Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C57/00—Unsaturated compounds having carboxyl groups bound to acyclic carbon atoms
  • C07C57/02—Unsaturated compounds having carboxyl groups bound to acyclic carbon atoms with only carbon-to-carbon double bonds as unsaturation
  • C07C57/03—Monocarboxylic acids
  • C07C57/04—Acrylic acid; Methacrylic acid
• • 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
  • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J23/24—Chromium, molybdenum or tungsten
  • B01J23/28—Molybdenum
• • 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
• • 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
  • B01J23/002—Mixed oxides other than spinels, e.g. perovskite
• • 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
  • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
  • B01J27/02—Sulfur, selenium or tellurium; Compounds thereof
  • B01J27/057—Selenium or tellurium; Compounds thereof
  • B01J27/0576—Tellurium; Compounds 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
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/19—Catalysts containing parts with different compositions
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
  • C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen
  • C07C51/215—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of saturated hydrocarbyl groups
• • 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
  • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J23/18—Arsenic, antimony or bismuth
• • 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
  • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J23/20—Vanadium, niobium or tantalum
• • 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
  • B01J2523/00—Constitutive chemical elements of heterogeneous catalysts

Definitions

• the present invention relates to the selective oxidation of propane to acrylic acid, by using catalysts in a mixture of crystalline phases, as well as the preparation of these catalysts.
• Patent application JP 10-330343 describes catalysts useful for the preparation of nitriles by oxidation of an alkane in the gas phase. These crystal structure catalysts are represented by the formula Mo a VbSb c X x O n and defined by their lattice parameters and the diffraction angles (2 ⁇ ). The symbol X represents one or more metallic elements chosen in particular from Ti, Zr, b, Ta, Cr, W, Sn, etc.
• These catalysts are prepared by adding solutions or suspensions containing respectively a source of antimony and a source of vanadium, then addition of a solution or suspension containing a specific quantity of molybdenum and addition of element X in the form of powder or solution.
• the oxides of these elements or of derivatives such as ammonium metavanadate or ammonium paramolybdate are particularly indicated.
• the method leads to a precursor which is dried and calcined to give a compound of metal oxides.
• Two phases can be obtained during preparation: a phase with an orthorhombic mesh and a phase with a hexagonal mesh.
• the orthorhombic mesh phase being the expected phase.
• the catalytic performances can be improved by "successive treatments of washing of the catalyst mixture obtained which make it possible to obtain the orthorhombic phase alone.
• Patent application JP 7-232071 describes catalysts with a crystalline structure corresponding to a formula of the MoVTeX type. These catalysts are precalcined at 300 ° C. The X-ray diffraction lines indicated suggest the presence of an orthorhombic mesh structure.
• European patent application EP-A-608838 describes the preparation of an unsaturated carboxylic acid from an alkane according to a catalytic oxidation reaction in the vapor phase in the presence of a catalyst containing a mixed metal oxide comprising as essential components , Mo, V, Te, O, as well as at least one element chosen from the group consisting of niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, antimony, bismuth, boron, indium and cerium, these elements being present in very precise proportions.
• European patent application EP-A-895809 and US patent 6,143,916 describe catalysts based on oxides comprising molybdenum, vanadium, niobium, oxygen, tellurium and / or antimony. These catalysts are used for the conversion of propane to acrylic acid, in the presence of molecular oxygen (examples 9 and 10 of European application).
• Example 9 describes the oxidation of propane using a catalyst of formula Mo 1 V 0 (33 Nbo, ⁇ Te 0) 22 O n from a gas stream composed of propane, oxygen and helium and a stream of water vapor.
• US Patent 6,143,916 describes crystalline forms of these catalysts.
• phase A a crystalline phase of catalyst based on tellurium or antimony and molybdenum, preferably of hexagonal mesh (hereinafter called phase A), conferring selectivity on the final mixture, in association with a crystalline phase of A catalyst capable of activating propane can give completely unexpected oxidation results from the viewpoint of activity and selectivity. A synergistic effect can be observed when using the mixture of these crystalline catalytic phases.
• the tellurium or antimony and molybdenum-based phase which confers selectivity on the final mixture, can advantageously be chosen from tellurium and / or molybdenum compounds or antimony and molybdenum compounds with a hexagonal crystal structure (phase A), or from Te 2 MoO 7 , or Te 0 , 2 MoO x .
• the crystalline catalyst phase intended to confer good selectivity either corresponds to the formula:
• the crystalline catalyst phase capable of activating propane is a phase of crystallized metallic mixed oxides, more particularly based on molybdenum and vanadium such as mixed molybdenum and vanadium oxides, such as a hexagonal phase (phase A) antimony and niobium, or an orthorhombic phase catalyst (hereinafter called phase B).
• phase A hexagonal phase
• phase B orthorhombic phase catalyst
• the combination of the crystalline phases of catalyst is carried out at a rate of 90/10 to 15/85 by weight relative to the total mixture, of the catalyst conferring a good selectivity / catalyst capable of activating propane.
• the catalyst conferring good selectivity / catalyst capable of activating propane Preferably from 90/10 to 50/50 by weight relative to the total mixture, and in a very particularly preferred manner from 70/30 to 50/50 by weight relative to the total mixture, of the catalyst conferring good selectivity / catalyst capable of activating propane.
• the subject of the present invention is a process for the preparation of acrylic acid from propane, in which a gaseous mixture comprising propane, steam, optionally an inert gas and / or oxygen is passed through.
• a gaseous mixture comprising propane, steam, optionally an inert gas and / or oxygen is passed through.
• the method according to the present invention consists in passing the above-mentioned gas mixture over a catalyst consisting of a combination of a catalyst of formula (I), (P), Te 2 MoO 7 or Te 0; 2 MoO x and of a crystalline catalyst phase of formula (D), (IT) or (II ").
• the preparation of acrylic acid from propane is carried out using a catalyst consisting of a combination of phases crystalline at a rate of 90/10 to 15/85 by weight relative to the total mixture, of the catalyst conferring good selectivity / catalyst capable of activating propane.
• a catalyst consisting of a combination of phases crystalline at a rate of 90/10 to 15/85 by weight relative to the total mixture, of the catalyst conferring good selectivity / catalyst capable of activating propane.
• a rate of 90/10 to 50/50 by weight and in a particularly preferred manner at a rate of 70/30 to 50/50 by weight relative to the total mixture, of the catalyst conferring good selectivity / catalyst capable of activating propane.
• the propane / molecular oxygen molar ratio in the starting gas mixture is greater than or equal to 0.5.
• a molecular ratio greater than or equal to 0.3 may also be advantageous.
• the present invention also relates to the use of a crystal structure of catalyst combination of formula (I) or (F), Te 2 MoO 7 or Te 0, 2 MoO x with crystalline structure of catalysts of formula (II), (IF) or (II ") capable of activating propane, for the preparation of acrylic acid from propane.
• the method according to the invention makes it possible to simultaneously obtain good selectivity for acrylic acid and significant conversion of propane.
• it can be easily implemented in a fixed bed, in a fluidized bed or in a transported bed and the injection of the reagents can be carried out at different points of the reactor, so that one is outside the zone of flammability while having a high propane concentration and, therefore, a high catalyst productivity. Unconverted propane can be recycled.
• the method according to the invention comprises the following steps:
• the process comprises repeating, in a reactor provided with the combination of catalysts, the cycle comprising the following successive stages:
• step 1) can be carried out in the form of multiple injections.
• the cycle comprises an additional stage which precedes or follows stage 1) and during which a gaseous mixture corresponding to that of stage 1 is injected but without molecular oxygen, the propane / molecular oxygen molar ratio then being calculated globally for step 1) and this additional step.
• the additional step precedes step 1) in the cycle.
• the propane / molecular oxygen molar ratio in the starting gas mixture is preferably greater than or equal to 0.5 or greater than or equal to 0.3
• the conversion of propane to acrylic acid by means of the catalyst is carried out by oxidation, probably according to the following concurrent reactions (A) and (B): - the conventional catalytic reaction (B ):
• the propane / water volume ratio in the starting gas mixture is not critical and can vary within wide limits.
• the proportion of inert gas which can be helium, krypton, a mixture of these two gases, or nitrogen, carbon dioxide, etc., is also not critical and may also vary within wide limits.
• reactions (A) and (B) are carried out at a temperature of 200 to 500 ° C, preferably 250 to 450 ° C, more preferably still, 350 to 400 ° C.
• the pressure in the reactor (s) is generally from 1.01.10 4 to 1.01.10 ° Pa (0.1 to 10 atmospheres), preferably from 5.05.10 4 to 5.05.10 5 Pa (0.5- 5 atmospheres).
• the residence time in the reactor is generally from 0.01 to 90 seconds, preferably from 0.1 to 30 seconds.
• crystallized catalysts of formulas (I), (F), Te 2 MoO 7 or Teo, 2 MoO x or of formulas (II), (II ') and (II ") can be prepared according to various processes such as by hydrothermal synthesis , by co-precipitation or by solid-solid reaction.
• the sources of the different metals used as raw materials are often oxides, but are not limited to oxides.
• molybdenum in the case of molybdenum, ammonium molybdate, ammonium paramolybdate, ammonium hepta-molybdate, molybdic acid, molybdenum halides or oxyhalides such as M0CI 5 , the compounds organometallic molybdenum such as molybdenum alkoxides such as
• Mo (OC 2 H 5 ) 5 molybdenyl acetylacetone; "in the case of tellurium, tellurium, telluric acid, TeO 2 ;
• antimony for example antimony oxide (antimony trioxide), in particular the variety Senarmontite, antimony sulfate
• One method of preparing the catalysts consists in mixing, with stirring, aqueous solutions of niobic acid, oxalic acid, ammonium heptamolybdate, ammonium metavanadate, telluric acid or antimony oxide, then preferably precalcine in air at around 300-320 ° C, and calcine under nitrogen at about 600 ° C.
• a process for preparing the catalysts consists in implementing the preparation of a solution of niobic acid and oxalic acid, the preparation of a solution of molybdenum, vanadium, tellurium or antimony , mixing of the 2 solutions giving rise to the formation of a gel, then drying of the gel obtained, precalcination and calcination.
• the catalyst can be prepared by implementing the following steps:
• the drying [for example of step 8)] can be carried out in an oven in a thin layer, by atomization, by lyophilization, by zeodratation, by microwave, etc .;
• the precalcination can be carried out under air flow at 280-300 ° C or under static air at 320 ° C, in a fluidized bed, in an oven rotating in a fixed so-called aerated bed, so that the catalyst grains are separated each other to prevent them from fusing during precalcination or possibly during calcination;
• the calcination is preferably carried out under very pure nitrogen and at a temperature in the region of 600 ° C., for example in a rotary kiln or in a fluidized bed and for a period which may be 2 hours.
• the precalcination is carried out:
• the precalcination is carried out: - at around 320 ° C under an air flow rate of less than 10 ml / min / g; or
• a solid-solid reaction is carried out by mixing the metal sources and then co-grinding until a homogeneous mixture is obtained.
• the solid is obtained after heating under reduced pressure at a temperature in the region of 600 ° C.
• the metal oxides or the metal itself are used as the source of metals. More preferably, the heating is carried out for an extended time (preferably 3 days to 1 week).
• the catalysts prepared according to the methods described above can each be in the form of grains generally from 20 to 300 ⁇ m in diameter, the grains of each of the associated catalysts being generally mixed before the implementation of the method according to the invention.
• the shaping can be carried out by spraying a gel or a suspension.
• the combination of catalysts can also be in the form of a solid catalytic composition composed of grains, each of which comprises both of the catalysts.
• the proportions of the constituents of the regeneration gas mixture are generally as follows (in molar ratios): oxygen / inert (He-Kr) / H 2 O (vapor) ⁇ 1 / 1-10 / 0-10,
• they are 1 / 1-5 / 0-5.
• the regeneration temperature is generally 250 to 500 ° C.
• the process is generally carried out until the reduction rate of the catalyst is between 0.1 and 10 g of oxygen per kg of catalyst. This reduction rate can be monitored during the reaction by the quantity of products obtained. The equivalent amount of oxygen is then calculated. It can also be followed by the exothermicity of the reaction. We can also follow the reduction rate by the amount of oxygen consumed in the regenerator.
• the regeneration which can be carried out under conditions of temperature and pressure identical to, or different from those of reactions (A) and (B), the catalysts regain initial activity and can be reintroduced into the reactors.
• Reactions (A) and (B) and regeneration (C) can be carried out in a conventional reactor, such as a fixed bed reactor, a fluidized bed reactor or a transported bed reactor.
• Reactions (A) and (B) and regeneration (C) can also be carried out in the same reactor by alternating the reaction and regeneration periods.
• the reactions (A) and (B) and the regeneration (C) are carried out in a reactor with a transported catalyst bed, in particular in a vertical reactor, the catalyst then preferably moving from the bottom to the top.
• the propylene produced and / or the unreacted propane are recycled (or returned) at the inlet of the reactor, that is to say that they are reintroduced at the inlet of the reactor, in mixture or in parallel with the starting mixture of propane, water vapor and, where appropriate, inert gas (ies).
• the present invention has the great advantage of combining very good selectivity for acrylic acid and good conversion of propane, due to the combination of the catalysts used and the synergistic effect provided.
• synergistic effect it can be seen, on the one hand, that each catalyst taken separately is less efficient than the combination of the catalyst capable of providing good selectivity with the catalyst capable of activating propane and, on the other hand, the selectivity observed is greater than the additive effect provided by the 2 catalysts taken in isolation, in almost all cases. This effect can be observed in particular in the tests which follow.
• the preparation is carried out by solid-solid reaction in a vacuum-sealed ampoule. 10.00 g of MoO 3 (Merck), 1.37 g of molybdenum metal (Alfa Aesar), 8.01 g TeO 2 (Alfa Aesar) and 3.04 g VO 5 (Riedel de Ha ⁇ n) are co-ground in a mortar agate for 15 minutes, until a homogeneous mixture is obtained. This mixture is introduced into a quartz bulb. The ampoule is then sealed under vacuum and heated to 600 ° C for one week. The solid recovered is analyzed by X-ray diffraction.
• the analysis confirms that the desired phase has been obtained, which corresponds to the hexagonal structure (diffractogram - Figure 1).
• the solid obtained has the chemical formula: MoV 0; 8 Teo, 6 ⁇ x , x being the quantity of oxygen corresponding to the oxidation state of the cations.
• phase A with tellurium and niobium of composition MoVp ⁇ Tep ⁇ Nbn iO x .
• the tellurium phase A containing niobium_a was obtained by co-precipitation.
• 5.00 g of ammonium heptamolybdate (Starck)) + 1.00 g of ammonium metavanadate (GFE) + 2.60 g of telluric acid (Fluka) + 25 ml of water are introduced into a beaker.
• the mixture is heated (70 ° C.) with stirring until a clear solution is obtained.
• 0.52 g of niobic acid (CBMM) + are introduced into a beaker.
• the mixture is heated until the solution clears (approximately 4 hours, temperature 70 ° C.), it is centrifuged (350O revolutions / min for 15 minutes) then the liquid phase is added to the solution containing Mo, V and Te. An orange gel is then obtained which is placed overnight in an oven at 110 ° C.
• the solid obtained is pre-calcined in air for 4 hours at 300 ° C (50 ml / min / g) and calcined for 2 hours at 600 ° C under nitrogen (50 ml / min / g).
• the solid obtained has the chemical formula: MoVo , 3 Te 0) 4 Nb 0) 1 O x .
• the solid recovered is analyzed by X-ray diffraction ( Figure 2).
• Antimony phase A is prepared like that of Example 1, but with the following constituents.
• the antimony-containing phase A containing niobium was obtained by co-precipitation.
• 7.00 g of ammonium heptamolybdate (Starck) + 1.39 g of ammonium metavanadate (GfE) are introduced into a beaker, the mixture is heated (80 ° C.) with stirring until a clear solution.
• 1.17 g Sb O 3 (Alfa Aesar) is then added and the mixture is left to stir for 4 hours without switching off the heating.
• 2 ml of H 2 O at 30% wt Alfa Aesar diluted in 10 ml of water are introduced, the solution then becomes clear orange.
• niobic acid ( ⁇ BMM) + 1.34 g of oxalic acid (Alfa Aesar) + 15 ml of water are introduced into a beaker.
• the mixture is heated until the solution clears (about 4 hours, temperature 70 ° C.), centrifuged (3500 rpm for 15 minutes) then the liquid phase is added to the solution containing Mo, V and Sb.
• a yellow gel is then obtained which is placed overnight in an oven at 110 ° C.
• the solid obtained is pre-calcined in air for 4 hours at 300 ° C.
• the solid obtained has the chemical formula: MoVo ) 3 Sb 0) 1 Nb 0; ⁇ Ow
• the Vo phase, 5 Mo ⁇ ! 9 ⁇ 5 was prepared by hydrothermal synthesis. 2.00 g of ammonium heptamolybdate (Starck), 1.33 g of VOSO 4 (Alfa Aesar) and 0.07g of NH 4 OH (28% by weight NH 3 ) are introduced with 50 ml of water into a 100ml Teflon jar. The mixture is left for 72 hours at 175 ° C. in an autoclave. The solid is then filtered, washed with distilled water, dried in an oven at 110 ° C and calcined under nitrogen at 600 ° C for 2 hours (50 ml / min / g).
• the solid obtained has a chemical formula of the Mo t V t O v type .
• the solid recovered is analyzed by X-ray diffraction ( Figure 5), it complies with JCPDS sheet 77-0649 (Joint Committee of Powder Diffraction Spectroscopy). This phase has been described by LM Plyasova et al., Kinetica i Kataliz, 31 (6), 1430-1434 (1990).
• the Te 2 MoO 7 phase was prepared by co-precipitation.
• a minimum of water (15 ml) 6.50 g of telluric acid (Fluka) and 2.50 g of ammonium heptamolybdate (Stark) are dissolved.
• the mixture is heated (80 ° C.) with stirring and allowed to evaporate until a white paste is obtained which is left to dry overnight in an oven at 110 ° C.
• the solid obtained is calcined for 2 hours at 470 ° C in air (50 ml / min / g).
• the solid obtained has the chemical formula:
• the solid recovered is analyzed by X-ray diffraction ( Figure 6), it complies with the JCPDS 70-0047 sheet. This phase has been described by A. Kaddouri et al., J. Therm. Anal. Cal, 66, 63-78 (2001).
• MoVTeNb catalyst containing a high concentration in phase B Into a 100 ml beaker are simultaneously introduced: 35 ml of distilled water + 7.78 g of ammonium heptamolybdate (Starck) + 1.70 g of ammonium metavanadate
• a niobic acid / oxalic acid solution with an oxalate / Nb ratio of 2.70 is prepared.
• the following are introduced into a 50 ml beaker: 10 ml of distilled water ⁇ 0.82 g of niobic acid (CBMM) + 1.67 g of oxalic acid (Alfa Aesar).
• CBMM niobic acid
• Alfa Aesar 1.67 g of oxalic acid
• an orange opaque gel is obtained which is placed in a crystallizer to be dried overnight in an oven at 110 ° C.
• the solid is pre-calcined in air at 300 ° C for 4 hours (50 ml / min / g) and then calcined in purified nitrogen at 600 ° C for 2 hours (50 ml / min / g)).
• the solid recovered is analyzed by X-ray diffraction. This shows a mixture of the hexagonal phase and the desired orthorhombic phase.
• the solid obtained has the chemical formula: Mo î Vo. ⁇ Teo. î oNbo. ⁇ O z and has a diffracto gram similar to that described by JMM Millet et al., Appl. Catal., 232, 77-92 (2002).
• the solid obtained is washed in a hydrogen peroxide solution (Alfa Aesar) at 30% wt diluted 2 times, for 4 hours, at room temperature.
• the solution is filtered and the recovered solid dried in an oven (110 ° C) and then calcined for 2 hours under nitrogen at 600 ° C (50 ml / min / g).
• the solid recovered is analyzed by X-ray diffraction (Figure 7). The analysis confirms that the desired phase has been obtained, which corresponds to the orthorhombic structure as described in the publication above with a small amount of hexagonal phase.
• the solid obtained has the chemical formula: M ⁇ V 0 . 26 Te 0 . 10 Nb 0 . 14 O z .
• MoVSbNh catalyst containing a high concentration in phase B In a flask, 1.99 g of ammonium metavanadate (GfE) and 45 ml of distilled water are introduced. The mixture is heated to reflux at 95 ° C. with stirring until a clear solution is obtained, then added: 1.24 g of antimony trioxide (Alfa Aesar) + 10.00 g of ammonium heptamolybdate (Starck ). The heating is left for 1 hour and it is placed under an argon sweep. A solution containing 2 ml of water is introduced oxygenated (Alfa Aesar) at 30% wt per 10 ml of water. A clear orange solution is then obtained.
• GfE ammonium metavanadate
• Starck ammonium heptamolybdate
• Alfa Aesar oxalic acid
• CBMM niobic acid
• the solid recovered is analyzed by X-ray diffraction. This shows a mixture of the hexagonal phase and the desired orthorhombic phase.
• the solid obtained has the chemical formula: MoVo ⁇ Sbo ⁇ sNbo ⁇ O w .
• the TeMo 5 O 16 phase was obtained by solid-solid reaction in a vacuum-sealed ampoule.
• 1.32 g of molybdenum metal (Alfa Aesar) and 6.65 g TeO (Alfa Aesar) are co-ground in an agate mortar for 15 minutes, until obtained d '' a homogeneous mixture.
• This mixture is introduced into a quartz bulb.
• the ampoule is then vacuum sealed and heated to 600 ° C for 72 hours.
• the solid recovered is analyzed by X-ray diffraction ( Figure 9), it complies with JCPDS sheet 70-0451.
• the analysis confirms that the desired phase has been obtained, which corresponds to the monoclinic structure having the chemical formula: MoTe 0j O x .
• Example 10 MoVTeNb containing a lot of phase B.
• a niobic acid / oxalic acid solution with an Ox / Nb ratio of 2.70 is prepared.
• the following are introduced into a 50 ml beaker: 10 ml of distilled water + 0.82 g of niobic acid (CBMM) + 1.67 g of oxalic acid (Alfa Aesar).
• CBMM niobic acid
• Alfa Aesar oxalic acid
• the mixture is heated to 70 ° C. with stirring until the starting solution clears up (about 4 hours).
• This solution is centrifuged (3500 rpm for 15 minutes) and then the liquid phase is introduced into the clear red solution containing molybdenum, vanadium and tellurium.
• an orange opaque gel is obtained which is placed in a crystallizer to be dried overnight in an oven at 110 ° C.
• the solid is pre-calcined in air at 300 ° C for 4 hours (50 mL / min / g) and then calcined in purified nitrogen at 600 ° C for 2 hours (50 mL / min / g)).
• the solid recovered is analyzed by X-ray diffraction. This shows a mixture of the hexagonal phase and the desired orthorhombic phase.
• the solid obtained has a diffractogram similar to that described in the publication JMM Millet, H. Roussel, A. Pigamo, JL Dubois, JC Jumas, Appl. Catal 232 (2002) 77-92, figure lb.
• the solid obtained has the chemical formula: MoV 0 , 3 Te 0; 2 Nb 0 , ⁇ .
• the solid obtained is washed in a solution of hydrogen peroxide (Alfa Aesar) at 30% diluted 2 times for 4 hours at room temperature.
• a niobic acid / oxalic acid solution with an Ox / Nb ratio of 2.70 is prepared.
• the following are introduced into a 50 ml beaker: 10 ml of distilled water + 0.82 g of niobic acid (CBMM) + 1.67 g of oxalic acid (Alfa Aesar).
• CBMM niobic acid
• Alfa Aesar oxalic acid
• the mixture is heated to 70 ° C. with stirring until the starting solution clears up (about 4 hours).
• This solution is centrifuged (3500 rpm for 15 minutes) and then the liquid phase is introduced into the clear red solution containing molybdenum, vanadium and tellurium.
• an orange opaque gel is obtained which is placed in a crystallizer to be dried overnight in an oven at 110 ° C.
• the solid is pre-calcined in air at 300 ° C for 4 hours (50 mL / min / g) and then calcined in purified nitrogen at 600 ° C for 2 hours (50 mL / min / g)).
• the solid recovered is analyzed by X-ray diffraction. This shows a mixture of the hexagonal phase and the desired orthorhombic phase.
• the solid obtained has a diffractogram similar to that described in the publication JMM Millet, H. Roussel, A. Pigamo, JL Dubois, JC Jumas, Appl. Catal 232 (2002) 77-92, figure lb.
• the solid obtained has the chemical formula: MoV 0j3 Te 0; 2 Nbo, ⁇ .
• the solid obtained is washed in a solution of hydrogen peroxide (Alfa Aesar) at 30% diluted 2 times for 4 hours at room temperature.
• the solution is filtered and the recovered solid " dried in an oven (110 ° C.) and then calcined for 2 hours under nitrogen at 600 ° C. (50 ml / min / g).
• the recovered solid is analyzed by X-ray diffraction. L analysis confirms that the desired phase, which corresponds to the orthorhombic structure as described in the above publication, is obtained with a small amount of hexagonal phase.
• the solid obtained has the chemical formula: CATALYTIOUE TEST:
• the pure phases thus prepared are tested as follows: 0.5 to 1.5 g of solid are loaded into a straight reactor with a fixed bed in Pyrex and the temperature rise (2.5 ° C / min) is carried out under nitrogen. When the desired temperature is reached, the reaction mixture is started: total flow rate of 30 ml / min (5% C 3 H 8 , 5% Ne, 10% O 2 , 45% H 2 O and 35% N 2 (% molars)) and the reactor is allowed to stabilize for 30 minutes. A 25 ml flask containing 5 ml of water is placed at the outlet of the reactor in order to allow the condensation of the organic compounds. For each temperature, the condensation time is 2 hours. The non-condensable products are analyzed online by a Chrompack chromatograph and the liquid effluents are analyzed after reaction on another Chrompack chromatograph.
• EXAMPLE 13 To carry out the tests of catalysts 10 and 11: tests Al, A2, AAl, AA2 under the same conditions as tests I and J of catalyst 7, a mass of 0.5 g was used for the tests Al and AAl, and a mass of 0.47 g was used for tests A2 and AA2. The results obtained are collated in Table 2. The results indicate a very good reproducibility of the performance of the catalysts.
• Table 1 Table of mechanical mixtures of the phases (mass of each solid in the mixture): Mass of the column solid (sohde C) + Mass of the Hgne solid (solid L). The letter indicated in the table corresponds to the reference of the example of the test.
• Examples B, C and E to K a mass m (specified in the table) of the solids prepared in Examples 2 to 9 is loaded into the reactor as in Example D, and the catalyst test is carried out as in example D.
• Examples L to Y and Z two masses im and m 2 of two different solids are mixed in an agate mortar for 15 min to obtain a homogeneous mixture. The mixture thus formed is loaded into a reactor as in Example D, then the catalyst test is carried out as in Example

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Catalysts (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=33427473

Family Applications (1)

Country Status (7)

Families Citing this family (21)

Family Cites Families (6)

• 2003
  • 2003-05-27 FR FR0306414A patent/FR2855516B1/fr not_active Expired - Fee Related
• 2004
  • 2004-05-25 CN CNA2004800145734A patent/CN1795045A/zh active Pending
  • 2004-05-25 JP JP2006530376A patent/JP2007502319A/ja active Pending
  • 2004-05-25 KR KR1020057022486A patent/KR20060006971A/ko not_active Application Discontinuation
  • 2004-05-25 WO PCT/FR2004/001290 patent/WO2004105938A2/fr active Application Filing
  • 2004-05-25 EP EP04767168A patent/EP1631382A2/de not_active Withdrawn
  • 2004-05-25 US US10/558,023 patent/US7683213B2/en not_active Expired - Fee Related

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events