Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/40—Catalysts, in general, characterised by their form or physical properties characterised by dimensions, e.g. grain size
  • B01J35/45—Nanoparticles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
  • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
  • B01J21/063—Titanium; Oxides or hydroxides thereof
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/72—Copper
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
  • B01J35/39—Photocatalytic properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
  • B01J35/61—Surface area
  • B01J35/613—10-100 m2/g
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/0201—Impregnation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/34—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation
  • B01J37/349—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation making use of flames, plasmas or lasers
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C1/00—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon
  • C07C1/20—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon starting from organic compounds containing only oxygen atoms as heteroatoms
  • C07C1/207—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon starting from organic compounds containing only oxygen atoms as heteroatoms from carbonyl compounds
  • C07C1/2078—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon starting from organic compounds containing only oxygen atoms as heteroatoms from carbonyl compounds by a transformation in which at least one -C(=O)-O- moiety is eliminated
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C11/00—Aliphatic unsaturated hydrocarbons
  • C07C11/02—Alkenes
  • C07C11/04—Ethene
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2/00—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms
  • C07C2/02—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons
  • C07C2/04—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons by oligomerisation of well-defined unsaturated hydrocarbons without ring formation
  • C07C2/06—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons by oligomerisation of well-defined unsaturated hydrocarbons without ring formation of alkenes, i.e. acyclic hydrocarbons having only one carbon-to-carbon double bond
  • C07C2/08—Catalytic processes
  • C07C2/24—Catalytic processes with metals

Definitions

• the present invention relates to the use of TiO 2 particles carrying a metal and/or a metal oxide for obtaining alkenes by photocatalysis.
• the present invention also relates to a process for obtaining alkenes by photocatalysis of carboxylic acids and/or alcohols in the presence of a catalyst based on TiO 2 particles carrying a metal and/or a metal oxide.
• the at least one alkene is ethylene.
• step (i) is carried out in the absence of a continuous flow of inert gas. In this case, it is a mode that can be described as static. Still in this case, step (i) is carried out under an inert gas atmosphere. In particular, a purge as defined above is carried out prior to step (i). This purge is then stopped before carrying out step (i).
• the at least one carboxylic acid and/or the at least one alcohol is present within a composition further comprising a solvent, in particular in solution in a solvent, the solvent preferably being water, the concentration of alcohol(s) and/or carboxylic acid(s) in the composition being in particular greater than or equal to 0.0001% by volume, in particular greater than or equal to 0.01% by volume, and/or less than 100% by volume, for example approximately 1.00% by volume.
• the at least one carboxylic acid and/or the at least one alcohol is not in the presence of a solvent.
• the catalyst is present in the composition comprising the at least one carboxylic acid and/or the at least one alcohol and the solvent, or, in the absence of solvent, in the at least one carboxylic acid and /or at least one alcohol, at a concentration of 0.01 to 50 g/L, for example approximately 0.5 g/L.
• step (i) is carried out at a temperature between 10 and 200°C, in particular at a temperature between approximately 20 and approximately 40°C, or at a temperature between 40 and 40°C. 200°C, in particular from 40 to 150°C, or even from 40 to 100°C.
• step (i) is carried out at a temperature of 60 to 200°C, in particular at a temperature of 60 to 150°C, in particular of 60 to 100°C.
• the irradiation is UV-A, UV-B, UV-C, and/or visible irradiation, in particular UV-A, in particular at a wavelength of 350 to 400 nm.
• the invention relates to a process comprising a step (ii), following step (i), of recovering the alkene(s), this step (ii) being optionally followed by a step (iii) isolation of the alkene(s).
• Step (ii) can be carried out by any technique known to those skilled in the art, in particular by recovery of the headspace of the photocatalytic device used.
• Step (iii) can be carried out by any technique known to those skilled in the art, in particular by distillation, in particular by cryogenic distillation.
• This purification technique based on the fact that each gas has its own boiling temperature, consists of separating a gas mixture by varying the pressure and temperature of the gas storage medium.
• the gas mixture is first cooled to low temperature (usually T ⁇ -50°C).
• the gases are liquefied and then sent to a distillation column.
• the liquid is gradually heated, which allows the gases to be separated according to their boiling temperature.
• Step (iii) can also be carried out by absorption-based techniques.
• the separation is based on the principle that each gas has a particular affinity towards absorbents such as zeolites, alumina or activated carbon, or towards solvents such as methanolamine (MEA).
• the Pressure Swing Absorption (PSA) method best illustrates this technique. Separation occurs when the gas mixture comes into contact with the absorbent/solvent in a tank which is subsequently pressurized. The gas with the best affinity for the absorbent is trapped while the other gas species pass through the system. The reservoir is regenerated by returning to atmospheric pressure, releasing the formerly trapped gas.
• Step (iii) can also be carried out by membrane separation, always on the principle of affinity of the gases with respect to a membrane, allowing the gases to infiltrate more or less quickly through the membrane.
• the membrane materials frequently encountered in the literature are varied, such as microporous organic polymers, zeolites and ceramic or metal-based materials.
• the molar selectivity for alkene, in particular for ethylene is greater than or equal to 40%, in particular greater than 45%, more particularly greater than 50%.
• acetone and/or ethyl acetate is not formed at the end of the process.
• percentages refer to percentages by mass relative to the total mass of the formulation, unless otherwise indicated.
• value ranges in the form of "x-y” or “from x to y” or “between x and y” include the limits x and y as well as the integers between these limits.
• “1-5”, or “from 1 to 5" or “between 1 and 5" designate the integers 1, 2, 3, 4 and 5.
• the preferred embodiments include each integer taken individually in the value range, as well as any subcombination of these integers.
• preferred values for "1-5" may include the integers 1, 2, 3, 4, 5, 1-2, 1-3, 1-4, 1-5, 2-3, 2 -4, 2-5, etc.
• alkyl refers to a straight or branched chain alkyl group having the number of carbon atoms indicated before said term, in particular 2 to 6 carbon atoms, such as ethyl, propyl, isopropyl , butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isoamyl, neopentyl, 1-ethylpropyl, 3-methylpentyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, hexyl, etc.
• C1-C4 alkyl designates an alkyl radical containing 1 to 4 carbon atoms. The same is true for the term “alkane.”
• Cycloalkyls are in particular alkyls (as defined above) comprising a ring. This is, for example, cyclohexyl.
• arene refers to a mono- or bicyclic, substituted or unsubstituted, aromatic hydrocarbon ring system having 6 to 10 ring carbon atoms. Examples include benzene and naphthalene. Preferred arenes include unsubstituted or substituted benzene and naphthalene. Included in the definition of "arene” are fused ring systems, including, for example, ring systems in which an aromatic ring is fused to a cycloalkyl ring. Examples of such condensed ring systems include, for example, indane, indene and tetrahydronaphthalene.
• GC Gas chromatography
• FID flame ionization detector
• PHID helium ionization detector
• Example 1 Example of a photocatalytic device allowing the implementation of a use or a process according to the invention
• the photocatalytic device ( ) is composed of an airtight Pyrex reactor with a volume of 250 mL comprising 100 mL of aqueous solution, 150 mL of headspace, a glass mechanical stirrer as well as a bubbler (also made of glass ) ensuring a neutral gas supply.
• the neutral gas can be helium He, nitrogen N 2 or preferably argon Ar.
• An 18W Phillips UVA PLL lamp delivering a power flux density of 4.8 mW.cm -2, was used as a light source centered at 370 nm.
• the emitted wavelengths were between 350 and 400 nm.
• the concentration of alcohol(s) or carboxylic acid(s) in the solution is between 0.01 and 100% by volume, preferably 1.00%.
• the alcohol and/or carboxylic acid compounds may or may not be introduced in the form of a mixture.
• the concentration of metal (oxide) photocatalyst/TiO 2 is between 0.01 and 50 g/L, preferably 0.5 g/L.
• the aqueous suspension comprising one or more alcohol(s) and/or one or more carboxylic acid(s) and the photocatalyst is irradiated by UVA.
• the photocatalytic reaction can be carried out under a continuous flow of neutral gas (dynamic mode) or statically (without neutral gas flow), preferably statically.
• the neutral gas flow during purging and/or under irradiation is between 1 and 500 mL/min, preferably 50 and 70 mL/min.
• the gases produced in the reactor headspace during photocatalysis are analyzed by gas chromatography via a flame ionization detector (FID) and a helium plasma detector (PDHID).
• FID flame ionization detector
• PDHID helium plasma detector
• the gases are carried by the neutral gas flow; in the static mode case, the gases are transported by pumping.
• Example 2 preparation of a catalyst allowing the implementation of a use or a process according to the invention
• the metal and/or metal oxide can be brought into contact with the surface of the TiO 2 particles by any technique known to those skilled in the art. It may for example be a laser pyrolysis or impregnation technique.
• TiO 2 (non-invention) and metal (oxide)/TiO 2 photocatalysts of the invention can be synthesized by the laser pyrolysis technique, an example of which is given below with copper as metal.
• a liquid mixture comprising the titanium and copper precursors is inserted into an enclosure called a “pyrosol” comprising a cooling device, a drive gas inlet and a piezoelectric pellet.
• the titanium precursor is titanium isopropylate (TTIP);
• the copper precursor can for example be copper acetylacetonate Cu(acac) 2 .
• the copper precursor can be dissolved beforehand in one or more organic solvent(s) such as a mixture of o-xylene/ethyl acetate in a proportion of 6.5:3.5 in volume.
• the constitution of said mixture is indicated in Table 1 below for a targeted copper content of 2.00 wt% relative to the mass of TiO 2 .
• the liquid mixture of precursors is converted into an aerosol by actuation of the piezoelectric pellet.
• the mixture can be heated throughout the synthesis, over a range from 10 to 100°C.
• the mixture is heated to 30°C.
• the aerosol obtained is then conveyed into a reaction chamber confined under a neutral atmosphere via a carrier gas which can be helium He, argon Ar or even nitrogen N 2 .
• the confinement gas in the reaction chamber can be helium He, argon Ar or even nitrogen N 2 .
• the drive and confinement gases (chimney, reactor windows) are argon Ar.
• the confinement flow rates are between 0 and 5000 cm 3 .min -1 , preferably 0 cm 3 .min -1 for confinement at the level of the chimney and 3,000 cm 3 .min -1 for confinement at the level of the visibility windows.
• the flow rate of entrainment gas is between 50 and 10,000 cm 3 .min -1 , preferably 2,000 cm 3 .min -1 .
• a CO 2 infrared laser beam with a wavelength of 10.6 ⁇ m and a power of up to 2,800 W is emitted orthogonally to the mixture of precursors, conveyed in the form of fine droplets.
• the laser power delivered in the reaction zone is between 100 and 900 W and of the order of 670 W for the synthesis of TiO 2 and Cu/TiO 2 .
• a gas absorbing laser radiation preferably ethylene C 2 H 4 , can also be added in a flow rate range from 0 to 5,000 cm 3 .min -1 . In the present example, the flow rate of this gas is set at 800 cm 3 .min -1 .
• the laser power absorbed by the aerosol of precursors shown in Table 1 is 276 W for TiO 2 , and 250 W for Cu/TiO 2 .
• the interaction between the laser beam, the aerosol of precursors and possibly the ethylene gas allows the growth of nanoparticles collected on the surface of a filter barrier comprising nanopores. Note that the use of ethylene for the synthesis is optional and that it is possible to synthesize TiO 2 and Cu/TiO 2 materials without using it.
• the nano-powders synthesized by said process are then calcined in a tubular furnace via an air reactor to remove the amorphous carbon coming from the precursors and possibly ethylene gas if ethylene is used.
• the heat treatment applied is for example a temperature of 450°C under air flow at 100 mL.min -1 for a duration ranging from 3 to 6 hours - until almost total or even total elimination of the amorphous carbon, here, for example 6 hours.
• the copper content in the Cu/TiO 2 material synthesized by laser pyrolysis is 1.91% by mass which is very similar to the percentage introduced in pyrosol (2.00% by mass).
• TEM transmission electron microscopy
• the metal (oxide)/TiO 2 photocatalysts of the invention can also be synthesized by impregnation of metal via a metal precursor on a TiO 2 support.
• This TiO 2 support can be commercial or obtained by laser pyrolysis, for example the TiO 2 described above. An example is given below with copper as the metal.
• the metal precursor in the case of copper, is not limited to this compound and can be for example copper acetate (anhydrous or hydrated) or even copper nitrate.
• one or more organic solvents such as ethanol can be added and the precursors are dispersed in an ultrasonic bath. Once the precursors have completely dissolved, the mixture is transferred to a 50 mL flat-bottomed flask and heated in a water bath to 70°C. The stirred mixture is evaporated via a magnetic bar over a period of 12 hours and the residual powder is dried in an oven at 120°C.
• the impregnated powder is then calcined at 450°C for 6 hours in a reactor in a tubular furnace under an air flow at 100 mL.min -1 .
• the copper content in the Cu/TiO 2 material synthesized by impregnation is 2.15%m which is very similar to the percentage (2.00 %m) introduced into a flask for impregnation of the TiO 2 support.
• the photocatalysts TiO 2 (reference outside the invention) and Cu/TiO 2 (example 2, first part) were introduced into the pre-mentioned photocatalytic reactor ( ) at a level of 0.5 gL -1 with 1 vol% of propanoic acid in 100 mL of aqueous solution.
• An argon flow set at 70 mL/min for 6 hours made it possible to expel the air from the photocatalytic reactor and replace it with a neutral argon atmosphere. After complete purging, the flow of argon is stopped and the photocatalytic reactor is isolated.
• the photo-produced gaseous compounds were sampled from the reactor headspace to be sent to the GC/FID and GC/PDHID.
• Table 4 indicates the hourly gas productions obtained for this reaction as well as the selectivities, calculated according to the quotient [compound]/ ⁇ [C x H y O z ] with x and y ⁇ 1 after 910 minutes of irradiation .
• the yield of ethylene calculated by the ratio [C 2 H 4 /CO 2 ] considering that a photo-degraded propanoic acid molecule forms an ethane radical and a CO 2 molecule and that an ethane radical can form a molecule of ethylene or ethane, is 1.0% for TiO 2 and 85.0% for Cu/TiO 2 after 910 minutes of irradiation.
• the Cu IMP /TiO 2 impregnated photocatalyst was introduced into the pre-mentioned photocatalytic reactor ( ) at a level of 0.5 gL-1 with 1 vol% of propanoic acid in 100 mL of aqueous solution.
• the synthesis of ethylene by photocatalysis took place under the same conditions as described above.
• Table 5 indicates the hourly gas productions obtained for this reaction as well as the selectivities, calculated according to the quotient [compound]/ ⁇ [C x H y O z ] with x and y ⁇ 1 after 910 minutes of irradiation .
• the ethylene yield is 1.0% for TiO 2 and 86.5% for Cu IMP /TiO 2 after 910 minutes of irradiation.

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• 2022
  • 2022-06-03 FR FR2205384A patent/FR3136177B1/fr active Active
• 2023
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