Process for producing an alcohol by reductive hydroformylation in the presence of porous catalytic capsules

Abstract

A reductive hydroformylation process by reaction between at least one alkene and a gaseous mixture comprising at least carbon monoxide and dihydrogen in the presence of porous catalytic capsules dispersed in at least one organic liquid phase L1. Said porous catalytic capsules, formed from a Pickering emulsion, consist of a liquid core comprising at least one liquid phase L2 comprising at least said reductive hydroformylation catalyst and a porous crust formed by solid particles crosslinked by a crosslinking agent.

Description

Title of the invention: Process for producing an alcohol by reductive hydroformylation in the presence of porous catalytic capsules technical field

[0001] The present invention relates to the field of manufacturing alcohols, major reaction intermediates for the manufacture in particular of esters, acids, amines in the field of solvents, detergents and plasticizers from an alkene and a gaseous mixture comprising carbon monoxide and dihydrogen in the presence of a catalyst in the form of porous catalytic capsules. State of the art

[0002] Hydroformylation is one of the largest catalyzed processes in a homogeneous. This process allows the synthesis of aldehydes from olefins. However, very often, these aldehydes are not the desired products but rather their reduction to alcohols. Therefore, most processes operate in two steps: a first hydroformylation step and a second hydrogenation step. To improve implementation, it is possible to transform an aldehyde into an alcohol via a reductive hydroformylation process. The use of synthesis gas is more advantageous in such a catalytic system, which eliminates the risks associated with using pure hydrogen for the hydrogenation of the aldehyde in a two-step reaction.

[0003] A large-scale industrial application of reductive hydroformylation is the Shell process using a cobalt catalyst modified with tributylphosphine (US3239569A, US3239570A). In this process, the use of the [Co2(CO)6(PBu3)2] complex under reductive hydroformylation conditions on pent-l-ene at 150°C and 35 bar (H2 / CO = 1) gives a 50% conversion with an aldehyde / alcohol ratio of 30 / 70, whereas [Co2(CO)8] under the same conditions gives 95 / 5 (Journal of Organometallic Chemistry, 1968, 13, 469-477). The alcohols formed are separated by distillation, which can lead to the degradation of a portion of the complex that is not separated upstream of this distillation step.

[0004] Kaneda and Teranishi studied the reductive hydroformylation reaction under carbon monoxide and dihydrogen with rhodium catalysts in the presence of amines as ligands such as N,N,N',N'-tetramethyl-1,3-propanediamine (TMPDA). With octene-1, they mainly formed n-nonanol with an isomerized olefinic substrate (Chemistry Letters, 1981, 12, 1763-1766). However, in this implementation, the rhodium cannot be easily separated for recycling.

[0005] To facilitate catalyst recycling, Gorbunov et al. implemented a biphasic alkane / triethanolamine (TEOA) system. TEOA acts as both a ligand and a solvent. A reductive hydroformylation test was performed on octene-1 with this catalytic system under 6 MPa of carbon monoxide and dihydrogen (1:1) at 100°C. After 18 h, the total nonanol yield was 91%, with no nonanal in the mixture but some residual isoaldehydes and internal octenes (Molecular Catalysis, 2021, 516, 112010). Vorholt's team used dimethylaminoethanol (DMAE) in water with a water / amine ratio of 1.5 and olefins from C5 to C10. Their catalytic system is capable of converting olefins of different chain lengths into alcohols in a single conversion step (Catalysis Science Technology, 2022, 12, 728-736).Monflier's team also reports the catalysis of the reductive hydroformylation of methyl 10-undecenoate in a liquid / liquid biphasic system. The rhodium / amine catalytic system is immobilized in an ionic liquid phase, while the olefin and products are in a nonpolar layer. Under optimized conditions, the potassium N,N-dimethyltaurinate salt associated with rhodium, immobilized in l-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, achieved a 93% alcohol yield. With only 2 amine equivalents relative to rhodium, the catalytic system is efficiently immobilized in the ionic liquid for recycling (ACS Sustainable Chemistry Engineering, 2022, 10, 11310-11319). However, these implementations in a two-phase environment are limited by the small exchange surfaces between the two liquid phases. Object of the invention

[0006] The applicant has developed a process for manufacturing alcohols by reacting an alkene with a gaseous mixture of carbon monoxide and dihydrogen in the presence of porous liquid-core capsules containing a catalyst for alcohol synthesis. The alkene, contained in an organic liquid phase called the continuous phase, reacts with the carbon monoxide and dihydrogen in the liquid core of the capsules, which consists of a liquid phase comprising a compound of a transition metal selected from groups 8, 9, and 10 of the periodic table of elements. The alcohols formed by the reaction are extracted from the continuous phase.

[0007] The present invention therefore offers the advantage of facilitating the separation of the continuous phase from the encapsulated metal compounds. This advantage is particularly important in the context of shortages of certain critical metals, such as cobalt, and due to the high cost of certain metals, such as rhodium.

[0008] The liquid-core capsules containing the metal compound are prepared from a Pickering emulsion which has the advantage of being able to adjust the size of the Capsules are prepared using techniques well-known to those skilled in the art, such as filtration, which is not suitable for very small capsules. This method of preparing liquid-core capsules also has the advantage of using a sol-gel process, which allows control over the properties of the porous capsule shell (thickness and porosity) to suit the implementation of the process, particularly to optimize the transfer of reagents and products through the porous shell.

[0009] The present invention also has the advantage of developing a large exchange surface area between the liquid phase containing the alkene to be reacted and the liquid phase containing the catalyst, without the use of surfactants that do not allow the separation of the catalyst and that can have an environmental impact. This large exchange surface area between the two liquid phases strongly promotes the reaction, even with olefins that are only slightly soluble in the aqueous phase, such as olefins with a long carbon chain whose water solubility is less than 100 mg / L. Furthermore, the liquid-core capsules have the advantage of acting as microreactors, thus promoting the reaction kinetics.

[0010] The use of liquid-core capsules according to the invention also eliminates the need for vigorous agitation, which is traditionally required to transfer a molecule between two liquid phases, thus reducing the energy demand of the process. They allow for an emulsion that remains stable after its formation; it is no longer necessary to supply energy to maintain the two liquid phases in contact.

[0011] Finally, the process according to the present invention has the advantage of being able to be implemented continuously with continuous addition of alkene to the continuous phase and / or continuous withdrawal of the continuous phase to separate the reaction products. Such continuous implementation allows for productivity gains.

[0012] The present invention therefore has the advantage of implementing a process for manufacturing alcohols from reagents that are very poorly soluble in water and of being able to easily recover the catalyst.

[0013] The present invention relates to a process for producing an alcohol by reductive hydroformylation between at least one alkene and a gaseous mixture comprising at least carbon monoxide and dihydrogen in the presence of a catalyst comprising at least the following steps:

[0014] 1) porous catalytic capsules dispersed in at least one phase are prepared organic L1 according to the following steps:

[0015] a. A mixture comprising at least one liquid phase L2, immiscible in the organic phase L1, is emulsified, comprising at least one reductive hydroformylation catalyst based on metal compounds selected from the groups 8, 9 and 10 according to the periodic classification of elements, an organic phase L1 and solid particles to form a Pickering emulsion comprising droplets of said liquid phase L2 stabilized by the solid particles in the organic phase L1;

[0016] 1b. an agent is added to the Pickering emulsion obtained in step a) crosslinking to form porous catalytic capsules suspended in the organic phase L1; said porous catalytic capsules comprising a liquid core comprising at least said liquid phase L2 comprising at least said reductive hydroformylation catalyst and a porous shell formed by the crosslinked solid particles;

[0017] 2) The reductive hydroformylation reaction is carried out by adding at least one alkene and a gaseous mixture comprising at least carbon monoxide and dihydrogen in the organic phase Ll comprising at least said porous catalytic capsules to form at least one alcohol;

[0018] 3) said alcohol formed in step (2) is recovered in said organic phase LL

[0019] Advantageously, said alkene is a C2 Cl8 alkene.

[0020] Preferably, said alkene is a C4 Cl8 alkene.

[0021] Advantageously, the metal compounds are chosen from cobalt or rhodium compounds.

[0022] Advantageously, said liquid phase L2 comprises at least water.

[0023] Preferably, said liquid phase L2 comprises at least water with added acid or base.

[0024] Advantageously, said liquid phase L2 comprises at least one ionic liquid.

[0025] Advantageously, porous catalytic capsules have an average diameter in numbers ranging from 1 pm to 1000 pm.

[0026] Advantageously, the solid particles added in step a) are silica particles.

[0027] Advantageously, the crosslinking agent added in step 1b) is chosen from at least one silica precursor compound of the silicate or orthosilicate or silicic or orthosilicic or alkoxysilane type.

[0028] Advantageously, the mass ratio between the crosslinking agent and the solid particles is between 1 and 10.

[0029] Advantageously, the organic phase Ll comprises at least one or more saturated hydrocarbons selected from linear or cyclic alkanes, and / or one or more unsaturated hydrocarbons selected from olefins or aromatic compounds, alcohols and aldehydes.

[0030] Advantageously, the organic phase Ll comprises at least one or more organic compounds comprising between 3 and 20 carbon atoms.

[0031] Advantageously, the organic phase L1 is constituted by said alkene.

[0032] Advantageously, the volume ratio between the liquid phase L2 and the organic liquid phase L1 is between 2:1 and 1:10. Detailed description of the invention

[0033] 1. Definitions

[0034] Emulsion:

[0035] An emulsion is a heterogeneous medium formed by the dispersion of one liquid (dispersed phase) in another liquid (continuous phase). Emulsions are generally stabilized by surfactants due to their amphiphilic properties.

[0036] Pickering emulsion:

[0037] Emulsions can also be stabilized with particles; this is called a Pickering emulsion.

[0038] Pickering emulsions are indeed liquid / liquid dispersions stabilized by nanoparticles or aggregates of solid nanoparticles that accumulate at the interface between the two immiscible liquids (generally water and oil) and prevent the coalescence of the dispersed droplets (see, for example, Pickering, SU (1907). J. Chem. Soc. Trans. 91, 2001-2021). In fact, the particles used to make Pickering emulsions are capable of irreversibly adsorbing at the interface between the two liquids, resulting in much more effective emulsion stabilization than the adsorption of surfactants (see, for example, Aveyard, R., Binks, BP, and Clint, JH (2003); Adv. Colloid Interface Sci. 100, 503-546). The direction of the emulsion (water in oil or oil in water) is determined by the preferential wettability of the particles towards one or the other phase.In fact, the liquid with the highest wetting power towards the particles will constitute the continuous phase of the emulsion, and the one with the lowest wetting power will constitute the dispersed phase (see, for example, the publication Binks, B., and Lumsdon, S. (2000). Langmuir 16, 8622-8631).

[0039] Pickering emulsions have the advantage of promoting the transfer of mass between the two liquid phases. Indeed, to ensure the transfer of a molecule between two liquid phases, it is necessary to create a large exchange surface between the two liquids.

[0040] Liquid-filled capsules:

[0041] Pickering emulsions can also be strengthened, for example against a pressure drop, by encapsulating the emulsion. These are then referred to as liquid-core capsules.

[0042] This consolidation is achieved through encapsulation of the Pickering emulsion. However, unlike conventional encapsulations, where the envelope is airtight and the encapsulated substance is only released under certain conditions (phenomenon called controlled release), here the envelope is porous in order to facilitate mass transfers between the continuous phase and the dispersed phase.

[0043] This can be done via the sol-gel process. An alkoxysilane (generally TEOS) solubilized in the continuous phase and water from the dispersed phase react at the interface of the emulsion droplets to form a silica shell. These capsules constitute porous inorganic microreactors that allow for continuous reactions, improved pressure resistance, and easier catalyst recovery. The reactants are introduced into the continuous phase and pass through the porous wall to come into contact with the catalyst. The products formed, being chosen for their lower soluble content in the dispersed phase, pass through the wall to migrate into the continuous phase. Thanks to the continuous extraction of products from the dispersed phase where the reaction takes place, an increase in activity and selectivity can be observed.

[0044] An “emulsifier” is a compound or substance that acts as a stabilizer for emulsions, preventing liquids from separating.

[0045] A "hydrophobic" molecule or part of a molecule is a molecule that is repelled by a mass of water and other polar substances.

[0046] A "hydrophilic" molecule or part of a molecule is a molecule that tends to interact with or be dissolved by water and other polar substances.

[0047] “Amphiphile” is a term describing a chemical compound comprising both hydrophilic and hydrophobic properties.

[0048] Particle and droplet sizes:

[0049] Particle size: The solid particles according to the invention can be of various shapes and sizes, for example from a few nanometers to a few microns, or even tens of microns, in the form of substantially spherical or non-spherical beads (FB de Carvalho-Guimarâes, K Leal Correa, T Pereira de Souza, JR Rodriguez Amado, RM Ribeiro-Costa and JO Carréra Silva-Junior (2022) A Review of Pickering Emulsions: Perspectives and Applications, Pharmaceuticals, 15, 1413. https: / / doi.org / 10.3390 / phl5111413). The shape can be substantially spherical, or in the form of a rod, ellipsoid, needle, spindle, nanofibril, nanocage, plate, nanotube, nanocube, etc. (Li W, Jiao B, Li S, Faisal S, Shi A, Fu W, Chen Y and Wang Q (2022) Recent Advances on Pickering Emulsions Stabilized by Diverse Edible Particles: Stability Mechanism and Applications. Front. Nutr. 9:864943. doi: 10.3389 / fnut.2022.864943).The size can vary enormously, from a few nanometers to a few tens of microns. The size obviously depends on the morphology of the particles involved. It is generally determined by scanning and transmission electron microscopy analyses. It is easy to define for spherical particles (diameter), and more difficult for particles whose shape deviates from sphericity. (plates, rods, ellipsoids, needles, etc.), two characteristic sizes are generally specified: the smallest and the longest. Another difficulty arises from the spontaneous formation of aggregates between the elementary particles. A distinction is then made between the size of the elementary particles and the size of the aggregates. For example, commercial silica Aerosil R972 is a mixture of elementary particles between 5 nm and 50 nm with aggregates of average size on the order of 250 nm.

[0050] Droplet size: Droplet size means the largest dimension of the droplets measured by optical microscopy (in particular by Olympus BX51 with analysIS software for image analysis).

[0051] Characterization of the porous structure of the envelope:

[0052] The porous structure of the envelope can be analyzed by nitrogen porosimetry (Micromeritics ASAP 2420) to determine, in particular, the BET surface area and the pore volume. The size distribution of the mesopores can be obtained by applying the B JH method in the case of a type IV isotherm.

[0053] Characterization of crust thickness:

[0054] The thickness of the crust can be obtained by observation in scanning electron microscopy and image analysis of the images obtained (SEM, ZEISS Supra 40 device). 1. Detailed description

[0055] The present invention relates to a process for producing an alcohol by reductive hydroformylation between at least one alkene and a gaseous mixture comprising at least carbon monoxide and dihydrogen in the presence of a catalyst comprising at least the following steps:

[0056] 1) porous catalytic capsules dispersed in at least one phase are prepared organic L1 according to the following steps:

[0057] a. a mixture comprising at least one liquid phase L2, immiscible in the organic phase L1, comprising at least one reductive hydroformylation catalyst based on metal compounds selected from groups 8, 9 and 10 according to the periodic table of elements, an organic phase L1 and solid particles is emulsified in order to form a Pickering emulsion comprising droplets of said liquid phase L2 stabilized by the solid particles in the organic phase L1;

[0058] 1b. an agent is added to the Pickering emulsion obtained in step a) crosslinking to form porous catalytic capsules suspended in the organic phase L1; said porous catalytic capsules comprising a liquid core comprising at least said liquid phase L2 comprising at least said reductive hydroformylation catalyst and a porous envelope formed by cross-linked solid particles;

[0059] 2) The reductive hydroformylation reaction is carried out by adding at least one alkene and a gaseous mixture comprising at least carbon monoxide and dihydrogen in the organic phase L1 comprising at least said porous catalytic capsules to form at least one alcohol;

[0060] 3) said alcohol formed in step (2) is recovered in said organic phase Ll.

[0061] Step 1) porous catalytic capsules dispersed in a phase are prepared organic Ll.

[0062] The porous catalytic capsules are prepared by going through an intermediate step of forming a so-called Pickering emulsion (step 1a). Instead of using the droplets of solution L2 containing the catalyst surrounded by solid particles as is, the invention creates an envelope from these solid particles arranged around the droplets. Thus encapsulated, the droplets are more stable, easier to recycle and implement, and can also withstand higher pressure. The porous catalytic capsules formed from a Pickering emulsion therefore make it possible to confine the hydroformylation catalyst within the liquid core (so-called dispersed phase). The porous envelope of the capsules will serve for the exchange of reactants and products.These capsules, formed from a Pickering emulsion, present a large contact surface between the alkene and the capsules containing the hydroformylation catalyst, and allow the use of alkenes that are poorly soluble in water.

[0063] The manufacture of porous catalytic capsules comprises at least the following steps:

[0064] a. a mixture is emulsified comprising at least one liquid phase L2 immiscible in the organic phase L1 comprising at least one reductive hydroformylation catalyst based on metal compounds selected from groups 8, 9 and 10 according to the periodic table of elements, an organic phase L1 and solid particles in order to form a Pickering emulsion comprising droplets of said liquid phase L2 stabilized by the solid particles in the organic phase L1;

[0065] 1b. an agent is added to the Pickering emulsion obtained in step a) crosslinking to form porous catalytic capsules suspended in the organic phase L1; said porous catalytic capsules comprising at least a liquid core comprising at least said liquid phase L2 comprising at least said reductive hydroformylation catalyst and a porous shell formed by said crosslinked solid particles;

[0066] Step a) preparation of the Pickering emulsion.

[0067] In the present invention, an immiscible liquid phase L2 is brought into contact with an organic phase L1 comprising at least one reductive hydroformylation catalyst based on metal compounds selected from groups 8, 9, and 10 according to the periodic table of elements, an organic phase L1, and solid particles. When all these species are brought into contact, a biphasic mixture comprising an organic phase L1 and a liquid phase L2 is formed. The biphasic mixture is emulsified to form a Pickering emulsion L2 in L1, i.e., droplets of L2, comprising said reductive hydroformylation catalyst, stabilized by the solid particles in the organic phase L1.

[0068] Liquid phase L2 immiscible in L1

[0069] The liquid phase L2 is a solvent that is not miscible in the organic phase L1 and comprises at least one reductive hydroformylation catalyst based on compounds of metals from groups 8, 9 and 10 according to the periodic table of elements.

[0070] Advantageously, this solvent is selected from fluorinated solvents, ionic liquids, amines, or water. These solvents can be used alone or in mixtures. Advantageously, this solvent contains an ionic liquid, an amine, and / or water. Preferably, the solvent contains an ionic liquid.

[0071] In an embodiment where the chosen solvent is water, the liquid phase L2, which is immiscible in the organic phase L1 constituting the dispersed phase, comprises at least water in which is dissolved at least one transition metal compound chosen from groups 8, 9, and 10. Advantageously, the aqueous phase may be water with the addition of an organic acid or base (e.g., tetraethylammonium hydroxide (TEAOH), triethylamine, acetic acid, formic acid, etc.) or an inorganic acid or base (ammonia, sodium hydroxide, nitric acid, hydrochloric acid, etc.) in order to vary the pH of this aqueous phase. Advantageously, the pH is between 6 and 11, and preferably between 6 and 9.

[0072] In another embodiment where the chosen solvent is an ionic liquid, the liquid phase L2 which constitutes the dispersed phase comprises at least one ionic liquid in which is dissolved at least one compound of a transition metal from groups 8, 9 and 10 according to the periodic table of elements.

[0073] An ionic liquid medium comprises at least one organic cation Q+ and one anion A.

[0074] Advantageously, the organic cation Q+ is a quaternary ammonium and / or a quaternary phosphonium and / or a trialkylsulfonium, and the anion A is an anion forming with the cation Q+ a liquid salt below 150°C.

[0075] Advantageously, Fanion A is selected from the tetrafluoroborate, tetraalkylborate, hexafluorophosphate, hexafluoroantimonate, alkylsulfonate, particularly methylsulfonate, and perfluoroalkylsulfonate anions, particularly the trifluoromethylsulfonate, fluorosulfonate, sulfate, phosphate, perfluoroacetate, in particular trifluoroacetate, perfluorosulfonamide, in particular bis-trifluoromethanesulfonyl (CF3SO2)2N amide, perfluorosulfomethide, in particular tris-trifluoromethanesulfonyl (CF3SO2)3C methylide, and carboranes.

[0076] Preferably, Fanion A is an anion that forms a liquid salt with the Q+ cation below 150°C and advantageously below 90°C, and preferably at most 50°C.

[0077]

[0078] Advantageously, the Q+ cation is chosen from the following compounds: [Chem.l]

[0079] for which R1, R2, R3, R4, R5 and R6 are identical or different, linked or not to each other, represent hydrogen or hydrocarbyl groups having from 1 to 12 carbon atoms, in particular alkyl groups, saturated or unsaturated, cycloalkyl or aromatic, aryl or aralkyl, comprising from 1 to 12 carbon atoms.

[0080] By way of examples of Q+A ionic liquids according to the invention, we may mention N-butylpyridinium hexafluorophosphate, N-ethylpyridinium tetrafluoroborate, butyl-3-methyl-1-imidazolium hexafluoroantimonate, butyl-3-methyl-1-imidazolium hexafluorophosphate, butyl-3-methyl-1-imidazolium trifluoromethylsulfonate, pyridinium fluorosulfonate, trimethylphenylammonium hexafluorophosphate, bis-trifluoromethylsulfonylamide of butyl-3-methyl-1-imidazolium, bis-trifluoromethylsulfonylamide of triethylsulfonium, bis-trifluoromethylsulfonylamide of tributylhexylamnium, butyl-3-methyl-1-imidazolium trifluoroacetate, bis-trifluoromethylsulfonylamide of butyl-3-dimethyl-1,2-imidazolium. These salts can be used alone or in mixtures.

[0081] According to a particular embodiment of the invention, the ionic liquid is mixed with water.

[0082] In another embodiment where the chosen solvent is a fluorinated solvent, the liquid phase L2 which constitutes the dispersed phase comprises at least one fluorinated solvent in which is dissolved at least one compound of a transition metal from groups 8, 9 and 10.

[0083] The fluorinated solvent used comprises at least one or more partially or totally fluorinated linear, cyclic, or branched hydrocarbons that may bear heteroatoms and functional groups such as ethers, tertiary amines, carboxylic acids, phosphonic acids, and sulfonic acids. Preferably, the solvent is perfluorinated. The fluorinated hydrocarbon(s) preferably have between 3 and 20 carbon atoms, and more preferably between 5 and 16 carbon atoms. Non-limiting examples include perfluoro(methylcyclohexane), perfluorooctanoic acid, and perfluorooctanesulfonic acid. These solvents may be used alone or in mixtures.

[0084] According to a particular embodiment of the invention, the fluorinated solvent is mixed with water.

[0085] In another embodiment where the chosen solvent is an amine solvent, the phase liquid L2 which constitutes the dispersed phase comprises at least one amine solvent in which is dissolved at least one compound of a transition metal from groups 8, 9 and 10.

[0086] The amine solvent used includes primary, secondary and tertiary amines. Preferably the solvent is a tertiary amine. The amine solvent has the formula NR1R2R3 in which the radicals RI, R2 and R3 are identical or different and are chosen from a hydrogen atom, an alkyl or aralkyl group having from 1 to 20 carbon atoms (in C1-C20) cyclic or non-cyclic, containing or not a heteroatom, bearing or not functional groups such as alcohols, amines, ethers, carboxylic acids, phosphonic acids and sulfonic acids.Advantageously, RI, R2, and R3 are chosen from an alkyl group having 1 to 10 carbon atoms (Cl-ClO) containing or not a heteroatom, bearing or not functional groups; a cycloalkyl group having 3 to 10 carbon atoms (C3-C10) containing or not a heteroatom, bearing or not functional groups; and a substituted or unsubstituted aryl group having 4 to 15 carbon atoms (C4-C15) containing or not a heteroatom, bearing or not functional groups. Non-limiting examples include triethanolamine, 2-(dimethylamino)ethanol, 3-(dimethylamino)-1,2-propanediol, and N,N,N',N'-tetramethyl-1,3-propanediamine. These solvents can be used alone or in mixtures.

[0087] According to a particular embodiment of the invention, the amine solvent is mixed with water.

[0088] The transition metal compounds usable according to the invention are generally all transition metal compounds from groups 8, 9, and 10 according to the periodic table of elements, and in particular those known to those skilled in the art for hydroformyling olefins. A metal compound is understood to be a metal salt. or a metallic complex associated or not with at least one ligand. The metal is preferably chosen from cobalt, rhodium, iridium, ruthenium, palladium and platinum, and advantageously from cobalt or rhodium. The metal compound is preferably chosen from HRh(CO)(PR3)3, HRh(CO)2(PR3), HRh(CO)[P(OR)3 ]3, Rh(acac)(CO)2, (acac meaning acetylacetonate), Rh6(CO)i6, [Rh(norbomadiene) (PPh3)2]+[PF6], [Rh(CO)3(PPh3)2]+[BPh4], RhCl(CO)(PEt3)2, [RhCl(cyclooctadiene)]2 , [Rh(CO)3(PR3)2]+[BPh4], [Rh(CO)3(PR3)2]+[PF6], HCo(CO)4, Ru3(CO)12, [RuH(CO) (acetonitrile)2(PPh3)3]+[BF4], PtCl2(cyclooctadiene), [lr(CO)3(PPh3)]+[PF6], [HPt(PEt3 )3]+[PF6], Rh2O3, Pd(NO3)2 and Rh(NO3)3. R is chosen from an atom, an alkyl or aralkyl group having from 1 to 15 carbon atoms (in Cl-Cl 5) cyclic or not, containing or not a heteroelement.Advantageously, R is chosen from an alkyl group having between 1 and 10 carbon atoms (in Cl-CIO) containing or not a heteroelement, a cycloalkyl group having from 3 to 10 carbon atoms (in C3-C10) containing or not a heteroelement, and a substituted or unsubstituted aryl group having from 4 to 15 carbon atoms (in C4-C15) containing or not a heteroelement.

[0089] Preferably, the metal compound comprises organic ligands bearing a phosphorus atom (phosphorus ligand), a nitrogen atom (nitrogen ligand), an arsenic atom (e.g., arsines), or an antimony atom (e.g., stibines). They may be mono- or bidentate. These ligands may also bear at least one other functional group, such as an amine, ammonium, alcohol, carboxylic acid, or sulfonate, on the heteroatom and / or the carbon chain. Examples include the sodium salt of triphenylphosphine monosulfonate, the sodium salt of triphenylphosphine trisulfonate, potassium A,A-dimethyltaurinate salt, 1-Butyl-3-methylimidazolium A,A-dimethyltaurinate salt, and triethanolamine.

[0090] The concentration of the metal compound, expressed in metal atoms, in the dispersed phase is advantageously between 0.1 mmole per liter of phase L2 and 500 mmoles per liter, preferably between 1 and 200 mmoles per liter, and even between 1 and 100 mmoles per liter, or even 1 to 50 mmoles per liter.

[0091] According to one embodiment of the invention, the metal compound comprises a ligand whose quantity is chosen so that the molar ratio of the quantity of ligand divided by the quantity of metal is between 1 and 1000, and preferably between 1 and 100, and even 1 and 20.

[0092] Organic phase L1

[0093] The organic phase L1 can be any liquid immiscible with phase L2. A person skilled in the art may preferentially choose an organic compound or a mixture of organic compounds with a high partition coefficient for the alcohol formed.

[0094] In one or more particular embodiments of the invention, the organic phase L1 comprises at least one or more saturated hydrocarbons selected from linear or cyclic alkanes, and / or one or more unsaturated hydrocarbons selected from olefins or aromatic compounds, alcohols and aldehydes.

[0095] Advantageously, said organic compound or compounds comprise between 3 and 20 carbon atoms, preferably between 5 and 16 carbon atoms.

[0096] Without being exhaustive, the organic phase L1 comprises one or more organic compounds selected from pentane, hexane, heptane, octane, decane, dodecane, hexadecane, cyclohexane, methylcyclohexane, toluene, paraxylene, metaxylene, orthoxylene, ethylbenzene.

[0097] In one or more particular embodiments of the invention, the organic phase L1 is composed of one of the alkene-type reactants of the hydroformylation reaction.

[0098] In one or more particular embodiments of the invention, the organic phase L1 is composed of one of the alcohol-type products of the reductive hydroformylation reaction.

[0099] In one or more particular embodiments of the invention, the organic compounds of phase L1 are chosen to facilitate their separation from the product of the reductive hydroformylation reaction. In a particular embodiment of the invention, they have a boiling point far removed from that of the product of the reductive hydroformylation reaction.

[0100] The volume ratio between the liquid phase L2 and the organic phase L1 is preferably between 2:1 and 1:10, in particular between 1:1 and 1:5.

[0101] Solid particles

[0102] The solid particles according to the invention can be of various shapes and sizes, for example from a few nanometers to a few microns, or even tens of microns, in the form of substantially spherical or non-spherical beads (FB de Carvalho-Guimarães, K Leal Correa, T Pereira de Souza, JR Rodriguez Amado, RM Ribeiro-Costa and JO Carréra Silva-Junior (2022) A Review of Pickering Emulsions: Perspectives and Applications, Pharmaceuticals, 15, 1413. https: / / doi.org / 10.3390 / phl5111413). The shape can be substantially spherical, or in the form of a rod, ellipsoid, needle, spindle, nanofibril, nanocage, plate, nanotube, nanocube, etc. (Li W, Jiao B, Li S, Faisal S, Shi A, Fu W, Chen Y and Wang Q (2022) Recent Advances on Pickering Emulsions Stabilized by Diverse Edible Particles: Stability Mechanism and Applications. Front. Nutr. 9:864943. doi: 10.3389 / fnut.2022.864943).

[0103] Advantageously, they are modified to change their surface properties (in particular to modify their wettability). They can be of a single type, or can be used in mixtures of several types of particles (in terms of size, shape and wettability).

[0104] Optionally, at least one surfactant is added to the particles. This surfactant (or each of them if a mixture of surfactants is used) can be anionic, cationic, nonionic, or amphoteric.

[0105] Advantageously, the solid particles are selected from: metal hydroxide or oxide particles such as AlOOH, Al2O3, TiO2, Fe3O4, Ce2O3 or SiO2, preferably at least partially functionalized with hydrophobic hydrocarbon groups; clay particles, preferably at least partially modified with organic or amphiphilic molecules; organic particles such as carbon nanotubes, graphene oxide particles, synthetic polymer particles such as polyethylene glycol (PEG), polystyrene (PS), polylactic acid (PLA), polycaprolactone (PCL), or latex particles; particles of a material of natural origin, preferably selected from hydroxyapatite, chitosan, cyclodextrin, dextran, particles in the form of cellulose nanocrystals or nanofibers; particles of biological material, particularly food-grade, preferably selected from starch,Zein, soy protein, bacteria and yeasts.

[0106] These particles are advantageously silica particles having an affinity for each of the two phases. Given the hydrophobic nature of the organic liquid phase, the silica particles, which are naturally hydrophilic due to the presence of silanol groups, are preferentially functionalized with hydrophobic hydrocarbon groups.

[0107] In a particular embodiment of the invention, the solid particles are nanometric, with an average size between 1 nm and 500 nm, preferably between 5 nm and 300 nm.

[0108] Advantageously, the solid particle content is between 0.1% by weight and 10% by weight, in particular between 0.5% by weight and 5% by weight, and preferably between 0.5% by weight and 3% by weight of solid particles relative to the weight of the mixture obtained at the end of step 1a).

[0109] Emulsification

[0110] Emulsification transforms the biphasic mixture into dispersed droplets of phase L2 within the organic phase L1, forming a Pickering emulsion. Advantageously, the largest dimension of the droplets is between 1 pm and 1000 pm, preferably between 1 pm and 140 pm, preferably between 2 pm and 100 pm, and even more preferably between 10 pm and 50 pm. The droplet size is measured by optical microscopy (in particular, using an Olympus BX51 with analysIS software for image analysis).

[0111] Emulsification is carried out by any type of system that supplies energy to generate the emulsion known to those skilled in the art. While not exhaustive, examples include rotor-stator type tools, propeller agitators, static mixers, colloid mills, membrane systems, ultrasonic stirring, and microfluidic systems. The principle of these mixers is described, for example, in the Techniques de l'Ingénieur dossier J2153V1: Emulsification Processes - Equipment Techniques, by M. Poux and JP Canselier, June 10, 2004. A microfluidic system is described, for example, in the Techniques de l'Ingénieur dossier J8010V1: Microfluidics and Formulation - Emulsions and Complex Colloidal Systems, by V. Nardello-Rataj and JF Ontiveros, May 10, 2019.

[0112] In a particular embodiment of the invention, emulsification is carried out using a rotor-stator system of the type of the system marketed under the name Ultra-Turrax.

[0113] Advantageously, the ratio between the largest dimension of the dispersed droplets and the largest dimension of the amphiphilic solid particles is preferably at least 100. (The largest dimension is understood to be the diameter when the particles are substantially spherical). They are located at the interface of the water / oil emulsion droplets.

[0114] The solid particles are at the interface between the two phases.

[0115] Step 1b) Crosslinking of the porous capsule envelope

[0116] A crosslinking agent is added to the Pickering emulsion obtained in step a) in order to form porous catalytic capsules in suspension in the organic phase L1; said porous catalytic capsules comprising a liquid core comprising at least said liquid phase L2 comprising at least said hydroformylation catalyst and a porous shell formed by the crosslinked solid particles;

[0117] The solid material of the capsule shell is formed by said particles which stabilize the Pickering emulsion (step 1a) and which are crosslinked by the addition of a crosslinking agent. This crosslinking agent allows the solid particles to bind together.

[0118] The porous envelope consists of two elements:

[0119] - on the one hand, the solid particles used in the preparation of the emulsion of Pickering. The solid particles are described above in the description of the Pickering emulsion.

[0120] - on the other hand, a so-called crosslinking agent, which forms a porous envelope allowing the particles to bind together.

[0121] Crosslinking agent:

[0122] Advantageously, the crosslinking agent is chosen from at least one silica precursor compound of the silicate, orthosilicate, silicic, or orthosilicic type. or alkoxysilane, in particular selected from at least tetramethyl orthosilicate, tetraethyl orthosilicate, tetrabutyl orthosilicate, trimethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane and triethoxysilane. This type of crosslinking agent is indeed capable of crosslinking by hydrolysis, and thus serves as a base material for forming a solid shell.

[0123] Advantageously, the capsule shell is manufactured by hydrolysis of the precursor at a temperature between 20°C and 60°C, for a heating time of between 2 h and 24 h. Initially, the alkoxysilane hydrolyzes, releasing the corresponding alcohol. Then, in a second step, the hydrolyzed alkoxysilane condenses, releasing water to form a Si-O-Si bond. (Zhang, X.; Hou, Y.; Ettelaie, R.; Guan, R.; Zhang, M.; Zhang, Y.; Yang, H. J. Am. Chem. Soc. 2019, 141 (13), 5220-5230).

[0124] Advantageously, the mass ratio between the crosslinking agent and the solid particles is between 1 and 10, in particular between 1 and 6.

[0125] The crosslinking agent can be introduced into the aqueous dispersed phase before the formation of the Pickering emulsion or be introduced a posteriori into the continuous phase.

[0126] An organic base or acid (e.g., tetraethylammonium hydroxide (TEAOH), triethylamine, acetic acid, formic acid, etc.) or an inorganic base or acid (ammonia, sodium hydroxide, nitric acid, hydrochloric acid, etc.) may be added to the aqueous dispersed phase to modify its pH in order to promote crosslinking and / or alter the porous architecture of the capsules. In this case, the acid or base is introduced at the same time as the catalyst; a pH between 6 and 11 is advantageously targeted, preferably between 6 and 9.

[0127] A person skilled in the art will be able to choose the appropriate reactor for this operation. Generally, crosslinking is carried out in a rotary evaporator-type reactor or a double-jacketed glass reactor equipped with a four-bladed agitator or other type of impeller ensuring the mixing of the reaction medium.

[0128] Advantageously, the liquid-core capsules have an average number diameter of between 1 pm and 1000 pm, preferably between 2 pm and 100 pm, which allows them to be easily separated from the reaction system.

[0129] The preparation process according to the invention may also include a step of washing the capsules in particular with a solvent that is not miscible with the encapsulated catalytic composition, in particular non-aqueous, and preferably based on hydrocarbon(s).

[0130] The average size of the capsules is measured by optical microscopy (Olympus BX51 with analysIS software for image analysis) or by scanning electron microscopy (SEM, ZEISS Supra 40 instrument).

[0131] Said capsules advantageously have a pore volume (measured by nitrogen physisorption at P / PO max) between 0.2 ml / g and 0.8 ml / g and a BET surface (measured by nitrogen physisorption) between 60 m2 / g and 350 m2 / g.

[0132] Step 2) Reductive hydroformylation reaction

[0133] The reductive hydroformylation reaction is carried out by adding at least one alkene and a gaseous mixture comprising at least carbon monoxide and dihydrogen to a mixture comprising the organic phase L1 and said porous catalytic capsules to form at least one alcohol.

[0134] With the embodiment according to the invention, the medium is three-phase gas / liquid / solid. The gaseous phase consists of the gaseous mixture comprising carbon monoxide and dihydrogen. The liquid phase consists of the mixture of the alkene and the organic phase L1, and the solid phase consists of the porous catalytic capsules containing the liquid phase L2.

[0135] A person skilled in the art can use various implementations of this reaction. The process can be implemented in a closed, semi-open, or continuous system, with one or more reaction stages in steel reactors capable of withstanding the pressures and temperatures applied, as well as corrosion. Each reactor is equipped with a device for efficiently removing the heat released by the reaction and regulating the temperature to the desired level. Furthermore, it is useful to ensure good contact between the liquid phase and the syngas by forced circulation of the reaction mixture within the reactor.

[0136] These liquid-core capsules can be brought into contact with the reagent(s), for example in free suspension or in a fixed bed with upstream or downstream co-current in a reactor.

[0137] The reactants (alkene and gaseous mixture) react upon contact with the hydroformylation catalyst contained in the porous capsules and form reaction products which diffuse out of the capsules.

[0138] Alcène:

[0139] Alkenes, or olefins, capable of being hydroformylated (reductively) are selected from the group consisting of monoolefins, diolefins, particularly conjugated diolefins, and olefinic compounds comprising one or more heteroatoms, especially in unsaturated groups such as ketone and carboxylic acid functions. Advantageously, the alkenes according to the invention are C2 to C8 alkenes, preferably C4 to C8, and preferably C5 to C18.

[0140] By way of examples, one can cite the reductive hydroformylation of pentenes to hexanol and methylpentanol, of hexenes to isoheptanols, of isooctenes to isononanols and of C10 to C18 olefinic cuts to Cl1 to C19 alcohols.

[0141] Advantageously, the reductive hydroformylation temperature is between 30 °C and 250 °C, preferably between 30 °C and 150 °C, and preferably between 50 °C and 120 °C.

[0142] Advantageously, the ratio of the partial pressures of dihydrogen and carbon monoxide used in the reaction medium for hydroformylation is between 10:1 and 1:10, preferably between 5:1 and 1:1, and preferably between 2:1 and 1:1, but any other ratio may be used depending on the implementation of the process. The pressure may be between 1 MPa and 35 MPa, advantageously between 1 MPa and 10 MPa.

[0143] The duration of the reaction depends on the operating conditions and the reactivity of the catalyst. It will be adjusted by a person skilled in the art to obtain the desired alcohol yield in a minimum time.

[0144] According to a particular embodiment of the invention, the alkene is continuously introduced into the organic phase LL

[0145] Step 3) Recovery of alcohol in the organic phase L1

[0146] Advantageously, the step of recovering the alcohol formed in the organic phase L1 takes place in two steps:

[0147] -Step 3a) Separation of the porous catalytic capsules from said organic phase LL

[0148] Said organic phase L1 is separated from the porous catalytic capsules by liquid / solid separation techniques known to those skilled in the art such as filtration, decantation, or centrifugation.

[0149] -Step 3b) Separation of the alcohol in the organic phase Ll;

[0150] At the end of the reductive hydroformylation reaction, the organic phase L1 comprises at least the aforementioned organic compounds, the unreacted alkene, the alcohol formed, the products of secondary reactions, and gaseous species solubilized in the liquid. The alcohol is separated by any method known to those skilled in the art, and preferably by distillation (Technique de l'ingénieur, 2016, J5750 V2).

[0151] According to a particular embodiment of the invention, the alcohol is separated from the organic phase Ll as it is formed by distillation from a withdrawal of the phase Ll which is returned to the reactor after partial or total evaporation of the alcohol in this withdrawal.

Claims

Demands

1. A process for producing an alcohol by reductive hydroformylation between at least one alkene and a gaseous mixture comprising at least carbon monoxide and dihydrogen in the presence of a catalyst comprising at least the following steps: 1) porous catalytic capsules dispersed in at least one organic phase L1 are prepared according to the following steps: a. a mixture comprising at least one liquid phase L2, immiscible in the organic phase L1, comprising at least one reductive hydroformylation catalyst based on compounds of metals selected from groups 8, 9 and 10 according to the periodic table of elements, an organic phase L1 and solid particles is emulsified to form a Pickering emulsion comprising droplets of said liquid phase L2 stabilized by the solid particles in the organic phase L1; 1b.1) a crosslinking agent is added to the Pickering emulsion obtained in step 1a) in order to form porous catalytic capsules in suspension in the organic phase L1; said porous catalytic capsules comprising a liquid core comprising at least said liquid phase L2 comprising at least said reductive hydroformylation catalyst and a porous shell formed by the crosslinked solid particles; 2) the reductive hydroformylation reaction is carried out by adding at least one alkene and a gaseous mixture comprising at least carbon monoxide and dihydrogen to the organic phase L1 comprising at least said porous catalytic capsules to form at least one alcohol; 3) said alcohol formed in step (2) is recovered in said organic phase L1.

2. A process according to claim 1, wherein said alkene is a C2 Cl8 alkene.

3. A process according to claim 1, wherein said alkene is a C4 to Cl8 alkene.

4. A method according to any one of the preceding claims, wherein the metal compounds are selected from cobalt or rhodium compounds.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15. A method according to any one of the preceding claims, wherein said liquid phase L2 comprises at least water. A process according to any one of the preceding claims, wherein said liquid phase L2 comprises at least water with added acid or base. A method according to any one of the preceding claims, wherein said liquid phase L2 comprises at least one ionic liquid. A method according to any one of the preceding claims, wherein the porous catalytic capsules have a number-average diameter of between 1 µm and 1000 µm. A method according to any one of the preceding claims, wherein the solid particles added in step a) are silica particles. A process according to any one of the preceding claims, wherein the crosslinking agent added in step 1b) is selected from at least one silica precursor compound of the silicate or orthosilicate or silicic or orthosilicic or alkoxysilane type. A method according to any one of the preceding claims, wherein the mass ratio between the crosslinking agent and the solid particles is between 1 and 10. A process according to any one of the preceding claims, wherein the organic phase L1 comprises at least one or more saturated hydrocarbons selected from linear or cyclic alkanes, and / or one or more unsaturated hydrocarbons selected from olefins or aromatic compounds, alcohols, and aldehydes. A process according to any one of the preceding claims, wherein the organic phase L1 comprises at least one or more organic compounds having between 3 and 20 carbon atoms. A process according to any one of the preceding claims, wherein the organic phase L1 consists of said alkene. A process according to any one of the preceding claims, wherein the volume ratio between the liquid phase L2 and the organic liquid phase L1 is between 2:1 and 1:10.