WO2025215481A1 - Catalyst materials - Google Patents

Abstract

The present disclosure relates to catalyst materials, and to methods for preparing and treating such. An exemplary catalyst includes the formula Mo_aV_b(M₁)_cO_x, wherein M₁ is Bi, Sb, or a mixture thereof, a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral. The catalyst 5 has a powder X-ray diffraction (PXRD) pattern including at least five peaks at 2θ values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Kα radiation. The catalyst is essentially free of tantalum and niobium.

Description

CATALYST MATERIALS

TECHNICAL FIELD

The present disclosure relates to catalysts and catalyst materials for oxidative dehydrogenation (ODH) of alkanes such as ethane, and to methods for preparing and treating same. The catalysts disclosed herein include molybdenum (Mo); vanadium (V); bismuth (Bi) or antimony (Sb), or both; and oxygen (O). The catalysts disclosed herein are made absent niobium and tantalum reagents.

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 can suffer 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 catalyst including the formula: Mo_aVb(Mi)cOx wherein: Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and/or elemental analysis; wherein the catalyst has a powder X-ray diffraction (PXRD) pattern including at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29. 1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation; and wherein the catalyst is essentially free of tantalum and niobium.

The present disclosure also provides a catalyst consisting essentially of the formula: MoaVb(Ml)cOx wherein:

Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis; and wherein the catalyst has a powder X- ray diffraction (PXRD) pattern including at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation.

In some embodiments, the catalyst has the formula Mo1V0.20-0.40Bi0.01-0.07Ox or Mo1V0.20-0.40Sb0.01-0.07Ox. In some embodiments, the catalyst has the formula M01V0.30- 035Bi0.04-0.05Ox or Mo1V0.30-0.35Sb0.04-0.05Ox. In some embodiments, the catalyst has the formula M01Vo.35Bio.05Ox, M01Vo.35Bio.06Ox, M01V0.35 Sbo.osOx, or M01Vo.35Sbo.06Ox.

In some embodiments, the catalyst has a pore volume between 0.02 cm³/g to 0.2 cm³/g as determined by nitrogen physisorption analysis using a Barrett-Joyner-Halenda (BJH) Model. In some embodiments, the catalyst has a Brunauer-Emmett-Teller (BET) surface area between 5 m²/g to 60 m²/g as determined by nitrogen physisorption analysis.

In some embodiments, the catalyst has an ethylene selectivity of at least 75% at an ethane conversion of at least 35% in an oxidative dehydrogenation reaction of ethane.

In some embodiments, the catalyst is prepared by a method that does not include thermal treatment at 500°C or greater.

In some embodiments, the catalyst does not include detectable amounts of niobium (Nb) and tantalum (Ta) when measured using energy-dispersive X-ray spectroscopy.

In some embodiments, the catalyst further includes a molar amount of tellurium, wherein the sum of the molar amount of tellurium, relative to molybdenum, and c is 0.01 to 0.20.

Also provided herein is a catalyst material including a catalyst described herein, and an inert carrier material. In some embodiments, the inert carrier material includes alumina, silica, clay, or any combination thereof. In some embodiments, the catalyst material further includes a lubricant. In some embodiments, the lubricant includes graphite.

Also provided herein is a method for preparing a catalyst including: forming a slurry including metal oxides, one or both of a bismuth compound and an antimony compound, a reducing agent, and water; and heating the slurry to form the catalyst; wherein the metal oxides include: an oxide of molybdenum; and an oxide of vanadium; wherein the bismuth compound includes one or more of bismuth oxide, bismuth hydroxide, or a bismuth carbonate; and wherein the antimony compound includes one or more of an oxide of antimony, an antimony acetate, or an antimony ethoxide; and wherein the catalyst includes the formula: Mo_aVb(Mi)cOx, wherein:

Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; and wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis; and wherein the catalyst has a powder X-ray diffraction (PXRD) pattern comprising at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD patern is obtained using Cu Ka radiation.

In some embodiments of the method, a ratio of the 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 of the method, the bismuth compound is bismuth hydroxide. In some embodiments of the method, the antimony compound is an oxide of antimony.

In some embodiments of the method, the reducing agent includes an alcohol, a carboxylic acid, or an ester. In some embodiments of the method, the reducing agent is oxalic acid. In some embodiments of the method, the slurry includes no more than one reducing agent.

In some embodiments, the method includes heating the slurry 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 catalyst with water.

In some embodiments, the method further includes a thermal treatment of the catalyst at a temperature between 275 °C to 495 °C. In some embodiments of the method, the temperature is between 300°C to 450°C.

In some embodiments of the method, the thermal treatment includes a thermal treatment stream, the thermal treatment stream including one or more of water (H2O), nitrogen (N2), carbon dioxide (CO2), and argon (Ar).

In some embodiments of the method, the catalyst wherein the catalyst has the formula Mo1V0.20-0.40Bi0.01-0.07Ox or Mo1V0.20-0.40Sb0.01-0.07Ox.

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

Also provided herein is a process for the oxidative dehydrogenation of ethane, the process including contacting the catalyst material with a gaseous feed including ethane (C2H6) and oxygen (O2), to provide an effluent including ethylene (C2H4); wherein: the catalyst material includes a catalyst including the formula:

MOaVb(Ml)cOx wherein:

Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis; wherein the catalyst has a powder X-ray diffraction (PXRD) pattern including at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29. 1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation, and wherein the catalyst is essentially free of tantalum and niobium.

A process for the oxidative dehydrogenation of ethane, the process comprising contacting a catalyst material with a gaseous feed comprising ethane (C2H6) and oxygen (O2), to provide an effluent comprising ethylene (C2H4); wherein: the catalyst material comprises a catalyst consisting essentially of the formula: MoaVb(Mi)cOx wherein: Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis; and wherein the catalyst has a powder X-ray diffraction (PXRD) pattern comprising at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation.

In some embodiments, the process includes contacting the 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).

In some embodiments of the process, the first period of time is completed prior to the contacting the catalyst material with the gaseous feed. In some embodiments of the process, the first period of time overlaps with the contacting the catalyst material with the gaseous feed.

In some embodiments of the process, the thermal treatment stream includes the water and the water includes steam. In some embodiments of the process, the thermal treatment stream includes 20 vol% to 80 vol% water.

In some embodiments of the process, the thermal treatment stream further includes 20 vol% to 80 vol% of nitrogen, carbon dioxide, argon, or any combination thereof. In some embodiments of the process, the thermal treatment stream includes nitrogen. In some embodiments of the process, 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, to 20 vol.% to 60 vol.% of an inert gas.

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

In some embodiments of the process, the catalyst includes the formula M01V0.20- o.4oBio.oi-o.o70x or Mo1V0.20-0.40Sb0.01-0.07Ox.

In some embodiments of the process, 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 a powder X-ray diffraction (PXRD) pattern of Catalyst Example Al, described herein.

Figure 2 is a PXRD pattern of the Calcined Subsample of Catalyst Example A2, described herein.

Figure 3 is a PXRD pattern of Catalyst Example B, described herein.

Figure 4 is a PXRD pattern of Catalyst Example C, described herein.

Figure 5 is a PXRD pattern of Comparative Sample A, described herein.

Figure 6 is a PXRD pattern of Comparative Sample B, described herein.

Figure 7 is a flowchart of mass balance method 600 used for analyzing catalyst material performance.

Figure 8 is a graph showing the performance of Catalyst Example Al on stream at an increased flow rate.

Figure 9 is a graph showing the performance of Catalyst Example Al after initial activation at 450°C.

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 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 can lack the long-term stability required for continual operation at industrial process conditions, and/or require one or more calcination steps during catalyst preparation.

The present disclosure relates to catalysts, catalyst materials, and methods for preparing and treating same. The catalysts described herein can demonstrate ethylene selectivity and activity comparable to, or even better than, corresponding catalyst materials containing niobium or tantalum. The catalysts described herein can demonstrate ethylene selectivity and activity comparable to, or even higher than, corresponding catalyst materials containing tantalum or niobium that have 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 preparation. The treatment methods described herein can be carried out in an ODH reactor, eliminating the need for transportation of calcined catalyst materials, which can have lower crush strength as compared to the uncalcined 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 to the disclosed subject matter.

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 statement “one or both 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.

The term “essentially free” as used herein means less than 100 ppm, less than 50 ppm, less than 10 ppm, less than 5 ppm, less than 2 ppm, or less than 1 ppm.

As used herein, the term “oxidative dehydrogenation”, and the abbreviation “ODH”, refers to a process that couples 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. Forming 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 or catalyst material 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 or catalyst material after calcination.

Catalysts

Provided herein is a catalyst including molybdenum (Mo), vanadium (V), Mi, and oxygen (O). Mi includes bismuth (Bi), antimony (Sb), or a mixture thereof. The catalyst is represented by the formula Mo_aVb(Mi)cOx. In some embodiments, the catalyst is essentially free of tantalum and niobium. In some embodiments, the catalyst consists essentially of the formula Mo_aVb(Mi)cOx.

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

The values of a, b, and c may be determined by the amount of each starting material used to form the catalyst and/or elemental analysis.

The values of a, b, and c may refer to the values based on the amount of each starting material used to form the catalyst, such as for example, by the method of preparing a catalyst described later herein. In some embodiments, the values of a, b, and c are determined based on the amount of each starting material used to form the catalyst. For example, the values of a, b, and c are determined based on the amount (molar equivalents) of each Mo, V, and Mi compound used in a hydrothermal synthesis reaction to prepare the catalyst. That is to say that the molar amounts of Mo, V, and Mi used in the synthesis of the catalyst correspond to the values of a, b, and c in the catalyst formula, where b and c are stated relative to the value of a being set to 1.0.

The values of a, b, and c may refer to the 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. The catalyst formula with respect to the ratios of values a, b, and c can be selected to affect the activity, selectivity, purity, and stability of the catalyst.

In some embodiments, the values of a, b, and c are the values measured by EDX.

In some embodiments, b is 0.01 to 0.5. In some embodiments, b is 0.01 to 0.4. In some embodiments, b is 0.01 to 0.3. In some embodiments, b is 0.1 to 0.5. In some embodiments, b is 0.1 to 0.4. In some embodiments, b is 0.1 to 0.3. In some embodiments, b is 0.2 to 0.5. In some embodiments, b is 0.2 to 0.4. In some embodiments, b is 0.20 to 0.35. In some embodiments, b is 0.3 to 0.4. In some embodiments, b is 0.30 to 0.35. In some embodiments, b is 0.25 to 0.35. In some embodiments, b is 0.3. In some embodiments, b is 0.34. In some embodiments, b is 0.35. In some embodiments, b is 0.36.

In some embodiments, c is 0.005 to 0.2. In some embodiments, c is 0.01 to 0.2. In some embodiments, c is 0.01 to 0.1. In some embodiments, c is 0.01 to 0.09. In some embodiments, c is 0.01 to 0.07. In some embodiments, c is 0.02 to 0.1. In some embodiments, c is 0.02 to 0.09. In some embodiments, c is 0.02 to 0.07. In some embodiments, c is 0.03 to 0.1. In some embodiments, c is 0.03 to 0.09. In some embodiments, c is 0.03 to 0.07. In some embodiments, c is 0.04 to 0.07. In some embodiments, c is 0.04 to 0.06. In some embodiments, c is 0.04. In some embodiments, c is 0.05. In some embodiments, c is 0.06.

In some embodiments, the catalyst has the formula Mo1V0.20-0.40Bi0.01-0.07Ox, Mo1V0.20-0.40Sb0.01-0.07Ox, Mo1V0.30-0.35Bi0.04-0.05Ox, or Mo1V0.30-0.35Sb0.04-0.05Ox. In some embodiments, the catalyst has the formula M01Vo.35Bio.05Ox, M01V0.35 Sbo.osOx, M01Vo.35Bio.oeOx, or M01Vo.35Sbo.oeOx.

In some embodiments, the catalyst may further include a molar amount of tellurium (Te). In these embodiments, the catalyst has the formula MoaVb(Mi)ciTe_C2Ox, wherein c2 is the molar amount of tellurium, relative to molybdenum, and wherein the sum of c 1 and c2 is 0.005 to 0.2. In some embodiments, the sum of cl and c2 is 0.01 to 0.1. In some embodiments, the sum of cl and c2 is 0.01 to 0.07. In some embodiments, the sum of cl and c2 is 0.04 to 0.07. In some embodiments, the sum of cl and c2 is 0.05. In some embodiments, the sum of cl and c2 is 0.06.

In some embodiments, the values of a, b, and c are determined by EDX and match the values of a, b, and c determined based on the amount (molar equivalents) in each starting material within 0.05, 0.04, 0.02, or 0.01.

In some embodiments, the catalyst has the formula Mo_aVb(Mi)cOx when measured using EDX. In some embodiments, the catalyst has the formula MoaVbBicOx when measured using EDX. In some embodiments, the catalyst has the formula MoaVbSbcOx when measured using EDX.

The catalyst does not include detectable amounts of niobium (Nb) and tantalum (Ta) when measured using energy-dispersive X-ray spectroscopy (EDX). While the skilled person will appreciate that trace amounts of tantalum and niobium may be present in the metal oxide starting materials used to prepare the catalyst disclosed herein, oxides of tantalum and/or niobium are not deliberately added during catalyst preparation. That is to say the catalyst is prepared absent of niobium- and tantalum-containing reagents. As such, any niobium and tantalum present as a contaminant falls below the detection limit of EDX. In some embodiments, the catalyst includes less than 0.1 wt.%, or less than 0.01 wt.% of niobium and tantalum. In some embodiments, the catalyst is essentially free of niobium and tantalum.

The catalyst has a powder X-ray diffraction (PXRD) pattern including at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29. 1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation.

In some embodiments, the catalyst has a PXRD pattern including at least six, at least seven, at least eight, or at least nine peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation.

In some embodiments, the catalyst has a PXRD pattern including five, six, seven, eight, nine, or ten peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation.

In some embodiments, the catalyst has a PXRD pattern including peaks at 20 values chosen from 12.7 ± 0.2°, 23.3 ± 0.2°, 25.7 ± 0.2°, 27.2 ± 0.2°, and 39.0 ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation. In some embodiments, the PXRD pattern further includes one, two, three, four, or five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 22. 1 ± 0.2°, 28.0 ± 0.2°, and 29. 1 ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation.

In some embodiments, the catalyst has a pore volume between 0.02 cm³/g to 0.2 cm³/g as determined by nitrogen physisorption analysis using a Barrett-Joyner-Halenda (BJH) model. In some embodiments, the catalyst has a pore volume between 0.02 cm³/g to 0.1 cm³/g, 0.04 cm³/g to 0.2 cm³/g, or 0.04 cm³/g to 0.1 cm³/g as determined by nitrogen physisorption analysis using a BJH model. In some embodiments, the catalyst material has a pore volume as determined by nitrogen physisorption analysis with a BJH model from 0.05 cm³/g to 0.2 cm³/g, from 0.05 cm³/g to 0.15 cm³/g, or from 0.05 cm³/g to 0.1 cm³/g. In some embodiments, the catalyst has a pore volume as determined by nitrogen physisorption analysis with a BJH model of 0.02 cm³/g, 0.03 cm³/g, 0.04 cm³/g, 0.05 cm³/g, 0.06 cm³/g, 0.07 cm³/g, 0.08 cm³/g, 0.09 cm³/g, or 0.10 cm³/g.

In some embodiments, a catalyst described herein can have a Brunauer-Emmett- Teller (BET) surface area as determined by nitrogen physisorption analysis before calcination that is 4 times to 50 times greater than the surface area after calcination of the catalyst. In some embodiments, the uncalcined catalyst has a surface area of 20 m²/g to 80 m²/g. In some embodiments, the uncalcined catalyst has a Brunauer-Emmett-Teller (BET) surface area between 5 m²/g to 60 m²/g as determined by nitrogen physisorption analysis. In some embodiments, the uncalcined catalyst has a BET surface area between 5 m²/g to 40 m²/g, 10 m²/g to 60 m²/g, or 10 m²/g to 40 m²/g as determined by nitrogen physisorption analysis.

In some embodiments, the catalyst has the formula Mo1V0.20-0.40Bi0.01-0.07Ox; a powder X-ray diffraction (PXRD) pattern including at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation; a pore volume between 0.02 cm³/g to 0.2 cm³/g as determined by nitrogen physisorption analysis using a Barrett-Joyner-Halenda (BJH) model; and a Brunauer- Emmett-Teller (BET) surface area between 5 m²/g to 60 m²/g as determined by nitrogen physisorption analysis.

In some embodiments, the catalyst has the formula Mo1V0.20-0.40Sb0.01-0.07Ox; a powder X-ray diffraction (PXRD) pattern including at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation; a pore volume between 0.02 cm³/g to 0.2 cm³/g as determined by nitrogen physisorption analysis using a Barrett-Joyner-Halenda (BJH) model; and a Brunauer- Emmett-Teller (BET) surface area between 5 m²/g to 60 m²/g as determined by nitrogen physisorption analysis.

In some embodiments, the catalyst has the formula Mo1V0.30-0.35Bi0.04-0.05Ox; a powder X-ray diffraction (PXRD) pattern including at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation; a pore volume between 0.02 cm³/g to 0.2 cm³/g as determined by nitrogen physisorption analysis using a Barrett-Joyner-Halenda (BJH) model; and a Brunauer- Emmett-Teller (BET) surface area between 5 m²/g to 60 m²/g as determined by nitrogen physisorption analysis.

In some embodiments, the catalyst has the formula Mo1V0.30-0.35Sb0.04-0.05Ox; a powder X-ray diffraction (PXRD) pattern including at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation; a pore volume between 0.02 cm³/g to 0.2 cm³/g as determined by nitrogen physisorption analysis using a Barrett-Joyner-Halenda (BJH) model; and a Brunauer- Emmett-Teller (BET) surface area between 5 m²/g to 60 m²/g as determined by nitrogen physisorption analysis.

In some embodiments, the catalyst has the formula M01Vo.35Bio.05Ox; at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation; a pore volume between 0.02 cm³/g to 0.1 cm³/g, 0.04 cm³/g to 0.2 cm³/g, or 0.04 cm³/g to 0.1 cm³/g as determined by nitrogen physisorption analysis using a Barrett-Joyner-Halenda (BJH) model; and a Brunauer-Emmett-Teller (BET) surface area between 10 m²/g to 40 m²/g as determined by nitrogen physisorption analysis.

In some embodiments, the catalyst has the formula M01Vo.35Sbo.05Ox; at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation; a pore volume between 0.02 cm³/g to 0.1 cm³/g, 0.04 cm³/g to 0.2 cm³/g, or 0.04 cm³/g to 0.1 cm³/g as determined by nitrogen physisorption analysis using a Barrett-Joyner-Halenda (BJH) model; and a Brunauer-Emmett-Teller (BET) surface area between 10 m²/g to 40 m²/g as determined by nitrogen physisorption analysis.

In some embodiments, the catalyst has the formula M01Vo.35Bio.06Ox; at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation; a pore volume between 0.02 cm³/g to 0.1 cm³/g, 0.04 cm³/g to 0.2 cm³/g, or 0.04 cm³/g to 0.1 cm³/g as determined by nitrogen physisorption analysis using a Barrett-Joyner-Halenda (BJH) model; and a Brunauer-Emmet-Teller (BET) surface area between 10 m²/g to 40 m²/g as determined by nitrogen physisorption analysis.

In some embodiments, the catalyst has the formula M01Vo.35Sbo.oeOx; at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation; a pore volume between 0.02 cm³/g to 0.1 cm³/g, 0.04 cm³/g to 0.2 cm³/g, or 0.04 cm³/g to 0.1 cm³/g as determined by nitrogen physisorption analysis using a Barrett-Joyner-Halenda (BJH) model; and a Brunauer-Emmett-Teller (BET) surface area between 10 m²/g to 40 m²/g as determined by nitrogen physisorption analysis.

The catalyst disclosed herein is uncalcined. The catalyst is prepared by a method, disclosed later herein, that does not include a step of thermal treatment at 500°C or greater.

In some embodiments, the catalyst has an ethylene selectivity of at least 75% at an ethane conversion of at least 35% in an oxidative dehydrogenation reaction of ethane. In some embodiments, the catalyst has an ethylene selectivity of at least 76%, at least 77%, at least 78%, at least 79%, at least 80%, at least 81%, at least 82%, at least 83%, at least 84%, or at least 85% at an ethane conversion of at least 35%, at least 40%, at least 45%, or at least 50% in an oxidative dehydrogenation reaction of ethane.

Also provided herein is a catalyst material including a catalyst described herein, and at least one of an inert carrier material, a binder, and a lubricant. In some embodiments, the catalyst material includes 15 wt.% to 99 wt.% of the catalyst. In some embodiments, the catalyst material includes 30 wt.% to 70 wt.% of the catalyst. In some embodiments, the catalyst material includes 40 wt.% to 60 wt.% of the catalyst, such as 50 wt.%.

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 catalyst material includes 1 wt.% to 80 wt.%, 10 wt.% to 70 wt.%, 20 wt.% to 60 wt.%, 30 wt.% to 60 wt.%, or 40 wt.% to 60 wt.% of the inert carrier material. In some embodiments, the catalyst material includes 45 wt. % to 55 wt.%, or 50 wt.% of the inert carrier material.

In some embodiments, the catalyst material includes a lubricant. Non-limiting examples of suitable lubricants include 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. Methods of Preparing a Catalyst

Also provided herein is a method for preparing a catalyst described herein. The method includes forming a slurry including metal oxides, one or both of a bismuth compound and an antimony compound, a reducing agent, and water; and heating the slurry to form the catalyst. The method is performed in the absence of niobium and tantalum reagents. That is, niobium and tantalum oxides are not deliberately and niobium and tantalum would only be present as trace contaminants in other metal oxide reagents. As such, the catalysts prepared by the methods disclosed herein may be considered as essentially free of niobium and tantalum free, and neither niobium nor tantalum are detectable by EDX.

As used herein, the term “slurry” refers to a mixture of solids in a liquid, and includes a suspension, a paste (that is, the mixture is viscous such that it cannot freely move), or a colloidal solution.

The metal oxides include an oxide of molybdenum and an oxide of vanadium. The bismuth compound includes one or more of bismuth oxide, bismuth hydroxide, or a bismuth carbonate, and the antimony compound includes one or more of an oxide of antimony, an antimony acetate, or an antimony ethoxide. As used herein, the term “bismuth carbonate” includes basic carbonates of bismuth and oxide -carbonates (subcarbonates) of bismuth. Examples of a bismuth carbonate include bismuth carbonate basic or bismuth subcarbonate ((BiO^CCh). 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 oxide of molybdenum is MoOs. In some embodiments, the oxide of vanadium is V2O5.

In some embodiments, the bismuth compound is bismuth hydroxide.

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

In some embodiments, a ratio of the water in the slurry to amount of catalyst formed is in a range between 0.1 mb water per gram of catalyst to 10 mL water per gram of catalyst. 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. As used herein, “water” may refer to deionized water, distilled water, and the like. In some embodiments, the water is distilled water. In some embodiments, the water is distilled, deionized water. In some embodiments, the water may include higher levels of contaminants without harming the catalyst.

In some embodiments, a ratio of the water in the slurry to amount of catalyst formed is in a range between 0.1 mL water per gram of catalyst to 5 mL water per gram of catalyst, such as such as between 0.1 mL water per gram of catalyst and 4 mL water per gram of catalyst, between 0. 1 mL water per gram of catalyst and 3 mL water per gram of catalyst, between 0.1 mL water per gram of catalyst and 2 mL water per gram of catalyst, between 0.1 mL water per gram of catalyst and 1 mL water per gram of catalyst, or between 0. 1 mL water per gram of catalyst and 0.5 mL water per gram of catalyst. In some embodiments, the ratio of water in the slurry to amount of catalyst formed is between 0.2 mL water per gram of catalyst and 1 mL water per gram of catalyst. In some embodiments, the ratio of water in the slurry to amount of catalyst formed is between 0.3 mL water per gram of catalyst to 0.5 mL water per gram of catalyst.

Any suitable reducing agent may be included in the slurry. As used herein, the term “reducing agent” refers to a chemical substance that is capable of reducing an oxidation state of one or more of the metals of the metal oxides or the bismuth compound or the antimony compound in the slurry. In some embodiments, the reducing agent includes an alcohol, a carboxylic acid, an ester, or a metal oxide. In some embodiments, the reducing agent is a gaseous reducing agent such as for example, hydrogen, CO, or methane. 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 of the methods disclosed herein, the slurry includes MoOs, V2O5, and Bi(0H)3. In some embodiments, the slurry includes MoO3, V2O5, and Bi(0H)3 in a mass ratio of MoO3:V2C>5:Bi(OH)3 of 1g MoO3 : 0.1 to 0.3 g V2O5 : 0.01g to 0.20 g Bi(OH)3. This mass ratio can be used at any suitable reaction scale. For example, the slurry may include from 4 to 6 g MoO3, from 0.5 g to 1.5 g V2O5, and from 0.05 to 0.2 g Bi(OH)3. In another non-limiting example, the slurry may include from 20 to 25 g MoO3, from 3 to 6 g V2O5, and from 1 to 3 g Bi(OH)3. It will be appreciated that the same mass ratios can be achieved using appropriate amounts of the antimony compound when the catalyst contains antimony. For example, the slurry may include from 20 to 25 g MoO3, from 3 to 6 g V2O5, and from 1 to 3 g Sb2C>3.

For embodiments where the catalyst being prepared further includes tellurium, the slurry further includes an oxide of tellurium, such as TeCh. In some embodiments, the TeCh replaces a portion of the bismuth compound or the antimony compound such that the molar ratio of Mo:V:(Bi+Te) or Mo:V:(Sb+Te) is maintained.

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.

The slurry can be heated by ramping a temperature of the slurry and subsequently holding a temperature of the slurry. The ramping of the temperature can be used to avoid surface boiling of the slurry. The expression “ramping a temperature”, as used herein, refers to changing from an initial temperature to a final temperature over a time. For example, the temperature of the slurry may be ramped from an initial temperature of room temperature to a final temperature greater than room temperature over the course of a specified number of hours. The final temperature may be the holding temperature. The term “room temperature” as used herein refers to a temperature between 15°C and 28°C. The term “holding temperature,” as used herein, refers to the temperature at which the reaction vessel is held, which can be measured by the ambient temperature of the oven the reaction vessel was placed in.

In some embodiments, the method includes heating the slurry by ramping a temperature from ambient to a temperature in a range between 100°C to 200°C over a ramping time between 2 hours to 48 hours, and holding the temperature at a holding temperature in a range between 100°C to 200°C for a holding time between 12 hours to 120 hours. In some embodiments, the method includes ramping the temperature from ambient to a temperature in a range between 100°C to 175°C, 125°C to 200°C, or 125°C to 175°C, over a ramping time between 2 hours to 24 hours, 12 hours to 48 hours, or 12 hours to 24 hours, and holding the temperature at a holding temperature in a range between 100°C to 175°C, 125°C to 200°C, or 125°C to 175°C, for a holding time between 12 hours to 72 hours, 24 hours to 120 hours, or 24 hours to 72 hours.

In some embodiments, the method further includes washing the catalyst with water. For example, in some embodiments, the catalyst is washed with water until the fdtrate is colorless. In some embodiments, the method further comprises a step of drying the catalyst, for example, at temperatures below 100°C. The drying can be done by any suitable method including, for example, at ambient temperature for a suitable time or in an oven overnight at, for example, a temperature of 90°C.

In some embodiments, the method further includes a thermal treatment of the catalyst. In some embodiments, the thermal treatment includes at a temperature of 275°C to 495°C.

In some embodiments, the method includes the thermal treatment after washing the catalyst with water. In some embodiments, the thermal treatment includes contacting the catalyst with a thermal treatment stream including one or more of water (H2O), nitrogen (N2), carbon dioxide (CO2), and argon (Ar). 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.

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 thermal treatment stream includes the water in the form of steam. In some embodiments, the thermal treatment stream includes N2. In some embodiments, the thermal treatment stream is a non-stagnant, flowing stream. In some embodiments, the contacting of the catalyst with the treatment stream is at a temperature of 250°C to 495°C. In some embodiments, the contacting of the catalyst with the treatment stream is at a temperature of 250°C to 470°C, 275°C to 450°C, 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 catalyst with the thermal treatment stream is at a pressure of up to 150 psig, for example, up to 125 psig, or up to 100 psig. In some embodiments, the contacting of the catalyst 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 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 catalyst with the thermal treatment stream is for a time 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. The method for preparing the catalyst does not include a calcination step. That is, the method for preparing the catalyst does not include thermal treatment at 500°C or greater. Alternatively stated, the method is performed at temperatures below 500°C.

In some embodiments, the methods described herein yield a catalyst described herein. For example, in some embodiments, the method yields a catalyst represented by the formula Mo_aVb(Mi)cOx, where a is 1.0, b is 0.01 to 0.5, 0.2 to 0.4, 0.25 to 0.35 or 0.3, and c is 0.005 to 0.2, 0.01 to 0.1, 0.01 to 0.07, 0.04 to 0.07, or 0.05, and x refers to at least the number of oxygen atoms necessary to render the catalyst electrically neutral. In some embodiments, the method yields a catalyst having the formula Mo1V0.20-0.40Bi0.01-0.07Ox, Mo1V0.20-0.40Sb0.01-0.07Ox, Mo1V0.30-0.35Bi0.04-0.05Ox, Mo1V0.30-0.35Sb0.04-0.05Ox, M01Vo.35Bio.05Ox, or M01V0.35 Sbo.osOx, M01Vo.35Bio.oeOx, or M01V0.35 Sbo.oeOx.

The method can provide a catalyst having a PXRD pattern as described elsewhere herein. In some embodiments, the method yields a catalyst having a PXRD pattern including at least five, at least six, at least seven, at least eight, or at least nine peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation. In some embodiments, the method yields a catalyst having a PXRD pattern including peaks at 20 values chosen from 12.7 ± 0.2°, 23.3 ± 0.2°, 25.7 ± 0.2°, 27.2 ± 0.2°, and 39.0 ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation.

The catalyst provided by the method described herein may be combined with one or more of a solid support or carrier, binder, and lubricant, such as the solid supports or carriers, binders, and lubricants disclosed elsewhere herein, to provide a catalyst material. In some embodiments, the catalyst material is prepared by a method that includes preparing an aqueous mixture that includes (i) a catalyst disclosed herein; (ii) a solid support or carrier or inert carrier material; and/or (iii) a lubricant and/or a binder. In some embodiments, the method can further include removing a substantial amount of the water (for example, from 50 wt.% to 99 wt.%) from the aqueous mixture, such as, for example, by heating the mixture at a temperature from 50°C to 100°C. In some embodiments, the method includes forming the catalyst material into a formed catalyst materials such as, for example, a pelleted catalyst material. In some embodiments, the thermal treatment step described earlier herein is performed on the catalyst material, such as the pelleted catalyst material. ODH Methods

The catalysts disclosed herein may be suitable as catalysts in oxidative dehydrogenation (ODH) reactions. The present disclosure further provides a process for the oxidative dehydrogenation of ethane, the method including contacting a catalyst material with a gaseous feed including ethane (C2H5) and oxygen (O2), to provide an effluent including ethylene (C2H4).

The catalyst material can include a catalyst described herein. For example, in some embodiments, the catalyst contacted with the gaseous feed is includes the formula MoaVb(Mi)_cOx, where a, b, and c are as described elsewhere herein, x refers to at least the number of oxygen atoms necessary to render the catalyst electrically neutral, and the catalyst is essentially free of tantalum and niobium. In some embodiments, the catalyst consists essentially of the formula Mo_aVb(Mi)cOx.

In some embodiments, the catalyst contacted with the gaseous feed has the formula Mo1V0.20-0.40Bi0.01-0.07Ox, Mo1V0.20-0.40Sb0.01-0.07Ox, MoiV0.30-0.35Bi0.04-0.05Ox, M01V0.30- o.35Sbo.o4-o.o50x, M01Vo.35Bio.05Ox, MOIVO.35 Sbo.osOx, MoiVo.35Bio.O6Ox, or MoiVo.35Sbo.O6Ox.

In some embodiments of the process, the catalyst contacted with the gaseous feed has a PXRD pattern including at least five, at least six, at least seven, at least eight, or at least nine peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation. In some embodiments of the process, the catalyst contacted with the gaseous feed has a PXRD pattern including peaks at 20 values chosen from 12.7 ± 0.2°, 23.3 ± 0.2°, 25.7 ± 0.2°, 27.2 ± 0.2°, and 39.0 ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation.

In some embodiments, the process further includes contacting the 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). In some embodiments of the process, the first period of time is completed prior to the contacting the catalyst material with the gaseous feed. In some embodiments of the process, the first period of time overlaps with the contacting the catalyst material with the gaseous feed.

In some embodiments of the process, the thermal treatment stream includes the water in the form of steam. In some embodiments of the process, the thermal treatment stream includes 20 vol.% to 80 vol.% steam, 20 vol.% to 60 vol.% steam, 40 vol.% to 80 vol.% steam, or 40 vol.% to 60 vol.% steam. In some embodiments of the process, the thermal treatment stream includes 20 vol.% to 80 vol.%, 20 vol.% to 60 vol.%, 40 vol.% to 80 vol.%, or 40 vol.% to 60 vol.% of nitrogen, carbon dioxide, argon, or any combination thereof. In some embodiments of the thermal process, the thermal treatment stream includes nitrogen. In some embodiments, the thermal treatment stream is 50 vol.% steam and 50 vol.% nitrogen. In some embodiments, the thermal treatment stream is nitrogen.

In some embodiments of the process, the thermal treatment stream and the gaseous feed include, on a combined basis, 5 vol.% to 30 vol.% ethane, 5 vol.% to 20 vol.% ethane, 10 vol.% to 30 vol.% ethane, or 10 vol.% to 20 vol.% ethane. In some embodiments of the process, the thermal treatment stream and the gaseous feed include, on a combined basis, 2.5 vol.% to 20 vol.% oxygen, 2.5 vol.% to 15 vol.% oxygen, 5 vol.% to 20 vol.% oxygen, or 5 vol.% to 15 vol.% oxygen. In some embodiments of the process, the thermal treatment stream and the gaseous feed include, on a combined basis, 30 vol.% to 70 vol.% steam, 30 vol.% to 60 vol.% steam, 40 vol.% to 70 vol.% steam, or 40 vol.% to 60 vol.% steam. In some embodiments of the process, the thermal 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 process, one or both of the contacting of the catalyst material with the thermal treatment stream and the contacting of the catalyst material with the gaseous feed is at a temperature of 275°C to 495°C. In some embodiments, the contacting the catalyst material with the thermal treatment stream and the contacting of the catalyst material with the gaseous feed is at a temperature from 275°C to 450°C, from 300°C to 495°C, from 300°C to 450°C, from 300°C to 470°C, from 350°C to 450°C, from 350°C to 425°C, from 375°C to 425°C, or from 375°C to 400°C.

In some embodiments of the process, one or both of the contacting of the catalyst material with the thermal treatment stream and the contacting of the catalyst material with the gaseous feed is at a pressure of up to 150 psig, up to 100 psig, up to 75 psig, 1 psig to 150 psig, 1 psig to 100 psig, or 1 psig to 75 psig. In some embodiments, one or both of the contacting of the catalyst material with the thermal treatment stream and the contacting of the catalyst material with the gaseous feed is at a pressure from 20 psig to 25 psig.

In some embodiments, the catalyst has a 45% ethane conversion temperature from 300°C to 420°C. In some embodiments, the catalyst has a 45% ethane conversion temperature from 300°C to 400°C. In some embodiments, the catalyst has a 45% ethane conversion temperature from 325°C to 390°C. In some embodiments, the catalyst has a 45% ethane conversion temperature from 340°C to 390°C. In some embodiments, the catalyst has a 45% ethane conversion temperature from 350°C to 400°C. In some embodiments, the catalyst has a 45% ethane conversion temperature from 350°C to 380°C. In some embodiments, the catalyst has a 45% ethane conversion temperature from 360°C to 375°C. As used herein, the phrase “45% ethane conversion temperature” refers to the temperature at which 45% of ethane in a gas stream is converted to a product other than ethane at a given fixed feed composition, weight hourly space velocity, and reactor inlet pressure. The 45% ethane conversion temperature of an oxidative dehydrogenation catalyst can be determined using a microreactor unit (MRU).

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 SWAGEUOK® 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. 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.

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 process, one or both of the contacting of the catalyst material with the thermal treatment stream and the contacting of the catalyst material with the gaseous feed is at a gas hourly space velocity (GHSV) of 1,000 h'¹ to 30,000 h’¹, or 2,000 h'¹ to 5,000 h'¹. In some embodiments of the process, one or both of the contacting of the catalyst material with the thermal treatment stream and the contacting of the catalyst material with the gaseous feed 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 process, one or both of the contacting of the catalyst material with the thermal treatment stream and the contacting of the catalyst material with the gaseous feed is at a linear space velocity of 1 cm/s to 500 cm/s.

In some embodiments of the process, the first period of time is up to 10 hours. In some embodiments, the first period of time is up to 8 hours, up to 6 hours, up to 4 hours, 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 of the process, 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.

Ethylene provided by ODH of ethane using the catalyst, catalyst materials, and processes described herein can subsequently be converted into a variety of products. For example, ethylene can be converted to very low density polyethylene (VLDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), ethylene dichloride, ethylene oxide, ethylbenzene, linear alcohols, vinyl acetate, alkanes, alpha olefins (e.g., 1-hexene and 1-octeene), various hydrocarbon-based fuels, ethanol and the like. These products can then be further processed using methods well known to one of ordinary skill in the art to obtain other valuable chemicals and consumer products.

In some embodiments, ethylene provided by the ODH process described herein is converted to polyethylene. In some embodiments, the polyethylene is very low density polyethylene (VLDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE).

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

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.

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.

EXAMPLES

Equipment and Chemicals

Powder X-ray diffraction (PXRD) experiments were 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.

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 Fisher Scientific Canada. The tantalum pentoxide hydrate (Ta2O5 XH2O; >75% as TaiOs) was purchased from BassTech International. All water used was distilled deionized water. Example 1. Preparation of Catalyst Example Al

Catalyst Example Al 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 mb glass bottle, after which distilled water solvent was used to rinse the grinder and transfer the residual solids to the bottle. The sample was stirred with a PTFE stir bar, yielding an orange slurry. 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 purple-grey hard solid. The sample was scraped from the bottle onto filter paper in a vacuum filtration setup and was washed with distilled water (-300 mL) in portions, to yield a deep blue filtrate. The sample was washed until the filtrate from the sample was nearly colorless, then was dried in an oven at 90°C overnight to yield 26.8753 g of Catalyst Example Al as a purple-grey powdered solid. Analysis by energy dispersive X-ray spectroscopy provided a metal molar ratio of M01Vo.35Bio.06. Table 1. Reagents Used for Hydrothermal Synthesis of Catalyst Example Al Example 2, Preparation of Catalyst Example A2

Catalyst Example A2 was a duplicate synthesis of Catalyst Example Al, prepared with the solid reagents listed in Table 2. 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 mb glass bottle, after which distilled water solvent was used to rinse the grinder and transfer the residual solids to the bottle. The sample was stirred with a PTFE stir bar, yielding an orange slurry. 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 purple-grey hard solid. The sample was scraped from the bottle onto filter paper in a vacuum filtration setup and was washed with distilled water (-300 mL) in portions, to yield a deep blue filtrate. The sample was washed until the filtrate from the sample was nearly colorless, then was dried in an oven at 90°C overnight to yield 26.5731 g of Example A2 as a purple-grey powdered solid.

A subsample of the washed and dried material was 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, and held at 600°C for 2 hours. The furnace was turned off and the samples cooled back to ambient conditions over approximately 12 hours. After calcination, the sample mass was reduced by 2.3% and the solid was a grey powder. Table 2, Reagents Used for Hydrothermal Synthesis of Catalyst Example A2

Example 3 , Preparation of Catalyst Example B

Catalyst Example B was prepared with the solid reagents listed in Table 3. The solid reagents were added to a blender, then the mixture was blended for approximately 3 x 30 s pulses, shaking the container between pulses to ensure good mixing. The solids were then transferred into a 20 mb vial along with the oxalic acid, water and a small stir bar, and the mixture was stirred on a stir plate for approximately 30 minutes, yielding an orange slurry. 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 approximately 6 hours.

The autoclave was then vented in a fume hood and the sample was removed. The hard purple solid was transferred onto filter paper in a Buchner funnel on a vacuum filtration setup. The solid was washed with water until the filtrate was no longer blue, then the solid was dried in an oven at 90°C overnight.

Table 3 , Reagents used for Hydrothermal Synthesis of Catalyst Example B

Example 4, Preparation of Catalyst Example C

Catalyst Example C was prepared with the solid reagents listed in Table 4. The solid reagents were added to a blender and blended for approximately 3 x 30 s pulses, shaking the container between pulses to ensure good mixing. The solids were transferred into a 40 mb vial with a small stir bar, and the water was used to rinse out the blender and transfer to the vial in three portions. The mixture was stirred on a stir plate for 3 minutes until it was a thick orange slurry. The vial was then placed in a 300 mb steel autoclave, water was added around the vial to improve heat transfer and ensure the atmosphere was saturated with steam under reaction temperature, and then the autoclave was sealed. The sealed autoclave was heated in a programmable oven, heating from room temperature to 180°C over 12 hours, the temperature was held at 180°C for 48 hours, then the heating was stopped, and the autoclave was left to cool in the oven passively over approximately 6 hours. The autoclave was vented in a fume hood and the sample was removed. The hard purple solid was transferred onto filter paper in a Buchner funnel on a vacuum filtration setup. The solid was washed with water until the filtrate was no longer blue, then the solid was dried in an oven at 90°C overnight. After drying, powder X-ray diffraction analysis was conducted on the sample.

Table 4, Reagents Used for Hydrothermal Synthesis of Catalyst Example C

Example 5 , Preparation of Comparative Sample A

Comparative Sample A was prepared with the solid reagents listed in Table 5. The solid reagents were added to a 2 L glass beaker, after which 200 mb of the distilled water solvent was added. The solid mixture was then stirred using an overhead stirrer for 5 min at 350 RPM rotation rate to yield an orange slurry. The slurry was then transferred to a glass jar, and the residues were rinsed into the jar with the remaining 20 mb of water. The jar 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 (~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 temperature 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, then 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, and then was transferred to an oven to dry at 90°C for 3 days, to yield 694.14 g of Comparative Sample A, a purple-black solid. Table 5, Reagents Used for Hydrothermal Synthesis of Comparative Sample A

Example 6, Preparation of Comparative Sample B

A subsample of dried Comparative Sample A was taken to calcine under N2 flow. The subsample was heated 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, and held at 600°C for 2 hours. The furnace was turned off and the samples were cooled back to ambient conditions over approximately 12 hours. After calcination, the sample was a deep purpleblack powder. The mass of the solid samples before and after calcining is given in Table 6. Table 6, Mass of Comparative Sample B Before and After Calcination

Example 7, Characterization of Samples

Powder X-ray diffraction (PXRD) analysis was conducted on the samples. By PXRD, Catalyst Example Al was characterized as mixture of a doped molybdenum vanadium oxide phase known as Ml, and molybdenum(VI) oxide (Figure 1). Catalyst Example A2 was characterized as a mixture of molybdenum(VI) oxide and an unidentified second phase (Figure 2). Catalyst Example B was characterized as the Ml phase and molybdenum(VI) oxide (Figure 3). Catalyst Example C was characterized as the Ml phase (Figure 4). Comparative Samples A and B were characterized as doped molybdenum vanadium oxide Ml phases and molybdenum(VI) oxide (Figures 5 and 6, respectively). Nitrogen physisorption analysis was also collected on Catalyst Sample Al. Nitrogen physisorption analysis was collected using a Micromeritics Instruments TriStar gas sorption analyzer. The powdered sample was loaded into a physisorption cell and degassed at 120°C overnight (> 12 h) prior to adsorption measurements. Nitrogen gas sorption analysis was collected at -196°C using 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. The sample was found to have a BET surface area of 19 m²/g and a pore volume of 0.05 cm³/g. Nitrogen physisorption analysis was not collected on the calcined subsample of Catalyst Example A2 as PXRD indicated it no longer contained Ml phase, and catalyst testing showed it was inactive for ethane ODH. Example 8, 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 about 0.4 inches (1.02 cm), and a length of about 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 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 = 3.57 h'¹) and a target inlet pressure of 20 psig. The target gas 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.

For the MRU experiments, the mol% ethane conversion temperature as determined at a WHSV of 3.57 h’¹, and a gas hourly space velocity (GHSV) in the range of 2000 h'¹ to 5000 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 600 shown in Figure 7 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 602, 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 604, 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:

F₀2out = (100000*F_Total*(0.5*Co2) / 22.4)) - 0.5* F2outcthanc - 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* F2outcthanc + ABS(3.5* F2OUTCO2) - 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 606, 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 608, the absolute deviation of estimated and measured O2 in the noncondensable product from the reactor is calculated using Equation 12:

D02 = Co2outcalc - (C021 (CEthane +CEthylne + 0.5*CcO2 + 0.5Cco+ C02) * (1 - CAAoutcalc))

Eq. 12

As shown in step 610, 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 610.

In step 612, ethane conversion is calculated using Equation 13: and selectivity toward each product is calculated using Equation 14: wherein CxoutCalc ^— CEthyleneoutCalc, CAAoutCalc, 0.5 * Cc02outCalc Or 0.5 * CcOOutcalc .

Performance - Catalyst Samples A and B

Testing of Catalyst Examples Al and Calcined A2 (Table 8) offered a comparison of the same catalyst without any calcination step (Catalyst Example Al) or with one thermal treatment at 600°C under nitrogen flow (calcined subsample of Catalyst Example A2). Catalyst Example Al was 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 2 hours. Afterwards the sample was brought back to the same process conditions as before the treatment and left on stream to equilibrate. The calcined subsample of Catalyst Example A2 was inactive for ethane ODH; the minor amount of ethane conversion was attributed to gas phase reactions of ethane and oxygen in the process stream.

Table 8, Comparison of Catalyst Example Al and Calcined Subsampled of Catalyst

Example A2

The results showed that tantalum and niobium -free Catalyst Example Al was highly active for ethane ODH, and treatment of the catalyst with steam in the reactor further increased both activity and selectivity of the catalyst to valuable ethylene and acetic acid products. At only 300°C under these conditions, the catalyst was allowing for nearly full consumption of oxygen in the reaction, with oxygen conversion of 97. 1%. Compared to Comparative Samples A and B (discussed below), Catalyst Example Al was more active with equivalent to better selectivity than both samples. The steam treatment of Catalyst Example Al also showed that the catalyst was stable to at least 400°C, which gave at least 100°C buffer in the case of thermal runaway. The data also showed that Catalyst Example A2 decomposed to an ODH inactive catalyst after calcination at 600°C under nitrogen flow.

Performance - Comparative Samples A and B

Testing of Comparative Samples A and B (Table 9) offered a comparison to a tantalum doped MoVTaBiOx-type catalyst without any calcination step (Comparative Sample A) or with one thermal treatment at 600°C under nitrogen flow (Comparative Sample B). Both samples were also treated with 150 seem flow (WHSV = 1.79h^-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.

Table 9, Comparison of Comparative Samples A and B

The results showed that the tantalum doped Comparative Samples were active and selective for ethane ODH to ethylene, but were less active and less selective to ethylene and acetic acid than Catalyst Sample A after steam treatment in the reactor.

Performance - Catalyst Example Al

Data was collected for about one week on stream for Catalyst Example Al after steam treatment on stream. This longer term run data was collected by first doubling the gas flow rates in the reactor to a total flow of 307 seem (WHSV ~ 3.6 h'¹). This increase in flow rate allowed for an increase in the reactor temperature to 350° C without entering an oxygen- depleted atmosphere due to the high activity of the sample. The reactor temperature was held at 350°C, and data was taken periodically over an 8 day period to test the longer-term stability of the catalyst under higher-temperature conditions. As shown in Figure 8, the results indicate a steady degradation in catalyst activity over the 8 day period on stream.

Next, a fresh batch of Catalyst Example Al was loaded and left on stream at 300°C for 65 hours prior to treatment. After the initial time on stream, selectivity of the sample to value-added products increased substantially, with no significant loss in activity. The catalyst sample was treated under a pure nitrogen stream (150 seem flow; WHSV = 1.79 h" ') for 2 hours at 450°C. After this treatment, the sample was cooled back to 300°C and the process gas flow was restarted (20/10/70 ethane/oxygen/nitrogen; 153 seem flow rate). After the nitrogen treatment, the activity had decreased, but the selectivity to value added products increased. The sample was then heated to 350°C and held at that temperature for 257 hours, and the performance of the catalyst — both activity and selectivity — improved over time. The data before and after the treatment under N2 flow is given in Table 10, below.

Table 10. Catalyst Example A

Samples were taken periodically over the 257 hours on stream at 350°C. As shown in Figure 9, the data shows that the catalyst performance remained stable after an initial activation period.

Performance - Catalyst Examples B and C

Catalyst Examples B and C were tested for catalyst performance using the MRU as described for Catalyst A. For each, 2 g of catalyst phase was placed in the reactor and both were pretreated under 153 seem N2 flow at 450°C for 2 hours before testing began. Data from the testing is shown in Table 11. The data demonstrates that both the MoVaBibTecOx and MoVaSbbOx catalyst phases are highly active and selective for ethane ODH. Catalyst Example B was run for 284 hours on stream with no loss in performance before test completion, while Catalyst Example C was run for 140 hours on stream with no loss in performance before test completion.

Table 11. Catalyst Example B and C

Non-limiting embodiments of the present disclosure include the following:

Embodiment A: A catalyst comprising the formula: Mo_aVb(Mi)cOx, wherein: Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis; wherein the catalyst has a powder X-ray diffraction (PXRD) pattern comprising at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation; and wherein the catalyst is essentially free of tantalum and niobium.

Embodiment B: A catalyst consisting essentially of the formula: Mo_aVb(Mi)cOx, wherein: Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis; and wherein the catalyst has a powder X- ray diffraction (PXRD) pattern comprising at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation. Embodiment C: The catalyst of Embodiment A or B, having the formula M01V0.20- o.4oBio.oi-o.o70x or Mo1V0.20-0.40Sb0.01-0.07Ox.

Embodiment D: The catalyst of Embodiment A or B, having the formula M01V0.30- o.35Bio.o4-o.oeOx or Mo1V0.30-0.35Sb0.04-0.0eOx.

Embodiment E: The catalyst of Embodiment A or B, having the formula M01Vo.35Bio.05Ox, M01Vo.35Bio.oeOx, M01Vo.35Sbo.05Ox, or M01Vo.35Sbo.oeOx.

Embodiment F: The catalyst of Embodiment A, B, C, D, or E, having a pore volume between about 0.02 cm³/g to about 0.2 cm³/g as determined by nitrogen physisorption analysis using a Barrett-Joyner-Halenda (BJH) model.

Embodiment G: The catalyst of Embodiment A, B, C, D, E, or F, having a Brunauer-Emmett-Teller (BET) surface area between about 5 m²/g to about 60 m²/g as determined by nitrogen physisorption analysis.

Embodiment H. The catalyst of Embodiment A, B, C, D, E, F, or G, having an ethylene selectivity of at least about 75% at an ethane conversion of at least about 35% in an oxidative dehydrogenation reaction of ethane.

Embodiment E The catalyst of Embodiment A, B, C, D, E, F, G, or H, prepared by a method that does not comprise thermal treatment at 500°C or greater.

Embodiment J. The catalyst of Embodiment A, B, C, D, E, F, G, H, or I, wherein the catalyst does not comprise detectable amounts of niobium (Nb) and tantalum (Ta) when measured using energy-dispersive X-ray spectroscopy.

Embodiment K. The catalyst Embodiment A, further comprising a molar amount of tellurium (Te), wherein the sum of the amount of tellurium and c is about 0.01 to about 0.20.

Embodiment L. A catalyst material comprising the catalyst of Embodiment A, B, C, D, E, F, G, H, I, J, or K and an inert carrier material.

Embodiment M. The catalyst material of Embodiment L, wherein the inert carrier material comprises alumina, silica, clay, or any combination thereof.

Embodiment N. The catalyst material of Embodiment L or M, further comprising a lubricant.

Embodiment O. A method for preparing a catalyst comprising: forming a slurry comprising metal oxides, one or both of a bismuth compound and an antimony compound, a reducing agent, and water; and heating the slurry to form the catalyst; wherein the metal oxides comprise: an oxide of molybdenum; and an oxide of vanadium; wherein the bismuth compound comprises one or more of bismuth oxide, bismuth hydroxide, or a bismuth carbonate; wherein the antimony compound comprises one or more of an oxide of antimony, an antimony acetate, or an antimony ethoxide; and wherein the catalyst comprises the formula Mo_aVb(Mi)cOx, wherein: Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; and wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis; wherein the catalyst has a powder X-ray diffraction (PXRD) pattern comprising at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation; and wherein the catalyst is essentially free of tantalum and niobium.

Embodiment P. The method according to Embodiment O, wherein a ratio of the water in the slurry to amount of catalyst formed is in a range between about 0.1 mb water per gram of catalyst to about 10 mb water per gram of catalyst.

Embodiment Q. The method according to Embodiment O or P, wherein the bismuth compound is bismuth hydroxide.

Embodiment R. The method according to Embodiment O, P, or Q, wherein the antimony compound is an oxide of antimony.

Embodiment S. The method according to Embodiment O, P, Q, or R, wherein the reducing agent comprises an alcohol, a carboxylic acid, or an ester.

Embodiment T. The method according to Embodiment S, wherein the reducing agent is oxalic acid.

Embodiment U. The method according to Embodiment O, P, Q, R, S, or T, wherein the slurry comprises no more than one reducing agent.

Embodiment V. The method according to Embodiment O, P, Q, R, S, T, or U, comprising heating the slurry by: ramping a temperature from ambient to a temperature in a range between about 100°C to about 200°C over a ramping time between about 2 hours to about 48 hours; and holding the temperature at a holding temperature in a range between about 100°C to about 200°C for a holding time between about 12 hours to about 120 hours.

Embodiment W. The method according to Embodiment O, P, Q, R, S, T, U, or V, performed in the absence of niobium and tantalum reagents.

Embodiment X. The method according to Embodiment O, P, Q, R, S, T, U, V, W, or W, further comprising a thermal treatment of the catalyst at a temperature between about 275°C to about 495°C. Embodiment Y. The method according Embodiment X, wherein the temperature is between about 300°C to about 450°C.

Embodiment Z. The method according to Embodiment X or Y, wherein the thermal treatment comprises contacting the catalyst with a thermal treatment stream, the thermal treatment stream comprising one or more of water (H2O), nitrogen (N2), carbon dioxide (CO2), and argon (Ar).

Embodiment AA. The method according to Embodiment O, P, Q, R, S, T, U, V, W, X, Y, or Z, wherein the catalyst has the formula Mo1V0.20-0.40Bi0.01-0.07Ox or M01V0.20-

O.4oSbo.01-0.070x.

Embodiment AB. The method according to Embodiment O, wherein the slurry further comprises an oxide of tellurium.

Embodiment AC. A catalyst, prepared by the method according to Embodiment O,

P, Q, R, S, T, U, V, W, X, Y, Z, AA, or AB.

Embodiment AD. A process for the oxidative dehydrogenation of ethane, the process comprising contacting a catalyst material with a gaseous feed comprising ethane (C2H6) and oxygen (O2), to provide an effluent comprising ethylene (C2H4); wherein: the catalyst material comprises a catalyst comprising the formula: Mo_aVb(Mi)cOx wherein: Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis; wherein the catalyst has a powder X-ray diffraction (PXRD) pattern comprising at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation; and wherein the catalyst is essentially free of tantalum and niobium.

Embodiment AE. A process for the oxidative dehydrogenation of ethane, the process comprising contacting a catalyst material with a gaseous feed comprising ethane (C2H6) and oxygen (O2), to provide an effluent comprising ethylene (C2H4); wherein: the catalyst material comprises a catalyst consisting essentially of the formula: MoaVb(Mi)cOx wherein: Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis; and wherein the catalyst has a powder X-ray diffraction (PXRD) pattern comprising at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD patern is obtained using Cu Ka radiation.

Embodiment AF. The process according to Embodiment AD or AE, further comprising contacting the 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).

Embodiment AG. The process according to Embodiment AF, wherein the first period of time is completed prior to the contacting the catalyst material with the gaseous feed.

Embodiment AH. The process according to Embodiment AF, wherein the first period of time overlaps with the contacting the catalyst material with the gaseous feed.

Embodiment Al. The process according to Embodiment AF, AG, or AH, wherein the thermal treatment stream comprises the water and the water comprises steam.

Embodiment AJ. The process according to Embodiment Al, wherein the thermal treatment stream comprises about 20 vol.% to about 80 vol.% water.

Embodiment AK. The process according to Embodiment Al or AJ, wherein the thermal treatment stream further comprises about 20 vol.% to about 80 vol.% of nitrogen, carbon dioxide, argon, or any combination thereof.

Embodiment AL. The process according to Embodiment AF, wherein the thermal treatment stream comprises nitrogen.

Embodiment AM. The process according to Embodiment AF, AG, AH, Al, AJ, AK, or AL, wherein the thermal treatment stream and the gaseous feed comprise, on a combined basis, about 5 vol.% to about 30 vol.% ethane, about 2.5 vol.% to about 20 vol.% oxygen, about 30 vol.% to about 70 vol.% water, and about 20 vol.% to about 60 vol.% of an inert gas.

Embodiment AN. The process according to Embodiment AF, AG, AH, Al, AJ, AK, AL, or AM, wherein one or both of the contacting of the catalyst material with the thermal treatment stream and the contacting of the catalyst material with the gaseous feed is at a temperature of about 275 °C to about 495 °C and a pressure of up to about 150 psig.

Embodiment AO. The process according to Embodiment AF, AG, AH, Al, AJ, AK, AL, AM, or AN, wherein one or both of contacting of the catalyst material with the thermal treatment stream and the contacting of the catalyst material with the gaseous feed is at a temperature of about 300°C to about 450°C and a pressure of up to about 150 psig. Embodiment AP. The process according to Embodiment AE, AF, AG, AH, Al, AJ, AK, AL, AM, AN, or AO, wherein the catalyst has the formula Mo1V0.20-0.40Bi0.01-0.07Ox or Mo1V0.20-0.40Sb0.01-0.07Ox.

Embodiment AQ. The process according to Embodiment AF, AG, AH, Al, AJ, AK, AL, AM, AN, AO, or AP, 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

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

Claims

1. A catalyst comprising the formula: OaVb( l)cOx wherein:

Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis; wherein the catalyst has a powder X-ray diffraction (PXRD) pattern comprising at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation; and wherein the catalyst is essentially free of tantalum and niobium.

2. A catalyst consisting essentially of the formula:

MoaVb(Ml)cOx wherein:

Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis; and wherein the catalyst has a powder X-ray diffraction (PXRD) pattern comprising at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation.

3. The catalyst of claim 1 or 2, wherein the catalyst has the formula Mo1V0.20-0.40Bi0.01- o.o?Ox or Mo1V0.20-0.40Sb0.01-0.07Ox.

4. The catalyst of claim 1 or 2, wherein the catalyst as the formula Mo1V0.30-0.35Bi0.04- o.oeOx or Mo1V0.30-0.35Sb0.04-0.60Ox.

5. The catalyst of claim 1 or 2, wherein the catalyst has the formula M01Vo.35Bio.05Ox, M01Vo.35Bio.oeOx, M01V0.35 Sbo.osOx, or M01Vo.35Sbo.oeOx.

6. The catalyst of any one of claims 1 to 5, having a pore volume between 0.02 cm³/g to 0.2 cm³/g as determined by nitrogen physisorption analysis using a Barrett- Joyner- Halenda (BJH) model.

7. The catalyst of any one of claims 1 to 6, having a Brunauer-Emmett-Teller (BET) surface area between 5 m²/g to 60 m²/g as determined by nitrogen physisorption analysis.

8. The catalyst of any one of claims 1 to 7, having an ethylene selectivity of at least 75% at an ethane conversion of at least 35% in an oxidative dehydrogenation reaction of ethane.

9. The catalyst of any one of claims 1 to 8, prepared by a method that does not comprise thermal treatment at 500°C or greater.

10. The catalyst of any one of claims 2 to 8, wherein the catalyst does not comprise detectable amounts of niobium (Nb) and tantalum (Ta) when measured using energy- dispersive X-ray spectroscopy.

11. The catalyst of claim 1 or 2, further comprising a molar amount of tellurium, wherein the sum of the molar amount of tellurium, relative to molybdenum, and c is 0.01 to 0.20.

12. A catalyst material comprising the catalyst of any one of claims 1 to 11, and an inert carrier material.

13. The catalyst material of claim 12, wherein the inert carrier material comprises alumina, silica, clay, or any combination thereof.

14. The catalyst material of claim 12 or claim 13, further comprising a lubricant.

15. A method for preparing a catalyst comprising : forming a slurry comprising metal oxides, one or both of a bismuth compound and an antimony compound, a reducing agent, and water; and heating the slurry to form the catalyst; wherein the metal oxides comprise: an oxide of molybdenum; and an oxide of vanadium; wherein the bismuth compound comprises on or more of bismuth oxide, bismuth hydroxide, or a bismuth carbonate; wherein the antimony compound comprises one or more of an oxide of antimony, an antimony acetate, or an antimony ethoxide; and wherein the catalyst comprises the formula: MOaVb(Ml)cOx, wherein:

Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis; wherein the catalyst has a powder X-ray diffraction (PXRD) pattern comprising at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation; and wherein the catalyst is essentially free of tantalum and niobium.

16. The method according to claim 15, wherein a ratio of the 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.

17. The method according to claim 15 or 16, wherein the bismuth compound is bismuth hydroxide.

18. The method according to any one of claims 15 to 17, wherein the antimony compound is an oxide of antimony.

19. The method according to any one of claims 15 to 18, wherein the reducing agent comprises an alcohol, a carboxylic acid, or an ester.

20. The method according to claim 19, wherein the reducing agent is oxalic acid.

21. The method according to any one of claims 15 to 20, wherein the slurry comprises no more than one reducing agent.

22. The method according to any one of claims 15 to 21, comprising heating the slurry by: ramping a temperature from ambient to a temperature in a range between 100°C to 200°C over a ramping time between 2 hours to 48 hours; and holding the temperature at a holding temperature in a range between 100°C to 200°C for a holding time between 12 hours to 120 hours.

23. The method according to any one of claims 15 to 22, performed in the absence of niobium and tantalum reagents.

24. The method according to any one of claims 15 to 23, further comprising a thermal treatment of the catalyst at a temperature between 275 °C to 495 °C.

25. The method according to claim 24, wherein the temperature is between 300°C to 450°C.

26. The method according to claim 24 or 25, wherein the thermal treatment comprises contacting the catalyst with a thermal treatment stream, the thermal treatment stream comprising one or more of water (H2O), nitrogen (N2), carbon dioxide (CO2), and argon (Ar).

27. The method according to any one of claims 15 to 26, wherein the catalyst has the formula Mo1V0.20-0.40Bi0.01-0.07Ox or Mo1V0.20-0.40Sb0.01-0.07Ox.

28. The method according to claim 15, wherein the slurry further comprises an oxide of tellurium.

29. A catalyst, prepared by the method according to any one of claims 15 to 28.

30. A process for the oxidative dehydrogenation of ethane, the process comprising contacting a catalyst material with a gaseous feed comprising ethane (C2H6) and oxygen (O2), to provide an effluent comprising ethylene (C2H4); wherein: the catalyst material comprises a catalyst comprising the formula: MOaVb(Ml)cOx wherein:

Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis; wherein the catalyst has a powder X-ray diffraction (PXRD) pattern comprising at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°,

23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD patern is obtained using Cu Ka radiation; and wherein the catalyst is essentially free of tantalum and niobium.

31. A process for the oxidative dehydrogenation of ethane, the process comprising contacting a catalyst material with a gaseous feed comprising ethane (C2H6) and oxygen (O2), to provide an effluent comprising ethylene (C2H4); wherein: the catalyst material comprises a catalyst consisting essentially of the formula: MOaVb(Ml)cOx wherein:

Mi is Bi, Sb, or a mixture thereof; a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is at least the number of oxygen atoms necessary to render the catalyst electrically neutral; wherein a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis; and wherein the catalyst has a powder X-ray diffraction (PXRD) patern comprising at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29.1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD patern is obtained using Cu Ka radiation.

32. The process according to claim 30 or 31, further comprising contacting the 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).

33. The process according to claim 32, wherein the first period of time is completed prior to the contacting the catalyst material with the gaseous feed.

34. The process according to claim 32, wherein the first period of time overlaps with the contacting the catalyst material with the gaseous feed.

35. The process according to any one of claims 32 to 34, wherein the thermal treatment stream comprises the water and the water comprises steam.

36. The process according to claim 35, wherein the thermal treatment stream comprises 20 vol. % to 80 vol.% steam.

37. The process according to claim 35 or 36, wherein the thermal treatment stream further comprises 20 vol.% to 80 vol.% of nitrogen, carbon dioxide, argon, or any combination thereof.

38. The process according to claim 32, wherein the thermal treatment stream comprises nitrogen.

39. The process according to any one of claims 32 to 38, 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.

40. The process according to any one of claims 32 to 39, wherein one or both of the contacting of the catalyst material with the thermal treatment stream and the contacting of the catalyst material with the gaseous feed is at a temperature of 15 °C to 495 °C and a pressure of up to 150 psig.

41. The process according to any one of claims 32 to 40, wherein one or both of contacting of the catalyst material with the thermal treatment stream and the contacting of the catalyst material with the gaseous feed is at a temperature of 300°C to 450°C and a pressure of up to 150 psig.

42. The process according to any one of claims 30 to 41, wherein the catalyst has the formula Mo1V0.20-0.40Bi0.01-0.07Ox or Mo1V0.20-0.40Sb0.01-0.07Ox.

43. The process according to any one of claims 32 to 43, 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.