Alumina, method of preparation and use thereof

Abstract

The application relates to the field of catalysis, and discloses an aluminum oxide, a preparation method and application thereof, and a solid state 27 The Al magic angle spinning nuclear magnetic resonance spectrum has characteristic peaks between 16-51 ppm, and the electron paramagnetic resonance spectrum of the aluminum oxide has characteristic peaks at g=2.002-2.004. The surface and the interior of the aluminum oxide material provided by the application have F color centers, the aluminum oxide material can activate hydrogen under mild conditions, does not need to exist in the presence of a transition metal species, and catalyzes hydrogenation of a compound containing a carbon-carbon unsaturated bond.

Description

Technical Field

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

[0002] Alumina (Al₂O₃) has many polymorphs, more than 10 known, but mainly three crystal forms: α-Al₂O₃, β-Al₂O₃, and γ-Al₂O₃. Among them, γ-Al₂O₃ is industrially known as activated alumina, and its structure contains O₂. 2- Approximately face-centered close packing, aluminum ions (Al) 3+ Al is irregularly distributed within the octahedral and tetrahedral voids surrounded by oxygen ions. 3+ The coordination mode is either six-coordinate or four-coordinate. In industrial catalysis, γ-Al₂O₃ is widely used as a heterogeneous catalyst support. There is a strong metal-support interaction between it and the metal component. This interaction can not only regulate the electronic properties of the metal component, but also play a key role in determining the morphology of the metal component and maintaining the metal dispersion.

[0003] Five-coordinate Al 3+ It is a six-coordinate Al 3+ (The center of the regular octahedron is Al) 3+ (The six vertices are oxygen anions) lose one oxygen anion to generate. Kwak et al. attributed the strong interaction between alumina and the metal component to the coordinate-unsaturated five-coordinate Al. 3+ However, commercially available alumina does not contain five-coordinated Al. 3+ Therefore, the synthesis of Al-rich five-coordinated compounds is possible. 3+ The synthesis of alumina is both challenging and significant. Only a few patents (CN115155552A, CN113289594A, CN111790381A, CN110586086A, CN104971749A, and CN110302843A) or literature report relevant findings, but the synthetic methods are quite cumbersome. Therefore, developing a simpler synthetic method is necessary. Furthermore, even with five-coordinated Al... 3+ Alumina typically lacks free electrons; the presence of F-centers in alumina is only reported in some physics-oriented studies. These alumina solutions are synthesized using special methods, and the F-center content is extremely low. This leads to the formation of five-coordinated Al... 3+ Methods for obtaining alumina containing a large number of free electrons have not yet been developed. Summary of the Invention

[0004] In order to solve the problems in the prior art, the application provides an alumina, a preparation method and an application thereof, the alumina material has F color centers on the surface and inside, the alumina material can activate hydrogen under mild conditions, does not need transition metal species, and catalyzes hydrogenation of a compound containing a carbon-carbon unsaturated bond.

[0005] The first aspect of the application provides an alumina.

[0006] The alumina has a solid state 27 The Al magic angle spinning nuclear magnetic resonance spectrum has a characteristic peak between 16-51 ppm, and the electron paramagnetic resonance spectrum of the alumina has a characteristic peak at g=2.002-2.004.

[0007] In an embodiment, the ultraviolet-visible diffuse reflectance spectrum of the alumina has characteristic peaks at 207.3 nm, 230.5 nm, 276.2 nm, 360.9 nm, 430.4 nm and 495.6 nm, respectively.

[0008] The second aspect of the application provides a preparation method.

[0009] A method for preparing the alumina of the first aspect, an aluminum compound containing an organic ligand is calcined at 300-800 DEG C in an inert atmosphere, the general formula of the aluminum compound containing an organic ligand is (R)2AlOH, wherein R is C 1-4 carboxyl; or the general formula of the aluminum compound containing an organic ligand is (R)3Al, wherein R is C 1-4 alkyl, C 1-4 alkoxy or C 1-4 carboxyl.

[0010] In an embodiment, the method comprises the following steps: first, the solid powder of the aluminum compound containing an organic ligand is placed in an atmosphere furnace, the inert gas is introduced to replace the air in the furnace, heated to 300-800 DEG C and kept for a certain time, and then naturally cooled to room temperature to obtain the alumina.

[0011] In an embodiment, the aluminum compound containing an organic ligand comprises at least one of basic aluminum acetate, aluminum acetate, aluminum formate, aluminum propionate, aluminum butyrate, aluminum isopropyl alcohol, triethyl aluminum, and triisobutyl aluminum.

[0012] In an embodiment, the inert gas is one of nitrogen, argon and helium.

[0013] In an embodiment, the purity of the inert gas is 99%-99.999%.

[0014] In an embodiment, the flow rate of the inert gas is 1-1000 mL / min, further alternatively 1-50 mL / min, 1-200 mL / min, 1-400 mL / min, 200-600 mL / min, 400-800 mL / min, 600-1000 mL / min.

[0015] In an embodiment, the time for the inert gas to replace the air in the furnace is 10-120 min.

[0016] In an embodiment, the rate of the furnace to reach the preset reaction temperature is 0.1-20 。 C / min.

[0017] In an embodiment, the calcination temperature is further alternatively 300-400℃, 300-600℃, 400-800℃, 600-800℃.

[0018] In an embodiment, the calcination time is 0.1-24 h.

[0019] A third aspect of the present application provides a use.

[0020] The use of the alumina of the first aspect or the alumina prepared by the method of the second aspect in catalyzing hydrogenation reaction of a compound containing carbon-carbon unsaturated bond.

[0021] In an embodiment, the catalyzing hydrogenation reaction of a compound containing carbon-carbon unsaturated bond comprises the following steps: dispersing the alumina in anhydrous toluene, then transferring to a high-pressure reaction kettle, adding a compound containing carbon-carbon unsaturated bond, replacing the air in the kettle with hydrogen, keeping the hydrogen pressure at the reaction pressure, and carrying out the reaction at the preset reaction temperature under sufficient stirring.

[0022] In an embodiment, the compound containing carbon-carbon unsaturated bond comprises an olefin or an alkyne.

[0023] In an embodiment, the compound containing carbon-carbon unsaturated bond comprises at least one of aliphatic olefin, aliphatic alkyne, aromatic olefin, and aromatic alkyne.

[0024] In an embodiment, the compound containing carbon-carbon unsaturated bond comprises at least one of styrene, 3-phenyl-1-propene, 1,2-diphenyl ethylene, n-hexene, cyclohexene, phenylacetylene, 1-propenylbenzene, cyclohexylacetylene, n-hexyne, and 4-octyne.

[0025] In an embodiment, the mass ratio of the alumina and the compound containing carbon-carbon unsaturated bond is 1: (10~100), further optionally 1: (10~20), 1: (10~50), 1: (20~100), 1: (50~100).

[0026] In an embodiment, the reaction pressure is 1~4 MPa, further optionally 1~2 MPa, 3~4 MPa.

[0027] In an embodiment, the reaction temperature is 50~150℃, further optionally 50~100℃, 100~150℃.

[0028] In an embodiment, the reaction time is 1~10 h.

[0029] Advantages

[0030] Compared with the prior art, the present application has the advantages of:

[0031] (1) The F color centers in the alumina catalyst provided by the present application exist in the surface and interior of the alumina, and the F color centers contain five-coordinated Al 3+ ions and free electrons.

[0032] (2) The alumina catalyst provided by the present application can activate hydrogen under mild conditions without the presence of transition metal species, and catalyze the hydrogenation of compounds containing carbon-carbon unsaturated bonds, with a conversion rate of greater than 99.9%.

[0033] (3) The alumina catalyst provided by the present application has stable activity and is not deactivated after 8 cycles. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is the solid-state 27 Al magic angle spinning nuclear magnetic resonance spectrum of F-Al2O3 and γ-Al2O3 in synthesis example 1;

[0035] Figure 2 is the solid-state 27 Al magic angle spinning nuclear magnetic resonance spectrum of F-Al2O3 after CO2 treatment in synthesis example 1;

[0036] Figure 3 is the solid-state 27 Al magic angle spinning nuclear magnetic resonance spectrum of F-Al2O3 after NH3 treatment in synthesis example 1;

[0037] Figure 4 is the solid-state 27 Al magic angle spinning nuclear magnetic resonance spectrum of F-Al2O3 after NO treatment in synthesis example 1;

[0038] Figure 5 is the in situ CO2-FTIR pattern of F-AI2O3 and γ-AI2O3 from Synthesis Example 1;

[0039] Figure 6 is the XRD pattern of F-AI2O3 and γ-AI2O3 from Synthesis Example 1;

[0040] Figure 7 is the HAADF-STEM and FFT pattern of F-AI2O3 from Synthesis Example 1;

[0041] Figure 8 is the EPR spectrogram of F-AI2O3 and γ-AI2O3 from Synthesis Example 1;

[0042] Figure 9 is the UV-Vis DRS spectrogram of F-AI2O3 and γ-AI2O3 from Synthesis Example 1;

[0043] Figure 10 is the solid state 27 Al magic angle spinning nuclear magnetic resonance spectrogram of the alumina material obtained in Synthesis Example 49;

[0044] Figure 11 is the EPR spectrogram of the alumina material obtained in Synthesis Example 49;

[0045] Figure 12 is the solid state 27 Al magic angle spinning nuclear magnetic resonance spectrogram of the alumina material obtained in Synthesis Example 58;

[0046] Figure 13 is the EPR spectrogram of the alumina material obtained in Synthesis Example 58;

[0047] Figure 14 is the solid state 27 Al magic angle spinning nuclear magnetic resonance spectrogram of the alumina material obtained in Synthesis Example 59;

[0048] Figure 15 is the EPR spectrogram of the alumina material obtained in Synthesis Example 59;

[0049] Figure 16 is the conversion time curve plot for the hydrogenation of styrene using F-AI2O3 as catalyst in Catalytic Example 1 and without catalyst using F-AI2O3 as catalyst in Catalytic Comparative Examples 2-3.

[0050] Figure 17 (a) is the H NMR spectrogram of the hydrogenation of styrene using F-AI2O3 as catalyst in Catalytic Example 1, (b) is an enlarged spectrogram; 1 H NMR spectrogram, (b) is an enlarged spectrogram;

[0051] Figure 18 Figure 1 is a graph of the results of a cycle stability test of the catalytic hydrogenation of styrene using F-AI2O3 catalyst of Example 1. DETAILED DESCRIPTION

[0052] In order to make the skilled in the art better understand the technical solutions of the present application, some non-limiting embodiments are further disclosed below to make further detailed description of the present application.

[0053] DEFINITIONS

[0054] The term "F-center" is one of the color centers, which refers to a defect in a transparent crystal formed by a point defect, a pair of point defects, or a group of point defects capturing an electron or a hole. The color center in a metal oxide is called an F-center, which is a negative ion vacancy capturing an electron. The F-center in alumina refers to an oxygen vacancy at a five-coordinated aluminum ion capturing an electron. A single oxygen vacancy capturing one electron and two electrons are called F1 + -center and F1-center, respectively. A pair of oxygen vacancies capturing one electron, two electrons, three electrons, and four electrons are called F2 3+ -center, F2 2+ -center, F2 + -center and F2-center.

[0055] The term "precursor" refers to an existing form before obtaining a target product, and also refers to a rudimentary sample of the target product, i.e., a precursor product that can achieve the target product after some steps.

[0056] In the present application, "room temperature" refers to ambient temperature, which is from about 10°C to about 40°C. In some embodiments, "room temperature" refers to a temperature from about 20°C to about 30°C; in other embodiments, "room temperature" refers to a temperature from about 25°C to about 30°C; in yet other embodiments, "room temperature" refers to 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, etc.

[0057] All numbers disclosed herein are approximations. Each numerical value, however, has a tolerance of ± 10% around or of a range deemed reasonable by one of ordinary skill in the art, such as ± 1%, ± 2%, ± 3%, ± 4%, or ± 5% of the stated value.

[0058] In the present application, it is necessary to point out that "above" and "below" include the number itself, unless otherwise stated.

[0059] Synthesis Example 1

[0060] One gram of basic aluminum acetate solid powder was placed in an alumina crucible, which was then placed in a tube furnace. High-purity nitrogen gas (99.999%) was introduced, with the nitrogen flow rate set at 100 mL / min, the air replacement time at 20 min, and the heating rate at 2℃ / min. The temperature was increased from room temperature to 500℃ and calcined for 4 h. The mixture was then allowed to cool naturally to room temperature, and the gas was turned off to obtain an alumina material rich in F-center (abbreviated as F-Al2O3).

[0061] It is quite intuitive that F-Al2O3 powder is a bright light yellow, while commercial γ-Al2O3 material (hereinafter referred to as γ-Al2O3) powder is white.

[0062] First, F-Al2O3 and γ-Al2O3 were subjected to solid-state treatment. 27 Al magic angle rotation NMR characterization, results are as follows Figure 1 As shown, γ-Al₂O₃ contains only tetracoordinated Al. 3+ Ions (~64 ppm, abbreviated as Al) t ) and six-coordinate Al 3+ Ions (~6 ppm, abbreviated as Al) o ), without five-coordinate Al 3+ Ions (~33 ppm, abbreviated as Al) p F-Al2O3 is rich in Al p Through mathematical fitting, it can be known that its Al p The content is approximately 42%. To obtain the Al content on the F-Al2O3 surface... p The relative content of Al on the surface of F-Al2O3 was quantified by treating F-Al2O3 with CO2, NH3, and NO (gaseous Lewis acids or bases), respectively. p The relative contents of F-Al2O3 after CO2, NH3 and NO treatment were determined by solid-state reaction. 27 Al magic angle rotation NMR characterization, results are as follows Figures 2-4 As shown, from Figures 2-4 As can be seen, gaseous molecules and surface Al p The coordination of Al led to a significant decrease in the intensity of the peak at ~33 ppm, while the corresponding increase in the NMR peak at ~6 ppm clearly indicates that Al p After processing, it is converted to Al. o Based on the mathematical fit before and after the coordination reaction, we quantitatively determine the surface Al... p Accounting for 6% to 9% of the total, this indicates that the surface of F-Al2O3 contains abundant Al. p Site.

[0063] In addition, in-situ CO2-Fourier transform infrared spectroscopy characterization was performed on F-Al2O3 and γ-Al2O3, and the results are as follows: Figure 5As shown. From Figure 5 As can be seen, the in-situ CO2-FTIR of F-Al2O3 is significantly different from that of γ-Al2O3. Their adsorption strength and absorption peak positions are also different. Compared to γ-Al2O3, the surface of F-Al2O3 contains only a small amount of bicarbonate species produced by the reaction of CO2 and -OH (1656–1628, 1436, and 1228 cm⁻¹). -1 ), while there are a large number of monodentate coordinated carbonate species (1538 and 1370 cm). -1 ), produced by the reaction of CO2 and surface-exposed O atoms, and bidentate coordinated carbonate species (1670 and 1320 cm). -1 This is produced by the reaction of CO2 with exposed O and Al atoms on the surface. This indicates that the F-Al2O3 surface contains a relatively high amount of exposed O and Al atoms, meaning the F-Al2O3 surface is rich in Al. p Furthermore, F-Al2O3 and γ-Al2O were characterized by powder X-ray diffraction (XRD), and the results are as follows: Figure 6 As shown. From Figure 6 As can be seen, F-Al2O3 is amorphous compared to the crystalline γ-Al2O3, indicating the presence of highly disordered Al atoms in the crystal lattice. 3+ Ions, indicating Al in the crystal lattice 3+ The complex coordination environment of ions, that is, not only Al t And Al o There is also a large amount of Al p .

[0064] Furthermore, F-Al2O3 was characterized by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and fast Fourier transform (FFT) with spherical aberration correction, and the results are as follows: Figure 7 As shown, Figure 7 This also confirms the amorphous characteristics of F-Al2O3.

[0065] Electron paramagnetic resonance (EPR) spectroscopy was performed on F-Al2O3 and γ-Al2O, and the results are as follows: Figure 8 As shown. From Figure 8 As can be seen, F-Al₂O₃ exhibits a very obvious signal with a g-value of 2.002, which is due to the presence of F or F₂ type color centers, corresponding to unpaired free electrons in single and double oxygen vacancies, respectively. In contrast, γ-Al₂O₃ does not show this signal. To obtain more accurate information about the surface F-center, UV-Vis diffuse reflectance spectroscopy (UV-VisDRS) was performed on F-Al₂O₃, and the results are as follows. Figure 9 As shown. From Figure 9It can be seen that characteristic peaks are observed at 207.3, 230.5, 276.2, 360.9, 430.4 and 495.6 nm, which are attributed to F1-center, F1 + -center, F2-center, F2 + -center, F2 2+ -center and F1 + -center, respectively, indicating that not only unpaired free electrons but also paired free electrons exist on the surface of F-Al2O3. However, γ-Al2O3 does not have these specific absorption peaks. Quantitative tests by direct iodometric titration further show that the surface electron density of F-Al2O3 is 0.35 mmol·g -1 , while γ-Al2O3 cannot reduce I3 - at all. The results are shown in Table 1.

[0066] Table 1. Surface electron density of F-Al2O3 and γ-Al2O3 by direct iodometric titration

[0067]

[0068] I3 - + 2e = 3I - , E θ = 0.545V, KI3 aqueous solution (11.45 μmol·mL -1 ), aqueous starch solution.

[0069] Synthesis Examples 2-8

[0070] The method for preparing F-Al2O3 in Synthesis Examples 2-8 is the same as that in Synthesis Example 1, except that the aluminum compound containing an organic ligand used is different. In Synthesis Examples 2-8, 1 g of aluminum acetate powder, 1 g of aluminum formate powder, 1 g of aluminum propionate powder, 1 g of aluminum butyrate powder, 1 g of aluminum isopropyl alcohol powder, 1 g of triethyl aluminum powder and 1 g of triisobutyl aluminum powder are used instead of basic aluminum acetate powder in Synthesis Example 1, respectively. Accordingly, the F-Al2O3 obtained contains F-center in the surface and inside, and the F-center contains coordination unsaturated Al p and free electrons. The content of Al p in them is about 42%, and the surface Al p accounts for 6%-9% of the total.

[0071] Synthesis Examples 9-10

[0072] The method for preparing F-Al2O3 in Synthesis Examples 9-10 is the same as that in Synthesis Example 1, except that the inert atmosphere used is different. In Synthesis Examples 9-10, high-purity argon (99.999%) and high-purity helium (99.999%) are used instead of high-purity nitrogen in Synthesis Example 1. The F-Al2O3 obtained accordingly contains F-centers in both the surface and the interior, and the F-centers contain coordination-unsaturated Al p and free electrons. The content of Al p is about 42%, and the surface Al p accounts for 6-9% of the total.

[0073] Synthesis Examples 11-21

[0074] The method for preparing F-Al2O3 in Synthesis Examples 11-21 is the same as that in Synthesis Example 1, except that the calcination temperature is different. In Synthesis Examples 11-21, the calcination is carried out at 300 。 C, 350 。 C, 400 。 C, 450 。 C, 550 。 C, 600 。 C, 650 。 C, 700 。 C, 750 。 C and 800 。 C, respectively. The F-Al2O3 obtained accordingly contains F-centers in both the surface and the interior, and the F-centers contain coordination-unsaturated Al p and free electrons. The content of Al p is about 42%, and the surface Al p accounts for 6-9% of the total.

[0075] Synthesis Examples 22-32

[0076] The method for preparing F-Al2O3 in Synthesis Examples 22-32 is the same as that in Synthesis Example 1, except that the calcination time is different. In Synthesis Examples 22-32, the calcination is carried out for 0.1 h, 1 h, 2 h, 3 h, 6 h, 8 h, 10 h, 12 h, 16 h, 20 h and 24 h, respectively. The F-Al2O3 obtained accordingly contains F-centers in both the surface and the interior, and the F-centers contain coordination-unsaturated Al p and free electrons. The content of Al p is about 42%, and the surface Al p accounts for 6-9% of the total.

[0077] Synthesis Examples 33-39

[0078] The methods for preparing F-Al2O3 in Synthesis Examples 33-39 are the same as in Synthesis Example 1, except that the heating rate differs from that in Synthesis Example 1. In Synthesis Examples 33-39, the heating rate is 0.1... 。 C / min, 0.5 。 C / min, 1 。 C / min, 5 。 C / min, 10 。 C / min, 15 。 C / min and 20 。 Heating to the calcination temperature at a rate of C / min, the resulting F-Al₂O₃ contains F-centers both on the surface and inside, with the F-centers containing coordinate-unsaturated Al atoms. p and free electrons. Its Al p The content of all is about 42%, and the surface Al p They account for 6% to 9% of the total.

[0079] Synthesis Examples 40-48

[0080] The methods for preparing F-Al₂O₃ in Synthesis Examples 40-48 are the same as in Synthesis Example 1, except that the nitrogen flow rate differs. Synthesis Examples 40-48 used nitrogen flow rates of 1 mL / min, 10 mL / min, 20 mL / min, 50 mL / min, 200 mL / min, 400 mL / min, 600 mL / min, 800 mL / min, and 1000 mL / min, respectively. The resulting F-Al₂O₃ contained F-centers both on the surface and inside, with the F-centers containing coordinate-unsaturated Al atoms. p and free electrons. Its Al p The content of all is about 42%, and the surface Al p They account for 6% to 9% of the total.

[0081] Synthetic comparative example 49

[0082] The method for preparing alumina material in Comparative Example 49 was the same as that in Synthesis Example 1, except that an air atmosphere was used during calcination, resulting in the same alumina material. The alumina material obtained in this example was subjected to solid-state treatment. 27 Al magic angle rotation NMR characterization, results as follows Figure 10 As shown. The alumina material obtained in this embodiment was subjected to EPR spectroscopy, and the results are as follows. Figure 11 As shown. From Figure 10 and 11As can be seen, the alumina material obtained in this embodiment does not contain F-centers on either the surface or inside. The reason for the absence of F-centers is that oxygen in the air or Lewis bases will react with the five-coordinated Al. 3+ The (Lewis acid) reaction generates six-coordinate aluminum ions. This result is similar to the traditional alumina material surface containing hydroxyl groups or water-sealed ends, and does not contain five-coordinate Al. 3+ Furthermore, free electrons do not exist in an oxidizing atmosphere; they will be oxidized by oxygen.

[0083] Synthetic comparative examples 50-57

[0084] The methods for preparing alumina materials in Comparative Examples 50-57 correspond to those in Synthetic Examples 2-8, with the only difference being that an air atmosphere was used during calcination, resulting in alumina materials that do not contain F-centers on the surface or inside.

[0085] Synthetic Comparative Example 58

[0086] The method for preparing alumina material in Comparative Example 59 was the same as that in Synthetic Example 1, except that the aluminum compound containing the organic ligand was used. In Comparative Example 59, 1 g of aluminum trifluoroacetate powder was used instead of 1 g of basic aluminum acetate powder in Synthetic Example 1, resulting in the alumina material. The alumina material obtained in this example was subjected to solid-state reaction. 27 Al magic angle rotation NMR characterization, results as follows Figure 12 As shown. The alumina material obtained in this embodiment was subjected to EPR spectroscopy, and the results are as follows. Figure 13 As shown. From Figure 12 and 13 As can be seen from the data, the alumina material obtained in this embodiment does not contain five-coordinated Al on its surface or inside. 3+ The presence of a CH bond in the organic ligand indicates that the organic ligand contains a CH bond moiety, which is important for obtaining five-coordinate Al. 3+ And F-center is very important.

[0087] Synthetic comparative examples 59-62

[0088] The method for preparing alumina materials in comparative examples 59-62 is the same as that in synthetic example 1. The only difference from synthetic example 1 is that aluminum compounds without organic ligands are used. In comparative examples 59-62, 1 g of aluminum hydroxide powder, 1 g of aluminum nitrate powder, 1 g of aluminum sulfate powder, and 1 g of aluminum carbonate powder are used to replace 1 g of basic aluminum acetate powder in synthetic example 1, respectively, and alumina materials are obtained accordingly.

[0089] The alumina material obtained from Comparative Example 59 was subjected to solid-state reaction. 27Al magic angle spinning nuclear magnetic resonance characterization, the results are shown in Figure 12 The EPR spectrum of the alumina material obtained in this example was detected, and the results are shown in Figure 13 From Figure 12 and 13 It can be seen that the alumina material obtained in Comparative Synthesis Example 59 does not contain F-centers on the surface and inside.

[0090] The surface and inside do not contain F-centers.

[0091] Catalytic Example 1

[0092] The F-Al2O3 obtained in Synthesis Example 1 was used to catalyze the hydrogenation reaction of styrene, and the specific steps were as follows: 50 mg of F-Al2O3 catalyst was dispersed in 5 mL of anhydrous toluene, then transferred to a 50 mL high-pressure reaction kettle, and then 500 mg of styrene was added. Next, the air in the kettle was replaced with normal pressure H2, and 1 MPa H2 was filled in the reaction kettle, and the preset reaction temperature was 100°C, and the reaction was carried out under sufficient stirring. The product was determined by gas chromatography and 1 H NMR, and the results are shown in Figure 14 and 15 From Figure 14 It can be seen that F-Al2O3 shows good hydrogenation reaction activity, and the conversion rate of styrene reaches more than 99.9% within 4 h. Only toluene (marked as #) and styrene (marked as *) exist before the reaction. Only toluene (marked as #) and ethylbenzene (marked as +) exist after the reaction. Figure 15 It is confirmed that the substrate is completely converted.

[0093] In addition, under the same conditions, the F-Al2O3 obtained in Synthesis Example 1 was repeatedly used to catalyze the hydrogenation reaction of styrene to test its cycle stability, and the results are shown in Figure 16 The F-Al2O3 catalyst is still not deactivated after 8 cycles, indicating that the active site structure of the surface catalyst has good stability.

[0094] Under the same conditions, the pressure of hydrogen was adjusted to 2 MPa, 3 MPa and 4 MPa respectively, and the hydrogenation reaction was carried out respectively, and the results showed that the conversion rate of styrene reached more than 99.9% within 4 h.

[0095] Under the same conditions, the reaction temperature was adjusted to 50°C and 150°C respectively, and the results showed that the conversion rate of styrene reached more than 99.9% within 6 h.

[0096] Under the same conditions, the amount of styrene was adjusted so that the mass ratio of F-Al2O3 catalyst to styrene was 1:20, 1:50 and 1:100, respectively. The results showed that the conversion rate was greater than 99.9% within 10 hours.

[0097] Catalytic Examples 2-10

[0098] The steps of catalyzing the hydrogenation reaction of the compound containing carbon-carbon unsaturated bond in Catalytic Examples 2-10 were the same as those in Catalytic Example 1, except that the reaction substrates used were different. The reaction substrates shown in Table 2 (500 mg) were used to replace styrene (500 mg) in Catalytic Example 1, respectively, to carry out the hydrogenation reaction, and the results are shown in Table 2. The conversion rate was greater than 98.5% within 8 hours.

[0099] Table 2 Reaction substrates, products and conversion rates in Catalytic Examples 2-10

[0100]

[0101] Catalytic Comparative Examples 11-12

[0102] The steps of catalyzing the hydrogenation reaction of styrene in Catalytic Comparative Examples 11-12 were the same as those in Catalytic Example 1, except that the catalyst used in Catalytic Comparative Example 11 was γ-Al2O3, and no catalyst was used in Catalytic Comparative Example 12. The conversion rate of the product was determined by gas chromatography, and the results are shown in Table 3. Figure 14 As can be seen from Table 3, Figure 14 there was no observed reactivity in the control experiments without using a catalyst or using γ-Al2O3 without F-center.

[0103] The above descriptions are only preferred embodiments of the present application and are not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An aluminum oxide characterized in that, The solid state of the alumina 27 The Al magic angle spinning nuclear magnetic resonance spectrum has a characteristic peak between 16-51 ppm, the electron paramagnetic resonance spectrum of the alumina has a characteristic peak at g = 2.002-2.004, and the alumina contains F-centers.

2. The aluminum oxide of claim 1, wherein, The ultraviolet-visible diffuse reflectance spectrum of the alumina has characteristic peaks at 207.3 nm, 230.5 nm, 276.2 nm, 360.9 nm, 430.4 nm and 495.6 nm, respectively, and the F-center contains one or more of a coordination unsaturated Al p and a free electron, the F-center being one or more of a F1-center, a F1 + -center, a F2-center, a F2 + -center, a F2 2+ -center.

3. A process for the production of the alumina according to claim 1 or 2, characterized in that, An aluminum compound containing an organic ligand having a general formula of (R)2AIOH, wherein R is C 1-4 alkyl, C 1-4 alkyl, C 1-4 alkyl, C 1-4 alkyl, C 4. The method of claim 3, wherein, The aluminum compound containing an organic ligand includes at least one of basic aluminum acetate, aluminum acetate, aluminum formate, aluminum propionate, aluminum butyrate, aluminum isopropylate, triethylaluminum, and triisobutylaluminum.

5. The method of claim 3, wherein, The inert gas is at least one of nitrogen, argon, and helium.

6. Use of the aluminum oxide according to claim 1 or 2 in a catalytic hydrogenation reaction of a compound containing a carbon-carbon unsaturated bond.

7. Use according to claim 6, characterized in that, The compound containing a carbon-carbon unsaturated bond includes at least one of styrene, 3-phenyl-1-propene, 1,2-diphenyl ethylene, n-hexene, cyclohexene, phenylacetylene, 1-propenylbenzene, cyclohexylacetylene, n-hexyne, and 4-octyne.

8. Use according to claim 6, characterized in that, The mass ratio of the aluminum oxide to the compound containing a carbon-carbon unsaturated bond is 1:(10-100).

9. The use according to claim 6, characterized in that, The reaction temperature is 50-150°C.

Images