represents between 30 and 95% by weight of the effluent resulting from the dehydration step and treated in step a) of the process according to the invention, preferably between 40 and 90% by weight, preferably between 50 and 90% by weight, preferably between 55 and 85% by weight.
• 5-HMF represents more than 1% by weight of the effluent from the optional dehydration step and treated in step a) of the process according to the invention, preferably more than 10% by weight, preferably more than 15 wt% and preferably less than 50 wt%, preferably less than 40 wt%, preferably less than 30 wt%.
• said effluent from the optional dehydration step may contain water even before it is mixed in step a) with the intermediate aqueous counter-extract 9.
• Said water may be from the dehydration step, for example, water is formed during the dehydration reaction of sugar to 5-HMF (3 moles of water generated per mole of 5-HMF produced). This water may also have been introduced with the sugar, in the event that, for practical reasons, a sugar syrup, for example at around 70% by weight in water, is used.
• a water-DMSO mixture can be recovered in the vapor phase. Said water-DMSO mixture is advantageously sent to optional step f).
• the effluent from the optional dehydration step and introduced in step a) as feed 1 may contain water, in a proportion generally between 0.1 and 30% by weight, preferably between 0. 1 and 15% by weight, preferably between 0.1 and 10% by weight.
• the effluent from the optional dehydration step and introduced in step a) as feed 1 may also contain impurities, in particular humins.
• humins refers to all the undesirable polymeric compounds formed during the synthesis of 5-HMF.
• the homins represent, in particular, less than 30% by weight of the sugar feedstock converted, preferably less than 20% by weight.
• the optional dehydration step can be carried out according to different embodiments.
• the step can advantageously be implemented discontinuously or continuously.
• the addition of the sugar charge can be progressive (called fed-batch according to the English terminology) in the case of a discontinuous implementation or staged in different CSTR reactors (Continuously Stirred Tank Reactor in English terminology) in series in a setting. ongoing implementation. It is possible to operate in a closed reaction chamber or in a semi-open reactor.
• the method according to the invention comprises a step a) of bringing the filler 1, optionally resulting from the dehydration step, into contact with at least a fraction of an intermediate aqueous counter-extract 9 so as to obtain an aqueous mixture 3.
• the intermediate aqueous counter-extract 9 comes from step c) of the process according to the invention.
• the 5-HMF represents more than 1% by weight of the charge 1 introduced in step a) of the process according to the invention, preferably more than 10% by weight, preferably more than 15% by weight and preferably less 50% by weight, preferably less than 40% by weight, preferably less than 30% by weight.
• the DMSO represents between 30 and 95% by weight of the filler 1 introduced in step a), preferably between 40 and 90% by weight, preferably between 50 and 90% by weight, preferably between 55 and 85% weight.
• the filler 1 introduced in step a) may also contain water, in a proportion preferably between 0.1 and 30% by weight, preferably between 0.1 and 15% by weight and more preferably between 0.1 and 10% by weight.
• charge 1 may additionally contain humins.
• the humins represent, in particular, less than 30% by weight of the filler 1, preferably less than 20% by weight.
• the intermediate aqueous counter-extract 9 or the fraction of the intermediate aqueous counter-extract 9 advantageously comes from step c). It includes water, DMSO and possibly 5-HMF.
• the intermediate aqueous counter-extract 9 contains more than 60% by weight of water, preferably more than 70% by weight of water and preferably more than 80% by weight of water.
• the aqueous mixture 3 obtained in step a) contains between 10% and 90% by weight of water, preferably between 20 and 80% by weight of water, preferably between 40 and 75% by weight of water.
• step a) is carried out at a temperature of 0 to 60°C, preferably of 10 to 30°C and generally at ambient temperature, that is to say between 18 and 25°C.
• Step a) can optionally be additionally supplied with an aqueous stream, for example with a fraction of the aqueous solvent used in step c) for backwashing.
• step a By increasing the water content during step a), for example by introducing at least a fraction of the intermediate aqueous counter-extract 9, part of the humins possibly present in the load 1 can precipitate.
• the mixture resulting from the contact of said charge 1 with at least a fraction of the intermediate aqueous counter-extract 9 can therefore advantageously be subjected to a liquid-solid separation step, so as to obtain a liquid separated from solid particles in suspension and a residue solid comprising humins and which is preferably removed from the process.
• a liquid-solid separation step thus makes it possible to eliminate the "humins" which have precipitated.
• At least part of the liquid obtained is then advantageously sent to step b) of liquid-liquid extraction, said part (or all) of the liquid advantageously sent to step b) corresponding to the aqueous mixture 3.
• This optional step liquid-solid separation is preferably carried out at a temperature between 0 and 60°C, preferably between 10 and 30°C, preferably between 15 and 25°C and generally at room temperature (i.e. between 18 and 25°C).
• the optional liquid-solid separation step can be carried out by any method known to those skilled in the art, such as for example with a filter press, a belt filter, a clarifier, a decanter, a centrifuge, for example a centrifuge to plate.
• the liquid-solid separation step is filtration, preferably carried out by a filter press.
• the method according to the invention comprises a step b) of liquid-liquid extraction of the mixture 3 obtained at the end of step a) in the presence of a stream 4 of extraction solvent, so as to produce a raffinate aqueous 5 and an intermediate organic extract 6.
• the liquid-liquid extraction carried out in step b) advantageously corresponds to washing the aqueous mixture with an organic extraction solvent.
• the liquid-liquid extraction carried out in step b) is a countercurrent extraction of the aqueous mixture 3 obtained in step a) by a flow of extraction solvent.
• the extraction can be carried out, for example, in a battery of mixer-settlers, in a column filled with bulk or structured packing, in a pulsed column, or even in a stirred column.
• Step b) of extraction is advantageously carried out at a temperature between 0 and 60°C, preferably between 5 and 50°C, preferably between 10 and 40°C, preferably between 15 and 30°C and generally at room temperature (i.e. between 18 and 25°C).
• the proportion (weight/weight) of the flow of extraction solvent relative to the aqueous mixture 3 is preferably from 0.2 to 5, preferably between 1 and 3, preferably between 1.5 and 2.5.
• the extraction solvent is chosen from solvents which are immiscible with water, so as to form two liquid phases in particular in step c) of backwashing and in step d) of back-extraction. This property is highly dependent on the relative proportion of feed, counter-extraction water and extraction solvent flow rates used in the process.
• the extraction solvent is preferably chosen from the family of chlorinated organic solvents, ethers, esters, ketones and aromatic compounds.
• the extraction solvent is a chlorinated solvent having between 1 and 10 carbon atoms, noted below as C1 -C10, an ether having between 2 and 10 carbon atoms (C2-C10), an ester having between 4 and 10 carbon atoms (C4-C10), a ketone having between 3 and 10 carbon atoms (C3-C10), an aldehyde between 1 and 10 carbon atoms (C1-C10), an aromatic compound C4-C10.
• the extraction solvent is chosen from dichloromethane, diethyl ether, diisopropyl ether, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, thiophene, anisole and toluene.
• the extraction solvent is methyl isobutyl ketone.
• the streams of organic solvent produced in the subsequent stages can be advantageously recycled to stage b) of extraction.
• These organic solvent streams may contain impurities produced within the process.
• the organic solvent can be periodically distilled to avoid the accumulation of said impurities.
• the extraction solvent stream comprises, preferably consists of, a stream resulting from one of the steps of the process according to the invention.
• the extraction solvent stream comprises, preferably consists of, at least a fraction, preferably all, of an organic effluent, advantageously resulting from stage d) of counter-extraction and recycled to stage b) of extraction, the fraction or all of the organic effluent advantageously resulting from stage d) of counter-extraction possibly being able to be mixed with fresh extraction solvent, that is to say external to the process, to constitute the stream of extraction solvent introduced in step b).
• Extraction step b) thus makes it possible to obtain, on the one hand, an aqueous stream depleted in 5-HMF, called aqueous raffinate 5, which contains a large part of the DMSO initially contained in a charge, and on the other hand an organic stream enriched in 5-HMF, called intermediate organic extract 6, which contains a large part of the 5-HMF, initially contained in the charge 1, and the extraction solvent.
• This intermediate organic extract 6 may also contain DMSO.
• said extract contains 5-HMF and DMSO in a weight ratio, 5-HMF/DMSO, of between 50/50 and 95/05, preferably between 55/45 and 90/10, preferably between 60/ 40 and 85/15 and preferably between 65/35 and 80/20.
• the intermediate organic extract 6 is sent to stage c) of backwashing.
• the process according to the invention comprises a step c) of backwashing, advantageously of the intermediate organic extract 6, with an aqueous solvent 7 so as to produce an intermediate aqueous counter-extract 9 and an organic raffinate 8 comprising 5- HMF and an organic solvent.
• the organic solvent is in particular composed at least in part of extraction solvent and may optionally comprise DMSO, preferably in small quantities.
• the intermediate aqueous counter-extract 9 is sent in part or in whole to step a).
• the introduction of an aqueous solvent in step c) is carried out in such a way as to implement backwashing, according to the general knowledge of those skilled in the art.
• the introduction of the aqueous solvent is carried out in such a way that the quantity of aqueous solvent is as low as possible so as to reduce costs, but sufficient to guarantee a content by weight of DMSO in the organic raffinate 8 which is low and preferably lower or equal to 20.0% by weight relative to the weight of the 5-HMF, preferably less than or equal to 15.0% by weight relative to the weight of the 5-HMF, preferably between 0.01 and 15.0% by weight per relative to the weight of the 5-HMF, and preferably between 0.01 and 10.0% by weight relative to the weight of the 5-HMF.
• the aqueous backwashing solvent introduced in step c) comprises more than 95% by weight of water, preferably more than 98% by weight of water (100% being the maximum).
• the aqueous solvent may optionally include DMSO.
• the effectiveness of the backwash is higher the lower the amount of DMSO present in the aqueous backwash solvent.
• the aqueous solvent may comprise DMSO, preferably less than 1.0% by weight of DMSO, preferably less than 0.1% by weight of DMSO.
• the aqueous backwashing solvent comes from an optional stage f) of treatment of water-DMSO mixtures produced within the process and/or from an optional stage e) of concentration.
• the aqueous raffinate 5 composed of water and DMSO produced in step b) is advantageously treated in step f) optional which includes in particular a distillation.
• the water-rich distillate 7 obtained at the end of this optional step f) is advantageously used as aqueous solvent for backwashing in step c), said water-rich distillate also possibly containing a residual quantity of DMSO, preferably less than 1% by weight and preferably less than 0.1% by weight of DMSO.
• the residual quantity of DMSO is all the lower as the distillation of optional step f) is carried out efficiently, in particular with a number of distillation stages greater than 10 and with suitable reboiling and reflux ratios .
• Step c) of backwashing is advantageously a liquid-liquid extraction of the intermediate organic extract 6 obtained in step b) against the current of the aqueous solvent 7 introduced.
• This technique is well known to those skilled in the art.
• the extraction can be carried out, for example, in a battery of mixer-settlers, in a column filled with bulk or structured packing, in a pulsed column, or even in a stirred column.
• Step c) is generally carried out at a temperature between 0 and 60°C, preferably between 5 and 50°C, preferably between 10 and 40°C, preferably between 15 and 30°C and generally at room temperature (i.e. between 18 and 25°C).
• the mass ratio (weight/weight) of aqueous solvent relative to the intermediate organic extract 6 is preferably from 0.04 to 5, preferably between 0.07 and 3, preferably between 0.1 and 1.
• Step c) makes it possible to obtain an aqueous stream enriched in DMSO, called intermediate aqueous counter-extract 9, preferably containing at least 60% by weight of water, preferably at least 80% by weight of water, and an organic raffinate 8 advantageously depleted in DMSO.
• Said intermediate aqueous counter-extract 9 is advantageously sent, in part or preferably in whole, to stage a) of mixing.
• the organic raffinate 8 obtained has a content by weight of DMSO preferably less than or equal to 20.0% by weight relative to the weight of 5-HMF, preferably less than or equal to 15.0% by weight relative to the weight of 5-HMF preferably less than or equal to 5.0% by weight relative to the weight of 5-HMF, preferably less than or equal to 4.0% by weight relative to the weight of 5-HMF, preferably less than or equal to 3.0% weight relative to the weight of 5-HMF.
• the organic raffinate 8 produced in step c) is sent to step d) for counter-extraction.
• the method according to the invention comprises a step d) of counter-extraction of the organic raffinate 8 by an aqueous flow 10, so as to produce an aqueous counter-extract 11 comprising the 5-HMF and an organic effluent comprising the extraction solvent .
• the aqueous counter-extract 1 1 comprises 5-HMF preferably at a content greater than or equal to 40% by weight, preferably greater than or equal to 50% by weight, relative to all the organic compounds, that is to say ie compared to the whole 5-HMF, DMSO and extraction solvent.
• the process according to the invention makes it possible to obtain an aqueous counter-extract of 5-HMF of very high purity, containing a very small quantity of humins, in particular in the trace state (i.e. that is to say not quantifiable, even not detected by HPLC liquid chromatography), even devoid of humins.
• the introduction of the aqueous stream 10 in step d) is carried out in such a way as to implement the counter-extraction according to the general knowledge of those skilled in the art.
• the quantity of the aqueous stream 10 introduced is adjusted so as to be as low as possible in order to reduce costs, but sufficient to guarantee effective counter-extraction of the 5-HMF.
• at least 90% by weight, preferably at least 95% by weight, very preferably at least 98% by weight, of the 5-HMF contained in the organic raffinate 8 which feeds step d) are counter-extracted and thus advantageously found in the aqueous counter-extract 11.
• the counter-extraction carried out in step d) is a counter-current extraction of the organic raffinate 8 obtained at the end of step c) by an aqueous flow 10.
• This technique is well known to the man of the trade.
• the extraction can be carried out, for example, in a battery of mixer-settlers, in a column filled with bulk or structured packing, in a pulsed column, or even in a stirred column.
• Step d) of back-extraction is preferably carried out at a temperature between 0 and 60°C, preferably between 5 and 50°C, preferably between 10 and 40°C, preferably between 15 and 30°C , and in particular at ambient temperature (that is to say between 18 and 25° C.).
• the proportion (weight/weight) of the aqueous stream 10 relative to the organic raffinate 8 is preferably from 0.5 to 5, preferably between 1.0 and 3.0, preferably between 1.5 and 2.5.
• the amount of water from the aqueous stream added in step d) of back-extraction is greater than the amount of water from the aqueous solvent added in step c) of back-washing.
• the aqueous stream 10 introduced in step d) of back-extraction comprises at least 95% by weight of water, preferably at least 98% by weight of water (100% being the maximum).
• the aqueous stream may optionally include DMSO.
• the aqueous stream comprises less than 1.0% by weight of DMSO, preferably less than 0.1% by weight of DMSO.
• the aqueous counter-extraction solvent is derived, at least in part, from an optional step f) of treatment of water-DMSO mixtures produced within the process and/or from an optional step e) of concentration.
• the aqueous raffinate 5 composed of water and DMSO, produced in stage b), is treated, advantageously in an optional stage f) which comprises in particular distillation, and the water-rich distillate obtained in resulting from this optional step f) is advantageously used, at least in part, as an aqueous counter-extraction stream in step d), the water-rich distillate obtained at the end of this optional step f) can also contain a residual quantity of DMSO, preferably less than 1% by weight and more preferably less than 0.1% by weight of DMSO.
• an aqueous solution comprising 5-HMF, corresponding to the aqueous counter-extract 11, and an organic effluent comprising the extraction solvent.
• the process according to the invention thus makes it possible to obtain an aqueous solution of 5-HMF of high purity, that is to say comprising a very small quantity of humins, in the form of traces, or even free of humins.
• the aqueous counter-extract 11 produced in step d) can advantageously be sent, in whole or in part, to an optional concentration step e).
• the organic effluent can be recycled, in whole or in part, to step b) of extraction to compose at least a fraction of stream 4 of extraction solvent.
• the aqueous counter-extract 11 can be concentrated into a concentrated aqueous solution 12 of 5-HMF by eliminating an aqueous effluent 13.
• the concentration of the aqueous solution is carried out by any method known to those skilled in the art, such as for example by evaporation or distillation or even reverse osmosis. .
• the concentrated aqueous solution 12 of 5-HMF obtained at the end of optional step e) comprises 5-HMF, at a content greater than or equal to 30% by weight, preferably greater than or equal to 40% by weight, preferably greater than or equal to 50% by weight, and water.
• the aqueous solution 12 of 5-HMF obtained at the end of optional step e) comprises at most 90% by weight of 5-HMF, preferably at most 85% by weight of 5-HMF and preferably at most 80% by weight of 5-HMF, the balance at 100% being very advantageously essentially water.
• the aqueous solution 12 of 5-HMF obtained at the end of optional step e) therefore very preferably comprises at least 10% by weight of water, preferably at least 15% by weight of water, preferably at least least 20% by weight of water, and very preferably up to 70% by weight of water, in particular up to 50% by weight of water, in particular up to 30% by weight of water.
• the DMSO content of concentrated aqueous solution 12 is very low, preferably less than 0.1% by weight, preferably less than 500 ppm by weight and preferably less than 100 ppm by weight relative to the weight of 5-HMF.
• the aqueous effluent 13 obtained at the end of the optional concentration step e) is composed essentially of water, preferably more than 95% by weight of water, preferably more than 98% by weight of water (100% being the maximum).
• the aqueous effluent 13 can advantageously be recycled to stages c) backwashing and/or d) back-extraction.
• the method according to the invention may comprise an optional step f) of treatment of water-DMSO mixtures generated by the steps of the method according to the invention, to produce a treated aqueous effluent (also called distillate), which can be used in whole or part in step c) of back-washing and/or in step d) of back-extraction.
• This step can also produce a DMSO-rich stream and an impurity stream.
• the residual quantity of DMSO in the treated aqueous effluent produced at the end of optional step f) is all the lower as the distillation is carried out efficiently according to the knowledge of those skilled in the art.
• the water-DMSO mixtures generated by the process designate in particular the aqueous raffinate 5 produced in stage b) and possibly the water-DMSO mixture resulting from the optional stage of dehydration of the sugars into 5-HMF when the process incorporates such a stage.
• the water-DMSO mixtures generated by the process designate in particular the aqueous raffinate 5 produced in stage b), and possibly the water-DMSO mixture resulting from the optional stage of dehydration of the sugars into 5-HMF when the process incorporates a such step.
• the optional step f) for treating water-DMSO mixtures preferably implements a section for evaporating a water-DMSO mixture, to remove any impurities, in particular heavy impurities such as humins, followed by a distillation section.
• the evaporation section is operated at a temperature preferably between 80 and 120° C., preferably between 100 and 110° C., and preferably at a pressure between 0.002 and 0.020 MPa, preferably between 0.005 and 0.01 OMPa.
• the evaporation section is implemented by a scraped film type evaporator (Thin film Evaporator TFE).
• the distillation section for its part, advantageously implements a distillation column or several separate pieces of equipment.
• the distillation section of optional step f) is advantageously implemented in a distillation column, at a temperature at the top of the column preferably between 25 and 60° C., preferably between 45 and 55° C., for example about 50° C., preferably at a temperature at the bottom of column between 80 and 120° C., preferably between 105 and 115° C., for example approximately 110° C., preferably at a pressure between 0.001 and 0.05 MPa, preferably between 0.005 and 0.02 MPa and preferably between 0.008 and 0.012 MPa, and preferably with a reflux ratio of between 0.01 and 0.50, preferably between 0.05 and 0.10.
• the aqueous raffinate 5 produced in step b) and comprising water and DMSO and optionally the water-DMSO mixture recovered in the optional dehydration step are evaporated then the gaseous phase is recovered and distilled, preferably under vacuum, so as to produce a DMSO-rich residue on the one hand and a water-rich distillate (corresponding to the treated aqueous effluent) on the other hand. Rich here means more than 95% by weight, preferably more than 98% by weight. Part or all of the water-rich distillate, or treated aqueous effluent, can advantageously be recycled to step c) as aqueous solvent to carry out the backwashing step and/or to step d) of counter-extraction as an aqueous stream.
• the water-rich distillate can also be, in whole or in part, recycled as water introduced in step a).
• the DMSO-rich residue can advantageously be introduced at the optional dehydration stage, directly or after distillation, allowing the heavy products which could accumulate to be evacuated.
• FIG. 1 illustrates an embodiment of the method according to the invention.
• the charge 1) containing 5-HMF, DMSO and humins is sent to step a) of mixing and is brought into contact with the intermediate aqueous counter-extract 9 from step c) then the humins 2 which precipitated are removed from the mixture by liquid-solid filtration.
• the aqueous mixture 3 obtained at the end of step a) is sent to step b) for extraction and placed in the presence of an extraction solvent 4 recycled from step d), in order to extract the 5-HMF of the aqueous mixture with the extraction solvent and to obtain an aqueous raffinate 5 and an intermediate organic extract 6.
• the intermediate organic extract 6 is placed in the presence of an aqueous solvent 7 in step c) backwash.
• the organic raffinate 8 obtained is sent to stage d) of counter-extraction and placed in the presence of an aqueous stream 10 in order to extract the 5-HMF in water and form an aqueous stream 11 .
• the aqueous stream 11 is then advantageously concentrated in step e) to obtain an aqueous solution 12 of 5-HMF and an aqueous effluent 13.
• Example 1 process according to the invention
• Example 1 presents the method and the results obtained by an example of the method according to the embodiment of the invention of Figure 1.
• An acid catalyst methanesulfonic acid
• DMSO molar ratio with the sugar charge (catalyst/sugar charge) is 1% mol, and they are brought to a temperature of 120°C.
• the fructose is introduced in the form of an aqueous solution, at 70% sugar weight (syrup), in a DMSO/fructose mass ratio of 2.3.
• the pressure is maintained at 0.035 MPa. Under these pressure and temperature conditions, the reaction medium is above the bubble point of the mixture, so the vapor phase can be withdrawn from the reactor, and condensed to form the condensates.
• the sugar dehydration step is implemented discontinuously with a gradual addition of charge for 2 hours.
• the reaction medium is maintained at the temperature and pressure indicated above for an additional 2 h after the end of the addition.
• the effluent from the dehydration step contains 74% by weight of DMSO, 21% by weight of 5-HMF, 3% by weight of water, i.e. a molar yield of 5-HMF relative to the fructose involved of 81%.
• Polymeric compounds (called humins) soluble in the reaction medium were formed up to 5% by weight.
• a water-DMSO mixture is recovered in the vapor phase. Said water-DMSO mixture has a composition of 32% by weight of DMSO and 68% of water. This water-DMSO mixture is vacuum distilled to produce water containing only traces of DMSO.
• the liquid effluent from the dehydration stage corresponding to charge 1 is engaged in a stage a) of bringing into contact with water, at ambient temperature, so as to obtain a mixture which contains a mass ratio DMSO/ water equal to 1.
• the mixture from step a) is subjected to a liquid-solid separation step, on a Büchner filter equipped with a polypropylene mesh filter with a pore size of 10 ⁇ m.
• This liquid-solid separation step is carried out at ambient temperature.
• 7.5 g of a “humin” solid residue/kg of filtered mixture are recovered, as well as a homogeneous liquid phase corresponding to the aqueous mixture 3.
• the aqueous mixture 3 is composed of 43% by weight of DMSO, 12% by weight of 5-HMF, 43% by weight of water and includes impurities (approximately 2% by weight of humins).
• the aqueous mixture 3 resulting from stage a) is subjected to a stage b) of countercurrent liquid-liquid extraction in a stirred column (ECR or Kühni type) made of glass comprising 8 sections 225 mm high and internal diameter of 32 mm, as well as a lower decanter and an upper decanter.
• the useful height is approximately 1.8 m and the total height of the column is 2.60 m.
• the total volume is about 3 liters.
• the organic extraction solvent is methyl isobutyl ketone (or MIBK for methyl isobutyl ketone in Anglo-Saxon terms).
• the aqueous mixture 3 is introduced into the upper part of the device and dispersed in the ascending organic phase.
• the column inlet flow rates are set at 2.2 kg/h for the DMSO-water phase and at 4.1 kg/h for the organic solvent.
• the proportion (weight/weight) of MIBK solvent is 1.9 relative to the aqueous mixture 3 from step b).
• the temperature is 20° C. and the stirring speed 300 rpm.
• the extraction yield is 97% for 5-HMF and 13% for DMSO.
• the intermediate organic extract 6 from stage b) of liquid-liquid extraction is subjected to a stage c) of backwashing in the same type of extraction device (stirred column ECR or Bruhni type). Said organic extract is dispersed in the descending phase of pure water, at 21.5°C.
• the column inlet flow rates are set at 5 kg/h for the organic extract and at 1.5 kg/h for the aqueous phase.
• the proportion (weight/weight) of water introduced as aqueous backwash solvent relative to the intermediate organic extract is 0.3.
• the organic raffinate 8 from stage c) backwashing is subjected to stage d) liquid-liquid back-extraction in the same type of extraction device (stirred column ECR or Bruhni type).
• Said organic raffinate 8 is dispersed in the descending phase of pure water, at 21.5°C and 300 rpm.
• the column inlet flow rates are set at 2.2 kg/h for the organic raffinate and at 4.4 kg/h for the aqueous phase.
• the proportion (weight/weight) of water introduced in step d) relative to the organic raffinate 8 is 2.
• step d) of counter-extraction are recovered: an organic raffinate depleted in 5-HMF containing 0% by weight of DMSO, 0.15% by weight of 5-HMF and 96% by weight of MIBK, and an aqueous solution 11 enriched with 5-HMF containing 0.045% by weight of DMSO, 2.0% by weight of 5-HMF, 1.6% by weight of MIBK and approximately 96.4% by weight of water.
• the extraction yield is 97% for 5-HMF.
• the aqueous solution 11 does not comprise humins or only in the form of traces (not detected by liquid phase chromatography or HPLC).
• the aqueous solution 11 is then concentrated by distillation to obtain a concentrated aqueous solution 12 comprising 78% by weight of 5-HMF and an aqueous effluent 13.

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• 2021
  • 2021-12-23 FR FR2114337A patent/FR3131310B1/fr active Active
• 2022
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