Aluminum oxide strip-shaped carrier and preparation method thereof

Abstract

The invention provides an aluminum oxide strip-shaped carrier and a preparation method thereof, and the preparation method comprises the following steps: (1) carrying out hydrothermal aging on slurry obtained by hydrolyzing alkoxy aluminum, and drying the obtained aged slurry to obtain a precursor; (2) carrying out first roasting on the precursor at 250-300 DEG C to obtain a pretreated precursor; and (3) mixing the pretreated precursor with pseudo-boehmite, an auxiliary agent, acid and water, molding, and then carrying out second roasting to obtain the aluminum oxide strip-shaped carrier. The preparation method comprises the following steps: performing primary roasting on a precursor obtained on the basis of slurry obtained by hydrolyzing alkoxy aluminum at a relatively low temperature of 250-300 DEG C, and then performing mixed molding and secondary roasting on the precursor, pseudo-boehmite, a molding aid, acid and the like; and finally, the high-performance aluminum oxide strip-shaped carrier with high specific surface area, large pore volume and large most probable pore diameter is prepared.

Description

Technical Field

[0001] This invention relates to the field of alumina technology, specifically to an alumina strip carrier and its preparation method. Background Technology

[0002] Alumina, as a catalyst support, offers numerous loading sites for active centers if it possesses a high specific surface area. Furthermore, its large pore volume and diameter facilitate rapid diffusion of reactant and product molecules, improving the utilization rate of active sites and inhibiting surface coking. Clearly, alumina strip supports that combine high specific surface area and large pore size can fulfill all these advantages when used as supports for fixed-bed catalysts, and can promote advancements in catalyst technology in fields such as catalytic cracking, reforming, and hydrogenation.

[0003] Alumina strip supports are generally prepared from alumina precursors through a series of molding methods. Therefore, the properties of the precursors and the molding process determine the properties of the supports. However, in a series of studies, it has been found that the specific surface area and pore volume of the precursors and supports are often negatively correlated, making it difficult to achieve large values ​​simultaneously.

[0004] CN201810881116.9 proposes a method for preparing macroporous alumina strip supports with a dual-pore-size distribution, wherein the alumina strip supports have a large pore volume (0.6-0.75 cm³). 3 .g -1 It exhibits a bimodal pore size distribution (40-55 nm and 50-200 nm). The most probable pore diameters are 40-55 nm and 0.5-2 μm, respectively. However, its specific surface area is only 40-60 m². 2 .g -1 It did not meet the requirements of many moving bed catalysts, nor did it change the negative correlation between the specific surface area and pore volume of the support.

[0005] CN201410723839.8 proposes a method for preparing a high specific surface area alumina carrier, comprising the following steps: (1) impregnating hydrated alumina precipitate with an aqueous solution containing carbonaceous organic compounds by volume; (2) filtering and drying the hydrated alumina precipitate after impregnation with the aqueous solution containing carbonaceous organic compounds in step (1); (3) using boehmite obtained in step (2) as raw material, molding and drying it, and then unsaturatedly spraying it with a mixed solution of phosphoric acid and ammonium oxalate. The impregnated carrier is then subjected to sealed heating treatment, and the treated carrier is dried and calcined to obtain the alumina carrier. The alumina carrier prepared by this method has a high specific surface area (>230 m²). 2 .g -1 ) and larger (>0.8cm) 3 .g -1The pore volume is large, and the macropores are unevenly distributed radially on the carrier. However, this method is cumbersome, and adding too many kinds of additives and pore expanders can easily reduce the purity of the carrier. Frequent washing processes can also easily cause a large loss of material.

[0006] Finding a simple process to prepare alumina supports with high specific surface area, large pore volume, and large most probable pore size is a pressing technical problem that needs to be solved. Summary of the Invention

[0007] To address the above problems, this invention provides an alumina strip carrier and its preparation method.

[0008] On one hand, the present invention provides a method for preparing an alumina strip carrier, comprising the following steps:

[0009] (1) Hydrothermal aging of the slurry after hydrolysis of aluminum alkoxy, and drying of the aged slurry to obtain the precursor;

[0010] (2) The precursor is first calcined at 250-300°C to obtain a pretreated precursor;

[0011] (3) The pretreated precursor is mixed with boehmite, additives, acid and water, shaped and then subjected to a second calcination to obtain the alumina strip carrier.

[0012] Optionally, the first roasting in step (2) is carried out for 4 to 8 hours.

[0013] Optionally, the specific surface area of ​​the pseudoboehmite in step (3) is 250–330 m². 2 .g -1 Preferably, it is 280–320m 2 .g -1 The pore volume is 0.35–1 cm³. 3 .g -1 The preferred size is 0.35–0.7 cm. 3 .g -1 The most probable pore size is 4–40 nm, preferably 4–20 nm.

[0014] Optionally, the mixing mass ratio of the pretreated precursor to the pseudoboehmite in step (3) is 1:1 to 3.

[0015] Optionally, in step (3),

[0016] Based on the total mass of the pretreated precursor and the pseudoboehmite, the mass percentage of the additive is 1-3%, the mass percentage of the acid is 10-20%, and the mass percentage of water is 50-80%.

[0017] Optionally, in step (3),

[0018] The adjuvant is guar gum powder;

[0019] The acid is selected from one or more of formic acid, acetic acid, citric acid, malonic acid, nitric acid, and hydrochloric acid.

[0020] Optionally, in step (3), the second calcination is carried out at 500-600°C for 5-10 hours.

[0021] Optionally, the aluminum alkoxy in step (1) is selected from C4 to C6 aluminum alkoxy, preferably from one or more of aluminum butoxy, aluminum pentoxy, and aluminum hexoxy.

[0022] Optionally, the preparation method of the slurry after hydrolysis of alkoxyaluminum in step (1) includes the following steps:

[0023] (S1) The reaction between metallic aluminum and fatty alcohol is initiated by heating to a first temperature, and then the reaction is carried out at a second temperature to obtain the first intermediate material;

[0024] (S2) Add a first portion of water to the first intermediate material and perform pre-hydrolysis at the hydrolysis temperature. During the pre-hydrolysis process, add an aqueous solution of ammonium bicarbonate. After the pre-hydrolysis is completed, the second intermediate material is obtained.

[0025] (S3) Add a second portion of water to the second intermediate material. After no gas is generated, separate the organic phase and separate the supernatant to obtain the slurry after hydrolysis of the alkoxyaluminum.

[0026] On the other hand, the present invention also provides an alumina strip carrier, which is prepared according to the above preparation method;

[0027] The specific surface area of ​​the alumina strip carrier is ≥220.0 m². 2 .g -1 Hole volume ≥ 0.65 cm³ 3 .g -1 The most probable pore size is ≥9.0nm.

[0028] Beneficial effects:

[0029] In the preparation method of the alumina strip carrier of the present invention, based on the precursor obtained from the slurry after hydrolysis of alkoxyaluminum, a first calcination is carried out at a relatively low temperature of 250-300°C, and then mixed with boehmite, molding aid and acid, etc. for molding and a second calcination, so as to finally obtain a high-performance alumina strip carrier with high specific surface area, large pore volume and large most probable pore size. Detailed Implementation

[0030] The present application will be further described in detail below through embodiments. Through these descriptions, the features and advantages of the present application will become clearer and more apparent.

[0031] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0032] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0033] On one hand, the present invention provides a method for preparing an alumina strip carrier, comprising the following steps:

[0034] (1) Hydrothermal aging of the slurry after hydrolysis of aluminum alkoxy, and drying of the aged slurry to obtain the precursor;

[0035] (2) The precursor is first calcined at 250-300°C to obtain a pretreated precursor;

[0036] (3) The pretreated precursor is mixed with boehmite, additives, acid and water, shaped and then subjected to a second calcination to obtain the alumina strip carrier.

[0037] It should be noted that after molding in step (3), the mixture can be left to stand at room temperature for 1-3 hours, dried at 100-150℃ for 10-15 hours, and then subjected to a second calcination. Through years of research and experimentation, the inventors of this application unexpectedly discovered that the precursor of the alkoxyaluminum hydrolysis slurry, after hydrothermal aging and drying, undergoes a first calcination at a relatively low temperature of 250-300℃, followed by molding and a second calcination in step (3). The resulting alumina strip-shaped support possesses high specific surface area, large pore volume, and large most probable pore size. The specific surface area, pore volume, and most probable pore size of the alumina strip-shaped support reach or even exceed those of conventional alumina powder. Excellent supports can be prepared through a simple process, and the activity of catalysts loaded with such supports will be significantly enhanced. The specific calcination temperature can be 260℃, 265℃, 270℃, 275℃, 280℃, 285℃, 290℃, 295℃, etc.

[0038] In one embodiment of the preparation method described above, the first calcination in step (2) is carried out for 4 to 8 hours. The specific time for the first calcination can be 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, etc.

[0039] It should be noted that in the preparation method of the present invention, while controlling the temperature of the first calcination as described above in step (2), the time of the first calcination is controlled to be 4 to 8 hours, which can further improve the specific surface area, pore volume and most probable pore size of the prepared alumina strip carrier.

[0040] In another embodiment of the preparation method described above, the specific surface area of ​​the pseudoboehmite in step (3) is 250–330 m². 2 .g -1 Preferably, it is 280–320m 2 .g -1 The pore volume is 0.35–1 cm³. 3 .g -1 The preferred size is 0.35–0.7 cm. 3 .g -1 The most probable pore size is 4–40 nm, preferably 4–20 nm.

[0041] Specifically, the specific surface area of ​​the aforementioned pseudoboehmite can be 260 m². 2 .g -1 270m 2 .g -1 290m 2 .g -1 300m 2 .g -1 310m 2 .g -1 The pore volume can be 0.4 cm³. 3 .g -1 0.5cm 3 .g -1 0.6cm 3 .g -1 0.8cm 3 .g -1 0.9cm 3 .g -1 The most probable pore size can be 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm, 15nm, 16nm, 18nm, 25nm, 30nm, or 35nm. In the preparation method of the present invention, while controlling the temperature and time of the first calcination as described above in step (2), selecting pseudoboehmite with the above specific surface area, pore volume, and most probable pore size in step (3) is beneficial for preparing alumina strip carriers that simultaneously possess high specific surface area, large pore volume, and large most probable pore size.

[0042] In one embodiment of the preparation method of the present invention, the mixing mass ratio of the pretreated precursor and the pseudoboehmite in step (3) is 1:1 to 3.

[0043] The inventors of this application have discovered that not all pretreated precursors and boehmite mixed in arbitrary mass ratios can yield high-performance alumina strip supports. Only by controlling the mixing mass ratio of the pretreated precursors and boehmite as described above can alumina strip supports with high specific surface area, large pore volume, and large most probable pore size be prepared, thereby significantly improving the activity of related catalysts.

[0044] In one embodiment of the preparation method described above, in step (3),

[0045] Based on the total mass of the pretreated precursor and the pseudoboehmite, the mass percentage of the additive is 1-3%, the mass percentage of the acid is 10-20%, and the mass percentage of water is 50-80%.

[0046] As a variation of the implementation, the water content can be 50% to 100%. By controlling the proportions of additives, acid, and water as described above, the pretreated precursor and pseudoboehmite can be better molded to obtain a carrier with excellent performance.

[0047] In one embodiment of the preparation method described above, in step (3),

[0048] The adjuvant is guar gum powder;

[0049] The acid is selected from one or more of formic acid, acetic acid, citric acid, malonic acid, nitric acid, and hydrochloric acid.

[0050] It should be noted that after the pretreatment in step (3), the precursor, along with the pseudoboehmite, additives, acid, and water, can be thoroughly stirred to make the powder into a flocculent state, which can then be formed in an extruder. Guess powder, as a forming aid, can assist in better forming.

[0051] In another embodiment of the preparation method described above, the second calcination in step (3) is carried out at 500-600°C for 5-10 hours.

[0052] It should be noted that the preparation method of the present invention is a complete technical solution. In step (1), the slurry of alkoxyaluminum hydrolyzed is hydrothermally aged and then dried to obtain a precursor. In particular, in step (2), the precursor is first calcined at 250-300℃. Then, the molding in step (3) and the second calcination at 500-600℃ for 5-10 hours are carried out. In this way, an alumina strip support with high specific surface area, large pore volume and large most probable pore size can be prepared to significantly improve the activity of the relevant catalyst.

[0053] In one embodiment of the preparation method described above in this invention, the aluminum alkoxy in step (1) is selected from C4 to C6 aluminum alkoxy, preferably from one or more of aluminum butoxy, aluminum pentoxy, and aluminum hexoxy.

[0054] It should be noted that the use of C4-C6 alkoxyaluminum in step (1), followed by steps (2) and (3), is beneficial to improving the specific surface area, pore volume and most probable pore size of the prepared alumina strip carrier. The alkoxyaluminum used in the preparation method of the present invention is preferably self-made in the present invention.

[0055] In one embodiment of the preparation method of the present invention, the preparation method of the slurry after hydrolysis of alkoxyaluminum in step (1) includes the following steps:

[0056] (S1) The reaction between metallic aluminum and fatty alcohol is initiated by heating to a first temperature, and then the reaction is carried out at a second temperature to obtain the first intermediate material;

[0057] (S2) Add a first portion of water to the first intermediate material and perform pre-hydrolysis at the hydrolysis temperature. During the pre-hydrolysis process, add an aqueous solution of ammonium bicarbonate. After the pre-hydrolysis is completed, the second intermediate material is obtained.

[0058] (S3) Add a second portion of water to the second intermediate material. After no gas is generated, separate the organic phase and separate the supernatant to obtain the slurry after hydrolysis of the alkoxyaluminum.

[0059] It should be noted that the preparation method of the present invention first uses the alkoxyaluminum hydrolysis method to prepare an alumina precursor slurry. Specifically, alkoxyaluminum is first synthesized using metallic aluminum and fatty alcohol as raw materials, and then the obtained alkoxyaluminum is hydrolyzed to obtain a pseudoboehmite slurry. During or after complete hydrolysis, a certain amount of ammonium bicarbonate aqueous solution is added to the system. After complete hydrolysis, i.e., no gas is generated in the system, the organic phase in the system is separated and the supernatant is separated to obtain the above-mentioned alkoxyaluminum hydrolyzed slurry. As a preferred embodiment, the present invention first prepares the alkoxyaluminum hydrolyzed slurry through the above steps (S1) to (S3), and then prepares an alumina strip carrier with high specific surface area, large pore volume and large most probable pore size through the above steps (1) to (3).

[0060] It should be noted that in the above method for preparing the slurry after hydrolysis of alkoxyaluminum, in step (S1),

[0061] The aluminum metal is selected from one or more of aluminum blocks, aluminum briquettes, aluminum foil, aluminum shavings, and aluminum wire;

[0062] The fatty alcohol is selected from C4 to C6 fatty alcohols;

[0063] The molar ratio of the metallic aluminum to the fatty alcohol can be 1:(3.2-4.0), preferably 1:(3.6-4.0);

[0064] The first temperature can be 120–160°C, the second temperature can be 130–165°C, and the reaction time can be 30–90 min; and / or

[0065] In step (S2),

[0066] The mass ratio of the first portion of water to the metallic aluminum can be (10-15):1;

[0067] The hydrolysis temperature can be 80–100℃, and the pre-hydrolysis time can be 30–60 min;

[0068] The mass ratio of ammonium bicarbonate to water in the ammonium bicarbonate aqueous solution can be 1:(2.0-3.0);

[0069] Based on the amount of material fed, the molar ratio of metallic aluminum to ammonium bicarbonate in the ammonium bicarbonate aqueous solution in step (S1) is 1:(2.0-10.0); and / or

[0070] In step (S3),

[0071] The mass ratio of the second portion of water to the metallic aluminum can be (7-13):1; and / or

[0072] The slurry obtained after hydrolysis of alkoxyaluminum in step (S3) can be stirred at 400-600 rpm for 40-90 min, and then the above step (1) can be carried out. The hydrothermal aging in step (1) can be carried out at 90-120℃ for 6-12 h.

[0073] On the other hand, the present invention also provides an alumina strip-shaped carrier, which is prepared according to the above-described preparation method; the specific surface area of ​​the alumina strip-shaped carrier is ≥220.0 m². 2 .g -1 Hole volume ≥ 0.65 cm³ 3 .g -1 The most probable pore size is ≥9.0nm.

[0074] The alumina strip carrier of this invention simultaneously possesses high specific surface area, large pore volume, and large most probable pore size. Specifically, the specific surface area of ​​the alumina strip carrier can reach 220.0–250 m². 2 .g -1 The pore volume can reach 0.65–1.0 cm³. 3 .g -1The most probable pore size can reach 9.0–13 nm; the specific surface area, pore volume and most probable pore size of the alumina strip support reach or even exceed those of conventional alumina powder, which greatly improves the performance of the support. The catalytic activity of the catalyst obtained by loading the active component on such a support will be greatly improved.

[0075] The present invention will be further described in detail below through examples, but these examples are not intended to limit the invention. In the following examples, unless otherwise specified, the experimental instruments and raw materials involved are all commercially available products.

[0076] The specific surface area of ​​the pseudoboehmite used in the following examples or comparative examples is 297.15 m². 2 .g -1 The pore volume is 0.44 cm³. 3 .g -1 The most probable pore size is 5.8 nm.

[0077] Example 1

[0078] 9 g (0.33 mol) of aluminum shavings (99.996% by mass purity) and 151 mL (1.2 mol) of n-hexanol were added to a reaction vessel as reactants. The temperature was raised to 140 °C to initiate the reaction, and the temperature was controlled at 145 °C for 60 minutes to allow the aluminum shavings to react completely to form a n-hexanol solution of aluminum hexoxy (aluminum hexoxide). 100 mL of deionized water was added to pre-hydrolyze the aluminum hexoxy at 90 °C for 40 minutes. During the pre-hydrolysis, an ammonium bicarbonate solution prepared with 52.7 g of ammonium bicarbonate and 105.4 g of deionized water was added, with an aluminum to ammonium molar ratio of 1:2.0. After the pre-hydrolysis was completed, another 80 mL of deionized water was added until the aluminum alkoxy in the system was completely hydrolyzed. After no gas is generated in the system, the organic phase is separated from the system. The supernatant is separated using a separating funnel to obtain the lower slurry. The slurry is then stirred at 500 rpm for 60 min and placed in a hydrothermal aging reactor for aging at 120 °C for 12 h. The aged slurry is then dried at 120 °C for 12 h to obtain the corresponding precursor.

[0079] The aforementioned precursor was ground into powder and pretreated by calcining at 250℃ for 4 hours. Then, 25g of the pretreated precursor was mixed with 75g of boehmite to form a powder with a total mass of 100g. 2.3g of guar gum powder was added and mixed again. 4.71g of citric acid, 3.27g of 1:1 (V:V) nitric acid (ρ = 1.41g / mL), and 4.15g of acetic acid (total acid content: 11% of the total powder mass) were added separately. After mixing, 49g of water (total water content: 50% of the powder mass) was added, and the mixture was thoroughly stirred until the powder was in a flocculent state. The above material was extruded, allowed to stand at room temperature for 2 hours, dried at 120℃ for 12 hours, and then calcined at 550℃ for 6 hours to obtain the final alumina strip carrier. The specific surface area, pore volume, and most probable pore size of this carrier are shown in Table 1.

[0080] Example 2

[0081] The carrier was obtained according to the method of Example 1, except that 50g of the pretreated precursor was mixed with 50g of boehmite to form a powder with a total mass of 100g. The specific surface area, pore volume, and most probable pore size of the obtained carrier are shown in Table 1.

[0082] Example 3

[0083] The carrier was obtained according to the method of Example 1, except that 17g of 1:1 nitric acid was added (total acid added was 11% of the total mass of the powder), and 44g of water was added (total water added was 50% of the mass of the powder). The specific surface area, pore volume, and most probable pore size of the obtained carrier are shown in Table 1.

[0084] Example 4

[0085] The carrier product was obtained according to the method of Example 2, except that the pretreatment temperature was 300°C and the time was 6 hours. The specific surface area, pore volume and most probable pore size of the obtained carrier are shown in Table 1.

[0086] Comparative Example 1

[0087] The carrier product was obtained according to the method of Example 1, except that the strip carrier was prepared entirely from 100g of pseudoboehmite (i.e., the powder did not contain pretreated precursors). The specific surface area, pore volume, and most probable pore size of the carrier are shown in Table 1.

[0088] Comparative Example 2

[0089] The method of Example 1 is different in that no pretreatment is performed on the precursor. After mixing with acid and water, the mixture is too viscous to form flocculent material, and subsequent extrusion is not possible.

[0090] Comparative Example 3

[0091] To demonstrate the advantages of this support, a commonly used batch of solid-bed catalyst support was taken, calcined at 550℃ for 6 hours, and its specific surface area, pore volume and most probable pore diameter were analyzed. The results are shown in Table 1.

[0092] Comparative Example 4

[0093] To demonstrate the advantages of this support, a commonly used solid-bed catalyst support of a different batch than that in Comparative Example 3 was taken, calcined at 550℃ for 6 hours, and its specific surface area, pore volume and most probable pore diameter were analyzed. The results are shown in Table 1.

[0094] Table 1

[0095]

[0096] As can be seen from the parameters of the alumina strip support in Table 1, the above embodiments of the present invention pretreat the precursor at a lower temperature, and then form it with boehmite, molding aid, acid and water, followed by drying and calcination. The pretreated precursor can synergistically enhance the effect of boehmite, reducing the impact of the drying and calcination process on the specific surface area, pore volume and pore size of the entire system. Finally, an alumina strip support with high specific surface area, large pore volume and large most probable pore size is obtained. The specific surface area, pore volume and most probable pore size of the alumina strip support reach or even exceed those of conventional alumina powder, greatly improving the performance of the support. The catalytic activity of the catalyst obtained by loading the active component on such a support will be greatly improved.

[0097] The present application has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present application based on these embodiments, all of which fall within the protection scope of the present application.

Claims

1. A method for preparing an alumina strip carrier, characterized in that, Includes the following steps: (1) Hydrothermal aging of the slurry after hydrolysis of aluminum alkoxy, and drying of the aged slurry to obtain the precursor; (2) The precursor is first calcined at 250-300°C to obtain a pretreated precursor; (3) The pretreated precursor is mixed with boehmite, additives, acid and water, shaped and then subjected to a second calcination to obtain the alumina strip carrier.

2. The preparation method according to claim 1, characterized in that, In step (2), the first roasting is carried out for 4 to 8 hours.

3. The preparation method according to claim 1, characterized in that, The specific surface area of ​​the pseudoboehmite mentioned in step (3) is 250–330 m². 2 .g -1 Preferably, it is 280–320m 2 .g -1 The pore volume is 0.35–1 cm³. 3 .g -1 The preferred size is 0.35–0.7 cm. 3 .g -1 The most probable pore size is 4–40 nm, preferably 4–20 nm.

4. The preparation method according to claim 1, characterized in that, The mixing mass ratio of the pretreated precursor to the pseudoboehmite in step (3) is 1:1 to 3.

5. The preparation method according to claim 1, characterized in that, In step (3), Based on the total mass of the pretreated precursor and the pseudoboehmite, the mass percentage of the additive is 1-3%, the mass percentage of the acid is 10-20%, and the mass percentage of water is 50-80%.

6. The preparation method according to claim 1, characterized in that, In step (3), The adjuvant is guar gum powder; The acid is selected from one or more of formic acid, acetic acid, citric acid, malonic acid, nitric acid, and hydrochloric acid.

7. The preparation method according to claim 1, characterized in that, In step (3), the second calcination is carried out at 500-600℃ for 5-10 hours.

8. The preparation method according to claim 1, characterized in that, The aluminum alkoxy in step (1) is selected from C4 to C6 aluminum alkoxy, preferably from one or more of aluminum butoxy, aluminum pentoxy, and aluminum hexoxy.

9. The preparation method according to claim 1, characterized in that, The preparation method of the slurry after hydrolysis of alkoxyaluminum in step (1) includes the following steps: (S1) The reaction between metallic aluminum and fatty alcohol is initiated by heating to a first temperature, and then the reaction is carried out at a second temperature to obtain the first intermediate material; (S2) Add a first portion of water to the first intermediate material and perform pre-hydrolysis at the hydrolysis temperature. During the pre-hydrolysis process, add an aqueous solution of ammonium bicarbonate. After the pre-hydrolysis is completed, the second intermediate material is obtained. (S3) Add a second portion of water to the second intermediate material. After no gas is generated, separate the organic phase and separate the supernatant to obtain the slurry after hydrolysis of the alkoxyaluminum.

10. An alumina strip-shaped carrier, which is prepared according to the preparation method described in any one of the preceding claims; The specific surface area of ​​the alumina strip carrier is ≥220.0 m². 2 .g -1 Hole volume ≥ 0.65 cm³ 3 .g -1 The most probable pore size is ≥9.0nm.

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