Alkane dehydrogenation catalyst

Abstract

A process is described for preparing an alkane dehydrogenation catalyst comprising from 10 wt% to 40 wt% of chromium oxide (III) (Cr2O3), from 0.1 wt% to 5 wt% of an alkali metal oxide, and from 60 wt% to 90 wt% of aluminum oxide (Al2O3). A method can include mixing a solid aluminum hydroxide source with a water-insoluble chromium (III) oxide source, an alkali metal oxide source, and an aqueous non-metallic acid to produce a catalyst precursor. The catalyst precursor can be dried and calcined at 700-1000 DEG C to produce the catalyst of the invention.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to and the benefit of European Patent Application No. 202241074442, filed on December 22, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention generally relates to a method for preparing an alkane dehydrogenation catalyst using a water-insoluble source of chromium (III) oxide, solid aluminum hydroxide, and an alkali metal oxide source. Background Art

[0004] Alkane dehydrogenation is a well-established process for producing a variety of useful hydrocarbon products, such as isobutylene for conversion to MTBE, isooctane, and alkylate for gasoline replenishment and enrichment. Several catalytic processes are currently available for the catalytic dehydrogenation of light alkanes, including Süd-Chemie Methods, UOP Method, Phillips' Star TM The catalysts used in these methods are made from two different groups of materials. The Snamprogetti-Yarsintee process and the UOP-Phillips process use chromium oxide-alumina catalysts. In contrast, the catalysts used in the UOP and Phillips processes contain precious metals on supported catalysts. Chromium oxide-alumina dehydrogenation catalyst technology has been used for decades. For the dehydrogenation catalysts used in the above-mentioned processes, the stability of the catalyst plays an important role in the overall efficiency of the dehydrogenation process. Due to the extreme temperature ranges in which the catalytic dehydrogenation procedures are carried out, the life expectancy of the catalyst is generally limited. Therefore, improvements in catalyst stability translate into longer catalyst life or improved catalyst selectivity during the catalyst life, which allows better catalyst utilization, which ultimately reduces catalyst consumption during the dehydrogenation process.

[0005] There are many different types of alumina that can be used as a support for dehydrogenation catalysts. However, medium to high surface area gamma alumina has been the preferred choice as a support for such catalysts. Chromium (III) oxide supported on eta alumina can be highly stable compared to chromium oxide supported on gamma alumina.

[0006] Current chromium oxide-aluminum oxide dehydrogenation catalysts are produced by impregnating an aluminum support with a highly concentrated chromic acid solution, which primarily contains hexavalent chromium (chromium (VI)), which is toxic and carcinogenic and therefore highly undesirable for use on an industrial scale. One approach to overcoming the use of hexavalent chromium in catalyst preparation involves impregnating the aluminum support with an aqueous solution of a water-soluble chromium (III) salt, such as chromium nitrate. This approach requires multiple impregnation steps to achieve the desired chromium oxide content. Each impregnation step would require intermediate drying and calcination, so such a multiple impregnation process would be time- and labor-intensive, and cost-prohibitive relative to conventional preparation procedures involving chromium (VI)-containing materials.

[0007] Attempts to overcome the use of hexavalent chromium have been described. For example, a Cr2O3 / alumina support can be impregnated with additional chromium nitrate and potassium nitrate, or alternatively, the support can be impregnated with an aqueous solution containing chromium nitrate, sodium hydroxide, magnesium nitrate, and zirconium carbonate. A disadvantage of these methods is that catalyst preparation involves an impregnation process followed by drying and calcination steps. In addition to increasing costs, such methods are also time- and labor-intensive.

[0008] Another attempt to produce a chromium-based dehydrogenation catalyst involves extruding chromium(III) oxide powder, activated alumina powder, and an acidic solution of calcium nitrate and potassium nitrate, followed by drying and calcining. The dried extrudates are then baked in nitrogen to obtain the catalyst. Catalysts formed in this way are expected to exhibit alumina in the form of gamma alumina, which strongly affects catalyst stability.

[0009] While many methods exist for producing chromium-based dehydrogenation catalysts, they can be inefficient and expensive and / or produce catalysts with low conversion / activity and / or limited stability. Summary of the Invention

[0010] It has been discovered that a solution to at least one problem associated with methods of producing alkane dehydrogenation catalysts is provided. In one aspect, the present invention can include a method of incorporating chromium (III) oxide, at least one alkali metal oxide, optionally an alkaline earth metal oxide, optionally lanthanum oxide, and aluminum hydroxide into a formed structure (e.g., an extrudate or tablet). The method eliminates the need for chromium (VI)-containing compounds and multi-step impregnation and / or heating procedures. Thus, the present invention provides a simple, cost-effective method for making a chromium oxide-alumina dehydrogenation catalyst having improved stability for the dehydrogenation of lower paraffins. Notably, the method does not require impregnation with an additional water-soluble chromium compound after the extrudate is formed and calcined to obtain the desired amount of chromium (III) oxide in the catalyst.

[0011] In one aspect of the present invention, a method for producing an alkane dehydrogenation catalyst is described. One method can include extruding and / or tableting a mixture comprising solid aluminum hydroxide, a water-insoluble chromium (III) oxide source, an alkali metal oxide source, and an aqueous non-metallic acid to produce a catalyst precursor. In some aspects, the mixture can be aged at a temperature of 20° C. to 40° C. for 0.5 to 24 hours prior to extrusion and / or tableting. The catalyst precursor can be dried and thereafter calcined at a temperature of 700° C. to 1000° C. to produce an alkane dehydrogenation catalyst comprising 10 wt % to 40 wt % chromium (III) oxide (Cr2O3), 0.1 wt % to 5 wt % alkali metal oxide, and 60 wt % to 90 wt % aluminum oxide (Al2O3). In some aspects, the calcination can be carried out under air. Non-limiting examples of solid aluminum hydroxide can include crystalline aluminum trihydroxide (e.g., bayerite, neoalumina, or mixtures thereof), crystalline aluminum oxide-hydroxides (boehmite), gelatinous aluminum hydroxide (e.g., amorphous aluminum hydroxide, pseudobohemite, or mixtures thereof), or mixtures thereof. The solid aluminum hydroxide can contain 90 wt%-100 wt% of crystalline aluminum trihydroxide. In another aspect, the solid aluminum hydroxide can contain 0 wt%-10 wt% of crystalline aluminum oxide-hydroxide or gelatinous aluminum hydroxide, or a combination thereof, with the remainder being crystalline aluminum trihydroxide. The alkali metal oxide source can include a sodium oxide source, a lithium oxide source, a cesium oxide source, a potassium oxide source, or mixtures thereof, preferably sodium oxide. In some aspects, the mixture can include a lanthanide oxide source. Non-limiting examples of lanthanide oxide sources can include lanthanum oxide sources, cerium oxide sources, or mixtures thereof. In some aspects, the mixture can include an alkaline earth metal oxide source. Non-limiting examples of alkaline earth metal oxide sources can include barium oxide (BaO) sources and / or strontium oxide (SrO) sources, and the catalyst comprises BaO, SrO, or a combination thereof. In another aspect, the mixture can further comprise a silica source. In such aspects, the catalyst can comprise 0.1 wt% to 5 wt% silica.

[0012] The catalyst may comprise 10 wt% to 40 wt% chromium (III) oxide (Cr2O3), 0.1 wt% to 5 wt% alkali metal oxide, and 60 wt% to 90 wt% aluminum oxide (Al2O3). For example, the catalyst may comprise 10 wt% to 40 wt% chromium (III) oxide (Cr2O3), 0.1 wt% to 5 wt% Na2O, and 60 wt% to 90 wt% aluminum oxide (Al2O3). As another example, the catalyst may comprise 10 wt% to 40 wt% chromium (III) oxide (Cr2O3), 0.1 wt% to 5 wt% Na2O, 0.1 wt% to 5 wt% Li2O, and 60 wt% to 90 wt% aluminum oxide (Al2O3). The catalyst may comprise 10 wt% to 40 wt% chromium (III) oxide (Cr2O3), 0.1 wt% to 5 wt% alkali metal oxides, 0.1 to 20 wt% alkaline earth metal oxides, and 60 wt% to 90 wt% aluminum oxide Al2O3. For example, the catalyst may comprise 10 wt% to 40 wt% chromium (III) oxide (Cr2O3), 0.1 wt% to 5 wt% Li2O, 0.1 to 20 wt% BaO, and 60 wt% to 90 wt% aluminum oxide Al2O3. In some aspects, the catalyst may comprise 60 wt% to 90 wt% Al2O3, 10 wt% to 40 wt% Cr2O3, 0.1 wt% to 5 wt% Na2O, 0.1 wt% to 20 wt% alkaline earth metal oxides, and 0.01 wt% to 3 wt% Li2O. For example, the catalyst may comprise 60 wt% to 90 wt% Al2O3, 10 wt% to 40 wt% Cr2O3, 0.01 wt% to 5 wt% Na2O, 0.1 wt% to 20 wt% BaO, and 0.1 wt% to 5 wt% Li2O. In some aspects, the catalyst may comprise 60 wt% to 90 wt% Al2O3, 10 wt% to 40 wt% Cr2O3, 0.1 wt% to 5 wt% Na2O, and 0.1 wt% to 5 wt% SiO2. In other aspects, the catalyst may comprise 60 wt% to 95 wt% Al2O3, 5 wt% to 40 wt% Cr2O3, 0.1 wt% to 5 wt% Na2O, and 0.1 wt% to 20 wt% lanthanide oxide, preferably 0.1 wt% to 5 wt% lanthanide oxide. For example, the catalyst may contain 60 wt% to 95 wt% Al2O3, 5 wt% to 40 wt% Cr2O3, 0.1 wt% to 5 wt% Na2O, and 0.1 wt% to 20 wt% La2O3.In one aspect, the catalyst may comprise 60 wt% to 95 wt% Al2O3, 5 wt% to 40 wt% Cr2O3, 0.1 wt% to 5 wt% Na2O, and 0.1 wt% to 20 wt% lanthanide oxide, preferably 0.1 wt% to 5 wt% lanthanide oxide, and 0.1 wt% to 20 wt% alkaline earth oxide. For example, the catalyst may comprise 60 wt% to 95 wt% Al2O3, 5 wt% to 40 wt% Cr2O3, 0.1 wt% to 5 wt% Na2O, and 0.1 wt% to 20 wt% La2O3, preferably 0.1 wt% to 5 wt% La2O3, and 0.1 wt% to 20 wt% BaO, preferably 0.1 wt% to 5 wt%, more preferably 0.1 wt% to 3 wt% BaO.

[0013] In another aspect of the present invention, a method for dehydrogenating alkanes is described. One method may include contacting a catalyst made by any of the methods of the present invention with an alkane to produce a dehydrogenated paraffin (olefin, preferably isobutene from isobutane).

[0014] Included below are definitions of various terms and phrases used throughout this specification.

[0015] The term "about" or "approximately" is defined as close to, as understood by those skilled in the art. In one non-limiting embodiment, the term is defined as being within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

[0016] The terms "wt%," "vol%," or "mol%" refer to the weight percent, volume percent, or mole percent, respectively, of a component, based on the total weight, volume, or moles of the material in which the component is included. In a non-limiting example, 10 g of a component in 100 g of a material is 10 wt% of the component.

[0017] The term "substantially" and variations thereof are defined to include ranges within 10%, within 5%, within 1%, or within 0.5%.

[0018] When used in the claims and / or specification, the terms "inhibit" or "reduce" or "prevent" or "avoid" or any variation of these terms includes any measurable reduction or complete inhibition to achieve the desired result.

[0019] As used in the specification and / or claims, the term "effective" means sufficient to achieve a desired, expected, or intended result.

[0020] The terms "mixtures thereof" and "combinations thereof," or any variations of these terms, when used in connection with a list of components in the claims and / or the specification, refer to any combination of two or more of the listed components, including such combinations in which one or more other listed components are not present.

[0021] When used in conjunction with the terms "comprising," "including," "containing," or "having" in the claims or the specification, the word "a" or "an" can mean "one", but it is also consistent with the meaning of "one or more", "at least one", and "one or more than one".

[0022] The words "comprise" (and any form of comprising), "have" (and any form of having), "include" (and any form of including), or "contains" (and any form of containing) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

[0023] The processes of the present invention may "comprise," "consist essentially of," or "consist of" specific ingredients, components, compositions, etc. disclosed throughout the specification. With respect to the transition phrase "consisting essentially of" in one non-limiting aspect, a fundamental and novel feature of the processes of the present invention is their ability to produce chromium / aluminum dehydrogenation catalysts in a cost-effective and energy-efficient manner.

[0024] Other objects, features and advantages of the present invention will become clear from the following drawings, specific embodiments and examples. However, it should be understood that the drawings, specific embodiments and examples, although representing specific embodiments of the present invention, are given by way of illustration only and are not intended to be limiting. In addition, it is contemplated that changes and adjustments within the spirit and scope of the present invention will become clear to those skilled in the art based on the specific embodiments. In other embodiments, features from a particular embodiment may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any other embodiment. In other embodiments, additional features may be added to the specific embodiments described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] For a more complete understanding, reference is now made to the following description taken in conjunction with the accompanying drawings, wherein:

[0026] Figure 1 A system for dehydrogenating alkanes according to an embodiment of the present invention is shown.

[0027] Figure 2 The powder X-ray diffraction pattern of the catalyst of the present invention is described.

[0028] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings. The drawings may not be drawn to scale. DETAILED DESCRIPTION

[0029] It has been discovered that a solution to at least one problem associated with making alkane dehydrogenation catalysts is provided. In one aspect of the present invention, a method for producing an alkane dehydrogenation catalyst can include mixing solid aluminum hydroxide and a water-insoluble chromium (III) oxide source with an alkali metal oxide source, optionally a silica source, optionally a lanthanide oxide source, optionally an alkaline earth metal source, an aqueous non-metallic acid, and water at room temperature (e.g., 20° C. to 70° C.) to form a formable mixture. The formable mixture can be formed (e.g., extruded and / or tableted) into extrudates or tablets of a catalyst precursor. The formable mixture can be aged at 20° C. to 40° C. for 0.5 to 24 hours. The catalyst precursor can be dried and calcined to produce the alkane dehydrogenation catalyst of the present invention. One advantage of this method is that it provides a simple, cost-effective method for making a chromium oxide-alumina dehydrogenation catalyst by using a water-insoluble chromium (III) oxide source instead of a chromium (VI)-containing material in combination with an alkali metal oxide source. The catalyst of the present invention has improved stability for the dehydrogenation of lower paraffins. While not wishing to be bound by any theory, it is believed that the presence of certain alkali metal oxides and / or alkaline earth metal oxides inhibits phase changes within the alumina, providing a strong and thermally stable catalyst.

[0030] A. Methods of making paraffin dehydrogenation catalysts.

[0031] Solid aluminum hydroxide and chromium (III) oxide source can be mixed at room temperature (e.g., 20° C.-40° C., preferably 25° C.) under high-speed stirring to form a uniform aluminum hydroxide / chromium (III) oxide source mixture. Water, aqueous non-metallic acid (e.g., inorganic acid, such as nitric acid), alkali metal oxide source, optionally silica source, optionally lanthanide oxide source, and optionally alkaline earth metal oxide source can be added to the aluminum hydroxide / chromium (III) oxide source mixture to form a formable mixture. Water, acid, alkali metal oxide source, optional silica source, optional lanthanide oxide source, and optional alkaline earth metal oxide source can be premixed and then added to the aluminum hydroxide / chromium (III) oxide source mixture, or these ingredients can be added in any order. In some embodiments, water, inorganic acid, alkali metal oxide source, optional silica source, optional lanthanide oxide source, and optional alkaline earth metal oxide source can be premixed, and the aluminum hydroxide / chromium (III) oxide source mixture can be added to the aqueous mixture. The formable mixture can be mixed at a high speed at a temperature (e.g., 20° C. to 60° C., preferably 25° C.) so that the formable mixture is suitable for forming. The formable mixture can be aged at room temperature (e.g., 20° C. to 40° C., preferably 25° C.) for 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 22, 24 hours or any range or value therebetween, preferably 0.5-2 hours. The formable mixture can be extruded and / or formed into any suitable shape, including a cylinder, a cube, a star, a trilobal, a quadrilobal, a granule, a pellet, or a sphere, by suitable mechanical means. The shaped catalyst precursor can be heated at a temperature of 50°C to 200°C, 100°C to 140°C, 110°C to 120°C, or 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, or any range or value therebetween to remove water. After drying, the shaped catalyst precursor can be calcined by heating the shaped catalyst precursor to a temperature of 700° C. to 1000° C., 800° C. to 900° C., or 700° C., 725° C., 750° C., 775° C., 800° C., 825° C., 850° C., 875° C., 900° C., 925° C., 950° C., 975° C., 1000° C., or any range or value therebetween, to produce the catalyst of the present invention. Calcination can be carried out in an inert or air atmosphere, preferably an air atmosphere. Calcination can convert any non-oxide metal source into an oxide.For example, a water-insoluble source of chromium (III) oxide can be converted to chromium oxide, a source of alkali metal oxide can be converted to an alkali metal oxide (e.g., lithium oxide, sodium oxide, or a mixture thereof), a source of lanthanide oxide can be converted to a lanthanide oxide (e.g., cerium oxide, lanthanum oxide, or a mixture thereof), and a source of alkaline earth metal oxide can be converted to an alkaline earth metal oxide (e.g., barium oxide, strontium oxide, or a mixture thereof).

[0032] The formable mixture may include other conventional materials, such as binders, cements, pore formers, texturizing agents, extrusion aids, lubricants, surfactants, and any other materials that aid in mixing or shaping or provide the desired structure to the as-received material after calcination. For example, in certain embodiments, the formable mixture includes a pore-forming organic compound, such as a polymer. The pore-forming organic compound does not dissolve into the water of the formable mixture and therefore remains as discrete small areas of organic matter within the material when formed. During calcination, the pore-forming organic compound is burned off, which forms gases that increase the porosity of the as-received material after calcination. The pore-forming organic polymer can be, for example, a polyolefin such as polyethylene, or a cellulose derivative such as methylcellulose. The pore-forming organic compound can be provided in the formable mixture in any desired amount, for example, in an amount of about 0.1 wt% to about 5 wt% on a dry basis. In certain embodiments, the pore-forming organic compound is present in the formable mixture in an amount of about 0.2 wt % to about 5 wt %, or about 0.5 wt % to about 5 wt %, or about 0.1 wt % to about 3 wt %, or about 0.2 wt % to about 3 wt %, or about 0.5 wt % to about 3 wt %, or about 0.1 wt % to about 2 wt %, or about 0.2 wt % to about 2 wt %, or about 0.5 wt % to about 2 wt %.

[0033] The formable mixture may comprise an aqueous non-metallic acid. A non-metallic acid is herein referred to as an acid whose molecular structure does not contain metal atoms. In certain embodiments of the present invention, the non-metallic acid is nitric acid. In other embodiments of the present invention, the non-metallic acid is an organic acid, such as formic acid or acetic acid. In still other embodiments of the present invention, the non-metallic acid is a combination of nitric acid and an organic acid, such as formic acid or acetic acid. The use of an organic acid can be beneficial because it can reduce the concentration of nitrogen oxides during heat treatment; however, it can also result in a less efficient peptization of the alumina. One skilled in the art will determine the appropriate amount and type of acid to provide the desired formable mixture.

[0034] The raw materials used in the catalyst preparation can be thoroughly mixed in a high shear mixer and then mixed with an aqueous non-metallic acid solution until a fairly hard mass / particle is obtained. This mass / particle can be extruded and / or formed into any suitable shape, including a cylinder, cube, star, trilobate, quadrilobate, pellet, pill, or sphere, by suitable mechanical means. In one embodiment, mixing is carried out in a high-intensity environment, such as that provided by a B&P Littleford mixer available from B&P Littleford, 1000 Hess Avenue, Saginaw, MI 48601. In another embodiment, mixing is carried out using an Eirich intense mixer, such as that provided by Maschinenfabrik GustavEirich Gmbh & Co KG in Hardheim, Germany. Mixing is carried out for a sufficient time to generate a fine, uniform mixture.

[0035] B. Materials

[0036] Solid aluminum hydroxide can be purchased from commercial suppliers. Non-limiting examples of solid aluminum hydroxide can include bayerite, new aluminum trihydrate, amorphous aluminum hydroxide, boehmite, pseudo-boehmite or a mixture thereof. In some aspects, solid aluminum hydroxide can include crystalline aluminum trihydroxide, crystalline aluminum oxide hydroxide or gel-like aluminum hydroxide or a mixture thereof. Crystallized aluminum trihydroxide can be 90wt%-100wt% of the solid aluminum hydroxide. For example, solid aluminum hydroxide can include 90wt%, 91wt%, 92wt%, 93wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%, 100wt% or any value or range therebetween of the crystalline aluminum trihydroxide. Solid aluminum hydroxide can include 0wt%-10wt% of crystalline aluminum oxide hydroxide or gel-like aluminum hydroxide, with the remainder being crystalline aluminum trihydroxide. For example, the solid aluminum hydroxide can comprise 0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt% or any range or value therebetween of crystalline aluminum oxide hydroxide. For example, the solid aluminum hydroxide can comprise 0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt% or any range or value therebetween of gelatinous aluminum hydroxide. In some cases, the solid aluminum hydroxide can comprise 90-99.9 wt% of crystalline aluminum trihydroxide and 0.1 wt%-10 wt% of crystalline aluminum oxide hydroxide. In another example, the solid aluminum hydroxide can comprise 90-99.9 wt% of crystalline aluminum trihydroxide and 0.1 wt%-10 wt% of gelatinous aluminum hydroxide. In another example, the solid aluminum hydroxide may comprise 90-99.9 wt% of solid crystalline aluminum trihydroxide and 0.1 wt%-10 wt% of crystalline aluminum oxide hydroxide or 0.1 wt%-10 wt% of gelatinous aluminum hydroxide. Non-limiting examples of crystalline aluminum trihydroxide may include bayerite, neoaluminum trihydrate, or a mixture thereof. Non-limiting examples of crystalline aluminum oxide hydroxide or gelatinous aluminum hydroxide or a mixture thereof may include boehmite, amorphous aluminum hydroxide, pseudo-boehmite, or a mixture thereof.

[0037] Non-limiting examples of water-insoluble chromium (III) oxide sources can include chromium (III) oxide and chromium (III) hydroxide, or mixtures thereof.

[0038] Alkali metal oxide sources (e.g., sodium oxide sources, lithium oxide sources, etc.) can be purchased from commercial sources. A non-limiting example of a sodium oxide source is a sodium salt. Specific examples of sodium oxide sources can include sodium acetate, sodium bicarbonate, sodium carbonate, sodium formate, sodium hydroxide, sodium metasilicate, sodium nitrate, sodium nitrite, etc. A non-limiting example of a lithium oxide source is a lithium salt. Specific examples of a lithium oxide source can include lithium acetate, lithium carbonate, lithium formate, lithium hydroxide, lithium nitrate, etc. Although not wishing to be bound by any theory, it is believed that the subsequently formed lithium oxide stabilizes the defect sites in the alumina.

[0039] The alkaline earth metal oxide source may include a barium oxide source, a strontium oxide source, or a mixture thereof. Non-limiting examples of barium oxide sources may include barium salts and barium oxide. Specific examples of barium oxide sources may include barium oxide, barium acetate, barium bicarbonate, barium carbonate, barium formate, barium hydroxide, barium nitrate, barium nitrite, and the like. Non-limiting examples of strontium oxide sources may include strontium salts and strontium oxide. Specific examples of strontium oxide sources may include strontium oxide, strontium acetate, strontium bicarbonate, strontium carbonate, strontium formate, strontium hydroxide, strontium nitrate, strontium nitrite, and the like.

[0040] Lanthanum oxide sources can be purchased from commercial sources. Non-limiting examples of lanthanum oxide sources can include lanthanum salts and lanthanum oxide. Specific examples of lanthanum oxide sources can include lanthanum oxide, lanthanum acetate, lanthanum bicarbonate, lanthanum carbonate, lanthanum formate, lanthanum hydroxide, lanthanum nitrate, and the like.

[0041] The silica source can be purchased from commercial sources.Non-limiting examples of silica sources can include sodium silicate, colloidal silicon dioxide, orthosilicic acid, or mixtures thereof.

[0042] C. Systems and Methods for Dehydrogenating Alkanes

[0043] Figure 1 A schematic diagram of a system for dehydrogenating alkanes is described. System 100 can include an inlet 102 for an alkane feed, a reaction zone 104 (e.g., a continuous flow reactor selected from a fixed bed reactor, a fluidized bed reactor, or a moving bed reactor) configured to be in fluid communication with the inlet 102, and an outlet 106 configured to be in fluid communication with the reaction zone 104 and configured to remove a product stream from the reaction zone. Reaction zone 104 can include a dehydrogenation catalyst 108 manufactured by the method of the present invention. The alkane feed can enter reaction zone 104 via inlet 102. In some embodiments, the reactant feed stream can include an inert gas (e.g., nitrogen or argon). Product stream can be removed from reaction zone 104 via outlet 106. Product streams comprising the alkanes (olefins) of dehydrogenation can be sent to other processing units, storage, and / or transportation.

[0044] The system 100 may include one or more heating and / or cooling devices (e.g., insulators, electric heaters, jacketed heat exchangers in the wall) or controllers (e.g., computers, flow valves, automatic valves, etc.) that can be used to control the reaction temperature and pressure of the reaction mixture. Although only one reactor is shown, it should be understood that multiple reactors can be housed in a unit, or multiple reactors can be housed in a reactor unit. The temperature, pressure, and gas hourly space velocity (GHSV) can vary depending on the reaction being performed and are within the capabilities of the person performing the reaction (e.g., an engineer or chemist).

[0045] Example

[0046] The present invention will be described in more detail by way of specific examples. The following examples are provided for illustrative purposes only and are not intended to limit the present invention in any way. Those skilled in the art will readily recognize that multiple noncritical parameters can be changed or adjusted to produce substantially the same result.

[0047] Catalyst characterization

[0048] Surface area measurements were performed using a Micromeritics Tristar surface area and porosity analyzer. Prior to measurement, the catalyst sample (about 200 mg) was evacuated at 300°C for 2 hours to remove physically adsorbed water and subjected to N2 physical adsorption at -196°C.

[0049] In the CuKa equipped with Ni filter ( Powder X-ray diffraction (XRD) patterns were obtained on a Rigaku-Miniflex 600 X-ray diffractometer equipped with 40 kV, 30 mA (40 kV, 30 mA) radiation and a graphite crystal monochromator. Data were collected over a 2θ range of 29°-41° using a step size of 0.02° and a scan rate of 2° / min. Crystalline phases were identified by reference to the Joint Committee on Powder Diffraction Standards (JCPDS) database or its successor, the International Centre for Diffraction Data (ICDD).

[0050] Temperature-programmed reduction (TPR) experiments were performed on an Autochem 2920 (Micromeritics) instrument. Prior to TPR analysis, the catalyst sample (approximately 100 mg) was pretreated at 400° C. for 30 minutes by passing pure argon (50 mL / min) to remove physically adsorbed water. After pretreatment, the sample was cooled to 50° C., and 10% hydrogen in argon was passed through the sample, and the sample was heated to 600° C. at 10° C. / min while recording data.

[0051] Example 1 (Comparative catalyst containing Cr / Na / Al)

[0052] A catalyst consisting of 20 wt% Cr2O3, 0.40 wt% Na2O and 79.6 wt% Al2O3 was prepared. Bayerite (2487.5 g, Pural BT, SASOL) and chromium (III) oxide (400 g, ) were mixed in an Eirich mixer (EL-5 Profi Plus) for 10 minutes. An aqueous nitric acid solution (462 mL, 25 wt%) containing 21.9 g of sodium nitrate dissolved therein was added to the mixer and mixed for 10 minutes. The resulting blend was aged at 25° C. for 1 hour and then formed into cylindrical extrudates (3.5 mm diameter) using an ETP1 Bonnot laboratory extruder, dried at 70° C. and then at 120° C. for 12 hours, calcined in a muffle furnace at 600° C. in air for 2 hours, and cooled to room temperature without external cooling. The surface area of ​​the catalyst was 230 m 2 The CrO3 content calculated from TPR was 3.3 wt%.

[0053] Example 2 (Catalyst of the present invention containing Cr / Na / Al)

[0054] A catalyst composed of 20 wt% Cr2O3, 0.4 wt% Na2O and 79.6 wt% Al2O3 was prepared as in Example 1, except that the sample was calcined at 850°C under nitrogen. The surface area of ​​this catalyst was 139.8 m 2 The CrO3 content calculated from TPR was 1.2 wt%.

[0055] Example 3 (Catalyst of the present invention containing Cr / Na / Al)

[0056] A catalyst composed of 20 wt% Cr2O3, 0.4 wt% Na2O and 79.6 wt% Al2O3 was prepared as in Example 1, except that the sample was calcined at 850°C in air. The surface area of ​​this catalyst was 89.6 m 2The CrO3 content calculated from TPR was 1.5 wt%.

[0057] Example 4 (Catalyst of the present invention containing Cr / Na / Li / Al)

[0058] The composition of the catalyst of this embodiment is 20 wt% Cr2O3, 0.43 wt% Na2O, 0.25 wt% Li2O and 79.32 wt% Al2O3. Bayerite (2408.6 g, Pural BT, SASOL), chromium (III) oxide (412 g, ) and pseudo-boehmite (128 g, PBAM-05, Chika Pvt. Ltd.) were mixed in an Eirich mixer (EL-5 Profi Plus) for 10 minutes. An aqueous nitric acid solution (476 ml, 25 wt %) containing sodium nitrate (24.3 g) and lithium nitrate (24.3 g) dissolved therein was added to the mixer and mixed for 10 minutes. The obtained blend was aged at 25° C. for 1 hour and then formed into cylindrical extrudates (3.5 mm diameter) using an ETP1 Bonnot laboratory extruder, dried at 70° C. and then at 120° C. for 12 hours, calcined at 850° C. in air in a muffle furnace for 2 hours, and cooled to room temperature without external cooling. The surface area of ​​this catalyst was 90.2 m 2 The CrO3 content calculated from TPR was 1.5 wt%.

[0059] Example 5 (Catalyst of the present invention containing Cr / Na / Li / Al)

[0060] A catalyst having a composition of 20 wt% Cr2O3, 0.43 wt% Na2O, 0.25 wt% Li2O and 79.32 wt% Al2O3 was prepared in the same manner as in Example 4, except that the calcination was carried out at 900°C. The surface area of ​​this catalyst was 60.8 m 2 The CrO3 content calculated from TPR was 1.2 wt%.

[0061] Example 6 (Catalyst containing Cr / Na / Li / Ba / Al of the present invention)

[0062] A catalyst composed of 20 wt% Cr2O3, 0.43 wt% Na2O, 0.25 wt% Li2O, 1.78 wt% BaO and 77.54 wt% Al2O3 was prepared. Bayerite (2286.1 g, PuralBT, SASOL), chromium (III) oxide (400 g, ), pseudoboehmite (121.4 g, PBAM-05, Chika Pvt. Ltd.) and barium nitrate (60.8 g) were mixed in an Eirich mixer (EL-5 Profi Plus) for 10 minutes. An aqueous nitric acid solution (463 ml, 25 wt %) containing sodium nitrate (23.6 g) and lithium nitrate (22.8 g) dissolved therein was added to the mixer and mixed for 10 minutes. The obtained blend was aged at 25° C. for 1 hour and then formed into cylindrical extrudates (3.5 mm diameter) using an ETP1 Bonnot laboratory extruder, dried at 70° C. and then at 120° C. for 12 hours, calcined at 850° C. in air in a muffle furnace for 2 hours and cooled to room temperature without external cooling. The surface area of ​​this catalyst was 90.7 m 2 The CrO3 content calculated from TPR was 2.1 wt%.

[0063] Example 7 (Comparative Catalyst Containing Cr / Na / Li / Ba / Al)

[0064] A comparative catalyst having a composition of 20 wt% Cr2O3, 0.43 wt% Na2O, 0.25 wt% Li2O, 1.78 wt% BaO, and 77.54 wt% Al2O3 was prepared. Bayerite (2829.1 g, Pural BT, SASOL), pseudoboehmite (148.9 g, PBAM-05, Chika Pvt. Ltd.), and barium nitrate (76.24 g) were mixed in an Eirich mixer (EL-5 Profi Plus) for 10 minutes. A nitric acid aqueous solution (500 mL, 15 wt%) containing lithium nitrate (28.59 g) dissolved therein was added to the mixer and mixed for 10 minutes. The obtained blend was aged at 25°C for 1 hour and then formed into cylindrical extrudates (3.5 mm diameter) using an ETP1 Bonnot laboratory extruder, dried at 70°C and then at 120°C for 12 hours, calcined in a muffle furnace at 850°C in air for 2 hours and cooled to room temperature without external cooling. The calcined alumina extrudates (250 g) were impregnated with an aqueous solution containing chromium (VI) oxide (78 g) and sodium dichromate dihydrate (7 g) to incipient wetness. The wet extrudates were aged at 25°C in a closed container for 12 hours. The sample was dried at 120°C for 6 hours and calcined in a muffle furnace at 750°C in air for 2 hours and cooled to room temperature without external cooling. The surface area of ​​this catalyst was 83.6 m 2 The CrO3 content calculated from TPR was 2.5 wt%.

[0065] Example 8 (Catalyst of the present invention containing Cr / Na / La / Al)

[0066] The catalyst of the present invention was prepared with a composition of 25.2 wt% Cr2O3, 1 wt% Na2O, 0.5 wt% La2O3 and 73.3 wt% Al2O3. Bayerite (2267.13 g, Pural BT, SASOL), chromium (III) oxide (527.62 g, ) and pseudo-boehmite (119.32 g, PBAM-05, Chika Pvt. Ltd.) were mixed in an Eirich mixer (R-02) for 10 minutes. An aqueous nitric acid solution (660 mL, 25 wt %) containing sodium nitrate (57.88 g) and lanthanum nitrate hexahydrate (28.05 g) dissolved therein was added to the mixer and mixed for 18 minutes. The resulting blend was aged at 25° C. for 1 hour and then formed into cylindrical extrudates (3.5 mm diameter) using an ETP-1 Bonnot type laboratory extruder, dried at 70° C. and then at 120° C. for 12 hours, calcined in air at 800° C. in a muffle furnace for 2 hours, and cooled to room temperature without external cooling.

[0067] Example 9 (Catalyst of the present invention containing Cr / Na / La / Al)

[0068] A catalyst of the present invention having a composition of 25 wt% Cr2O3, 1 wt% Na2O, 1 wt% La2O3, and 73 wt% Al2O3 was prepared using the method of Example 8, except that the amounts of the various components were adjusted. Specifically, Example 9 used the following amounts of each component: 2246.13 g of bayerite (Pural BT, SASOL), 522.73 g of chromium(III) oxide, 118.22 g of pseudo-boehmite, 550 mL of nitric acid, 57.35 g of sodium nitrate, and 55.58 g of lanthanum nitrate hexahydrate.

[0069] Example 10 (Catalyst of the present invention containing Cr / Na / La / Al)

[0070] A catalyst of the present invention having a composition of 24.5 wt% Cr2O3, 1 wt% Na2O, 2.9 wt% La2O3, and 71.5 wt% Al2O3 was prepared using the method of Example 8, except that the amounts of the various components were adjusted. Specifically, Example 10 used the following amounts of each component: 2165.88 g of bayerite, 504.05 g of chromium(III) oxide, 113.99 g of pseudo-boehmite, 616 mL of nitric acid, 55.30 g of sodium nitrate, and 160.78 g of lanthanum nitrate hexahydrate.

[0071] Example 11 (Catalyst of the present invention containing Cr / Na / La / Ba / Al)

[0072] The catalyst of the present invention was prepared with a composition of 25 wt% Cr2O3, 1.0 wt% Na2O, 0.74 wt% BaO, 0.89 wt% La2O3 and 72.4 wt% Al2O3. Bayerite (2134.4 g, PuralBT, SASOL), chromium (III) oxide (500 g, ), pseudo-boehmite (112.7 g, PBAM-05, Chika Pvt. Ltd.) and barium nitrate (25.2 g) were mixed in an Eirich mixer (EL-5 Profi Plus) for 10 minutes. An aqueous nitric acid solution (463 mL, 25 wt %) containing sodium nitrate (54.9 g) and lanthanum nitrate hexahydrate (47.2 g) dissolved therein was added to the mixer and mixed for 10 minutes. The obtained blend was aged at 25° C. for 1 hour and then formed into cylindrical extrudates (3.5 mm diameter) using an ETP1 Bonnot laboratory extruder, dried at 70° C. and then at 120° C. for 12 hours, calcined in air at 800° C. in a muffle furnace for 2 hours and cooled to room temperature without external cooling. The surface area of ​​this catalyst is 94.9 m 2 / g.

[0073] Example 12 (Comparative Catalyst Containing Cr / Na / La / Al)

[0074] A comparative catalyst of 25 wt% Cr2O3, 1.0 wt% Na2O, 3 wt% La2O3 and 71 wt% Al2O3 was prepared. Bayerite (2850 g, Pural BT, SASOL) and pseudoboehmite (150 g, PBAM-05, Chika Pvt. Ltd.) were mixed in an Eirich mixer (R-02) for 10 minutes. A nitric acid aqueous solution (580 ml, 20 wt%) was added to the mixer and mixed for 15 minutes. The resulting blend was aged at 25°C for 1 hour and then formed into cylindrical extrudates (3.5 mm diameter) using an ETP1 Bonnot type laboratory extruder, dried at 70°C and subsequently at 120°C for 12 hours, calcined in air at 550°C in a muffle furnace for 2 hours, and cooled to room temperature without external cooling. The prepared alumina extrudates (96 g) were impregnated with an aqueous solution containing lanthanum nitrate hexahydrate (10.63 g) to obtain incipient wetness. The wet extrudates were aged at 25° C. in a sealed container for 12 hours. The sample was then dried at 120° C. for 6 hours and calcined in a muffle furnace in air at 800° C. for 2 hours and cooled to room temperature without external cooling. The calcined modified alumina extrudates (74 g) were impregnated with an aqueous solution containing chromium (VI) oxide (29.67 g) and sodium dichromate dihydrate (4.81 g) to obtain incipient wetness. The wet extrudates were aged at 25° C. in a sealed container for 12 hours. The sample was then dried at 120° C. for 6 hours and calcined in a muffle furnace in air at 750° C. for 2 hours and cooled to room temperature without external cooling.

[0075] Example 13 (Comparative Catalyst Containing η Alumina and Cr / Na / La)

[0076] An alumina support with η-alumina was prepared for catalyst preparation. Bayerite (3125 g, Pural BT, SASOL) was mixed in an Eirich mixer (EL-5 Profi Plus) for 10 minutes. Aqueous nitric acid solution (520 mL, 15 wt%) was added to the mixer and mixed for 9 minutes. The blend obtained was aged at 25° C. for 1 hour and then formed into cylindrical extrudates (3.5 mm diameter) using an ETP1 Bonnot laboratory extruder. The mixture was dried at 70° C. and subsequently at 120° C. for 12 hours, calcined at 600° C. in air in a muffle furnace for 2 hours, and cooled to room temperature without external cooling.

[0077] Using this alumina support, a comparative catalyst of composition 25 wt% Cr2O3, 1.0 wt% Na2O, 1 wt% La2O3 and 73 wt% Al2O3 was prepared. The calcined alumina extrudates (73 g) were impregnated with an aqueous solution containing chromium (VI) oxide (9.7 g), lanthanum oxide (1 g) and sodium dichromate dihydrate (2.5 g) to incipient wetness. The wet extrudates were aged in a sealed container at 25°C for 12 hours. The sample was dried at 120°C for 6 hours and calcined in a muffle furnace at 750°C in air for 2 hours and cooled to room temperature without external cooling. The surface area of ​​this catalyst was 88.8 m 2 / g.

[0078] Example 14 (Comparative Catalyst Containing η Alumina and γ Alumina and Cr / Na / La)

[0079] An alumina support with 95 wt% of η alumina and 5 wt% of gamma alumina was prepared for catalyst preparation. Bayerite (2969 g, PuralBT, SASOL) and pseudoboehmite (139 g, PBAM-05, Chika Pvt. Ltd.) were mixed in an Eirich mixer (EL-5 ProfiPlus) for 10 minutes. Aqueous nitric acid solution (520 mL, 15 wt%) was added to the mixer and mixed for 8.5 minutes. The resulting blend was aged at 25°C for 1 hour and then formed into cylindrical extrudates (3.5 mm diameter) using an ETP1 Bonnot laboratory extruder, dried at 70°C subsequently at 120°C for 12 hours, calcined at 600°C in air for 2 hours in a muffle furnace, and cooled to room temperature without external cooling.

[0080] A comparative catalyst of composition 25 wt% Cr2O3, 1.0 wt% Na2O, 1 wt% La2O3 and 73 wt% Al2O3 was prepared using alumina extrudates. The calcined alumina extrudates (73 g) were impregnated with an aqueous solution containing chromium (VI) oxide (29.7 g), lanthanum oxide (1 g) and sodium dichromate dihydrate (2.5 g) to achieve incipient wetness. The wet extrudates were aged in a sealed container at 25°C for 12 hours. The sample was dried at 120°C for 6 hours and calcined in a muffle furnace in air at 750°C for 2 hours and cooled to room temperature without external cooling. The surface area of ​​this catalyst was 94.9 m 2 / g.

[0081] Example 15 (Analysis)

[0082] The powder XRD patterns of the catalysts of Example 3, Example 4 and Example 6 are as follows: Figure 2As shown. The top diffraction pattern is a catalyst of the present invention comprising 20 wt% Cr2O3, 0.40 wt% Na2O and 79.6 wt% Al2O3, and calcined at 850°C in air. The middle diffraction pattern is a catalyst of the present invention comprising 20 wt% Cr2O3, 0.43 wt% Na2O, 0.25 wt% Li2O and 79.32 wt% Al2O3, Al2O3 originating from bayerite and pseudoboehmite, and calcined at 850°C in air. The bottom diffraction pattern is a catalyst of the present invention comprising 20 wt% Cr2O3, 0.43 wt% Na2O, 0.25 wt% Li2O, 1.78 wt% BaO and 77.54 wt% Al2O3, Al2O3 originating from bayerite and pseudoboehmite, and calcined at 850°C in air. In the inventive Example 3 catalyst, the alumina is primarily present in the theta alumina form, the inventive Example 4 catalyst has a low-theta alumina form, and the inventive Example 6 catalyst has no theta alumina. Therefore, from these results, it can be determined that (a) the presence of lithium oxide in the Example 4 catalyst and (b) the presence of lithium oxide and barium oxide in the Example 6 catalyst stabilize the alumina and prevent phase changes. Therefore, compared to the catalysts of Examples 3 and 4, the inventive Example 6 catalyst exhibits higher thermal stability. Catalysts with higher thermal stability are expected to have higher stability in isobutane dehydrogenation.

[0083] Example 16 (Catalyst Test)

[0084] The dehydrogenation activity of the prepared catalyst was measured in a tubular fixed-bed quartz reactor at atmospheric pressure. The catalyst loading and reactor details were as follows: catalyst weight = 8.5 g, catalyst particle size = ~3 mm, inert quartz weight = 8.5 g, inert quartz chips = 0.4-0.5 mm, reactor inner diameter = 16 mm, reactor outer diameter = 19 mm. The catalyst and inert quartz were divided into equal weight portions and then loaded into the reactor by mixing the catalyst and inert materials. Isobutane (99.9% by volume) was used as the feed. Quartz chips with a size of 1-1.4 mm were loaded above the catalyst bed. Nitrogen purge was used between the dehydrogenation, catalyst regeneration / oxidation and reduction steps with hydrogen. The total feed flow in the dehydrogenation step corresponded to a GHSV of 600 mL h -1 g -1. The reactor outlet gas was analyzed by an online gas chromatograph (Agilent 6890) equipped with a flame ionization detector for hydrocarbon analysis and a thermal conductivity detector for hydrogen analysis. The reactant and product flow rates were measured using a Ritter-type wet gas flow meter. The reactor was operated at atmospheric pressure and in a circulation mode with the following steps: 1) the catalyst was oxidized with air for 20 minutes, with a starting temperature of 650°C; 2) the catalyst was purged with nitrogen at 650°C for 3 minutes; 3) the catalyst was reduced with H2 for 6 minutes, with a starting temperature of 650°C; 4) cooled from 650°C to 585°C under nitrogen, and maintained at a temperature of 585°C for 30 minutes;

[0085] 5) Dehydrogenate isobutane for 21 minutes, starting at 585°C. 6) Analyze the reactor outlet gas composition by gas chromatography (GC) 20 minutes after the start of the isobutane feed. Steps 1-6 were repeated 30 times. Catalyst performance data (10-cycle average with standard deviation) after catalyst stabilization are given in Tables 1 and 2.

[0086] Example 17 (Catalyst Test)

[0087] Catalyst stability evaluation was performed using an artificial accelerated aging procedure in a cyclic operating mode. The cycles consisted of H2-N2-isobutane-N2-air flow phases of varying duration. Aging was performed at 820°C for 72 hours. Catalyst stability evaluation parameters included catalyst weight = 8.5 g, isobutane GHSV = 400 mL h -1 g -1 , and an air to isobutane volume ratio of 2. The following steps were performed: 1) oxidizing the catalyst under air for 15 minutes; 2) purging the catalyst with nitrogen for 3 minutes; 3) reducing the catalyst with H2 for 6 minutes; 4) purging the catalyst with nitrogen for 3 minutes; 5) flowing isobutane for 3 minutes; and 6) purging the catalyst with nitrogen for 3 minutes. After aging, catalyst performance was performed under the aforementioned cycle mode.

[0088] The properties of the catalysts are listed in Tables 1 and 2. The results in Table 1 show that the catalyst prepared by calcining at 850°C in air exhibited higher isobutylene selectivity than the catalyst calcined at 600°C in air. Similarly, the catalyst prepared by calcining at 850°C in air exhibited higher isobutylene selectivity than the catalyst calcined at 850°C in nitrogen.

[0089] Table 1

[0090]

[0091] Table 2

[0092]

[0093] In addition, when comparing the performance of the catalyst of Example 6 of the present invention with the comparative catalyst of Example 7, the catalyst of Example 10 of the present invention with the comparative catalyst of Example 12, and the catalyst of Example 9 of the present invention with the comparative catalysts of Examples 13 and 14, it can be determined that the catalyst prepared by the method of the present invention exhibits higher stability compared with the catalyst prepared according to the comparative example.

[0094] Although the embodiments of the present application and their advantages have been described in detail, it should be understood that different changes, substitutions and variations can be made herein without departing from the subject matter and scope of the embodiments defined by the appended claims. In addition, the scope of the present application is not intended to be limited to the specific embodiments of the process, machine, manufacture, composition of matter, device, method and step described in the specification. As those skilled in the art will readily understand from the above disclosure, the process, machine, manufacture, composition of matter, device, method or step of performing the function substantially the same as the corresponding embodiment described herein or realizing substantially the same result can be used that currently exists or is developed later. Therefore, the purpose of the appended claims is to include such process, machine, manufacture, composition of matter, device, method or step within their scope.

Claims

1. A method for preparing an alkane dehydrogenation catalyst, the method comprising: (a) extruding and / or tableting a formable mixture comprising solid aluminum hydroxide, a water-insoluble source of chromium(III) oxide, a source of alkali metal oxide, and a non-metallic acid, preferably an aqueous non-metallic acid, to form a catalyst precursor; (b) drying the catalyst precursor; and (c) calcining the dried catalyst precursor at a temperature of 700° C. to 1000° C. to form an alkane dehydrogenation catalyst, wherein the alkane dehydrogenation catalyst comprises 10 wt % to 40 wt % of chromium (III) oxide (Cr2O3), 0.1 wt % to 5 wt % of an alkali metal oxide and 60 wt % to 90 wt % of aluminum oxide (Al2O3).

2. The method of claim 1, further comprising calcining the catalyst in the presence of air.

3. The method according to any one of claims 1 to 2, wherein the alkali metal oxide source comprises a sodium oxide source, a lithium oxide source, a cesium oxide source, a potassium oxide source or a mixture thereof, preferably sodium oxide.

4. The method according to claim 3, wherein the catalyst comprises: 60wt%-90wt% Al2O3; 10 wt% to 40 wt% Cr2O3; and 0.1wt%-5wt% Na2O.

5. The method according to claim 4, wherein the catalyst comprises: 60wt%-90wt% Al2O3; 10wt%-40wt% Cr2O3; 0.1 wt% to 5 wt% Na2O; and 0.1 wt% to 5 wt% Li2O, preferably 0.1 wt% to 3 wt% Li2O.

6. The method according to any one of claims 1 to 5, wherein the formable mixture further comprises an alkaline earth metal oxide source, and the catalyst comprises 0.1 wt% to 20 wt% of an alkaline earth metal oxide source, wherein the alkaline earth metal oxide source comprises a barium oxide source (BaO) and / or a strontium oxide source (SrO), and the catalyst comprises BaO, SrO or a combination thereof, preferably BaO.

7. The method according to claim 1, wherein the catalyst comprises: 60wt%-90wt% Al2O3; 10wt%-40wt% Cr2O3; 0.1wt%-5wt% Na2O; 0.1 wt% to 20 wt% BaO, preferably 0.1 wt% to 5 wt% BaO; and Optionally 0.1 wt% to 5 wt% Li2O, preferably 0.1 wt% to 3 wt% Li2O.

8. The method according to any one of claims 1 to 4, wherein the formable mixture further comprises a lanthanide oxide source, the lanthanide oxide source comprising a lanthanum oxide source, a cerium oxide source or a mixture thereof, and the catalyst comprises 0.1 wt% to 20 wt% of lanthanum oxide (La2O3), preferably 0.1 wt% to 5 wt% of La2O3.

9. The method according to claim 8, wherein the catalyst comprises: 60wt%-95wt% Al2O3; 5wt%-40wt% Cr2O3; 0.1 wt% to 5 wt% Na2O; and 0.1wt%-20wt% La2O3, preferably 0.1wt%-5wt% La2O3.

10. The method according to any one of claims 8-9, wherein the formable mixture further comprises an alkaline earth metal oxide source, and the catalyst comprises 0.1 wt%-20 wt% of an alkaline earth metal oxide, wherein the alkaline earth metal oxide source comprises a barium oxide source and / or a strontium oxide source, and the catalyst comprises BaO, SrO or a combination thereof, preferably BaO.

11. The method according to claim 10, wherein the catalyst comprises: 60wt%-90wt% Al2O3; 10wt%-40wt% Cr2O3; 0.1wt%-5wt% Na2O; 0.1 wt% to 20 wt% of BaO, preferably 0.1 wt% to 5 wt%; and 0.1wt%-20wt% La2O3, preferably 0.1wt%-5wt% La2O3.

12. The method of any one of claims 1 to 4, wherein the shapeable mixture further comprises a silica source, and the catalyst comprises 0.1 wt% to 5 wt% silica.

13. The method of any one of claims 1-12, wherein the solid aluminum hydroxide comprises crystalline aluminum trihydroxide, and wherein the crystalline aluminum trihydroxide comprises bayerite, neoalumina, or a mixture thereof.

14. The method of any one of claims 1-12, wherein the solid aluminum hydroxide comprises crystalline aluminum trihydroxide, crystalline aluminum oxide hydrate, gelatinous aluminum hydroxide, or a mixture thereof, wherein the crystalline aluminum trihydroxide comprises bayerite, neoalumina trihydrate, or a combination thereof, wherein the crystalline aluminum oxide hydrate comprises boehmite, and wherein the gelatinous aluminum hydroxide comprises amorphous aluminum hydroxide, pseudoboehmite, or a combination thereof, and wherein the water-insoluble chromium (III) oxide source comprises chromium (III) oxide, chromium (III) hydroxide, or a combination thereof.

15. A method for dehydrogenating alkanes, comprising contacting a catalyst produced by the method of any one of claims 1 to 14 with an alkane composition to produce dehydrogenated alkanes.

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