Method for producing acrolein

Abstract

The present invention relates to a method for producing acrolein from an aqueous solution of reuterin derived from fermentation, the method involving the separation of suspended solids followed by transformation of the reuterin into acrolein without addition of homogeneous acid, in a heterogeneous catalytic reactor. The acrolein produced within the context of the present invention can be used in various downstream applications, in particular as a raw material for the production of acrylic acid and its derivatives, methionine and its derivatives, or glutaraldehyde and its derivatives. The acrolein produced according to the invention may have a high biobased carbon content as defined by standards ASTM D6866 or EN 16640 when biobased raw materials are used to obtain the aqueous solution of reuterin from fermentation.

Description

[0001] DESCRIPTION

[0002] TITLE: PROCESS FOR THE MANUFACTURE OF ACROLIN

[0003] Domain

[0004] The present invention relates to a process for the production of acrolein from an aqueous solution of reuterin derived from fermentation, said process involving a transformation of the aqueous solution of reuterin into acrolein without the addition of homogeneous acid in a heterogeneous catalytic reactor after separation of suspended matter. The acrolein produced within the scope of the present invention can be used in various downstream applications, in particular as a raw material for the production of acrylic acid and its derivatives, methionine and its derivatives or glutaraldehyde and its derivatives. The acrolein produced within the scope of the invention can have a high content of bio-based carbon within the meaning of ASTM D6866 or EN 16640 standards when bio-based raw materials are used to obtain the aqueous solution of reuterin derived from fermentation.

[0005] Prior art and

[0006] Acrolein is the simplest of the unsaturated aldehydes. It is also known as 2-propenal, acrylaldehyde, or acrylic aldehyde. Due to its structure, acrolein has a high reactive power due to the presence of two reactive functions that can react individually or together. Therefore, acrolein has many applications, particularly as a synthesis intermediate. In particular, it is a key intermediate for the synthesis of methionine, which has established itself as an animal feed supplement as a substitute for fish meal. Acrolein is a synthesis intermediate in the industrial production of acrylic acid by gas-phase oxidation of propylene.Acrolein also leads, by reaction with methyl vinyl ether and then hydrolysis, to glutaraldehyde which has numerous uses in leather tanning, as a biocide in oil drilling, during the treatment of cutting oils, or as a chemical disinfectant and sterilizer for hospital equipment. Acrolein is most often used as an intermediate in the synthesis of derivatives which are synthesized on the producer's site due to the toxicity of the product which leads manufacturers to avoid the storage and transport of this chemical product.

[0007] The most commonly used acrolein production process is based on the gas-phase catalytic oxidation reaction of propylene with atmospheric oxygen. The resulting acrolein can then be directly incorporated into an acrylic acid manufacturing process. When acrolein is used as a raw material for the synthesis of methionine or for fine chemical reactions, a purification section removes the reaction by-products, mainly carbon oxides, acrylic acid, acetic acid, and acetaldehyde.

[0008] The industrial production of acrolein is therefore highly dependent on the raw material propylene, generally obtained by steam cracking or catalytic cracking of petroleum fractions. This raw material of fossil origin also contributes to the increase in the greenhouse effect. It therefore appears necessary to have an acrolein synthesis process that is not dependent on the propylene resource and uses another raw material, preferably renewable. Such a process meets the criteria associated with the concept of green chemistry in the broader framework of sustainable development. In addition, there is a strong market demand for synthetic intermediates such as acrolein, used to obtain many products, to be obtained from bio-sourced raw materials, such as glycerol.

[0009] The term "bio-based" applied to a product means that the product is derived from biomass. It is accepted according to the European standard EN 16935 that the bio-based content of a product can be expressed by measuring its bio-based carbon content. The ASTM D6866 or EN 16640 standards describe such methods for determining the bio-based carbon content in products from the measurement of the content of 14 C.

[0010] It is known, as described in document FR 2882052, that glycerol can lead to the production of acrolein by catalytic dehydration in the gas phase at high temperature. This reaction is accompanied by multiple side reactions which require numerous separation steps or which lead to rapid deactivation of the catalyst.

[0011] Gas-phase methods for preparing acrolein from glycerol require complex catalysts and the vaporization of large quantities of water, resulting in significant energy costs. They generally give average yields, in the order of 60 to 70%, and generate a variety of by-products, which complicates the purification of acrolein, preventing the industrial development of these routes in the past.

[0012] CN 1394839 relates to a process for preparing reuterin from glycerol. Reuterin is defined as 3-hydroxypropionaldehyde (3HPA), 3 HP A hydrates, 3HPA dimers, and 3HPA oligomers. Reaction yields are not given. Acrolein, an intermediate product of the reaction, is obtained by passing pure vaporized glycerol over a potassium sulfate or magnesium sulfate catalyst.

[0013] It has long been known, as described in US 4692027, that reuterin can be obtained from glycerol using microorganisms and that acrolein can be obtained from reuterin in a homogeneous acid medium, for example in the presence of sulfuric acid as described by RH Hall and ES Stem (J. Chem. Soc., 1950, 490-498).

[0014] EP 1669457 describes the fermentation of glycerol into reuterin. The conversion is remarkably high, of the order of 98% as described in Example 2. Example 5 describes the transformation of reuterin into acrolein by the addition of a 35% hydrochloric acid solution to the fermentation medium containing said reuterin. The acrolein obtained remains in the fermentation medium and is directly transformed to obtain other derivatives.

[0015] US 2012 / 0034665 describes a method for obtaining aldehydes by fermentation from glycerol using microorganisms. In Example 11, it is described that acrolein is obtained from a fermentation medium containing reuterin by acid hydrolysis in the presence of hydrochloric acid at elevated temperatures. The acrolein obtained by this method is quantified in the fermentation medium and is not isolated therefrom.

[0016] Thus, even if acrolein is obtained with a high yield, it remains in solution and requires numerous treatments of the reaction medium, such as the neutralization of homogeneous acid catalysts, before being used to make, for example, methionine. These constraints can prevent industrial development. Document EP 3339282 describes the extraction of reuterin from an aqueous solution using chitosan. The disadvantage of this process is that the chitosan must be washed to recover the reuterin, which generates additional volumes of water.

[0017] Document WO 2022 / 073014 describes a process for continuously obtaining acrolein directly from a fermentation medium, by dehydration of reuterin followed by fractional distillation at a pressure below atmospheric pressure and at a temperature between 37°C and 52.4°C to avoid degradation of microbial cells during this operation, which greatly limits the kinetics of the dehydration reaction of reuterin into acrolein and water.

[0018] The publication by S. Oehmke and AP. Zeng (Eng. Life Sci., 2015, 15, 133-139) presents different methods for obtaining acrolein from reuterin. The most efficient is the dehydration of reuterin in the presence of an acid with a HammetHo constant of -1 followed by distillation. This method is described in paragraph 2.3.5 using 500 mL of orthophosphoric acid and 777 mL of fermentation medium containing reuterin.

[0019] Document US 10047381 describes the possibility of obtaining reuterin by fermentation in the absence of glycerol. Example 1 relates to the production of reuterin by fermentation in the absence of carbon sources other than carbon dioxide, not necessarily biosourced. Example 10 does not describe in detail the conditions for converting reuterin into acrolein other than by specifying that this is carried out using acid catalysis.

[0020] The inventors have now surprisingly discovered that it is possible to obtain acrolein from an aqueous solution of reuterin resulting from fermentation after filtration of suspended matter, using a heterogeneous catalytic reactor containing one or more heterogeneous catalysts.

[0021] Accordingly, the invention proposes to provide a simple and easy-to-implement solution for obtaining acrolein from an aqueous solution of reuterin resulting from fermentation. This solution makes it possible to reduce the cost. Summary of the invention

[0022] The proposed technical solution consists of obtaining acrolein from an aqueous solution of reuterin resulting from fermentation after separation of suspended matter, in the presence of a heterogeneous catalyst.

[0023] According to a first aspect, the present invention relates to a process for manufacturing acrolein from an aqueous solution of reuterin resulting from fermentation, said process comprising the following steps:

[0024] - Separate the aqueous solution resulting from fermentation from the suspended matter to obtain an aqueous solution containing reuterin;

[0025] - Introduction of said aqueous solution containing reuterin into a catalytic reactor containing one or more heterogeneous catalysts;

[0026] - Heating said aqueous solution of reuterin in the catalytic reactor in the presence of one or more heterogeneous catalysts to obtain, on the one hand, a gaseous phase mainly consisting of acrolein and, on the other hand, a liquid aqueous phase poor in reuterin and acrolein;

[0027] - Partial or total condensation of said gaseous phase, leading to the production of a condensate rich in acrolein.

[0028] According to one embodiment, the fermentation host for obtaining the aqueous solution of reuterin resulting from fermentation is a bacterium, a yeast, a fungus, an algae, a cyanobacterium or a mixture of several of these elements.

[0029] According to one embodiment, the reuterin contained in the aqueous solution containing the reuterin resulting from fermentation has a biosourced carbon content measured according to the ASTM D6866 or EN 16640 standards greater than or equal to 5%, preferably greater than or equal to 10%, preferably greater than or equal to 25%, preferably greater than or equal to 33%, preferably greater than or equal to 50%, preferably greater than or equal to 66%, preferably greater than or equal to 75%, preferably greater than or equal to 90%, preferably greater than or equal to 95%, preferably greater than or equal to 98%, preferably greater than or equal to 99%, advantageously equal to 100%.

[0030] According to one embodiment of the method according to the invention, the step of separating the suspended matter present in the aqueous solution of reuterin resulting from fermentation, upstream of the step of introduction into the catalytic reactor containing one or more heterogeneous catalysts, is carried out by filtration or centrifugation.

[0031] According to one embodiment, the method according to the invention comprises a step of recovering the suspended matter thus separated by combustion, gasification or spreading.

[0032] According to one embodiment, the aqueous phase low in reuterin and acrolein from the catalytic reactor containing one or more heterogeneous catalysts is recycled totally or partially upstream of the process.

[0033] According to one embodiment, the acrolein-rich condensate is subjected to one or more subsequent purification steps.

[0034] According to a second aspect, the invention relates to acrolein obtained according to the process described above.

[0035] According to one embodiment, the acrolein obtained according to the method is then transformed into methionine and its derivatives. The invention relates to the use of acrolein to obtain methionine and its derivatives.

[0036] According to one embodiment, the acrolein obtained according to the process is then transformed into acrylic acid and its derivatives. The invention relates to the use of acrolein to obtain acrylic acid and its derivatives.

[0037] According to one embodiment, the acrolein obtained according to the method is then transformed into glutaraldehyde and its derivatives. The invention relates to the use of acrolein to obtain glutaraldehyde and its derivatives.

[0038] According to another aspect, the subject of the invention is the acrolein obtained according to this embodiment, that is to say having a biosourced carbon content measured according to the ASTM D6866 or EN 16640 standards greater than or equal to 5%, preferably greater than or equal to 10%, preferably greater than or equal to 25%, preferably greater than or equal to 33%, preferably greater than or equal to 50%, preferably greater than or equal to 66%, preferably greater than or equal to 75%, preferably greater than or equal to 90%, preferably greater than or equal to 95%, preferably greater than or equal to 98%, preferably greater than or equal to 99%, advantageously equal to 100%. The invention also relates to the various downstream applications of this acrolein having a biosourced carbon content. The present invention meets the need expressed in the state of the art.It allows acrolein to be generated from an aqueous solution of reuterin resulting from fermentation without using a strong homogeneous acid or a complex process.

[0039] The invention will now be described in more detail in the following description. The attached Figure 1 illustrates the principle diagram of a particular embodiment of the method according to the invention.

[0040] Detailed description of the invention

[0041] The invention aims to produce acrolein on an industrial scale from an aqueous solution of reuterin resulting from fermentation, after separation of the suspended matter, using a simple and easy-to-implement process, in particular avoiding the use of homogeneous acid catalysts.

[0042] The invention consists of producing acrolein on an industrial scale from an aqueous solution of reuterin resulting from fermentation by heating said solution in a heterogeneous catalytic reactor, after separation of the suspended matter, thus generating a gaseous phase mainly composed of acrolein which is condensed to give a condensate rich in acrolein.

[0043] According to the invention, said process for obtaining acrolein comprises the following steps which can be carried out sequentially or simultaneously, each in a batch, semi-batch, continuous or semi-continuous manner:

[0044] - Separation of the aqueous solution of reuterin resulting from fermentation of suspended matter by a liquid-solid separation method to obtain an aqueous solution containing reuterin free from suspended matter,

[0045] - Introduction of said aqueous solution containing reuterin free of suspended matter into a heterogeneous catalytic reactor containing one or more heterogeneous catalysts;

[0046] - Heating said aqueous solution containing reuterin free of suspended matter in the catalytic reactor containing one or more heterogeneous catalysts to obtain, on the one hand, a gaseous phase mainly consisting of acrolein and, on the other hand, a liquid aqueous phase poor in reuterin and acrolein;

[0047] - Partial or total condensation of said gaseous phase, leading to the production of a condensate rich in acrolein. According to various embodiments, said process comprises the following characteristics, possibly combined. The contents indicated are expressed by weight, unless otherwise indicated. Within the ranges of values ​​indicated, the limits are included.

[0048] Optionally, the method according to the invention may include one or more additional steps, which may be carried out sequentially or simultaneously, each in a batch, semi-batch, continuous or semi-continuous manner, such as:

[0049] - Recovery of these separated suspended materials;

[0050] - Recycling of the liquid aqueous phase low in reuterin and acrolein from the reactor upstream of the process;

[0051] - Purification of the acrolein-rich condensate.

[0052] According to one embodiment, the reuterin content of the aqueous reuterin solution resulting from fermentation varies between 0.1% and 10%, preferably between 1.5% and 5%.

[0053] According to one embodiment, the pH of the aqueous solution of reuterin resulting from fermentation varies from 3 to 12, preferably from 4 to 7.

[0054] According to one embodiment, the content of suspended matter in the aqueous solution of reuterin resulting from fermentation varies between 0.1% and 5%, preferably between 0.5% and 1%.

[0055] There are different methods for separating liquid and solid phases. The two most common technologies are filtration and centrifugal separation.

[0056] According to one embodiment, the separation of suspended matter is carried out by filtration with filters having a pore size between 0.01 and 0.9 μm.

[0057] According to one embodiment, the separation of suspended matter is carried out by filtration at a temperature varying from 20°C to 50°C, preferably from 25°C to 40°C.

[0058] The filters often used in these separations are so-called tangential filters. This tangential filtration is the preferred method because the membranes used for tangential filtration have a long service life and can be regenerated in the process. The membranes used for this type of filtration are generally made of polymer materials. Their disadvantage is that they cannot withstand basic pH values ​​(pH >12) due to sodium hydroxide during membrane cleaning operations. In fact, ceramic or graphite membranes are preferably used. The filtration carried out is tangential microfiltration on flat, cartridge, tubular or multi-tubular modules and preferably with multi-channel tubular modules.

[0059] According to one embodiment, the separation of suspended matter is carried out by centrifugation, for example by separation technology involving a plate separator.

[0060] According to one embodiment, the separation of suspended matter is carried out by centrifugation at a temperature varying from 20°C to 80°C, preferably from 25°C to 40°C.

[0061] According to one embodiment, the suspended matter once separated is recovered by hydrothermal gasification.

[0062] According to one embodiment, the gas resulting from gasification is composed of 40-70% methane, 5-20% hydrogen and 20-40% carbon dioxide.

[0063] According to one embodiment, the suspended matter is mixed with the water required for the hydrothermal treatment before introduction into the gasification.

[0064] Depending on the embodiment, hydrothermal gasification is carried out at a temperature between 350°C and 450°C and a pressure of 25 MPa.

[0065] According to one embodiment of the invention, the aqueous solution containing reuterin free of suspended matter has a reuterin content of between 0.1% and 10%, preferably between 1.5% and 5%.

[0066] According to one embodiment, the aqueous solution containing reuterin free of suspended matter is preheated before introduction into the heterogeneous catalytic reactor using one or more tubular or spiral exchangers in series.

[0067] According to one embodiment, the preheating of the aqueous solution containing reuterin free of suspended matter is done by electricity, steam, by a heat transfer fluid such as mineral oil or by recycling the aqueous phase poor in reuterin and acrolein from the heterogeneous catalytic reactor containing one or more heterogeneous catalysts.

[0068] According to one embodiment, the heterogeneous catalysts used are ion exchange acid resins such as Amberlyst or Dowex resins, zeolites, heteropolyacids or Nafion resins.

[0069] According to one embodiment, the heterogeneous catalyst used is an acid resin. According to one embodiment, the heterogeneous catalyst used is a zeolite.

[0070] According to another embodiment, the heterogeneous catalyst is a bio-catalyst such as supported enzymes.

[0071] According to one embodiment, the heterogeneous catalyst is a supported lipase.

[0072] There are multiple choices of heterogeneous catalytic reactor technologies that can be implemented: fixed bed, moving bed, suspended bed, fluidized bed.

[0073] According to one embodiment, the heterogeneous catalytic reactor is a moving bed reactor.

[0074] According to one embodiment, the heterogeneous catalytic reactor is a suspended bed reactor.

[0075] According to one embodiment, the heterogeneous catalytic reactor is a fluidized bed reactor.

[0076] According to one embodiment, the heterogeneous catalytic reactor is a fixed bed reactor.

[0077] According to one embodiment, the catalyst bed of the heterogeneous catalytic reactor is crossed by the liquid in a descending manner.

[0078] According to one embodiment, the catalyst bed of the heterogeneous catalytic reactor is crossed by the liquid in an ascending manner.

[0079] According to one embodiment, the residence time in the heterogeneous catalytic reactor is between 0.2 h and 3 h, preferably between 0.5 h and 2 h.

[0080] According to one embodiment, the heterogeneous catalytic reactor comprises a recirculation loop

[0081] According to one embodiment, the flow rate of the recirculation loop expressed as the mass ratio of the flow rate sent into the loop to the liquid flow rate withdrawn from the reactor is between 3 and 15, preferably between 5 and 10.

[0082] According to one embodiment, the residence time in the heterogeneous catalytic reactor for each pass of the recirculated flow on the fixed bed varies between 5 and 12 minutes.

[0083] According to one embodiment, the temperature in the heterogeneous catalytic reactor is between 37°C and 150°C, preferably between 37°C and 100°C. This temperature can be controlled by means of temperature sensors placed in the reactor. There are multiple choices of technologies that can be implemented for heating the heterogeneous catalytic reactor: double jacket, half-shell or quilted double jacket. The heating system can also consist of an exchanger installed on an external recirculation loop.

[0084] According to one embodiment, the heating of the heterogeneous catalytic reactor is carried out by a double jacket, half-shell or quilted double jacket.

[0085] According to one embodiment, the heating of the heterogeneous catalytic reactor is carried out by an exchanger installed on an external recirculation loop.

[0086] According to one embodiment, the agitation of the catalytic reactor is carried out by the recirculation loop.

[0087] According to one embodiment, the pressure in the heterogeneous catalytic reactor is between 0.04 MPa and 0.5 MPa, preferably between 0.04 MPa and 0.1 MPa.

[0088] According to one embodiment, the heterogeneous catalytic reactor is operated in batch or semi-batch.

[0089] According to one embodiment, the heterogeneous catalytic reactor is operated continuously or semi-continuously.

[0090] According to one embodiment, the condensation of the gaseous phase mainly consisting of acrolein from the heterogeneous catalytic reactor is carried out by adjusting the condensation temperature by placing one or more condensers in series.

[0091] According to one embodiment, the condensation of the gaseous phase mainly consisting of acrolein from the heterogeneous catalytic reactor is carried out using one or more tubular or spiral exchangers in series.

[0092] According to one embodiment, there is no addition of inhibitor to the condensation step.

[0093] According to one embodiment, one or more polymerization inhibitors are added to the condensation step.

[0094] According to one embodiment, the polymerization inhibitors used in the process according to the invention are chosen from the inhibitors conventionally used in existing industrial processes for the production of acrolein. These include phenolic derivatives such as hydroquinone (HQ) and its derivatives such as hydroquinone methyl ether (EMHQ), 2,6-di-terbutyl-4-methyl phenol (BHT) or 2,4-dimethyl-6-terbutyl phenol (Topanol A); phenothiazine and its derivatives; nitroxide compounds such as 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (4-OH-TEMPO); amine compounds such as paraphenylenediamine derivatives; copper and manganese salts known for their polymerization inhibitor properties.

[0095] According to a preferred embodiment, at least one of said polymerization inhibitors is hydroquinone (HQ).

[0096] According to one embodiment, the liquid aqueous phase low in reuterin and acrolein from the heterogeneous catalytic reactor is recycled at least partially upstream of the process.

[0097] According to one embodiment, this liquid aqueous phase low in reuterin and acrolein is cooled in an exchanger before being recycled.

[0098] According to one embodiment, this exchanger is also supplied counter-currently by the aqueous solution containing reuterin free from suspended matter supplying the heterogeneous catalytic reactor.

[0099] According to one embodiment, the recycled liquid aqueous phase is cooled to a temperature between 20°C and 40°C, preferably between 30°C and 37°C, then injected upstream of the fermentation reactor with or without make-up water containing part of the inorganic salts and other materials necessary for the fermentation.

[0100] According to one embodiment, a portion of the recycled liquid aqueous phase is purged to a combustion or gasification treatment system.

[0101] According to one embodiment, the purge rate relative to the total flow rate of the recycling of the liquid aqueous phase varies between 0.1% and 1%, preferably between 0.3% and 0.8%.

[0102] According to one embodiment, the acrolein-rich condensate obtained after condensation is purified. The purification operations may include distillations, liquid / liquid extractions, separations using a film evaporator, or crystallizations.

[0103] According to one embodiment, the purification is carried out by at least one distillation column.

[0104] According to one embodiment, the purification is carried out in a column above the heterogeneous catalytic reactor.

[0105] According to one embodiment, the reaction and purification are carried out in a reactive distillation column. According to one embodiment, the steps of recovering the separated suspended matter, recycling the liquid aqueous phase low in reuterin and acrolein from the heterogeneous catalytic reactor or purifying the acrolein-rich condensate are each carried out in batch, semi-batch, continuous or semi-continuous mode.

[0106] According to one embodiment of the method according to the invention, the reuterin contained in the aqueous solution of reuterin resulting from fermentation has a biosourced carbon content measured according to the ASTM D6866 or EN 16640 standards greater than or equal to 5%, preferably greater than or equal to 10%, preferably greater than or equal to 25%, preferably greater than or equal to 33%, preferably greater than or equal to 50%, preferably greater than or equal to 66%, preferably greater than or equal to 75%, preferably greater than or equal to 90%, preferably greater than or equal to 95%, preferably greater than or equal to 98%, preferably greater than or equal to 99%, advantageously equal to 100%.

[0107] According to another aspect, the subject of the invention is acrolein obtained according to this embodiment and containing a biosourced carbon content measured according to the ASTM D6866 or EN 16640 standards greater than or equal to 5%, preferably greater than or equal to 10%, preferably greater than or equal to 25%, preferably greater than or equal to 33%, preferably greater than or equal to 50%, preferably greater than or equal to 66%, preferably greater than or equal to 75%, preferably greater than or equal to 90%, preferably greater than or equal to 95%, preferably greater than or equal to 98%, preferably greater than or equal to 99%, advantageously equal to 100% and its various downstream applications.

[0108] The invention also relates to the use of acrolein containing a bio-sourced carbon content for the manufacture of methionine as well as its derivatives having a bio-sourced carbon content originating at least in part from the bio-sourced carbon content of acrolein.

[0109] The invention also relates to the use of acrolein containing a bio-sourced carbon content for the manufacture of glutaraldehyde as well as its derivatives having a bio-sourced carbon content originating at least in part from the bio-sourced carbon content of acrolein. The invention also relates to the use of acrolein containing a bio-sourced carbon content for the manufacture of acrylic acid as well as its derivatives having a bio-sourced carbon content originating at least in part from the bio-sourced carbon content of acrolein.

[0110] According to a particular embodiment corresponding to Figure 1, the process for manufacturing acrolein can then be described as follows:

[0111] The aqueous solution of reuterin resulting from fermentation (2) is produced in a fermentation reactor RI and feeds a solid-liquid separator SI which makes it possible to obtain the separated suspended matter (3) and the aqueous solution containing reuterin free of suspended matter (4). The solution (4) is preheated in an exchanger E1 before being introduced into the heterogeneous catalytic reactor R2. The reactor R2 generates on the one hand a gaseous phase mainly composed of acrolein (5) and a liquid aqueous phase poor in reuterin and acrolein (9). The gaseous phase mainly composed of acrolein (5) is totally or partially condensed by a condenser C1, to give a condensant rich in acrolein (7) and possibly a stream (8) which can be recycled into the heterogeneous catalytic reactor.This condensation includes the addition of a solution containing polymerization inhibitors (6) to the condenser CL. The acrolein-rich condensant (7) can be subjected in a subsequent step to one or more additional purification operations. The heterogeneous catalytic reactor R2 is equipped with a fixed bed of acidic ion exchange resins through which the liquid flows upwards. It is stirred by a recirculation loop (17) equipped with a heating system. The liquid aqueous phase poor in reuterin and acrolein (9) from the heterogeneous catalytic reactor R2 is divided between a flow (10) and a flow (11). The flow (11) is used to preheat the flow (4) using the exchanger EL. After this heat exchange, (11) is introduced upstream of the fermentation reactor RI and serves as a water make-up in addition to the flow (1) which contains all the elements necessary to carry out the fermentation.The separated suspended matter (3) and the flow (10) feed a gasifier G1 making it possible to upgrade the flow containing the separated suspended matter (3) into gas (16), salt (15) and water (12). The water produced can be recycled totally or partially upstream of the gasifier G1 (13). The water produced in the gasifier G1 can be purged by the flow (14). The examples below illustrate the present invention without, however, limiting its scope.

[0112] EXPERIMENTAL PART

[0113] The pH of the various aqueous solutions was measured using a Mettler Toledo Five Easy Plus immersion probe device.

[0114] Reuterin titers were determined by the colorimetric method adapted from S. Vollenweider et al. in J. Agric Food Chem, 2003, 51, 3287-3293.

[0115] The tests of the various comparative examples are carried out in a laboratory setup. A three-necked flask was used, it is equipped with magnetic stirring. The side neck of the flask is equipped with a thermometer to monitor the reaction temperature. The upper neck of the flask is equipped with a separation bridge leading to a water-cooled side condenser, itself leading to a recipe consisting of a second 50 mL flask. The reuterin solution from a fermentation used in the examples was obtained from glycerol and has a bio-based carbon content measured according to ASTM D6866 greater than 95%. It was previously filtered to obtain the aqueous solution containing reuterin free of suspended matter, whose bio-based carbon content measured according to ASTM D6866 is greater than 95%.

[0116] The acrolein obtained in the examples has a bio-sourced carbon content measured according to ASTM D6866 of greater than 95%.

[0117] EXAMPLE 1 (comparative): Use of an aqueous solution containing reuterin free of suspended matter without the addition of homogeneous acid.

[0118] 200 g of aqueous solution containing reuterin free of suspended matter with a reuterin content of 1.2% and a pH of 6.9 were introduced into a stirred three-necked flask equipped with a separating bridge and heated to a simmer at atmospheric pressure for 2 h. The resulting gas phase was condensed to obtain 0.45 g of acrolein, which corresponds to a yield of 24%. The resulting liquid aqueous phase contains 0.6% reuterin and 0.2% acrolein and has a pH of 6.9. EXAMPLE 2 (comparative): Use of an aqueous solution containing reuterin free of suspended matter with the addition of homogeneous acid.

[0119] 200 g of aqueous solution containing reuterin free of suspended matter at a reuterin titer of 1.2% and pH 6.9 were introduced into a stirred three-necked flask equipped with a separating bridge. 2.4 g of sulfuric acid were added to the reaction medium; the pH measured after addition of sulfuric acid was 1.2. The medium was heated to simmering at atmospheric pressure for 2 h. The resulting gas phase was condensed to obtain 1.67 g of acrolein, which corresponds to a yield of 92%. The resulting liquid aqueous phase contains traces of reuterin (<0.01%) and 0.06% of acrolein and has a pH of 1.2.

[0120] EXAMPLE 3 (according to the invention): Use of the aqueous solution containing reuterin free of suspended matter in the presence of ion exchange resins.

[0121] 200 g of aqueous solution containing reuterin free of suspended matter at a reuterin content of 1.2% and with a measured pH of 6.9 were introduced into a stirred three-necked flask equipped with a distillation bridge. 3 g of Amberlyst Al 31 acid ion exchange resins were added to the reaction medium and the medium was then heated to a simmer for two hours. The measured pH after addition of the resin was 6.1. The medium was heated to a simmer at atmospheric pressure for two hours. The vapors were condensed using a distillation bridge to obtain 1.71 g of acrolein, which corresponds to a yield of 94%. The resulting liquid aqueous phase contains 0.06% reuterin and traces (<0.01%) of acrolein and has a measured pH of 5.9.

Claims

CLAIMS 1. A process for manufacturing acrolein from an aqueous solution of reuterin obtained from fermentation, said process comprising the following steps: - Separation of suspended matter from said aqueous solution of reuterin resulting from fermentation to obtain an aqueous solution containing reuterin free from suspended matter, - Introduction of said aqueous solution containing reuterin free of suspended matter into a heterogeneous catalytic reactor containing one or more heterogeneous catalysts, - Heating said solution in said reactor to obtain on the one hand a gaseous phase composed mainly of acrolein and, on the other hand, a liquid aqueous phase poor in reuterin and acrolein, - Condensation of said gaseous phase to obtain a condensate rich in acrolein.

2. Method according to claim 1, wherein the reuterin solution resulting from fermentation has a reuterin content of between 0.1% and 10%, preferably between 1.5% and 5%.

3. Method according to claim 1 or 2, in which the aqueous solution of reuterin resulting from fermentation has a pH between 3 and 12, preferably between 4 and 7.

4. A method according to any one of the preceding claims, wherein the separation of suspended matter from said aqueous solution of reuterin resulting from fermentation is carried out by filtration.

5. A method according to any one of claims 1 to 4, wherein the separation of suspended matter from said aqueous solution of reuterin resulting from fermentation is carried out by centrifugation.

6. A method according to any preceding claim, wherein the heterogeneous catalyst is an acidic ion exchange resin.

7. Process according to any one of claims 1 to 5, in which the heterogeneous catalyst is a zeolite.

8. A method according to any one of claims 1 to 5, wherein the heterogeneous catalyst is a supported enzyme.

9. Method according to any one of the preceding claims, in which the heterogeneous catalytic reactor used is a fixed bed reactor.

10. Method according to any one of the preceding claims, in which the bed of the heterogeneous catalytic reactor is crossed by the liquid in a descending manner.

11. Method according to any one of claims 1 to 9, in which the bed of the heterogeneous catalytic reactor is crossed by the liquid in an ascending manner.

12. A method according to any one of the preceding claims, wherein the heterogeneous catalytic reactor operates at temperatures ranging from 37°C to 150°C, preferably between 37°C and 100°C.

13. Process according to any one of the preceding claims, in which the heterogeneous catalytic reactor operates with a residence time between 0.2 h and 3 h, preferably between 0.5 h and 2 h.

14. A method according to any one of the preceding claims, wherein the aqueous solution containing reuterin free of suspended matter is preheated before being introduced into the heterogeneous catalytic reactor using one or more tubular or spiral exchangers in series.

15. Method according to any one of the preceding claims, in which the heterogeneous catalytic reactor is equipped with a recirculation loop.

16. Method according to any one of the preceding claims comprising a step of recovering the suspended matter after separation by combustion, gasification or spreading.

17. Process according to any one of the preceding claims, comprising a step of recycling upstream of the process at least part of the aqueous phase poor in reuterin and acrolein obtained at the outlet of the heterogeneous catalytic reactor.

18. Method according to any one of the preceding claims, comprising a step of purifying the acrolein-rich condensate obtained after condensation.

19. Method according to any one of the preceding claims, in which the different steps are each carried out in batch, semi-batch, continuous or semi-continuous mode.

20. Acrolein obtained by the process according to any one of the preceding claims.

21. Use of acrolein according to claim 20 for the manufacture of methionine and its derivatives.

22. Use of acrolein according to claim 20 for the manufacture of glutaraldehyde and its derivatives.

23. Use of acrolein according to claim 20 for the manufacture of acrylic acid and its derivatives.

24. Method according to any one of claims 1 to 19, in which the reuterin contained in the aqueous solution of reuterin resulting from fermentation has a biosourced carbon content, measured according to the ASTM D6866 or EN 16640 standards, greater than or equal to 5%.

25. Acrolein obtained according to the process of claim 24 having a biosourced carbon content, measured according to ASTM D6866 or EN 16640 standards, greater than or equal to 5%.

26. Use of acrolein according to claim 25 for the manufacture of methionine and its derivatives.

27. Use of acrolein according to claim 25 for the manufacture of glutaraldehyde and its derivatives.

28. Use of acrolein according to claim 25 for the manufacture of acrylic acid and its derivatives.

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