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
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/03—Precipitation; Co-precipitation
  • B01J37/031—Precipitation
• • 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
  • B01J21/02—Boron or aluminium; 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
  • B01J23/002—Mixed oxides other than spinels, e.g. perovskite
• • 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
  • C07C51/23—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of oxygen-containing groups to carboxyl groups
  • C07C51/235—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of oxygen-containing groups to carboxyl groups of —CHO groups or primary alcohol groups
• • 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
  • C07C51/25—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of unsaturated compounds containing no six-membered aromatic ring
  • C07C51/252—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of unsaturated compounds containing no six-membered aromatic ring of propene, butenes, acrolein or methacrolein
• • 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

• TITLE CATALYST FOR THE OXIDATION OF A MIXED ALDEHYDE
• the present invention relates to a heteropolyacid catalyst including at least molybdenum (Mo), phosphorus (P), vanadium (V), and a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof used in producing methacrylic acid by the gas-phase catalytic oxidation of an aldehyde or a mixture of aldehydes, and methods for making and using same.
• Mo molybdenum
• P phosphorus
• V vanadium
• a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof used in producing methacrylic acid by the gas-phase catalytic oxidation of an aldehyde or a mixture of aldehydes, and methods for making and using same.
• the present invention relates to a heteropolyacid catalyst including molybdenum (Mo), phosphorus (P), vanadium (V), and a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof, where the catalyst is adapted to produce methacrylic acid by the gas-phase catalytic oxidation of an aldehyde feedstock including isobutanal (isobutyraldehyde) or isobutanal and methacrolein mixtures.
• the catalyst can also include copper (Cu).
• the catalyst can also include a second component selected from the group consisting of potassium (K), rubidium (Rb), cesium (Cs), thallium (Tl), and mixtures or combinations thereof.
• the catalyst can also include a third component selected from the group consisting of antimony (Sb), cerium (Ce), niobium (Nb), indium (hi), iron (Fe), chromium (Cr), cobalt (Co), nickel (Ni), manganese (Mn), arsenic (As), silver (Ag), zinc (Zn), germanium (Ge), gallium (Ga), zirconium (Zr), magnesium (Mg), barium (Ba), lead (Pb), tin (Sn), titanium (Ti), aluminum (Al), silicon (Si), tantalum (Ta), tungsten (W), lanthanum (La), and mixtures or combinations thereof.
• the invention also relates to methods for making and using same.
• Isobutanal is an intermediate of a process for production of methacrylic acid from propylene. Isobutyraldehyde is formed from the reaction of propylene, carbon monoxide and hydrogen, then oxidation of isobutyraldehyde produces methacrylic acid. [0004] Isobutyraldehyde is also a by-product of 2-ethyl-hexanol production. In this process, propylene is hydroformylated to a mixture of n-butanal (n-butyraldehdye) and isobutanal
• IBA means isobutanal, sometimes also referred to as isobutyraldehyde.
• MAC methacrolein
• MAA means methacryclic acid.
• T means temperature
• P means pressure
• HC means hydrocarbon
• aldehyde feedstock means a stream including mixtures of isobutanal and methacrolein.
• GC gas chromatography
• FID flame ionization detector of a GC.
• h or hr or hrs means hours.
• mL means milliliter
• min or min. means minutes.
• wt% or wt.% means weight percent.
• vol% or vol.% means volume percent.
• DI water means deionized water.
• pore volume distribution means a desired concentration of small pores, medium pores and large pores.
• small pores means pores having a diameter D less than about 1 OO ⁇ , i. e. , D ⁇ 100A.
• medium pores means pores having a diameter D greater than or equal to about 100A and less than about 1000 A, i.e., IOOA ⁇ D ⁇ 1000 A.
• large pore volume means pores having a diameter D greater than or equal to about lOOOA, i.e., D ⁇ 1000 A.
• the present invention provides a novel, highly active, heteropolyacid catalyst including at least molybdenum (Mo), phosphorus (P), vanadium (V), and a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof, where the catalyst is capable of converting an aldehyde feedstock into methacrylic acid.
• Mo molybdenum
• P phosphorus
• V vanadium
• a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof where the catalyst is capable of converting an aldehyde feedstock into methacrylic acid.
• the present invention provides a novel, highly active, heteropolyacid catalyst including ' at least molybdenum (Mo), phosphorus (P), vanadium (V), and a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof, and a second component selected from the group consisting of potassium (K), rubidium (Rb), cesium (Cs), thallium (Tl), and mixtures or combinations thereof, where the catalyst is capable of converting an aldehyde feedstock into methacrylic acid.
• Mo molybdenum
• P phosphorus
• V vanadium
• a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof and a second component selected from the group consisting of potassium (K), rubidium (Rb), cesium (Cs), thallium (Tl), and mixtures or combinations thereof
• K potassium
• Rb rubidium
• Cs cesium
• the present invention provides a novel, highly active, heteropolyacid catalyst including at least molybdenum (Mo), phosphorus (P), vanadium (V), and a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof, a second component selected from the group consisting of potassium (K), rubidium (Rb), cesium (Cs), thallium (Tl), and mixtures or combinations thereof and a third component selected from the group consisting of antimony (Sb), cerium (Ce), niobium (Nb), indium (In), iron (Fe), chromium (Cr), cobalt (Co), nickel (Ni), manganese (Mn), arsenic (As), silver (Ag), zinc (Zn), germanium (Ge), gallium (Ga), zirconium (Zr), magnesium (Mg), barium (Ba), lead (Pb), tin (Sn), titanium (Ti), aluminum
• the present invention provides a novel, highly active, heteropolyacid catalyst including at least molybdenum (Mo), phosphorus (P), vanadium (V), copper (Cu) and a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof, where the catalyst is capable of converting an aldehyde feedstock into methacrylic acid.
• Mo molybdenum
• P phosphorus
• V vanadium
• Cu copper
• a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof where the catalyst is capable of converting an aldehyde feedstock into methacrylic acid.
• the present invention provides a novel, highly active, heteropolyacid catalyst including at least molybdenum (Mo), phosphorus (P), vanadium (V), copper (Cu), a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof and a second component selected from the group consisting of potassium (K), rubidium (Rb), cesium (Cs), thallium (Tl), and mixtures or combinations thereof, where the catalyst is capable of converting an aldehyde feedstock into methacrylic acid.
• Mo molybdenum
• P phosphorus
• V vanadium
• Cu copper
• a second component selected from the group consisting of potassium (K), rubidium (Rb), cesium (Cs), thallium (Tl), and mixtures or combinations thereof
• the present invention provides a novel, highly active, heteropolyacid catalyst including at least molybdenum (Mo), phosphorus (P), vanadium (V), copper (Cu), a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof and a third component selected from the group consisting of antimony (Sb), cerium (Ce), niobium (Nb), .
• Mo molybdenum
• P phosphorus
• V vanadium
• Cu copper
• a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof and a third component selected from the group consisting of antimony (Sb), cerium (Ce), niobium (Nb), .
• the present invention provides a novel, highly active, heteropolyacid catalyst including at least molybdenum (Mo), phosphorus (P), vanadium (V), copper (Cu), a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof, a second component selected from the group consisting of potassium (K), rubidium (Rb), cesium (Cs), thallium (Tl), and mixtures or combinations thereof and a third component selected from the group consisting of antimony (Sb), cerium (Ce), niobium (Nb), indium (In), iron (Fe), chromium (Cr), cobalt (Co), nickel (Ni), manganese (Mn), arsenic (As), silver (Ag), zinc (Zn), germanium (Ge), gallium (Ga), zirconium (Zr), magnesium (Mg), barium (Ba), lead (Pb), tin (Sn), titanium (T
• the present invention also provides a novel, highly active catalyst for converting an aldehyde feedstock into methacrylic acid, where the catalyst has the general formula:
• MI is selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof,
• Mil is selected from the group consisting of potassium (K), rubidium (Rb), cesium (Cs), thallium (Tl), and mixtures or combinations thereof,
• Mill is selected from the group consisting of antimony (Sb), cerium (Ce), niobium (Nb), indium (In), iron (Fe), chromium (Cr), cobalt (Co), nickel (Ni), manganese (Mn), arsenic
• a is a number having a value between about 0.1 and about 3.5
• b is a number having a value between about 0.01 and about 5.0
• c is a number having a value between about 0.0 and about 1.5
• d is a number having a value between about 0.01 and about 2.0 when MI is Bi, or a value between about 0.01 and about 5.0 when MI is B, and when MI is both Bi and B, then d includes between about 0.01 and about 2.0 of Bi and between about 0.01 and about 5.0 of
• e is a number having a value between about 0.0 and about 5.0
• f is a number having a value between about 0.0 and about 5.0
• g is a number having a value representing a sufficient number of oxygen atoms to balance the oxidation state of the catalyst of formula (I).
• the present invention also provides a novel, highly active catalyst for converting an aldehyde feedstock into methacrylic acid of the general formula:
• Mil is selected from the group consisting of potassium (K), rubidium (Rb), cesium (Cs), thallium (Tl), and mixtures or combinations thereof
• Mill is selected from the group consisting of antimony (Sb), cerium (Ce), niobium (Nb), indium (In), iron (Fe), chromium (Cr), cobalt (Co), nickel (Ni), manganese (Mn), arsenic (As), silver (Ag), zinc (Zn), germanium (Ge), gallium (Ga), zirconium (Zr), magnesium (Mg), barium (Ba), lead (Pb), tin (Sn), titanium (Ti), aluminum (Al), silicon (Si), tantalum (Ta), tungsten (W), lanthanum (La), and mixtures or combinations thereof, a is a number having a value between about 0.5 and about 3.5, b is a number having a value between about 0.01 and about 5.0, c is a
• the present invention also provides a novel, highly active catalyst for converting an aldehyde feedstock to methacrylic acid of the general formula:
• Mil is selected from the group consisting of potassium (K), rubidium (Rb), cesium (Cs), thallium (Tl), and mixtures or combinations thereof,
• Mill is selected from the group consisting of antimony (Sb), cerium (Ce), niobium (Nb), indium (In), iron (Fe), chromium (Cr), cobalt (Co), nickel (Ni), manganese (Mn), arsenic
• a is a number having a value between about 0.5 and about 3.5
• b is a number having a value between about 0.01 and about 5.0
• c is a number having a value between about 0.0 and about 1.5
• d2 is a number having a value between about 0.01 and about 5.0
• e is a number having a value between about 0.0 and about 5.0
• f is a number having a value between about 0.0 and about 5.0
• g is- a number having a value representing a sufficient number of oxygen atoms to balance the oxidation state of the catalyst of formula (III).
• the present invention also provides a novel, highly active catalyst for converting an aldehyde feedstock to methacrylic acid of the general formula:
• Mil is selected from the group consisting of potassium (K), rubidium (Rb), cesium (Cs), thallium (Tl), and mixtures or combinations thereof,
• Mill is selected from the group consisting of antimony (Sb), cerium (Ce), niobium (Nb), indium (In), iron (Fe), chromium (Cr), cobalt (Co), nickel (Ni), manganese (Mn), arsenic (As), silver (Ag), zinc (Zn), germanium (Ge), gallium (Ga), zirconium (Zr), magnesium (Mg), barium (Ba), lead (Pb), tin (Sn), titanium (Ti), aluminum (Al), silicon (Si), tantalum (Ta), tungsten (W), lanthanum (La), and mixtures or combinations thereof, a is a number having a value between about 0.5 and about 3.5, b is a number having a value between about 0.01 and about 5.0, c is a number having a value between about 0.0 and about 1.5, dl is a number having a value between about 0.01 and about 2.0, d2 is a number having a
• the present invention provides a method for preparing a novel, highly active catalyst for converting an aldehyde feedstock to methacrylic acid.
• the references to moles used in describing the preparation of the catalysts of this invention mean relative molar amounts, e.g., if 1 mole of catalyst is being prepared, the catalyst will have moles of components such that the molar ratio of molybdenum in the catalyst relative to the other components is 12.
• the number of moles of components used during catalyst preparation will be in a molar ratio of 12:a:b:c:dl:d2:e:f:g.
• the method includes the step of forming a first substantially solid free solution of 12 moles of Mo (1 mole OfMo 12 ), a moles of P and b moles of V. IfBi is present in the catalyst, then a second substantially solid-free solution containing dl moles of Bi is prepared and the two solutions are then mixed to form a slurry.
• the solution is heated to 95 0 C and d2 moles of B are added to the solution.
• the catalyst includes e moles of a second component selected from the group consisting of potassium (K), rubidium (Rb), cesium (Cs), thallium (Tl), and mixtures or combinations thereof, the e moles or any portion thereof of the second components can be added to the first solution prior to or after heating, to the second solution if Bi is present or to the resulting slurry prior to or after heating.
• the second component is cesium
• the cesium is added to the first solution.
• the e moles or any portion of the second components can also be added after the solution is precipitated or after the precipitate or slurry is dried, but prior to calcining.
• the catalyst also includes f moles of a third component selected from the group consisting of antimony (Sb), cerium (Ce), niobium (Nb), indium (In), iron (Fe), chromium (Cr), cobalt (Co), nickel (Ni), manganese (Mn), arsenic (As), silver (Ag), zinc (Zn), germanium (Ge), gallium (Ga), zirconium (Zr), magnesium (Mg), barium (Ba), lead (Pb), tin (Sn), titanium (Ti), aluminum (Al), silicon (Si), tantalum (Ta), tungsten (W), lanthanum (La), and mixtures or combinations thereof, then as with the e moles of the second components, the third components can be added in any portion as set forth above for the second components
• a desired amount of an ammonium-containing compound can be added to the first solution and/or the second solution.
• the ammonium-containing compound is then out-gassed under controlled conditions during catalyst calcination to achieve a desired pore size distribution, preferably a distribution high in medium pores.
• the second solution can include an amount of nitric acid to produce a nitric acid to Mo [2 ratio having a value between about 0.1 to 1.0 to greater than 6.0 to 1.0.
• the solution or slurry is then evaporated to form a dried pre-catalytic material, which is then calcined to form a catalyst of this invention.
• any portion of the second and third components can be added to the dried pre-catalyst material prior to calcining to form the catalyst of this invention.
• a mole ratio of the molybdenum-containing compound to the ammonium-containing compound (Mo:NH 4 ) is between about 0.0 to about 20.0 and between about 0.5 to about 20.0 for catalysts regardless of the molybdenum to nitric acid mole ratio.
• the mole ratio is between about 1.0 to about 15.0, and, particularly, the mole ratio is between about 2.0 to about 10.0.
• a mole ratio of the ammonium-containing compounds to nitric acid is between about 0.0 and about 2.0 and between about 0.1 and about 2.0 for catalysts regardless of the molybdenum to nitric acid mole ratio, preferably, between about 0.2 and about 1.8, particularly, between about 0.4 and about 1.6, and more particularly, between about 0.6 and about 1.4 and especially, between about 0.6 and about 1.2.
• the present invention also provides a method for preparing methacrylic acid including the step of contacting an aldehyde feedstock with a catalyst of this invention to form methacrylic acid, where the aldehyde feedstock comprises isobutanal or mixtures of isobutanal and methacrolein.
• a novel, highly active catalyst for the conversion of an aldehyde feedstock into methacrylic acid can be prepared including at least molybdenum (Mo), phosphorus (P), vanadium (V), and a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof.
• the catalyst is adapted to convert an aldehyde feedstock including isobutanal or mixtures of isobutanal and methacrolein into methacrylic acid.
• Such a catalyst is ideally suited for use in the conversion of feedstock derived from plants that produce methacrolein and/or produce isobutanal purposefully or as a by-product.
• the catalysts of this invention are ideally suited for use in facilities that have a source of methacrolein and isobutanal for the production of methacrylic acid.
• One such facility integrates a methacrylic acid production component and 2-ethyl-hexanol production component as set forth in co-filed and co- pending United States Patent Application having a Serial No. associated with Express Mail Label No. ER 441453545 US or any other facility that produces isobutanal as an unwanted by-product.
• the present invention broadly relates to novel, highly active, heteropolyacid catalysts including at least molybdenum (Mo), phosphorus (P), vanadium (V), and a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof, where the catalysts are capable of converting an aldehyde feedstock into methacrylic acid.
• Mo molybdenum
• P phosphorus
• V vanadium
• a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof where the catalysts are capable of converting an aldehyde feedstock into methacrylic acid.
• the present invention also broadly relates to a method for making such catalysts including the steps of forming a liquid phase including at least molybdenum (Mo), phosphorus (P), and vanadium (V), and a first component selected from the group consisting of bismuth (Bi), boron (B) and mixtures or combinations thereof, where the liquid phase can be aqueous, aqueous/organic mixtures, aqueous/non-aqueous mixtures, non-aqueous or organic.
• organic means a carbon containing solvent
• non-aqueous means a non-aqueous solvent that does not contain carbon.
• the mixture is then dried to form a pre-catalyst composition and then calcined to form a catalyst of this invention. If the catalyst does not include Bi, then the mixture is preferably a solid- free solution prior to initiating precipitation. If the catalyst includes Bi, then Bi is first dissolved to form a second solid-free solution, which is then added to the first solid-free solution of the other ingredients to form a slurry. If the catalyst also includes the second and/or third components, then these components can be added to the mixture, to either solution or to a dried material followed by further drying, but prior to calcining.
• the present invention also broadly relates to a process for making MAA including the step of contacting an aldehyde feedstock with a catalyst of this invention under catalysis conditions sufficient to convert a desired amount of the aldehydes in the aldehyde feedstock into MAA. Suitable Reagents
• Suitable compounds used for preparation of the catalysts of this invention include, without limitation, metal nitrates, metal carbonates, metal ammonium salts, metal halides, metal oxides, or mixtures or combinations thereof.
• Suitable molybdenum components include, without limitation, ammonium paramolybdate, molybdenum trioxide, molybdenum chloride, etc. or mixtures or combinations thereof.
• the preferred molybdenum component is ammonium paramolybdate.
• Suitable vanadium components include, without limitation, ammonium metavanadate, vanadium pentoxide, vanadium chloride, etc. or mixtures or combinations thereof.
• the preferred vanadium component is ammonium metavanadate.
• Suitable phosphorus components include, without limitation, phosphoric acid, ammonium phosphite, etc. or mixtures or combinations thereof.
• the preferred phosphorus component is phosphoric acid.
• Suitable copper components include, without limitation, copper nitrate, copper chloride, etc. or mixtures or combinations thereof.
• the preferred copper component is copper nitrate.
• Suitable bismuth components include, without limitation, bismuth nitrate, bismuth oxide, bismuth chloride, etc. or mixtures or combinations thereof.
• the preferred bismuth component is bismuth nitrate.
• Suitable Mil components include, without limitation, Mil nitrates, Mil oxides, Mil chlorides, etc. or mixtures or combinations thereof.
• the preferred Mil components are Mil nitrates and Mil oxides or mixtures or combinations thereof.
• Suitable Mill components include, without limitation, Mill nitrates, Mill oxides, Mill chlorides, etc. or mixtures or combinations thereof.
• the preferred Mill components are Mill nitrates and Mill oxides or mixtures or combinations thereof.
• Suitable ammonium-containing compounds for use in this invention include, without limitation, any ammonium compound that undergoes thermal decomposition to volatile components.
• ammonium-containing compounds include, without limitation, ammonium hydroxide, ammonium nitrate, ammonium chloride, ammonium bromide, ammonium carbonate, ammonium acetate, ammonium formate, ammonium propionate, ammonium butionate, other ammonium salts of carboxylic acids, or mixtures or combinations thereof.
• the catalysts of this invention are generally-prepared by initiating precipitation of a substantially precipitate free solution by means known in the art, e.g., heating and/or solvent evaporation, where the solution includes appropriate concentrations of desired catalytic components. While the solution preferably is substantially free of precipitates prior to initiating precipitation, the solution can include varying degrees of precipitates during the preparation procedure provided that the precipitates substantially dissolve prior to initiating precipitation.
• a slurry is formed when a substantially solid-free Bi solution is added to a substantially solid-free solution of other ingredients. Other ingredients can be added to the slurry or to the solid after drying followed by further drying, but prior to calcination.
• substantially solid-free means that the amount of precipitate present in the solution is less than 5 wt.%, preferably less than 2.5 wt.%, particularly less than 1 wt.% and especially less than 0.5 wt.%, with the ultimate goal being completely solid-free or precipitate-free.
• the present invention relates to improved catalysts for the oxidation of an aldehyde feedstock comprising isobutanal or isobutanal-methacrolein mixtures.
• the catalyst of this invention can be prepared from precursor solutions acidified with nitric acid in a nitric acid (HNO 3 ) to Mo 12 mole ratio of about 0.1 to greater than (>) about 6.0. That is, the catalyst can be made from solutions including about 0.1 moles of nitric acid per mole OfMo 12 to greater than about 6.0 moles nitric acid per mole Of Mo 12 .
• the solutions also include a sufficient amount of an ammonium- containing compound such as ammonium hydroxide to adjust the pH to a desired level and to increase a concentration of medium pores in the final catalyst to a relatively high value.
• an ammonium- containing compound such as ammonium hydroxide
• the term "relatively high value” is a value of at least about 50% medium pores hi one preferred embodiment, a value of at least about 57% medium pores in another preferred embodiment and a value of at least 60% medium pores in another preferred embodiment.
• the catalysts of this invention are prepared using a solution of nitric acid (HNO 3 ) and ammonium hydroxide (NH 4 OH) to dissolve a bismuth component such as bismuth nitrate (Bi(NO 3 ) 3 ) or other bismuth salts or compounds, prior to adding the bismuth component to a solution of other components to form a slurry.
• a bismuth component such as bismuth nitrate (Bi(NO 3 ) 3 ) or other bismuth salts or compounds
• the Mil and Mill components can be added in any portions to either solution or to the slurry either before, during or after drying, but prior to calcination.
• the catalysts of this invention generally have pore size distribution including between about 0.1% and about 10.0% of small pores and between about 55% and about 80% of medium pores, preferably, the catalyst has a pore size distribution including between about 0.5% and about 7.5% of small pores and between about 60% and about 75% of medium pores, and particularly, the catalyst has a pore size distribution including between about 1.0% and about 5.0% of small pores and between about 60% and about 70% of medium pores.
• the catalysts of this invention are rendered more or less active by a calcination procedure to which they are subjected.
• the general calcination protocol is to calcine a dried catalyst at a temperature and for a time sufficient to obtain a catalyst having a desired activity, generally maximized activity, or to obtain a catalyst having the desired pore size distribution.
• the calcination temperature is above about 35O 0 C and the period of time is between about 2 hours and about 24 hours; however, shorter and longer times can be used.
• the calcination protocol also includes a soak step at a soak temperature and for a soak time sufficient to out-gas volatile components and components that form volatile components at high temperature.
• Particularly important components that produce volatile components during drying, soaking and calcining include nitrates and ammonium salts.
• the inventors believe that although the amount of nitrate and ammonium ions present in the dried composition is important for producing the desired pore size distribution, the careful control of drying, soaking and calcining conditions is also important in controlling the number of medium pores generated in the final catalyst. If the pre-calcined catalyst is heated too fast, the volatile components have insufficient time to out-gas and the activity of the resulting catalyst is reduced. Thus, by controlling catalyst drying, soaking and calcining, component out-gassing can be substantially completed before the catalyst is subjected to its final calcination temperature.
• the soak temperature is generally between about 180 0 C and about 250 ° C and the soak period of time is between about 1 hour and about 8 hours; however, shorter and longer times can be used.
• the soak step is designed to allow volatile components and components that form volatile components at high temperature to exit the catalyst gradually and not explosively or so rapidly that the catalyst pore distribution is damaged (collapses or produces too many non-medium pores).
• the protocols include an initial temperature ramp of about 0.25 ° C/min. to about 0.75 °C/min. for aperiod of time sufficient to raise the temperature to a desired soak step temperature and a final temperature ramp of about 0.25°C/min. to about 0.75°C/min for a period of time sufficient to raise the temperature to a desired calcination step temperature.
• the ramp rates are generally much higher as is well known in the art of commercial catalyst preparation.
• the catalyst of the present invention can be used without a carrier, or can be supported on or diluted with an inert carrier.
• Suitable inert carriers include, without limitation, silicates, silicas, aluminates, aluminas, silica-aluminas, silicon carbide, zirconias, titanias, magnesia, similar oxides or mixtures or combinations thereof.
• the catalysts of this invention are ideally suited for producing an unsaturated acid, preferably a conjugated unsaturated acid such as methacrylic acid by gas-phase catalytic oxidation of a vapor or vapor stream including an aldehyde feedstock such as isobutanal or mixtures of isobutanal and methacrolein at a temperature, at a pressure and for a time sufficient to convert the aldehydes in the aldehyde feedstock to methacrylic acid.
• the vapor stream used to contact the catalysts of the present invention generally includes sufficient amount of aldehyde in the aldehyde feedstock that is converted into an output stream containing a commercial quantity of methacrylic acid.
• the vapor or vapor stream includes from about 1 vol.% to about 20 vol.% of aldehyde in the aldehyde feedstock, and particularly, the vapor or vapor stream includes from about 3 to about 10 vol.% of aldehyde in the aldehyde feedstock.
• an aldehyde feed for the preparation of methacrylic acid may also contain large amounts of water and smaller amounts of impurities such as carbon monoxide, carbon dioxide, acetone, acetic acid, acrolein, methacrylic acid, isobutylene and other saturated and unsaturated hydrocarbons, lower saturated aldehydes, etc., but such impurities have substantially no effect on the conversion of the aldehydes to unsaturated acids.
• one class of preferred oxidizing agents for use in this invention is oxygen-containing gases having a higher oxygen content than air.
• Another preferred oxidizing agent for use in this invention is pure oxygen.
• An amount of the oxidizing agent used in the conversion of the aldehyde feedstock to methacrylic acid is set relative to a molar ratio of oxygen to aldehydes in the aldehyde feedstock. Generally, the molar ratio has a value between about 0.3 and about 4.0, preferably, the ratio has a value between about 0.8 and about 3.0.
• the oxidizing gas may be diluted with or contain an inert gas such as nitrogen, steam, carbon dioxide, etc., recycled oxygen-containing gases or mixtures or combinations thereof.
• the oxidation is generally carried out at a reaction pressure between sub-ambient and several atmospheres above ambient, preferably, the pressure is near ambient or as low as practical.
• the oxidation reaction using the catalysts of this invention is generally carried out at an elevated temperature, preferably, at a temperature between about 230°C and about 45O 0 C, particularly, at a temperature between about 250 0 C and about 400 0 C and more particularly, at a temperature between about 250 0 C and about 350 0 C.
• the oxidation reaction using the catalysts of this invention can be carried out using a variety of reactor systems including a fixed bed reactor (a reactor having one or more fixed catalyst beds or zones), a fluidized bed reactor (recycling catalyst in a gas entrained reaction environment), a moving bed reactor (catalyst moves in and out of the catalyst zone(s)), a continuous stirred tank reactor or any other reactor system geared for carrying out an oxidizing reaction such as the conversion of isobutyraldehyde to methacrylic acid.
• a fixed bed reactor a reactor having one or more fixed catalyst beds or zones
• a fluidized bed reactor recycling catalyst in a gas entrained reaction environment
• a moving bed reactor catalyst moves in and out of the catalyst zone(s)
• a continuous stirred tank reactor or any other reactor system geared for carrying out an oxidizing reaction such as the conversion of isobutyraldehyde to methacrylic acid.
• Example 1 illustrates the preparation of a specific catalyst of this invention including both B and Bi
• Comparative Example 1 illustrates the preparation of a catalyst excluding B and Bi
• Comparative Example 2 is a known mixed metal oxide isobutanal oxidation catalyst, which converts isobutanal to methacrolein
• Comparative Example 3 is a commercially available heteropolyacid catalyst. Comparative Example 2 and Comparative Example 3 are used to compare a catalyst of this invention for converting a mixture of isobutanal and methacrolein to methacrylic acid.
• the examples also include performance data for catalysts of this invention and the comparative examples.
• nitric acid 11.32g of nitric acid were added to 30 grams of DI water, then 7 mL of ammonium hydroxide (28 wt.% solution) were added to the nitric acid solution and then 5.32g of bismuth nitrate were added to the nitric acid/ammonium hydroxide solution with mixing and the mixture was stirred until the bismuth nitrate went into solution to form a Bi solution.
• the Bi solution was then added to the MoVCsPCu solution with mixing forming an MoVCsPCuBi slurry.
• the Bi solution causes a precipitation of the components as it is added to the MoVCsPCu solution or as the MoVCsPCu solution is added to the Bi solution.
• the resulting MoVCsPCuBi slurry was then heated to 95°C and then 2.56g of antimony trioxide and 0.68g of boric acid were added to the MoVCsPCuBi slurry with mixing to form an MoVCsPCuBiSbB slurry.
• the MoVCsPCuBiSbB slurry was then evaporated at about 100 0 C to form an evaporated mixture.
• the evaporated mixture was then dried at about 130 0 C for about 16 hours and sieved to obtain particles having a size between about 20 and 30 mesh.
• the particles were then heated to a soak temperature of 230°C at a rate of 0.5°C/min and held at the soak temperature for 3 hours in air.
• the particles were then heated to a calcination temperature of 380 ° C at a rate of 0.5°C/min. and held at the calcination temperature for 5 hours in air to form the Mo 12 P 1 5 V 05 Cu 0-1 Bi 0-5 Sb 0-8 CSj -0 B 05 O g catalyst.
• This example illustrates s the preparation of a 50 g batch of a catalyst of this invention having the composition Mo 12 P 1-5 V 0-5 Cu 0-1 Sb 0-8 Cs 1-0 O g .
• Example 1 catalyst 6 cc of the Example 1 catalyst was loaded into a fixed bed reactor and diluted with 9 cc of quartz chips.
• the catalyst was tested with a vapor stream having the following composition: 4 vol.% isobutyraldehyde (IBA), 30 vol.% steam with the balance being nitrogen and having two different oxygen to IBA mole ratios (O 2 /HC), where the oxygen-containing gas was air.
• IBA isobutyraldehyde
• O 2 /HC oxygen to IBA mole ratios
• the resulting effluent stream was analyzed by gas chromatography (GC).
• Example 1 The catalyst of Example 1 was also tested for the oxidation of methacrolein.
• the testing conditions were the same as those described above, except that 4 vol.% of methacrolein was fed instead of the 4 vol.% of EBA.
• the data obtained are tabulated in Table II. TABLE II MAC Conversion Performance of the Catalyst of Example 1
• the error in the conversion data is about ⁇ 3%.
• the catalysts of this invention be used to produce methacrylic acid from a stream containing isobutanal or isobutanal- :hacrolein mixtures.
• the compositional ranges for the aldehyde feedstock for use with catalysts of this invention range between about 5 wt.% isobutanal and about 95 wt.% :hacrolein to about 95 wt.% isobutanal and about 5 wt.% methacrolein.
• Another preferred :ture of aldehydes has a composition ranging between about 10 wt.% isobutanal and about 90 Vo methacrolein to about 90 wt.% isobutanal and about 10 wt.% methacrolein.
• Another preferred ;ture of aldehydes has a composition ranging between about 15 wt.% isobutanal and about 85 Vo methacrolein to about 85 wt.% isobutanal and about 15 wt.% methacrolein.
• Another preferred :ture of aldehydes has a composition ranging between about 20 wt.% isobutanal and about 80 Vo methacrolein to about 80 wt.% isobutanal and about 20 wt.% methacrolein.
• Another preferred iture of aldehydes has a composition ranging between about 25 wt.% isobutanal and about 75 Va methacrolein to about 75 wt.% isobutanal and about 25 wt.% methacrolein.
• aldehydes has a composition ranging between about 30 wt.% isobutanal and about 70 Vo methacrolein to about 70 wt.% isobutanal and about 30 wt.% methacrolein.
• Another preferred ;ture of aldehydes has a composition ranging between about 35 wt.% isobutanal and about 65 Vo methacrolein to about 65 wt.% isobutanal and about 35 wt.% methacrolein.
• aldehydes has a composition ranging between about 40 wt.% isobutanal and about 60 Vo methacrolein to about 60 wt.% isobutanal and about 40 wt.% methacrolein.
• Another preferred iture of aldehydes has a composition ranging between about 45 wt.% isobutanal and about 55 wt.% methacrolein to about 55 wt.% isobutanal and about 45 wt.% methacrolein.
• Another preferred mixture of aldehydes has a composition ranging between about 50 wt.% isobutanal and about 50 wt.% methacrolein.
• the term "about”, in the context of this invention, means ⁇ 2.5 wt.%. Of course, depending on starting material availability (IBA and MAC), the actual composition of the stream can actually be any composition within the ranges set forth above.
• the EBA conversion data includes a MAC conversion component as shown in Table HI.
• Example 3 was loaded in a fixed bed reactor and diluted with 9 cc of quartz chips. Each catalyst was tested with a feed of 2% IBA, 2% of MAC, 30% steam with the balance being nitrogen in the presence of oxygen at an oxygen to hydrocarbon mole ratio (O 2 /HC) of 2. The oxidation reactions were carried out at a reaction temperature of 284 0 C and at a feed flow rate of 50 seem. The products were analyzed by GC.

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