PROCESS FOR THE MANUFACTURE OF ACROLIN

Abstract

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 reuterin into acrolein without the addition of acid in a reactor under pressure greater than atmospheric pressure. The acrolein produced in 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 in the context 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. Figure 1

Description

Title of the invention: PROCESS FOR PRODUCING ACROLIN Technical field

[0001] The present invention relates to a process for manufacturing 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 acid in a pressurized reactor. 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 manufacture 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-sourced carbon within the meaning of ASTM D6866 or EN 16640 standards when bio-sourced raw materials are used to obtain the aqueous solution of reuterin derived from fermentation. Prior art and technical problem

[0002] Acrolein is the simplest of the unsaturated aldehydes. It is also called 2-propenal, acrylaldehyde or acrylic aldehyde. By its structure, acrolein has a high reactive power thanks to the presence of two reactive functions which are capable of reacting individually or together. This is why acrolein finds numerous applications, notably 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.

[0003] 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.

[0004] The most commonly used acrolein production process is based on the gas-phase catalytic oxidation reaction of propylene with atmospheric oxygen. The acrolein thus obtained can then be directly integrated into a process for manufacturing acrylic acid. When acrolein is used as a raw material for the synthesis of methionine or for fine chemical reactions, a section of Purification removes by-products of the reaction, mainly carbon oxides, acrylic acid, acetic acid and acetaldehyde.

[0005] 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 a process for synthesizing acrolein 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 context of sustainable development. In addition, there is a strong market demand for synthetic intermediates such as acrolein, used to obtain numerous products, to be able to be obtained from bio-sourced raw materials, such as glycerol.

[0006] The term "bio-sourced" applied to a product means that the said product is derived from biomass. It is accepted according to the European standard EN 16935 that the bio-sourced content of a product can be expressed by measuring its bio-sourced carbon content. The standards ASTM D6866 or EN 16640 describe such methods for determining the bio-sourced carbon content in products from the measurement of the 14C content.

[0007] 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.

[0008] Gas-phase methods for preparing acrolein from glycerol require complex catalysts and the vaporization of large quantities of water, which results in a significant energy cost. They generally give average yields, of the order of 60 to 70%, and generate a variety of by-products, which complicates the purification of acrolein, preventing the industrial development of said routes in the past.

[0009] Document CN 1394839 relates to a process for preparing reuterin from glycerol. Reuterin is defined as 3-hydroxypropionaldehyde (3HPA), 3HPA hydrates, 3HPA dimers and 3HPA oligomers. The yields of the reaction are not given. Acrolein, an intermediate product of the reaction, is obtained by passing pure vaporized glycerol over a catalyst of the potassium sulfate or magnesium sulfate type.

[0010] 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, by example in the presence of sulfuric acid as described by RH Hall and ES Stern (J. Chem. Soc., 1950, 490-498).

[0011] Document 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% solution of hydrochloric acid into the fermentation medium containing said reuterin. The acrolein obtained remains in the fermentation medium and is directly transformed to obtain other derivatives.

[0012] Document 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.

[0013] 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.

[0014] Document EP 3339282 describes the extraction of reuterin from an aqueous solution using chitosan. The disadvantage of this method is that the chitosan must be washed in order to recover the reuterin, which generates additional volumes of water.

[0015] 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.

[0016] 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 having a Hammet constant Ho 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.

[0017] 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 bio-sourced. 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.

[0018] The inventors have now surprisingly discovered that it is possible to obtain acrolein from an aqueous solution of reuterin resulting from fermentation without adding a strong acid catalyst by working in a reactor operating at a pressure higher than atmospheric pressure.

[0019] Consequently, 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

[0020] The proposed technical solution consists of obtaining acrolein from an aqueous solution of reuterin resulting from fermentation by heating said aqueous solution in a pressurized reactor.

[0021] 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:

[0022] - Introduction of said aqueous solution of reuterin into a reactor operating under a pressure greater than atmospheric pressure;

[0023] - Heating said aqueous reuterin solution in the reactor under pressure higher than atmospheric pressure to obtain, on the one hand, a gaseous phase mainly made up of acrolein and, on the other hand, a liquid aqueous phase poor in reuterin and acrolein;

[0024] - Partial or total condensation of said gaseous phase, leading to the obtaining of a condensate rich in acrolein.

[0025] 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.

[0026] According to one embodiment, 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%.

[0027] According to one embodiment, the method according to the invention comprises a step of separating the suspended matter possibly present in the aqueous solution of reuterin resulting from fermentation, upstream of the step of introduction into the reactor under pressure greater than atmospheric pressure, for example by filtration or centrifugation.

[0028] 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.

[0029] According to one embodiment, the aqueous phase low in reuterin and acrolein from the pressurized reactor is recycled totally or partially upstream of the process.

[0030] According to one embodiment, the acrolein-rich condensate is subjected to one or more subsequent purification steps.

[0031] According to a second aspect, the invention relates to acrolein obtained according to the process described above.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] According to one embodiment, the acrolein obtained according to the process 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 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.

[0036] The present invention meets the need expressed in the state of the art. It makes it possible to generate acrolein from an aqueous solution of reuterin resulting from fermentation without using a strong acid or a complex process.

[0037] The invention will now be described in more detail in the following description. The attached [Fig.l] illustrates the principle diagram of a particular embodiment of the method according to the invention. Detailed description of the invention

[0038] The invention aims to produce acrolein on an industrial scale from an aqueous solution of reuterin resulting from fermentation, using a simple and easy-to-implement process, in particular avoiding the use of acid catalysts.

[0039] The invention consists in producing acrolein on an industrial scale from an aqueous solution of reuterin resulting from fermentation by heating said solution in a reactor operating at a pressure higher than atmospheric pressure, thus generating a gaseous phase mainly composed of acrolein which is condensed to give a condensate rich in acrolein.

[0040] 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:

[0041] - Introduction of an aqueous solution of reuterin resulting from fermentation into a reactor designed to operate at pressures greater than atmospheric pressure;

[0042] - Heating said aqueous solution of reuterin resulting from fermentation under a pressure higher than atmospheric pressure to obtain, on the one hand, a gaseous phase mainly made up of acrolein and, on the other hand, a liquid aqueous phase poor in reuterin and acrolein;

[0043] - Partial or total condensation of said gaseous phase, leading to the obtaining of a condensate rich in acrolein.

[0044] According to various embodiments, said method comprises the following characteristics, where appropriate combined. The contents indicated are expressed by weight, unless otherwise indicated. Within the ranges of values indicated, the limits are included.

[0045] 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:

[0046] - Separation upstream of the reactor of suspended matter present in the aqueous solution of reuterin resulting from fermentation;

[0047] - Recovery of these separated suspended materials;

[0048] - Recycling of the liquid aqueous phase poor in reuterin and acrolein from the reactor upstream of the process;

[0049] - Purification of the acrolein-rich condensate.

[0050] 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%.

[0051] 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.

[0052] According to one embodiment, the aqueous solution of reuterin resulting from fermentation is preheated before introduction into the reactor using one or more tubular or spiral exchangers in series.

[0053] According to one embodiment, the preheating of the aqueous solution of reuterin resulting from fermentation 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 resulting from the pressurized reactor.

[0054] According to one embodiment, the pressure reactor is equipped with a heating system and agitation by a pump and external recirculation through an exchanger. It can also be heated or cooled by double jacket, half-shell or quilted double jacket. To increase the heating power, this reactor can also include internal coils or baffles.

[0055] Optionally, the agitation can be axial flow, radial flow or combined dual flow.

[0056] According to one embodiment, the temperature in the pressurized reactor is between 100°C and 250°C, preferably from 120°C to 180°C. This temperature can be controlled by means of temperature sensors placed in the reactor.

[0057] According to one embodiment, the pressure in the pressurized reactor is between 0.1 MPa and 2.0 MPa, preferably between 0.15 MPa and 1.7 MPa.

[0058] According to one embodiment, the residence time in the pressurized reactor is between 0.2 h and 3 h, preferably between 0.5 h and 1 h.

[0059] According to one embodiment, the reaction under pressure is carried out in batch or semi-batch.

[0060] According to one embodiment, the reaction under pressure is carried out continuously or semi-continuously.

[0061] According to one embodiment, the condensation of the gaseous phase mainly consisting of acrolein resulting from the reaction is carried out by adjusting the condensation temperature carried out by placing one or more condensers in series.

[0062] According to one embodiment, the condensation of the gaseous phase mainly consisting of acrolein resulting from the reaction is carried out using one or more tubular or spiral exchangers in series.

[0063] According to one embodiment, there is no addition of inhibitor to the condensation step.

[0064] According to one embodiment, one or more polymerization inhibitors are added to the condensation step.

[0065] 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.

[0066] According to a preferred embodiment, at least one of said polymerization inhibitors is hydroquinone (HQ).

[0067] According to one embodiment, the aqueous solution of reuterin resulting from fermentation is first subjected to a separation step to remove suspended matter before being introduced into the pressurized reactor. There are different methods for separating the liquid and solid phases. The two most common technologies are filtration and centrifugal separation.

[0068] 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%.

[0069] 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.

[0070] According to one embodiment, the separation of the suspended matter is carried out by filtration at a temperature varying from 20°C to 50°C, preferably from 25°C to 40°C.

[0071] 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 polymer materials. Their disadvantage is that they cannot withstand basic pH values (pH >12) due to soda during membrane cleaning operations. In fact, ceramic or graphite membranes are preferably used. The filtration carried out is a tangential microfiltration on flat, cartridge, tubular or multi-tubular modules and preferably with multi-channel tubular modules.

[0072] According to one embodiment, the separation of suspended matter is carried out by centrifugation, for example by separation technology involving a plate separator.

[0073] According to one embodiment, the separation of the suspended matter is carried out by centrifugation at a temperature varying from 20°C to 80°C, preferably from 25°C to 40°C.

[0074] According to one embodiment, the suspended materials once separated are recovered by hydrothermal gasification.

[0075] According to one embodiment, the gas resulting from the gasification is composed of 40-70% methane, 5-20% hydrogen and 20-40% carbon dioxide.

[0076] According to one embodiment, the suspended materials are mixed with the water necessary for the hydrothermal treatment before introduction into the gasification.

[0077] According to the embodiment, the hydrothermal gasification is carried out at a temperature between 350°C and 450°C and a pressure of 25 MPa.

[0078] According to one embodiment, the liquid aqueous phase low in reuterin and acrolein from the pressurized reactor is recycled at least partially upstream of the process.

[0079] According to one embodiment, this liquid aqueous phase is cooled in an exchanger before being recycled.

[0080] According to one embodiment, this exchanger is also supplied counter-currently by the aqueous solution of reuterin resulting from a fermentation supplying the reactor under pressure.

[0081] 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 a portion of the inorganic salts and other materials necessary for the fermentation.

[0082] According to one embodiment, a portion of the recycled liquid aqueous phase is purged to a treatment system by combustion or by gasification.

[0083] 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%.

[0084] 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.

[0085] According to one embodiment, the steps of separating the suspended matter, recovering the separated suspended matter, recycling the liquid aqueous phase from the dehydration reactor or purifying the acrolein-rich condensate are each carried out in batch, semi-batch, continuous or semi-continuous mode.

[0086] 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%.

[0087] 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 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.

[0088] The invention also relates to the use of acrolein containing a biosourced carbon content for the manufacture of methionine as well as its derivatives having a biosourced carbon content originating at least in part from the biosourced carbon content of acrolein.

[0089] The invention also relates to the use of acrolein containing a biosourced carbon content for the manufacture of glutaraldehyde as well as its derivatives having a biosourced carbon content originating at least in part from the biosourced carbon content of acrolein.

[0090] The invention also relates to the use of acrolein containing a biosourced carbon content for the manufacture of acrylic acid as well as its derivatives having a biosourced carbon content originating at least in part from the biosourced carbon content of acrolein.

[0091] According to a particular embodiment corresponding to [Fig. 1], the process for manufacturing acrolein can then be described as follows:

[0092] The aqueous solution of reuterin resulting from a 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 of reuterin resulting from a fermentation without suspended matter (4). The aqueous solution of reuterin resulting from a fermentation without suspended matter (4) is preheated in an exchanger E1 before being introduced into the pressurized reactor R2. The reactor under pressure 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 condensed totally or partially by a condenser Cl, to give a condensant rich in acrolein (7) and possibly a stream (8) which can be recycled in the pressure reactor. This condensation comprises the addition of a solution containing polymerization inhibitors (6) on the condenser Cl. The condensant rich in acrolein (7) can be subjected in a subsequent step to one or more additional purification operations. The liquid aqueous phase poor in reuterin and acrolein (9) from the pressure reactor R2 is divided between a stream (10) and a stream (11).The flow (11) is used to preheat the flow (4) and, after this heat exchange, is recycled upstream of the fermentation reactor RI and serves as a water supplement 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).

[0093] The following examples illustrate the present invention without, however, limiting its scope. EXPERIMENTAL PART

[0094] The pH of the different aqueous solutions was measured using a Mettler Toledo Five Easy Plus immersion probe device.

[0095] Reuterin titers were determined by the colorimetric method adapted from S. Vollenweider et al. (J. Agric Food Chem, 2003, 51, 3287-3293).

[0096] 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.

[0097] The reuterin solution from fermentation used in the examples was obtained from glycerol and has a biosourced carbon content measured according to ASTM D6866 of greater than 95%.

[0098] The acrolein obtained in the examples has a biosourced carbon content measured according to the ASTM D6866 standard greater than 95%.

[0099] EXAMPLE 1 (comparative): Use of an aqueous solution of reuterin resulting from fermentation without the addition of acid and at atmospheric pressure.

[0100] 200 g of aqueous solution of reuterin from fermentation at a titer of 1.2% reuterin and pH 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, corresponding 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.

[0101] EXAMPLE 2 (comparative): Use of an aqueous solution of reuterin resulting from fermentation with the addition of acid and at atmospheric pressure.

[0102] 200 g of aqueous solution of reuterin from fermentation at a titer of 1.2% reuterin 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% acrolein and has a pH of 1.2.

[0103] EXAMPLE 3 (comparative): Use of an aqueous solution of reuterin resulting from fermentation without the addition of acid and at pressure lower than atmospheric pressure.

[0104] 200 g of aqueous solution of reuterin from fermentation at a titer of 1.2% reuterin and pH 6.9 were introduced into a stirred three-necked flask equipped with a separation bridge, followed by a liquid nitrogen trap. The stirred flask was heated to 42 °C under 0.062 MPa for 2 h. The resulting gas phase was condensed using the liquid nitrogen trap to obtain 0.16 g of acrolein, corresponding to a yield of 9%. The resulting liquid aqueous phase contains 1.06% reuterin and 0.02% acrolein and has a pH of 6.9.

[0105] EXAMPLE 4 (according to the invention): Use of an aqueous solution of reuterin resulting from fermentation without the addition of acid and at a pressure higher than atmospheric pressure (0.2 MPa).

[0106] 200 g of aqueous solution of reuterin from fermentation at a titer of reuterine of 1.2% and whose pH is 6.9 were introduced into an autoclave reactor with mechanical stirring and equipped with a cooled separation bridge connected to a container to receive the condensate.

[0107] The autoclave under a pressure of 0.2 MPa is heated to 120 °C for 1 h. The resulting gas phase was condensed to obtain 1.23 g of acrolein, which corresponds to a yield of 67%. The resulting liquid aqueous phase contains 0.3% reuterin and 0.07% acrolein and has a pH of 6.9.

[0108] EXAMPLE 5 (according to the invention): Use of an aqueous solution of reuterin resulting from fermentation without the addition of acid and at a pressure higher than atmospheric pressure (0.5 MPa).

[0109] 200 g of aqueous solution of reuterin from fermentation at a titer of reuterine of 1.2% and whose pH is 6.9 were introduced into an autoclave reactor with mechanical stirring and equipped with a cooled separation bridge connected to a container to receive the condensate.

[0110] The autoclave under a pressure of 0.5 MPa is heated to 150 °C for 1 h. The resulting gas phase was condensed to obtain 1.71 g of acrolein, which corresponds to a yield of 94%. The resulting liquid aqueous phase contains 0.06% of reuterin and traces (<0.01%) of acrolein and has a pH of 6.9.

Claims

Claims

1. A process for manufacturing acrolein from an aqueous solution of reuterin obtained from fermentation, said process comprising the following steps: - Introduction of said aqueous solution of reuterin obtained from fermentation into a reactor operating under a pressure higher than atmospheric pressure, said solution having a reuterin content by weight of between 0.1% and 10%; - 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. A method according to claim 1, wherein the aqueous solution of reuterin from fermentation introduced into the reactor operating under pressure greater than atmospheric pressure has a reuterin content by weight of between 1.5% and 5%.

3. Process according to claim 1 or 2, in which the aqueous solution of reuterin resulting from a fermentation introduced into the reactor operating under pressure higher than atmospheric pressure has a pH between 3 and 12, preferably between 4 and 7.

4. A method according to any preceding claim, wherein the pressure reactor operates in a pressure range of 0.1 MPa to 2 MPa, preferably between 0.15 MPa and 1.7 MPa.

5. A method according to any one of the preceding claims, wherein the pressure reactor operates with a residence time between 0.2 h and 3 h, preferably between 0.5 h and 1 h.

6. Method according to any one of the preceding claims, comprising a prior step of separating the suspended matter contained in the aqueous solution of reuterin resulting from fermentation upstream of the pressure reactor.

7. Method according to claim 6, comprising a step of recovering the suspended materials after separation by combustion, gasification or spreading.

8. 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 low in reuterin and acrolein obtained at the outlet of the pressurized reactor.

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

10. A method according to any preceding claim, wherein the various steps are each carried out in batch, semi-batch, continuous or semi-continuous mode.

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

12. Use of acrolein according to claim 11 for the manufacture of methionine and its derivatives.

13. Use of acrolein according to claim 11 for the manufacture of glutaraldehyde and its derivatives.

14. Use of acrolein according to claim 11 for the manufacture of acrylic acid and its derivatives.

15. Method according to any one of claims 1 to 10, in which the reuterin contained in the aqueous solution of reuterin resulting from a fermentation introduced into the reactor operating under higher pressure has a biosourced carbon content, measured according to the standards ASTM D6866 or EN 16640, greater than or equal to 5%.

16. Acrolein obtained according to the process of claim 15 having a biosourced carbon content, measured according to the ASTM D6866 or EN 16640 standards, greater than or equal to 5%.

17. Use of acrolein according to claim 16 for the manufacture of methionine and its derivatives.

18. Use of acrolein according to claim 16 for the manufacture of glutaraldehyde and its derivatives.

19. Use of acrolein according to claim 16 for the manufacture of acrylic acid and its derivatives.

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