WO2025215480A1

WO2025215480A1 - Catalyst materials

Info

Publication number: WO2025215480A1
Application number: PCT/IB2025/053538
Authority: WO
Inventors: Jared Taylor; Vasily Simanzhenkov; Joel KOLLE
Original assignee: Nova Chemicals International SA
Current assignee: Nova Chemicals International SA
Priority date: 2024-04-09
Filing date: 2025-04-03
Publication date: 2025-10-16
Anticipated expiration: 2026-10-09

Abstract

The present disclosure relates to methods for treating catalyst materials, and to treated catalyst materials prepared thereby. An exemplary method includes contacting an uncalcined catalyst material with a thermal treatment at a temperature of 300°C to 495°C, wherein the uncalcined catalyst material includes an uncalcined catalyst including the formula Mo_aV_b(M₁)_c(M₂)_dO_x, wherein Mi is Bi, Te, Sb, or a mixture thereof; M₂ is Ta, Nb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; d is 0.005 to 0.1; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral. The thermal treatment described herein may include one or more of water nitrogen, carbon dioxide, and argon.

Description

CATALYST MATERIALS

TECHNICAL FIELD

The present disclosure relates to methods for treating uncalcined catalysts and catalyst materials. The catalysts treated by the methods disclosed herein are catalysts for the oxidative dehydrogenation (ODH) of alkanes, such as ethane.

BACKGROUND ART

Olefins like ethylene, propylene, and butylene are basic building blocks for a variety of commercially valuable polymers. Since naturally occurring sources of olefins do not exist in commercial quantities, polymer producers rely on methods for converting the more abundant lower alkanes into olefins. One such method for commercial scale producers is steam cracking, a highly endothermic process where steam -diluted hydrocarbons are subjected very briefly to a temperature of at least 600°C. The fuel demand to achieve the required temperatures and the need for equipment that can withstand that temperature add significantly to the overall cost. In addition, the high temperature promotes the formation of coke, which accumulates within the system, resulting in the need for costly periodic reactor shutdowns for maintenance and coke removal.

Selective oxidation processes, such as oxidative dehydrogenation (ODH), are an alternative to steam cracking that are exothermic and produce little or no coke. In ODH, a lower alkane, such as ethane, is mixed with oxygen in the presence of a catalyst and optionally an inert diluent, such as carbon dioxide (CO2) or nitrogen (N2) or steam (H2O), at temperatures as low as 300°C, to produce the corresponding alkene. Various other oxidation products may be produced in this process, including CO2 and acetic acid, among others. However, ODH suffers from lower conversion rates when compared to steam cracking, a fact that when combined with lower selectivity may have prevented ODH from achieving widespread commercial implementation. Additionally, conventional methods for activating ODH catalysts can involve multiple time-consuming and energy-intensive calcination steps. There is accordingly a need for ODH catalyst materials with high ethylene selectivity and activity, and for simpler methods of preparing such catalyst materials.

SUMMARY OF INVENTION

The present disclosure provides a method of treating an uncalcined catalyst material, the method including contacting the uncalcined catalyst material with a thermal treatment stream; wherein the uncalcined catalyst material includes an uncalcined catalyst including the formula: MOaVb(Ml)c(M2)dO: wherein:

Mi is Bi, Te, Sb, or a mixture thereof;

M2 is Ta, Nb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; d is 0.005 to 0.1; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; and wherein the thermal treatment stream includes one or more of water (H2O), nitrogen (N2), carbon dioxide (CO2), and argon (Ar).

In some embodiments, the thermal treatment stream includes the water and the water includes steam. In some embodiments, the thermal treatment stream includes 20 vol.% to 80 vol.% steam. In some embodiments, the thermal treatment stream further includes 20 vol.% to 80 vol.% nitrogen, carbon dioxide, argon, or any combination thereof.

In some embodiments, the thermal treatment stream includes 50 vol.% steam and 50 vol.% nitrogen. In some embodiments, the thermal treatment stream includes the nitrogen.

In some embodiments, the contacting of the uncalcined catalyst material with the thermal treatment stream is at a temperature of 275°C to 495°C and a pressure of up to 150 psig. In some embodiments, the contacting of the uncalcined catalyst material with the thermal treatment stream is at a temperature of 300°C to 450°C. In some embodiments, the contacting of the uncalcined catalyst material with the thermal treatment stream is for a time of up to 10 hours.

In some embodiments, the method further includes, before the contacting of the uncalcined catalyst material with the thermal treatment stream: combining the uncalcined catalyst, an inert carrier material, and water to form a first mixture; drying the first mixture; combining the dried first mixture and a lubricant to form a second mixture; and shaping the second mixture to provide the uncalcined catalyst material. In some embodiments, the drying of the first mixture is at a temperature of 60°C to 200°C.

In some embodiments, the inert carrier material includes alumina, silica, clay, or any combination thereof. In some embodiments, the lubricant includes graphite.

In some embodiments, the uncalcined catalyst includes a formula of MoaVbBicTadOx, MoaVbTecNbdOx, or MoaVbSbcTaaOx. In some embodiments, the uncalcined catalyst includes the formula Mo1V0.20-0.40Bi0.01-0.07Ta0.01-0.07Ox, M01V0.20- o.4oTeo.oi-o.o7Nbo.oi-o.o70x, or Mo1V0.20-0.40Sb0.01-0.07Ta0.01-0.07Ox. In some embodiments, the uncalcined catalyst includes the formula Mo1V0.31Bi0.05Ta0.05Ox, Mo1V0.30Te0.05 Nbo.tuOx, or Mo1V0.30Sb0.05Ta0.05Ox.

Also provided herein is a method for the oxidative dehydrogenation of ethane, the method including: contacting a catalyst material with a thermal treatment stream for a first period of time, the thermal treatment stream including one or more of water (H2O), nitrogen (N2), carbon dioxide (CO2), and argon (Ar); and contacting the catalyst material with a gaseous feed for a second period of time, the gaseous feed including ethane (C2H6) and oxygen (O2), to provide an effluent including ethylene (C2H4), wherein at a start of the first period of time the catalyst material includes an uncalcined catalyst including the formula:

MOaVb(Ml)c(M2)dOx wherein:

Mi is Bi, Te, Sb, or a mixture thereof;

M2 is Ta, Nb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; d is 0.005 to 0.1; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; and wherein the first period of time is shorter than the second period of time.

In some embodiments, the first period of time and the second period of time are consecutive. In some embodiments, the first period of time and the second period of time overlap. In some embodiments, the thermal treatment stream includes the water and the water includes steam.

In some embodiments, the thermal treatment stream includes 20 vol.% to 80 vol.% steam. In some embodiments, the thermal treatment stream further includes 20 vol.% to 80 vol.% nitrogen, carbon dioxide, argon (Ar), or any combination thereof. In some embodiments, the thermal treatment stream includes the nitrogen. In some embodiments, the nitrogen is the only gas used in the thermal treatment stream. In some embodiments, the thermal treatment stream includes 50 vol.% steam and 50 vol.% nitrogen. In some embodiments, the thermal treatment stream and the gaseous feed include, on a combined basis, 5 vol.% to 30 vol.% ethane, 2.5 vol.% to 20 vol.% oxygen, 30 vol.% to 70 vol.% water, and 20 vol.% to 60 vol.% of an inert gas.

In some embodiments, the contacting of the catalyst material with the thermal treatment stream is at a temperature of 275°C to 495°C and a pressure of up to 150 psig. In some embodiments, the contacting of the catalyst material with the thermal treatment stream is at a temperature of 300°C to 450°C. In some embodiments, the contacting of the catalyst material with the gaseous feed is at a temperature of 300°C to 495°C and a pressure of up to 150 psig.

In some embodiments, the uncalcined catalyst includes the formula MoaVbBicTaaOx, MoaVbTecNbdOx, or MoaVbSbcTaaOx. In some embodiments, the uncalcined catalyst includes the formula Mo1V0.20-0.40Bi0.01-0.07Ta0.01-0.07Ox, Mo1V0.20-0.40Te0.01-0.07Nb0.01-0.07Ox, or Mo1V0.20-0.40Sb0.01-0.07Ta0.01-0.07Ox. In some embodiments, the uncalcined catalyst includes the formula Mo1V0.31Bi0.05Ta0.05Ox, Mo1V0.30Te0.05 Nbo.o40x, or Mo1V0.30Sb0.05Ta0.05Ox.

In some embodiments, the catalyst material, after the first period of time, has an increased selectivity to one or both of ethylene and acetic acid at equivalent ethane conversion, as compared to the selectivity of the catalyst material at the start of the first period of time.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is an overlay of powder X-ray diffraction (PXRD) patterns of Catalyst C 1 (bottom) and Calcined Catalyst Cl (top) described herein.

Figure 2 is a PXRD pattern of Calcined Catalyst Material Cl -A described herein.

Figure 3 is an overlay of PXRD patterns of Calcined Catalyst Material Cl -A (bottom) and Calcined Catalyst Material Cl-B (top) described herein.

Figure 4 is a flowchart of mass balance method 400 used for analyzing catalyst material performance.

DESCRIPTION OF EMBODIMENTS

Selective oxidation (SO) is generally used in oxidative dehydrogenation (ODH) reactions to form alpha-olefins from corresponding alkanes, such as to form ethylene from ethane. Embodiments described herein provide a method of treating a catalyst material for the ODH process.

For the ODH of ethane, it is desired to have good selectivity toward high-value products (e.g., ethylene, acetic acid), while minimizing production of over-oxidized byproducts such as CO and CO2. Many previously disclosed ODH catalysts have shown high activity for the oxidative dehydrogenation of ethane but often suffer from insufficient selectivity to ethylene and/or require one or more calcination steps during catalyst preparation.

The present disclosure relates to methods of treating an uncalcined catalyst material including an uncalcined catalyst with a thermal treatment stream including one or more of water (H2O), nitrogen (N2), carbon dioxide (CO2), and argon (Ar), and to the resulting catalyst materials. The methods described herein can yield activated ODH catalyst materials that demonstrate ethylene selectivity and activity comparable to, or even better than, corresponding catalyst materials containing a catalyst that has undergone a calcination step during catalyst preparation. Such catalyst materials can achieve a similar product yield for a smaller reactor volume, as compared to corresponding catalyst materials containing a catalyst that has undergone a calcination step during catalyst synthesis. The methods described herein can be carried out in an ODH reactor, eliminating the need for transportation of calcined catalyst or catalyst materials, which can have lower crush strength as compared to the uncalcined catalyst or catalyst materials described herein.

Reference will now be made in detail to certain embodiments of the disclosed subject matter examples of which are illustrated in part in the accompanying figures. While the disclosed subject matter will be described in conjunction with the enumerated claims, it will be understood that the exemplified subject matter is not intended to limit the claims. Definitions

The terms “a”, “an”, and “the” are used herein to include one or more than one unless the context clearly dictates otherwise.

The term “or” is used to refer to a nonexclusive “or” unless otherwise indicated.

The statement “at least one of A and B” has the same meaning as “A, B, or A and B”.

The term “wt.%”, “% by weight”, “vol.%”, “% by volume”, “mol.%”, or “% by mol.” refer to a weight percentage of a component, a volume percentage of a component, or molar percentage of a component, respectively, based on the total weight, the total volume of material, or total moles, which includes the component. In a non-limiting example, 10 grams of component in 100 grams of the material is 10 wt.% of component.

As used herein, the term “oxidative dehydrogenation”, and the abbreviation “ODH”, refers to processes that couple the endothermic dehydrogenation of an alkane (CnH2n+2) with the strongly exothermic oxidation of hydrogen as is further described herein to form, amongst other things, alpha-olefins. In some embodiments, the alkane is one or more of ethane, propane, butane, pentane, hexane, octane, decane, and dodecane. In some embodiments, the alkane is ethane or propane. In some embodiments, the alkane is ethane. Fortesting catalysts, the ODH reactions herein are assumed to be referring to the ODH of ethane.

As used herein, the term “catalyst” refers to the active portion of a catalyst material that can promote oxidative dehydrogenation, such as the oxidative dehydrogenation of ethane to ethylene. The catalyst may be processed in further steps to form a catalyst material. The catalyst material may also be processed in further steps to form a final catalyst material.

As used herein, the term “catalyst material” refers to a material that includes an active catalyst that can promote the oxidative dehydrogenation of ethane to ethylene. The catalyst material may be substantially made up of the catalyst. The catalyst material may be a catalyst on a support, or a catalyst formulated with a carrier, such as an inert carrier material. The catalyst material can be a plurality of particles or a formed catalyst material. Non-limiting examples of formed catalyst materials include extruded catalyst materials, 3D- printed catalyst materials, spheronized catalyst materials, pressed catalyst materials, and cast catalyst materials. Non-limiting examples of pressed and cast catalyst materials includes pellets, such as tablets, ovals, and spherical particles. A binder may be used to aid in forming a catalyst material. Preparing a catalyst material may include a step of calcination. Catalyst materials that have been prepared without being subjected to a step of calcination may be referred to as “uncalcined catalyst materials”.

As used herein, “calcination” refers to thermal treatment at 500°C or greater, for at least 1 hour. The calcination of catalysts, in particular catalyst for ODH of alkanes, is known to the skilled person.

As used herein, the term “uncalcined”, when used in reference to a catalyst or catalyst material, means that the catalyst or catalyst material have not been subjected to calcination. An uncalcined catalyst will have a Brunauer-Emmett-Teller (BET) surface area as determined by nitrogen physisorption analysis that is greater than the surface area of the catalyst after calcination.

Methods of Treatment

Provided herein is a method of treating an uncalcined catalyst material including an uncalcined catalyst, the method including contacting the uncalcined catalyst material with a thermal treatment stream including one or more of water, nitrogen, carbon dioxide, and argon. As used herein, the term “thermal treatment stream” refers to a treatment stream that has a temperature above 100°C but below 500°C, such as between 250°C and 450°C. It is to be appreciated that the catalyst material may be substantially comprised of the catalyst and, therefore, the method of treating an uncalcined catalyst material is equally applicable to treating the catalyst. That is, the method of treating an uncalcined catalyst material encompasses a method of treating an uncalcined catalyst. In some embodiments, the thermal treatment stream is a non-stagnant, flowing stream.

In some embodiments, the thermal treatment stream includes the water in the form of steam. In some embodiments, the thermal treatment stream includes 20 vol.% to 80 vol.% steam. In some embodiments, the thermal treatment stream includes 20 vol.% to 70 vol.% steam, 20 vol.% to 60 vol.% steam, 30 vol.% to 80 vol.% steam, 30 vol.% to 70 vol.% steam, 30 vol.% to 60 vol.% steam, 40 vol.% to 80 vol.% steam, 40 vol.% to 70 vol.% steam, or 40 vol.% to 60 vol.% steam. In some embodiments, the thermal treatment includes 50 vol.% steam.

In some embodiments, the thermal treatment stream includes the water, in the form of steam, and further includes an inert gas. In some embodiments, the inert gas includes nitrogen (N2), carbon dioxide (CO2), and argon (Ar), or any combination thereof. In some embodiments, the inert gas includes the nitrogen. In some embodiments, the thermal treatment stream includes 20 vol.% to 80 vol.% of the inert gas. In some embodiments, the thermal treatment stream includes 20 vol.% to 70 vol.% of the inert gas, 20 vol.% to 60 vol.% of the inert gas, 30 vol.% to 80 vol.% of the inert gas, 30 vol.% to 70 vol.% of the inert gas, 30 vol.% to 60 vol.% of the inert gas, 40 vol.% to 80 vol.% of the inert gas, 40 vol.% to 70 vol.% of the inert gas, or 40 vol.% to 60 vol.% of the inert gas. In some embodiments, the thermal treatment stream includes 20 vol.% to 80 vol.% nitrogen, carbon dioxide, argon, or any combination thereof.

In some embodiments, the thermal treatment stream includes nitrogen. In some embodiments, the treatment includes 50 vol.% steam and 50 vol.% nitrogen.

In some embodiments, the contacting of the uncalcined catalyst material with the thermal treatment stream is at a temperature of 275°C to 495°C. In some embodiments, the contacting of the uncalcined catalyst material with the thermal treatment stream is at a temperature from 275°C to 450°C, from300°C to 470°C, from 350°C to 450°C, from 350°C to 425°C, from 350°C to 400°C, from 375°C to 425°C, or from 375°C to 400°C. In some embodiments, the contacting of the uncalcined catalyst material with the thermal treatment stream is at a pressure of up to 150 psig. In some embodiments, the contacting of the uncalcined catalyst material with the thermal treatment stream is at a pressure up to 125 psig, or up to 100 psig. In some embodiments, the contacting of the uncalcined catalyst material with the thermal treatment stream is at a pressure from 5 psig to 150 psig, 5 psig to 125 psig, 5 psig to 100 psig, 25 psig to 150 psig, 25 psig to 125 psig, 25 psig to 100 psig, 50 psig to 150 psig, 50 psig to 125 psig, or 50 psig to 100 psig.

In some embodiments, the contacting of the uncalcined catalyst with the thermal treatment stream is for a time of up to 10 hours, for example, up to 8 hours, up to 6 hours, up to 4 hours. In some embodiments, the contacting of the uncalcined catalyst with the thermal treatment stream is for a time from 0.5 hours to 10 hours, from 0.5 hours to 8 hours, from 0.5 hours to 6 hours, from 0.5 hours to 4 hours, from 1 hour to 10 hours, from 1 hour to 8 hours, from 1 hour to 6 hours, from 1 hours to 4 hours, from 2 hours to 10 hours, from 2 hours to 8 hours, from 2 hours to 6 hours, or from 2 hours to 4 hours.

In some embodiments, the catalyst material is contacted with the treatment feed in a reactor, such as an oxidative dehydrogenation (ODH) reactor. In some embodiments, the contacting of the catalyst material with the treatment feed is at a gas hourly space velocity (GHSV, described later herein) of 1,000 h'¹ to 30,000 h’¹, or 2,000 h'¹ to 5,000 h’¹. In some embodiments, the contacting of the catalyst material with the treatment feed is at a weight hourly space velocity (WHSV, described later herein) of 1 h'¹ to 30 h’¹, 1 h'¹ to 3 h’¹, or 2 h'¹ to 6 h’¹. In some embodiments, the linear space velocity of the treatment feed is at a linear space velocity of 1 cm/s to 500 cm/s.

Uncalcined catalysts that may be suitable for the methods disclosed herein include those described in WO2024189534A1 and WO2024189533A1, prepared in the absence of any calcination step.

The uncalcined catalyst includes molybdenum (Mo), vanadium (V), Ml, M2, and oxygen (O). Ml includes bismuth (Bi), tellurium (Te), antimony (Sb), or a mixture thereof. M2 includes tantalum (Ta), niobium (Nb), or a mixture thereof. The uncalcined catalyst is represented by the formula Mo_aVb(Ml)c(M2)dOx. In some embodiments, the uncalcined catalyst has the formula MoaVbBicTaaOx, MoaVbTecNbaOx, or MoaVbSbcTadOx.

In each of these formulations, a is 1.0, and x refers to at least the number of oxygen atoms necessary to render the uncalcined catalyst electrically neutral. In some embodiments, x is the number of oxygen atoms necessary to render the uncalcined catalyst electrically neutral. In some embodiments, x is greater than the number of oxygen atoms necessary to render the uncalcined catalyst electrically neutral, for example, wherein the uncalcined catalyst includes adsorbed or trapped oxygen-containing species.

The values of a, b, c, and d may refer to the values based on the amount of each starting material used to form the uncalcined catalyst. That is to say that the molar amounts of Mo, V, Mi, and M2 used in the synthesis of the uncalcined catalyst correspond to the values of a, b, and c in the catalyst formula, where b, c, and d are stated relative to the value of a being set to 1.0. The values of a, b, c, d may also refer to values measured by elemental analysis, for example by inductively coupled plasma mass spectroscopy (ICP-MS), neutron activation analysis (NAA), X-ray fluorescence (XRF), ion chromatography mass spectrometry (IC-MS), proton induced X-ray emission (PIXE), or energy-dispersive X-ray spectroscopy (EDX).

In the alternative, if specified, the values a, b, c, and d may only refer to the values determined by elemental analysis, for example by ICP-MS, NAA, XRF, IC-MS, PIXE, or EDX.

In each of these formulations, b is 0.01 to 0.5. In some embodiments, b is 0.2 to 0.4. In some embodiments, b is 0.25 to 0.35. In some embodiments, b is 0.3.

In each of these formulations, c is 0.005 to 0.2. In some embodiments, c is 0.01 to 0.1. In some embodiments, c is 0.01 to 0.07. In some embodiments, c is 0.04 to 0.07. In some embodiments, c is 0.05.

In each of these formulations, d is 0.005 to 0.1. In some embodiments, d is 0.01 to 0.1. In some embodiments, d is 0.01 to 0.07. In some embodiments, d is 0.03 to 0.06. In some embodiments, d is 0.05.

The formula with respect to the ratios of values a, b, c, and d can be selected to affect the activity, selectivity, purity, and stability of the uncalcined catalyst. In some embodiments, the uncalcined catalyst has the formula Mo1V0.20-0.40Bi0.01-0.07Ta0.01-0.07Ox, Mo1V0.20-0.40Te0.01-0.07Nb0.01-0.07Ox, or Mo1V0.20-0.40Sb0.01-0.07Ta0.01-0.07Ox.

In some embodiments, the uncalcined catalyst has the formula Mo1V0.31Bi0.05Ta0.05Ox, Mo1V0.30Te0.05 Nbo.o40x, or Mo1V0.30Sb0.05Ta0.05Ox, wherein the formula is determined based on the molar amounts of Mo, V, Ml, and M2 used to form the uncalcined catalyst.

In some embodiments, the values of a, b, c, and d are further determined by elemental analysis, for example, EDX, ICP-MS, or both. In some embodiments, the values of a, b, c, and d are determined by EDX to match the values of a, b, c, and d determined based on the amount of each starting material within 0.05, 0.04, 0.02, or 0.01.

The uncalcined catalyst can be prepared, for example, by forming a slurry including metal oxides, one or more of a bismuth compound, an antimony compound, and a tellurium compound, a reducing agent and water, and then heating the slurry at temperatures below 500°C, for example between 100°C and 200°C, to form the uncalcined catalyst in a hydrothermal synthesis reaction.

In some embodiments, the oxide of molybdenum is MoO3.

In some embodiments, the oxide of vanadium is V2O5.

In some embodiments, the bismuth compound, when present, is bismuth hydroxide.

In some embodiments, the antimony compound, when present, is an oxide of antimony.

In some embodiments, when present, the tellurium compound is TeCh.

In some embodiments, the oxide of tantalum, when present, is Ta2Os XH2O, and the oxide of niobium, when present, is bft^Os xtfcO.

In some embodiments, a ratio of water in the slurry to amount of catalyst formed is in a range between 0.1 mb water per gram of catalyst to 10 mb water per gram of catalyst. In some embodiments, the ratio of water in the slurry to amount of uncalcined catalyst formed is in a range between 0. 1 mb water per gram of uncalcined catalyst to 5 mb water per gram of uncalcined catalyst. In some embodiments, the slurry has a ratio of water to metal oxides in a range between 0.1 mb water per gram of metal oxides to 10 mb water per gram of metal oxides. As used herein, the phrase “water in the slurry” refers to the amount of water used to form the slurry for the hydrothermal synthesis reaction and does not include water that is not consumed or contaminated during the reaction or water that is used after the reaction. For example, “water in the slurry” does not include water present in the hydrothermal synthesis vessel for heat transfer and/or to maintain a humid atmosphere, or water that is used to wash the catalyst.

Any suitable reducing agent may be included in the slurry to form the uncalcined catalyst. In some embodiments, the reducing agent includes an alcohol, a carboxylic acid, an ester, or a metal oxide. In some embodiments, the reducing agent includes an alcohol, a carboxylic acid, an ester, or a metal oxide. Suitable examples of alcohol reducing agents include but are not limited to ethanol, methanol, reducing sugars, and polyols such as glycol and glycerol. Suitable examples of carboxylic acid reducing agents include but are not limited to oxalic acid, formic acid, acetic acid, and citric acid. Suitable examples of ester reducing agents include but are not limited to ethyl acetate, dimethyl carbonate, dimethyl oxalate, and diethyl oxalate. In some embodiments, the reducing agent includes a carboxylic acid. In some embodiments, the reducing agent is oxalic acid. The slurry can include one reducing agent, or two or more reducing agents. In some embodiments, the slurry includes no more than one reducing agent. The skilled person may choose the amount of reducing agent used in the slurry based in part on the nature of the reducing agent being used.

In some embodiments, the metal oxides present in the slurry have a particle size of less than 1 mm, such as greater than 60 mesh (less than 250 pm). In some embodiments, the metal oxides and the reducing agent are subjected to grinding, wet milling, dry milling, or crushing to modify the size of the metal oxides and the reducing agent.

In some embodiments, the slurry is heated in a hydrothermal synthesis vessel. In some embodiments, the slurry is formed in a hydrothermal synthesis vessel and subsequently heated in the hydrothermal synthesis vessel. In some embodiments, the slurry is transferred to a hydrothermal synthesis vessel after the slurry is formed, and then heated in the hydrothermal synthesis vessel. In some embodiments, the slurry is heated by ramping a temperature from ambient to a temperature in a range between 100°C and 200°C over a ramping time between 2 hours and 48 hours; and holding the temperature at a holding temperature in a range between 100°C and 200°C for a holding time between 12 hours and 120 hours.

In some embodiments, the method further includes washing the uncalcined catalyst with water. For example, the uncalcined catalyst may be washed with water until the filtrate is colorless.

In some embodiments, the uncalcined catalyst is combined with an inert carrier material to form an uncalcined catalyst material. In some embodiments, the inert carrier material includes precipitated synthetic silica, fumed synthetic silica, silica-alumina, alumina (e.g., a-alumina, y-alumina), titania, silicon carbide, MgAl spinel, an aluminate compound, an aluminosilicate compound, a zeolite, zirconia, doped zirconia, boron nitride, cerium oxide, doped cerium oxide, a perovskite, steel, clay, boehmite (aluminum oxide hydroxide), or any combination thereof. In some embodiments, the inert carrier material includes alumina. In some embodiments, the inert carrier material includes a-alumina, silica, clay, or any combination thereof. In some embodiments, the inert carrier material includes a-alumina. In some embodiments, the uncalcined catalyst material includes 1 wt.% to 80 wt.% of the inert carrier material, 10 wt.% to 70 wt.% of the inert carrier material, or 20 wt.% to 60 wt.% of the inert carrier material.

In some embodiments, the uncalcined catalyst material includes a lubricant. In some embodiments, the lubricant includes graphite, hexagonal boron nitride, calcium carbonate, a fatty acid, a fatty acid salt, methyl cellulose, polyvinyl alcohol, calcium carbonate, a stearate (e.g., magnesium stearate), PEG, glycerol, propylene glycol, or any combination thereof. In some embodiments, the lubricant includes graphite, hexagonal boron nitride, calcium carbonate, a fatty acid, a fatty acid salt, or any combination thereof. In some embodiments, the lubricant includes graphite.

In some embodiments, before the contacting of the uncalcined catalyst material with the thermal treatment stream, the method further includes combining the uncalcined catalyst, an inert carrier material, and water to form a first mixture, drying the first mixture, combining the dried first mixture and a lubricant to form a second mixture, and shaping the second mixture to provide the uncalcined catalyst material. In some embodiments, the inert carrier material is any inert carrier material described herein. In some embodiments, the lubricant is any lubricant described herein.

In some embodiments, the drying of the first mixture is at a temperature of 60°C to 200°C, such as for example, 60°C to 160°C, 60°C to 140°C, 80°C to 200°C, 80°C to 160°C, 80°C to 140°C, 100°C to 200°C, 100°C to 160°C, or 100°C to 140°C.

In some embodiments, the uncalcined catalyst material includes added bismuth hydroxide. By “added bismuth hydroxide” it is meant that bismuth hydroxide is added during preparation of the catalyst material (that is, when Ml includes Bi). Added bismuth hydroxide does not include bismuth hydroxide that is added during synthesis of the uncalcined catalyst, when the uncalcined catalyst includes bismuth. In some embodiments, the catalyst material includes 1 wt.% to 45 wt.% of added bismuth hydroxide. In some embodiments, the catalyst material includes 1 wt.% to 30 wt.% of added bismuth hydroxide, 1 wt.% to 20 wt.% of added bismuth hydroxide, 2 wt.% to 15 wt.% of added bismuth hydroxide, 5 wt.% to 15 wt.% of added bismuth hydroxide, or 5 wt.% to 10 wt.% of added bismuth hydroxide.

In some embodiments, the forming of the first mixture further incudes combining bismuth hydroxide with the uncalcined catalyst, the inert carrier material, and the water. In some embodiments, the combining is performed by contacting (e.g., mixing and/or grinding) the uncalcined catalyst with the bismuth hydroxide. In some embodiments, the combining is performed by wet mixing or dry mixing.

Also provided herein is a treated catalyst material, prepared by the method described herein.

ODH Methods

The treated uncalcined catalysts and catalyst materials disclosed herein are suitable as catalysts for oxidative dehydrogenation (ODH) reactions such as the ODH of ethane to, amongst other things, ethylene. Therefore, the present disclosure also provided a method for the oxidative dehydrogenation (ODH) of ethane, the method including contacting an uncalcined catalyst material with a thermal treatment stream for a first period of time, the thermal treatment stream including on or more of water (H2O), nitrogen (N2), carbon dioxide (CO2), and argon (Ar); and contacting the catalyst material with a gaseous feed for a second period of time, the gaseous feed including ethane (C2H6) and oxygen (O2), to provide an effluent including ethylene (C2H4). At a start of the first period of time, the catalyst material includes an uncalcined catalyst including the formula Mo_aVb(Mi)c(M2)dOx, wherein Mi is Bi, Te, Sb, or a mixture thereof; M2 is Ta, Nb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; d is 0.005 to 0.1; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral. The first period of time is shorter than the second period of time. In some embodiments, the thermal treatment stream includes the water in the form of steam. In some embodiments, the thermal treatment stream includes the nitrogen.

In some embodiments, the first period of time is up to 10 hours, for example, up to 8 hours, up to 6 hours, up to 4 hours, or up to 1 hour. In some embodiments, the first period of time is from 0.5 hours to 10 hours, 0.5 hours to 8 hours, 0.5 hours to 6 hours, 0.5 hours to 4 hours, 1 hour to 10 hours, 1 hour to 8 hours, 1 hour to 6 hours, 1 hours to 4 hours, 2 hours to 10 hours, 2 hours to 8 hours, 2 hours to 6 hours, or 2 hours to 4 hours.

In some embodiments, the first period of time and the second period of time are consecutive. In some embodiments, the first period of time and the second period of time overlap. For example, in some embodiments, the start of the first period of time and the start of the second period of time are the same. In another example, in some embodiments, the start of the second period of time is after the start of the first period of time, but before the end of the first period of time.

In some embodiments of the ODH method, the thermal treatment stream is any thermal treatment stream described herein. For example, the thermal treatment stream may include 20 vol.% to 80 vol.% steam and further includes 20 vol.% to 80 vol.% nitrogen, carbon dioxide, argon, or any combination thereof. In some embodiments, the thermal treatment stream includes the nitrogen. In some embodiments, the thermal treatment stream includes 50 vol.% steam and 50 vol.% nitrogen.

In some embodiments of the ODH method, the gaseous feed includes 10 vol.% to 50 vol.% ethane, for example, 10 vol.% to 30 vol.% ethane, or 20 vol.% ethane. In some embodiments, the gaseous feed includes 1 vol.% to 40 vol.% O2, for example, 1 vol.% to 25 vol.%, or 10 vol.% O2. In some embodiments, the gaseous feed further includes 50 vol.% to 90 vol.% of an inert gas, for example, 60 vol.% to 80 vol.% of the inert gas, or 70 vol.% of the inert gas. In some embodiments, the inert gas is any inert gas described herein, such as N2, CO2, Ar, or any combination thereof. In some embodiments, the inert gas includes N2. In some embodiments, the gaseous feed includes 20 vol.% ethane, 10 mol.% O2, and 70 mol.% N2.

In some embodiments, the first period of time and the second period of time overlap, and the thermal treatment stream and the gaseous feed include, on a combined basis, 5 vol.% to 30 vol.% ethane, for example, 5 vol.% to 20 vol.% ethane, 10 vol.% to 30 vol.% ethane, or 10 vol.% to 20 vol.% ethane.

In some embodiments, the first period of time and the second period of time overlap, and the thermal treatment stream and the gaseous feed include, on a combined basis, 2.5 vol.% to 20 vol.% O2, for example, 2.5 vol.% to 15 vol.% O2, 5 vol.% to 20 vol.% O2, or 5 vol.% to 15 vol.% O2.

In some embodiments, the first period of time and the second period of time overlap, and the thermal treatment stream and the gaseous feed include, on a combined basis, 30 vol.% to 70 vol.% water in the form of steam, for example, 30 vol.% to 55 vol.% steam, 40 vol.% to 70 vol.% steam, or 40 vol.% to 55 vol.% steam.

In some embodiments, the first period of time and the second period of time overlap, and the thermal treatment stream and the gaseous feed include, on a combined basis 20 vol.% to 60 vol.% of an inert gas, for example, 20 vol.% to 45 vol.% of the inert gas, 30 vol.% to 60 vol.% of the inert gas, or 30 vol.% to 45 vol.% of the inert gas. In some embodiments, the inert gas is any inert gas described herein.

In some embodiments, the treatment stream and the gaseous feed include, on a combined basis, 5 vol.% to 30 vol.%, 5 vol.% to 20 vol.%, 10 vol.% to 30 vol.%, or 10 vol.% to 20 vol.% ethane. In some embodiments of the process, the treatment stream and the gaseous feed include, on a combined basis, 2.5 vol.% to 20 vol.%, 2.5 vol.% to 15 vol.%, 5 vol.% to 20 vol.%, or 5 vol.% to 15 vol.% oxygen. In some embodiments of the process, the treatment stream and the gaseous feed include, on a combined basis, 30 vol.% to 70 vol.%, 30 vol.% to 60 vol.%, 40 vol.% to 70 vol.%, or 40 vol.% to 60 vol.% water. In some embodiments of the process, the treatment stream and the gaseous feed include, on a combined basis, 20 vol% to 60 vol.%, 20 vol.% to 50 vol.%, 30 vol.% to 60 vol.%, or 30 vol.% to 50 vol.% of an inert gas.

In some embodiments of the ODH method, the contacting of the catalyst material with the thermal treatment stream is as described herein. For example, in some embodiments of the ODH method, the contacting of the uncalcined catalyst material with the thermal treatment stream is at a temperature of 275°C to 495°C. In some embodiments, the contacting of the uncalcined catalyst material with the thermal treatment stream is at a temperature of 300°C to 470°C, 350°C to 450°C, 350°C to 425°C, 350°C to 400°C, 375°C to 425°C, or 375°C to 400°C.

In some embodiments, the contacting of the uncalcined catalyst material with the thermal treatment stream is at a pressure of up to 150 psig. In some embodiments, the contacting of the uncalcined catalyst material with the thermal treatment stream is at a pressure up to 125 psig, or up to 100 psig. In some embodiments, the contacting of the uncalcined catalyst material with the thermal treatment stream is at a pressure from 5 psig to 150 psig, 5 psig to 125 psig, 5 psig to 100 psig, 25 psig to 150 psig, 25 psig to 125 psig, 25 psig to 100 psig, 50 psig to 150 psig, 50 psig to 125 psig, or 50 psig to 100 psig. In some embodiments of the ODH method, the contacting of the catalyst material with the treatment stream is at a nitrogen pressure of 20 psig to 25 psig.

GHSV (gas hourly space velocity) is defined as volumetric flow of the reactor feed gas divided by the volume of the catalyst bed. As used herein, the term “volume of the catalyst bed” refers to the volume occupied by catalyst particles, optional diluent particles, and any void spaces within the catalyst bed. For GHSV values of Catalyst Materials, the catalyst bed is treated as catalyst only (not including support) where an assumption is made that the total volume of the catalyst material measured when multiplied by the wt. % of catalyst is the volume of the catalyst. The GHSV can be calculated based off the measured volume of the pressed particles (before mixing with quartz sand) and varies depending on each catalyst or catalyst material bulk density. For catalyst materials discussed herein, the GHSV reported is for the catalyst only, where an assumption was made that the total volume of the catalyst material measured when multiplied by the wt.% of catalyst is the volume of the catalyst.

In some embodiments of the ODH method, the contacting of the catalyst material with the treatment feed, the gaseous feed, or both is at a gas hourly space velocity (GHSV) of 1,000 h'¹ to 30,000 h’¹, or 2,000 to 5,000 h’¹. In some embodiments of the ODH method, the contacting of the catalyst material with the treatment feed, the gaseous feed, or both is at a weight hourly space velocity (WHSV) of 1 h'¹ to 30 h’¹, or 2 h'¹ to 6 h’¹. In some embodiments of the ODH method, the linear space velocity of the treatment feed, the gaseous feed, or both is at a linear space velocity of 1 cm/s to 500 cm/s. In some embodiments of the ODH method, the uncalcmed catalyst is any uncalcined catalyst described herein. For example, in some embodiments of the ODH method, the uncalcined catalyst has the formula MoaVbBicTaaOx, MoaVbTecNbdOx, or MoaVbSbcTaaOx. In some embodiments of the ODH method, the uncalcined catalyst has the formula Mo i Vo.2o-o.4oBio.o i-o.cnTao.o i-o.o?Ox, Mo1V0.20-0.40Te0.01-0.07Nb0.01-0.07Ox, or Mo 1 V o.2o-o.4oSbo.oi- 007Ta0.01-0.07Ox. In some embodiments, the uncalcined catalyst has the formula Mo1V0.31Bi0.05Ta0.05Ox, Mo1V0.30Te0.05 Nbo.o40x, or Mo1V0.30Sb0.05Ta0.05Ox, wherein the formula is determined based on the amount of each starting material used to form the uncalcined catalyst.

In some embodiments of the ODH method, the catalyst material, after the first period of time, has an increased selectivity to one or both of ethylene and acetic acid at equivalent ethane conversion, as compared to the selectivity of the uncalcined catalyst material (i.e., including the uncalcined catalyst) at the start of the first period of time.

Conversion of the ethane feed gas to products by the ODH process is calculated as a volume flow rate change of ethane in the product compared to feed ethane volume flow rate using the following formula:

In Equation 1, C is the percent (molar percent) of ethane feed gas that has been converted from ethane to another product (that is, ethane conversion) and X is the molar concentration of the corresponding compound in the gaseous effluent exiting the reactor at corresponding temperature.

Furthermore, the gas exiting the reactor can be analyzed by gas chromatography to determine catalyst or catalyst material selectivity to ethylene (that is, the percentage on a molar basis of ethane that forms ethylene). Selectivity to ethylene can be determined using the following equation:

In Equation 2, SEthyiene is the selectivity to ethylene and X is the molar concentration of the corresponding compound in the gaseous effluent exiting the reactor at corresponding temperature. As used herein, the phrase “selectivity to ethylene” refers to the percentage on a molar basis of converted or reacted ethane that forms ethylene.

In a microreactor unit, the 45% ethane conversion temperature of a catalyst can be determined by passing a feed gas over a catalyst bed in a reactor tube. The MRU reactor tube has an outer diameter of 0.5 inches and an internal diameter of 0.4 inches and length of 15 inches. For example, the reactor tube can be stainless-steel SWAGELOK® Tubing with a wall thickness of 0.049 inches. The feed gas can include ethane and oxygen having a molar ratio of 70:30 to 90: 10. For example, the feed gas can include ethane and oxygen having a molar ratio of 82: 18. Alternatively, the feed gas can include ethane, oxygen, and nitrogen. The molar ratio of ethane to oxygen to nitrogen can be 18:8:74 to 54: 18:28. For example, the molar ratio of ethane to oxygen to nitrogen can be 20: 10:70. The flow rate of the feed gas can be 70 standard cubic centimeters per minute (seem) to 80 seem. For example, the flow rate of the feed gas can be 75 seem (e.g., 74.6 seem). The catalyst bed consists of the oxidative dehydrogenation catalyst and a filler, such as quartz sand, 1:0.5 to 1:3 volume ratio, with the total weight for the oxidative dehydrogenation catalyst being 1.96 to 2.00 g. Any remaining space in the reactor tube (e.g., below or above the catalyst bed) is packed with an additional filler, such as quartz sand.

The 45% ethane conversion temperature is determined at a weight hourly space velocity (WHSV) of 3.57 h^-1, with the WHSV based on the weight of catalyst in the sample, and a gas hourly space velocity (GHSV) of 2,000 to 5,000 h^-1. As used herein, the expression “weight hourly space velocity” refers to the weight flow of the total feed gas divided by the weight of the catalyst. Typically, the inlet pressure is in the range of 1 pound per square inch gauge (psig) to 25 psig, such as from 20 psig to 23 psig, and the outlet pressure is in the range of 0 psig to 0.5 psig. The gas feed exiting the catalyst bed is analyzed by gas chromatography to determine the percent of various hydrocarbons (e.g., ethane and ethylene) and, optionally other gases such as O2, CO2, and CO.

In some embodiments, the uncalcined catalysts treated by the methods disclosed herein demonstrate increased selectivity to one or both of ethylene and acetic acid at equivalent ethane conversion, compared to calcined catalysts (that is, catalyst or catalyst materials that have undergone a step of calcination).

Other than in the operating examples or where otherwise indicated, all numbers or expressions referring to quantities of ingredients, reaction conditions, etc. used in the specification and claims are to be understood as modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending upon the desired properties, which the present disclosure desires to obtain. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

As used in this disclosure, the term “substantially” refers to a majority of, or mostly, as in at least 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least 99.999% or more.

Values expressed in a range format should be interpreted to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. That is, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of “1 to 10” is intended to include all sub-ranges between and including the recited minimum value of 1 and the recited maximum value of 10; that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10. Because the disclosed numerical ranges are continuous, they include every value between the minimum and maximum values. Unless expressly indicated otherwise, the various numerical ranges specified in this application are approximations.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical values, however, inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

In the methods described herein, the acts can be carried out in any order, except when a temporal or operational sequence is explicitly recited. Furthermore, specified acts can be carried out concurrently unless explicit claim language recites that they be carried out separately. For example, a claimed act of doing X and a claimed act of doing Y can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process. EXAMPLES PXRD Equipment

Powder X-ray diffraction (PXRD) data collection was performed using a PANalytical Empyrean powder X-ray diffractometer equipped with a monochromated Cu Ka X-ray source. Data was acquired between 3 - 80° 20 at a scan rate of l°/min. Data was analyzed using PANalytical HighScore software Version 4.8. Reagents

Molybdenum(VI) oxide (MoOs; 99.5%), vanadium(V) oxide (V2O5; 99.2%), bismuth hydroxide (Bi(OH)3; technical grade), antimony (III) oxide (Sb2C>3; 99%), tellurium (IV) oxide (TeCh; 99%), and oxalic acid dihydrate (ACS grade) were purchased from Sigma- Aldrich. The tantalum pentoxide hydrate (Ta2C>5 xbhO) was purchased from BassTech International, a-alumina was purchased from Fisher Scientific. The polyethylene glycol) 1000, Mowiol 8-88, graphite flakes and poly(acrylic acid) were purchased from Sigma-Aldrich. All reagents were used as is without any further purification. All water used was distilled deionized water.

Example 1. Preparation of Catalyst 1 and Calcined Catalyst C 1

Catalyst 1 was prepared with the solid reagents listed in Table 1. The solid reagents were added to a blender and mixed for 1 minute to blend and pulverize. The solid mixture was then transferred a 40 m glass bottle, after which 8.0 m of the distilled water solvent was used to rinse the grinder and transfer the residual solids to the bottle. The sample was stirred lightly with a glass stir rod to form a thick orange slurry, and then another 2.8 mb of water was used to rinse sample stuck to the stir rod back into the bottle. The vial was then placed in a glass-lined steel autoclave, and water was filled around the vial to the level of the slurry to aid heat transfer and to maintain a humid atmosphere in the vessel (~20 mb of water). The autoclave was then sealed and placed in an oven to heat from room temperature to 180°C over 12 hours, held at 180°C for 48 hours, then turned off to cool back to ambient temperature over 3 - 4 hours.

After reaction, the sample was a deep purple, hard solid. The sample was scraped from the bottle onto filter paper in a vacuum filtration setup and was washed with distilled water, to yield a deep blue filtrate. The sample was washed until the filtrate from the sample was nearly colorless, then was left to dry on the filter paper to obtain 29.4870 g of Catalyst 1, a shiny purple-black, powdered solid. Most of the sample (24.6823 g) was then calcined in a tubular autoclave under N2 flow (3.9 cm/min linear velocity at STP) for 8 hours at 80°C, after which it was heated to 600°C over 6 hours, held at 600°C for 2 hours, then the furnace was turned off and the samples cooled back to ambient conditions over approximately 12 hours, to yield Calcined Catalyst Cl, a deep purple-black powder. The mass of the solid samples before and after calcining is given in Table 2. Table 1. Reagents Used for Hydrothermal Synthesis of Catalyst 1

Table 2, Mass Before and After Calcination

Powder X-ray diffraction (PXRD) analysis was conducted on the sample before and after calcination (Figure 1). By PXRD, both samples were characterized as a doped molybdenum vanadium oxide phase known in academic literature as Ml. Before calcination, the sample was characterized with a minor impurity of MoOs, which converted into the desired phase after calcination.

Example 2, Preparation of Calcined Catalyst Material Cl -A

Calcined Catalyst Cl prepared according to Example 1 (10.0671 g) was added along with a-alumina (10.0771 g), poly(acrylic acid) (0.0199 g) and water (100 mb), and stirred overnight in a beaker to disperse. This mixture was then vacuum filtered and left to dry. The filter cake was then transferred back into the beaker along with polyethylene glycol) 1000 (0.3912 g), Mowiol 8-88 (0.6008 g), poly(acrylic acid) (0.0163 g) and water (90 mb), and stirred while heating at 85°C until the water had evaporated. The sample was then placed in an oven at 90°C overnight to dry completely. After drying, the sample was lightly pulverized using a mortar and pestle, sieved to obtain particles between 250 pm and 500 pm in size. 1 wt.% of graphite flakes were then added to the sieved particles and the mixture was shaken in a closed container to disperse. The graphite coated particles were then pelleted using a Dott Bonapace model CPR-6 automatic pellet press to obtain cylindrical pellets with approximately 5 mm length and 3 mm diameter.

The pellets were then placed in a quartz boat and heated first under dry air (1.8 cm/min linear velocity at STP) at a rate of 1.0°C/min to 400°C, held at 400°C for 1 hour, then heating was stopped and the furnace was left to cool back to ambient conditions over approximately 12 hours. Following the air treatment, the atmosphere was then purged with dry N2 (3.9 cm/min linear velocity at STP) for 8 hours, then under the same N2 flow, heated at a rate of 1 ,6°C/min to 600°C, held at 600°C for 2 hours, then heating was stopped and the furnace was left to cool back to ambient conditions over approximately 12 hours to yield Calcined Catalyst Material Cl -A. After the calcination/sintering procedure, the pellets’ mass was reduced by 5.28%. PXRD was collected on the sample following this procedure and showed that the sample was a mixture of the catalytically active Ml phase and a- alumina with a minor impurity of y-alumina (Figure 2).

Example 3, Preparation of Calcined Catalyst Material Cl-B

Calcined Catalyst Cl prepared according to Example 1 (3.8232 g) was added along with a-alumina (3.0462 g), bismuth(III) hydroxide (0.8645 g), poly(acrylic acid) (0.0078 g), poly(ethylene glycol) 1000 (0.1614 g), Mowiol 8-88 (0.2739 g), and water (50 mb), and the mixture was stirred while heating at 80°C until the water had evaporated. The sample was then placed in an oven at 90°C overnight to dry completely. After drying, the sample was lightly pulverized using a mortar and pestle, and sieved to obtain particles between 250 pm and 500 pm in size. 1 wt.% of graphite flakes were then added to the sieved particles and the mixture was shaken in a closed container to disperse. The graphite coated particles were then pelleted using a Dott Bonapace model CPR-6 automatic pellet press (dwell time approximately one second) to obtain cylindrical pellets with approximately 5 mm length and 3 mm diameter.

The pellets were then placed in a quartz boat and heated first under dry air (1.8 cm/min linear velocity at STP) at a rate of 1.0°C/min to 400°C, held at 400°C for 1 hour, then heating was stopped and the furnace was left to cool back to ambient conditions over approximately 12 hours. Following the air treatment, the atmosphere was then purged with dry N2 (3.9 cm/min linear velocity at STP) for 8 hours, then under the same N2 flow, heated at a rate of 1 ,6°C/min to 600°C, held at 600°C for 2 hours, then heating was stopped and the furnace was left to cool back to ambient conditions over approximately 12 hours to yield Calcined Catalyst Material Cl-B. After the calcination/sintering procedure, the mass of the pellets was reduced by 5.53%. PXRD was collected on the sample following this procedure and showed that the bismuth(III) hydroxide had reacted with some molybdenum components, and the catalyst was a mixture of the catalytically active Ml phase, Bi2(MC>4)3 and a-alumina (Figure 3) at an approximate weight ratio of 30/15/55, respectively, by crude Rietveld refinement. Example 4, Preparation of Catalyst 2 and Calcined Catalyst C2

Molybdenum(VI) oxide (MoOs), vanadium(V) oxide (V2O5), bismuth hydroxide (Bi(0H)3) and oxalic acid dihydrate were purchased from ThermoFisher Scientific.

Catalyst 2 was prepared with the solid reagents listed in Table 3. The solid reagents were added a 2 L glass beaker, after which 200 m of the distilled water solvent was added. The mixture was then stirred using an overhead stirrer for 5 min at 350 RPM rotation rate to form a thick orange slurry. Some effervescence and foaming was observed during stirring. The slurry was then transferred to a glass jar, and the residues were rinsed into the jar with the remaining 20 m of water. The jar was then placed in a 2 E steel Parr autoclave, and water was filled around the jar to the level of the slurry to aid heat transfer and to maintain a humid atmosphere in the vessel (~50 mb of water). The autoclave was then sealed and placed in an oven to heat from room temperature to 180°C over 12 hours, held at 180°C for 48 hours, then turned off to cool back to ambient over 3 - 4 hours.

After reaction, the sample was a deep purple hard solid. The sample was transferred from the jar into a 3 E beaker, and 2 E of water was added to the beaker. The mixture was stirred and decanted onto filter paper in a vacuum filtration set-up the sample was further washed and transferred to the filter paper with an additional 1 L of water, and was finally washed on the filter paper with another 1 L of water. The sample was washed until the filtrate from the sample was nearly colorless, then was left to dry on the filter paper, then was transferred to an oven to dry at 90°C for 3 days, yielding 694. 14 g of Catalyst 2, a purple -black solid.

Table 3 , Reagents used for Hydrothermal Synthesis of Catalyst 2

A subsample of Catalyst 2 was calcined in a tubular autoclave under N2 flow (3.9 cm/min linear velocity at STP) for 8 hours at 25 °C, after which it was heated to 600°C over 6 hours, held at 600°C for 2 hours, then the furnace was turned off and the sample was cooled back to ambient conditions over approximately 12 hours to yield Calcined Catalyst C2, a deep purple-black powder. The mass of the solid samples before and after calcining is given in Table 4.

Table 4, Mass Before and After Calcination

Example 5 , Preparation of Catalyst 3 and Calcined Catalyst C3

Catalyst 3 was prepared following the same procedure and using the same reagents as Example 4. The deviations from the Example 4 procedure were that a 300 mb Panautoclave was used, the solids and total volume of water was stirred in a PTFE cup, and the cup was placed in the autoclave without adding water between the PTFE cup and steel wall of the vessel. The amounts of reagents are listed in Table 5. The product was vacuum filtered and washed with approximately 400 mb of water after reaction. Drying in an oven overnight at 90°C yielded 6. 1759 g of Catalyst 3, a deep purple-black solid.

Table 5, Reagents Used for Hydrothermal Synthesis of Catalyst 3

A subsample of Catalyst 3 was calcined in a tubular autoclave under N2 flow (3.9 cm/min linear velocity at STP) for 8 hours at 25 °C, after which it was heated to 600°C over 6 hours, held at 600°C for 2 hours, then the furnace was turned off and the sample was cooled back to ambient conditions over approximately 12 hours to yield Calcined Catalyst C3, a deep purple-black powder.

Example 6, Preparation of Catalyst Material 3 -A

Dry, uncalcined Catalyst 3 (91.5 g) was added to a steel mixing bowl with bismuth hydroxide (4.9 g) and a-alumina (87.0 g). The bowl was placed on an Eirich EL-1 Laboratory mixer, and the dry solids were blended using a Z-type rotor for 120 s at a tip velocity of 20 m/s. Water was then slowly added to the solids while blending at the same rate over 120 s, then the tip velocity was increased to 25 m/s and the mixture was left to blend for 300 s. The mixture was then removed from the bowl and placed in an oven to dry at 90°C overnight (~16 hours).

After drying, the mixture was sieved to obtain particle sizes between 250 - 500 pm. Approximately 1 wt.% of graphite flakes were added to the sieved particles to act as a lubricant, then the mixture was shaken in a closed container to combine. The graphite- coated particles were then pelleted using a Dott Bonapace model CPR-6 automatic pellet press to obtain Catalyst Material 3-A, in the form of cylindrical pellets with approximately 5 mm length and 3 mm diameter.

Example 7, Calcined Catalyst Material C3-A

A subsample of pellets from Catalyst Material 3-A were used to prepare Catalyst Material C3-A. The pellets were placed in a quartz boat inside a tubular quartz furnace, then were heated to 400°C at a rate of 1 ,0°C/min under dry air flow (1.8 cm/min linear velocity at STP). The sample was held at 400°C for 1 hour, then heating was stopped, and the sample was cooled back to ambient passively over 8 hours. After, the quartz tube was purged with dry nitrogen (3.9 cm/min linear velocity at STP) for 8 hours, then heated to 600°C at 1.6°C/min, held at 600°C for 2 hours, then heating was stopped, and the furnace cooled passively over approximately 12 hours.

Example 8, Axial Crush Strength

Axial and radial crush strength of Calcined Catalyst Material Cl-B and Catalyst Material 3-A (uncalcined) were measured using a Torbal FB THOR precision digital force gauge. Results are shown in Table 6. Values shown were taken from an average of four pellets for axial crush strength and three pellets for radial crush strength. Pellets were 3 mm diameter and 5 mm length and prepared using the Dott Bonapace pellet press.

Table 6, Averaged Axial and Radial Crush Strength of Catalyst Materials

Example 9, Catalytic Testing

Equipment and Analysis

Catalyst materials were tested for their ability to catalyze the oxidative dehydrogenation (ODH) of ethane using a microreactor unit (MRU). The MRU has a reactor tube made from stainless-steel SWAGELOK® Tubing, which had an outer diameter of 0.5 inches (1.27 cm), an internal diameter of 0.4 inches (1.02 cm), and a length of 13.4- 15 inches (34.0 - 38.1 cm). Experimental temperatures of the MRU were measured using a 6-point WIKA Instruments Ltd. K-type thermocouple, which has an outer diameter of 0.125 inches (0.318 cm) and was inserted through the reactor. The 6-point thermocouple was used to measure and control the temperature within the catalyst bed. A room temperature stainless steel condenser was located after the reactor to collect water/acetic acid condensates. The gas product flow was allowed to either vent or was directed to an Agilent 6890 “hot gas” Gas Chromatograph (HGGC) during times when product gas analysis was required.

For catalytic testing, the pelleted catalyst materials were pulverized using a mortar and pestle, and particle sizes of 425 - 710 pm were sieved out for loading into the tubular reactor. Approximately 2 g of catalyst phase (for example, 4 g of catalyst was used if the sample contained 50 wt.% inert carrier) was placed in the reactor under a target gas flow rate of 150 seem (WHSV = 1.79 h-1) and atarget pressure of 23 psig. The target gaseous feed composition was 20 mol.% ethane, 10 mol.% oxygen and 70 mol.% N2 for all testing. Gas composition was determined by gas chromatography (GC) and analyzed using Chrom Perfect - Analysis, Version 6.1.10 for data evaluation. Samples were left on stream at temperature between 380°C and 420°C until data appeared to equilibrate, which was approximately 5 days.

For the MRU experiments, the mol.% ethane conversion temperature as determined at a WHSV of 1.79 h’¹, and a gas hourly space velocity (GHSV) in the range of 2,000 h'¹ to 5,000 h’¹. The gaseous product exiting the catalyst bed was directed to vent during runs. When the gaseous product was to be analyzed, it was momentarily redirected to the gas chromatography unit to determine the percent of ethane, ethylene, O2, CO2, CO, and, optionally, acetic acid.

Conversion (C) of the ethane feed gas was calculated as a volume flow rate change of ethane in the product compared to feed ethane mass flow rate using the following equation:

In Eq. 1, X is the molar concentration of the corresponding compound in the gaseous effluent exiting the reactor at corresponding temperature. The gas exiting the reactor was analyzed by GC to determine catalyst or catalyst material selectivity to ethylene (i.e., the percentage on a molar basis of ethane that forms ethylene). Selectivity to ethylene (SEthyiene) was determined using the following equation:

In the above equation 2, SEthyiene is the selectivity to ethylene and X is the molar concentration of the corresponding compound in the gaseous effluent exiting the reactor at corresponding temperature.

In order to close the mass balance for ODH experiments based on GC analysis of non-condensable products, an assumption was made that that all non-condensable gaseous products behave as ideal gases. The ideal gas equation of state is accurate in prediction of gas mixture behavior at operating pressure close to 1 atm -absolute. For the ODH experiments, the product gas samples were collected and injected to a lab GC at operating pressure close to 1 atm absolute. Therefore, the ideal gas behavior assumption is expected to generate accurate prediction of the gas mixture behavior. The bulk chemical reactions shown in Table 7 were assumed in order to calculate formed amounts of condensable products. The reactions in Table 7 were used for the purpose of stoichiometrically-balanced mass balance calculations and not to represent the actual chemical reactions occurring in the ODH reaction.

Table 7, Bulk Chemical Reactions Assumed for Mass Balance Methodology

“ As a result, the corresponding amount of water per mole of produced acetic acid and ethylene will be reduced. For example, 1 mole of acetic acid and 4 moles of ethylene would give 5 moles of water, when produced by reacting ethane and oxygen, but the same amount of both compounds would result in 2 moles of water for the same compounds to be produced by reaction of ethane and CO2. This results in 3 moles less water produced to make these compounds for each 2 moles of CO2 being consumed. These will be subtracted in the mass balance. Based on reactions shown in Table 7, Method 400 shown in Figure 4 was used in MS Excel. A GRG Nonlinear solving method was used with the objective of setting the absolute deviation of estimated and measured oxygen from the reactor to zero by modifying the acetic acid output in the solver.

In step 402, the total molar flow of C2 (ethane) into the reactor is calculated using Equation 3 :

F2Total = 100000*FTotal*(CEthane + 0.5 *CcO2) / 22.4 Eq. 3 wherein F2Totai is the total molar flow of C2 into the reactor, [pmol/min]; Frotai is the total feed flow to reactor (including all diluents), [seem]; CEthane is the molar fraction of ethane in total feed; Cco2 is the molar fraction of CO2 in total feed; and 22.4 is the molar volume at STP, [1/mol],

In step 404, the molar flow of all reactive compounds in product effluent from the reactor is calculated excluding inert diluents.

The total molar flow of acetic acid in the product, [mmol/min] (FAAOUI) is estimated by Equation 4:

FAAOUI = y (first estimate: y = 1 [mmol/min]) Eq. 4

The total molar flows of C2 in non-condensable compounds in the reactor product is calculated using Equation 5 :

F2outx ⁼ F2Total * (Cxout/( SCxout)) * ((F2Total - FAAout) / F2Total) Eq. 5 wherein F2outx is the total molar flow of C2 of x, [mmol/min]; Cxout is the molar fraction of x in the reactor product; and x is Ethane, Ethylene, CO2, or CO.

The total molar flow of O2 from the reactor is calculated using the following algorithm:

If F20UTC02 - (100000*F_Totai*(0.5*Cco2) / 22.4)) > 0 then use Equation 6:

Fo2out = (100000*F_Total*(0.5*Co2) / 22.4)) - 0.5* F2outethane - 3.5* F2OUTCO2- 2.5* F2outco - 1.5* FoutAAout Eq. 6

If F20UTC02 - (100000*F_Totai*(0.5*Cco2) / 22.4)) < 0 then use Equation 7:

F₀2out = (100000*F_Total*(0.5*Co2) / 22.4)) - 0.5* F2outethane + ABS(3.5* F20UTC02) - 2.5* F2outco - 1.5* FoutAAout Eq. 7

The total molar flow of H2O from the reactor is calculated using Equation 8:

FffiOoutx = FH2O + F2outethane - 3 * F2OUTCO2- 3 *F2outCO - FAAout Eq. 8

In step 406, the molar fractions of all reactive compounds in the product effluent from the reactor are calculated on the dry (water free) basis, using FAAout from step X04. The molar fraction of acetic acid in the product is calculated using Equation 9: CAAoutcalc ⁼ FAAout /( FAAout + SFxout + Fo2out) Eq. 9

The molar fraction of C2 in ethane, ethylene, CO2 and CO in the product is calculated using Equation 10:

Cxoutcalc ⁼ F2outx /( FAAout + SFxout + Fo2out) Eq. 10

The molar fraction of oxygen in the product is calculated using Equation 11 :

Co2outcalc ⁼ Fo2out /( FAAout + SFxout + Fo2out) Eq. 11

In step 408, the absolute deviation of estimated and measured O2 in the noncondensable product from the reactor is calculated using Equation 12:

D02 = Co2outcalc - (C02 / (CEthane +CEthylne + 0.5*CcO2 + 0.5Cco+ C02) *

(1 - CAAoutcalc)) Eq. 12

As shown in step 410, if D02 is less than 1 O'⁴, proceed to step 412. If D02 is not less than 10'⁴, return to step 404 and repeat. On the repeated steps, FAAout = y (wherein y = new estimate [mmol/min]) is changed, and the steps are repeated to determine whether D02 is closer to the target in step 410.

In step 412, ethane conversion is calculated using Equation 13: and selectivity toward each product is calculated using Equation 14: wherein CxoutCalc ⁼ CEthyleneoutCalc, CAAoutCalc, 0.5 * CcO2outCalc Or 0.5 * CcOOutcalc .

Catalyst Performance - Catalyst 1

Testing of Catalyst 1 -based samples (Table 8) offered a comparison of the MoVTaBiOx-type catalysts with one heating step (600°C under N2 flow; Calcined Catalyst Cl), and three heating steps (600°C under N2 flow, then 400°C under air, then again 600°C under N2 flow; Calcined Catalyst Material Cl -A and Cl-B). The difference between Calcined Catalyst Material Cl -A and Cl-B is that Cl -A was formulated with only a- alumina, whereas Cl-B was formulated with a-alumina and bismuth hydroxide. Table 8, Comparison of Catalyst 1 -Based Samples at Equivalent Ethane Conversion

The results show that there was little difference in performance of the catalyst samples after one or three thermal treatment steps, unless a bismuth hydroxide promoter is added to the pelleted catalyst with the inert carrier material.

A steam treatment of Calcined Catalyst Material Cl-B was also trialed, whereby the sample was treated with 150 seem flow (WHSV = 1.79 h'¹) of a 50/50 vol.% mixture of steam and N2 at 400°C at 8.5 psig for 4 hours. Afterwards the sample was brought back to the same process conditions as before the treatment and left on stream to equilibrate. Results for both samples are shown in Table 9.

Table 9, Comparison of Calcined Catalyst Material Cl-B Before and After Steam Treatment

The results show that that treatment of Calcined Catalyst Material Cl-B with 50/50 vol.% steam/N2 on stream had little to no effect on catalyst performance within the margins of error of testing.

Catalyst Performance - Catalyst 2

Testing of Catalyst 2-based samples offered a comparison of the MoVTaBiOx-type catalyst without any calcination step (Catalyst 2) or with one thermal treatment at 600°C under N2 flow (Calcined Catalyst C2). Both samples were also treated with 150 seem flow (WHSV = 1.79 h'¹) of a 50/50 vol.% mixture of steam and N2 at 400°C at 8.5 psig for 4 hours. Afterwards the samples were brought back to the same process conditions as before the treatment and left on stream to equilibrate. Results are shown in Table 10. Table 10. Comparison of Catalyst 2-Based Samples

The results show that uncalcined Catalyst 2 was extremely active in ethane ODH, with high conversion of ethane at temperatures almost 100°C lower than the same catalyst after calcination, although with lower selectivity. Treatment of Catalyst 2 with 50/50 vol.% steam/N2 on stream caused a dramatic improvement in catalyst performance, increasing selectivity to ethylene by 6.8%, reducing selectivity to acetic acid by 1.4% and reducing selectivity to COx (undesired byproducts) by 5.4%, with a 6.2% loss in ethane conversion activity at 275 °C.

Steam treatment of Calcined Catalyst C2 offered no significant improvement in ethylene vs. acetic acid selectivity, while reducing ethane conversion activity by 1.5%. Finally, in comparing both calcined and uncalcined steam-treated catalysts, the total selectivity to valuable products remained higher for the uncalcined catalyst (92.9% vs. 89.7%) at comparable ethane conversion (52.7% vs. 50.9%) and gas flow rates (WHSV = 1.79 h'¹).

Catalyst Performance - Catalyst 3

Testing of Catalyst 3-based samples offered another comparison of the MoVTaBiOx-type catalyst without any calcination step or with one thermal treatment at 600°C under N2 flow. In this case, the uncalcined catalyst was blended with inert support and pelleted (Catalyst Material 3 -A) prior to loading into the reactor. Both samples were also treated with 150 seem flow (WHSV = 1.79 h'¹) of a 50/50 vol.% mixture of steam and N2 at 400°C at 8.5 psig for 4 hours. Afterwards, the samples were brought back to the same process conditions as before the treatment and left on stream to equilibrate. For the uncalcined sample, reagent gas flow rate was also increased four-fold from 152 seem to 609 seem and temperature was adjusted to reach -50% ethane conversion. Results are shown in Table 11.

Table 11. Comparison of Catalyst 3-Based Samples

The results show that uncalcined, formulated, and pelleted Catalyst 3 was highly active in ethane ODH, with high conversion of ethane at temperatures significantly lower than the same catalyst after calcination, although with lower selectivity. Treatment of Catalyst 3 with 50/50 vol.% steam/N2 on stream caused a dramatic improvement in catalyst performance, increasing selectivity to ethylene by 13.4%, reducing selectivity to acetic acid by 0.6% and reducing selectivity to COx (undesired byproducts) by 12.8%.

Steam treatment of Calcined Catalyst C3 offered some improvement in ethylene vs. acetic acid selectivity, while slightly reducing activity, but overall selectivity to COx remained almost constant. Finally, in comparing both calcined and uncalcined steam-treated catalysts, the total selectivity to valuable byproducts remained higher for the uncalcined catalyst (92.8% vs. 90.0%) at comparable ethane conversion (55.0% vs. 53.2%) and gas flow rates (WHSV = 1.79 h'¹).

Given the high activity, flow rates of reagent gases could be increased four-fold with the uncalcined catalyst to reach comparable operating temperatures to the calcined catalyst (Table 12). At the increased flow rate, Catalyst Material 3 -A still demonstrated improved selectivity to commercially valuable products as compared Calcined Catalyst C3 (91.0% vs. 90.0%), while producing them at ~4x increased molar output. Catalyst preparation procedures including steam treatment of uncalcined catalysts can accordingly yield a far more active catalyst in a shorter period with less energy input, while greatly increasing yield in the ethane ODH process.

Table 12, Comparison of Molar Inputs and Outputs of Reagents for Steam -Treated Catalyst 3-Based Samples at Comparable Reactor Temperatures.

Example 10. Gas Sorption Analysis

Two batches of catalyst were prepared for gas sorption analysis using the following procedure. All components listed in Table 13 were added to a 1.8 L PTFE beaker and stirred with a PTFE-coated overhead stirrer for 45 minutes, forming an orange slurry. The PTFE beaker was then placed in a 2 L steel Parr autoclave and water (50 mb) was fdled around the beaker to maintain a humid atmosphere in the vessel. The autoclave was then sealed and placed in an oven to heat from room temperature to 180°C over 12 hours. The oven temperature was held at 180°C for 48 hours, then heating was stopped and the oven was cooled back to ambient temperature over 3 - 4 hours. The autoclave was then vented in a fume hood and the solid product was transferred to a 3 L glass beaker with 1 L of distilled deionized water, and stirred with a PFTE-coated overhead stirrer for 2 hours. A deep purple solid was then recovered by vacuum fdtration and washed with an additional 3 L of water. The solid was dried overnight at 90°C, to provide the uncalcined catalyst sample.

To prepare the calcined catalyst sample, the dried solid sample of uncalcined catalyst as described above was placed in a tubular quartz furnace under nitrogen flow (3.9 cm/min linear velocity at STP), for a period of time sufficient to purge the cell with nitrogen. After purging, the furnace was heated to 600°C at a rate of 1.6°C/min, and held at 600°C for 2 hours. The furnace was then turned off, and the sample was cooled to ambient conditions over approximately 12 hours to provide the calcined sample. Table 13, Reagents used for Hydrothermal Synthesis of Catalysts for Gas Sorption Analysis.

Nitrogen physisorption analysis was collected using a Micromeritics Instruments TriStar gas sorption analyzer. The powdered samples were loaded into physisorption cells and degassed at 120°C overnight (> 12 h) prior to adsorption measurements. Nitrogen gas sorption analysis was collected at -196°C using 99.999% N2, with the sample holders immersed in a liquid nitrogen bath. A BET model was used to determine the surface area of the sample. Total pore volume was calculated at the relative pressure P/PO = 0.99, to exclude inter particle porosity.

Table 14, Gas Sorption Data for Uncalcined and Calcined Catalysts Prepared According to Example 12,

Non-limiting limiting embodiments of the present disclosure include the following: Embodiment A: A method of treating an uncalcined catalyst material, the method comprising contacting the uncalcined catalyst material with athermal treatment stream; wherein the uncalcined catalyst material comprises an uncalcined catalyst comprising the formula: Mo_aVb(Mi)c(M2)dOx wherein: Mi is Bi, Te, Sb, or a mixture thereof; M2 is Ta, Nb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; d is 0.005 to 0.1; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; and wherein the thermal treatment stream comprises one or more of water (H2O), nitrogen (N2), carbon dioxide (CO2), and argon (Ar). Embodiment B. The method according to Embodiment A, wherein the thermal treatment stream comprises the water and the water comprises steam.

Embodiment C. The method according to Embodiment A or B, wherein the thermal treatment stream comprises 20 vol.% to 80 vol.% steam.

Embodiment D. The method according to Embodiment B or C, wherein the thermal treatment stream further comprises 20 vol.% to 80 vol.% nitrogen, carbon dioxide, argon, or any combination thereof.

Embodiment E. The method according to Embodiment D, where the thermal treatment stream comprises 50 vol.% steam and 50 vol.% nitrogen.

Embodiment F. The method according to Embodiment A, wherein the thermal treatment stream is nitrogen.

Embodiment G. The method according to Embodiment A, B, C, D, E, or F, wherein the contacting of the uncalcined catalyst material with the thermal treatment stream is at a temperature of 275°C to 495°C and a pressure of up to 150 psig.

Embodiment H. The method according to Embodiment A, B, C, D, E, or F, wherein the contacting of the uncalcined catalyst material with the thermal treatment stream is at a temperature of 300°C to 450°C.

Embodiment I. The method according to Embodiment A, B, C, D, E, F, or G, wherein the contacting of the uncalcined catalyst material with the thermal treatment stream is for a time of up to 10 hours.

Embodiment J. The method according to Embodiment A, B, C, D, E, F, G, H, or I further comprising, before the contacting of the uncalcined catalyst material with the thermal treatment stream: combining the uncalcined catalyst, an inert carrier material, and water to form a first mixture; drying the first mixture; combining the dried first mixture and a lubricant to form a second mixture; and shaping the second mixture to provide the uncalcined catalyst material.

Embodiment K. The method according to Embodiment J, wherein the drying of the first mixture is at a temperature of 60°C to 200°C.

Embodiment L. The method according to Embodiment J or K, wherein the inert carrier material comprises alumina, silica, clay, or any combination thereof.

Embodiment M. The method according to Embodiment J, K, or L, wherein the lubricant comprises graphite. Embodiment N. The method according to Embodiment A, B, C, D, E, F, G, H, I, J, K, L, or M, wherein the uncalcined catalyst comprises a formula of MoaVbBicTaaOx, MoaVbTecNbdOx, or MoaVbSbcTaaOx.

Embodiment O. The method according to Embodiment A, B, C, D, E, F, G, H, I, J, K, L, M, or N, wherein the uncalcined catalyst comprises the formula Mo1V0.20-0.40Bi0.01- o.o7Tao.oi-o.o70x, Mo1V0.20-0.40Te0.01-0.07Nb0.01-0.07Ox, or Mo1V0.20-0.40Sb0.01-0.07Ta0.01-0.07Ox.

Embodiment P. The method according to Embodiment A, B, C, D, E, F, G, H, I, J, K, L, M, N, or O, wherein the uncalcined catalyst comprises the formula Mo1V0.31Bi0.05Ta0.05Ox, Mo1V0.30Te0.05 Nbo.o40x, or Mo1V0.30Sb0.05Ta0.05Ox.

Embodiment Q. A treated catalyst material, prepared by the method of Embodiment A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, or P.

Embodiment R. A method for the oxidative dehydrogenation of ethane, the method comprising: contacting a catalyst material with a thermal treatment stream for a first period of time, the thermal treatment stream comprising one or more of water (H2O), nitrogen (N2), carbon dioxide (CO2), and argon (Ar); and contacting the catalyst material with a gaseous feed for a second period of time, the gaseous feed comprising ethane (C2H6) and oxygen (O2), to provide an effluent comprising ethylene (C2H4); wherein: at a start of the first period of time the catalyst material comprises an uncalcined catalyst comprising the formula: MoaVb(Mi)c(M2)aOx wherein: Mi is Bi, Te, Sb, or a mixture thereof; M2 is Ta, Nb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; d is 0.005 to 0.1; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; and wherein the first period of time is shorter than the second period of time.

Embodiment S. The method according to Embodiment R, wherein the first period of time and the second period of time are consecutive.

Embodiment T. The method according to Embodiment R, wherein the first period of time and the second period of time overlap.

Embodiment U. The method according to Embodiment R, S, or T, wherein the thermal treatment stream comprises the water and the water comprises steam.

Embodiment V. The method according to Embodiment R, S, T, or U, wherein the thermal treatment stream comprises 20 vol.% to 80 vol.% water.

Embodiment W. The method according to Embodiment V, wherein the thermal treatment stream further comprises 20 vol.% to 80 vol.% nitrogen, carbon dioxide, argon, or any combination thereof. Embodiment X. The method according to Embodiment W, wherein the thermal treatment stream comprises 50 vol.% steam and 50 vol.% nitrogen.

Embodiment Y. The method according Embodiment T, U, V, W, or X, wherein the thermal treatment stream and the gaseous feed comprise, on a combined basis, 5 vol.% to 30 vol.% ethane, 2.5 vol.% to 20 vol.% oxygen, 30 vol.% to 70 vol.% water, and 20 vol.% to 60 vol.% of an inert gas.

Embodiment Z. The method according to Embodiment R, S, or T, wherein the thermal treatment stream comprises the nitrogen.

Embodiment AA. The method according to Embodiment R, S, T, U, V, W, X, Y, or Z, wherein the contacting of the catalyst material with the thermal treatment stream is at a temperature of 275°C to 495°C and a pressure of up to 150 psig.

Embodiment AB. The method according to Embodiment R, S, T, U, V, W, X, Y, or Z, wherein the contacting of the catalyst material with the thermal treatment stream is at a temperature of 300°C to 450°C.

Embodiment AC. The method according to Embodiment R, S, T, U, V, W, X, Y, Z, AA, or AB, wherein the contacting of the catalyst material with the gaseous feed is at a temperature of 300°C to 495°C and a pressure of up to 150 psig.

Embodiment AD. The method according to Embodiment R, S, T, U, V, W, X, Y, Z, AA, AB, or AC, wherein the uncalcined catalyst comprises the formula MoaVbBicTaaOx, MoaVbTecNbdOx, or MoaVbSbcTaaOx.

Embodiment AE. The method according to Embodiment R, S, T, U, V, W, X, Y, Z, AA, AB, AC, or AD, wherein the uncalcined catalyst comprises the formula M01V0.20- o.4oBio.oi-o.o7Tao.oi-o.o70x, Mo1V0.20-0.40Te0.01-0.07Nb0.01-0.07Ox, or Mo1V0.20-0.40Sb0.01-0.07Ta0.01- 0.07Ox.

Embodiment AF. The method according to Embodiment R, S, T, U, V, W, X, Y, Z, AA, AB, AC, AD, or AE, wherein the uncalcined catalyst comprises the formula Mo1V0.31Bi0.05Ta0.05Ox, Mo1V0.30Te0.05 Nbo.o40x, or Mo1V0.30Sb0.05Ta0.05Ox.

Embodiment AG. The method according to Embodiment R, S, T, U, V, W, X, Y, Z, AA, AB, AC, AD, AE, or AF, wherein the catalyst material, after the first period of time, has an increased selectivity to one or both of ethylene and acetic acid at equivalent ethane conversion, as compared to the selectivity of the catalyst material at the start of the first period of time.

Other implementations are also within the scope of the following claims. INDUSTRIAL APPLICABILITY

Methods of treating catalysts and catalyst materials for oxidative dehydrogenation of alkanes, such as the oxidative dehydrogenation of ethane to ethylene.

Claims

1. A method of treating an uncalcined catalyst material, the method comprising contacting the uncalcined catalyst material with a thermal treatment stream; wherein the uncalcined catalyst material comprises an uncalcined catalyst comprising the formula:

MOaVb(Ml)c(M2)dOx wherein:

Mi is Bi, Te, Sb, or a mixture thereof;

M2 is Ta, Nb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; d is 0.005 to 0.1; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; and wherein the thermal treatment stream comprises one or more of water (H2O), nitrogen (N2), carbon dioxide (CO2), and argon (Ar).

2. The method according to claim 1, wherein the thermal treatment stream comprises the water and the water comprises steam.

3. The method according to claim 1 or claim 2, wherein the thermal treatment stream comprises 20 vol. % to 80 vol.% steam.

4. The method according to claim 2 or 3, wherein the thermal treatment stream further comprises 20 vol.% to 80 vol.% nitrogen, carbon dioxide, argon, or any combination thereof.

5. The method according to claim 4, where the thermal treatment stream comprises 50 vol.% steam and 50 vol.% nitrogen.

6. The method according to claim 1, wherein the thermal treatment stream comprises the nitrogen.

7. The method according to any one of claims 1 to 6, wherein the contacting of the uncalcined catalyst material with the thermal treatment stream is at a temperature of 275 °C to 495°C and a pressure of up to 150 psig.

8. The method according to any one of claims 1 to 6, wherein the contacting of the uncalcined catalyst material with the thermal treatment stream is at a temperature of 300°C to 450°C.

9. The method according to any one of claims 1 to 8, wherein the contacting of the uncalcined catalyst material with the thermal treatment stream is for a time of up to 10 hours.

10. The method according to claim any one of claims 1 to 9, further comprising, before the contacting of the uncalcined catalyst material with the thermal treatment stream: combining the uncalcined catalyst, an inert carrier material, and water to form a first mixture; drying the first mixture; combining the dried first mixture and a lubricant to form a second mixture; and shaping the second mixture to provide the uncalcined catalyst material.

11. The method according to claim 10, wherein the drying of the first mixture is at a temperature of 60°C to 200°C.

12. The method according to claim 10 or 11, wherein the inert carrier material comprises alumina, silica, clay, or any combination thereof.

13. The method according to any one of claims 10 to 12, wherein the lubricant comprises graphite.

14. The method according to any one of claims 1 to 13, wherein the uncalcined catalyst comprises a formula of MoaVbBicTaaOx, MoaVbTecNbdOx, or MoaVbSbcTaaOx.

15. The method according to any one of claims 1 to 14, wherein the uncalcined catalyst comprises the formula Mo1V0.20-0.40Bi0.01-0.07Ta0.01-0.07Ox, Mo1V0.20-0.40Te0.01-0.07Nb0.01-0.07Ox, or Mo1V0.20-0.40Sb0.01-0.07Ta0.01-0.07Ox.

16. The method according to any one of claims 1 to 15, wherein the uncalcined catalyst comprises the formula Mo1V0.31Bi0.05Ta0.05Ox, Mo1V0.30Te0.05 Nbo.cwOx, or Mo1V0.30Sb0.05Ta0.05Ox.

17. A treated catalyst material, prepared by the method of any one of claims 1 to 16.

18. A method for the oxidative dehydrogenation of ethane, the method comprising: contacting a catalyst material with a thermal treatment stream for a first period of time, the thermal treatment stream comprising one or more of water (H2O), nitrogen (N2), carbon dioxide (CO2), and argon (Ar); and contacting the catalyst material with a gaseous feed for a second period of time, the gaseous feed comprising ethane (C2H6) and oxygen (O2), to provide an effluent comprising ethylene (C2H4); wherein: at a start of the first period of time the catalyst material comprises an uncalcined catalyst comprising the formula:

MOaVb(Ml)c(M2)dOx wherein:

Mi is Bi, Te, Sb, or a mixture thereof;

19. The method according to claim 18, wherein the first period of time and the second period of time are consecutive.

20. The method according to claim 18, wherein the first period of time and the second period of time overlap.

21. The method according to any one of claims 18 to 20, wherein the thermal treatment stream comprises the water and the water comprises steam.

22. The method according to any one of claims 18 to 21, wherein the thermal treatment stream comprises 20 vol. % to 80 vol.% steam.

23. The method according to claim 22, wherein the thermal treatment stream further comprises 20 vol.% to 80 vol.% nitrogen, carbon dioxide, argon, or any combination thereof.

24. The method according to claim 23, wherein the thermal treatment stream comprises 50 vol.% steam and 50 vol.% nitrogen.

25. The method according to any one of claims 20 to 24, wherein the thermal treatment stream and the gaseous feed comprise, on a combined basis, 5 vol.% to 30 vol.% ethane, 2.5 vol.% to 20 vol.% oxygen, 30 vol.% to 70 vol.% water, and 20 vol.% to 60 vol.% of an inert gas.

26. The method according to any one of claims 18 to 20, wherein the thermal treatment stream comprises the nitrogen.

27. The method according to any one of claims 18 to 26, wherein the contacting of the catalyst material with the thermal treatment stream is at a temperature of 275 °C to 495 °C and a pressure of up to 150 psig.

28. The method according to any one of claims 18 to 26, wherein the contacting of the catalyst material with the thermal treatment stream is at a temperature of 300°C to 450°C.

29. The method according to any one of claims 18 to 28, wherein the contacting of the catalyst material with the gaseous feed is at a temperature of 300°C to 495°C and a pressure of up to 150 psig.

30. The method according to any one of claims 18 to 29, wherein the uncalcined catalyst comprises the formula MoaVbBicTaaOx, MoaVbTecNbdOx, or MoaVbSbcTaaOx.

31. The method according to any one of claims 18 to 30, wherein the uncalcined catalyst comprises the formula Mo1V0.20-0.40Bi0.01-0.07Ta0.01-0.07Ox, Mo1V0.20-0.40Te0.01-0.07Nb0.01-0.07Ox, or Mo1V0.20-0.40Sb0.01-0.07Ta0.01-0.07Ox.

32. The method according to any one of claims 18 to 231, wherein the uncalcined catalyst comprises the formula Mo1V0.31Bi0.05Ta0.05Ox, Mo1V0.30Te0.05 Nbo.o40_x, or Mo1V0.30Sb0.05Ta0.05Ox.

33. The method according to any one of claims 18 to 32, wherein the catalyst material, after the first period of time, has an increased selectivity to one or both of ethylene and acetic acid at equivalent ethane conversion, as compared to the selectivity of the catalyst material at the start of the first period of time.