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 with a catalyst that includes molybdenum (Mo), vanadium (V), and bismuth (Bi), using reactor space velocity.

Description

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

[0002] TECHNICAL FIELD

[0003] The disclosure relates to systems and methods to alter the ethylene and / or acetic acid selectivity in the catalytic oxidative dehydrogenation of ethane with a catalyst that includes molybdenum (Mo), vanadium (V), and bismuth (Bi), using reactor space velocity.

[0004] BACKGROUND ART

[0005] 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.

[0006] 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.

[0007] SUMMARY OF INVENTION

[0008] The disclosure relates to systems and methods to alter the ethylene and / or acetic acid selectivity in the catalytic oxidative dehydrogenation of ethane with a catalyst that includes Mo, V, and Bi, using reactor space velocity.

[0009] In a first aspect, the disclosure provides a method, including: contacting a feed stream including ethane and oxygen with a catalyst at a selected gas hourly space velocity (GHSV) or linear velocity and converting at least a portion of the ethane into a first product selected from the group consisting of ethylene and acetic acid. The catalyst includes a catalyst with the formula MoaVbBicOx; where a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0010] In some embodiments, increasing the GHSV or linear velocity increases a selectivity to ethylene.

[0011] In some embodiments, increasing the GHSV or linear velocity decreases a selectivity to acetic acid.

[0012] In some embodiments, decreasing the GHSV or linear velocity decreases a selectivity to ethylene.

[0013] In some embodiments, decreasing the GHSV or linear velocity increases a selectivity to acetic acid.

[0014] In some embodiments, the catalyst does not include detectable amounts of niobium and tantalum when measured using energy-dispersive X-ray spectroscopy.

[0015] In some embodiments, the first product includes ethylene and the GHSV is greater than about 9000 h’1.

[0016] In some embodiments, the first product includes acetic acid and the GHSV is less than about 9000 h’1.

[0017] In some embodiments, the first product includes ethylene and the GHSV is greater than about 9500 h’1.

[0018] In some embodiments, the first product includes acetic acid and the GHSV is less than about 9500 h’1.

[0019] In some embodiments, the first product includes ethylene and the linear velocity is greater than about 45 cm / sec.

[0020] In some embodiments, the first product includes acetic acid and the GHSV is less than about 45 cm / sec.

[0021] In some embodiments, the first product includes ethylene and the GHSV is greater than about 15000 h’1.

[0022] In some embodiments, the first product includes acetic acid and the GHSV is less than about 15000 h’1.

[0023] In some embodiments, the first product is ethylene and the linear velocity is greater than about 80 cm / sec.

[0024] In some embodiments, the first product is acetic acid and the linear velocity is less than about 80 cm / sec. In some embodiments, the first product includes acetic acid, the GHSV is about 4716 h’1, a selectivity for ethylene is less than about 84.6%, and a selectivity for acetic acid is greater than about 9.1%.

[0025] In some embodiments, the first product includes ethylene, the GHSV is about 4716 h’1, a selectivity for ethylene is greater than about 84.6%, and a selectivity for acetic acid is less than about 9.1%.

[0026] In some embodiments, the first product includes ethylene, the GHSV is about 9431 h’1, a selectivity for ethylene is greater than about 85.9%, and a selectivity for acetic acid is less than about 6.9%.

[0027] In some embodiments, the first product includes ethylene, the GHSV is about 14150 h’1, a selectivity for ethylene is greater than about 86.8%, and a selectivity for acetic acid is less than about 4.9%.

[0028] In some embodiments, the first product includes ethylene, the GHSV is about 18866 h’1, a selectivity for ethylene is greater than about 87.3%, and a selectivity for acetic acid is less than about 3.9%.

[0029] In some embodiments, the first product includes acetic acid, the linear velocity is about 23 cm / sec, a selectivity for ethylene is less than about 84.6%, and a selectivity for acetic acid is greater than about 9.1%.

[0030] In some embodiments, the first product includes ethylene, the linear velocity is about 23 cm / sec, a selectivity for ethylene is greater than about 84.6%, and a selectivity for acetic acid is less than about 9.1%.

[0031] In some embodiments, the first product includes ethylene, the linear velocity is about 45 cm / sec, a selectivity for ethylene is greater than about 85.9%, and a selectivity for acetic acid is less than about 6.9%.

[0032] In some embodiments, the first product includes ethylene, the linear velocity is about 68 cm / sec, a selectivity for ethylene is greater than about 86.8%, and a selectivity for acetic acid is less than about 4.9%.

[0033] In some embodiments, the first product includes ethylene, the linear velocity is about 91 cm / sec, a selectivity for ethylene is greater than about 87.3%, and a selectivity for acetic acid is less than about 3.9%.

[0034] 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 selected from the group consisting of ethylene and acetic acid; 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 selected from the group consisting of ethylene and acetic acid. The second GHSV or linear velocity is different from the first GHSV or linear velocity and the first product is different from the second product. The catalyst includes a catalyst with the formula MoaVbBicOx; where a is about 1.0; b is about 0.01 to about 0.5; c is about 0.005 to about 0.2; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0035] In some embodiments, the catalyst does not include detectable amounts of niobium and tantalum when measured using energy-dispersive X-ray spectroscopy.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] In some embodiments, the first product is ethylene and the second product is acetic acid; the first GHSV is about 9431 h’1; at the first GHSV: a selectivity for ethylene is greater than about 85.9%, and a selectivity for acetic acid is less than about 6.9%; the second GHSV is about 4716 h’1; and at the second GHSV: a selectivity for ethylene is less than about 84.6%, and a selectivity for acetic acid is greater than about 9.1%.

[0047] In some embodiments, the first product is acetic acid and the second product is ethylene; the first GHSV is about 4716 h’1; at the first GHSV: a selectivity for ethylene is less than about 84.6%, and a selectivity for acetic acid is greater than about 9.1%; the second GHSV is about 9431 h’1; and at the second GHSV: a selectivity for ethylene is greater than about 85.9 %, and a selectivity for acetic acid is less than about 6.9%.

[0048] In some embodiments, the first product is ethylene and the second product is acetic acid; the first GHSV is about 14150 h’1; at the first GHSV: a selectivity for ethylene is greater than about 86.8%, and a selectivity for acetic acid is less than about 4.9%; the second GHSV is about 4716 h’1; and at the second GHSV: a selectivity for ethylene is less than about 84.6%, and a selectivity for acetic acid is greater than about 9.1%.

[0049] In some embodiments, the first product is acetic acid and the second product is ethylene; the first GHSV is about 4716 h’1; at the first GHSV: a selectivity for ethylene is less than about 84.6%, and a selectivity for acetic acid is greater than about 9.1%; the second GHSV is about 14150 h’1; and at the second GHSV: a selectivity for ethylene is greater than about 86.8%, and a selectivity for acetic acid is less than about 4.9%.

[0050] In some embodiments, the first product is ethylene and the second product is acetic acid; the first GHSV is about 18866 h’1; at the first GHSV: at a selectivity for ethylene is greater than about 87.3%, and a selectivity for acetic acid is less than about 3.9%; the second GHSV is about 4716 h’1; and at the second GHSV: a selectivity for ethylene is less than about 84.6%, and a selectivity for acetic acid is greater than about 4.9%. In some embodiments, the first product is acetic acid and the second product is ethylene; the first GHSV is about 4716 h’1; at the first GHSV: a selectivity for ethylene is less than about 84.6%, and a selectivity for acetic acid is greater than about 4.9%; the second GHSV is about 18866 h’1; and at the second GHSV: a selectivity for ethylene is greater than about 87.3%, and a selectivity for acetic acid is less than about 3.9%.

[0051] In some embodiments, the first product is ethylene and the second product is acetic acid; the first linear velocity is about 45 cm / sec; at the first linear velocity: a selectivity for ethylene is greater than about 85.9%, and a selectivity for acetic acid is less than about 6.9%; the second linear velocity is about 23 cm / sec; and at the second linear velocity: a selectivity for ethylene is less than about 84.6%, and a selectivity for acetic acid is greater than about 9.1%.

[0052] In some embodiments, 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 84.6%, and a selectivity for acetic acid is greater than about 9.1%; the second linear velocity is about 45 cm / sec; and at the second linear velocity: a selectivity for ethylene is greater than about 85.9%, and a selectivity for acetic acid is less than about 6.9%.

[0053] In some embodiments, the first product is ethylene and the second product is acetic acid; the first linear velocity is about 68 cm / sec; at the first linear velocity: a selectivity for ethylene is greater than about 86.8%, and a selectivity for acetic acid is less than about 4.9%; the second linear velocity is about 23 cm / sec; and at the second linear velocity: a selectivity for ethylene is less than about 84.6%, and a selectivity for acetic acid is greater than about 9.1%.

[0054] In some embodiments, 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 84.6%, and a selectivity for acetic acid is greater than about 9.1%; the second linear velocity is about 68 cm / sec; and at the second linear velocity: a selectivity for ethylene is greater than about 86.8%, and a selectivity for acetic acid is less than about 4.9%.

[0055] In some embodiments, the first product is ethylene and the second product is acetic acid; the first linear velocity is about 91 cm / sec; at the first linear velocity: at a selectivity for ethylene is greater than about 87.3%, and a selectivity for acetic acid is less than about 3.9%; the second linear velocity is about 23 cm / sec; and at the second linear velocity: a selectivity for ethylene is less than about 84.6%, and a selectivity for acetic acid is greater than about 4.9%.

[0056] In some embodiments, 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 84.6%, and a selectivity for acetic acid is greater than about 4.9%; the second linear velocity is about 91 cm / sec; and at the second linear velocity: a selectivity for ethylene is greater than about 87.3%, and a selectivity for acetic acid is less than about 3.9%.

[0057] In some embodiments, the first feed stream and the second feed stream are the same.

[0058] In some embodiments, the second feed stream includes the first feed stream and a diluent.

[0059] In some embodiments, the first feed stream includes the second feed stream and a diluent.

[0060] In a third aspect, the disclosure provides a method, including: contacting a feed stream including ethane and oxygen with a catalyst at a GHSV of at least 9000 h'1or a linear velocity of at least 45 cm / sec and converting at least a portion of the ethane into ethylene. The catalyst includes a catalyst with the formula MoaVbBicOx; where a is about 1.0; b is about 0.01 to about 0.5; c is about 0.005 to about 0.2; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0061] In some embodiments, the catalyst does not include detectable amounts of niobium and tantalum when measured using energy-dispersive X-ray spectroscopy.

[0062] DESCRIPTION OF DRAWINGS

[0063] Figure 1 shows a schematic for a reactor.

[0064] Figure 2 shows a powder X-ray diffraction (PXRD) plot of a catalyst.

[0065] Figure 3 shows a graph of PXRD results of a pelletized catalyst with alumina.

[0066] Figures 4A-4B depict a flowchart of a mass balance method.

[0067] Figure 5A shows a graph of product selectivity as a function of gas hourly space velocity (GHSV).

[0068] Figure 5B shows a graph of product selectivity as a function of linear velocity.

[0069] DESCRIPTION OF EMBODIMENTS

[0070] 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. 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.

[0071] The systems and methods of the present disclosure can reduce the reactor size used for ODH reactions 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.

[0072] 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.

[0073] Definitions

[0074] 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. 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%, l.l% 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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. Systems and Methods to Alter the Ethylene and / or Acetic Acid Yield in the Catalytic Oxidative Dehydrogenation of Ethane Using the Reactor Space Velocity

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] In some embodiments, the catalyst 1020 is a catalyst with the formula MoaVbBicOx; where a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0084] 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.

[0085] 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.

[0086] In some embodiments, the catalyst 1020 is a catalyst with the formula MoaVbBicOx; where a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0087] A method of the disclosure can include contacting a feed stream comprising ethane and oxygen with a catalyst at a GHSV of at least 9000 h'1or a linear velocity of at least 45 cm / s and converting at least a portion of the ethane into ethylene.

[0088] In some embodiments, the catalyst 1020 is a catalyst with the formula MoaVbBicOx; where a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral. Catalysts

[0089] In some embodiments, the catalyst 1020 contains molybdenum (Mo); vanadium (V); Bismuth (Bi); and oxygen (O). In some embodiments, the catalyst does not include detectable amounts of niobium (Nb) and tantalum (Ta) when measured using energy- dispersive X-ray spectroscopy. In some embodiments, the catalyst 1020 consists essentially of or consists of molybdenum (Mo); vanadium (V); Bismuth (Bi); and oxygen (O).

[0090] In some embodiments, the catalyst 1020 is a catalyst with the formula MoaVbBicOx; where a is 1.0; b is 0.01 to 0.5; c is 0.005 to 0.2; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

[0091] In some embodiments, a, b, and c are determined by one or both of the amount of each starting material used to form the catalyst and elemental analysis. In some embodiments, the catalyst has a powder X-ray diffraction (PXRD) pattern including at least five peaks at 20 values chosen from 7.8 ± 0.2°, 8.9 ± 0.2°, 12.7° ± 0.2°, 22.1 ± 0.2°, 23.3 ± 0.2°, 25.7° ± 0.2°, 27.2° ± 0.2°, 28.0 ± 0.2°, 29. 1 ± 0.2°, and 39.0° ± 0.2°, wherein the PXRD pattern is obtained using Cu Ka radiation.

[0092] In some embodiments, b is 0.01 to 0.5. In some embodiments, b is 0.2 to 0.4. In some embodiments, b is 0.25 to 0.35. In some embodiments, b is 0.3.

[0093] In some embodiments, c is 0.005 to 0.2. In some embodiments, c is 0.01 to 0.1. In some embodiments, c is 0.01 to 0.07. In some embodiments, c is 0.04 to 0.07. In some embodiments, c is 0.05. In some embodiments, c is 0.06.

[0094] In some embodiments, the catalyst includes the formula Mo1V0.20-0.40Bi0.01-0.07Ox. In some embodiments, the catalyst includes the formula Mo1V0.30-0.35Bi0.04-0.05Ox. In some embodiments, the catalyst includes the formula M01Vo.35Bio.05Ox or M01Vo.35Bio.06Ox.

[0095] In some embodiments, the catalyst 1020 is a catalyst that includes Mo, V, Bi, and O described in U.S. Provisional Application No. 63 / 631,685, which is herein incorporated by reference in its entirety.

[0096] Methods to prepare catalysts 1020 are described in U.S. Provisional Application No. 63 / 631,685.

[0097] In some embodiments, the catalysts are combined with an inert carrier and / or pelleted before measurement.

[0098] GHSV and Uinear Velocity

[0099] In some embodiments, to form ethylene with the catalyst MoaVbBicOx, the GHSV is at least about 500 h'1(e.g., at least about 1000, at least about 2000, at least about 3000, at least about 4000, at least about 4716, at least about 5000, at least about 6000, at least about 7000, at least about 8000, at least about 9000, at least 9431, at least about 10000, at least about 11000, at least about 12000, at least about 13000, at least about 14000, at least about 14150, at least about 15000, at least about 16000, at least about 17000, at least about 18000, at least 18866, or at least 19000 h'1) and / or at most about 20000 h'1(e.g., at most about 19000, at most about 18866, at most about 18000, at most about 17000, at most about

[0100] 16000, at most about 15000, at most about 14150, at most about 14000, at most about

[0101] 13000, at most about 12000, at most about 11000, at most about 10000, at most about 9431, at most about 9000, at most about 8000, at most about 7000, at most about 6000, at most about 5000, at most about 4716, at most about 4000, at most about 3000, at most about 2000, or at most about 1000 h'1). Without wishing to be bound by theory, it is believed that increasing GHSV leads to an increase in ethylene selectivity.

[0102] In some embodiments, to form acetic acid with the catalyst MoaVbBicOx, the GHSV is at least about 500 h'1(e.g., at least about 1000, at least about 2000, at least about 3000, at least about 4000, at least about 4716, at least about 5000, at least about 6000, at least about 7000, at least about 8000, at least about 9000, at least 9431, at least about 10000, at least about 11000, at least about 12000, at least about 13000, at least about 14000, at least about 14150, at least about 15000, at least about 16000, at least about 17000, at least about 18000, at least 18866, or at least 19000 h'1) and / or at most about 20000 h'1(e.g., at most about 19000, at most about 18866, at most about 18000, at most about 17000, at most about 16000, at most about 15000, at most about 14150, at most about 14000, at most about 13000, at most about 12000, at most about 11000, at most about 10000, at most about 9431, at most about 9000, at most about 8000, at most about 7000, at most about 6000, at most about 5000, at most about 4716, at most about 4000, at most about 3000, at most about 2000, or at most about 1000 h'1).

[0103] In some embodiments, at a GHSV of about 4716 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for ethylene of at least about 84.4% (e.g., at least about 84.5, or at least about 84.6%) and / or at most about 84.7% (e.g., at most about 84.6, or at most about 84.5%). In some embodiments, at a GHSV of about 4716 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for ethylene of about 84.6%.

[0104] In some embodiments, at a GHSV of about 4716 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for acetic acid of at least about 8.9% (at least about 9.0, at least about 9.1, at least about 9.2, or at least about 9.3%) and / or at most about 9.4% (e.g., at most about 9.3, at most about 9.2, at most about 9.1, or at most about 9.0%). In some embodiments, at a GHSV of about 4716 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for acetic acid of about 9.1%.

[0105] In some embodiments, at a GHSV of about 9431 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for ethylene of at least about 85.5% (e.g. at least about 85.6, at least about 85.7, at least about 85.8, at least about 85.9, or at least about 86.0 %) and / or at most about 86. 1% (e.g., at most about 86.0, at most about 85.9, at most about 85.8, at most about 85.7, or at most about 85.6%). In some embodiments, at a GHSV of about 9431 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for ethylene of about 85.9%.

[0106] In some embodiments, at a GHSV of about 9431 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for acetic acid of at least about 6.5% (e.g., 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, or at least about 7.4%) and / or at most about 7.5% (e.g., at most about 7.4, at most about 7.3, at most about 7.2, at most about 7.1, at most about 7.0, at most about 6.9, at most about 6.8, at most about 6.7, or at most about 6.6%). In some embodiments, at a GHSV of about 9431 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for acetic acid of about 6.9%.

[0107] In some embodiments, at a GHSV of about 14150 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for ethylene of at least about 86.6% (e.g., at least about 86.7, at least about 86.8, or at least about 86.9%) and / or at most about 87.0% (e.g., at most about 86.9, at most about 86.8, or at most about 86.7%). In some embodiments, at a GHSV of about 14150 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for ethylene of about 86.8%.

[0108] In some embodiments, at a GHSV of about 14150 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for acetic acid of at least about 4.7% (e.g., at least about 4.8, at least about 4.9, or at least about 5.0%) and / or at most about 5.1% (e.g., at most about 5.0, at most about 4.9, or at most about 4.8%). In some embodiments, at a GHSV of about 14150 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for acetic acid of about 4.9%.

[0109] In some embodiments, at a GHSV of about 18866 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for ethylene of about 87.3%.

[0110] In some embodiments, at a GHSV of about 18866 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for acetic acid of about 3.8%. In some embodiments, at a GHSV of about 18866 h’1, a catalyst with the formula MoaVbBicOx has a selectivity for acetic acid of about 3.9%.

[0111] In some embodiments, to form ethylene with the catalyst MoaVbBicOx, the linear velocity is at least about 2 cm / sec (e.g., at least about 5, at least about 10, at least about 15, at least about 20, 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, or at least about 90 cm / sec) and / or at most about 95 cm / sec (e.g., 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, at most about 20, at most about 15, at most about 10, or at most about 5 cm / sec). Without wishing to be bound by theory, it is believed that increasing the linear velocity increases the ethylene selectivity.

[0112] In some embodiments, to form acetic acid with the catalyst MoaVbBicOx, the linear velocity is at least about 2 cm / sec (e.g., at least about 5, at least about 10, at least about 15, at least about 20, 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, or at least about 90) cm / sec and / or at most about 95 cm / sec (e.g., 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, at most about 20, at most about 15, at most about 10, or at most about 5 cm / sec).

[0113] In some embodiments, at a linear velocity of about 23 cm / sec, a catalyst with the formula MoaVbBicOx has a selectivity for ethylene of at least about 84.4% (e.g., at least about 84.5, or at least about 84.6%) and / or at most about 84.7% (e.g., at most about 84.6, or at most about 84.5%). In some embodiments, at a linear velocity of about 23 cm / sec, a catalyst with the formula MoaVbBicOx has a selectivity for ethylene of about 84.6%.

[0114] In some embodiments, at a linear velocity of about 23 cm / sec, a catalyst with the formula MoaVbBicOx has a selectivity for acetic acid of at least about 8.9% (at least about 9.0, at least about 9.1, at least about 9.2, or at least about 9.3%) and / or at most about 9.4% (e.g., at most about 9.3, at most about 9.2, at most about 9.1, or at most about 9.0%). In some embodiments, at a linear velocity of about 23 cm / sec, a catalyst with the formula MoaVbBicOx can has selectivity for acetic acid of about 9.1%.

[0115] In some embodiments, at a linear velocity of about 45 cm / sec, a catalyst with the formula MoaVbBicOx has a selectivity for ethylene of at least about 85.5% (e.g. at least about 85.6, at least about 85.7, at least about 85.8, at least about 85.9, or at least about 86.0%) and / or at most about 86. 1% (e.g., at most about 86.0, at most about 85.9, at most about 85.8, at most about 85.7, or at most about 85.6%). In some embodiments, at a linear velocity of about 45 cm / sec, a catalyst with the formula MoaVbBicOx has a selectivity for ethylene of about 85.9%.

[0116] In some embodiments, at a linear velocity of about 45 cm / sec, a catalyst with the formula MoaVbBicOx has a selectivity for acetic acid of at least about 6.5% (e.g., 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, or at least about 7.4%) and / or at most about 7.5% (e.g., at most about 7.4, at most about 7.3, at most about 7.2, at most about 7.1, at most about 7.0, at most about 6.9, at most about 6.8, at most about 6.7, or at most about 6.6%). In some embodiments, at a linear velocity of about 45 cm / sec, a catalyst with the formula MoaVbBicOx can has selectivity for acetic acid of about 6.9%. In some embodiments, at a linear velocity of about 68 cm / sec, a catalyst with the formula MoaVbBicOx has a selectivity for ethylene of at least about 86.6% (e.g., at least about 86.7, at least about 86.8, or at least about 86.9%) and / or at most about 87.0% (e.g., at most about 86.9, at most about 86.8, or at most about 86.7%). In some embodiments, at a linear velocity of about 68 cm / sec, a catalyst with the formula MoaVbBicOx has a selectivity for ethylene of about 86.8%.

[0117] In some embodiments, at a linear velocity of about 67 cm / sec, a catalyst with the formula MoaVbBicOx has a selectivity for acetic acid of at least about 4.7% (e.g., at least about 4.8, at least about 4.9, or at least about 5.0%) and / or at most about 5.1% (e.g., at most about 5.0, at most about 4.9, or at most about 4.8%). In some embodiments, at a linear velocity of about 67 cm / sec, a catalyst with the formula MoaVbBicOx can has selectivity for acetic acid of about 4.9%.

[0118] In some embodiments, at a GHSV of about 91 cm / sec, a catalyst with the formula MoaVbBicOx has a selectivity for ethylene of about 87.3%.

[0119] In some embodiments, at a GHSV of about 91 cm / sec, a catalyst with the formula MoaVbBicOx has a selectivity for acetic acid of about 3.8%. In some embodiments, at a GHSV of about 91 cm / sec, a catalyst with the formula MoaVbBicOx has a selectivity for acetic acid of about 3.9%.

[0120] As used herein, the GHSV in h'1can be calculated using the equation:

[0121] GHSV =

[0122] Volumetric flow rate of feed gas and / or vapor entering the reactor or feed flow rate) at STP / . x

[0123] Volume of catalyst bed active phasev 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:

[0124] _ Fwt* 22.4 * 1000

[0125] Fvo1(2) ~ 18.02 where Fvoi is 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].

[0126] 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.

[0127] As used herein, the linear velocity in cm / sec can be calculated using the equation: Linear Velocity =

[0128] 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

[0129] (3) The void fraction of catalyst bed is the fraction of volume of the void in the catalyst bed active phase measured experimentally.

[0130] 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.

[0131] As used herein, a selectivity to acetic acid (SAcetic Acid) was determined using the following equation: where S Acetic 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. EXAMPLES

[0132] Example 1 - Synthesis and Characterization of Catalyst

[0133] All reagents were purchased from external vendors and used without further purification. Bismuth hydroxide, molybdenum(VI) oxide, vanadium(V) oxide, oxalic acid dihydrate and alpha alumina were purchased from Thermo Fisher Scientific. All water used was distilled and deionized water.

[0134] Powder X-ray diffraction (PXRD) measurements were collected using a PANalytical Empyrean X-ray diffractometer equipped with a monochromated Cu Ka source. Characterization of the samples was performed using HighScore Plus software.

[0135] The synthesis was carried out at using a 300 mL stainless-steel Parr autoclave. The oxides / hydroxides in the amounts listed in Table 1 were blended using a blender before addition of oxalic acid and water. All components were then added to a glass vial and mixed with a Teflon coated stir bar for 5 minutes before placing the vial into the autoclave, filling around the vial with ~20 mL of water, sealing and heating in a programmable oven. Additional water was added around the vial to ensure the headspace in the autoclave was at 100% relative humidity during heating. The oven was heated to 180 °C over 12 hours, held at 180°C for 48 hours then heating was stopped and the oven convectively cooled to ambient temperature over 4 hours. After cooling, the solid product was then transferred onto a vacuum filtration set up and washed with water until the filtrate ran clear and colorless. The solid was then dried in an oven at 90°C overnight. After synthesis, washing and drying, PXRD was collected on the sample (Figure 2).

[0136] Table 1. Masses of Reagents Used for Synthesis of Catalyst

[0137] Example 2 - Catalyst Formulation and Pelleting Procedure

[0138] Catalyst formulation and pelleting was conducted using a blender to mix catalyst material and inert carrier into larger granules with water. To the blender, catalyst (13.1881 g) was added and the blender was pulsed to break up larger chunks of catalyst into fine dust. Next, alpha alumina (13. 1822 g) was added, and again the blender was pulsed multiple times to generate a homogenous dust. Water (10 mb) was then added and was blended, which ended up forming a thick paste. The paste was transferred into a beaker and dried in an over overnight at 90°C.

[0139] After drying, the hard solid was gently pulverized using a mortar and pestle, then was sieved to obtain particle sizes between 180 - 500 pm (~19 g obtained). Graphite (~1 wt.%) was then added to the sieved granules as a lubricant and the mixture was shaken in a closed container to coat the granules with graphite. The sieved particles were then fed into an automatic pellet press (Dott Bonapace CPR-6) to obtain pressed cylindrical pellets with approximate dimensions of 3 mm diameter and 4.5 mm length.

[0140] Crush strength of the pelleted catalyst was tested using a Torbal FB Thor force gauge. Axial and radial crush strength measurements of cylindrical pellets were determined following ASTM D4179-22 and are listed in Table 2. PXRD was collected on the formulated sample and is shown in Figure 3.

[0141] Table 2, Axial and Radial Crush Strengths Measured for Formulated Pellets of MoaVbBicOx Catalyst with 49,5 wt. % a-AhCh and 1 wt. % Graphite

[0142] Example 3 - Catalytic Testing

[0143] The composition prepared in Example 2 was tested for catalytic activity on a Microreactor Unit (MRU). 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 was placed in the reactor under a target gas flow rate of 150 seem (WHSV = 3.57 h'1) and a target pressure of 22 psig. Before testing, the catalyst was pretreated in the reactor under nitrogen flow (WHSV = 3.57 h'1) by heating to 450°C for two hours. After, the sample was cooled, the target gas feed composition was 20 mol. % ethane, 10 mol. % oxygen and 70 mol. % nitrogen for all subsequent 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.

[0144] For the MRU experiments the gaseous product exiting the catalyst bed was directed to vent during runs. When the gaseous product was to be analyzed, it was momentarily redirected to a gas chromatography unit to determine the percent of ethane, ethylene, O2, CO2, CO, and, optionally, acetic acid. The gas exiting the reactor was analyzed by gas chromatography. 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 corresponding temperature. For all the experiments, 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 4A and 4B.

[0145] 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) was determined using equation (4) above.

[0146] In order to close the mass balance for ODH experiments based on GC analysis of non-condensable product from the reactor, an assumption was made that that all non- condensable gaseous products behave as ideal gases. The ideal gas equation of state is accurate in prediction of gas mixture behavior at operating pressure close to 1 atm absolute. Because in ODH experiments, the product gas samples were collected and injected to a lab GC at operating pressure close to 1 atm absolute, the ideal gas behavior assumption is expected to generate accurate prediction of the gas mixture behavior. The following bulk chemical reactions were assumed in order to calculate formed amounts of condensable products: Table 3 , Chemical Reaction Assumptions

[0147] Based on the reactions shown in Table 3, the mass balance methodology shown in Figures 4A-4B was used in MS Excel. The black box in Figure 4B indicates return to the black box in Figure 4A.

[0148] The GHSV and linear velocity of the bed were varied in the range of 4716 h'1to 18866 h'1and 23 cm / sec to 91 cm / sec, respectively. The product selectivity as a function of GHSV and linear velocity were measured and are shown in Figures 5A and 5B, respectively. The ethane conversion was 50.9 ± 0.7 % and was essentially constant across the GHSVs and linear velocities tested. The results show that the increase in GHSV or linear velocity in the tested range led to an increase in ethylene selectivity, a decrease in acetic acid selectivity, a minor increase in CO2 selectivity, and a minor increase in CO selectivity.

Claims

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

2. The method of claim 1, wherein increasing the GHSV or linear velocity increases a selectivity to ethylene.

3. The method of claim 1, wherein increasing the GHSV or linear velocity decreases a selectivity to acetic acid.

4. The method of claim 1, wherein decreasing the GHSV or linear velocity decreases a selectivity to ethylene.

5. The method of claim 1, wherein decreasing the GHSV or linear velocity increases a selectivity to acetic acid.

6. The method of claim 1, wherein the catalyst does not include detectable amounts of niobium and tantalum when measured using energy-dispersive X-ray spectroscopy.

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

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

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

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

11. The method of claim 1, wherein: the first product comprises ethylene; andthe linear velocity is greater than about 45 cm / sec.

12. The method of claim 1, wherein: the first product comprises acetic acid; and the GHSV is less than about 45 cm / sec.

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

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

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

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

17. The method of claim 1, wherein: the first product comprises acetic acid; the GHSV is about 4716 h’1; a selectivity for ethylene is less than about 84.6%; and a selectivity for acetic acid is greater than about 9.1%.

18. The method of claim 1, wherein: the first product comprises ethylene; the GHSV is about 4716 h’1; a selectivity for ethylene is greater than about 84.6%; and a selectivity for acetic acid is less than about 9.1%.

19. The method of claim 1, wherein: the first product comprises ethylene; the GHSV is about 9431 h’1; a selectivity for ethylene is greater than about 85.9%; and a selectivity for acetic acid is less than about 6.9%.

20. The method of claim 1, wherein: the first product comprises ethylene; the GHSV is about 14150 h’1;a selectivity for ethylene is greater than about 86.8%; and a selectivity for acetic acid is less than about 4.9%.

21. The method of claim 1, wherein: the first product comprises ethylene; the GHSV is about 18866 h’1; a selectivity for ethylene is greater than about 87.3%; and a selectivity for acetic acid is less than about 3.9%.

22. The method of claim 1, wherein: the first product comprises acetic acid; the linear velocity is about 23 cm / sec; a selectivity for ethylene is less than about 84.6%; and a selectivity for acetic acid is greater than about 9.1%.

23. The method of claim 1, wherein: the first product comprises ethylene; the linear velocity is about 23 cm / sec; a selectivity for ethylene is greater than about 84.6%; and a selectivity for acetic acid is less than about 9.1%.

24. The method of claim 1, wherein: the first product comprises ethylene; the linear velocity is about 45 cm / sec; a selectivity for ethylene is greater than about 85.9%; and a selectivity for acetic acid is less than about 6.9%.

25. The method of claim 1, wherein: the first product comprises ethylene; the linear velocity is about 68 cm / sec; a selectivity for ethylene is greater than about 86.8%; and a selectivity for acetic acid is less than about 4.9%.

26. The method of claim 1, wherein: the first product comprises ethylene; the linear velocity is about 91 cm / sec; a selectivity for ethylene is greater than about 87.3%; and a selectivity for acetic acid is less than about 3.9%.

27. 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 selected from the group consisting of ethylene and acetic acid; 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 selected from the group consisting of ethylene and acetic acid; wherein: the second GHSV or linear velocity is different from the first GHSV or linear velocity; the first product is different from the second product; and the catalyst comprises a catalyst with the formula MoaVbBicOx; wherein a is about 1.0; b is about 0.01 to about 0.5; c is about 0.005 to about 0.2; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

28. The method of claim 27, wherein the catalyst does not include detectable amounts of niobium and tantalum when measured using energy-dispersive X-ray spectroscopy.

29. The method of claim 27, 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.

30. The method of claim 29, 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.

31. The method of claim 29, 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.

32. The method of claim 27, wherein: the first product is ethylene; the first GHSV is greater than about 9000 h’1; the second product is acetic acid; andthe second GHSV is less than about 9000 h'1.

33. The method of claim 27, wherein: 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.

34. The method of claim 27, wherein: 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.

35. The method of claim 27, wherein: 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.

36. The method of claim 27, wherein: the first product is ethylene; and 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.

37. The method of claim 27, wherein: the first product is acetic acid; and 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.

38. The method of claim 27, wherein: 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.

39. The method of claim 27, wherein: 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.

40. The method of claim 27, wherein: the first product is ethylene and the second product is acetic acid; the first GHSV is about 9431 h’1; at the first GHSV : a selectivity for ethylene is greater than about 85.9%; and a selectivity for acetic acid is less than about 6.9%; the second GHSV is about 4716 h’1; and at the second GHSV : a selectivity for ethylene is less than about 84.6%; and a selectivity for acetic acid is greater than about 9.1%.

41. The method of claim 27, wherein: the first product is acetic acid and the second product is ethylene; the first GHSV is about 4716 h’1; at the first GHSV : a selectivity for ethylene is less than about 84.6%; and a selectivity for acetic acid is greater than about 9.1%; the second GHSV is about 9431 h’1; and at the second GHSV : a selectivity for ethylene is greater than about 85.9%; and a selectivity for acetic acid is less than about 6.9%.

42. The method of claim 27, wherein: the first product is ethylene and the second product is acetic acid; the first GHSV is about 14150 h’1; at the first GHSV : a selectivity for ethylene is greater than about 86.8%; and a selectivity for acetic acid is less than about 4.9%; the second GHSV is about 4716 h’1; and at the second GHSV : a selectivity for ethylene is less than about 84.6%; and a selectivity for acetic acid is greater than about 9.1%.

43. The method of claim 27, wherein: the first product is acetic acid and the second product is ethylene;the first GHSV is about 4716 h’1; at the first GHSV : a selectivity for ethylene is less than about 84.6%; and a selectivity for acetic acid is greater than about 9.1%; the second GHSV is about 14150 h’1; and at the second GHSV : a selectivity for ethylene is greater than about 86.8%; and a selectivity for acetic acid is less than about 4.9%.

44. The method of claim 27, wherein: the first product is ethylene and the second product is acetic acid; the first GHSV is about 18866 h’1; at the first GHSV : at a selectivity for ethylene is greater than about 87.3%; and a selectivity for acetic acid is less than about 3.9%; the second GHSV is about 4716 h’1; and at the second GHSV : a selectivity for ethylene is less than about 84.6%; and a selectivity for acetic acid is greater than about 4.9%.

45. The method of claim 27, wherein: the first product is acetic acid and the second product is ethylene; the first GHSV is about 4716 h’1; at the first GHSV : a selectivity for ethylene is less than about 84.6%; and a selectivity for acetic acid is greater than about 4.9%; the second GHSV is about 18866 h’1; and at the second GHSV : a selectivity for ethylene is greater than about 87.3%; and a selectivity for acetic acid is less than about 3.9%.

46. The method of claim 27, wherein: the first product is ethylene and the second product is acetic acid; the first linear velocity is about 45 cm / sec; at the first linear velocity: a selectivity for ethylene is greater than about 85.9%; and a selectivity for acetic acid is less than about 6.9%;the second linear velocity is about 23 cm / sec; and at the second linear velocity: a selectivity for ethylene is less than about 84.6%; and a selectivity for acetic acid is greater than about 9.1%.

47. The method of claim 27, wherein: 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 84.6%; and a selectivity for acetic acid is greater than about 9.1%; the second linear velocity is about 45 cm / sec; and at the second linear velocity: a selectivity for ethylene is greater than about 85.9%; and a selectivity for acetic acid is less than about 6.9%.

48. The method of claim 27, wherein: the first product is ethylene and the second product is acetic acid; the first linear velocity is about 68 cm / sec; at the first linear velocity: a selectivity for ethylene is greater than about 86.8%; and a selectivity for acetic acid is less than about 4.9%; the second linear velocity is about 23 cm / sec; and at the second linear velocity: a selectivity for ethylene is less than about 84.6%; and a selectivity for acetic acid is greater than about 9.1%.

49. The method of claim 27, wherein: 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 84.6%; and a selectivity for acetic acid is greater than about 9.1%; the second linear velocity is about 68 cm / sec; and at the second linear velocity: a selectivity for ethylene is greater than about 86.8%; and a selectivity for acetic acid is less than about 4.9%.

50. The method of claim 27, wherein: the first product is ethylene and the second product is acetic acid; the first linear velocity is about 91 cm / sec; at the first linear velocity: at a selectivity for ethylene is greater than about 87.3%; and a selectivity for acetic acid is less than about 3.9%; the second linear velocity is about 23 cm / sec; and at the second linear velocity: a selectivity for ethylene is less than about 84.6%; and a selectivity for acetic acid is greater than about 4.9%.

51. The method of claim 27, wherein: 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 84.6%; and a selectivity for acetic acid is greater than about 4.9%; the second linear velocity is about 91 cm / sec; and at the second linear velocity: a selectivity for ethylene is greater than about 87.3%; and a selectivity for acetic acid is less than about 3.9%.

52. The method of claim 27, wherein the first feed stream and the second feed stream are the same.

53. The method of claim 27, wherein the second feed stream comprises the first feed stream and a diluent.

54. The method of claim 27, wherein the first feed stream comprises the second feed stream and a diluent.

55. A method, comprising: contacting a feed stream comprising ethane and oxygen with a catalyst at a GHSV of at least 9000 h'1or a linear velocity of at least 45 cm / sec; and converting at least a portion of the ethane into ethylene. wherein the catalyst comprises a catalyst with the formula MoaVbBicOx; wherein a is about 1.0; b is about 0.01 to about 0.5; c is about 0.005 to about 0.2; and x is the number of oxygen atoms necessary to render the catalyst electrically neutral.

56. The method of claim 55, wherein the catalyst does not include detectable amounts of niobium and tantalum when measured using energy-dispersive X-ray spectroscopy.

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