A selective oxidation catalyst, its preparation method and application

Abstract

This application belongs to the technical field of catalysts, and particularly relates to a selective oxidation catalyst, a preparation method thereof, and an application thereof. This application provides a selective oxidation catalyst, a preparation method thereof, and an application thereof. Among them, the selective catalytic oxidation catalyst includes a carrier and Pd with an expanded lattice spacing. The catalyst after lattice expansion can promote the selective catalytic oxidation reaction, thereby solving the technical problem in the prior art that it is difficult to obtain a catalyst with high catalytic activity and catalytic stability when loading catalyst particles on a carrier.

Description

Technical Field

[0001] The present application belongs to the field of catalyst technology, and in particular relates to a selective oxidation catalyst and a preparation method and application thereof. Background Art

[0002] With the rapid development of reaction intermediates, perfumes, and food processing in recent years, there is a need to provide selective oxidation metal catalysts with high catalytic activity and stability.

[0003] Since selective catalytic oxidation needs to be carried out under high temperature conditions, metal catalyst particles are prone to agglomeration during the high-temperature selective catalytic oxidation reaction, resulting in reduced activity and stability of the metal catalyst. In the prior art, the metal catalyst particles are generally loaded on a carrier to improve the stability of the metal catalyst. However, the activity and stability of the selective oxidation of the metal catalyst loaded on the carrier in the prior art need to be improved. Summary of the Invention

[0004] In view of this, the present application provides a selective oxidation catalyst and its preparation method and application, which are used to solve the technical problem in the prior art that it is difficult to obtain a catalyst with high catalytic activity and catalytic stability by loading catalyst particles on a carrier.

[0005] In a first aspect, the present application provides a selective catalytic oxidation catalyst, characterized in that the selective catalytic oxidation catalyst comprises Pd particles doped with light atoms and a carrier;

[0006] The surface of the carrier is loaded with the Pd particles doped with light atoms.

[0007] Preferably, the light atom is selected from a hydrogen atom, a nitrogen atom or a carbon atom.

[0008] Preferably, the carrier is selected from carbon black and / or metal organic framework.

[0009] Preferably, the light atom is selected from hydrogen atoms.

[0010] It should be noted that after Pd is doped with H atoms, it can not only expand the lattice spacing and improve the catalytic activity of the catalyst, but also, since selective catalytic oxidation usually reacts at high temperatures, and Pd is easily oxidized under high temperature conditions, the catalytic performance decreases over time and the catalytic performance is unstable. In this application, by embedding H atoms into the Pd lattice, the expansion of the H atom lattice can reduce the occurrence of Pd metal particles being oxidized by oxygen during the selective catalytic oxidation process, thereby improving the stability of the selective catalytic oxidation catalyst.

[0011] Preferably, the support is selected from metal organic frameworks.

[0012] Preferably, the metal-organic framework is MOFs-NH2.

[0013] It should be noted that after the metal catalyst particles are loaded on the carrier, the carrier and the metal catalyst particles are physically adsorbed and there is no interaction. Not only are they prone to falling, agglomerating, and deforming during the catalytic process, but the catalytic stability of the catalyst is difficult to guarantee. In this application, a metal-organic framework is used as the carrier of the metal catalyst particles, which is an organic-inorganic hybrid material composed of organic ligands and metal ions or clusters. Therefore, when the metal-organic framework is used as the carrier of the metal catalyst particles, the metal catalyst particles can form coordination bonds with metal ions to improve the catalytic stability of the catalyst.

[0014] The second aspect of this application provides a method for preparing a selective oxidation catalyst, which includes the following steps:

[0015] Step 1: Disperse the carrier loaded with Pd particles in a solution containing light atoms to obtain a mixed solution;

[0016] Step 2: Stir and heat the mixed solution to react to obtain a selective oxidation catalyst;

[0017] In Step 2, the temperature of the stirring and heating reaction is 90°C to 160°C.

[0018] It should be noted that during the stirring and heating process, the solution containing light atoms releases active light atoms, which are embedded in the lattice of Pd, expanding the lattice of Pd to obtain Pd particles doped with light atoms; at the same time, the stirring and heating process at 90°C to 160°C is relatively mild and will not damage the structure of the carrier.

[0019] Preferably, in Step 2, the time of the stirring and heating reaction is 0.25 h to 15 h.

[0020] It should be noted that by controlling the heating time, the degree of lattice expansion can be regulated to obtain a catalyst with excellent selective catalytic oxidation performance.

[0021] Preferably, in Step 1, the solution containing light atoms is an N,N-dimethylformamide solution;

[0022] In Step 2, the temperature of the stirring and heating reaction is 140°C to 160°C;

[0023] The time of the stirring and heating reaction is 10 h to 15 h.

[0024] Preferably, in Step 1, the solution containing light atoms is a urea solution;

[0025] In Step 2, the temperature of the stirring and heating reaction is 90°C to 120°C;

[0026] The time of the stirring and heating reaction is 0.25 h to 5 h.

[0027] It should be noted that in Step 2, after the stirring and heating reaction ends, the product selective oxidation catalyst also needs to be separated from the solution by centrifugation, and then the product selective oxidation catalyst is washed multiple times with solvents such as deionized water and ethanol, and then dried to obtain the selective oxidation catalyst.

[0028] Preferably, in Step 1, the solution containing light atoms is a glucose solution;

[0029] In Step 2, the temperature of the stirring and heating reaction is 180 °C to 250 °C;

[0030] The time of the stirring and heating reaction is 0.25 h to 0.5 h.

[0031] Preferably, the carrier loaded with Pd particles is Pd / MOFs-NH2.

[0032] Preferably, the carrier loaded with Pd particles is Pd / C.

[0033] Preferably, the preparation method of the Pd / MOFs-NH2 includes the steps:

[0034] Step 101: Mix metal chloride, 2-aminoterephthalic acid and an acidic solution of N,N-dimethylformamide evenly to obtain a MOFs-NH2 precursor solution;

[0035] Step 102: Carry out a hydrothermal reaction on the MOFs-NH2 precursor solution to obtain MOFs-NH2;

[0036] Step 103: Stir the MOFs-NH2, Pd(OAc)2 and KBr with methanol to obtain Pd / MOFs-NH2;

[0037] In Step 102, the temperature of the hydrothermal reaction is 110 °C to 140 °C, and the time is 10 h to 15 h;

[0038] In Step 103, the temperature of the stirring reaction is 20 °C to 30 °C, and the time is 10 h to 14 h;

[0039] It should be noted that in Step 102, after the hydrothermal reaction ends, the product MOFs-NH2 also needs to be separated from the solution by centrifugation, and then the product MOFs-NH2 is washed multiple times with solvents such as deionized water and ethanol, and then dried to obtain MOFs-NH2; after the stirring ends, centrifugation, washing of the product, and then drying are also required to obtain Pd / MOFs-NH2;

[0040] Meanwhile, refer to the attachedFigure 5 , 6 It can be seen that the Pd particle size supported on the surface of the metal-organic framework MOFs-NH2 is about 8 nm, without agglomeration, and is uniformly supported on the surface of the metal-organic framework MOFs-NH2, indicating that in step 103, KBr can promote the reduction of Pd(OAc)2 to Pd with a particle size of about 8 nm and load it on the metal-organic framework MOFs-NH2.

[0041] Preferably, in step 101, the molar ratio of the metal chloride to the 2-aminoterephthalic acid is 1:1.

[0042] Preferably, the metal chloride is zirconium tetrachloride.

[0043] Preferably, in step 103, the molar ratio of Pd(OAc)2 to KBr is 1:2.2.

[0044] The third aspect of the present application provides the application of the above selective oxidation catalyst in catalyzing benzyl alcohol or tetrahydroquinoline.

[0045] In summary, the present application provides a selective oxidation catalyst, its preparation method and application. Among them, the selective catalytic oxidation catalyst includes Pd particles doped with light atoms and a carrier, and the Pd particles doped with light atoms are supported on the surface of the carrier; the loading of Pd particles on the carrier not only helps to improve the catalytic stability of Pd particles, but also, after the Pd particles are doped with light atoms, the light atoms are embedded in the lattice of Pd, expanding the lattice spacing, improving the oxygen activation ability of the catalyst, and promoting the selective catalytic oxidation reaction, thus solving the technical problem in the prior art that it is difficult to obtain a catalyst with high catalytic activity and catalytic stability when the catalyst particles are supported on the carrier. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0047] Figure 1 XRD patterns of MOFs-NH2, Pd / MOFs-NH2, and PdH / MOFs-NH2 prepared in Example 1 of the present application from 0 to 50°;

[0048] Figure 2 XRD patterns of MOFs-NH2, Pd / MOFs-NH2, and PdH / MOFs-NH2 prepared in Example 1 of the present application from 35 to 50°;

[0049] Figure 3 The lattice spacing of Pd particles in Pd / MOFs-NH2 prepared in Example 1 of this application;

[0050] Figure 4 The lattice spacing of PdH particles in PdH / MOFs-NH2 prepared in Example 1 of this application;

[0051] Figure 5 SEM image of MOFs-NH2 prepared in Example 1 of this application;

[0052] Figure 6 TEM image of Pd / MOFs-NH2 prepared in Example 1 of this application;

[0053] Figure 7 TEM image of PdH / MOFs-NH2 prepared in Example 1 of this application;

[0054] Figure 8 The conversion rate and benzaldehyde selectivity of Pd / MOFs-NH2 and PdH / MOFs-NH2 prepared in Example 1 of this application in the catalytic selective oxidation reaction of benzyl alcohol over time;

[0055] Figure 9 The recycling ability of Pd / MOFs-NH2 prepared in Example 1 of this application in the catalytic selective oxidation reaction of benzyl alcohol;

[0056] Figure 10 The recycling ability of PdH / MOFs-NH2 prepared in Example 1 of this application in the catalytic selective oxidation reaction of benzyl alcohol;

[0057] Figure 11 The EPR test results of Pd / MOFs-NH2 and PdH / MOFs-NH2 prepared in Example 1 of this application;

[0058] Figure 12 The XPS results of Pd / MOFs-NH2 prepared in Example 1 of this application after catalytic selective oxidation of benzyl alcohol;

[0059] Figure 13 The XPS results of PdH / MOFs-NH2 prepared in Example 1 of this application after catalytic selective oxidation of benzyl alcohol;

[0060] Figure 14 XRD patterns of PdN-15min, PdN-1h, PdN-4h prepared in Examples 2-4 of this application and commercial Pd / C;

[0061] Figure 15 The lattice spacing of Pd in commercial Pd / C;

[0062] Figure 16The lattice spacing of PdN in the PdN-1h catalyst prepared in Example 2

[0063] Figure 17 The substrate conversion rates of PdN-15min, PdN-1h, PdN-4h prepared in Examples 2-4 of this application and commercial Pd / C for the dehydrogenation of tetrahydroquinoline Detailed implementation manners

[0064] This application provides a selective oxidation catalyst, its preparation method and application, which are used to solve the technical problem that it is difficult to obtain a catalyst with high catalytic activity and catalytic stability by loading catalyst particles on a carrier in the prior art

[0065] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the protection scope of this application

[0066] Among them, the reagents or raw materials used in the following embodiments are all commercially available or self-made; the term explanations used in the embodiments of this application are as follows

[0067] EPR: Electron paramagnetic resonance

[0068] XRD: X-ray powder diffraction

[0069] TEM: Transmission electron microscope

[0070] SEM: Field emission scanning electron microscope

[0071] Example 1

[0072] This Example 1 provides a preparation method of PdH / MOFs-NH2, where MOFs-NH2 is UiO-66-NH2, and the preparation method includes the following steps

[0073] Step 1, prepare the metal-organic framework UiO-66-NH2

[0074] First, add 52 mg of metal chloride zirconium tetrachloride and 39.5 mg of 2-aminoterephthalic acid to 50 mL of DMF, then add 6 mL of glacial acetic acid, and then stir at room temperature for 30 min to obtain a metal-organic framework UiO-66-NH2 precursor solution

[0075] First, transfer the metal-organic framework UiO-66-NH2 precursor solution into the inner liner of the reaction kettle, then place the inner liner of the polytetrafluoroethylene reaction kettle into the high-pressure reaction kettle. Subsequently, carry out a hydrothermal reaction at 120 °C under high temperature and pressure for 12 h. After the hydrothermal reaction, centrifuge the mixture, wash it twice with DMF and ethanol respectively, and vacuum dry it at 120 °C to obtain UiO-66-NH2.

[0076] Step 2: Prepare the metal-organic framework Pd / UiO-66-NH2 loaded with Pd particles

[0077] First, add 50 mg of UiO-66-NH2 to 25 ml of methanol and ultrasonically disperse it until homogeneous. Stir at room temperature for 30 min, then add 11 mg of palladium acetylacetonate and 27 mg of KBr and stir at room temperature for 10 h to 12 h. After the reaction is completed, cool it, then centrifuge it, wash it twice with DMF and ethanol respectively, and vacuum dry it overnight at 60 °C to obtain the metal-organic framework Pd / UiO-66-NH2. Among them, the stirring speed of the reaction is 600 revolutions per minute, and the centrifugation speed is 8000 revolutions per minute.

[0078] Step 3: Prepare the selective oxidation catalyst PdH / UiO-66-NH2

[0079] First, add 50 mg of Pd / UiO-66-NH2 prepared in Step 2 to 5 mL of DMF and ultrasonically disperse it until homogeneous to obtain a mixture. Then, continuously stir the mixture at 150 °C for 12 h. After the reaction is completed, centrifuge the mixture, wash it twice with DMF and ethanol respectively, and vacuum dry it at 60 °C to obtain PdH / UiO-66-NH2; among them, the stirring speed of the reaction is 600 revolutions per minute, and the centrifugation speed is 8000 revolutions per minute.

[0080] Example 2

[0081] This Example 2 provides a preparation method of PdN / C, and the preparation method includes the following steps:

[0082] First, add 20 mg of commercial 5 wt% Pd / C and 20 mg of urea to 10 mL of water and ultrasonically disperse it until homogeneous to obtain a mixture. Then, continuously stir the mixture at 100 °C for 15 min. After the reaction is completed, centrifuge the mixture, wash it twice with water and ethanol respectively, and vacuum dry it at 60 °C to obtain the reaction product PdN / C, denoted as PdN-15 min; among them, the stirring speed of the reaction is 600 revolutions per minute, and the centrifugation speed is 10000 revolutions per minute.

[0083] Example 3

[0084] Example 3 provides a preparation method of PdN / C. The difference in the steps of the preparation method from Example 2 is that the stirring reaction is for 1 h, and the reaction product is denoted as PdN-1h.

[0085] Example 4

[0086] Example 4 provides a preparation method of PdN / C. The difference in the steps of the preparation method from Example 2 is that the stirring reaction is for 4 h, and the reaction product is denoted as PdN-4h.

[0087] Example 5

[0088] Example 5 provides a preparation method of PdC. The preparation method includes the following steps:

[0089] Step 1: Place 2 mg of Pd particles, 10 mg of glucose, and 4 ml of oleylamine in a 25 ml reaction flask. After vigorously stirring for 15 minutes, heat in an oil bath at 200 °C for 20 minutes. After the reaction ends, naturally cool to room temperature;

[0090] Step 2: Centrifuge at a speed of 12,000 rpm for 10 minutes to obtain the product. Wash the product with ethanol 3 times in sequence, and then dry in a vacuum drying oven at 60 °C to obtain PdC.

[0091] It should be noted that in this example, by doping C into the lattice of Pd, the lattice of Pd is expanded, and the selective catalytic oxidation performance of Pd is improved.

[0092] Example 6

[0093] Example 6 performs qualitative analysis and structural analysis on the MOFs-NH2, Pd / MOFs-NH2, and PdH / MOFs-NH2 prepared in Example 1.

[0094] Among them, the XRD patterns of MOFs-NH2, Pd / MOFs-NH2, and PdH / MOFs-NH2 are as shown in Figure 1 and 2 As shown, it can be seen from Figure 1 and 2 that compared with Pd / MOFs-NH2, PdH / MOFs-NH2 has no peak at 40.1°, but a new peak appears at 39.0°, indicating that the peak of Pd in PdH / MOFs-NH2 shifts to a smaller angle, which means that the lattice of Pd has expanded.

[0095] The lattice spacings of Pd / MOFs-NH2 and PdH / MOFs-NH2 are as shown in Figure 3 and 4 As shown, it can be seen from Figure 3 and 4It can be seen that the lattice spacing of Pd / MOFs-NH2 is 0.225 nm, which is the same as the (111) crystal plane of Pd. The lattice spacing of PdH / MOFs-NH2 is 0.231 nm, indicating that during the heating and stirring reaction of Pd / UiO-66-NH2 in DMF, DMF releases hydrogen atoms, which are doped into Pd, promoting lattice expansion of Pd.

[0096] The scanning electron microscope images and transmission electron microscope images of MOFs-NH2, Pd / MOFs-NH2, and PdH / MOFs-NH2 are as Figure 5 、 6 and 7 shown. It can be seen from Figure 5 、 6 and 7 that the metal-organic framework MOFs-NH2 prepared in step 1 of Example 1 presents an octahedral structure with uniform particle size. The Pd particles in the metal-loaded Pd particle metal-organic framework Pd / UiO-66-NH2 prepared in step 2 are Pd nanoparticles, which are uniformly distributed on the surface of UiO-66-NH2. At the same time, compared with the metal-organic framework Pd / UiO-66-NH2 loaded with Pd particles, the selective oxidation catalyst PdH / UiO-66-NH2 prepared in step 3 has a stable structure, indicating that the stirring and heating process is relatively mild and does not damage the structure of the metal-organic framework MOFs-NH2.

[0097] Example 7

[0098] In this Example 7, the selective catalytic oxidation activity and stability of Pd / MOFs-NH2 and PdH / MOFs-NH2 prepared in Example 1 were analyzed. The analysis steps included: first, adding 5 ml of xylene, 5 mg of catalyst, and 0.5 mmol of xylene into a 25 ml round-bottom flask and ultrasonicating them evenly. Then, placing the round-bottom flask in an oil bath and starting the reaction at 120 °C. Installing a condenser reflux device, taking 100 μL of the mixed solution in the reaction every 30 minutes, centrifuging and taking 50 μL of the supernatant into 950 μL of ethanol, and using gas chromatography-mass spectrometry to detect the reaction results.

[0099] Among them, the activity analysis results of Pd / MOFs-NH2 and PdH / MOFs-NH2 are as Figure 8 、 11 shown. It can be seen from Figure 8 that compared with Pd / MOFs-NH2, PdH / MOFs-NH2 has a higher conversion rate of benzyl alcohol, which has reached 92% after 120 minutes. At the same time, as shown by the EPR test results in Figure 11 , the signal of DMPO-OH of PdH / MOFs-NH2 after oxygen is stronger than that of Pd / UiO-66-NH2, indicating that the former has stronger oxygen activation ability.

[0100] The stability analysis results of Pd / MOFs-NH2 and PdH / MOFs-NH2 are as follows Figure 9 , 10 shown. From Figure 9 , 10 it can be seen that after Pd / MOFs-NH2 is used continuously for 4 times, its catalytic activity decreases significantly, while after PdH / MOFs-NH2 is used continuously for 10 times, its catalytic activity has no obvious decrease. This shows that after the lattice expansion of Pd, the catalytic stability of PdH / MOFs-NH2 can be improved;

[0101] To further explore the reason for the high catalytic stability of PdH / MOFs-NH2, XPS analysis was carried out on Pd / MOFs-NH2 and PdH / MOFs-NH2. The results are as follows Figures 12 - 13 shown. It was found that after the selective catalytic oxidation of Pd / MOFs-NH2, the electron binding energy of Pd in the catalyst shifted to a higher valence state, while the electron binding energy of PdH / MOFs-NH2 did not change significantly. This indicates that during the selective catalytic oxidation process, the Pd particles in Pd / MOFs-NH2 were oxidized, resulting in a decrease in the catalytic ability of Pd / MOFs-NH2.

[0102] Example 8

[0103] In this Example 8, qualitative analysis and structural analysis were carried out on PdN-15min, PdN-1h, and PdN-4h prepared in Examples 2-4.

[0104] Among them, the XRD patterns of PdN-15min, PdN-1h, and PdN-4h are as follows Figure 14 shown. From Figure 14 it can be seen that as the heating time prolongs, the XRD peaks of Pd shift to a smaller angle, indicating that as the heating time prolongs, the degree of lattice expansion increases.

[0105] The lattice spacings of Pd / C and PdN-1h are as follows Figure 15 and 16 shown. From Figure 15 and 16 it can be seen that the lattice spacing of Pd / C is 0.224 nm, which is the same as the (111) crystal plane of Pd, while the lattice spacing of PdN-1h is 0.229 nm. This indicates that during the heating and stirring reaction process of adding Pd / C to the urea solution, the urea solution releases N atoms, which are doped into Pd, promoting the lattice expansion of Pd.

[0106] Example 9

[0107] Example 9 was used to analyze the selective catalytic oxidation activities of PdN-15min, PdN-1h, PdN-4h prepared in Examples 2-4 and commercial Pd / C. The analysis steps were as follows: First, add 2 ml of xylene, 0.1 mmol of benzyl alcohol, and 10 mg of catalyst to a 25 ml round-bottom flask and ultrasonically mix them evenly. Then, place the round-bottom flask in an oil bath and heat it to 130 °C. Install a condenser reflux device. Take 100 μL of the mixed solution in the reaction every 2 h, centrifuge it, and take 50 μL of the supernatant and add it to 950 μL of ethanol. Use gas chromatography-mass spectrometry to detect the reaction results.

[0108] Among them, the activity analysis results of PdN-15min, PdN-1h, PdN-4h and commercial Pd / C are as Figure 17 shown. The substrate conversion rate of commercial Pd / C is the worst, while that of PdN-4h is the best. Therefore, the embedding of nitrogen atoms into the lattice of Pd can also improve the catalytic ability of the catalyst for the oxidative dehydrogenation of tetrahydroquinoline after the lattice of Pd expands. This shows that doping various light atoms, such as hydrogen atoms, nitrogen atoms or carbon atoms, to expand the lattice of Pd can improve the catalytic performance of the selective oxidation catalyst.

[0109] The above are only the preferred embodiments of the present application. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A selective oxidation catalyst for catalyzing benzyl alcohol or tetrahydroquinoline, characterized in that, The selective oxidation catalyst includes Pd particles doped with light atoms and a metal-organic framework; The Pd particles doped with light atoms are supported on the surface of the metal-organic framework, and the light atoms are selected from hydrogen atoms or nitrogen atoms; The preparation method of the selective oxidation catalyst includes the following steps: Step 1: Disperse the metal-organic framework loaded with Pd particles in a solution containing light atoms to obtain a mixed solution; Step 2: Stir and heat the mixed solution for reaction to obtain the selective oxidation catalyst; In Step 1, the solution containing light atoms is an N,N-dimethylformamide solution, and in Step 2, the temperature of the stirring and heating reaction is 140°C to 160°C, and the time is 10 h to 15 h; Or in Step 1, the solution containing light atoms is a urea solution, and in Step 2, the temperature of the stirring and heating reaction is 90°C to 120°C, and the time is 0.25 h to 5 h.

2. A selective oxidation catalyst for catalyzing benzyl alcohol or tetrahydroquinoline according to claim 1, characterized in that, The metal-organic framework loaded with Pd particles is Pd / MOFs-NH2; The preparation method of the Pd / MOFs-NH2 includes the steps: Step 101: Mix metal chloride, 2-aminoterephthalic acid, and an acidic solution of N,N-dimethylformamide evenly to obtain a MOFs-NH2 precursor solution; Step 102: Perform a hydrothermal reaction on the MOFs-NH2 precursor solution to obtain MOFs-NH2; Step 103: Stir the MOFs-NH2, Pd(OAc)2, and KBr with methanol to obtain Pd / MOFs-NH2; In Step 102, the temperature of the hydrothermal reaction is 110°C to 140°C, and the time is 10 h to 15 h; In Step 103, the temperature of the stirring reaction is 20°C to 30°C, and the time is 10 h to 14 h.

3. Application of the selective oxidation catalyst according to any one of claims 1-2 for catalyzing the selective oxidation of benzyl alcohol or tetrahydroquinoline in the catalysis of benzyl alcohol or tetrahydroquinoline.

Images