Catalyst and process for dehydrogenation of alkanes to olefins

Abstract

< TableDetails number = '0001' > < Title / > < tbl: tgroup cool = '2' > < tbl: colspec cool = 'c001' cool width = '50%' / > < tbl: colspec cool width = 'c002' cool width = '1' > 2 theta (+ / -0.3 DEG) < / tbl: entry > < tbl: entry = '1' > relative

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority from European patent application 23382182.6, filed on February 28, 2023, and entitled “MIXED METAL OXIDE CATALYSTFOR DEHYDROGENATION OF ETHANE”, the entire contents of which are incorporated herein by reference. Background Art Technical Field

[0003] This specification generally relates to catalysts for the dehydrogenation of alkanes to olefins, such as catalysts for the conversion of ethane to ethylene. Background Art

[0005] Conventional catalysts for converting alkanes to olefins, such as ethane to ethylene and acetic acid, are based on molybdenum (Mo), vanadium (V), and niobium (Nb), and include promoters such as calcium (Ca), sodium (Na), antimony (Sb), or tellurium (Te). In particular, Te is a common promoter included in conventional catalysts. Processes using such catalysts require an oxygen co-feed and utilize oxidative dehydrogenation processes at low temperatures, such as below 500° C., and low pressures, such as below 300 pounds per square inch gauge (psig) (or about 20 barg). Summary of the Invention

[0006] According to one embodiment, the oxidative dehydrogenation catalyst comprises: (i) a catalyst having the formula Mo v V w A y Bi z O x a structure comprising an oxide of molybdenum (Mo), vanadium (V), tungsten (W) or tantalum (Ta) and bismuth (Bi), wherein v is 1, w is 0.2 to 0.5, A is W or Ta, y is 0.001 to 0.3, z is 0.01 to 0.3, and x is the oxygen content required to balance the charge of the structure, and (ii) a crystal structure comprising a Pba2-32 space group, the crystal structure being obtained by heating the structure with Cu-K α The reflections measured by X-ray diffraction (XRD) were characterized as follows:

[0007] 2θ(±0.3°) Relative strength (%) 5.3 0.2–10 6.6 1.5–15 7.84 2.5–45 8.95 4–21 22.17 100 27.2 20–70

[0008] According to another embodiment, a method for forming an oxidative dehydrogenation catalyst comprises: adding a molybdenum-containing compound, a vanadium-containing compound, a bismuth-containing compound, a tungsten-containing compound or a tantalum-containing compound and one or more organic acids to a mixture of a complexing agent and water; synthesizing Mo by hydrothermal synthesis at a hydrothermal synthesis temperature for a certain period of time. v Vw A y Bi z O x , wherein v is 1, w is 0.2 to 0.5, A is W or Ta, y is 0.001 to 0.3, z is 0.01 to 0.3, and x is the oxygen content required to balance the charge of the structure; and separating Mo from the retained liquid v V w A y Bi z O x .

[0009] In another embodiment, a process for converting paraffins to olefins comprises: contacting a feed stream comprising paraffins with the oxidative dehydrogenation catalyst; converting at least a portion of the paraffins to olefins, thereby producing a product stream comprising paraffins and olefins; and separating the paraffins from the olefins in the product stream, wherein the oxidative dehydrogenation catalyst comprises: (i) a catalyst having the formula Mo v V w A y Bi z O x The invention relates to a structure comprising an oxide of molybdenum (Mo), vanadium (V), tungsten (W) or tantalum (Ta) and bismuth (Bi), wherein v is 1, w is 0.2 to 0.5, A is W or Ta, y is 0.001 to 0.3, z is 0.01 to 0.3, and x is the amount of oxygen required to balance the charge of the structure, and (ii) a crystal structure (Pba2-32 space group) obtained by heating the structure with Cu-K α The reflections measured by X-ray diffraction (XRD) were characterized as follows:

[0010] 2θ(±0.3°) Relative strength (%) 5.3 0.2–10 6.6 1.5–15 7.84 2.5–45 8.95 4–21 22.17 100 27.2 20–70

[0011] As one of ordinary skill in the art will recognize, relative intensities may be affected by preferential orientation effects, and the relative intensities disclosed above take such effects into account.

[0012] Additional features and advantages will be set forth in the detailed description which follows, and in part will become apparent to those skilled in the art from that description or may be learned by practicing the embodiments described herein, including the following detailed description and claims.

[0013] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. DETAILED DESCRIPTION

[0014] Reference will now be made in detail to embodiments of catalysts for the dehydrogenation of alkanes to olefins, such as catalysts for the conversion of ethane to ethylene, and methods for preparing such catalysts.

[0015] A problem with conventional oxidative dehydrogenation methods is that they require a co-feed stream of oxygen (O 2 ). This increases the cost of the method due to the need to produce pure or almost pure oxygen for the equipment used in the method. In addition, since oxygen and hydrocarbons mix, the presence of oxygen in the method increases the probability of undesirable dangerous combustion. Conventional catalysts also need to have a certain amount of oxygen to keep the catalyst stable. In addition, the oxidative dehydrogenation (ODH) of hydrocarbons (such as ethane) results in the formation of olefins (such as ethylene) and H 2 O. Unfortunately, the typical catalysts used in ODH also result in the formation of undesirable by-products, such as carbon oxides and oxygenated hydrocarbons, such as acetic acid. Finally, due to the nature of the catalyst and the need for oxygen for the dehydrogenation of alkanes, the conventional oxidative dehydrogenation method for converting alkanes into alkenes is carried out in a fixed bed reactor, which requires downtime to remove and replace or regenerate the catalyst. Therefore, there is a need for an improved catalyst that can convert alkanes into alkenes. Although conventional catalysts can be used for oxidative dehydrogenation, these conventional catalysts show limited stability when operated in a cyclic redox mode or under conditions with low O2 partial pressure (typically encountered at the bottom portion of a fixed bed reactor) due to chemical changes, reduction, and volatilization of elements such as tellurium.

[0016] Surprisingly, it has been found that the composition modification of conventional oxidative dehydrogenation catalysts as disclosed and described herein allows stable reduction and oxidation (redox) circulation of materials. The catalyst disclosed and described herein has a sufficiently high oxygen carrying capacity so that the selective conversion of ethane to ethylene is achieved in a circulating reactor fed with oxygen-containing solids. By using the catalyst disclosed and described herein, industrially feasible circulation rates can be used in a circulating reactor, and sufficient conversion and selectivity of ethane to ethylene are achieved. This eliminates the need for oxygen in the reactor feed. In addition, air can be used for reoxidation of spent catalyst. In addition, the reactor / regenerator system for ethane conversion is exothermic and therefore can be operated without additional heat input.

[0017] One known oxidative dehydrogenation catalyst includes MoVNbTeO x Without being bound by any particular theory, it is believed that MoVNbTeO x , for example, a crystal phase structure of a Pba2-32 space group or a similar crystal phase structure provides a structure that can provide a desired olefin in high yield. However, using this MoVNbTeO in the oxidative dehydrogenation method xThe catalyst causes significant catalyst stability issues in reducing environments because Te is volatile under reducing conditions, leading to reactor contamination with Te and potential destruction of the catalyst's preferred crystal structure. This will subsequently lead to activity / selectivity losses during the conversion of alkanes to olefins.

[0018] In the embodiments disclosed and described herein, Te can be in the form of MoVNbTeO x The catalyst composition is completely replaced with bismuth (Bi), and Nb can be further completely replaced with tungsten (W) or tantalum (Ta). Using a specific hydrothermal synthesis method disclosed in more detail herein, the catalyst has a similar structure to MoVNbTeO x The oxidative dehydrogenation catalyst according to the embodiment has a structure comprising molybdenum (Mo), vanadium (V), tungsten (W) or tantalum (Ta) and bismuth (Bi). The oxidative dehydrogenation catalyst mainly has a Pba2-32 space group crystal structure. Volatile Te is replaced by Bi, which is different from the known MoVNbTeO x This improves material stability compared to other catalysts while providing similar alkane conversions. For example, in embodiments, the oxidative dehydrogenation catalysts disclosed and described herein are surprisingly both active (greater than 10% ethane conversion) and selective (greater than 75% ethylene selectivity) and provide stable performance under cyclic redox reaction conditions.

[0019] In one or more embodiments, the oxidative dehydrogenation catalyst has the following formula: Mo v V w A y Bi z O x, wherein v is 1.0 (e.g., Mo is used as the basis for the atomic ratio), w is 0.2 to 0.5, A is W or Ta, y is 0.001 to 0.3, z is 0.01 to 0.3, and x is the oxygen content required to balance the charge of the structure. In embodiments, w is 0.2 to 0.5, 0.3 to 0.5, 0.4 to 0.5, 0.1 to 0.4, 0.2 to 0.4, 0.3 to 0.4, 0.1 to 0.3, 0.2 to 0.3, or 0.1 to 0.2. In embodiments, y is 0.01 to 0.3, 0.05 to 0.3, 0.1 to 0.3, 0.15 to 0.3, 0.2 to 0.3, 0.25 to 0.3, 0.001 to 0.25, 0.01 to 0.25, 0.05 to 0.25, 0.1 to 0.25, 0.15 to 0.25, 0.2 to 0.25, 0.01 to 0.2, 0.05 to 0.2, 0.1 to 0.2, 0.15 to 0.2, 0.01 to 0.15, 0.05 to 0.15, 0.1 to 0.15, 0.01 to 0.1, 0.05 to 0.1, or 0.01 to 0.05. In embodiments, z is from 0.05 to 0.3, 0.10 to 0.3, 0.15 to 0.3, 0.2 to 0.3, 0.25 to 0.3, 0.01 to 0.25, 0.05 to 0.25, 0.10 to 0.25, 0.15 to 0.25, 0.2 to 0.25, 0.01 to 0.2, 0.05 to 0.2, 0.10 to 0.2, 0.15 to 0.2, 0.01 to 0.15, 0.05 to 0.15, 0.10 to 0.15, 0.01 to 0.1, 0.05 to 0.1, or 0.01 to 0.05. In embodiments, the oxidative dehydrogenation catalyst has the formula: MoV 0.3 W 0.1 Bi 0.1 O x , where x is the oxygen content required to balance the charge of the structure. In embodiments, the oxidative dehydrogenation catalyst has the formula: MoV 0.3 Ta 0.1 Bi 0.1 O x , where x is the oxygen content required to balance the charge of the structure. It should be understood that Mo v V w A y Bi z O x Embodiments of the catalyst comprise a Pba2-32 space that is substantially free of Te, such as having a Te / Mo atomic ratio less than or equal to 0.01.

[0020] It has been found that in the case of v V w A y Bi z Ox The presence of W or Ta in an oxidative dehydrogenation catalyst having a Pba2-32 space group crystal structure improves catalyst activity and selectivity in a lattice oxidative dehydrogenation process in which oxygen for conversion is extracted from the crystal lattice of the catalyst rather than through a molecular oxygen feed stream. Thus, in embodiments, the oxidative dehydrogenation catalyst comprises a catalyst having the formula Mo v V w A y Bi z O x The structure of Mo, V, W or Ta and Bi oxides and the Pba2-32 space group crystal structure are composed.

[0021] In embodiments, the crystal structure of the oxidative dehydrogenation catalysts disclosed and described herein can also be measured using X-ray diffraction (XRD). For example, and as will be appreciated by one skilled in the art, the positions and relative intensities of the XRD peaks at various 2θ angles can be used to describe the crystal structure of the oxidative dehydrogenation catalyst. In embodiments, the oxidative dehydrogenation catalyst has a Cu-K α The reflections measured by XRD are shown in Table 1. In Table 1 below, the relative intensity (relative intensity / Rel.Intensity) is maximum at 2θ=22.17°, and therefore this relative intensity is set to 100% and used as the basis for the remaining relative intensities shown in Table 1. As will be appreciated by those skilled in the art, the relative intensity may be affected by preferential orientation effects, and the relative intensities disclosed above take such effects into account.

[0022] Table 1

[0023] 2θ(±0.3°) Relative strength (%) 5.3 0.2–10 6.6 1.5–15 7.84 2.5–45 8.95 4–21 22.17 100 27.2 20–70

[0024] As described above, the use of specific hydrothermal methods to form the oxidative dehydrogenation catalyst allows for the formation of an oxidative dehydrogenation catalyst having the desired Pba2-32 crystal structure. Embodiments of these hydrothermal methods for forming the oxidative dehydrogenation catalyst will now be described in more detail.

[0025] In one or more embodiments, having Mo v V w A y Bi z O xThe oxidative dehydrogenation catalyst of the structure is formed by a synthesis method that starts by adding a molybdenum-containing compound, a vanadium-containing compound, a bismuth-containing compound, a tungsten-containing compound, or a tantalum-containing compound and one or more organic acids to a mixture of an alkylene glycol or an alcoholamine and water to form a reaction mixture. In this application, it should be understood that when "A" is used in the catalyst structure, it is intended to represent tungsten (W) or tantalum (Ta). In an embodiment, the metal precursor is selected so that the precursor can be dissolved / digested under hydrothermal reaction conditions. Mo is then synthesized from the reaction mixture by hydrothermal synthesis at a hydrothermal synthesis temperature for a certain period of time. v V w A y Bi z O x After this period of time, the Mo is separated from the retained liquid. v V w A y Bi z O x In one or more embodiments, a molybdenum-containing, vanadium-containing, bismuth-containing, tungsten-containing, or tantalum-containing compound and one or more acids are added sequentially to a mixture of an alkylene glycol and water.

[0026] In an embodiment, the bismuth-containing compound is selected from the group consisting of: bismuth oxide (Bi2O3), bismuth sulfate (Bi2(SO4)3), bismuth citrate (BiC6H5O7), bismuth molybdate (Bi2(MoO4)3), bismuth vanadate (BiVO4) and bismuth nitrate (Bi(NO3)3). In an embodiment, the tungsten-containing compound is selected from the group consisting of: tungsten trioxide (WO3), bismuth tungstate (Bi2(WO4)3) and ammonium metatungstate hydrate ((NH4)6H2W 12 O 40 In an embodiment, the tantalum-containing compound is selected from the group consisting of tantalum oxide, tantalum alkoxide, and tantalum oxalate. In an embodiment, the molybdenum-containing compound may be ammonium heptamolybdate (NH4)6Mo7O 24 or molybdenum trioxide (MoO3), and the vanadium-containing compound may be ammonium metavanadate (NH4VO3), vanadium oxysulfate (VOSO4), or vanadium pentoxide (V2O5). In embodiments, the molybdenum-containing compound and the vanadium-containing compound are MoO3 and V2O5, respectively. In some embodiments, a digestible mixture of metal-containing compounds having the correct stoichiometric ratio of one or more of Mo, V, W, or Ta and Bi may be used. Examples of such digestible mixtures include (Mo, V)O x 、BiWO x and BiTaO xIn one or more embodiments, the acid is selected from the group consisting of citric acid (C6H8O7), oxalic acid (C2H2O4), and mixtures thereof. In embodiments, the alkylene glycol is ethylene glycol.

[0027] In an embodiment, the hydrothermal synthesis temperature is 150°C to 250°C, 160°C to 250°C, 170°C to 250°C, 180°C to 250°C, 190°C to 250°C, 200°C to 250°C, 210°C to 250°C, 220°C to 250°C, 230°C to 250°C, 240°C to 250°C, 150°C to 240°C, 160°C to 240°C, 170°C to 240°C, 0℃、180℃~240℃、190℃~240℃、200℃~240℃、210℃~240℃、220℃~240℃、230℃~240℃、150℃~230℃、160℃~230℃、170℃~230℃、180℃~230℃、190℃~230℃、200℃~230℃、210℃~230℃、220℃~230 ℃, 150℃ to 220℃, 160℃ to 220℃, 170℃ to 220℃, 180℃ to 220℃, 190℃ to 220℃, 200℃ to 220℃, 210℃ to 220℃, 150℃ to 210℃, 160℃ to 210℃, 170℃ to 210℃, 180℃ to 210℃, 190℃ to 210℃, 200℃ to 210℃, 150℃ to 200℃ , 160°C to 200°C, 170°C to 200°C, 180°C to 200°C, 190°C to 200°C, 150°C to 190°C, 160°C to 190°C, 170°C to 190°C, 180°C to 190°C, 150°C to 180°C, 160°C to 180°C, 170°C to 180°C, 150°C to 170°C, 160°C to 170°C, or 150°C to 160°C.

[0028] In embodiments, the hydrothermal pressure is from 4 bar (400 kPa) to 40 bar (4000 kPa), such as from 5 bar (500 kPa) to 40 bar (4000 kPa), from 10 bar (1000 kPa) to 40 bar (4000 kPa), from 15 bar (1500 kPa) to 40 bar (4000 kPa), from 20 bar (2000 kPa) to 40 bar (4000 kPa), from 25 bar (2500 kPa) to 40 bar (4000 kPa), from 30 bar (3000 kPa) to 40 bar (4000 kPa), from 35 bar (3500 kPa) to 40 bar (4000 kPa), from 4 bar (4000 kPa), from 5 bar (5000 kPa) to 40 bar (4000 kPa), from 6 bar (6000 kPa) to 6 bar (4000 kPa), from 7 bar (7000 kPa) to 7 bar (4000 kPa), from 8 bar (7000 kPa) to 8 bar (4000 kPa), from 9 bar (8000 kPa) to 9 bar (4000 kPa), from 10 bar (1000 kPa) to 10 bar (4000 kPa), from 15 bar (1500 kPa) to 10 bar (4000 kPa), from 20 bar (2000 kPa) to 10 bar (4000 kPa), from 25 bar (2500 kPa) to 10 bar (4000 kPa), from 30 bar (3000 kPa) to 10 bar (4000 kPa), from 35 bar (3500 kPa) to 10 bar (4000 kPa), from 4 bar (40 kPa) to 35 bar (3500 kPa), 5 bar (500 kPa) to 35 bar (3500 kPa), 10 bar (1000 kPa) to 35 bar (3500 kPa), 15 bar (1500 kPa) to 35 bar (3500 kPa), 20 bar (2000 kPa) to 35 bar (3500 kPa), 25 bar (2500 kPa) to 35 bar (3500 kPa), 30 bar (3000 kPa) to 35 bar (3500 kPa), 4 bar (400 kPa) to 30 bar (3000 kPa), 5 bar (500 kPa) to 30 bar (3000 kPa), 10 bar ( 1000kPa) to 30 bar (3000kPa), 15 bar (1500kPa) to 30 bar (3000kPa), 20 bar (2000kPa) to 30 bar (3000kPa), 25 bar (2500kPa) to 30 bar (3000kPa), 4 bar (400kPa) to 25 bar (2500kPa), 5 bar (500kPa) to 25 bar (2500kPa), 10 bar (1000kPa) to 25 bar (2500kPa), 15 bar (1500kPa) to 25 bar (2500kPa), 20 bar (2000kPa) to 25 bar (2500kPa) kPa), 4 bar (400 kPa) to 20 bar (2000 kPa), 5 bar (500 kPa) to 20 bar (2000 kPa), 10 bar (1000 kPa) to 20 bar (2000 kPa), 15 bar (1500 kPa) to 20 bar (2000 kPa), 4 bar (400 kPa) to 15 bar (1500 kPa), 5 bar (500 kPa) to 15 bar (1500 kPa), 10 bar (1000 kPa) to 15 bar (1500 kPa), 4 bar (400 kPa) to 10 bar (1000 kPa), or 5 bar (500 kPa) to 10 bar (1000 kPa). In embodiments, the hydrothermal pressure is autogenous relative to the hydrothermal synthesis temperature.

[0029] According to the embodiment, when Mo v V w A yBi z O x After the oxidative dehydrogenation catalyst is separated from the retained liquid, the Mo v V w A y Bi z O x The oxidative dehydrogenation catalyst is dried and optionally added by mixing the dried Mo v V w A y Bi z O x The oxidative dehydrogenation catalyst is heated to the calcination temperature and the Mo v V w A y Bi z O x The oxidative dehydrogenation catalyst is calcined by maintaining it at the calcination temperature for a certain period of time.

[0030] In an embodiment, Mo v V w A y Bi z O x The oxidative dehydrogenation catalyst may be dried at any suitable temperature. However, to expedite drying, in embodiments, the Mo v V w A y Bi z O x The oxidative dehydrogenation catalyst may be dried at a temperature of 65°C to 200°C, 75°C to 200°C, 100°C to 200°C, 125°C to 200°C, 150°C to 200°C, 175°C to 200°C, 65°C to 175°C, 75°C to 175°C, 100°C to 175°C, 125°C to 175°C, 150°C to 175°C, 65°C to 150°C, 75°C to 150°C, 100°C to 150°C, 125°C to 150°C, 65°C to 125°C, 75°C to 125°C, 100°C to 125°C, 65°C to 100°C, 75°C to 100°C, or 65°C to 75°C.

[0031] In an embodiment, the calcination is carried out in an inert atmosphere, such as nitrogen (N2), argon (Ar) or helium (He). In such embodiments, the calcination temperature is 350°C to 650°C, 375°C to 650°C, 400°C to 650°C, 425°C to 650°C, 450°C to 650°C, 475°C to 650°C, 500°C to 650°C, 525°C to 650°C, 550°C to 650°C, 575°C to 650°C, 600°C to 650°C, 625°C to 650°C, 350°C to 625°C, 375°C to 625°C, 400°C to 625°C, 425°C to 625°C, 450°C to 625°C, 475°C to 625 ... to 625°C, 525°C to 625°C, 550°C to 625°C, 575°C to 625°C, 600°C to 625°C, 350°C to 600°C, 375°C to 600°C, 400°C to 600°C, 425°C to 600°C, 450°C to 600°C, 475°C to 600°C, 500°C to 600°C, 525°C to 600°C, 550°C to 600°C, 575°C to 600°C, 350°C to 575°C, 375°C to 575°C, 400°C to 575°C, 425°C to 575°C, 450°C to 575°C, 475 ℃ to 575℃, 500℃ to 575℃, 525℃ to 575℃, 550℃ to 575℃, 350℃ to 550℃, 375℃ to 550℃, 400℃ to 550℃, 425℃ to 550℃, 450℃ to 550℃, 475℃ to 550℃, 500℃ to 550℃, 525℃ to 550℃, 350℃ to 525℃, 375℃ to 525℃, 400℃ to 525℃, 425℃ to 525℃, 450℃ to 525℃, 475℃ to 525℃, 500℃ to 525℃, 350℃ to 500℃, 375℃ to 525℃ ℃ to 500℃, 400℃ to 500℃, 425℃ to 500℃, 450℃ to 500℃, 475℃ to 500℃, 350℃ to 475℃, 375℃ to 475℃, 400℃ to 475℃, 425℃ to 475℃, 450℃ to 475℃, 350℃ to 450℃, 375℃ to 450℃, 400℃ to 450℃, 425℃ to 450℃, 350℃ to 425℃, 375℃ to 425℃, 400℃ to 425℃, 350℃ to 400℃, 375℃ to 400℃, or 350℃ to 375℃.

[0032] In embodiments, calcination is carried out in air. In such embodiments, the calcination temperature may be from 200°C to 500°C, from 200°C to 500°C, from 400°C to 500°C, from 425°C to 500°C, from 450°C to 500°C, from 475°C to 500°C, from 350°C to 475°C, from 375°C to 475°C, from 400°C to 475°C, from 425°C to 475°C, from 450°C to 475°C, from 350°C to 450°C, from 375°C to 450°C, from 400°C to 450°C, from 425°C to 450°C, from 350°C to 425°C, from 375°C to 400°C, or from 350°C to 375°C.

[0033] In the already formed Mo v V w A y Bi z O x After the oxidative dehydrogenation catalyst, Mo v V w A y Bi z O x The oxidative dehydrogenation catalyst can be used in a process for converting alkanes in an alkane-containing feed stream into olefins. As the run time increases, the process disclosed and described herein can be further dehydrogenated by Mo v V w A y Bi z O x The oxidative dehydrogenation catalyst provides improved olefin selectivity. The process disclosed and described herein generally comprises reacting a feed stream comprising alkanes (paraffins) with a feed stream comprising Mo v V w A y Bi z O xThe material of oxidative dehydrogenation catalyst contacts in reaction zone, converts at least a portion of alkane into alkene, produces the product stream comprising paraffin and alkene.It should be understood that oxidative dehydrogenation catalyst can be used alone or can be used together with other additives.Reaction zone is not particularly limited, and in an embodiment, can use the reactor of any type that allows the circulation or continuous operation of the method.In an embodiment, reaction zone can be fixed bed reactor, fluidized bed reactor, moving bed reactor, bubbling bed reactor, circulating fluidized bed reactor, countercurrent reactor or ebullated bed reactor (each optionally with oxygen co-feed).Reaction zone is not particularly limited to single reaction zone, and can be made up of a plurality of reactors of series or parallel configuration.Finally, the paraffin in the product stream is separated from the alkene, paraffin can be recycled back in the feed stream, and alkene is used in downstream system or as the material in various products and methods.Hereinafter, the method according to the embodiment disclosed and described herein will be provided in more detail.

[0034] In one embodiment, the feed stream is fed into the reaction zone, and the feed stream comprises at least one alkane. In an embodiment, the feed stream can comprise alkanes (e.g., 100% alkanes) completely. In one or more embodiments, the feed stream can contain oxygen, steam, and / or an inert gas. In an embodiment, the feed stream comprises 30% by volume (vol%) to 90% by volume alkanes, 35% by volume to 90% by volume alkanes, 40% by volume to 90% by volume alkanes, 45% by volume to 90% by volume alkanes, 50% by volume to 90% by volume alkanes, 55% by volume to 90% by volume alkanes, 60% by volume to 90% by volume alkanes, 65% by volume to 90% by volume alkanes, 70% by volume to 90% by volume alkanes, 75% by volume to 90% by volume alkanes, 80% by volume to 90% by volume alkanes, 85% by volume to 90% by volume alkanes, 30% by volume to 85% by volume alkanes , 35vol% to 85vol% alkanes, 40vol% to 85vol% alkanes, 45vol% to 85vol% alkanes, 50vol% to 85vol% alkanes, 55vol% to 85vol% alkanes, 60vol% to 85vol% alkanes, 65vol% to 85vol% alkanes, 70vol% to 85vol% alkanes, 75vol% to 85vol% alkanes, 80vol% to 85vol% alkanes, 30vol% to 80vol% alkanes, 35vol% to 80vol% alkanes, 40vol% to 80vol% alkanes, 45vol% to 80vol% alkanes , 50vol% to 80vol% alkanes, 55vol% to 80vol% alkanes, 60vol% to 80vol% alkanes, 65vol% to 80vol% alkanes, 70vol% to 80vol% alkanes, 75vol% to 80vol% alkanes, 30vol% to 75vol% alkanes, 35vol% to 75vol% alkanes, 40vol% to 75vol% alkanes, 45vol% to 75vol% alkanes, 50vol% to 75vol% alkanes, 55vol% to 75vol% alkanes, 60vol% to 75vol% alkanes, 65vol% to 75vol% alkanes , 70vol% to 75vol% alkanes, 30vol% to 70vol% alkanes, 35vol% to 70vol% alkanes, 40vol% to 70vol% alkanes, 45vol% to 70vol% alkanes, 50vol% to 70vol% alkanes, 55vol% to 70vol% alkanes, 60vol% to 70vol% alkanes, 65vol% to 70vol% alkanes, 30vol% to 65vol% alkanes, 35vol% to 65vol% alkanes, 40vol% to 65vol% alkanes, 45vol% to 65vol% alkanes, 50vol% to 65vol% alkanes,55vol% to 65vol% alkanes, 60vol% to 65vol% alkanes, 30vol% to 60vol% alkanes, 35vol% to 60vol% alkanes, 40vol% to 60vol% alkanes, 45vol% to 60vol% alkanes, 50vol% to 60vol% alkanes, 55vol% to 60vol% alkanes, 30vol% to 55vol% alkanes, 35vol% to 55vol% alkanes, 40vol% to 55vol% alkanes, 45vol% to 5 5 vol% alkanes, 50 vol% to 55 vol% alkanes, 30 vol% to 50 vol% alkanes, 35 vol% to 50 vol% alkanes, 40 vol% to 50 vol% alkanes, 45 vol% to 50 vol% alkanes, 30 vol% to 45 vol% alkanes, 35 vol% to 45 vol% alkanes, 40 vol% to 45 vol% alkanes, 30 vol% to 40 vol% alkanes, 35 vol% to 40 vol% alkanes, or 30 vol% to 35 vol% alkanes.

[0035] In embodiments, the at least one alkane is selected from the group consisting of ethane, propane, and combinations thereof. In embodiments, the inert gas is selected from the group consisting of nitrogen, CO2, and combinations thereof.

[0036] According to one or more embodiments, the Mo in the reaction zone v V w A y Bi z O xThe weight ratio of the oxidative dehydrogenation catalyst to the alkane in the reaction zone is 250 to 10, 225 to 10, 200 to 10, 175 to 10, 150 to 10, 125 to 10, 100 to 10, 75 to 10, 50 to 10, 25 to 10, 250 to 25, 225 to 25, 200 to 25, 175 to 25, 150 to 25, 125 to 25, 100 to 25, 75 to 25, 50 to 25, 250 to 50, 225 to 50, 200 to 50, 175 to 50, 150 to 50, 125 to 50, 100 to 50, 75 to 50, 250 to 75, or 225 to 75, 200 to 75, 175 to 75, 150 to 75, 125 to 75, 100 to 75, 250 to 100, 225 to 100, 200 to 100, 175 to 100, 150 to 100, 125 to 100, 250 to 125, 225 to 125, 200 to 125, 175 to 125, 150 to 125, 250 to 150, 225 to 150, 200 to 150, 175 to 150, 250 to 175, 225 to 175, 200 to 175, 250 to 200, 225 to 200, or 250 to 225. In embodiments where the reaction zone is a fluidized bed catalyst or the like, the ratio of catalyst to alkane is controlled by the mass feed rate of alkane and the mass feed rate of catalyst to the reaction zone.

[0037] In embodiments, the feed stream is substantially free of oxygen, meaning that the feed stream comprises less than 2.0 volume percent (vol%) oxygen, less than 1.5 vol% oxygen, or less than 0.5 vol% oxygen.In one or more embodiments, the feed stream is free of oxygen.

[0038] In one or more embodiments, an oxygen stream is added to the reaction zone. The oxygen concentration in the oxygen stream is not particularly limited. For example, the oxygen concentration in the oxygen stream can be 0.1 vol% to 99.9 vol%, such as 5.0 vol% to 95.0 vol%, 10.0 vol% to 90.0 vol%, 15.0 vol% to 85.0 vol%, 20.0 vol% to 80.0 vol%, 25.0 vol% to 75.0 vol%, 30.0 vol% to 70.0 vol%, 35.0 vol% to 65.0 vol%, 40.0 vol% to 60.0 vol%, or 45.0 vol% to 55.0 vol%. In one or more embodiments, the oxygen concentration in the oxygen stream is relatively low, such as 0.1 vol% to 5.0 vol%, 0.2 vol% to 5.0 vol%, 0.5 vol% to 5.0 vol%, 0.8 vol% to 5.0 vol%, 1.0 vol% to 5.0 vol%, 1.2 vol% to 5.0 vol%, 1.5 vol% to 5.0 vol%, 1.8 vol% to 5.0 vol%, 2.0 vol% to 5.0 vol%, 2. vol%, 2.5 vol% to 5.0 vol%, 2.8 vol% to 5.0 vol%, 3.0 vol% to 5.0 vol%, 3.2 vol% to 5.0 vol%, 3.5 vol% to 5.0 vol%, 3.8 vol% to 5.0 vol%, 4.0 vol% to 5.0 vol%, 4.2 vol% to 5.0 vol%, 4.5 vol% to 5.0 vol%, or 4.8 vol% to 5.0 vol%. In embodiments, the oxygen stream can be air, which typically has an oxygen concentration of about 21.0 vol%.

[0039] In embodiments, the oxygen stream can be added to the reaction zone sequentially with the feed stream, such that the feed stream and the oxygen stream are not added to the reaction zone simultaneously. It should be understood that in embodiments, the oxygen stream can be added at different points during the reaction. This can be achieved by introducing the oxygen stream into the reaction zone at different locations within the reaction zone and / or introducing the oxygen stream at different time periods while the reaction is occurring.

[0040] In one or more embodiments, the oxygen stream is added to the reaction zone simultaneously with the feed stream. In such embodiments, the volume ratio of oxygen (in the oxygen stream) to alkane (in the feed stream) in the reaction zone is greater than 0.0 to 1.0, 0.1 to 1.0, 0.2 to 1.0, 0.3 to 1.0, 0.4 to 1.0, 0.5 to 1.0, 0.6 to 1.0, 0.7 to 1.0, 0.8 to 1.0, 0.9 to 1.0, or greater than 0.0 to 0.2, 0.0 to 0.3, 0.0 to 0.4, 0.0 to 0.5, 0.0 to 0.6, 0.0 to 0.7, 0.0 to 0.8, or 0.0 to 0.9.

[0041] The feed stream is reacted with Mo as disclosed and described herein in a reaction zone under reaction conditions sufficient to form a product stream comprising olefins. v V w A y Bi z O x The reaction conditions include the temperature in the reaction zone, which, according to one or more embodiments, ranges from 300°C to 700°C, 350°C to 700°C, 400°C to 700°C, 450°C to 700°C, 500°C to 700°C, 550°C to 700°C, 600°C to 700°C, 650°C to 700°C, 300°C to 650°C, 350°C to 650°C, 400°C to 650°C, 450°C to 650°C, 500°C to 650°C, 550°C to 650°C, 600°C to 600°C, 300°C to 600°C, 350°C to 650°C, 0°C to 600°C, 400°C to 600°C, 450°C to 600°C, 500°C to 600°C, 550°C to 600°C, 300°C to 550°C, 350°C to 550°C, 400°C to 550°C, 450°C to 550°C, 500°C to 550°C, 300°C to 500°C, 350°C to 500°C, 400°C to 500°C, 450°C to 500°C, 300°C to 450°C, 350°C to 450°C, 400°C to 450°C, 300°C to 400°C, 350°C to 400°C, or 300°C to 350°C.

[0042] In embodiments, the reaction conditions further comprise a pressure inside the reaction zone of 0 barg (0 KPa) to 20 barg (2000 KPa), 5 barg (500 KPa) to 20 barg (2000 KPa), 10 barg (1000 KPa) to 20 barg (2000 KPa), 15 barg (1500 KPa) to 20 barg (2000 KPa), 0 barg (0 KPa) to 15 barg (1500 KPa), 5 barg (500 KPa) to 15 barg (1500 KPa), 10 barg (1000 KPa) to 15 barg (1500 KPa), 0 barg (0 KPa) to 10 barg (1000 KPa), 5 barg (500 KPa) to 10 barg (1000 KPa), or 0 barg (0 KPa) to 5 barg (500 KPa).

[0043] According to embodiments, the weight hourly space velocity (WHSV) of the alkane feed stream and, optionally, the oxygen stream in the reaction zone is from 0.1 hour ( / h) to 10.0 / h, 0.5 / h to 10.0 / h, 1.0 / h to 10.0 / h, 2.0 / h to 10.0 / h, 3.0 / h to 10.0 / h, 4.0 / h to 10.0 / h, 5.0 / h to 10.0 / h, 6.0 / h to 10.0 / h, 7.0 / h to 10.0 / h, 8.0 / h to 10.0 / h, 9.0 / h to 10.0 / h, 0.1 / h to 9.0 / h, 0.5 / h to 9.0 / h, 1.0 / h to 9.0 / h, 2.0 / h to 9.0 / h, 3.0 / h to 9.0 / h, 4.0 / h to 9.0 / h, 5.0 / h to 9.0 / h, 6.0 / h to 9.0 / h, 7.0 / h to 9.0 / h, 8.0 / h to 9.0 / h, 0.1 / h to 8.0 / h, 0.5 / h to 8.0 / h, 1.0 / h to 8.0 / h, 2.0 / h to 8.0 / h, 3.0 / h to 8.0 / h, 4.0 / h to 8.0 / h, 5.0 / h to 8.0 / h, 6.0 / h to 8.0 / h, 7.0 / h to 8.0 / h, 0.1 / h to 7.0 / h, 0.5 / h to 7.0 / h, 1.0 / h to 7.0 / h, 2.0 / h to 7.0 / h, 3.0 / h to 7.0 / h, 4.0 / h to 7.0 / h, 5.0 / h to 7.0 / h, 6.0 / h to 7.0 / h, 0.1 / h to 6.0 / h, 0.5 / h to 6.0 / h, 1.0 / h to 6.0 / h, 2.0 / h to 6.0 / h, 3.0 / h to 6.0 / h, 4.0 / h to 6.0 / h, 5.0 / h to 6.0 / h, 0.1 / h to 5.0 / h, 0.5 / h to 5.0 / h, 1.0 / h to 5.0 / h, 2.0 / h to 5.0 / h, 3.0 / h to 5.0 / h, 4.0 / h to 5.0 / h, 0.1 / h to 4.0 / h, 0.5 / h to 4.0 / h, 1.0 / h to 4.0 / h, 2.0 / h to 4.0 / h, 3.0 / h to 4.0 / h, 0.1 / h to 3.0 / h, 0.5 / h to 3.0 / h, 1.0 / h to 3.0 / h, 2.0 / h to 3.0 / h, 0.1 / h to 2.0 / h, 0.5 / h to 2.0 / h, 1.0 / h to 2.0 / h, 0.1 / h to 1.0 / h, 0.5 / h to 1.0 / h, or 0.1 / h to 0.5 / h.

[0044] Example

[0045] Example 1

[0046] A mixture of 34 mL of H2O and 160 μL of ethylene glycol was added to a 45 mL Teflon insert autoclave (Universal Acid Digestion Vessel Model 4744, Parr). While stirring the mixture, 2.7126 g of MoO3, 0.5141 g of V2O5, 0.4373 g of Bi2O3, 0.4391 g of WO3, 0.5141 g of citric acid, and 0.2388 g of oxalic acid were added in sequence and stirred for 10 minutes. 0.3 W 0.1 Bi 0.1 O x The hydrothermal synthesis of was carried out in a rotary oven at 190°C for 48 hours while rotating at 10 rpm. The material obtained from the hydrothermal synthesis was purified using vacuum filtration with 200 mL of deionized water. The sample was subsequently dried at 85°C overnight.

[0047] After drying, the material was calcined at 450°C under N2 flow (at a heating rate of 2°C / min) for 2 hours. The material was compacted under 7 tons of pressure, crushed and sieved to 40-80 mesh, and then loaded into the reactor. The reaction conditions will be discussed in detail below.

[0048] Example 2

[0049] A mixture of 34 mL of H2O and 160 microliters of ethylene glycol was added to a 45 mL Teflon insert autoclave (Universal Acid Digestion Vessel Model 4744, Parr). While stirring the mixture, 2.7126 g of MoO3, 0.5141 g of V2O5, 0.4373 g of Bi2O3, 0.5446 g of Bi2(WO4)3, 0.5422 g of citric acid, and 0.2388 g of oxalic acid were added in sequence and stirred for 10 minutes. 0.3 W 0.75 Bi 0.15 O x The hydrothermal synthesis of was carried out in a rotary oven at 190°C for 48 hours while rotating at 10 rpm. The material obtained from the hydrothermal synthesis was purified using vacuum filtration with 200 mL of deionized water. The material was then dried at 85°C overnight.

[0050] After drying, the material was calcined at 450°C under N2 flow (at a heating rate of 2°C / min) for 2 hours. The material was compacted under 7 tons of pressure, crushed and sieved to 40-80 mesh, and then loaded into the reactor. The reaction conditions will be discussed in detail below.

[0051] Example 3

[0052] A mixture of 34 mL of H2O and 157 μL of ethylene glycol was added to a 45 mL Teflon insert autoclave (Universal Acid Digestion Vessel Model 4744, Parr). While stirring the mixture, 2.7126 g of MoO3, 0.5141 g of V2O5, 0.4373 g of Bi2O3, 0.3643 g of Ta2O5, 0.5413 g of citric acid, and 0.2388 g of oxalic acid were added in sequence and stirred for 10 minutes. 0.3 Ta 0.087 Bi 0.1 O x The hydrothermal synthesis of was carried out in a rotary oven at 200°C for 48 hours while rotating at 10 rpm. The material obtained from the hydrothermal synthesis was purified using vacuum filtration with 200 mL of deionized water. The sample was then dried at 85°C overnight.

[0053] After drying, the material was calcined at 450°C under N2 flow (at a heating rate of 5°C / min) for 2 hours. The material was compacted under 7 tons of pressure, crushed and sieved to 40-80 mesh, and then loaded into the reactor. The reaction conditions will be discussed in detail below.

[0054] Comparative Example 1

[0055] In a glass beaker, 1.33g (NH4)6Mo7O 24 ·4H2O was dissolved in 15 mL of H2O, while in a separate beaker, 2.118 g of VOSO4·xH2O was dissolved in 90 mL of H2O by magnetic stirring at room temperature. The contents of the two beakers were then combined in a 120 mL-Teflon insert autoclave (Universal Acid Digestion Vessel Model 4748, Parr). While stirring, 0.080 g of (NH4)6H2W 12 O 40 6H2O, 0.052g Cu(NH4)2Cl4·2H2O and 0.109g Sb2O3 were added to the mixture in this order and stirred for 10 minutes. The pH value was constant at pH=2.4 before and after the addition of W, Sb and Cu compounds. 0.25 W 0.1 Sb 0.05 Cu 0.1 The hydrothermal synthesis of Ox was carried out in a static preheated oven at 185° C. for 20 hours. The material obtained from the hydrothermal synthesis was purified using vacuum filtration with 90 mL of deionized water and then dried at 85° C. overnight.

[0056] Reactor testing

[0057] The performance tests were carried out in a fixed-bed reactor setup with an SS316 reactor tube (I.D. 3 mm) from SINTEF (high-pressure reactor assembly module). For the catalytic tests, 250 mg of 40-mesh - 80-mesh catalyst particles were loaded in the reactor, and the reactor was operated in a cyclic mode at the desired temperature in which the ethane exposure period was alternated with inert gas purge and oxidative regeneration:

[0058] At a pressure of 2.5 bar (absolute) and a WHSV of 1.6 / hr, the lattice oxidative dehydrogenation (LODh) step with a 6-minute ethane feed pulse used a 50 vol.% ethane / helium flow rate of 15 mL / min.

[0059] At a pressure of 2.5 bar (absolute), the 75-minute regeneration step used a 2.5 vol.% O2 / helium flow rate of 10 mL / min.

[0060] The reactor effluent composition was obtained by gas chromatography (GC), and the conversion and carbon-based selectivity were calculated using the following equations:

[0061] XC2H6 (%) = [(ηC2H6,in – ηC2H6,out) / ηC2H6,in]·100; and (1)

[0062] S j (%) = [αj·ηj,out / ∑αj·ηj,out]·100 (2)

[0063] where XC2H6 is defined as the C2H6 conversion (%), η,in is defined as the molar inlet flow rate of the component (mol / min), η,out is the molar outlet flow rate of the component (mol / min), S j is defined as the carbon-based selectivity (%) of product j, and αj is the number of carbon atoms in product j. The carbon balance for all experiments was in the range of 99 - 102%. <000034​​​​​​​​​​​​​​

[0068] <![CDATA[XC2H6(%)]]> <![CDATA[SC2H4(%)]]> SCO (%) <![CDATA[SCO2(%)]]> <![CDATA[SCH4(%)]]> Catalyst / Ethane Example 1 41.6 83.3 9.6 7.1 0.05 452 35.9 83.1 9.5 7.4 0.07 218 27.8 82.00 9.8 8.1 0.09 144 18.7 79.7 10.8 9.4 0.13 85 12.3 76.2 11.5 12.1 0.17 61 9.7 76.6 11.8 11.5 0.16 47 Example 2 44.0 85.0 8.5 6.5 0.03 385 36.8 84.7 8.3 7.0 0.03 197 35.3 84.3 8.4 7.2 0.05 132 27.7 84.0 8.6 7.4 0.05 99.5 20.7 83.0 9.0 8.0 0.06 80 12.5 79.3 10.5 10.1 0.08 57 8.0 80.6 10.2 9.0 0.08 45 Example 3 33.2 82.2 9.9 7.8 0.02 460 24.7 83.0 9.3 7.7 0.03 207 18.4 82.0 9.9 8.1 0.04 115 11.9 80.0 11.0 9.0 0.05 75 8.7 78.8 11.7 9.4 0.08 53 Comparative Example 1 30.33 62.39 24.22 13.37 0.02 278 19.90 67.32 20.88 11.77 0.02 167 17.03 67.92 20.67 11.40 0.01 120 14.57 69.27 19.74 10.99 0.00 93 13.15 70.17 19.16 10.67 0.00 76 14.58 73.24 16.62 10.14 0.00 56 11.31 73.40 17.03 9.58 0.00 44

[0069] As can be observed from Table 2, Examples 1 to 3 exhibit high activity for ethane conversion with high selectivity for ethylene (>75%). This highlights the excellent performance of these newly discovered W / Ta, Bi-containing materials crystallized in the Pba2-32 crystal structure.

[0070] In contrast, Comparative Example 1 exhibited lower activity and lower selectivity, which highlights the importance of both W and Bi in the structure.

[0071] Example 2 was also tested in an oxidative dehydrogenation process with O2 co-feed at a constant pressure of 8 bar and 315°C, and the feed composition was varied with different amounts of ethane, oxygen, water (steam) and inert gases (helium and nitrogen).

[0072] Catalytic screening was performed in a dedicated module of a high throughput (HT) parallel fixed bed reactor (PFBR) comprising 16 quartz reactor tubes enclosed in a stainless steel bell jar that could be pressurized with N2 to the same pressure as the process pressure. This allowed the use of quartz reactors and minimized the number of seals exposed to high pressure differentials. Of the sixteen microreactors, two were used as blanks, i.e. loaded with quartz chips to monitor the feed composition throughout the experiment. The other reactors were loaded as follows (from bottom to top): Q-felt, quartz chip layer, catalyst bed, quartz chip layer and Q-felt on top, with the aim of preparing approximately the same (total) volume each time. The test was started with a nitrogen purge while the temperature and pressure were raised to the desired process values ​​before feeding various compositions of ethane, oxygen, steam (water) and inert gases (helium, nitrogen) at a total flow rate of approximately 14 sccm per reactor tube.

[0073] Table 3: Catalytic performance conditions

[0074]

[0075] The catalytic performance data shown in Table 4 below are averages calculated from three or more independent GC analyses collected approximately every 3.5 hours over a fixed process period lasting a minimum of 12 hours.

[0076] Table 4: Catalytic performance data under different conditions

[0077]

[0078] Table 4 above shows that the novel W- and Bi-containing compositions are also capable of selectively converting ethane to ethylene with a selectivity of >75% in the ethane:O2 ratio range of 2-6.

[0079] It will be apparent to those skilled in the art that various modifications and variations may be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Therefore, this specification is intended to cover modifications and variations of the various embodiments described herein, provided that such modifications and variations fall within the scope of the appended claims and their equivalents.

Claims

1. An oxidative dehydrogenation catalyst, comprising: (i) has the formula Mo v V w A y Bi z O x A structure comprising a mixed oxide of molybdenum (Mo), vanadium (V), tungsten (W) or tantalum (Ta) and bismuth (Bi), wherein v is 1, w is 0.2 to 0.5, A is W or Ta, y is 0.001 to 0.3, z is 0.01 to 0.3, and x is the oxygen content required to make the structure charge balanced, and (ii) a crystal structure containing a Pba2-32 space group, which was obtained by using Cu-K α The reflections measured by X-ray diffraction (XRD) were characterized as follows: 。 2. The oxidative dehydrogenation catalyst according to claim 1, wherein the oxidative dehydrogenation catalyst is composed of a catalyst having the formula Mo v V w A y Bi z O x The structure comprises an oxide of molybdenum (Mo), vanadium (V), tungsten (W) or tantalum (Ta) and bismuth (Bi), wherein v is 1, w is 0.2 to 0.5, A is W or Ta, y is 0.001 to 0.3, z is 0.01 to 0.3, and x is the oxygen content required to make the structure charge balanced.

3. The oxidative dehydrogenation catalyst according to claim 1, wherein the oxidative dehydrogenation catalyst is substantially free of tellurium (Te).

4. The oxidative dehydrogenation catalyst according to any one of claims 1 to 3, wherein the oxidative dehydrogenation catalyst has the following formula: MoV 0.2-0.3 W 0.05-0.15 Bi 0.1-0.15 O x .

5. The oxidative dehydrogenation catalyst according to any one of claims 1 to 3, wherein the oxidative dehydrogenation catalyst has the following formula: MoV 0.2-0.5 Ta 0.05-0.18 Bi 0.1-0.15 O x .

6. A method for forming an oxidative dehydrogenation catalyst, the method comprising: adding a molybdenum-containing compound, a vanadium-containing compound, a bismuth-containing compound, and a tungsten-containing compound or a tantalum-containing compound and one or more organic acids to a mixture of an alkylene glycol or an alcoholamine and water to form a starting mixture; treating the starting mixture by hydrothermal synthesis at a hydrothermal synthesis temperature of 150° C. to 250° C.; and Separation of Mo from the retained liquid v V w A y Bi z O x , where A is W or Ta, The starting mixture comprises at least one of molybdenum trioxide (MoO3) and vanadium pentoxide (V2O5).

7. The method for forming an oxidative dehydrogenation catalyst according to claim 6, wherein the one or more organic acids include at least one of citric acid (C6H8O7), oxalic acid (C2H2O4), and mixtures thereof.

8. The method for forming an oxidative dehydrogenation catalyst according to claim 6 or claim 7, wherein the tungsten-containing compound is selected from the group consisting of tungsten trioxide (WO3), bismuth tungstate (Bi2(WO4)3) and ammonium metatungstate hydrate ((NH4)6H2W 12 O 40 ) and mixtures thereof.

9. The method for forming an oxidative dehydrogenation catalyst according to any one of claims 6 to 8, wherein the bismuth-containing compound is selected from the group consisting of bismuth oxide (Bi2O3), bismuth sulfate (Bi2(SO4)3), bismuth citrate (BiC6H5O7) and bismuth nitrate (Bi(NO3)3).

10. The method for forming an oxidative dehydrogenation catalyst according to any one of claims 6 to 9, wherein the alkylene glycol is ethylene glycol (C2H6O2).

11. The method for forming an oxidative dehydrogenation catalyst according to any one of claims 5 to 10, wherein the starting mixture comprises MoO3 and V2O5.

12. A method for converting paraffins to olefins, the method comprising: contacting a feed stream comprising paraffins with a material comprising an oxidative dehydrogenation catalyst according to any one of claims 1 to 4; converting at least a portion of the paraffins to olefins, thereby producing a product stream comprising paraffins and olefins; as well as The olefins are separated from the paraffins in the product stream.

13. The process of claim 12, wherein the process further comprises contacting a second stream comprising oxygen with the feed stream comprising paraffins and the oxidative dehydrogenation catalyst.

14. The process of claim 13, wherein the conversion occurs at a temperature of 300 to 700°C and a pressure of 0 to 20 barg.

15. The process of any one of claims 13 and 14, wherein the conversion occurs at an alkane weight hourly space velocity (WHSV) of 0.1 / hr to 10 / hr.

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