Method for converting alkylfurans into alcohols and ketones

Abstract

The present invention relates to a method for preparing a compound of formula (I) and / or formula (I'), comprising the following steps: i) bringing a compound of formula (II) in which R2, R3, R4 and R5 are each independently selected from H, methyl and ethyl, into contact with a hydrogenation / hydrogenolysis metal catalyst, said contact taking place in a reaction medium heated to a temperature T1 greater than or equal to 90°C and pressurized to a partial pressure PH2 of hydrogen greater than or equal to 0.01 bar, and ii) forming a compound of formula (I) and / or a compound of formula (I'), R2, R3, R4 and R5 being as in the compound of formula (II).

Description

[0001] Process for converting alkylfurans into alcohols and ketones

[0002] The present invention relates to a process for converting alkylfurans, in particular 2,5-dimethylfuran, into alcohols, in particular 2-hexanol, and / or ketones, in particular 2-hexanone, exhibiting improved yields.

[0003] Decarbonizing the aviation sector requires the increasing use of renewable fuels (RFs), which have a significantly lower carbon footprint compared to the fossil fuels currently used. However, the quantities of raw materials currently used (used cooking oils, first-generation vegetable oils) to produce RFs are limited and will not be sufficient to meet the entire RF demand in the near future. These raw materials also require a cracking / isomerization step because the chain lengths of the resulting compounds are too long (C18) to improve the fuel's cold-weather performance.

[0004] It is therefore necessary to use other biomass sources to produce SAF, for example lignocellulosic biomass (wood, forestry residues, or agricultural byproducts). As its name suggests, lignocellulose is composed of cellulose, hemicellulose, and lignin. These components need to be separated before processing, this separation notably producing pulp carbohydrate (containing cellulose).

[0005] Cellulose can be used to produce SAF, but this requires a series of steps to convert it into products of interest (= C9-C18 alkanes). Several thermocatalytic pathways can be used, for example the conversion of cellulose to 2,5-dimethylfuran (DMF) followed by the conversion of DMF to 2-hexanol, or the conversion of hemicellulose to 2-methylfuran (MF) followed by the conversion of MF to 2-pentanol (a product that can be converted into C9-C18 alkanes).

[0006] However, other reactions can occur during the conversion of DMF / MF to 2-hexanol / 2-pentanol, including the formation of 2,5-dimethyltetrahydrofuran (DMTHF) / 2-methyltetrahydrofuran (MTHF), thus reducing the conversion rate of DMF / MF to products of interest, and therefore the SAF yield.

[0007] 2-Hexanone or 2-pentanone can also be formed, but this is less problematic because it can then be converted to 2-hexanol / 2-pentanol by hydrogenation of the C=O double bond. Furthermore, 2-hexanone / 2-pentanone is itself a product of interest for certain applications, as it can be used to form C-C bonds by condensation.

[0008] The aim of the invention is therefore to provide a process for converting alkylfurans, particularly 2,5-dimethylfuran / 2-methylfuran, into alcohols and / or ketones, particularly 2-hexanol / 2-pentanol and / or 2-hexanone / 2-pentanone, yielding higher yields of alcohols and / or ketones, particularly 2-hexanol / 2-pentanol and / or 2-hexanone / 2-pentanone, than prior art processes. There is thus a need for a process for converting alkylfurans, particularly 2,5-dimethylfuran / 2-methylfuran, into alcohols and / or ketones, particularly 2-hexanol and / or 2-hexanone, that minimizes the amount of by-products formed, especially hydrogenated cyclic compounds, particularly DMTHF / MTHF.

[0009] To this end, the invention relates to a process for preparing a compound of formula (I) and / or formula (I'), comprising the following steps: i) bringing into contact a compound of formula (II): in which R 2 , R3 , R 4 and R 5 are each independently chosen from H, methyl and ethyl, and a metallic hydrogenation / hydrogenolysis catalyst, this contact being carried out in a reaction medium heated to a temperature T1 greater than or equal to 90 °C and pressurized to a partial pressure PH2 of dihydrogen greater than or equal to 0.01 bar, and ii) the formation of a compound of formula (I) and / or a compound of formula (I'):

[0010] R 2 , R 3 , R 4 and R 5 being such that in the compound of formula (II).

[0011] Indeed, the inventors have surprisingly discovered that bringing the compound of formula (II) into contact with the hydrogenation / hydrogenolysis catalyst only after the reaction medium has been heated to temperature T1 significantly reduces the amount of unwanted hydrogenated cyclic compounds, and consequently significantly increases the selectivity and therefore the yield of compounds of formula (I) and / or (I').

[0012] In particular, the invention relates to a process for preparing a compound of formula (I) and / or formula (I'), comprising the following steps:

[0013] A) i) the contacting of a compound of formula (II):

[0014] ® in which R 2 , R 3 , R 4 and R 5are each independently chosen from H, methyl and ethyl, and a metallic hydrogenation / hydrogenolysis catalyst, this contact being carried out in a reaction medium heated to a temperature T1 greater than or equal to 90 °C and pressurized to a partial pressure PH2 of dihydrogen greater than or equal to 0.01 bar, and ii) the formation of a mixture of a compound of formula (I) and a compound of formula (I'):

[0015] R 2 , R 3 , R 4 and R 5 being such that in the compound of formula (II); and

[0016] B) a step d) of hydrogenation of the compound of formula (I') present in the mixture from step ii) in the presence of a metallic hydrogenation catalyst, the metallic hydrogenation catalyst being different from the metallic hydrogenation / hydrogenolysis catalyst of step i).

[0017] Preferably, the process includes, prior to step i), a step of preparing the reaction medium heated to a temperature T1 greater than or equal to 90 °C and pressurized to a partial pressure PH2 of dihydrogen greater than or equal to 0.01 bar. Before step i), this reaction medium may therefore include the metal hydrogenation / hydrogenolysis catalyst or the compound of formula (II), but does not contain both together (since they have not yet been brought into contact). Preferably, R 2 , R 3 , R 4 and R 5 are each independently chosen from H and a methyl.

[0018] Preferably, at least two out of R 2 , R 3 , R 4 and R 5 are hydrogens.

[0019] Preferably, R 3 = R 4 = H and R 2 and R 5 are independently chosen from H, methyl and ethyl, preferably H and methyl.

[0020] Advantageously, the compound of formula (II) is 2,5-dimethylfuran or 2-methylfuran.

[0021] Preferably, the temperature T1 is the temperature at which the conversion reaction of the compound of formula (II) into the compound of formula (I) and / or (I') takes place. Preferably, the temperature T1 ranges from 90°C to 300°C, preferably from 110°C to 260°C, preferably from 130°C to 240°C, preferably from 140°C to 230°C, preferably from 150°C to 220°C, preferably from 160°C to 210°C, preferably from 170°C to 210°C.

[0022] The hydrogen pressure PH2 corresponds to the partial pressure of H2 in the reaction medium. The hydrogen pressure PH2 can be either the partial pressure of H2 at the start of the reaction (particularly in batch processes) or the partial pressure of H2 throughout the reaction (particularly in continuous processes). Preferably, the hydrogen pressure PH2 ranges from 0.1 bar to 20 bar, preferably from 0.5 bar to 15 bar, preferably from 1.0 bar to 12 bar, preferably from 2.0 bar to 10 bar, preferably from 3.0 bar to 8.0 bar, and preferably from 3.0 bar to 5.0 bar.

[0023] 1 bar corresponds to 10 5 Pa.

[0024] A metallic catalyst is defined as a catalyst comprising at least one metal.

[0025] By hydrogenation / hydrogenolysis catalyst, we mean a catalyst capable of catalyzing a dihydrogenation reaction, for example of a C=C bond (to become a single CH-CH bond) or of a C=O bond (to become a single CH-OH bond) in the presence of dihydrogen and a hydrogenolysis reaction, for example of a C-O bond (to become two different bonds, CH and HO).

[0026] Preferably, the metal catalyst for hydrogenation / hydrogenolysis comprises a metal selected from Cr, Mo, W, Re, Mn, Cu, Cd, Fe, Ru, Os, Ir, Co, Rh, Pt, Pd, Ni and their alloys or combinations, preferably selected from Re, Cu, Fe, Ru, Os, Ir, Co, Rh, Pt, Pd, and Ni, more preferably selected from Ru, Rh, Pt, and Pd, advantageously platinum. These metals may optionally be used with promoters such as Au, Ag, Cr, Zn, Mn, Sn, Bi, B, O and their alloys or combinations.These catalysts may also have an active phase selected from (i) metals, oxides, phosphides or sulfides of Ni, Mo, W, Co or mixtures of NiCo, NiW, NiMo, C0M0, NiCoW, NiCoMo, NiMoW and CoMoW, preferably comprising molybdenum or nickel, preferably molybdenum, preferably comprising nickel, cobalt, molybdenum, tungsten or mixtures thereof, preferably comprising oxides, sulfides or phosphides of nickel, cobalt, molybdenum, tungsten or mixtures thereof, preferably the catalyst is selected from NiMoS, CoMoS and Ni. 3x P y , where the x / y ratio is between 0.3 and 3, advantageously from NiMoS and CoMoS, (ii) metals or mixtures of metal alloys from Group 10 and Group 11 of the periodic table. Alternatively, the catalyst is Ni-P.

[0027] Preferably, the metallic hydrogenation / hydrogenolysis catalyst is supported. The support is preferably chosen from carbon supports (activated carbon, carbon black, carbon nanofibers, carbon nanotubes, fullerenes), silica, alumina, zirconia oxide, titanium oxide, zinc oxide, zeolites, and any combination thereof, preferably a carbon support.

[0028] It is preferable for the substrate to have a high specific surface area. In one embodiment, the specific surface area must be at least 75 m². 2 / g, preferably at least 150 m 2 / g and more preferably at least 200 m 2 / g, this specific surface area can be measured by methods known in the art such as the BET method where the adsorption of nitrogen allows the specific surface area of ​​the solid material to be estimated.

[0029] Preferably, the metallic hydrogenation / hydrogenolysis catalyst is supported, and has a metal content ranging from 0.1% by mass to 70% by mass, relative to the total mass of the metallic hydrogenation / hydrogenolysis catalyst, preferably from 0.2% to 60% by mass, preferably from 0.5% to 50% by mass, preferably from 1.0% to 30% by mass, preferably from 2.5% to 15% by mass, preferably from 3.0% to 12% by mass.

[0030] Preferably, the metallic hydrogenation / hydrogenolysis catalyst is supported, and has a dispersion of the metal on the support ranging from 1.2% to 90%, preferably from 2.0% to 75%, preferably from 2.5% to 50%, preferably from 3.0% to 20%, preferably from 3.0% to 15%, preferably from 3.5% to 12%, preferably between 3.8% and 10%; or advantageously from 1.2% to 20%, more advantageously from 2.0% to 15%.

[0031] The dispersion D of the metal hydrogenation / hydrogenolysis catalyst is the fraction of metal atoms of the catalyst exposed at its surface. D = (N_S) / (N_T), where (N_S) is the number of surface metal atoms and (N_T) is the total number of metal atoms in the catalyst. D is determined by CO chemisorption according to the following protocol:

[0032] The metallic catalysts were characterized by CO chemisorption on the AMI-300 chemisorption analyzer (3P Instruments) with a thermal conductivity detector (TCD). Typically, 50 mg of catalyst are loaded into a tubular reactor and pretreated in a 25 mL / min He flow at 150°C (ramp: 10°C min⁻¹). -1 ) for 20 min to remove adsorbed water. Then, the catalyst is treated in a 5% H2 (in N2) stream at 25 mL / min at 200°C (ramp: 10°C min -1 ) for 2 hours and is then cooled to room temperature in He.

[0033] For the (N_S) measurement, CO pulses were delivered at 2.5-minute intervals in a 40 °C He stream. The amount of CO absorbed per mass of catalyst (NCO, in mol / g) was calculated based on the calibration of the saturated CO pulses. Assuming a 1:1 stoichiometry for each catalyst, the metal dispersion (D) was automatically calculated using the AMI-300 analysis software, taking into account the metal loading ( / W%), the molecular weight of the metal ( / Wl / I / ) according to the following relationship:

[0034] 100 x MW

[0035] According to one embodiment, the process comprises the following steps: a) the preparation of a reaction medium heated to a temperature T1 greater than or equal to 90 °C and pressurized to a partial pressure PH2 of dihydrogen greater than or equal to 0.01 bar, the reaction medium comprising a metal hydrogenation / hydrogenolysis catalyst and optionally a solvent, and obtaining a heated and pressurized reaction medium, b) the introduction of a compound of formula (II) as defined above into the heated and pressurized reaction medium obtained in step a), preferably the introduction of 2,5-dimethylfuran or 2-methylfuran, optionally in a mixture with a solvent, and c) the formation of a compound of formula (I) and / or a compound of formula (I') as defined above, preferably the formation of 2-hexanol and / or 2-hexanone, or 2-pentanol and / or 2-pentanone.

[0036] Preferably, step c) is the formation of a mixture of a compound of formula (I) and a compound of formula (I') as defined above, preferably the formation of a mixture of 2-hexanol and 2-hexanone, or a mixture of 2-pentanol and 2-pentanone.

[0037] According to one embodiment, the reaction medium of step a) comprises a solvent.

[0038] According to another embodiment, the compound of formula (II) is mixed with a solvent during step b). According to another embodiment, both the reaction medium of step a) comprises a solvent and the compound of formula (II) is mixed with a solvent during step b). The solvent of step a) and the solvent of step b) may be the same or different.

[0039] Preferably, step a) comprises a substep a1) of preparing a reaction medium including the metal hydrogenation / hydrogenolysis catalyst and optional solvent, followed by a substep a2) of heating this reaction medium to a temperature T1 greater than or equal to 90 °C, and a substep a3) of pressurizing the reaction medium to a hydrogen pressure PH2 greater than or equal to 0.01 bar. Substep a1) necessarily takes place before substeps a2) and a3), but substeps a2) and a3) may be carried out one after the other in either order, or even simultaneously.

[0040] Preferably, the reaction medium obtained at the end of substep a1) is first heated according to substep a2), then pressurized according to substep a3).

[0041] In the case of a process carried out continuously, it is preferable that the reaction medium of step a) be a reactor comprising a supported catalyst, for example a heated and pressurized fixed-bed reactor, and step b) then comprises the introduction of the compound of formula (II), preferably in a mixture with a solvent, into this reactor.

[0042] According to another embodiment, the process comprises the following steps: a') preparing a reaction medium heated to a temperature T1 greater than or equal to 90 °C and pressurized to a partial pressure PH2 of dihydrogen greater than or equal to 0.01 bar, the reaction medium comprising a solvent and a compound of formula (II) as defined above, preferably the introduction of 2,5-dimethylfuran or 2-methylfuran, and obtaining a heated and pressurized reaction medium; b') introducing a metal hydrogenation / hydrogenolysis catalyst, optionally in solution or in suspension in a solvent, into the heated and pressurized reaction medium obtained in step a); and c') forming a compound of formula (I) and / or a compound of formula (I') as defined above, preferably the formation of 2-hexanol and / or 2-hexanone, or 2-pentanol and / or 2-pentanone.

[0043] Preferably, c') is the formation of a mixture of a compound of formula (I) and a compound of formula (I') as defined above, preferably the formation of a mixture of 2-hexanol and 2-hexanone, or a mixture of 2-pentanol and 2-pentanone. Preferably, step a') comprises a substep aT) of preparing a reaction medium comprising the solvent and the compound of formula (II), followed by a substep a2') of heating this reaction medium to a temperature T1 greater than or equal to 90 °C, and a substep a3') of pressurizing the reaction medium to a hydrogen pressure PH2 greater than or equal to 0.01 bar. Substep aT) necessarily takes place before substeps a2') and a3'), but substeps a2') and a3') can be carried out one after the other in one order or in the other, or even simultaneously.

[0044] Preferably, the reaction medium obtained at the end of substep aT) is first heated according to substep a2'), then pressurized according to substep a3').

[0045] Preferably, the solvent is chosen from C6-C20 alkanes, C1-C10 alcohols, and C3-C10 ketones, preferably from linear C6-20 alkanes, primary or secondary linear C3-C10 alcohols, preferably C3-C6, and linear C3-C10 alkanones, preferably C3-C6, or any mixture thereof, more preferably from linear C6-20 alkanes.

[0046] The solvent is preferably chosen from dodecane, tetradecane, hexadecane, octadecane, eicosan, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 2-propanol, 2-butanol, 2-pentanol, 2-hexanol, acetone, 2-butanone, 2-pentanone, 2-hexanone, advantageously is dodecane, hexadecane, 2-hexanol, 2-hexanone or a mixture of 2-hexanol and 2-hexanone or a mixture of 2-pentanol and 2-pentanone.

[0047] Obtaining the compound of formula (I) and / or the compound of formula (I'), preferably a mixture thereof, during step ii) or c) or c') results from the reaction between the compound of formula (II) and dihydrogen, catalyzed by the metal hydrogenation / hydrogenolysis catalyst.

[0048] Advantageously, under the conditions described above, the compound of formula (II), and preferably the solvent if present, are in the liquid state. Thus, preferably, the obtaining of the compound of formula (I) and the compound of formula (I') during step ii) or c) or c') results from the liquid-phase reaction between the compound of formula (II) and dihydrogen, catalyzed by the metal hydrogenation / hydrogenolysis catalyst.

[0049] Preferably, step ii) or c) or c') (i.e., the reaction between compound of formula (II) and dihydrogen, catalyzed by the metal hydrogenation / hydrogenolysis catalyst) takes place over a period of 5 minutes to 5 hours. These durations are preferably valid when the process is carried out in batches. In continuous operation, step ii) or c) or c') (i.e., the reaction between compound of formula (II) and dihydrogen, catalyzed by the metal hydrogenation / hydrogenolysis catalyst) is carried out with a contact time, expressed as WHSV, between 0.1 and 100 h -1 (WHSV stands for weight hourly space velocity or the mass flow rate of the feed (in kg / h) relative to the mass of the catalyst (in kg). In continuous mode, the partial pressure of dihydrogen can be controlled and optimized by staged injection of dihydrogen at different heights of the fixed catalytic bed.

[0050] The above conditions are advantageous because they reduce the formation of dihydrogenated cyclic products (in particular DMTHF in the case of a 2,5-dimethylfuran conversion process or MTHF in the case of a 2-methylfuran conversion process), thereby increasing the yield of compound (I) and compound (I') (in particular 2-hexanol and / or 2-hexanone, or 2-pentanol and / or 2-pentanone). Having achieved this initial optimization, the inventors further investigated the process to develop more specific conditions that, in addition to optimizing the yield, promote the production of either compound (I) or compound (I') (in particular 2-hexanol or 2-hexanone, or 2-pentanol or 2-pentanone).

[0051] Indeed, according to some embodiments, step ii) or c) or c') of the process provides a mixture of compound of formula (I) and compound of formula (I'), in proportions that vary according to the conditions.

[0052] According to a particular embodiment, the metallic hydrogenation / hydrogenolysis catalyst is supported, and has a dispersion of the metal on the support ranging from 2.0% to 9.0%, preferably from 2.5% to 8.0%, preferably from 3.0% to 7.0%, preferably between 3.5% and 6.0%, preferably between 4.0% and 5.0%.

[0053] Without wanting to be bound by any theory, the inventors believe that catalysts with a different dispersion will have a different capacity to hydrogenate the compound of formula (I') (preferably 2-hexanone or 2-pentanone), favoring or not the formation of the compound of formula (I) (preferably 2-hexanol or 2-pentanol) (the more a catalyst is able to hydrogenate the compound of formula (I'), the higher the ratio (l) / (l') will be).

[0054] According to another particular embodiment or in addition, the partial pressure of dihydrogen is maintained constant at the value PH2 during the implementation of the process according to the invention, in particular during step ii) or c) or c'). This is made possible by a continuous supply of dihydrogen in the reaction medium, in particular during step ii) or c) or c').

[0055] According to another embodiment, the process according to the invention comprises the following steps:

[0056] A) steps i) and ii), or steps a), b) and c), or steps a'), b') and c'), as described above, step ii) or c) or c') forming a mixture of compound of formula (I) and compound of formula (I'), preferably of 2-hexanol and 2-hexanone or of 2-pentanol and / or 2-pentanone, and

[0057] B) a step d) of hydrogenating the compound of formula (I'), preferably of 2-hexanone (or 2-pentanone), present in the mixture from step ii), or c) or c').

[0058] Preferably, according to this embodiment, step d) is carried out in the presence of a metallic hydrogenation catalyst. Preferably, the metallic hydrogenation catalyst is different from the metallic hydrogenation / hydrogenolysis catalyst of step i) or a) or b'). The metallic hydrogenation catalyst is preferably a metallic hydrogenation catalyst having a higher catalytic power for the hydrogenation of a C=O bond than that of the metallic hydrogenation / hydrogenolysis catalyst of step i) or a) or b').

[0059] By "higher catalytic power of hydrogenation of a C=O bond", we mean i) either that the rate of conversion to hydrogenated molecules (i.e., containing a CH-OH fragment) obtained from molecules containing a C=O bond, under the reaction conditions of step d), in particular pressure and temperature as described below, is higher for the metal hydrogenation catalyst than for the metal hydrogenation / hydrogenolysis catalyst of step i) or a) or b'), all other reaction conditions being identical, ii) or that the time to achieve an identical rate of conversion to hydrogenated molecules (i.e., containing a CH-OH fragment) obtained from molecules containing a C=O bond, under the reaction conditions of step d), in particular pressure and temperature as described below,is lower for the metallic hydrogenation catalyst than for the metallic hydrogenation / hydrogenolysis catalyst of step i) or a) or b'), all other reaction conditions being identical. This property depends on the nature of the catalyst, and is notably related to the rate of conversion by the catalyst of molecules containing a C=O bond, and to the selectivity of the catalyst for the hydrogenation reaction.

[0060] Preferably, the metal hydrogenation catalyst comprises a metal selected from Cr, Mo, W, Re, Mn, Cu, Cd, Fe, Ru, Os, Ir, Co, Rh, Pt, Pd, Ni and their alloys or combinations, preferably chosen from Re, Cu, Fe, Ru, Os, Ir, Co, Rh, Pt, Pd, and Ni, more preferably chosen from Ru, Rh, Pt, and Pd, advantageously ruthenium. Preferably, the metal hydrogenation catalyst is supported. The support is preferably chosen from carbonaceous supports (activated carbon, carbon black, carbon nanofibers, carbon nanotubes, fullerenes), silica, alumina, zinc oxide, zeolites, and any combination thereof, preferably a carbonaceous support.

[0061] It is preferable for the substrate to have a high specific surface area. In one embodiment, the specific surface area must be at least 75 m². 2 / g, preferably at least 150 m 2 / g and more preferably at least 200 m2 / g, this specific surface area can be measured by methods known in the art such as the BET method where the adsorption of nitrogen allows the specific surface area of ​​the solid material to be estimated.

[0062] Preferably, the metallic hydrogenation catalyst comprises from 0.6% by mass to 50% by mass, relative to the total mass of the metallic hydrogenation catalyst, preferably from 0.8% to 30% by mass, preferably from 1.5% to 20% by mass, preferably from 2.0% to 15% by mass, preferably from 2.5% to 12% by mass.

[0063] Preferably, step d) is carried out at a temperature T2 between 40°C and 150°C, preferably between 60°C and 120°C, preferably between 70°C and 90°C.

[0064] Preferably, hydrogenation step d) takes place over a period of 5 minutes to 5 hours. These durations are preferably valid for a batch process. In continuous operation, step d) is carried out with a contact time, expressed as a WHSV, between 0.1 and 100 h -1 (WHSV means weight hourly space velocity or the mass flow rate of the charge (in kg / h) relative to the mass of the catalyst (in kg).

[0065] Preferably, step d) is a liquid phase hydrogenation step.

[0066] Preferably, step d) includes a substep d1) of contacting the mixture obtained at the end of step ii) or c) or c') with the hydrogenation catalyst to obtain a second reaction medium.

[0067] This contacting can be carried out by adding the hydrogenation catalyst to the mixture obtained at the end of step ii) or c) or c'), or by transferring the mixture obtained at the end of step ii) or c) or c') into a reactor including the hydrogenation catalyst.

[0068] According to one embodiment, step d) comprises a substep d2) of heating the second reaction medium to a temperature T2 between 40°C and 150°C, preferably between 60°C and 120°C, preferably between 70°C and 90°C, and / or a substep d3) of pressurizing the second reaction medium to a partial pressure PH2-2 ranging from 1.0 bar to 15 bar, preferably from 1.5 bar to 12 bar, preferably from 2.0 bar to 7.0 bar, preferably from 3.0 bar to 6.0 bar. Substep d1) preferably takes place before substeps d2) and d3), but substeps d2) and d3) may be carried out one after the other in either order, or even simultaneously. This embodiment is preferred when step d) includes the addition of the hydrogenation catalyst to the mixture obtained at the end of step ii) or c) or c').Substep d1) may be preceded by a substep d0) of decreasing the temperature of the mixture obtained at the end of step ii) or c) or c') down to temperature T2.

[0069] According to another embodiment, step d) includes transferring the mixture obtained at the end of step ii) or c) or c') into a reactor comprising the second hydrogenation catalyst, this reactor being able to be preheated and / or pressurized to the temperature and pressure as described for the preceding embodiment. In this case, steps d2) of heating the reactor comprising the hydrogenation catalyst and / or d3) of pressurizing the reactor comprising the hydrogenation catalyst are carried out before step d1).

[0070] The above embodiments make it possible to favour the formation of the compound of formula (I), in particular of 2-hexanol (or 2-pentanol), compared to the formation of the compound of formula (I'), in particular of 2-hexanone (or 2-pentanone).

[0071] According to another embodiment, the metallic hydrogenation / hydrogenolysis catalyst (step i), a) or b')) is supported, and has a dispersion of the metal on the support ranging from 4.0% to 40%, preferably from 6.0% to 20%, preferably from 7.0% to 15%, preferably between 8.0% and 12%, preferably between 9.0% and 10%.

[0072] Preferably, the temperature T1 ranges from 190°C to 220°C, preferably from 190°C to 210°C.

[0073] Preferably, step ii) or c) or c') (i.e., the reaction between compound of formula (II) and dihydrogen, catalyzed by the metal hydrogenation / hydrogenolysis catalyst) takes place over a period of 1 to 60 minutes, preferably 2 to 30 minutes, preferably 3 to 20 minutes, and preferably 5 to 15 minutes. These durations are preferably valid when the process is carried out in batches. In continuous operation, step ii) or c) or c') (i.e., the reaction between compound of formula (II) and dihydrogen, catalyzed by the metal hydrogenation / hydrogenolysis catalyst) is carried out with a contact time, expressed as WHSV, between 0.1 and 100 h -1 (WHSV stands for weight hourly space velocity or the mass flow rate of the feed (in kg / h) relative to the mass of the catalyst (in kg), preferably from 0.5 to 50 or preferably from 1 to 10 h -1 .

[0074] Preferably, the process further comprises a step e) of conversion of the compound of formula (I) from step d) into hydrocarbon(s), preferably C9-C20, preferably C9-C18, preferably C12-C18, said step e) comprising a substep e1) of oligomerization and a substep e2) of hydrogenation, step e1) being carried out before or after step e2).

[0075] According to one embodiment, substep e1) of oligomerization is carried out before substep e2) of hydrogenation.

[0076] According to this embodiment, the process comprises: e1) an oligomerization step of the compound of formula (I) from step d), to obtain at least one oligomer of compounds of formula (I), preferably in C9-C20, preferably in C9-C18, preferably in C12-C18, then e2) a hydrogenation step of the at least one oligomer from step e) to obtain at least one hydrocarbon, preferably in C9-C20, preferably in C9-C18, preferably in C12-C18.

[0077] According to another embodiment, substep e2) of hydrogenation takes place before substep e1) of oligomerization.

[0078] According to this other embodiment, the process comprises: e2) a hydrogenation step of the compound of formula (I) from step d) to obtain at least one hydrocarbon in C5-C7, preferably in C6, then e1) an oligomerization step of at least one hydrocarbon from step e), to obtain at least one hydrocarbon, preferably in C9-C20, preferably in C9-C18, in C9-C18, preferably in C12-C18.

[0079] The oligomerization substep e1) may advantageously include the dehydration of the compound of formula (I) and the oligomerization of the dehydrated product.

[0080] The invention also relates to a process for producing jet fuel, in particular renewable jet fuel, comprising at least one hydrocarbon, preferably C9-C20, preferably C9-C18, preferably C12-C18, said process comprising: A) steps i) and ii) as described above, or steps a), b) and c) as described above, or steps a'), b') and c') as described above, step ii), c) or c') forming a compound of formula (I) and / or a compound of formula (I'); optionally B) a step d) of hydrogenating the compound of formula (I'), if it is present in a mixture from step ii) or c) or c'), said step being as described above, step d) forming a hydrogenated mixture comprising a compound of formula (I); and

[0081] C) a step e) of converting the hydrogenated mixture from step A) and / or B) into hydrocarbon(s), preferably C9-C20, preferably C9-C18, preferably C12-C18, said step being as described above, to obtain the fuel.

[0082] Preferably, the process for producing jet fuel includes:

[0083] A) steps i) and ii) as described above, or steps a), b) and c) as described above, or steps a'), b') and c') as described above, step ii), c) or c') forming a mixture of a compound of formula (I) and a compound of formula (I');

[0084] B) a step d) of hydrogenating the compound of formula (I') present in the mixture from step ii) or c) or c'), said step being as described above, step d) forming a hydrogenated mixture comprising a compound of formula (I); and

[0085] C) a step e) of converting the hydrogenated mixture from step d) into hydrocarbon(s), preferably C9-C20, preferably C9-C18, preferably C12-C18, said step being as described above, to obtain jet fuel.

[0086] Preferably, the process for producing jet fuel includes, after step e), one or more purification and / or fractionation steps.

[0087] Preferably, the process according to the invention is implemented in batches (in batch, according to the commonly used English terminology) or continuously.

[0088] The expressions "between ... and ..." and "ranging from ... to ..." should be understood inclusive of limits, unless otherwise specified.

[0089] The following examples will help to better understand the invention, but are not intended to be exhaustive.

[0090] EXAMPLES For each test, the crude reaction product was analyzed by GC-FID, allowing the molar content of each compound to be determined.

[0091] GC-FID analysis conditions:

[0092] Quantitative analysis of the products was performed on an Agilent Technologies 6890N GC equipped with an Agilent Technologies 7689 Series autosampler, a DB-17 column (length: 30 m, diameter: 0.32 mm, film thickness: 0.5 µm), and a FID detector. 1,4-Dioxane was used as an external standard. The analytical conditions were as follows: N2 flow rate 10 mL / min, division ratio 5:1, injector temperature 280°C; oven temperature program: 50°C, hold 3 min, 50–80°C (ramp 5°C / min), hold 8 min, 80–250°C (ramp 10°C / min), hold 3 min; detector temperature 320°C.

[0093] The conversion, selectivity, and yield to products were calculated as follows:

[0094] DMF Mole Converted

[0095] Conversion (%) = x 100%

[0096] DMF Mole initially introduced

[0097] Molecule of the desired product(s)

[0098] Selectivity (%) = x 100% Mole of all products obtained

[0099] Molecule of the desired product(s)

[0100] Yield (%) x 100% Mole of DMF introduced initially

[0101] For the reactions in examples 5 to 8, 0.3 g of heptane were introduced into the reaction medium at the beginning of the reaction, as an internal standard.

[0102] Example 1: Influence of heating the reaction medium before introduction of DMF In this example, two processes were compared: a process 1 according to the invention in which DMF is added to the reaction medium, the latter being at the desired reaction temperature, and a comparative process 2 in which DMF is introduced into the reaction medium at room temperature, before heating to the target reaction temperature.

[0103] Details of the two processes:

[0104] Process 1 (comparative): 0.3 g of DMF, 0.1 g of dry metal hydrogenation / hydrogenolysis catalyst, and 40 mL of dodecane (or other solvent) were loaded into a batch reactor (Parr®, 100 mL, Parr Instrument Company, Moline, IL, USA). The reactor was purged with N2 to replace the air inside and then pressurized with H2 (e.g., 2.5–10 bar) at room temperature. The mixture was then stirred (300–800 rpm). A temperature program was followed from room temperature to the set temperature (this time was not included in the reaction time calculation). After the reaction time, the reactor was placed in ice water for rapid cooling (average cooling rate of 10 °C / min). -1 ), depressurized to 25 °C and opened for analysis. The products were analyzed by GC-FID.

[0105] Process 2 (invention): 0.1 g of dry metal hydrogenation / hydrogenolysis catalyst and 38 mL of dodecane (or other solvent) were introduced into a batch reactor. The reactor was purged with N2 to replace the air inside and then pressurized with H2 (e.g., 2.5–10 bar) at room temperature. The mixture was then stirred (300–800 rpm). A temperature program was followed from room temperature to the setpoint temperature (this time was not included in the reaction time calculation). Once the setpoint temperature was reached, a DMF solution (2 mL containing 15% by mass of DMF, i.e., 0.3 g) in dodecane (or other solvent), with or without an internal standard, was introduced into the reactor using an HPLC pump (Waters 515 HPLC pump) for 60 seconds. After the reaction time, the reactor was placed in ice water for rapid cooling (average cooling rate of 10 °C min⁻¹).1 ), depressurized to 25 °C and opened for analysis. The products were analyzed by GC-FID.

[0106] Variables: process and temperature

[0107] Fixed conditions: DMF = 0.3 g, Pt / C (5 wt%) = 0.1 g, p(H2) = 5 bar, dodecane = 30 g, reaction time = 3 h, stirring speed = 800 rpm

[0108] The results obtained are presented in Table 1 below. The DMF conversion rate is 100% for each trial.

[0109] [Table 1]

[0110] : comparison

[0111] These results show that at a reaction temperature of 80°C, the content of the products obtained differs little depending on the process used. However, as the temperature increases, the quantity of DMTHF produced decreases substantially when process 2 according to the invention is implemented, compared to the implementation of the comparative process 1, which allows for yields of up to 91% of 2-hexanol and 2-hexanone (test 1.4). These results therefore demonstrate that introducing DMF into a reaction medium already at the target reaction temperature, rather than at ambient temperature, significantly improves the selectivity of the process for obtaining 2-hexanol and 2-hexanone.

[0112] Example 2: Influence of reaction temperature

[0113] Process 2 described in Example 1 was implemented at different reaction temperatures.

[0114] Variable: temperature

[0115] Fixed conditions: DMF = 0.3 g, Pt / C (5 wt%) = 0.1 g, p(H2) = 5 bar, dodecane = 30 g, reaction time = 3 h, stirring speed = 800 rpm; Process 2 of Example 1

[0116] The results obtained are presented in Table 2 below. The conversion of

[0117] DMF is 100% for each trial.

[0118] [Table 2]

[0119] : comparison

[0120] A temperature above 90°C is required to improve selectivity in 2-hexanol and 2-hexanone, preferably between 110°C and 260°C, preferably between 130°C and 240°C, preferably between 140°C and 230°C, preferably between 150°C and 220°C, preferably between 160°C and 210°C, preferably between 170°C and 210°C.

[0121] Example 3: Influence of dihydrogen pressure

[0122] Process 2 described in Example 1 was implemented at different hydrogen pressures.

[0123] Variables: temperature and pressure

[0124] Fixed conditions: DMF = 0.3 g, Pt / C (5 wt%) = 0.1 g, dodecane = 30 g, reaction time = 3 h, stirring speed = 800 rpm; Process 2 of Example 1

[0125] The results obtained are presented in Table 3 below. The DMF conversion rate is 100% for each trial.

[0126] [Table 3]

[0127] These results show that a lower dihydrogen pressure than in examples 1 and 2 still improves the conversion to 2-hexanol and 2-hexanone.

[0128] Example 4: Influence of the nature of the solvent

[0129] Process 2 described in example 1 was implemented in two different solvents.

[0130] Variable: solvent

[0131] Fixed conditions: DMF = 0.3 g, Pt / C (5 % mass) = 0.1 g, solvent = 30 g, T = 180 °C, H2 pressure = 5 bars, reaction time = 3 h, stirring = 800 rpm; Process 2 of example 1.

[0132] The results obtained are presented in Table 4 below. The DMF conversion rate was 100% for each trial. [Table 4]

[0133] These results show that alkanes, preferably linear, having at least 10 carbon atoms, are suitable solvents for implementing the process according to the invention.

[0134] Example 5: Influence of the Pt / C catalyst

[0135] Process 2 described in Example 1 was implemented with different Pt / C catalysts (platinum supported on activated carbon), having different Pt mass contents. The different tests were carried out at an equivalent DM F / Pt mass ratio.

[0136] Variable: Pt / C catalyst

[0137] Fixed conditions: DMF = 0.3 g, DMF / Pt mass ratio = 60, dodecane = 30 g, T = 180 °C, H2 pressure = 5 bar, reaction time = 3 h, stirring speed = 800 rpm; Process 2 of Example 1

[0138] The dispersion of Pt in the catalysts was determined by CO chemisorption.

[0139] The acidity of the catalyst was determined by NH3-TPD.

[0140] The results obtained are presented in Table 5 below:

[0141] [Table 5] These results show that all other Pt / C catalysts maximize the yield of 2-hexanol and 2-hexanone, while decreasing the amount of DMTHF formed.

[0142] These results also illustrate that catalysts with different dispersion values ​​produce mixtures with very different 2-hexanol:2-hexanone ratios, which allows the appropriate catalyst to be chosen according to the desired composition of the final product.

[0143] Example 6: Optimization of 2-hexanol selectivity - Influence of H2 supply method

[0144] Process 2 described in Example 1 was implemented either by charging the reactor once at room temperature with dihydrogen, or by providing a continuous supply of dihydrogen to maintain a constant pressure inside the reactor throughout the reaction. Two catalysts with different Pt contents were tested at two different H2 pressures.

[0145] Variables: H2 supply method, H2 pressure, Pt content of the catalyst. Fixed conditions: DMF = 0.3 g, catalyst = Pt / C, DMF / Pt mass ratio = 60, dodecane = 30 g, T = 180 °C, reaction time = 3 h, stirring = 800 rpm. Process 2 of example 1.

[0146] The results obtained are presented in Table 6 below. The DMF conversion rate is 100% for each trial.

[0147] [Table 6]

[0148] These results show that continuous H2 supply improves 2-hexanol selectivity. Example 7: Optimization of 2-hexanol selectivity - Two-step process

[0149] In this example, the first step of converting DM F into 2-hexanol / 2-hexanone was coupled with a subsequent second step of converting the 2-hexanone formed at the end of the first step into 2-hexanol.

[0150] For each reaction, process 2 of example 1 was therefore implemented, followed by a cooling step to room temperature, the addition of 0.1 g of Ru / C (5 wt% metal) into the reaction medium, the re-pressurization of the medium under 5 bar of dihydrogen and the stirring of the mixture for 2 hours.

[0151] Variables:

[0152] First step A: duration of the reaction, Pt content of the catalyst.

[0153] Fixed conditions:

[0154] First step A: DM F = 0.3 g, catalyst = Pt / C, mass ratio DMF / Pt = 60, dodecane = 30 g, H2 pressure = 5 bars, T = 180 °C, reaction time = 3 h, stirring = 800 rpm, Process 2 of example 1;

[0155] Second step B: catalyst = Ru / C, Ru / C (5 % mass) = 0.1 g, H2 pressure = 5 bars, T = 80 °C, reaction time = 2 h, stirring = 800 rpm.

[0156] The results obtained are presented in Table 7 below. The conversion of

[0157] DMF is 100% for each trial.

[0158] [Table 7]

[0159] These results show that adding a hydrogenation / hydrogenolysis step to the crude reaction product obtained after the first DMF conversion step yields almost exclusively 2-hexanol. By carefully selecting the conditions for this second step, it is possible to drastically reduce the reaction time of the first step, even though a majority of the product is 2-hexanone.

[0160] Example 8: Optimization of 2-hexanone selectivity - Influence of temperature and reaction time

[0161] To promote the formation of 2-hexanone, and as indicated by the results of example 5, the catalyst with 5% by mass of metal was chosen, i.e. the one exhibiting the highest dispersion.

[0162] Process 2 described in example 1 was implemented by varying the reaction time and reaction temperature.

[0163] Variables: reaction temperature, reaction time

[0164] Fixed conditions: DM F = 0.3 g, catalyst = Pt / C, Pt / C (5 % mass) = 0.1 g, dodecane = 30 g, H2 pressure = 2.5 bars, stirring = 300 rpm, process 2 of example 1.

[0165] The results obtained are presented in Table 8 below. The DMF conversion rate is 100% for each trial.

[0166] [Table 8]

[0167] A short reaction time and a slight increase in reaction temperature allows us to obtain a mixture consisting almost exclusively of 2-hexanone.

Claims

DEMANDS 1. A process for preparing a compound of formula (I) and / or formula (I'), comprising the following steps: A) i) the contacting of a compound of formula (II): in which R 2 , R 3 , R 4 and R 5 are each independently chosen from H, methyl and ethyl, and a metallic hydrogenation / hydrogenolysis catalyst, this contact being carried out in a reaction medium heated to a temperature T1 greater than or equal to 90 °C and pressurized to a partial pressure PH2 of dihydrogen greater than or equal to 0.01 bar, and ii) the formation of a mixture of a compound of formula (I) and a compound of formula (I'): 0) (O R 2 , R 3 , R 4 and R 5 being such that in the compound of formula (II); and B) a step d) of hydrogenation of the compound of formula (I') present in the mixture from step ii) in the presence of a metallic hydrogenation catalyst, the metallic hydrogenation catalyst being different from the metallic hydrogenation / hydrogenolysis catalyst of step i).

2. A method according to claim 1, wherein the temperature T1 ranges from 90°C to 300°C, preferably from 110°C to 260°C, preferably from 130°C to 240°C, preferably from 140°C to 230°C, preferably from 150°C to 220°C, preferably from 160°C to 210°C, preferably from 170°C to 210°C.

3. A method according to claim 1 or 2, wherein the hydrogen pressure PH2 ranges from 0.1 bar to 20 bar, preferably from 0.5 bar to 15 bar, preferably from 1.0 bar to 12 bar, preferably from 2.0 bar to 10 bar, preferably from 3.0 bar to 8.0 bar, preferably from 3.0 bar to 5.0 bar.

4. A process according to any one of the preceding claims, wherein the metal hydrogenation / hydrogenolysis catalyst comprises at least one metal selected from Re, Cu, Fe, Ru, Os, Ir, Co, Rh, Pt, Pd, and Ni, more preferably selected from Ru, Rh, Pt and Pd, advantageously platinum; and preferably is supported on a support selected from carbon supports.

5. A process according to any one of the preceding claims, wherein the metal hydrogenation / hydrogenolysis catalyst is supported, and has a dispersion of the metal on the support ranging from 1.2% to 90%, preferably from 2.0% to 75%, preferably from 2.5% to 50%, preferably from 3.0% to 20%, preferably from 3.0% to 15%, preferably from 3.5% to 12%, preferably between 3.8% and 10%.

6. A process according to any one of the preceding claims, wherein A) comprises the following steps: a) the preparation of a reaction medium heated to a temperature T1 greater than or equal to 90 °C and pressurized to a partial pressure PH2 of dihydrogen greater than or equal to 0.01 bar, the reaction medium comprising a metal hydrogenation / hydrogenolysis catalyst and optionally a solvent, and obtaining a heated and pressurized reaction medium, b) the introduction of the compound of formula (II) into the heated and pressurized reaction medium obtained in step a), optionally mixed with a solvent, and c) the formation of the mixture of compound of formula (I) and compound of formula (I').

7. A process according to any one of claims 1 to 5, wherein A) comprises the following steps: a') preparing a reaction medium heated to a temperature T1 greater than or equal to 90 °C and pressurized to a partial pressure PH2 of dihydrogen greater than or equal to 0.01 bar, the reaction medium comprising a solvent and the compound of formula (II), and obtaining a heated and pressurized reaction medium, b') introducing the metal hydrogenation / hydrogenolysis catalyst, optionally in solution or in suspension in a solvent, into the heated and pressurized reaction medium obtained in step a), and c') the formation of the mixture of compound of formula (I) and compound of formula (I').

8. A process according to claim 6 or 7, wherein the solvent is selected from C6-C20 alkanes, C1-C10 alcohols, and C3-C10 ketones, preferably from linear C6-20 alkanes, linear primary or secondary C3-C10 alcohols, preferably C3-C6, and linear C3-C10 alkanones, preferably C3-C6, or any mixture thereof; advantageously is dodecane, hexadecane, 2-hexanol, 2-hexanone, or a mixture of 2-hexanol and 2-hexanone or a mixture of 2-pentanol and 2-pentanone.

9. A process according to any one of the preceding claims, wherein the metal hydrogenation / hydrogenolysis catalyst is supported, and has a dispersion of the metal on the support ranging from 2.0% to 9.0%, preferably from 2.5% to 8.0%, preferably from 3.0% to 7.0%, preferably between 3.5% and 6.0%, preferably between 4.0% and 5.0%.

10. A method according to any one of the preceding claims, wherein the partial pressure of dihydrogen is maintained constant at the value (P H 2) during the implementation of the process, in particular during step ii), or c) or c').

11. A process according to any one of the preceding claims, wherein step d) is carried out in the presence of a metallic hydrogenation catalyst having a higher catalytic power for the hydrogenation of a C=O bond than that of the metallic hydrogenation / hydrogenolysis catalyst of step i) or a) or b'), preferably comprising ruthenium.

12. A method according to any one of the preceding claims, wherein step d) is carried out at a temperature T2 between 40°C and 150°C, preferably between 60°C and 120°C, preferably between 70°C and 90°C.

13. A process according to any one of claims 1 to 8, wherein the metal hydrogenation / hydrogenolysis catalyst is supported, and has a dispersion of the metal on the support ranging from 4.0% to 40%, preferably from 6.0% to 20%, preferably from 7.0% to 15%, preferably between 8.0% and 12%, preferably between 9.0% and 10%.

14. A method according to any one of claims 1 to 8 or 13, wherein the temperature T1 ranges from 190°C to 220°C, preferably from 190°C to 210°C.

15. A process according to any one of the preceding claims, further comprising a step e) of converting the compound of formula (I) from step d) into hydrocarbon(s), preferably C9-C20, preferably C9-C18, preferably C12-C18, said step e) comprising a substep e1) of oligomerization and a substep e2) of hydrogenation, step e1) being carried out before or after step e2).

16. A process for producing jet fuel, in particular renewable jet fuel, comprising at least one hydrocarbon, preferably C9-C20, preferably C9-C18, preferably C12-C18, said process comprising: A) steps i) and ii) according to any one of claims 1 to 5, 9 and 10, or steps a), b) and c) according to any one of claims 6, 9 and 10, or steps a'), b') and c') according to any one of claims 7 to 10, step ii), c) or c') forming a mixture of compound of formula (I) and compound of formula (I'); B) a step d) of hydrogenating the compound of formula (I') present in the mixture obtained from step ii) or c) or c'), said step being according to any one of claims 1, 11 and 12, to obtain a hydrogenated mixture; and C) a step e) of converting the hydrogenated mixture from step d) into hydrocarbon(s), preferably C9-C20, preferably C9-C18, preferably C12-C18, according to claim 15, and optionally D) a step of fractionating the converted mixture from C), to obtain the jet fuel.

Images