Systems and methods to alter ethylene or acetic acid selectivity using reactor space velocity

Abstract

The disclosure relates to systems and methods to alter the ethylene and / or acetic acid selectivity in the catalytic oxidative dehydrogenation of ethane using reactor space velocity.

Description

[0001] SYSTEMS AND METHODS TO ALTER ETHYLENE OR ACETIC ACID SELECTIVITY USING REACTOR SPACE VELOCITY

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 585,390, filed September 26, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0004] TECHNICAL FIELD

[0005] The disclosure relates to systems and methods to alter the ethylene and / or acetic acid selectivity in the catalytic oxidative dehydrogenation of ethane using reactor space velocity.

[0006] BACKGROUND ART

[0007] 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. The method of choice for today's 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 produce 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.

[0008] 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 or nitrogen or steam, which may be performed at temperatures as low as 300°C, to produce the corresponding alkene. Various other oxidation products may be produced in this process, including acetic acid, carbon dioxide (CO2) and carbon monoxide (CO). ODH suffers from relatively lower conversion rates when compared to steam cracking. SUMMARY OF INVENTION

[0009] The disclosure relates to systems and methods to alter the ethylene and / or acetic acid selectivity in the catalytic oxidative dehydrogenation of ethane using reactor space velocity.

[0010] In a first aspect, the disclosure provides a method, including: selecting a first product from the group consisting of ethylene and acetic acid, selecting a gas hourly space velocity (GHSV) or linear velocity, contacting a feed stream including ethane and oxygen with a catalyst at the selected GHSV or linear velocity, and converting at least a portion of the ethane into the first product. The catalyst includes a catalyst with the formula MoaVbTecTadOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral; MoaVbSbcTaaOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral; MoaVbTecNbdOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral; or MoaVbBicTaaOx; wherein a is about 1.0; b is about 0.01 to about 0.5; c is about 0.005 to about 0.2; d is about 0.005 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0011] In some embodiments, the first product is ethylene and the GHSV is greater than about 9000 h’1. In some embodiments, the first product is acetic acid, and the GHSV is less than about 9000 h’1. In some embodiments, the first product is ethylene and the GHSV is greater than about 9500 h’1. In some embodiments, the first product is acetic acid and the GHSV is less than about 9500 h’1. In some embodiments, the first product is ethylene and the linear velocity is greater than about 45 cm / sec. In some embodiments, the first product is acetic acid and the GHSV is less than about 45 cm / sec. In some embodiments, the first product is ethylene and the GHSV is greater than about 15000 h’1. In some embodiments, the first product is acetic acid and the GHSV is less than about 15000 h’1. In some embodiments, the first product is ethylene and the linear velocity is greater than about 80 cm / sec. In some embodiments, the first product is acetic acid and the linear velocity is less than about 80 cm / sec.

[0012] In some embodiments, the first product is acetic acid, the catalyst includes a catalyst with the formula MoaVbTecTaaOx, the GHSV is about 4776 h’1, a selectivity for ethylene is less than about 75 %, and a selectivity for acetic acid is greater than about 10 %. In some embodiments, the first product is ethylene, the catalyst includes a catalyst with the formula MoaVbTecTaaOx, the GHSV is about 14144 h’1, a selectivity for ethylene is greater than about 70 %, and a selectivity for acetic acid is less than about 20 %. In some embodiments, the first product is acetic acid, the catalyst includes a catalyst with the formula MoaVbTecTaaOx, the linear velocity is about 23 cm / sec, a selectivity for ethylene is less than about 75 %, and a selectivity for acetic acid is greater than about 10 %. In some embodiments, the first product is ethylene, the catalyst includes a catalyst with the formula MoaVbTecTaaOx, the linear velocity is about 67 cm / sec, a selectivity for ethylene is greater than about 70 %, and a selectivity for acetic acid is less than about 20 %.

[0013] In some embodiments, the first product is acetic acid, the catalyst includes a catalyst with the formula MoaVbBicTaaOx, the GHSV is about 4714 h’1, a selectivity for ethylene is less than about 90 %, and a selectivity for acetic acid is greater than about 0 %. In some embodiments, the first product is ethylene, the catalyst includes a catalyst with the formula MoaVbBicTaaOx, the GHSV is about 28266 h’1, a selectivity for ethylene is greater than about 85 %, and a selectivity for acetic acid is less than about 10 %. In some embodiments, the first product is acetic acid, the catalyst includes a catalyst with the formula MoaVbBicTaaOx, the linear velocity is about 22 cm / sec, a selectivity for ethylene is less than about 80 %, and a selectivity for acetic acid is greater than about 0 %. In some embodiments, the first product is ethylene, the catalyst includes a catalyst with the formula MoaVbBicTaaOx, the linear velocity is about 136 cm / sec, a selectivity for ethylene is greater than about 85 %, and a selectivity for acetic acid is less than about 10 %.

[0014] In some embodiments, the catalyst includes a catalyst with the formula MoaVbTecTaaOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral; or MoaVbBicTaaOx; wherein a is about 1.0; b is about 0.01 to about 0.5; c is about 0.005 to about 0.2; d is about 0.005 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0015] In some embodiments, the catalyst includes a catalyst with the formula MoaVbTecTaaOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0016] In some embodiments, the catalyst includes a catalyst with the formula MoaVbBicTaaOx; wherein a is about 1.0; b is about 0.01 to about 0.5; c is about 0.005 to about 0.2; d is about 0.005 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral. In a second aspect, the disclosure provides a method, including: contacting a first feed stream including ethane and oxygen with a catalyst at a first gas hourly space velocity (GHSV) or linear velocity, converting at least a portion of the ethane into a first product, contacting a second feed stream including ethane and oxygen with the catalyst at a second GHSV or linear velocity, and converting at least a portion of the ethane into a second product. The second GHSV or linear velocity is different from the first GHSV or linear velocity. The first product and second product are independently selected from the group consisting of ethylene and acetic acid and the second product is different from the first product. The catalyst includes a catalyst with the formula MoaVbTecTadOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral; MoaVbSbcTaaOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral; MoaVbTecNbaOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral; or MoaVbBicTadOx; wherein a is about 1.0; b is about 0.01 to about 0.5; c is about 0.005 to about 0.2; d is about 0.005 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0017] In some embodiments, the catalyst has a higher selectivity for the first product at the first GHSV or linear velocity relative to the second GHSV or linear velocity, and the catalyst has a higher selectivity for the second product at the second GHSV or linear velocity relative to the first GHSV or linear velocity.

[0018] In some embodiments, the first GHSV or linear velocity is higher than the second GHSV or linear velocity, the first product includes ethylene, and the second product includes acetic acid. In some embodiments, the first GHSV or linear velocity is lower than the second GHSV or linear velocity, the first product includes acetic acid, and the second product includes ethylene.

[0019] In some embodiments, the first product is ethylene, the first GHSV is greater than about 9000 h’1, the second product is acetic acid, and the second GHSV is less than about 9000 h’1. In some embodiments, the first product is acetic acid, the first GHSV is less than about 9000 h’1, the second product is ethylene, and the second GHSV is greater than about 9000 h’1. In some embodiments, the first product is ethylene, the first linear velocity is greater than about 45 cm / sec, the second product is acetic acid, and the second linear velocity is less than about 45 cm / sec. In some embodiments, the first product is acetic acid, the first linear velocity is less than about 45 cm / sec, the second product is ethylene, and the second linear velocity is greater than about 45 cm / sec. In some embodiments, the first product is ethylene, the first GHSV is greater than about 15000 h’1, the second product is acetic acid, and the second GHSV is less than about 15000 h'1. In some embodiments, the first product is acetic acid, the first GHSV is less than about 15000 h’1, the second product is ethylene, and the second GHSV is greater than about 15000 h'1. In some embodiments, the first product is ethylene, the first linear velocity is greater than about 80 cm / sec, the second product is acetic acid, and the second linear velocity is less than about 80 cm / sec. In some embodiments, the first product is acetic acid, the first linear velocity is less than about 80 cm / sec, the second product is ethylene, and the second linear velocity is greater than about 80 cm / sec.

[0020] In some embodiments, the catalyst includes a catalyst with the formula MoaVbTecTadOx; the first product is ethylene and the second product is acetic acid; the first GHSV is about 14144 h’1; at the first GHSV a selectivity for ethylene is greater than about 70 %, and a selectivity for acetic acid is less than about 20 %; the second GHSV is about 4776 h’1; and at the second GHSV a selectivity for ethylene is less than about 75 %, and a selectivity for acetic acid is greater than about 10 %.

[0021] In some embodiments, the catalyst includes a catalyst with the formula MoaVbTecTadOx; the first product is acetic acid and the second product is ethylene; the first GHSV is about 4776 h’1; at the first GHSV a selectivity for ethylene is less than about 75 %, and a selectivity for acetic acid is greater than about 10 %; the second GHSV is about 14144 h’1; and at the second GHSV a selectivity for ethylene is greater than about 70 %, and a selectivity for acetic acid is less than about 20 %.

[0022] In some embodiments, the catalyst includes a catalyst with the formula MoaVbTecTadOx; the first product is ethylene and the second product is acetic acid; the first linear velocity is about 67 cm / sec; at the first linear velocity a selectivity for ethylene is greater than about 70 %, and a selectivity for acetic acid is less than about 20 %; the second linear velocity is about 23 cm / sec; and at the second linear velocity a selectivity for ethylene is less than about 75 %; and a selectivity for acetic acid is greater than about 10 %.

[0023] In some embodiments, the catalyst includes a catalyst with the formula MoaVbTecTadOx; the first product is acetic acid and the second product is ethylene; the first linear velocity is about 23 cm / sec; at the first linear velocity a selectivity for ethylene is less than about 75 %, and a selectivity for acetic acid is greater than about 10 %; the second linear velocity is about 67 cm / sec; and at the second linear velocity a selectivity for ethylene is greater than about 70 %, and a selectivity for acetic acid is less than about 20 %. In some embodiments, the catalyst includes a catalyst with the formula MoaVbBicTaaOx; the first product is ethylene and the second product is acetic acid; the first GHSV is about 28266 h’1; at the first GHSV a selectivity for ethylene is greater than about 85 %, and a selectivity for acetic acid is less than about 10 %; the second GHSV is about 4714 h’1; and at the second GHSV a selectivity for ethylene is less than about 90 %, and a selectivity for acetic acid is greater than about 0 %.

[0024] In some embodiments, the catalyst includes a catalyst with the formula MoaVbBicTadOx; the first product is acetic acid and the second product is ethylene; the first GHSV is about 4714 h’1; at the first GHSV a selectivity for ethylene is less than about 90 %, and a selectivity for acetic acid is greater than about 0 %; the second GHSV is about 28266 h’1; and at the second GHSV a selectivity for ethylene is greater than about 85 %, and a selectivity for acetic acid is less than about 10 %.

[0025] In some embodiments, the catalyst includes a catalyst with the formula MoaVbBicTaaOx; the first product is ethylene and the second product is acetic acid; the first linear velocity is about 136 cm / sec; at the first linear velocity a selectivity for ethylene is greater than about 85 %, and a selectivity for acetic acid is less than about 10 %; the second linear velocity is about 22 cm / sec; and at the second linear velocity a selectivity for ethylene is less than about 80 %, and a selectivity for acetic acid is greater than about 0 %.

[0026] In some embodiments, the catalyst includes a catalyst with the formula MoaVbBicTaaOx; the first product is acetic acid and the second product is ethylene; the first linear velocity is about 22 cm / sec; at the first linear velocity a selectivity for ethylene is less than about 80 %, and a selectivity for acetic acid is greater than about 0 %; the second linear velocity is about 136 cm / sec; and at the second linear velocity a selectivity for ethylene is greater than about 85 %, and a selectivity for acetic acid is less than about 10 %.

[0027] In some embodiments, the first feed stream and the second feed stream are the same. In some embodiments, the second feed stream includes the first feed stream and a diluent. In some embodiments, the first feed stream includes the second feed stream and a diluent.

[0028] In some embodiments, the catalyst includes a catalyst with the formula MoaVbTecTadOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral; or MoaVbBicTaaOx; wherein a is about 1.0; b is about 0.01 to about 0.5; c is about 0.005 to about 0.2; d is about 0.005 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral. In some embodiments, the catalyst includes a catalyst with the formula MoaVbTecTaaOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0029] In some embodiments, the catalyst includes a catalyst with the formula MoaVbBicTadOx; wherein a is about 1.0; b is about 0.01 to about 0.5; c is about 0.005 to about 0.2; d is about 0.005 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0030] BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 shows a schematic for a reactor.

[0032] Figure 2A shows a graph of X-ray diffraction (XRD) results.

[0033] Figure 2B shows a graph of XRD results.

[0034] Figures 3A-3B depict a flowchart of a mass balance method.

[0035] Figure 4A shows a graph of product selectivity and reactant conversion as a function of gas hourly space velocity (GHSV) for an exemplary MoaVbTecTaaOx catalyst.

[0036] Figure 4B shows a graph of product selectivity and reactant conversion as a function of linear velocity for an exemplary MoaVbTecTaaOx catalyst.

[0037] Figure 5A shows a graph of product selectivity and reactant conversion as a function of GHSV for an exemplary MoaVbBicTadOx catalyst.

[0038] Figure 5B shows a graph of product selectivity and reactant conversion as a function of linear velocity for an exemplary MoaVbBicTadOx catalyst.

[0039] Figure 6 shows a graph of XRD results.

[0040] Figure 7 shows a graph of XRD results.

[0041] Figure 8A shows a graph of product selectivity and reactant conversion as a function of GHSV for an exemplary MoaVbTecNbaOx catalyst.

[0042] Figure 8B shows a graph of product selectivity and reactant conversion as a function of linear velocity for an exemplary MoaVbTecNbaOx catalyst.

[0043] DESCRIPTION OF EMBODIMENTS

[0044] Reference will now be made in detail to certain embodiments of the disclosed subject matter. 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.

[0045] 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. The systems and methods of the present disclosure can allow for the maximization of an alpha-olefin product in the oxidation of the corresponding alkane while minimizing unwanted products. For example, the systems and methods can be used for the maximization of the production of ethylene in the oxidative dehydrogenation of ethane while minimizing production of acetic acid. Alternatively, the systems and methods can maximize the production of a byproduct while minimizing production of the alpha-olefin, such as maximizing the production of acetic acid while minimizing production of ethylene in the oxidative dehydrogenation of ethane. Thus, production of different products can be varied relatively easily based on market demand.

[0046] The systems and methods of the present disclosure can reduce the reactor size used as the reactor will be operated at a relatively high GHSV, thereby reducing associated capital expenditures. Without wishing to be bound by theory, it is believed that if the same conversion can be achieved at a higher GHSV, for the same volumetric flow of feed, a smaller catalyst bed volume could be used, which would result in the smaller reactor. Without wishing to be bound by theory, it is believed that increasing the linear velocity allows for improved heat removal from the reactor as increasing the linear velocity increases the pressure drop across the reactor. Additionally, this can result in fewer undesired side reactions.

[0047] The systems and methods of the present disclosure can reduce hot spots inside the catalyst bed due to increased reactor catalyst bed thermal conductivity and reactor interior wall heat transfer coefficient, resulting from increasing the linear velocity (or GHSV when reactor size / geometry is fixed). The systems and methods can reduce reaction thermal runaway.

[0048] Definitions

[0049] Unless otherwise defined, all technical and scientific terms used in this document have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. Methods and materials are described in this document for use in the present application; other, suitable methods and materials known in the art can also be used. The materials, methods, and examples are illustrative only and not intended to be limiting. All publications, patent applications, patents, sequences, database entries, and other references mentioned in this document are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control.

[0050] Values expressed in a range format should be interpreted in a flexible manner 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. For example, a range of “about 0.1% to about 5 %” or “about 0.1 % to 5 %” should be interpreted to include not just about 0.1% to about 5 %, but also the individual values (for example, 1 %, 2 %, 3 %, and 4 %) and the sub-ranges (for example, 0.1 % to 0.5 %, 1.1% to 2.2 %, and 3.3 % to 4.4 %) within the indicated range. The statement “about X to Y” has the same meaning as “about X to about Y”, unless indicated otherwise. Likewise, the statement “about X, Y, or about Z” has the same meaning as “about X, about Y, or about Z”, unless indicated otherwise.

[0051] The term “about,” as used in this disclosure, can allow for a degree of variability in a value or range, for example, within 10 %, within 5 %, or within 1 % of a stated value or of a stated limit of a range.

[0052] As used in this disclosure, the terms “a”, “an”, and “the” are used 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.” In addition, it is to be understood that the phraseology or terminology employed in this disclosure, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section.

[0053] In the methods described in this disclosure, 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.

[0054] As used herein, the term “catalyst” generally refers to the active catalyst portion of a catalyst material. The catalyst is generally 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.

[0055] Systems and Methods to Alter the Ethylene and / or Acetic Acid Yield in the Catalytic Oxidative Dehydrogenation of Ethane using the Reactor Space Velocity

[0056] Figure 1 depicts a schematic for a reactor 1000 used in the oxidative dehydrogenation of ethylene. A feed stream 1010 containing ethane, oxygen and an optional diluent is input into the reactor 1000. The reactor includes a catalyst 1020 that performs the oxidative dehydrogenation, generating ethylene, acetic acid, carbon dioxide and carbon monoxide from the feed stream 1010. A product stream 1030 containing the ethylene, acetic acid, carbon dioxide and carbon monoxide, exits the reactor 1000. The product stream 1030 can further include unreacted ethane and oxygen and the optional diluent.

[0057] Examples of the diluent in the feed stream 1010 include nitrogen gas, steam, CO2, argon, methane, or any either non-reactive gas, or reactive gas provided that the exotherm of the reaction of reactive gas is lower that the exotherm of the ethane ODH reaction.

[0058] Increasing the GHSV or linear velocity increases the ethylene selectivity and decreases the acetic acid selectivity of the process. Additionally, decreasing the GHSV or linear velocity in the reactor 1000 decreases the ethylene selectivity and increases the acetic acid selectivity. Thus, the GHSV or linear velocity can be selected and / or altered to maximize production of either ethylene or acetic acid. In addition or alternative to the oxidative dehydrogenation of ethane to ethylene, the systems and methods can be used for the oxidative dehydrogenation of other alkanes to form the corresponding alpha-olefins, such as the oxidative dehydrogenation of propane to propene. Additional alkanes (e.g., propane, butane, pentane) may be present in the feed stream 1010.

[0059] A method of the disclosure can include selecting a first product from the group consisting of ethylene and acetic acid, selecting a GHSV or linear velocity, contacting a feed stream including ethane and oxygen with a catalyst at the selected GHSV or linear velocity, and converting at least a portion of the ethane into the first product.

[0060] In some embodiments, the catalyst 1020 is a catalyst with the formula MoaVbTecTadOx, where a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral. In some embodiments, the catalyst 1020 is a catalyst with the formula MoaVbSbcTaaOx, where a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral. In some embodiments, the catalyst 1020 is a catalyst with the formula MoaVbTecNbdOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral. In some embodiments, the catalyst 1020 is a catalyst with the formula MoaVbBicTaaOx, where a is about 1.0; b is about 0.01 to about 0.5; c is about 0.005 to about 0.2; d is about 0.005 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0061] In some embodiments, a first product selected from ethylene and acetic acid is made at a first GHSV or linear velocity, then a second product selected from ethylene and acetic acid and different from the first product is made at a second GHSV or linear velocity different from the first GHSV or linear velocity.

[0062] A method of the disclosure can include contacting a first feed stream including ethane and oxygen with a catalyst at a first gas hourly space velocity (GHSV) or linear velocity, converting at least a portion of the ethane into a first product, contacting a second feed stream including ethane and oxygen with the catalyst at a second GHSV or linear velocity, and converting at least a portion of the ethane into a second product. The second GHSV or linear velocity is different from the first GHSV or linear velocity. The first product and second product are independently selected from the group consisting of ethylene and acetic acid and the second product is different from the first product. In some embodiments, the first feed stream and the second feed stream are the same. In some embodiments, the first feed stream corresponds to the second feed stream with a diluent, such as steam. In some embodiments, the second feed stream corresponds to the first feed stream with a diluent, such as steam. In some embodiments, the amount of the diluent is increased or decreased to alter the GHSV.

[0063] In some embodiments, the catalyst 1020 is a catalyst with the formula MoaVbTecTadOx, where a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral. In some embodiments, the catalyst 1020 is a catalyst with the formula MoaVbSbcTaaOx, where a is 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral. In some embodiments, the catalyst 1020 is a catalyst with the formula MoaVbTecNbdOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral. In some embodiments, the catalyst 1020 is a catalyst with the formula MoaVbBicTaaOx, where a is about 1.0; b is about 0.01 to about 0.5; c is about 0.005 to about 0.2; d is about 0.005 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0064] Catalysts

[0065] In some embodiments, the catalyst 1020 contains molybdenum (Mo); vanadium (V); tellurium (Te) or antimony (Sb), or both; tantalum (Ta) or niobium (Nb), or both; and oxygen (O).

[0066] In some embodiments, the catalyst 1020 has the formula MoaVbTecTadOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral. In some embodiments, the catalyst 1020 has the formula MoaVbSbcTaaOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0067] In some embodiments, the catalyst 1020 has the formula MoaVbTecNbaOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0068] In some embodiments, the catalyst 1020 has the formula MoaVbSbcTaaOx; wherein a is about 1.0; b is about 0.01 to about 0.4; c is about 0.01 to about 0.2; d is about 0.01 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0069] In some embodiments, the reagents used for synthesis have the following stoichiometry MoiVo.3iTao.o5(Bi, Sb or Te)o.o50x. In some embodiments, the catalyst has a stoichiometry by energy dispersive x-ray analysis of Mo1V0.32Ta0.02Te0.05Ox, Mo1V0.32Ta0.02Sb0.05Ox, or Mo1V0.33Ta0.04Bi0.05Ox.

[0070] In general, the values of a, b, c, and d may refer to the values based on the amount (molar equivalents) of each metal oxide added to the slurry, or may refer to values measured by elemental analysis, for example by inductively coupled plasma mass spectroscopy (ICP- MS), neutron activation analysis (NAA), x-ray fluorescence (XRF), ion chromatography mass spectrometry (IC-MS), proton induced x-ray emission (PIXE), or energy-dispersive x- ray spectroscopy (EDX).

[0071] In some embodiments, the catalyst 1020 is a catalyst described in U.S. Provisional Application No. 63 / 489,897 and / or PCT Application No. PCT / IB2024 / 052374, which are each herein incorporated by reference in its entirety.

[0072] In some embodiments, the catalysts contain molybdenum (Mo); vanadium (V); bismuth (Bi); tantalum (Ta) or niobium (Nb), or both; and oxygen (O).

[0073] In some embodiments, the catalyst 1020 has the formula MoaVbBicTaaOx; wherein a is about 1.0; b is about 0.01 to about 0.5; c is about 0.005 to about 0.2; d is about 0.005 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0074] In some embodiments, the catalyst 1020 has the formula MoaVbBicNbaOx; wherein a is about 1.0; b is about 0.01 to about 0.5; c is about 0.005 to about 0.2; d is about 0.005 to about 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral. In some embodiments, the catalyst 1020 is a catalyst described in U.S. Provisional Application No. 63 / 489,902 and / or PCT Application No. PCT / IB2024 / 052375, which are each herein incorporated by reference in its entirety.

[0075] Methods to prepare catalysts 1020 are described in U.S. Provisional Application No. 63 / 489,897 and U.S. Provisional Application No. 63 / 489,902.

[0076] GHSV and Uinear Velocity

[0077] In some embodiments, to form ethylene with the catalyst MoaVbTecTaaOx, the GHSV is at least about 500 (e.g., at least about 600, at least about 700, at least about 800, at least about 900, at least about 1000, at least about 2000, at least about 3000, at least about 4000, at least about 5000, at least about 6000, at least about 7000, at least about 8000, at least about 9000, at least about 10000, at least about 11000, at least about 12000, at least about 13000, at least about 14000, at least about 15000, at least about 16000, at least about 17000, at least about 18000, at least about 19000) h'1and / or at most about 20000 (e.g., at most about 19000, at most about 18000, at most about 17000, at most about 16000, at most about 15000, at most about 14000, at most about 13000, at most about 12000, at most about 11000, at most about 10000, at most about 9000, at most about 8000, at most about 7000, at most about 6000, at most about 5000, at most about 4000, at most about 3000, at most about 2000, at most about 1000, at most about 900, at most about 800, at about most 700, at most about 600) h’1. Without wishing to be bound by theory, it is believed that increasing GHSV leads to an increase in ethylene selectivity.

[0078] In some embodiments, to form acetic acid with the catalyst MoaVbTecTaaOx, the GHSV is at least about 500 (e.g., at least about 600, at least about 700, at least about 800, at least about 900, at least about 1000, at least about 2000, at least about 3000, at least about 4000, at least about 5000, at least about 6000, at least about 7000, at least about 8000, at least about 9000, at least about 10000, at least about 11000, at least about 12000, at least about 13000, at least about 14000, at least about 15000, at least about 16000, at least about 17000, at least about 18000, at least about 19000, at least about 20000, at least about 21000, at least about 22000, at least about 23000, at least about 24000, at least about 25000, at least about 26000, at least about 27000, at least about 28000, at least about 29000) h'1and / or at most about 30000 (e.g., at most about 29000, at most about 28000, at most about 27000, at most about 26000, at most about 25000, at most about 24000, at most about 23000, at most about 22000, at most about 21000, at most about 20000, at most about 19000, at most about 18000, at most about 17000, at most about 16000, at most about 15000, at most about 14000, at most about 13000, at most about 12000, at most about 11000, at most about 10000, at most about 9000, at most about 8000, at most about 7000, at most about 6000, at most about 5000, at most about 4000, at most about 3000, at most about 2000, at most about 1000, at most about 900, at most about 800, at most about 700, at most about 600) h'1.

[0079] In some embodiments, at a GHSV of about 4776 h’1, a catalyst with the formula MoaVbTecTaaOx has a selectivity for ethylene of at least about 70 (e.g., at least about 71, at least about 72, at least about 73, at least about 74, at least about 75, at least about 76, at least about 77, at least about 78, at least about 79, at least about 80, at least about 81, at least about 82, at least about 83, at least about 84, at least about 85, at least about 86, at least about 87, at least about 88, at least about 89, at least about 90, at least about 91, at least about 92, at least about 93, at least about 94, at least about 95, at least about 96, at least about 97, at least about 98) % and / or at most about 99 (e.g., at most about 98, at most about 97, at most about 96, at most about 95, at most about 94, at most about 93, at most about 92, at most about 91, at most about 90, at most about 89, at most about 88, at most about 87, at most about 86, at most about 85, at most about 84, at most about 83, at most about 82, at most about 81, at most about 80, at most about 79, at most about 78, at most about 77, at most about 76, at most about 75, at most about 74, at most about 73, at most about 72, at most about 71) %. In some embodiments, at a GHSV of about 4776 h’1, a catalyst with the formula MoaVbTecTadOx has a selectivity for ethylene of about 72.30 %.

[0080] In some embodiments, at a GHSV of about 4776 h’1, a catalyst with the formula MoaVbTecTadOx has a selectivity for acetic acid of at least about 15.73 (e.g., at least about 15.75, at least about 15.8, at least about 15.9, at least about 16, at least about 16.1, at least about 16.2, at least about 16.3, at least about 16.4, at least about 16.5, at least about 16.6, at least about 16.7, at least about 16.8, at least about 16.9, at least about 17, at least about 17. 1) % and / or at most about 17. 11 (e.g., at most about 17.1, at most about 17, at most about 16.9, at most about 16.8, at most about 16.7, at most about 16.6, at most about 16.5, at most about 16.4, at most about 16.3, at most about 16.2, at most about 16.1, at most about 15.9, at most about 15.8, at most about 15.75) %. In some embodiments, at a GHSV of about 4776 h’1, a catalyst with the formula MoaVbTecTadOx has a selectivity for acetic acid of about 16.52 %.

[0081] In some embodiments, at a GHSV of about 9440 h’1, a catalyst with the formula MoaVbTecTadOx has a selectivity for ethylene of at least about 73.91 (e.g., at least about 74, at least about 74.1, at least about 74.2,) % and / or at most about 74.29 (e.g., at most about 74.2, at most about 74.1, at most about 74) %. In some embodiments, at a GHSV of about 9440 h’1, a catalyst with the formula MoaVbTecTadOx has a selectivity for ethylene of about 74.9 %. In some embodiments, at a GHSV of about 14144 h’1, a catalyst with the formula MoaVbTecTaaOx has a selectivity for ethylene of at least about 75.74 (e.g., at least about 75.8, at least about 75.9, at least about 76, at least about 76.1, at least about 76.2, at least about

[0082] 76.3, at least about 76.4, at least about 76.5, at least about 76.6) % and / or at most about 76.67 (e.g., at most about 76.6, at most about 76.5, at most about 76.4, at most about 76.3, at most about 76.2, at most about 76.1, at most about 76, at most about 75.9, at most about 75.8) %. In some embodiments, at a GHSV of about 14144 h’1, a catalyst with the formula MoaVbTecTadOx has a selectivity for ethylene of about 76.3 %.

[0083] In some embodiments, at a GHSV of about 14144 h’1, a catalyst with the formula MoaVbTecTadOx has a selectivity for acetic acid of at least about 9.61 (e.g., at least about 9.7, at least about 9.8, at least about 9.9, at least about 10, at least about 10.1, at least about 10.2, at least about 10.3, at least about 10.4, at least about 10.5, at least about 10.6, at least about 10.7, at least about 10.8, at least about 10.9, at least about 11, at least about 11.1, at least about 11.2, at least about 11.3) % and / or at most about 11.33 (e.g., at most about 11.3, at most about 11.2, at most about 11.1, at most about 11, at most about 10.9, at most about 10.8, at most about 10.7, at most about 10.6, at most about 10.5, at most about 10.4, at most about

[0084] 10.3, at most about 10.2, at most about 10.1, at most about 10, at most about 9.9, at most about 9.8, at most about 9.7) %. In some embodiments, at a GHSV of about 14144 h’1, a catalyst with the formula MoaVbTecTadOx has a selectivity for acetic acid of about 10.32 %.

[0085] In some embodiments, to form ethylene with the catalyst MoaVbTecTadOx, the linear velocity is at least about 23 (e.g., at least about 24, at least about 25, at least about 26, at least about 27, at least about 28, at least about 29, at least about 30, at least about 31, at least about 32, at least about 33, at least about 34, at least about 35, at least about 36, at least about 37, at least about 38, at least about 39, at least about 40, at least about 41, at least about 42, at least about 43, at least about 44, at least about 45, at least about 46, at least about 47, at least about 48, at least about 49, at least about 50, at least about 51, at least about 52, at least about 53, at least about 54, at least about 55, at least about 56, at least about 57, at least about 58, at least about 59, at least about 60, at least about 61, at least about 62, at least about 63, at least about 64, at least about 65, at least about 66) cm / sec and / or at most about 67 (e.g., at most about 66, at most about 65, at most about 64, at most about 63, at most about 62, at most about 61, at most about 60, at most about 59, at most about 58, at most about 57, at most about at most about 56, at most about 55, at most about 54, at most about 53, at most about 52, at most about 51, at most about 50, at most about 49, at most about 48, at most about 47, at most about 46, at most about 45, at most about 44, at most about 43, at most about 42, at most about 41, at most about 40, at most about 39, at most about 38, at most about 37, at most about 36, at most about 35, at most about 34, at most about 33, at most about 32, at most about 31, at most about 30, at most about 29, at most about 28, at most about 27, at most about 26, at most about 25, at most about 24) cm / sec. Without wishing to be bound by theory, it is believed that increasing the linear velocity increases the ethylene selectivity.

[0086] In some embodiments, to form acetic acid with the catalyst MoaVbTccTajOx. the linear velocity is at least about 23 (e.g., at least about 24, at least about 25, at least about 26, at least about 27, at least about 28, at least about 29, at least about 30, at least about 31, at least about 32, at least about 33, at least about 34, at least about 35, at least about 36, at least about 37, at least about 38, at least about 39, at least about 40, at least about 41, at least about 42, at least about 43, at least about 44, at least about 45, at least about 46, at least about 47, at least about 48, at least about 49, at least about 50, at least about 51, at least about 52, at least about 53, at least about 54, at least about 55, at least about 56, at least about 57, at least about 58, at least about 59, at least about 60, at least about 61, at least about 62, at least about 63, at least about 64, at least about 65, at least about 66) cm / sec and / or at most about 67 (e.g., at most about 66, at most about 65, at most about 64, at most about 63, at most about 62, at most about 61, at most about 60, at most about 59, at most about 58, at most about 57, at most about at most about 56, at most about 55, at most about 54, at most about 53, at most about 52, at most about 51, at most about 50, at most about 49, at most about 48, at most about 47, at most about 46, at most about 45, at most about 44, at most about 43, at most about 42, at most about 41, at most about 40, at most about 39, at most about 38, at most about 37, at most about 36, at most about 35, at most about 34, at most about 33, at most about 32, at most about 31, at most about 30, at most about 29, at most about 28, at most about 27, at most about 26, at most about 25, at most about 24) cm / sec. Without wishing to be bound by theory, it is believed that decreasing the linear velocity decreases the ethylene selectivity.

[0087] In some embodiments, at a linear velocity of about 23 cm / sec, a catalyst with the formula MoaVbTecTaaOx has a selectivity for ethylene of at least about 72.02 (e.g., at least about 72.1, at least about 72.2, at least about 72.3, at least about 72.4, at least about 72.5, at least about 72.6, at least about 72.7) % and / or at most about 72.71 (e.g., at most about 72.7, at most about 72.6, at most about 72.5, at most about 72.4, at most about 72.3, at most about 72.2, at most about 72. 1) %. In some embodiments, at a linear velocity of about 23 cm / sec, a catalyst with the formula MoaVbTecTaaOx has a selectivity for ethylene of about 72.30 %.

[0088] In some embodiments, at a linear velocity of about 23 cm / sec, a catalyst with the formula MoaVbTecTaaOx has a selectivity for acetic acid of at least about 15.73 (e.g., at least about 15.8, at least about 15.9, at least about 16, at least about 16.1, at least about 16.2, at least about 16.3, at least about 16.4, at least about 16.5, at least about 16.6, at least about 16.7, at least about 16.8, at least about 16.9, at least about 17, at least about 17.1) % and / or at most about 17.11 (e.g., at most about 17.1, at most about 17, at most about 16.9, at most about 16.8, at most about 16.7, at most about 16.6, at most about 16.5, at most about 16.4, at most about 16.3, at most about 16.2, at most about 16.1, at most about 16, at most about 15.9, at most about 15.8) %. In some embodiments, at a linear velocity of about 23 cm / sec, a catalyst with the formula MoaVbTecTaaOx can has selectivity for acetic acid of about 16.52 %.

[0089] In some embodiments, at a linear velocity of about 45 cm / sec, a catalyst with the formula MoaVbTecTaaOx has a selectivity for ethylene of at least about 73.91 (e.g., at least about 74, at least about 74.1, at least about 74.2) % and / or at most 74.29 (e.g., at most about

[0090] 74.2, at most about 74. 1, at most about 74) %. In some embodiments, at a linear velocity of about 45 cm / sec, a catalyst with the formula MoaVbTecTaaOx has a selectivity for ethylene of about 74.09 %.

[0091] In some embodiments, at a linear velocity of about 45 cm / sec, a catalyst with the formula MoaVbTecTaaOx has a selectivity for acetic acid of at least 13.47 (e.g., at least about 13.5, at least about 13.6, at least about 13.7, at least about 13.8, at least about 13.9, at least about 14, at least about 14.1) % and / or at most 14. 12 (e.g., at most about 14.1, at most about 14, most about 13.9, at most about 13.8, at most about 13.7, at most about 13.6, at most about 13.5) %. In some embodiments, at a linear velocity of about 45 cm / sec, a catalyst with the formula MoaVbTecTaaOx can has selectivity for acetic acid of about 13.84.

[0092] In some embodiments, at a linear velocity of about 67 cm / sec, a catalyst with the formula MoaVbTecTaaOx has a selectivity for ethylene of at least about 75.74 (e.g., at least about 75.8, at least about 75.9, at least about 76, at least about 76.1, at least about 76.2, at least about 76.3, at least about 76.4, at least about 76.5, at least about 76.6) % and / or at most about 76.67 (e.g., at most about 76.6, at most about 76.5, at most about 76.4, at most about

[0093] 76.3, at most about 76.2, at most about 76.1, at most about 76, at most about 75.9, at most about 75.8) %. In some embodiments, at a linear velocity of about 67 cm / sec, a catalyst with the formula MoaVbTecTaaOx has a selectivity for ethylene of about 76.30 %.

[0094] In some embodiments, at a linear velocity of about 67 cm / sec, a catalyst with the formula MoaVbTecTaaOx has a selectivity for acetic acid of at least about 9.61 (e.g., at least about 9.7, at least about 9.8, at least about 9.9, at least about 10, at least about 10.1, at least about 10.2, at least about 10.3, at least about 10.4, at least about 10.5, at least about 10.6, at least about 10.7, at least about 10.8, at least about 10.9, at least about 11, at least about 11.1, at least about 11.2, at least about 11.3) % and / or at most about 11.33 (e.g., at most about 11.3, at most about 11.2, at most about 11.1, at most about 11, at most about 10.9, at most about 10.8, at most about 10.7, at most about 10.6, at most about 10.5, at most about 10.4, at most about 10.3, at most about 10.2, at most about 10.1, at most about 10, at most about 9.9, at most about 9.8, at most about 9.7) %. In some embodiments, at a linear velocity of about 67 cm / sec, a catalyst with the formula MoaVbTccTajOx can has selectivity for acetic acid of about 10.32 %.

[0095] In some embodiments, to form ethylene with the catalyst MoaVbBicTaaOx, the GHSV is at least about 4714 (e.g., at least about 5000, at least about 6000, at least about 7000, at least about 8000, at least about 9000, at least about 10000, at least about 11000, at least about 12000, at least about 13000, at least about 14000, at least about 15000, at least about 16000, at least about 17000, at least about 18000, at least about 19000, at least about 20000, at least about 21000, at least about 22000, at least about 23000, at least about 24000, at least about 25000, at least about 26000, at least about 27000, at least about 28000) h'1and / or at most about 28266 (e.g., at most about 28000, at most about 27000, at most about 26000, at most about 25000, at most about 24000, at most about 23000, at most about 22000, at most about 21000, at most about 20000, at most about 19000, at most about 18000, at most about 17000, at most about 16000, at most about 15000, at most about 14000, at most about 13000, at most about 12000, at most about 11000, at most about 10000, at most about 9000, at most about 8000, at most about 7000, at most about 6000, at most about 5000) h’1.

[0096] In some embodiments, to form acetic acid with the catalyst MoaVbBicTaaOx, the GHSV is at least about 4714 (e.g., at least about 5000, at least about 6000, at least about 7000, at least about 8000, at least about 9000, at least about 10000, at least about 11000, at least about 12000, at least about 13000, at least about 14000, at least about 15000, at least about 16000, at least about 17000, at least about 18000, at least about 19000, at least about 20000, at least about 21000, at least about 22000, at least about 23000, at least about 24000, at least about 25000, at least about 26000, at least about 27000, at least about 28000) h'1and / or at most about 28266 (e.g., at most about 28000, at most about 27000, at most about 26000, at most about 25000, at most about 24000, at most about 23000, at most about 22000, at most about 21000, at most about 20000, at most about 19000, at most about 18000, at most about 17000, at most about 16000, at most about 15000, at most about 14000, at most about 13000, at most about 12000, at most about 11000, at most about 10000, at most about 9000, at most about 8000, at most about 7000, at most about 6000, at most about 5000) h’1. In some embodiments, at a GHSV of about 4714 h’1, a catalyst with the formula MoaVbBicTaaOx has a selectivity for ethylene of at least about 70 (e.g., at least about 71, at least about 72, at least about 73, at least about 74, at least about 75, at least about 76, at least about 77, at least about 78, at least about 79, at least about 80, at least about 81, at least about 82, at least about 83, at least about 84, at least about 85, at least about 86, at least about 87, at least about 88, at least about 89, at least about 90, at least about 91, at least about 92, at least about 93, at least about 94, at least about 95, at least about 96, at least about 97, at least about 98) % and / or at most about 99 (e.g., at most about 98, at most about 97, at most about 96, at most about 95, at most about 94, at most about 93, at most about 92, at most about 91, at most about 90, at most about 89, at most about 88, at most about 87, at most about 86, at most about 85, at most about 84, at most about 83, at most about 82, at most about 81, at most about 80, at most about 79, at most about 78, at most about 77, at most about 76, at most about 75, at most about 74, at most about 73, at most about 72, at most about 71) %. In some embodiments, at a GHSV of about 4714 h’1, a catalyst with the formula MoaVbBicTaaOx has a selectivity for ethylene of about 86.52 %. Without wishing to be bound by theory, it is believed that increasing the GHSV increases the selectivity towards ethylene.

[0097] In some embodiments, at a GHSV of about 4714 h’1, a catalyst with the formula MoaVbBicTadOx has a selectivity for acetic acid of at least 4.38 (e.g., at least about 4.4, at least about 4.5, at least about 4.6, at least about 4.7, at least about 4.8, at least about 4.9, at least about 5, at least about 5.1, at least about 5.2, at least about 5.3, at least about 5.4, at least about 5.5, at least about 5.6, at least about 5.7, at least about 5.8, at least about 5.9, at least about 6, at least about 6.1, at least about 6.2, at least about 6.3, at least about 6.4, at least about 6.5, at least about 6.6, at least about 6.7, at least about 6.8, at least about 6.9, at least about 7.0, at least about 7.1, at least about 7.2, at least about 7.3, at least about 7.4, at least about 7.5, at least about 7.6, at least about 7.7, at least about 7.8, at least about 7.9, at least about 8, at least about 8.1, at least about 8.2, at least about 8.3, at least about 8.4, at least about 8.5, at least about 8.6, at least about 8.7, at least about 8.8, at least about 8.9, at least about 9, at least about 9.1, at least about 9.2, at least about 9.3) % and / or at most 9.40 (e.g., at most about 9.3, at most about 9.2, at most about 9.1, at most about 9, at most about 8.9, at most about 8.8, at most about 8.7, at most about 8.6, at most about 8.5, at most about 8.4, at most about 8.3, at most about 8.2, at most about 8.1, at most about 8, at most about 7.9, at most about 7.8, at most about 7.7, at most about 7.6, at most about 7.5, at most about 7.4, at most about 7.3, at most about 7.2, at most about 7.1, at most about 7, at most about 6.9, at most about 6.8, at most about 6.7, at most about 6.6, at most about 6.5, at most about 6.4, at most about 6.3, at most about 6.2, at most about 6.1, at most about 6, at most about 5.9, at most about 5.8, at most about 5.7, at most about 5.6, at most about 5.5, at most about 5.4, at most about 5.3, at most about 5.2, at least about 5.1, at most about 5, at most about 4.9, at most about 4.8, at most about 4.7, at most about 4.6, at most about 4.5, at most about 4.4) %. In some embodiments, at a GHSV of about 4714 h’1, a catalyst with the formula MoaVbBicTadOx has a selectivity for acetic acid of about 6.31 %.

[0098] In some embodiments, at a GHSV of about 14133 h’1, a catalyst with the formula MoaVbBicTadOx has a selectivity for ethylene of at least about 87.77 (e.g., at least about 87.8, at least about 87.9, at least about 88, at least about 88.1, at least about 88.2, at least about 88.3, at least about 88.4, at least about 88.5, at least about 88.6, at least about 88.7, at least about 88.8, at least about 88.9, at least about 89, at least about 89.1, at least about 89.2, at least about 89.3, at least about 89.4, at least about 89.5, at least about 89.6, at least about 89.7, at least about 89.8) % and / or at most about 89.86 (e.g., at most about 89.8, at most about 89.7, at most about 89.6, at most about 89.5, at most about 89.4, at most about 89.3, at most about 89.2, at most about 89.1, at most about 89, at most about 88.9, at most about 88.8, at most about 88.7, at most about 88.6, at most about 88.5, at most about 88.4, at most about 88.3, at most about 88.2, at most about 88. 1, at most about 88, at most about 87.9, at most about 87.8) %. In some embodiments, at a GHSV of about 14133 h’1, a catalyst with the formula MoaVbBicTadOx has a selectivity for ethylene of about 88.51 %.

[0099] In some embodiments, at a GHSV of about 14133 h’1, a catalyst with the formula MoaVbBicTadOx has a selectivity for acetic acid of at least about 2.29 (e.g., at least about 2.3, at least about 2.4, at least about 2.5, at least about 2.6, at least about 2.7, at least about 2.8, at least about 2.9, at least about 3, at least about 3. 1, at least about 3.2, at least about 3.3, at least about 3.4, at least about 3.5, at least about 3.6, at least about 3.7, at least about 3.8, at least about 3.9, at least about 4, at least about 4.1, at least about 4.2, at least about 4.3, at least about 4.4, at least about 4.5, at least about 4.6, at least about 4.7, at least about 4.8) % and / or at most about 4.88 (e.g., at most about 4.8, at most about 4.7, at most about 4.6, at most about 4.5, at most about 4.4, at most about 4.3, at most about 4.2, at most about 4.1, at most about 4, at most about 3.9, at most about 3.8, at most about 3.7, at most about 3.6, at most about 3.5, at most about 3.4, at most about 3.3, at most about 3.2, at most about 3.1, at most about 3, at most about 2.9, at most about 2.8, at most about 2.7, at most about 2.6, at most about 2.5, at most about 2.4, at most about 2.3) %. In some embodiments, at a GHSV of about 14133 h’1, a catalyst with the formula MoaVbBicTadOx has a selectivity for acetic acid of about 3.98 %. In some embodiments, at a GHSV of about 23568 h’1, a catalyst with the formula MoaVbBicTaaOx has a selectivity for ethylene of at least about 90.64 (e.g., at least about 90.7, at least about 90.8, at least about 90.9, at least about 91, at least about 91.1, at least about

[0100] 91.2, at least about 91.3, at least about 91.4, at least about 91.5, at least about 91.6, at least about 91.7, at least about 91.8, at least about 91.9) % and / or at most about 91.91 (e.g., at most about 91.9, at most about 91.8, at most about 91.7, at most about 91.6, at most about 91.5 at most about 91.4, at most about 91.3, at most about 91.2, at most about 91.1, at most about 91, at most about 90.9, at most about 90.8, at most about 90.7) %. In some embodiments, at a GHSV of about 23568 h’1, a catalyst with the formula MoaVbBicTadOx has a selectivity for ethylene of about 91.45 %.

[0101] In some embodiments, at a GHSV of about 23568 h’1, a catalyst with the formula MoaVbBicTadOx has a selectivity for acetic acid of at least about 0 (e.g., at least about 0.05, at least about 0.1, at least about 0.15, at least about 0.2, at least about 0.25, at least about 0.3, at least about 0.35, at least about 0.4, at least about 0.45, at least about 0.5, at least about 0.55, at least about 0.6, at least about 0.65, at least about 0.7, at least about 0.75, at least about 0.8, at least about 0.85, at least about 0.9, at least about 0.95) % and / or at most about 0.99 (e.g., at most about 0.95, at most about 0.9, at most about 0.85, at most about 0.8, at most about 0.75, at most about 0.7, at most about 0.65, at most about 0.6, at most about 0.55, at most about 0.5, at most about 0.45, at most about 0.4, at most about 0.35, at most about 0.3, at most about 0.25, at most about 0.2, at most about 0.15, at most about 0.1, at most about 0.05) %. In some embodiments, at a GHSV of about 23568 h’1, a catalyst with the formula MoaVbBicTadOx has a selectivity for acetic acid of about 0.18 %.

[0102] In some embodiments, at a GHSV of about 28266 h’1, a catalyst with the formula MoaVbBicTadOx has a selectivity for ethylene of at least about 91.56 (e.g., at least about 91.6, at least about 91.7, at least about 91.8, at least about 91.9, at least about 92, at least about 92. 1, at least about 92.2, at least about 92.3) % and / or at most about 92.33 (e.g., at most about

[0103] 92.3, at most about 92.2, at most about 92.1, at most about 92, at most about 91.9, at most about 91.8, at most about 9.17, at most about 91.6) %. In some embodiments, at a GHSV of about 28266 h’1, a catalyst with the formula MoaVbBicTadOx has a selectivity for ethylene of about 91.84 %.

[0104] In some embodiments, at a GHSV of about 28266 h’1, a catalyst with the formula MoaVbBicTadOx has a selectivity for acetic acid of at least about 0 (e.g., at least about 0.05, at least about 0.1, at least about 0.15, at least about 0.2) % and / or at most about 0.23 (e.g., at most about 0.2, at most about 0.15, at most about 0.1, at most about 0.05) %. In some embodiments, at a GHSV of about 28266 h’1, a catalyst with the formula MoaVbBicTaaOx has a selectivity for acetic acid of about 0.02 %.

[0105] In some embodiments, to form ethylene with the catalyst MoaVbBicTaaOx, the linear velocity is at least about 22 (e.g., at least about 25, at least about 30, at least about 35, at least about 40, at least about 45, at least about 50, at least about 55, at least about 60, at least about 65, at least about 70, at least about 75, at least about 80, at least about 85, at least about 90, at least about 95, at least about 100, at least about 105, at least about 110, at least about 115, at least about 120, at least about 125, at least about 130, at least about 135) cm / sec and / or at most about 136 (e.g., at most about 135, at most about 130, at most about 125, at most about 120, at most about 115, at most about 110, at most about 105, at most about 100, at most about 95, at most about 90, at most about 85, at most about 80, at most about 75, at most about 70, at most about 65, at most about 60, at most about 55, at most about 50, at most about 45, at most about 40, at most about 35, at most about 30, at most about 25) cm / sec.

[0106] Without wishing to be bound by theory, it is believed that increasing the linear velocity increases the ethylene selectivity.

[0107] In some embodiments, to form acetic acid with the catalyst MoaVbBicTaaOx, the linear velocity is at least about 22 (e.g., at least about 25, at least about 30, at least about 35, at least about 40, at least about 45, at least about 50, at least about 55, at least about 60, at least about 65, at least about 70, at least about 75, at least about 80, at least about 85, at least about 90, at least about 95, at least about 100, at least about 105, at least about 110, at least about 115, at least about 120, at least about 125, at least about 130, at least about 135) cm / sec and / or at most about 136 (e.g., at most about 135, at most about 130, at most about 125, at most about 120, at most about 115, at most about 110, at most about 105, at most about 100, at most about 95, at most about 90, at most about 85, at most about 80, at most about 75, at most about 70, at most about 65, at most about 60, at most about 55, at most about 50, at most about 45, at most about 40, at most about 35, at most about 30, at most about 25) cm / sec.

[0108] Without wishing to be bound by theory, it is believed that decreasing the linear velocity increases the acetic acid selectivity.

[0109] In some embodiments, at a linear velocity of about 22 cm / sec, a catalyst with the formula MoaVbBicTaaOx has a selectivity for ethylene of at least about 84.02 (e.g., at least about 84.1, at least about 84.2, at least about 84.3, at least about 84.4, at least about 84.5, at least about 84.6, at least about 84.7, at least about 84.8, at least about 84.9, at least about 85, at least about 85.1, at least about 85.2, at least about 85.3, at least about 85.4, at least about 85.5, at least about 85.6, at least about 85.7, at least about 85.8, at least about 85.9, at least about 86, at least about 86.1, at least about 86.2, at least about 86.3, at least about 86.4, at least about 86.5, at least about 86.6, at least about 86.7, at least about 86.8, at least about 86.9, at least about 87, at least about 87.1, at least about 87.2, at least about 87.3, at least about

[0110] 87.4, at least about 87.5, at least about 87.6, at least about 87.7, at least about 87.8, at least about 87.9, at least about 88, at least about 88.1) % and / or at most about 88.14 (e.g., at most about 88.1, at most about 88, at most about 87.9, at most about 87.8, at most about 87.7, at most about 87.6, at most about 87.5, at most about 87.4, at most about 87.3, at most about

[0111] 87.2, at most about 87.1, at most about 87, at most about 86.9, at most about 86.8, at most about 86.7, at most about 86.6, at most about 86.5, at most about 86.4, at most about 86.3, at most about 86.2, at most about 86.1, at most about 86, at most about 85.9, at most about 85.8, at most about 85.7, at most about 85.6, at most about 85.5, at most about 85.4, at most about

[0112] 85.3, at most about 85.2, at most about 85.1, at most about 85, at most about 84.9, at most about 84.8, at most about 84.7, at most about 84.6, at most about 84.5, at most about 84.4, at most about 84.3, at most about 84.2, at most about 84.1) %. In some embodiments, at a linear velocity of about 22 cm / sec, a catalyst with the formula MoaVbBicTaaOx has a selectivity for ethylene of about 86.52 %.

[0113] In some embodiments, at a linear velocity of about 22 cm / sec, a catalyst with the formula MoaVbBicTaaOx has a selectivity for acetic acid of at least about 4.38 (e.g., at least about 4.4, at least about 4.5, at least about 4.6, at least about 4.7, at least about 4.8, at least about 4.9, at least about 5, at least about 5.1, at least about 5.2, at least about 5.3, at least about

[0114] 5.4, at least about 5.5, at least about 5.6, at least about 5.7, at least about 5.8, at least about 5.9, at least about 6, at least about 6.1, at least about 6.2, at least about 6.3, at least about 6.4, at least about 6.5, at least about 6.6, at least about 6.7, at least about 6.8, at least about 6.9, at least about 7, at least about 7.1, at least about 7.2, at least about 7.3, at least about 7.4, at least about 7.5, at least about 7.6, at least about 7.7, at least about 7.8, at least about 7.9, at least about 8, at least about 8. 1, at least about 8.2, at least about 8.3, at least about 8.4, at least about

[0115] 8.5, at least about 8.6, at least about 8.7, at least about 8.8, at least about 8.9, at least about 9, at least about 9.1, at least about 9.2, at least about 9.3) % and / or at most about 9.40 (e.g., at most about 9.3, at most about 9.2, at most about 9.1, at most about 9, at most about 8.9, at most about 8.8, at most about 8.7, at most about 8.6, at most about 8.5, at most about 8.4, at most about 8.3, at most about 8.2, at most about 8.1, at most about 8, at most about 7.9, at most about 7.8, at most about 7.7, at most about 7.6, at most about 7.5, at most about 7.4, at most about 7.3, at most about 7.2, at most about 7.1, at most about 7, at most about 6.9, at most about 6.8, at most about 6.7, at most about 6.6, at most about 6.5, at most about 6.4, at most about 6.3, at most about 6.2, at most about 6.1, at most about 6, at most about 5.9, at most about 5.8, at most about 5.7, at most about 5.6, at most about 5.5, at most about 5.4, at most about 5.3, at most about 5.2, at most about 5.1, at most about 5, at most about 4.9, at most about 4.8, at most about 4.7, at most about 4.6, at most about 4.5, at most about 4.4) %. In some embodiments, at a linear velocity of about 22 cm / sec, a catalyst with the formula MoaVbBicTaaOx has a selectivity for acetic acid of about 6.31 %.

[0116] In some embodiments, at a linear velocity of about 66 cm / sec, a catalyst with the formula MoaVbBicTaaOx has a selectivity for ethylene of at least about 87.77 (e.g., at least about 87.8, at least about 87.9, at least about 88, at least about 88.1, at least about 88.2, at least about 88.3, at least about 88.4, at least about 88.5, at least about 88.6, at least about 88.7, at least about 88.8, at least about 88.9, at least about 89, at least about 89.1, at least about

[0117] 89.2, at least about 89.3, at least about 89.4, at least about 89.5, at least about 89.6, at least about 89.7, at least about 89.8) % and / or at most about 89.86 (e.g., at most about 89.8, at most about 89.7, at most about 89.6, at most about 89.5, at most about 89.4, at most about 89.3, at most about 89.2, at most about 89.1, at most about 89, at most about 88.9, at most about 88.8, at most about 88.7, at most about 88.6, at most about 88.5, at most about 88.4, at most about

[0118] 88.3, at least about 88.2, at most about 88.1, at most about 88, at most about 87.9, at most about 87.8) %. In some embodiments, at a linear velocity of about 66 cm / sec, a catalyst with the formula MoaVbBicTaaOx has a selectivity for ethylene of about 88.5 %.

[0119] In some embodiments, at a linear velocity of about 66 cm / sec, a catalyst with the formula MoaVbBicTaaOx has a selectivity for acetic acid of at least about 2.29 (e.g., at least about 2.3, at least about 2.4, at least about 2.5, at least about 2.6, at least about 2.7, at least about 2.8, at least about 2.9, at least about 3, at least about 3. 1, at least about 3.2, at least about

[0120] 3.3, at least about 3.4, at least about 3.5, at least about 3.6, at least about 3.7, at least about 3.8, at least about 3.9, at least about 4, at least about 4.1, at least about 4.2, at least about 4.3, at least about 4.4, at least about 4.5, at least about 4.6, at least about 4.7, at least about 4.8) % and / or at most about 4.88 (e.g., at most about 4.8, at most about 4.7, at most about 4.6, at most about 4.5, at most about 4.4, at most about 4.3, at most about 4.2, at most about 4.1, at most about 4, at most about 3.9, at most about 3.8, at most about 3.7, at most about 3.6, at most about 3.5, at most about 3.5, at most about 3.4, at most about 3.3, at most about 3.2, at most about 3.1, at most about 3, at most about 2.9, at most about 2.8, at most about 2.7, at most about 2.6, at most about 2.5, at most about 2.4, at most about 2.3) %. In some embodiments, at a linear velocity of about 66 cm / sec, a catalyst with the formula MoaVbBicTadOx has a selectivity for acetic acid of about 3.98 %. In some embodiments, at a linear velocity of about 112 cm / sec, a catalyst with the formula MoaVbBicTaaOx has a selectivity for ethylene of at least about 90.64 (e.g., at least about 90.7, at least about 90.8, at least about 90.9, at least about 91, at least about 91.1, at least about 91.2, at least about 91.3, at least about 91.4, at least about 91.5, at least about 91.6, at least about 91.7, at least about 91.8, at least about 91.9) % and / or at most 91.91 (e.g., at most about 91.9, at most about 91.8, at most about 91.7, at most about 91.6, at most about 91.5, at most about 91.4, at most about 91.3, at most about 91.2, at most about 91.1, at most about 91, at most about 90.9, at most about 90.8, at most about 90.7) %. In some embodiments, at a linear velocity of about 112 cm / sec, a catalyst with the formula MoaVbBicTadOx has a selectivity for ethylene of about 91.43 %.

[0121] In some embodiments, at a linear velocity of about 112 cm / sec, a catalyst with the formula MoaVbBicTadOx has a selectivity for acetic acid of at least about 0 (e.g., at least about 0.05, at least about 0. 1, at least about 0. 15, at least about 0.2, at least about 0.25, at least about 0.3, at least about 0.35, at least about 0.4, at least about 0.45, at least about 0.5, at least about 0.55, at least about 0.6, at least about 0.65, at least about 0.7, at least about 0.75, at least about 0.8, at least about 0.85, at least about 0.9, at least about 0.95) % and / or at most about 0.99 (e.g., at most about 0.95, at most about 0.9, at most about 0.85, at most about 0.8, at most about 0.75, at most about 0.7, at most about 0.65, at most about 0.6, at most about 0.55, at most about 0.5, at most about 0.45, at most about 0.4, at most about 0.35, at most about 0.3, at most about 0.25, at most about 0.2, at most about 0.15, at most about 0.1, at most about 0.05) %. In some embodiments, at a linear velocity of about 112 cm / sec, a catalyst with the formula MoaVbBicTadOx has a selectivity for acetic acid of about 0.18 %.

[0122] In some embodiments, at a linear velocity of about 136 cm / sec, a catalyst with the formula MoaVbBicTadOx has a selectivity for ethylene of at least about 91.56 (e.g., at least about 91.6, at least about 91.7, at least about 91.8, at least about 91.9, at least about 92, at least about 92.1, at least about 92.2, at least about 92.3) % and / or at most about 92.33 (e.g., 92.3, at most about 92.2, at most about 92.1, at most about 92, at most about 91.9, at most about 91.8, at most about 91.7, at most about 91.6) %. In some embodiments, at a linear velocity of about 136 cm / sec, a catalyst with the formula MoaVbBicTadOx has a selectivity for ethylene of about 91.84 %.

[0123] In some embodiments, at a linear velocity of about 136 cm / sec, a catalyst with the formula MoaVbBicTadOx has a selectivity for acetic acid of at least about 0 (e.g., at least about 0.05, at least about 0.1, at least about 0.15, at least about 0.2) % and / or at most about 0.23 (e.g., at most about 0.2, at most about 0.15, at most about 0. 1, at most about 0.05) %. In some embodiments, at a linear velocity of about 136 cm / sec, a catalyst with the formula MoaVbBicTaaOx has a selectivity for acetic acid of about 0.02 %.

[0124] Without wishing to be bound by theory, it is believed that the selectivities for ethylene and acetic acid as a function of GHSV and linear velocity, and the GSHV and linear velocities used to form ethylene and acetic acid for a catalyst with the formula MoaVbSbcTaaOx are similar to those for a catalyst with the formula MoaVbBicTaaOx.

[0125] As used herein, the GHSV in h'1can be calculated using the equation:

[0126] GHSV =

[0127] Volumetric flow rate of feed, gas and / or vapor entering the reactor (or feed flow rate) at STP . .

[0128] Volume of catalyst bed active phase '7where STP conditions are 1 atm and 21.11 °C. The volumetric flow rate of feed gas can be measured by mass flow controller from Brooks which uses thermal conductivity of the gas to regulate and control the flow rate. For vapor gas component (such as steam), a water mass syringe pump is used to regulate and control the flow rate. The vapor entering the reactor is calculated as:

[0129] _ Fwt*22.4 *1000 vo118.02 where Fvoiis the theoretical volumetric flow of vapor to the reactor at STP [seem], Fwt is the weight flow of water to the inlet of the steam generator / reactor inlet, as controlled and measured by the syringe pump [g / min], 18.02 is the molecular weight of water [g / mol], and 22.4 is the molar volume of ideal gas at STP [L / mol].

[0130] To determine the volume of catalyst bed active phase, a catalyst bed is loaded manually by the operator into the reactor tube and a measuring probe is used to specify the height of the loaded catalyst. Knowing the internal diameter of the reactor tube and height of the reactor tube, the volume of catalyst bed can be calculated.

[0131] As used herein, the linear velocity in cm / sec can be calculated using the equation: Linear Velocity =

[0132] Volumetric Flow rate of feed gas and / or vapor entering the reactor at reactor temperature and reactor inlet pressure / «\ cross section area of reactor tube x void fraction of catalyst bed ' '

[0133] The void fraction of catalyst bed is the fraction of volume of the void in the catalyst bed active phase measured experimentally.

[0134] As used herein, a selectivity to ethylene (SEthyiene) can be determined using equation: where SEthyiene is the selectivity to ethylene and X is the molar concentration of the corresponding compound in the gaseous effluent exiting the reactor at the corresponding temperature (the temperature at which reactor temperature is controlled and set to), as measured using about 2 g of catalyst, a target gas flow rate of 150 seem (WHSV = 3.57 h'1), a target pressure of 20 psig, a target feed gas composition of about 20 mol. % ethane, about 10 mol. % oxygen, and about 70 mol. % nitrogen, and a temperature of about 380°C to about 450°C.

[0135] As used herein, a selectivity to acetic acid (SAcetic Acid) was determined using the following equation: where SAcetic Acid is the selectivity to ethylene and X is the molar concentration of the corresponding compound in the gaseous effluent exiting the reactor at the corresponding temperature, as measured using about 2 g of catalyst, a target gas flow rate of 150 seem (WHSV = 3.57 h'1) a target pressure of 20 psig, a target feed gas composition of about 20 mol. % ethane, about 10 mol. % oxygen, and about 70 mol. % nitrogen, and a temperature of about 380°C to about 450°C.

[0136] EXAMPLES

[0137] Example 1 - Synthesis and Characterization of Catalysts

[0138] Molybdenum(VI) oxide (MoOs), vanadium(V) oxide (V2O5), tellurium dioxide (TeCh) and oxalic acid dihydrate were purchased from Sigma- Aldrich (product #’s 267856, 223794, 204552 and 247537, respectively). Amorphous bismuth(III) hydroxide (Bi(OH)3) was purchased from Alfa Aesar (product # 40397). Tantalum pentoxide hydrate (Ta2C>5 xH- 2O) was purchased from BassTech International (product # 11111). All reagents were used as is without any further purification.

[0139] MoaVbTecTadOx and MoaVbBicTaaOx were prepared with the solid reagents listed in Table 1. The solid reagents were mixed and lightly ground using a mortar and pestle, mainly to pulverize the larger oxalic acid dihydrate crystals to better disperse with the other solids. The solid mixture was then transferred into an 8 mb glass vial, after which 2 mb of distilled water was added. The sample was stirred lightly with a glass stir rod to form a thick orange slurry and another 1 mb of water was then used to rinse sample stuck to the stir rod back into the vial. The vial was then placed in a glass lined steel autoclave and water was filled around the vial to the level of the solids to help with heat transfer and to maintain a humid atmosphere in the vessel. The autoclave was then sealed and placed in an oven to heat from room temperature to 180°C over 12 hours, held at 180°C for 48 hours, then turned off to cool back to ambient temperature over 3 - 4 hours. After the reaction, the sample was a deep purple hard solid that had increased in volume by approximately 1.5x. The sample was scraped from the vial onto filter paper in a vacuum filtration set-up and was washed with approximately 50 mb of distilled water, with the filtrate being a clear, deep blue color. The sample was washed until the filtrate from the sample was colorless, then was left to dry on the filter paper to obtain shiny purple-black powdered solid. The solids were then calcined in a tubular autoclave under N2 flow for 12 hours at 60°C, after which they were heated to 600°C over 6 hours, held at 600°C for 2 hours, then the furnace was turned off and the sample was cooled back to ambient conditions over approximately 12 hours. The colors observed applied to both MoaVbTecTaaOx and MoaVbBicTadOx.

[0140] A catalyst containing Mo, V, Ta and Sb (MoaVbSbcTaaOx) was also prepared using the procedures described above.

[0141] Table 1. Amounts of Reagents Used to Prepare Catalyst Samples

[0142] The reagents used for the synthesis had the stoichiometry MoiVo.3iTao.o5(Bi, Sb or Te)o.o50x. Elemental analysis was performed using by energy dispersive x-ray spectroscopy (EDX). The stoichiometries measured by energy dispersive X-ray analysis were Mo1V0.32Ta0.02Te0.05Ox, Mo1V0.32Ta0.02Sb0.05Ox, and Mo1V0.33Ta0.04Bi0.05Ox.

[0143] Power 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. PXRD analysis was performed on the MoaVbTecTaaOx and MoaVbBicTaaOx samples following calcination and the results are presented in Figures 2A and 2B, respectively. By PXRD, both samples were characterized as a doped molybdenum vanadium oxide phase.

[0144] Catalysts with the formula MoaVbSbcTaaOx can also be generated using the procedure described above.

[0145] Example 2 - Catalytic Activity Measurements

[0146] MoaVbTecTadOx and MoaVbBicTaaOx prepared in Example 1 were tested for their ability to catalyze the oxidative dehydrogenation (ODH) of ethane using a microreactor unit (MRU). The MRU had 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 had 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 8890 “hot gas” Gas Chromatograph (HGGC) during times when product gas analysis was required.

[0147] The catalyst bed was loaded in the middle zone of the reactor and the remaining volume of the reactor was packed with quartz sand to produce the catalyst bed volume of 6 mb to ensure the catalyst volume was sufficient to cover measuring points 2 to 5 of a 6-point thermocouple. The reactor loading was then secured with glass wool on both the top and the bottom of the reactor.

[0148] For catalytic testing, the samples were pressed into pellets using a steel die and hydraulic press, then the pellet was pulverized and particle sizes of 425 - 710 pm were sieved out for loading into the tubular reactor. Approximately 2 g of sample (which is catalyst active phase) was placed in the reactor under a target gas flow rate of 150 seem (weight hourly space velocity (WHSV) = 3.57 h'1) and a target pressure of 20 psig. The target gas feed composition was 20 mol. % ethane, 10 mol. % oxygen and 70 mol. % nitrogen for all testing. Gas composition was determined by gas chromatography (GC) using an Agilent 6890N Gas Chromatograph, and analyzed using Chrom Perfect - Analysis, Version 6.1.10 for data evaluation. The target pressure was 20 psig at the inlet of the reactor. Flow rates of the gas feed were varied for testing. Gas composition was determined by gas chromatography (GC) using an Agilent 6890N Gas Chromatograph, and analyzed using Chrom Perfect - Analysis, Version 6. 1.10 for data evaluation. Samples were left on stream at temperature between 380 and 420°C until data appeared to equilibrate, which was approximately 5 days. No catalyst support was used.

[0149] For the MRU experiments, the gaseous product exiting the catalyst bed was directed to a vent during runs. When the gaseous product was analyzed, it was momentarily redirected to the gas chromatography unit to determine the percent of ethane, ethylene, O2, CO2, CO, and, optionally, acetic acid by gas chromatography.

[0150] 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 formula: where X is the molar concentration of the corresponding compound in the gaseous effluent exiting the reactor at the corresponding temperature. For all the experiments, the acetic acid molar concentration was assumed to be 0 mol. %, since it could not be measured at the time. The acetic acid mole fraction in the product stream was calculated based on mass balance algorithm shown in Figures 3 A and 3B.

[0151] Furthermore, the condensable portion of the product from the reactor was condensed (mainly water and acetic acid) and the non-condensable portion 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) and acetic acid (SAcetic Acid) were determined using equations (4) and (5), respectively, described above.

[0152] To close the mass balance for ODH experiments based the GC analysis of non- condensable products from the reactor, an assumption was made that that all non-condensable gaseous products behaved as ideal gases. The ideal gas equation of state is accurate in prediction of gas mixture behavior at operating pressures close to 1 atm -absolute. In the ODH experiments, the product gas samples were collected and injected to a lab GC at operating pressures 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 2 were assumed in order to calculate formed amounts of condensable products. Table 2: Chemical Reaction Assumptions

[0153] Based on the reactions shown in table 2, the mass balance methodology shown in Figures 3A-3B was used in MS Excel. The black box in Figure 3B indicates return to the black box in Figure 3A.

[0154] Example 3 - Product Selectivity as a Function of GHSV and Linear Velocity for MoaVbTecTadOx

[0155] Using the methods of Example 2, on the MoaVbTecTadOx catalyst, the GHSV and linear velocity of the bed were varied in the range of 4776 h'1to 14144 h'1and 23 cm / sec to 67 cm / sec, respectively. The product selectivity and reactant conversion as a function of

[0156] GHSV and linear velocity were measured and are shown in Figures 4A and 4B, respectively.

[0157] The results showed that increasing the GHSV or linear velocity in the tested range led to increasing selectivity towards ethylene, decreasing selectivity towards acetic acid, relatively no change in selectivity towards carbon dioxide, a relatively small increase in the selectivity to carbon monoxide, and a relatively minor decrease in the conversion of ethane.

[0158] Due to the relatively small change in the ethane conversion (58.57 ± 2.0 %), it is believed that the trend of change in product selectivity would remain the same if the reactor temperature was adjusted such that the ethane conversion remained constant for all experimental points.

[0159] Example 4 - Product Selectivity as a Function of GHSV and Linear Velocity for MoaVbBicTadOx

[0160] Using the methods of Example 2, on the MoaVbBicTadOx catalyst, the GHSV and linear velocity of the bed were varied in the range of 4714 h'1to 28266 h'1and 22 cm / sec to 136 cm / sec, respectively. The product selectivity and reactant conversion as a function of GHSV and linear velocity were measured and are shown in Figures 5A and 5B, respectively.

[0161] The results showed that increasing in GHSV or linear velocity in the mentioned range led to increasing selectivity towards ethylene, decreasing selectivity towards acetic acid, relatively no change in selectivity towards carbon dioxide, a decrease in the selectivity to carbon monoxide, and a decrease in the conversion of ethane.

[0162] Due to the relatively small change in the ethane conversion (34.9 ± 4.5%), it is believed that the trend of change in product selectivity would remain the same if the reactor temperature was adjusted such that the ethane conversion remained constant for all experimental points.

[0163] Example 5 - MoaVbTecNbdOx (Comparative Example)

[0164] Molybdenum trioxide, vanadium pentoxide, tellurium dioxide, oxalic acid dihydrate, polyethylene glycol 1000, MOWIOL® 8-88 and poly(acrylic acid) were all purchased from Sigma- Aldrich. Alpha alumina was purchased from Fisher Scientific Canada. Niobium pentoxide hydrate was purchased from Companhia Brasileira de Metalurgia e Mincracao. All chemicals were used without further purification. All water used was distilled deionized water.

[0165] MoaVbTecNbdOx was synthesized using the amounts of reagents listed in Table 3. All solid components were added to a blender and mixed for 1 -minute pulses three times to pulverize and blend the solids, shaking and tapping the sides of the container between pulses. The solid mixture was then transferred to a 40 mb vial, after which water was added and the mixture was stirred to form an orange slurry. The vial was then placed into a 2 L steel autoclave with water filled around the outside of the vial to improve heat transfer and maintain 100% relative humidity inside the vessel. The autoclave was 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 heating was stopped and the vessel was allowed to cool back to room temperature passively over approximately 6 hours. After cooling, the autoclave was vented and the vial was removed. The orange slurry became a deep purple solid over the course of the reaction. The solid was pulverized and transferred onto a vacuum filtration setup, then was washed with water until the filtrate ran clear and colorless. The deep purple solid was then placed in an oven to dry overnight at 90°C. 32.2259 g of purple solid was obtained after drying.

[0166] Table 3, Amounts of Reagents Used to Prepare MoaVbTecNbdOx

[0167] The solid sample was then calcined under N2 flow (3.9 cm / min linear velocity at STP) in a tubular quartz furnace. The solid was heated to 600°C at a rate of 1.6°C / min, held at 600°C for 2 hours, then heating was stopped and the solid was allowed to cool passively to room temperature under N2 flow for approximately 12 hours. After calcination, a 2.45% mass loss was observed. The PXRD pattern for the sample after calcination is shown in Figure 6.

[0168] A portion of the calcined sample was then used to prepare pelleted catalyst with inert carrier. The catalyst sample (10.0050 g), alpha alumina (10.0207 g), polyethylene glycol 1000 (0.3986 g), MOWIOL 8-88 (0.6095 g) and poly(acrylic acid) (0.0230 g) were added to a 1 L beaker with 100 m of water. The mixture was heated to 90°C using an oil bath and was stirred with an overhead stirrer. Heating continued until most water had evaporated, leaving a thick purple paste. The beaker was then transferred to an oven at 90°C to dry completely overnight, leaving a hard purple solid. The solid was then pulverized using a mortar and pestle, then sieved to obtain granules between 180 - 500 pm in diameter. The granules were then fed into an autopress (Dott Bonapace CPR-6) and pressed into cylindrical pellets with approximate dimensions of 3 mm diameter and 5 mm length. The pellets were then sintered in a tubular quartz furnace by first heating under dry air flow (1.8 cm / min linear velocity at STP) to 400°C at 1.0°C / min, held at 400°C for 1 hour, then cooled back to room temperature passively over approximately 8 hours. The flow in the quartz furnace was then switched to nitrogen (3.9 cm / min linear velocity at STP), and after sufficient time was given to completely purge the air out of the furnace, the sample was heated from room temperature to 600°C at 1.6°C / min, held at 600°C for 2 hours, then allowed to passively cool to room temperature over approximately 12 hours. A mass loss of 5.24 % was observed after the sintering process. The PXRD pattern from this sample is shown in Figure 7.

[0169] For catalyst testing, these pelleted samples were pulverized with a mortar and pestle, and granules of 425 - 710 pm were sieved for use in testing. Approximately 4 g of the sample was placed in the reactor to achieve a loading of approximately 2 g of catalyst phase.

[0170] Using the methods of Example 2, on the MoaVbBicTaaOx catalyst, the GHSV and linear velocity of the bed were varied in the range of 4702 h'1to 14139 h'1and 23 cm / sec to

[0171] 63 cm / sec, respectively. The product selectivity and reactant conversion as a function of GHSV and linear velocity were measured and are shown in Figures 8A and 8B, respectively. The change in ethene and acetic acid selectivity as a function of GHSV or linear velocity was greater for other catalysts tested relative to this catalyst.

Claims

CLAIMS1. A method, comprising: selecting a first product from the group consisting of ethylene and acetic acid; selecting a gas hourly space velocity (GHSV) or linear velocity; contacting a feed stream comprising ethane and oxygen with a catalyst at the selected GHSV or linear velocity; and converting at least a portion of the ethane into the first product; wherein: the catalyst comprises a catalyst with the formula:MoaVbTecTadOx; wherein a is 1.0; b is 0.01 to 0.4; c is 0.01 to 0.2; d is 0.01 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral;MoaVbSbcTadOx; wherein a is 1.0; b is 0.01 to 0.4; c is 0.01 to 0.2; d is 0.01 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral;MoaVbTecNbdOx; wherein a is 1.0; b is 0.01 to 0.4; c is 0.01 to 0.2; d is 0.01 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral; orMoaVbBicTaaOx; wherein a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; d is 0.005 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

2. The method of claim 1, wherein: the first product is ethylene; and the GHSV is greater than 9000 h’1.

3. The method of claim 1, wherein: the first product is acetic acid; and the GHSV is less than 9000 h’1.

4. The method of claim 1, wherein: the first product is ethylene; and the GHSV is greater than 9500 h’1.

5. The method of claim 1, wherein: the first product is acetic acid; and the GHSV is less than 9500 h’1.

6. The method of claim 1, wherein: the first product is ethylene; and the linear velocity is greater than 45 cm / sec.

7. The method of claim 1, wherein: the first product is acetic acid; andthe GHSV is less than 45 cm / sec.

8. The method of claim 1, wherein: the first product is ethylene; and the GHSV is greater than 15000 h'1.

9. The method of claim 1, wherein: the first product is acetic acid; and the GHSV is less than 15000 h'1.

10. The method of claim 1, wherein: the first product is ethylene; and the linear velocity is greater than 80 cm / sec.

11. The method of claim 1, wherein: the first product is acetic acid; and the linear velocity is less than 80 cm / sec.

12. The method of claim 1, wherein: the first product is acetic acid; the catalyst comprises a catalyst with the formula MoaVbTecTadOx; the GHSV is 4776 h’1; a selectivity for ethylene is less than 75 %; and a selectivity for acetic acid is greater than 10 %.

13. The method of claim 1, wherein: the first product is ethylene; the catalyst comprises a catalyst with the formula MoaVbTecTadOx; the GHSV is 14144 h’1; a selectivity for ethylene is greater than 70 %; and a selectivity for acetic acid is less than 20 %.

14. The method of claim 1, wherein: the first product is acetic acid; the catalyst comprises a catalyst with the formula MoaVbTecTaaOy the linear velocity is 23 cm / sec; a selectivity for ethylene is less than 75 %; and a selectivity for acetic acid is greater than 10 %.

15. The method of claim 1, wherein: the first product is ethylene; the catalyst comprises a catalyst with the formula MoaVbTecTadOx;the linear velocity is about 67 cm / sec; a selectivity for ethylene is greater than 70 %; and a selectivity for acetic acid is less than 20 %.

16. The method of claim 1, wherein: the first product is acetic acid; the catalyst comprises a catalyst with the formula MoaVbBicTaaOx; the GHSV is about 4714 h’1; a selectivity for ethylene is less than 90 %; and a selectivity for acetic acid is greater than 0 %.

17. The method of claim 1, wherein: the first product is ethylene; the catalyst comprises a catalyst with the formula MoaVbBicTaaOx; the GHSV is about 28266 h’1; a selectivity for ethylene is greater than 85 %; and a selectivity for acetic acid is less than 10 %.

18. The method of claim 1, wherein: the first product is acetic acid; the catalyst comprises a catalyst with the formula MoaVbBicTaaOx; the linear velocity is about 22 cm / sec; a selectivity for ethylene is less than 80 %; and a selectivity for acetic acid is greater than 0 %.

19. The method of claim 1, wherein: the first product is ethylene; the catalyst comprises a catalyst with the formula MoaVbBicTaaOx; the linear velocity is about 136 cm / sec; a selectivity for ethylene is greater than 85 %; and a selectivity for acetic acid is less than 10 %.

20. A method, comprising: contacting a first feed stream comprising ethane and oxygen with a catalyst at a first gas hourly space velocity (GHSV) or linear velocity; converting at least a portion of the ethane into a first product; contacting a second feed stream comprising ethane and oxygen with the catalyst at a second GHSV or linear velocity; and converting at least a portion of the ethane into a second product;wherein: the second GHSV or linear velocity is different from the first GHSV or linear velocity; the first product and second product are independently selected from the group consisting of ethylene and acetic acid; the second product is different from the first product; and the catalyst comprises a catalyst with the formula:MoaVbTecTadOx; wherein a is 1.0; b is 0.01 to 0.4; c is 0.01 to 0.2; d is 0.01 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral;MoaVbSbcTadOx; wherein a is 1.0; b is 0.01 to 0.4; c is 0.01 to 0.2; d is 0.01 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral;MoaVbTecNbdOx; wherein a is 1.0; b is 0.01 to 0.4; c is 0.01 to 0.2; d is 0.01 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral; orMoaVbBicTaaOx; wherein a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; d is 0.005 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

21. The method of claim 20, wherein: the catalyst has a higher selectivity for the first product at the first GHSV or linear velocity relative to the second GHSV or linear velocity; and the catalyst has a higher selectivity for the second product at the second GHSV or linear velocity relative to the first GHSV or linear velocity.

22. The method of claim 21, wherein: the first GHSV or linear velocity is higher than the second GHSV or linear velocity; the first product comprises ethylene; and the second product comprises acetic acid.

23. The method of claim 21 , wherein: the first GHSV or linear velocity is lower than the second GHSV or linear velocity; the first product comprises acetic acid; and the second product comprises ethylene.

24. The method of claim 20, wherein: the first product is ethylene; the first GHSV is greater than 9000 h’1; the second product is acetic acid; and the second GHSV is less than 9000 h’1.

25. The method of claim 20, wherein:the first product is acetic acid; the first GHSV is less than 9000 h’1; the second product is ethylene; and the second GHSV is greater than 9000 h'1.

26. The method of claim 20, wherein: the first product is ethylene; the first linear velocity is greater than 45 cm / sec; the second product is acetic acid; and the second linear velocity is less than 45 cm / sec.

27. The method of claim 20, wherein: the first product is acetic acid; the first linear velocity is less than 45 cm / sec; the second product is ethylene; and the second linear velocity is greater than 45 cm / sec.

28. The method of claim 20, wherein: the first product is ethylene; and the first GHSV is greater than 15000 h’1; the second product is acetic acid; and the second GHSV is less than 15000 h'1.

29. The method of claim 20, wherein: the first product is acetic acid; and the first GHSV is less than 15000 h’1; the second product is ethylene; and the second GHSV is greater than 15000 h'1.

30. The method of claim 20, wherein: the first product is ethylene; the first linear velocity is greater than 80 cm / sec; the second product is acetic acid; and the second linear velocity is less than 80 cm / sec.

31. The method of claim 20, wherein: the first product is acetic acid; the first linear velocity is less than 80 cm / sec; the second product is ethylene; and the second linear velocity is greater than 80 cm / sec.

32. The method of claim 20, wherein: the catalyst comprises a catalyst with the formula MoaVbTecTadOx; the first product is ethylene and the second product is acetic acid; the first GHSV is about 14144 h’1; at the first GHSV : a selectivity for ethylene is greater than 70 %; and a selectivity for acetic acid is less than 20 %; the second GHSV is about 4776 h’1; and at the second GHSV : a selectivity for ethylene is less than 75 %; and a selectivity for acetic acid is greater than 10 %.

33. The method of claim 20, wherein: the catalyst comprises a catalyst with the formula MoaVbTecTadOx; the first product is acetic acid and the second product is ethylene; the first GHSV is about 4776 h’1; at the first GHSV : a selectivity for ethylene is less than 75 %; and a selectivity for acetic acid is greater than 10 %; the second GHSV is about 14144 h’1; and at the second GHSV : a selectivity for ethylene is greater than 70 %; and a selectivity for acetic acid is less than 20 %.

34. The method of claim 20, wherein: the catalyst comprises a catalyst with the formula MoaVbTecTadOx; the first product is ethylene and the second product is acetic acid; the first linear velocity is about 67 cm / sec; at the first linear velocity: at a selectivity for ethylene is greater than 70 %; and a selectivity for acetic acid is less than 20 %; the second linear velocity is about 23 cm / sec; and at the second linear velocity: a selectivity for ethylene is less than 75 %; and a selectivity for acetic acid is greater than 10 %.

35. The method of claim 20, wherein:the catalyst comprises a catalyst with the formula MoaVbTecTadOx; the first product is acetic acid and the second product is ethylene; the first linear velocity is about 23 cm / sec; at the first linear velocity: a selectivity for ethylene is less than 75 %; and a selectivity for acetic acid is greater than 10 %; the second linear velocity is about 67 cm / sec; and at the second linear velocity: a selectivity for ethylene is greater than 70 %; and a selectivity for acetic acid is less than 20 %.

36. The method of claim 20, wherein: the catalyst comprises a catalyst with the formula MoaVbBicTaaOx; the first product is ethylene and the second product is acetic acid; the first GHSV is about 28266 h’1; at the first GHSV : a selectivity for ethylene is greater than 85 %; and a selectivity for acetic acid is less than 10 %; the second GHSV is about 4714 h’1; and at the second GHSV : a selectivity for ethylene is less than 90 %; and a selectivity for acetic acid is greater than 0 %.

37. The method of claim 20, wherein: the catalyst comprises a catalyst with the formula MoaVbBicTaaOx; the first product is acetic acid and the second product is ethylene; the first GHSV is about 4714 h’1; at the first GHSV : a selectivity for ethylene is less than 90 %; and a selectivity for acetic acid is greater than 0 %; the second GHSV is about 28266 h’1; and at the second GHSV : a selectivity for ethylene is greater than 85 %; and a selectivity for acetic acid is less than 10 %.

38. The method of claim 20, wherein: the catalyst comprises a catalyst with the formula MoaVbBicTaaOx;the first product is ethylene and the second product is acetic acid; the first linear velocity is about 136 cm / sec; at the first linear velocity: a selectivity for ethylene is greater than 85 %; and a selectivity for acetic acid is less than 10 %; the second linear velocity is about 22 cm / sec; and at the second linear velocity: a selectivity for ethylene is less than 80 %; and a selectivity for acetic acid is greater than 0 %.

39. The method of claim 20, wherein: the catalyst comprises a catalyst with the formula MoaVbBicTaaOx; the first product is acetic acid and the second product is ethylene; the first linear velocity is about 22 cm / sec; at the first linear velocity: a selectivity for ethylene is less than 80 %; and a selectivity for acetic acid is greater than 0 %; the second linear velocity is about 136 cm / sec; and at the second linear velocity: a selectivity for ethylene is greater than 85 %; and a selectivity for acetic acid is less than 10 %.

40. The method of claim 20, wherein the first feed stream and the second feed stream are the same.

41. The method of claim 20, wherein the second feed stream comprises the first feed stream and a diluent.

42. The method of claim 20, wherein the first feed stream comprises the second feed stream and a diluent.

43. The method of claim 1, wherein the catalyst comprises a catalyst with the formula: MoaVbTecTadOx; wherein a is 1.0; b is 0.01 to 0.4; c is 0.01 to 0.2; d is 0.01 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral; or MoaVbBicTadOx; wherein a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; d is 0.005 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

44. The method of claim 1, wherein the catalyst comprises a catalyst with the formula: MoaVbTecTadOx; wherein a is 1.0; b is 0.01 to 0.4; c is 0.01 to 0.2; d is 0.01 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

45. The method of claim 1, wherein the catalyst comprises a catalyst with the formula: MoaVbBicTaaOx; wherein a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; d is 0.005 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

46. The method of claim 20, wherein the catalyst comprises a catalyst with the formula: MoaVbTecTadOx; wherein a is 1.0; b is 0.01 to 0.4; c is 0.01 to 0.2; d is 0.01 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral; or MoaVbBicTadOx; wherein a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; d is 0.005 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

47. The method of claim 20, wherein the catalyst comprises a catalyst with the formula: MoaVbTecTadOx; wherein a is 1.0; b is 0.01 to 0.4; c is 0.01 to 0.2; d is 0.01 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

48. The method of claim 20, wherein the catalyst comprises a catalyst with the formula: MoaVbBicTadOx; wherein a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; d is 0.005 to 0.1; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

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