Strontium-Catalyzed Boehmite Formation

Abstract

A strontium-catalyzed process for preparing boehmite comprises combining a strontium material, rapidly calcined boehmite trihydrate, and water to obtain an aqueous suspension; contacting the aqueous suspension with a water-soluble carbonate material; and heating the aqueous suspension to a temperature sufficient to form at least about 5 wt% boehmite for a period of time.

Description

Technical Field

[0001] The present technology relates to a method for preparing boehmite (AlOOH) and transition alumina from rapidly calcined gibbsite. In particular, the present technology relates to a strontium-catalyzed method for preparing boehmite. Summary of the Invention

[0002] In one aspect, the present technology provides a strontium-catalyzed method for preparing boehmite, which includes combining a strontium material, rapidly calcined gibbsite, and water to obtain an aqueous suspension; contacting the aqueous suspension with a water-soluble carbonate material; and heating the aqueous suspension to a temperature sufficient to form at least about 5 weight percent (“wt%”) of boehmite for a period of time.

[0003] In a related aspect, the present technology provides boehmite prepared according to the method described in any embodiment herein.

[0004] In another aspect, the present technology provides a method for preparing transition alumina, which includes: preparing boehmite via a strontium-catalyzed method; the method includes: combining a strontium material, rapidly calcined gibbsite, and water to obtain an aqueous suspension; contacting the aqueous suspension with a caustic material; and heating the aqueous suspension to a temperature sufficient to form at least about 5 wt% of boehmite for a period of time; and calcining the boehmite to form transition alumina.

[0005] In a related aspect, the present technology provides a transition alumina including SrAl2O4.

[0006] In another related aspect, the present technology provides a composition, which includes boehmite prepared according to the strontium-catalyzed method described in any embodiment herein or transition alumina prepared according to the method described in any embodiment herein, wherein the composition may be selected from fluid catalytic cracking (FCC) catalysts, Y-zeolites, FCC additives, emission control materials, cobalt catalyst supports, steam reforming catalysts, emission control catalysts, and catalyst supports for various chemical process conversion catalysts. Brief Description of the Drawings

[0007] Figure 1 X-ray diffraction (XRD) patterns of boehmite (AlOOH with SrCO3 and AlOOH alone) prepared according to an exemplary embodiment of the present technology.

[0008] Figure 2 XRD patterns of boehmite (γ-Al2O3 with SrCO3 and γ-Al2O3 alone) with SrCO3 and AlOOH) prepared according to an exemplary embodiment of the present technology.

[0009] Figure 3Graphical regions showing the fraction converted to AlOOH in the crystallization of La-doped boehmite subjected to rapid calcination at pH 5.5 and 9 (Comparative Example A).

[0010] Figure 4 Graphical regions showing the fraction converted to AlOOH in the crystallization of Sr-doped boehmite subjected to rapid calcination at pH 9. Detailed Description

[0011] The various embodiments are described below. It should be noted that the specific embodiments are not intended as an exhaustive description or as a limitation on the broader aspects discussed herein. An aspect described in connection with a particular embodiment is not necessarily limited to that embodiment and can be practiced with any other one or more embodiments.

[0012] As used herein, "about" will be understood by those of ordinary skill in the art and will vary somewhat depending on the context in which it is used. If there is a usage of a term that is not clear to those of ordinary skill in the art, "about" will mean up to plus or minus 10% of the particular term, taking into account the context in which the term is used.

[0013] Unless otherwise indicated herein or clearly contradicted by context, the terms "a", "an", and "the" and similar references used in the context of describing an element (especially in the context of the following claims) should be construed to cover both the singular and the plural. Unless otherwise indicated herein, the recitation of a range of values herein is merely intended as a shorthand method of referring individually to each separate value falling within the range, and each separate value is incorporated into the specification as if it were individually recited herein. Unless otherwise indicated herein or otherwise clearly contradicted by context, all methods described herein can be performed in any suitable order. Unless otherwise noted, the use of any and all examples or exemplary language (e.g., "such as") provided herein is merely intended to better illustrate the embodiments and does not pose a limitation on the scope of the claims. No language in this specification should be construed as indicating any non-claimed element as being essential.

[0014] The inventors surprisingly found a method for rapidly preparing undoped boehmite. In this method, it has been found that strontium compounds play a catalytic role in the formation of boehmite. As understood by those skilled in the art, rapidly calcined gibbsite can be converted into boehmite. As described in more detail herein, the present technology includes converting rapidly calcined gibbsite in an aqueous suspension in the presence of strontium acetate, and then treating the aqueous suspension with sodium carbonate. Surprisingly, the inventors found that under the process conditions described in any embodiment herein, the conversion of rapidly calcined gibbsite to boehmite occurs faster than via conventional approaches. Strontium carbonate can then be leached from boehmite to regenerate the strontium acetate solution, which can be reused with fresh rapidly calcined gibbsite to make more boehmite.

[0015] In addition, the inventors have found that the strontium-catalyzed boehmite crystallite size growth rate is fast compared to other methods. Without being bound by theory, it is believed that the morphology of the starting gibbsite is suboptimal. Gibbsite usually appears in the form of hexagonal plates with a width of about 10-40 microns across the hexagonal basal plane. Gibbsite with a more needle-like morphology is mostly less than 10 μm in diameter and may be preferred in the application of fast calcined gibbsite (FCG) hydration to fine-crystalline boehmite. In contrast, the inventors have found that the boehmite obtained according to the present method (i.e., the direct conversion of strontium-catalyzed FCG to boehmite) has a large crystallite size. Similarly, the transition alumina (e.g., γ-Al2O3) obtained from this type of boehmite has a large crystallite size. Large crystal γ-Al2O3 can be used in various settings. However, it is usually expensive to obtain such large crystal alumina using conventional methods such as autoclave methods. The methods currently claimed are superior to conventional methods because they use atmospheric conditions.

[0016] The strontium-catalyzed boehmite synthesis from flash-calcined gibbsite has several additional advantages. First, the process is faster than conventional methods for making undoped boehmite, such as the low-high pH swing process. In this comparative process, an acid such as acetic acid is added to the flash-calcined gibbsite to lower the pH of the suspension containing the flash-calcined gibbsite to a range of 3-4 before sodium carbonate is added to raise the pH to 9. In both cases, crystallization is carried out at 99°C. For the Sr-catalyzed process according to the present technology, the conversion of the flash-calcined gibbsite to AlOOH is 71.5±3.4% after 48 hours of AlOOH crystallization time at 99°C, but for the low-high pH swing process, the conversion of the flash-calcined gibbsite to AlOOH is only 65.4±2.0% at 48 hours.

[0017] Second, the strong Lewis acidity level provided by the strontium-catalyzed method is particularly low. After complete conversion to AlOOH and calcination to γ-alumina, the content of strong Lewis sites evaluated by pyridine FTIR is as low as about 10 μmol / g to about 25 μmol / g. The inventors have surprisingly found that the acidity level remains low when strontium is present in the composite material.

[0018] In one aspect, the present technology provides a strontium-catalyzed method for preparing boehmite, which includes combining a strontium material, rapidly calcined boehmite trihydrate, and water to obtain an aqueous suspension; contacting the aqueous suspension with a water-soluble carbonate material; and heating the aqueous suspension to a temperature sufficient to form at least about 5 weight percent (“wt%”) of boehmite based on the total weight of the solids and for a period of time.

[0019] In any of the embodiments disclosed herein, the strontium material may include a strontium salt. For example, in any of the embodiments herein, the strontium salt may include, but is not limited to, strontium carboxylate, strontium nitrate, strontium chloride, strontium bromide, strontium iodide, or a mixture thereof. In any of the embodiments disclosed herein, the strontium material may be a strontium carboxylate salt. Suitable strontium carboxylate salts may include, but are not limited to, strontium acetate, strontium formate, strontium lactate, strontium glycolate, strontium propionate, or a mixture thereof. In any of the embodiments disclosed herein, the strontium material may be strontium acetate.

[0020] In any of the embodiments disclosed herein, the water-soluble carbonate material may include, but is not limited to, carbonates, carbonate precursors, sodium bicarbonate, sodium ammonium carbonate, or a combination of two or more thereof. For example, in any of the embodiments disclosed herein, the carbonate may include, but is not limited to, sodium carbonate, potassium carbonate, ammonium carbonate, or a combination of two or more thereof. In some embodiments, the carbonate may be sodium carbonate. As used herein, “carbonate precursor” refers to a composition that decomposes to produce a carbonate. For example, in any of the embodiments disclosed herein, the carbonate precursor may be urea.

[0021] In any of the embodiments disclosed herein, the aqueous suspension may include a strontium material and rapidly calcined boehmite trihydrate in a weight ratio (strontium material: rapidly calcined boehmite trihydrate) of about 10:1 to about 1:10. Suitable weight ratios of the strontium material to the rapidly calcined boehmite trihydrate may include about 10:1, about 5:1, about 3:2, about 2:1, about 1:1, about 1:2, about 2:3, about 1:5, about 1:10, or any range including and / or between any two of these values. In any of the embodiments disclosed herein, the strontium material may be present in the aqueous suspension in an amount (i.e., concentration) below the saturation point of the strontium material in solution. For example, in any of the embodiments disclosed herein, the strontium material may be present in the aqueous suspension at a concentration below the saturation point of the strontium material and at a temperature between ambient temperature and about 110 °C.

[0022] In any of the embodiments disclosed herein, the aqueous suspension may comprise from about 1 wt% to about 40 wt% solids. By way of example, in any of the embodiments disclosed herein, the aqueous suspension may comprise about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 12 wt%, about 14 wt%, about 16 wt%, about 18 wt%, about 20 wt%, about 22 wt%, about 24 wt%, about 26 wt%, about 28 wt%, about 30 wt%, about 32 wt%, about 34 wt%, about 36 wt%, about 38 wt%, about 40 wt%, or any range including and / or between any two of these values. In any of the embodiments disclosed herein, the aqueous suspension may comprise from about 1 wt% to about 40 wt%, from about 10 wt% to about 30 wt%, from about 15 wt% to about 25 wt% solids, or any range including and / or between any two of the foregoing values.

[0023] In any of the embodiments disclosed herein, the method may further comprise heating the aqueous suspension to a temperature of from about 30 °C to about 110 °C prior to contacting the aqueous suspension with the caustic material. Suitable temperatures include, but are not limited to, about 30 °C, about 35 °C, about 40 °C, about 45 °C, about 50 °C, about 55 °C, about 60 °C, about 65 °C, about 70 °C, about 75 °C, about 80 °C, about 85 °C, about 90 °C, about 95 °C, about 99 °C, about 100 °C, about 105 °C, about 110 °C, or any range including and / or between any two of the foregoing values. By way of example, in any of the embodiments herein, the temperature may be from about 30 °C to about 110 °C, from about 45 °C to about 105 °C, from about 90 °C to about 99 °C, from about 95 °C to about 100 °C, or any range including and / or between any two of these values.

[0024] Heating can be carried out for a time sufficient to form boehmite in an amount of about 5 wt% based on the total weight of the solid. For example, heating can be carried out for a time sufficient to form boehmite in an amount of about 5 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 30 wt%, about 40 wt%, about 50 wt%, about 60 wt%, about 70 wt%, about 80 wt%, about 90 wt%, 100 wt% based on the total weight of the solid, or any range including and / or between any two of the foregoing values. In any of the embodiments disclosed herein, heating can continue for a duration of about 1 hour to about 2 weeks. Suitable durations can include but are not limited to about 1 hour, about 2 hours, about 4 hours, about 6 hours, about 8 hours, about 10 hours, about 12 hours, about 14 hours, about 16 hours, about 18 hours, about 20 hours, about 22 hours, about 1 day, about 2 days, about 4 days, about 6 days, about 8 days, about 10 days, about 14 days, or any range including and / or between any two of the foregoing values.

[0025] In any of the embodiments disclosed herein, the pH of the aqueous solution can be from about 7 to about 10. For example, in any of the embodiments herein, the pH of the aqueous solution can be about 7, about 7.5, about 8, about 8.5, about 9, about 9.5, about 10, or any range including and / or between any two of these values. In any of the embodiments disclosed herein, the pH can be from about 7 to about 10, from about 8 to about 10, from about 7.5 to about 9.5, from about 8 to about 9.5, from about 8.5 to about 9, or any range including and / or between any two of these values. In any of the embodiments disclosed herein, the pH of the aqueous suspension is from about 7 to about 10. In some embodiments, the pH can be about 9.

[0026] In any of the embodiments disclosed herein, the method can convert rapidly calcined boehmite to boehmite such that at least about 10 wt% to 100 wt% of boehmite is formed. For example, in any of the embodiments herein, at least about 10 wt%, about 12 wt%, about 14 wt%, about 16 wt%, about 18 wt%, about 20 wt%, about 22 wt%, about 24 wt%, about 26 wt%, about 28 wt%, about 30 wt%, about 32 wt%, about 34 wt%, about 36 wt%, about 38 wt%, about 40 wt%, about 42 wt%, about 44 wt%, about 46 wt%, about 48 wt%, about 50 wt%, about 52 wt%, about 54 wt%, about 56 wt%, about 58 wt%, about 60 wt%, about 62 wt%, about 64 wt%, about 66 wt%, about 68 wt%, about 70 wt%, about 72 wt%, about 74 wt%, about 76 wt%, about 78 wt%, about 80 wt%, about 82 wt%, about 84 wt%, about 86 wt%, about 88 wt%, about 90 wt%, about 92 wt%, about 94 wt%, about 96 wt%, about 98 wt%, 100 wt%, or any range including and / or between any two of these values.

[0027] In any of the embodiments disclosed herein, the strontium-catalyzed method of the present technology can have a faster microcrystal size growth rate relative to a non-strontium-catalyzed boehmite formation method. For example, relative to an uncatalyzed, lanthanum-catalyzed, or bismuth-catalyzed method, the strontium-catalyzed method can exhibit a faster boehmite microcrystal size growth rate.

[0028] Once the rapidly calcined boehmite is converted to obtain boehmite, the method can further include separating the boehmite from the aqueous suspension and optionally washing. In any of the embodiments disclosed herein, the method can further include removing the boehmite from the aqueous suspension. For example, in any of the embodiments disclosed herein, the method can include separating the boehmite from the aqueous suspension. Suitable separation techniques can include but are not limited to filtration, evaporation, spray drying, drying via a drum dryer, or a combination thereof. In any of the embodiments disclosed herein, the method can further include washing the boehmite after removal with a washing solution. Washing can be performed to remove sodium from the boehmite. In any of the embodiments disclosed herein, the washing solution can be water or an aqueous washing solution. In any of the embodiments disclosed herein, the washing solution can include an ammonium salt. Suitable ammonium salts can include but are not limited to ammonium nitrate, ammonium acetate, or a combination thereof.

[0029] In any of the embodiments disclosed herein, the microcrystal size of the boehmite obtained from the strontium-catalyzed method of the present technology can be about to about Suitable microcrystal sizes can include but are not limited to about about about about about about about about about about about about about about about about about about about about about or include and / or any range between any two of these values. In any embodiment disclosed herein, the crystallite size can be about to about about to about about to about or include and / or any range between any two of these values.

[0030] The boehmite formed according to the strontium-catalyzed method disclosed herein in any embodiment can include strontium in the form of strontium carbonate. Additionally or alternatively, in some embodiments, the method of the present technology can further include removing strontium from the boehmite. For example, in any embodiment disclosed herein, removing strontium carbonate from the boehmite can include combining the boehmite with water and a weak acid to obtain a reaction mixture; heating the reaction mixture to a temperature and for a period of time sufficient to convert the strontium carbonate to a strontium material, as disclosed herein in any embodiment; removing the boehmite from the reaction mixture; washing the boehmite with water; and drying the boehmite. In any embodiment disclosed herein, the weak acid can be selected from acetic acid, dilute nitric acid (e.g., nitric acid from about 0.0001 M to less than about 2 M), or combinations thereof.

[0031] As disclosed herein in any embodiment, removing strontium present as strontium carbonate from the boehmite can regenerate the strontium material. For example, combining boehmite that may contain strontium carbonate with acetic acid forms strontium acetate. The strontium acetate recovered during the removal process can be used as the strontium material, as disclosed herein in any embodiment.

[0032] As disclosed in any embodiment herein, the boehmite can be undoped boehmite. Accordingly, the method can further include doping the boehmite with one or more of a rare earth element, tin or its oxide, bismuth or its oxide, an alkaline earth element, or a mixture of two or more thereof. Suitable rare earth elements can include yttrium, scandium, praseodymium, neodymium, promethium, samarium, europium, terbium, dysprosium, holmium, erbium, thulium, lutetium, ytterbium, gadolinium, cerium, lanthanum, or a mixture of any two or more thereof. In any embodiment disclosed herein, the rare earth element can be lanthanum. Suitable alkaline earth elements can be selected from magnesium, calcium, strontium, or barium. For example, in any embodiment herein, the alkaline earth element can be strontium. In any embodiment disclosed herein, the boehmite can be strontium-doped boehmite.

[0033] In a related aspect, the present technology provides a boehmite prepared according to the method as described in any embodiment herein.

[0034] In another aspect, the present technology provides a method for preparing transition alumina, which includes: (i) preparing boehmite via a strontium-catalyzed method, wherein the strontium-catalyzed method of step (i) includes: combining a strontium material, rapidly calcined boehmite trihydrate, and water to obtain an aqueous suspension; contacting the aqueous suspension with a caustic material; and heating the aqueous suspension to a temperature sufficient to form at least about 5 wt% boehmite based on the total weight of the solids and for a period of time; and (ii) calcining the boehmite to form transition alumina. For example, in any embodiment herein, the boehmite can be obtained via the strontium-catalyzed method as disclosed in any embodiment herein.

[0035] In any embodiment disclosed herein, the calcination can be carried out at a temperature of about 500 °C to about 1000 °C. Suitable calcination temperatures can include but are not limited to about 500 °C, about 550 °C, about 600 °C, about 650 °C, about 700 °C, about 750 °C, about 800 °C, about 850 °C, about 900 °C, about 950 °C, about 1000 °C, or any range including and / or between any two of these values. For example, in any embodiment disclosed herein, the calcination temperature can be about 500 °C to about 1000 °C, about 550 °C to about 750 °C, about 550 °C to about 650 °C, about 750 °C to about 900 °C, about 750 °C to about 850 °C, or any range including and / or between any two of these values.

[0036] In any embodiment disclosed herein, the transition alumina can include but is not limited to γ-Al2O3, η-Al2O3, δ-Al2O3, θ-Al2O3, κ-Al2O3, χ-Al2O3, or a combination of two or more thereof. In any embodiment disclosed herein, the transition alumina can include γ-alumina, χ-alumina, or a mixture thereof. In any embodiment disclosed herein, the transition alumina can include γ-alumina.

[0037] The transition alumina obtained according to the method disclosed herein may have a reduced number of Lewis acid sites. In any embodiment disclosed herein, the Lewis acidity of the transition alumina may be less than or equal to about 120 μmol / g. For example, in any embodiment disclosed herein, the Lewis acidity of the transition alumina may be from about 120 μmol / g to about 10 μmol / g. In any embodiment disclosed herein, the Lewis acidity of the transition alumina may be about 10 μmol / g, about 11 μmol / g, about 12 μmol / g, about 13 μmol / g, about 14 μmol / g, about 15 μmol / g, about 16 μmol / g, about 17 μmol / g, about 18 μmol / g, about 19 μmol / g, about 20 μmol / g, about 25 μmol / g, about 30 μmol / g, about 35 μmol / g, about 40 μmol / g, about 45 μmol / g, about 50 μmol / g, about 55 μmol / g, about 60 μmol / g, about 65 μmol / g, about 70 μmol / g, about 80 μmol / g, about 85 μmol / g, about 90 μmol / g, about 95 μmol / g, about 100 μmol / g, about 105 μmol / g, about 110 μmol / g, about 115 μmol / g, about 120 μmol / g, or any range including and / or between any two of these values. In any embodiment disclosed herein, the Lewis acidity of the transition alumina may be from about 10 μmol / g to about 25 μmol / g.

[0038] In any embodiment disclosed herein, the transition alumina may include a strontium-containing phase. For example, in any embodiment disclosed herein, the strontium-containing phase may include SrAl2O4. In any embodiment, SrAl2O4 may be present in the transition alumina in an amount of about 1 wt% to about 16 wt% based on the total weight of the transition alumina. For example, in any embodiment disclosed herein, the amount of SrAl2O4 may be about 1 wt%, about 1.5 wt%, about 2 wt%, about 2.5 wt%, about 3 wt%, about 3.5 wt%, about 4 wt%, about 4.5 wt%, about 5 wt%, about 5.5 wt%, about 6 wt%, about 6.5 wt%, about 7 wt%, about 7.5 wt%, about 8 wt%, about 8.5 wt%, about 9 wt%, about 9.5 wt%, about 10 wt%, about 10.5 wt%, about 11 wt%, about 11.5 wt%, about 12 wt%, about 12.5 wt%, about 13 wt%, about 13.5 wt%, about 14 wt%, about 14.5 wt%, about 15 wt%, about 15.5 wt%, about 16 wt%, or any range including and / or between any two of the foregoing values.

[0039] In any of the embodiments disclosed herein, the crystallite size of the transition alumina obtained from the method of the present technology may be about to about Suitable crystallite sizes may include, but are not limited to, about about about about about about about about about about about about about about about about about about about about about or any range including and / or intermediate between any two of these values. In any of the embodiments disclosed herein, the crystallite size may be about to about about to about about to about or any range including and / or intermediate between any two of these values.

[0040] The surface area of the transition alumina obtained by the method of the present technology may be about 120 m 2 / g to about 200 m 2 / g. For example, in any of the embodiments disclosed herein, the surface area may be about 120 m 2 / g, about 125 m 2 / g, about 130 m 2 / g, about 135 m 2 / g, about 140 m 2 / g, about 145 m 2 / g, about 150 m 2 / g, about 155 m 2 / g, about 160 m 2 / g, about 165 m 2 / g, about 170 m 2 / g, about 175 m 2 / g, about 180 m 2 / g, about 185 m 2 / g, about 190 m 2 / g, about 195 m 2 / g, about 200 m 2 / g, or any range including and / or intermediate between any two of these values. In any embodiment disclosed herein, the surface area of the transitional alumina may be about 120 m 2 / g to about 200 m 2 / g, about 150 m 2 / g to about 180 m 2 / g, or any range including and / or intermediate between any two of these values.

[0041] The transitional alumina formed according to the method disclosed herein in any embodiment may be strontium-doped boehmite. Additionally or alternatively, in some embodiments, the method of the present technology may further include removing strontium from the strontium-doped transitional alumina. For example, in any embodiment disclosed herein, removing strontium from the strontium-doped transitional alumina may include combining the strontium-doped transitional alumina with water and acetic acid to obtain a reaction mixture; heating the reaction mixture to a temperature and for a period of time that converts the strontium-doped transitional alumina to undoped transitional alumina; removing the undoped transitional alumina from the reaction mixture; washing the undoped transitional alumina with water; and drying the undoped transitional alumina.

[0042] As disclosed herein in any embodiment, the transitional alumina may be undoped transitional alumina. Thus, in any embodiment disclosed herein, the method may further include doping boehmite with one or more of a rare earth element, tin or its oxide, bismuth or its oxide, an alkaline earth element, or a mixture of two or more thereof. Suitable rare earth elements may include yttrium, scandium, praseodymium, neodymium, promethium, samarium, europium, terbium, dysprosium, holmium, erbium, thulium, lutetium, ytterbium, gadolinium, cerium, lanthanum, or a mixture of any two or more thereof. Suitable alkaline earth elements may be selected from magnesium, calcium, strontium, or barium.

[0043] In a related aspect, the present technology provides a transitional alumina comprising SrAl2O4. In any of the embodiments disclosed herein, the transitional alumina may comprise SrAl2O4 in an amount of about 1 wt% to about 16 wt% based on the total weight of the transitional alumina. For example, in any of the embodiments disclosed herein, the amount of SrAl2O4 may be about 1 wt%, about 1.5 wt%, about 2 wt%, about 2.5 wt%, about 3 wt%, about 3.5 wt%, about 4 wt%, about 4.5 wt%, about 5 wt%, about 5.5 wt%, about 6 wt%, about 6.5 wt%, about 7 wt%, about 7.5 wt%, about 8 wt%, about 8.5 wt%, about 9 wt%, about 9.5 wt%, about 10 wt%, about 10.5 wt%, about 11 wt%, about 11.5 wt%, about 12 wt%, about 12.5 wt%, about 13 wt%, about 13.5 wt%, about 14 wt%, about 14.5 wt%, about 15 wt%, about 15.5 wt%, about 16 wt%, or any range including and / or between any two of the foregoing values.

[0044] In any of the embodiments disclosed herein, the transitional alumina may include, but is not limited to, γ-Al2O3, η-Al2O3, δ-Al2O3, θ-Al2O3, κ-Al2O3, χ-Al2O3, or a combination of two or more thereof. In any of the embodiments disclosed herein, the transitional alumina may include γ-alumina, χ-alumina, or a mixture thereof. In any of the embodiments disclosed herein, the transitional alumina may include γ-alumina.

[0045] The transition alumina obtained according to the methods disclosed herein may have a reduced number of Lewis acid sites. In any of the embodiments disclosed herein, the Lewis acidity of the transition alumina may be less than or equal to about 120 μmol / g. For example, in any of the embodiments disclosed herein, the Lewis acidity of the transition alumina may be from about 120 μmol / g to about 10 μmol / g. In any of the embodiments disclosed herein, the Lewis acidity of the transition alumina may be about 10 μmol / g, about 11 μmol / g, about 12 μmol / g, about 13 μmol / g, about 14 μmol / g, about 15 μmol / g, about 16 μmol / g, about 17 μmol / g, about 18 μmol / g, about 19 μmol / g, about 20 μmol / g, about 25 μmol / g, about 30 μmol / g, about 35 μmol / g, about 40 μmol / g, about 45 μmol / g, about 50 μmol / g, about 55 μmol / g, about 60 μmol / g, about 65 μmol / g, about 70 μmol / g, about 80 μmol / g, about 85 μmol / g, about 90 μmol / g, about 95 μmol / g, about 100 μmol / g, about 105 μmol / g, about 110 μmol / g, about 115 μmol / g, about 120 μmol / g, or any range including and / or between any two of these values. In any of the embodiments disclosed herein, the Lewis acidity of the transition alumina may be from about 10 μmol / g to about 25 μmol / g.

[0046] In any of the embodiments disclosed herein, the average crystallite size of the transition alumina obtained from the methods of the present technology may be about to about Suitable crystallite sizes may include, but are not limited to, about about about about about about about about about about about about about about about about about about about about about or any range including and / or between any two of these values. In any of the embodiments disclosed herein, the crystallite size may be about to about about to about about to about or any range including and / or between any two of these values. In any of the embodiments described herein, the average crystallite size refers to the crystallite size measured at the 120 reflection of boehmite using X-ray diffraction and having a width analyzed according to the Scherrer equation.

[0047] The surface area of the transition alumina can be about 120 m 2 / g to about 200 m 2 / g. For example, in any of the embodiments disclosed herein, the surface area can be about 120 m 2 / g, about 125 m 2 / g, about 130 m 2 / g, about 135 m 2 / g, about 140 m 2 / g, about 145 m 2 / g, about 150 m 2 / g, about 155 m 2 / g, about 160 m 2 / g, about 165 m 2 / g, about 170 m 2 / g, about 175 m 2 / g, about 180 m 2 / g, about 185 m 2 / g, about 190 m 2 / g, about 195 m 2 / g, about 200 m 2 / g, or any range including and / or between any two of these values. In any of the embodiments disclosed herein, the surface area of the transition alumina can be about 120 m 2 / g to about 200 m 2 / g, about 150 m 2 / g to about 180 m 2 / g, or any range including and / or between any two of these values.

[0048] In another related aspect, the present technology provides a composition comprising boehmite prepared according to the strontium-catalyzed method described herein in any embodiment, transition alumina prepared according to the method described herein in any embodiment, or transition alumina as described herein in any embodiment. As described herein in any embodiment, the composition may optionally be a fluid catalytic cracking (FCC) catalyst, Y-zeolite, FCC additive, emission control material, cobalt catalyst support, steam reforming catalyst, emission control catalyst, hydrocracking catalyst, hydrotreating catalyst, and a catalyst support for various chemical process conversion catalysts. Additionally or alternatively, in some embodiments, the composition may be a catalyst comprising a mixture of Y-zeolite and boehmite or transition alumina as described and / or prepared according to any embodiment disclosed herein.

[0049] In any embodiment disclosed herein, the composition may comprise transition alumina, which comprises SrAl2O4. For example, in any embodiment disclosed herein, the transition alumina may comprise SrAl2O4 in an amount of from about 1 wt% to about 16 wt% based on the total weight of the transition alumina. For example, in any embodiment disclosed herein, the amount of SrAl2O4 may be about 1 wt%, about 1.5 wt%, about 2 wt%, about 2.5 wt%, about 3 wt%, about 3.5 wt%, about 4 wt%, about 4.5 wt%, about 5 wt%, about 5.5 wt%, about 6 wt%, about 6.5 wt%, about 7 wt%, about 7.5 wt%, about 8 wt%, about 8.5 wt%, about 9 wt%, about 9.5 wt%, about 10 wt%, about 10.5 wt%, about 11 wt%, about 11.5 wt%, about 12 wt%, about 12.5 wt%, about 13 wt%, about 13.5 wt%, about 14 wt%, about 14.5 wt%, about 15 wt%, about 15.5 wt%, about 16 wt%, or include and / or be any range between any two of the foregoing values.

[0050] In any embodiment disclosed herein, the transition alumina may include, but is not limited to, γ-Al2O3, η-Al2O3, δ-Al2O3, θ-Al2O3, κ-Al2O3, χ-Al2O3, or a combination of two or more thereof. In any embodiment disclosed herein, the transition alumina may include γ-alumina, χ-alumina, or a mixture thereof. In any embodiment disclosed herein, the transition alumina may include γ-alumina.

[0051] The transition alumina obtained according to the method disclosed herein may have a reduced number of Lewis acid sites. In any of the embodiments disclosed herein, the Lewis acidity of the transition alumina may be less than or equal to about 120 μmol / g. For example, in any of the embodiments disclosed herein, the Lewis acidity of the transition alumina may be from about 120 μmol / g to about 10 μmol / g. In any of the embodiments disclosed herein, the Lewis acidity of the transition alumina may be about 10 μmol / g, about 11 μmol / g, about 12 μmol / g, about 13 μmol / g, about 14 μmol / g, about 15 μmol / g, about 16 μmol / g, about 17 μmol / g, about 18 μmol / g, about 19 μmol / g, about 20 μmol / g, about 25 μmol / g, about 30 μmol / g, about 35 μmol / g, about 40 μmol / g, about 45 μmol / g, about 50 μmol / g, about 55 μmol / g, about 60 μmol / g, about 65 μmol / g, about 70 μmol / g, about 80 μmol / g, about 85 μmol / g, about 90 μmol / g, about 95 μmol / g, about 100 μmol / g, about 105 μmol / g, about 110 μmol / g, about 115 μmol / g, about 120 μmol / g, or any range including and / or between any two of these values. In any of the embodiments disclosed herein, the Lewis acidity of the transition alumina may be from about 10 μmol / g to about 25 μmol / g.

[0052] In any of the embodiments disclosed herein, the crystallite size of the transition alumina obtained from the method of the present technology may be about to about Suitable crystallite sizes may include but are not limited to about about about about about about about about about about about about about about about about about about about about about or any range including and / or between any two of these values. In any of the embodiments disclosed herein, the crystallite size may be about to about about to about about to about or any range including and / or between any two of these values.

[0053] The surface area of the transitional alumina can be about 120 m 2 / g to about 200 m 2 / g. For example, in any of the embodiments disclosed herein, the surface area can be about 120 m 2 / g, about 125 m 2 / g, about 130 m 2 / g, about 135 m 2 / g, about 140 m 2 / g, about 145 m 2 / g, about 150 m 2 / g, about 155 m 2 / g, about 160 m 2 / g, about 165 m 2 / g, about 170 m 2 / g, about 175 m 2 / g, about 180 m 2 / g, about 185 m 2 / g, about 190 m 2 / g, about 195 m 2 / g, about 200 m 2 / g, or any range including and / or between any two of these values. In any of the embodiments disclosed herein, the surface area of the transitional alumina can be about 120 m 2 / g to about 200 m 2 / g, about 150 m 2 / g to about 180 m 2 / g, or any range including and / or between any two of these values.

[0054] The invention as generally described above will be more readily understood by reference to the following examples, which are provided by way of illustration and are not intended to limit the invention.

[0055] Examples

[0056] Example 1: Preparation of undoped boehmite (or AlOOH) and γ-alumina via a strontium-catalyzed method. A strontium salt (such as strontium acetate or strontium nitrate) is dissolved in water at room temperature. The solution is then heated to 50 °C, and fast-calcined gibbsite (FCG) is added to obtain a slurry. The slurry is heated to 90 °C, at which point sufficient Na2CO3 is added to raise the pH to 9, and then the slurry is heated to 99 °C.

[0057] The formation of SrCO3 occurs rapidly and is completed within about one hour. A strontium content of 4 wt% is measured as SrO equivalent. At 24 hours, approximately 50% of the FCG is converted to AlOOH, and after about one week, the FCG is completely converted to AlOOH at 99 °C.

[0058] As described above, the resulting AlOOH (boehmite) is additionally treated with acetic acid to remove strontium, allowing strontium to be recycled as strontium acetate. Here, a material sample (about 20 g) is suspended in about 200 g of deionized water, and dilute acetic acid (0.9 g diluted with 50 g of water) is added dropwise. After the addition of dilute acetic acid, the reaction mixture is heated to 80 °C, held for two hours with stirring, and then hot filtered. The filtrate is washed with 100 g of hot deionized water and dried at about 110 °C. The steam content during drying is minimal. Analysis of the combined filtrates demonstrates quantitative strontium removal. The XRD pattern of the treated solid ( Figure 1 ) reveals boehmite (with trace amounts of the Al(OH)3 phase initially present. Diffraction analysis confirms that the material was initially a mixture of strontianite, AlOOH, and trace amounts of the Al(OH)3 phase ( Figure 1 ). The AlOOH microcrystal size (along 120) is the same before and after strontium removal within the experimental error. Under our experimental conditions, AlOOH does not change. The amorphous, untransformed alumina nutrient also does not change detectably.

[0059] When calcined at 600 °C, AlOOH transforms to γ-Al2O3. χ-Al2O3 is not detected by X-ray diffraction (XRD). As Figure 2 shown, SrCO3 remains stable during calcination. In particular, the XRD pattern of the resulting transition alumina shows that SrCO3 does not decompose after calcination at 600 °C. When calcined at 800 °C, the SrCO3 present in the boehmite decomposes, and SrAl2O4 is formed in addition to the transition alumina. When calcined at 600 °C, the diffraction intensity pattern in the range of about 30 - 40° 2θ is consistent with that of relatively large crystals of γ-Al2O3. Without being bound by theory, it is believed that such large crystals appear because the parent boehmite of the resulting transition alumina is relatively large, where the microcrystal size along 120 is about In fact, strontium is associated with faster microcrystal size growth kinetics compared to other systems. Perhaps this is associated with the lower level of strong Lewis acidity observed in Sr-doped alumina.

[0060] As described above, the resulting transition alumina is additionally treated with acetic acid to remove strontium, leaving γ-Al2O3 as the only solid phase detectable by XRD. Analysis of the combined filtrates demonstrates quantitative strontium removal ( Figure 2)。Prior to the removal of SrCO3, the surface area of the mixture was 160 m 2 / g. After the removal of SrCO3, the surface area increased to 171 m 2 / g. The SrCO3 associated with the narrow diffraction lines is the dense, low surface area component of the composite. Its removal results in an increase in the surface area of the residue.

[0061] As demonstrated above, the inventors have found that strontium acetate catalyzes the direct hydration of FCG to boehmite at pH 9 without the formation of bayerite. A mixture of AlOOH and SrCO3 is formed. The SrCO3 in the resulting boehmite can be dissolved using acetic acid to recover water-soluble strontium acetate. This strontium acetate can be used for subsequent FCG hydration to produce more AlOOH and SrCO3 with sodium carbonate at pH 9. The process acts catalytically in strontium acetate. At 24 hours, compared to lanthanum and bismuth (about ), more AlOOH crystallizes in the presence of strontium ( diameter). This results in larger crystals of γ-Al2O3.

[0062] Example 2: Undoped boehmite was prepared via a strontium-catalyzed method and a comparative lanthanum-catalyzed method (Comparative Example A).

[0063] Boehmite crystallization was as follows: A lanthanum or strontium solution was prepared and heated to 50 °C. FCG was added at 50 °C to make a ~20% solid mixture, and the slurry was heated to 90 °C. At 90 °C, sodium carbonate was added in an experiment where AlOOH grows at pH 9. The slurry was heated to 99 °C; when T = 99 °C, the reaction was considered to start, and AlOOH crystallization was carried out.

[0064] Three XRD reflections, 020, 120, and 031, were used to evaluate AlOOH crystallization run at pH 5.5 and 9 in the presence of lanthanum nitrate and at pH 9 in the presence of strontium acetate / sodium carbonate. For La- and Sr-doped AlOOH crystallization at pH 9, the intensity became constant after about 168 hours. At pH 9, between 96 and 168 hours, complete conversion to AlOOH occurred. Using these results, the fraction converted to AlOOH was at Figure 3 (for lanthanum; Comparative Example A) and Figure 4(For strontium) is shown. The rate of AlOOH formation at pH 9 in the presence of lanthanum salts and strontium salts is similar. While not bound by theory, it is believed that most of the ionic strength is due to the sodium salt mixture under these conditions. At pH 9, the conversion to AlOOH is 10 - 15% after 1 hour and approximately 50% after 24 hours. For the lanthanum-catalyzed method, at pH 5.5, the conversion to AlOOH is approximately 8% after 1 hour, approximately 25% after 24 hours, and is still incomplete after 11 days, and the remainder of the material is substantially amorphous activated alumina.

[0065] Using the Liftshitz, Slyov, and Wagner (LSW) model, the microcrystalline size growth rate of lanthanum- and strontium-catalyzed boehmite formation was evaluated. The LSW model:

[0066] D t -D o =k(t - t o ) 1 / n , where D t and D o are the particle sizes at time t and time = 0, k is the rate constant, and n is a parameter between 2 and 4 that describes the nature of the ripening process. When n = 2, the diffusion of ions at the solution / particle boundary is rate-limiting. For n = 3, the diffusion of ions through the solution controls the rate, while for n = 4, the dissolution rate of less reactive or smaller particles controls the rate. Since AlOOH is initially present at t o = 0, the LSW model simplifies the equation to D t -D0 = kt 1 / n . For all cases analyzing AlOOH growth at pH 9, the initial AlOOH crystal size (along the 120 direction) is approximately As shown in Table 1, the rate constant for the growth of AlOOH microcrystal size with Sr is 60% greater than that with La.

[0067] Table 1: LSW model regression parameters for the growth of AlOOH microcrystal size for strontium- and lanthanum-catalyzed methods.

[0068]

[0069] Paragraph A. A strontium-catalyzed method for preparing boehmite, the method comprising: combining a strontium material, rapidly calcined boehmite trihydrate, and water to obtain an aqueous suspension; contacting the aqueous suspension with a water-soluble carbonate material; and heating the aqueous suspension to a temperature sufficient to form at least about 5 wt% boehmite based on the total weight of the solids and for a period of time.

[0070] Paragraph B. The method according to Paragraph A, wherein the strontium material comprises strontium acetate, strontium nitrate, strontium chloride, strontium bromide, strontium iodide, or a mixture of any two or more thereof.

[0071] Paragraph C. The method according to Paragraph A or B, wherein the strontium material comprises strontium acetate.

[0072] Paragraph D. The method according to any one of Paragraphs A to C, wherein the strontium material is present in an amount lower than the saturation point of the strontium material in an aqueous solution.

[0073] Paragraph E. The method according to any one of Paragraphs A to D, wherein the aqueous suspension comprises from about 1 wt% to about 40 wt% solids.

[0074] Paragraph F. The method according to any one of Paragraphs A to E, wherein the aqueous suspension comprises from about 10 wt% to about 30 wt% solids.

[0075] Paragraph G. The method according to any one of Paragraphs A to F, wherein the aqueous suspension comprises from about 15 wt% to about 25 wt% solids.

[0076] Paragraph H. The method according to any one of Paragraphs A to G, wherein the method further comprises heating the aqueous suspension to a temperature of about 30 °C to about 110 °C before contacting the aqueous suspension with the water-soluble carbonate material.

[0077] Paragraph I. The method according to Paragraph H, wherein the temperature is about 45 °C to about 100 °C.

[0078] Paragraph J. The method according to any one of Paragraphs A to I, wherein the pH of the aqueous solution is about 7 to about 10.

[0079] Paragraph K. The method according to any one of Paragraphs A to J, wherein the pH of the aqueous suspension is about 8 to about 10.

[0080] Paragraph L. The method according to any one of Paragraphs A to K, wherein the pH of the aqueous suspension is about 9.

[0081] Paragraph M. The method according to any one of Paragraphs A to L, wherein at least about 10 wt% to 100 wt% of boehmite is formed based on the total weight of the solids.

[0082] Paragraph N. The method according to any one of Paragraphs A to M, wherein the method has a faster microcrystal size growth rate compared to a non-strontium-catalyzed boehmite formation method.

[0083] Paragraph O. The method according to any one of Paragraphs A to N, wherein the microcrystal size of the boehmite is about to about

[0084] Paragraph P. The method according to paragraph O, wherein the crystallite size is about to about

[0085] Paragraph Q. The method according to any one of paragraphs A to P, wherein the boehmite contains strontium carbonate.

[0086] Paragraph R. The method according to any one of paragraphs A to Q, wherein the method further comprises removing strontium from the boehmite.

[0087] Paragraph S. The method according to paragraph R, wherein removing strontium carbonate from the boehmite comprises: combining the boehmite with water and acetic acid to obtain a reaction mixture; heating the reaction mixture to a temperature sufficient to convert the strontium carbonate to strontium acetate for a period of time; removing the boehmite from the reaction mixture; washing the boehmite with water; and drying the boehmite.

[0088] Paragraph T. The method according to any one of paragraphs A to P, wherein the boehmite is undoped boehmite.

[0089] Paragraph U. The method according to paragraph T, wherein the method further comprises doping the undoped boehmite with one or more of rare earth elements, bismuth, alkaline earth metals or mixtures thereof.

[0090] Paragraph V. A boehmite prepared by the method according to any one of paragraphs A to U.

[0091] Paragraph W. A method for preparing transition alumina, the method comprising: (i) preparing boehmite via a strontium-catalyzed method, wherein the strontium-catalyzed method of step (i) comprises: combining a strontium material, rapidly calcined gibbsite and water to obtain an aqueous suspension; contacting the aqueous suspension with a caustic material; and heating the aqueous suspension to a temperature sufficient to form at least about 5 wt% boehmite based on the total weight of the solids for a period of time; and (ii) calcining the boehmite to form transition alumina.

[0092] Paragraph X. The method according to paragraph W, wherein the boehmite is obtained via a strontium-catalyzed method according to any one of paragraphs A to U.

[0093] Paragraph Y. The method according to paragraph W or X, wherein the calcination is carried out at a temperature of about 500 °C to about 1000 °C.

[0094] Paragraph Z. The method according to any one of paragraphs W to Y, wherein the calcination temperature is from about 550 °C to about 750 °C.

[0095] Paragraph AA. The method according to paragraph Z, wherein the calcination temperature is from about 550 °C to about 650 °C.

[0096] Paragraph AB. The method according to any one of paragraphs W to Y, wherein the calcination temperature is from about 750 °C to about 900 °C.

[0097] Paragraph AC. The method according to paragraph AB, wherein the calcination temperature is from about 750 °C to about 850 °C.

[0098] Paragraph AD. The method according to any one of paragraphs W to AC, wherein the transitional alumina comprises γ-alumina, χ-alumina or a mixture thereof.

[0099] Paragraph AE. The method according to any one of paragraphs W to AD, wherein the transitional alumina is γ-alumina.

[0100] Paragraph AF. The method according to any one of paragraphs W to AE, wherein the Lewis acidity of the transitional alumina is less than or equal to about 120 μmol / g.

[0101] Paragraph AG. The method according to paragraph AF, wherein the Lewis acidity of the transitional alumina is from about 120 μmol / g to about 10 μmol / g.

[0102] Paragraph AH. The method according to paragraph AF, wherein the Lewis acidity of the transitional alumina is from about 25 μmol / g to about 10 μmol / g.

[0103] Paragraph AI. The method according to any one of paragraphs W to AH, wherein the transitional alumina comprises SrAl2O4.

[0104] Paragraph AJ. The method according to any one of paragraphs W to AI, wherein the crystallite size of the transitional alumina is about to about

[0105] Paragraph AK. The method according to paragraph AJ, wherein the crystallite size is about to about

[0106] Paragraph AL. The method according to any one of paragraphs W to AK, wherein the surface area of the transitional alumina is from about 120 m 2 / g to about 200 m 2 / g.

[0107] Paragraph AM. The method according to paragraph AL, wherein the surface area of the transitional alumina is about 150 m 2 / g to about 180 m 2 / g.

[0108] Paragraph AN. The method according to any one of paragraphs W to AM, wherein the transitional alumina is strontium-doped transitional alumina.

[0109] Paragraph AO. The method according to any one of paragraphs W to AN, wherein the method further comprises removing strontium from the transitional alumina.

[0110] Paragraph AP. The method according to paragraph AO, wherein the transitional alumina is undoped transitional alumina.

[0111] Paragraph AQ. The method according to paragraph AP, wherein the method further comprises doping the undoped transitional alumina with one or more of rare earth elements, bismuth, alkaline earth metals, or mixtures thereof.

[0112] Paragraph AR. A transitional alumina comprising SrAl2O4.

[0113] Paragraph AS. The transitional alumina according to paragraph AR, wherein the SrAl2O4 is present in an amount of about 1 wt% to about 16 wt%.

[0114] Paragraph AT. The transitional alumina according to paragraph AR or AS, further comprising γ-alumina, χ-alumina, or mixtures thereof.

[0115] Paragraph AU. The transitional alumina according to any one of paragraphs AR to AT, wherein the Lewis acidity of the transitional alumina is less than or equal to about 120 μmol / g.

[0116] Paragraph AV. The transitional alumina according to paragraph AU, wherein the Lewis acidity of the transitional alumina is about 25 μmol / g to about 10 μmol / g.

[0117] Paragraph AW. The transitional alumina according to any one of paragraphs AR to AV, wherein the crystallite size of the transitional alumina is about to about

[0118] Paragraph AX. The transitional alumina according to any one of paragraphs AR to AW, wherein the surface area of the transitional alumina is about 120 m 2 / g to about 200 m 2 / g.

[0119] Paragraph AY. A composition comprising boehmite prepared according to any one of paragraphs A to U, transition alumina prepared according to any one of paragraphs W to AQ, or transition alumina prepared according to any one of paragraphs AR to AX, wherein the composition is selected from fluid catalytic cracking (FCC) catalysts, Y-zeolites, FCC additives, emission control materials, cobalt catalyst supports, Y-zeolites, FCC additives, emission control materials, cobalt catalyst supports, steam reforming catalysts, emission control catalysts, hydrocracking catalysts, hydrotreating catalysts, and catalyst supports for various chemical process conversion catalysts.

[0120] Although certain embodiments have been illustrated and described, it should be understood that changes and modifications can be made in accordance with ordinary skill in the art without departing from the broader aspects of the technology of the invention as defined in the following claims.

[0121] The embodiments illustratively described herein can be practiced appropriately without any one or more elements, one or more limitations not specifically disclosed herein. Thus, for example, the terms "comprising," "including," "containing," etc. should be read broadly without limitation. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and the use of such terms and expressions is not intended to exclude any equivalents or portions of the features shown and described, but it should be recognized that various modifications can be made within the scope of the technology claimed. Additionally, the phrase "consisting essentially of" will be understood to include those elements specifically recited and those additional elements that do not materially affect the basic and novel features of the technology claimed. The phrase "consisting of" excludes any element not specified.

[0122] The present disclosure is not limited to the specific embodiments described in this application. Many modifications and variations of the technology of the invention are possible without departing from the spirit and scope of the technology of the invention, which will be apparent to those skilled in the art. In addition to those enumerated herein, functional equivalent methods and compositions within the scope of the present disclosure will be apparent to those skilled in the art from the foregoing description. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is limited only by the terms of the appended claims and the full scope of equivalents to which such claims are entitled. It should be understood that the present disclosure is not limited to the particular methods, reagents, compounds, or compositions that may, of course, vary. It should also be understood that the terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting.

[0123] In addition, where features or aspects of the present disclosure are described in terms of a Markush group, those skilled in the art will recognize that the present disclosure is also thereby described in terms of any individual member of the Markush group or subgroup of members.

[0124] As will be understood by those skilled in the art, for any and all purposes, particularly in terms of providing a written description, all ranges disclosed herein also cover any and all possible sub-ranges and combinations of sub-ranges thereof. Any listed range can be readily identified as being sufficiently described and enabling the same to be broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. By way of non-limiting example, each range discussed herein can be readily broken down into lower one-third, middle one-third, and upper one-third, etc. As will also be understood by those skilled in the art, all language such as "up to", "at least", "greater than", "less than", etc. includes the recited number and refers to ranges which can then be broken down into the sub-ranges as discussed above. Finally, as will be understood by those skilled in the art, a range includes each individual member therein.

[0125] All publications, patent applications, issued patents, and other documents mentioned in this specification are incorporated herein by reference as if each individual publication, patent application, issued patent, or other document was specifically and individually indicated to be incorporated by reference in its entirety. Definitions contained in text incorporated by reference are excluded to the extent they contradict definitions in the present disclosure.

[0126] Other embodiments are set forth in the following claims.

Claims

1. A strontium-catalyzed method for preparing boehmite, the method comprising: Combining a strontium material, rapidly calcined boehmite trihydrate, and water to obtain an aqueous suspension; Contacting the aqueous suspension with a water-soluble carbonate material; and Heating the aqueous suspension to a temperature sufficient to form at least 5 wt% boehmite based on the total weight of the solids and for a period of time, The method further comprising removing strontium from the boehmite.

2. The method according to claim 1, wherein the strontium material comprises strontium carboxylate, strontium nitrate, strontium chloride, strontium bromide, strontium iodide, or a mixture of any two or more thereof.

3. The method according to claim 2, wherein the strontium material comprises strontium acetate.

4. The method according to any one of claims 1 to 3, wherein the strontium material is present in an amount below the saturation point of the strontium material in an aqueous solution.

5. The method according to any one of claims 1 to 3, wherein the aqueous suspension comprises 1 wt% to 40 wt% solids.

6. The method according to claim 4, wherein the aqueous suspension comprises 1 wt% to 40 wt% solids.

7. The method according to any one of claims 1 to 3 and 6, wherein the method further comprises heating the aqueous suspension to a temperature of 30°C to 110°C before contacting the aqueous suspension with the water-soluble carbonate material.

8. The method according to claim 4, wherein the method further comprises heating the aqueous suspension to a temperature of 30°C to 110°C before contacting the aqueous suspension with the water-soluble carbonate material.

9. The method according to claim 5, wherein the method further comprises heating the aqueous suspension to a temperature of 30°C to 110°C before contacting the aqueous suspension with the water-soluble carbonate material.

10. The method according to any one of claims 1 to 3, 6, 8, and 9, wherein the pH of the aqueous solution is 7 to 10.

11. The method according to any one of claims 1 to 3, 6, 8, and 9, wherein 10 wt% to 100 wt% boehmite is formed based on the total weight of the solids.

12. The method according to any one of claims 1 to 3, 6, 8, and 9, wherein the method has a faster microcrystal size growth rate compared to a non-strontium-catalyzed boehmite formation method.

13. The method according to any one of claims 1 to 3, 6, 8 and 9, wherein the crystallite size of the boehmite is to 14. The method according to claim 10, wherein the crystallite size of the boehmite is to 15. A method for preparing transition alumina, the method comprising: (i) Preparing boehmite via a strontium-catalyzed method, wherein the strontium-catalyzed method of step (i) comprises: Combining a strontium material, rapidly calcined boehmite trihydrate, and water to obtain an aqueous suspension; Contacting the aqueous suspension with a caustic material; Heat the aqueous suspension to a temperature sufficient to form at least 5 wt% boehmite, based on the total weight of the solids, for a period of time; and Removing strontium from the boehmite; and (ii) Calcining the boehmite to form transition alumina.

16. The method according to claim 15, wherein the calcination is carried out at a temperature of 500°C to 1000°C.

17. The method according to claim 15, wherein the transition alumina comprises γ-alumina, χ-alumina, or a mixture thereof.

18. The method according to claim 16, wherein the transitional alumina comprises γ-alumina, χ-alumina or a mixture thereof.

19. The method according to any one of claims 15 to 18, wherein the Lewis acidity of the transitional alumina is less than or equal to 120 μmol / g.

20. The method according to claim 19, wherein the Lewis acidity of the transitional alumina is from 120 μmol / g to 10 μmol / g.

21. The method according to any one of claims 15 to 18 and 20, wherein the crystallite size of the transition alumina is to 22. The method according to claim 19, wherein the crystallite size of the transitional alumina is to

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