Application of a platinum-carbon catalyst-loaded electrode in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds

Abstract

The present invention belongs to the field of preparation of electrodes and their synthetic application technology, and discloses an application of an electrode of a platinum-carbon catalyst in the oxidation reaction of benzylic carbon-hydrogen bonds of aromatic compounds. In the present invention, the electrode of the platinum-carbon catalyst provided is used as an electrochemical reaction cathode, so that the benzylic carbon-hydrogen bonds of aromatic compounds are subjected to oxidation reaction under mild conditions such as room temperature and air atmosphere to obtain oxidation products. The preparation process of the electrode of the platinum-carbon catalyst is simple and safe, and the raw materials for preparing the electrode of the platinum-carbon catalyst are easily available, and the equipment requirements for preparing the electrode are simple and easy to operate. The electrode of the platinum-carbon catalyst has excellent catalytic performance for the oxidation reaction of benzylic carbon-hydrogen bonds of aromatic compounds, good substrate adaptability, high oxygen utilization rate, excellent reaction conversion rate and selectivity, and the electrode is reusable. After multiple uses, the yield is still very high.

Description

Technical Field

[0001] The present invention relates to the technical field of electrode preparation and synthesis application, and in particular to the application of an electrode loaded with a platinum-carbon catalyst in the benzylic carbon-hydrogen bond oxidation reaction of an aromatic compound. Background Art

[0002] The benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds has been developed for decades and is a challenging and significant project. Aromatic side chain compounds such as benzylic aldehydes and ketones are widely used in pharmaceuticals, fine chemicals and other fields. Therefore, the synthesis of such compounds has always been a promising research project.

[0003] In recent years, the method for selective oxidation of benzylic carbon-hydrogen bonds is still mainly catalytic oxidation. Although a series of major advances have been made in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds in homogeneous catalytic systems such as transition metal catalytic systems (halogen salts, carboxylates, acetylacetonates of transition metals such as Co, Fe, and Mn) and some metal-free systems, the preparation steps of some photocatalysts are cumbersome and recyclability is difficult to achieve.

[0004] In heterogeneous systems, the use of oxidants is generally required, such as TBHP, NHPI, etc., and the benzylic carbon-hydrogen bond oxidation reaction is only applicable to a limited range of reaction substrates under visible light irradiation and oxygen atmosphere.

[0005] In electrochemical systems, it is generally necessary to add precious metal complexes such as ruthenium complexes, and non-precious metal complexes such as nickel diphosphine complexes, cobalt triphosphine complexes, and biomimetic iron complexes for electrocatalytic selective oxidation, and oxygen or water is used as the oxygen source. The direct utilization efficiency of oxygen in the air is low.

[0006] Therefore, the existing oxidative activation of the benzylic C-H bond of aromatic compounds usually requires the use of transition metal catalysis or the addition of stoichiometric oxidants and relatively harsh reaction conditions, such as high temperature, high oxygen pressure, and strong oxidants.

[0007] Therefore, improving the reaction efficiency and selectivity of the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, while reducing the preparation cost of the catalyst for the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, simplifying the preparation process, and improving the recyclability are technical problems that need to be solved urgently. Summary of the Invention

[0008] The purpose of the present invention is to provide an electrode loaded with platinum-carbon catalyst for use in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, thereby solving the problems of low efficiency and selectivity of the prior art benzylic carbon-hydrogen bond oxidation reaction, high preparation cost, complicated preparation steps, and inability to recycle the catalyst for the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds.

[0009] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0010] The present invention provides an application of an electrode loaded with a platinum-carbon catalyst in a benzylic carbon-hydrogen bond oxidation reaction of an aromatic compound.

[0011] Preferably, in the application of the above-mentioned platinum-carbon catalyst-supported electrode in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, the application method comprises the following steps:

[0012] Under a protective atmosphere, an aromatic compound, an electrolyte and a solvent are mixed, and an electrode loaded with a platinum-carbon catalyst is used as a cathode and a carbon rod is used as an anode to carry out an oxidation reaction to obtain an oxidation product.

[0013] Preferably, in the application of the above-mentioned platinum-carbon catalyst-supported electrode in the benzylic carbon-hydrogen bond oxidation reaction of an aromatic compound, the aromatic compound is a chain alkylbenzene with -CH2- at the benzylic position, 1,2,3,4-tetrahydronaphthalene, 1,2,3,4-tetrahydronaphthalene substituted product, indane, indane substituted product, fluorene, fluorene substituted product, 9,10-dihydroanthracene, 9,10-dihydroanthracene substituted product, xanthene or xanthene substituted product;

[0014] The structure of the chain alkylbenzene with -CH2- at the benzyl position is shown in Formula 1:

[0015]

[0016] Among them, R 1 is selected from hydrogen, methyl, ethyl, propyl or butyl; R 2 、R 3 、R 5 、R 6 R is independently selected from hydrogen or ethyl; 4 is selected from hydrogen, methyl, ethyl, a halogen atom or benzyl;

[0017] The 1,2,3,4-tetralin substituent is 5-methyl-1,2,3,4-tetralin, 5-amino-1,2,3,4-tetralin or 5-chloro-1,2,3,4-tetralin;

[0018] The indane substituent is 5-chloro-2,3-dihydro-1H-indene;

[0019] The fluorene substituent is 2-chlorofluorene or 2,7-dichlorofluorene;

[0020] The 9,10-dihydroanthracene substituent is 2-chloro-9,10-dihydroanthracene or 2,6-dimethyl-9,10-dihydroanthracene;

[0021] The xanthene substituent is 2-methylxanthene or 2,4-dimethylxanthene.

[0022] Preferably, in the application of the above-mentioned electrode loaded with platinum-carbon catalyst in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, the preparation method of the electrode loaded with platinum-carbon catalyst comprises the following steps:

[0023] The platinum-carbon catalyst is mixed with a Nafion solution to obtain a suspension, and the suspension is coated on an electrode to obtain an electrode loaded with the platinum-carbon catalyst.

[0024] Preferably, in the application of the above-mentioned electrode loaded with platinum-carbon catalyst in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, the content of platinum in the platinum-carbon catalyst is 10 to 60 wt%;

[0025] The concentration of the Nafion solution is 0.02-0.1 wt %.

[0026] Preferably, in the application of the above-mentioned platinum-carbon catalyst-loaded electrode in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, the amount ratio of the platinum-carbon catalyst to the Nafion solution is 0.1-10 mg: 500-2000 μL.

[0027] Preferably, in the application of the above-mentioned electrode loaded with platinum-carbon catalyst in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, drying is further included after the coating is completed.

[0028] Preferably, in the application of the above-mentioned platinum-carbon catalyst-supported electrode in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, the loading amount of the platinum-carbon catalyst in the platinum-carbon catalyst-supported electrode is 0.1 to 10 mg / 0.1 cm 3 .

[0029] Preferably, in the application of the above-mentioned platinum-carbon catalyst-supported electrode in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, the protective atmosphere is air or oxygen;

[0030] The electrolyte is tetrabutylammonium tetrafluoroborate;

[0031] The solvent is acetonitrile, dichloromethane, dichloroethane, acetone, methanol or ethanol;

[0032] The usage ratio of the aromatic compound, electrolyte and solvent is 0.1-2 mmol: 0.1-2 mmol: 3-10 mL.

[0033] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The electrode loaded with platinum-carbon catalyst provided by the present invention is used as the cathode of the electrochemical reaction. The prepared electrode can directly reduce and activate oxygen, so that the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds is carried out under mild conditions such as room temperature and air atmosphere. The electrode loaded with platinum-carbon catalyst is used for the benzylic carbon-hydrogen bond oxidation reaction of chain alkylbenzenes, and has excellent catalytic effect on the catalytic oxidation of benzylic aromatic compounds with electron-donating or electron-withdrawing substituents on the aromatic ring; it also has excellent catalytic effect on the benzylic oxidation reaction of cyclic aromatic compounds such as 1,2,3,4-tetrahydronaphthalene, indane, and fluorene. It has good substrate adaptability, high oxygen utilization rate, excellent reaction conversion rate and selectivity, and the electrode can be reused. After multiple uses, the yield is still very high.

[0035] (2) Currently, platinum-carbon catalyst materials are generally only used in the field of fuel cells and are rarely used in organic reactions. The present invention provides an application method of a loaded platinum-carbon catalyst electrode in electrochemical organic synthesis. The loaded platinum-carbon catalyst can directly utilize the cathode to activate oxygen in the air, thereby oxidizing the benzylic carbon-hydrogen bond of the aromatic compound.

[0036] (3) The preparation process of the electrode loaded with platinum-carbon catalyst in the present invention is simple and safe. At the same time, the raw materials for preparing the electrode loaded with platinum-carbon catalyst are easily available, the equipment required for preparing the electrode is simple, and the operation is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments or the prior art.

[0038] Figure 1 This is a scanning electron microscope characterization of the electrode loaded with platinum-carbon catalyst in Example 1;

[0039] Figure 2 This is an electron paramagnetic resonance spectrum of the superoxide radical anion generated by the reaction on the electrode of the platinum-carbon catalyst in Example 1. DETAILED DESCRIPTION

[0040] The present invention provides an application of an electrode loaded with a platinum-carbon catalyst in a benzylic carbon-hydrogen bond oxidation reaction of an aromatic compound.

[0041] In the present invention, the application method comprises the following steps:

[0042] Under a protective atmosphere, an aromatic compound, an electrolyte and a solvent are mixed, and an electrode loaded with a platinum-carbon catalyst is used as a cathode and a carbon rod is used as an anode to carry out an oxidation reaction to obtain an oxidation product.

[0043] In the present invention, the aromatic compound is preferably a chain alkylbenzene with -CH2- at the benzyl position, 1,2,3,4-tetralin, 1,2,3,4-tetralin substituted, indane, indane substituted, fluorene, fluorene substituted, 9,10-dihydroanthracene, 9,10-dihydroanthracene substituted, xanthene or xanthene substituted;

[0044] The structure of the chain alkylbenzene with -CH2- at the benzyl position is shown in Formula 1:

[0045]

[0046] Among them, R 1 is selected from hydrogen, methyl, ethyl, propyl or butyl; R 2 、R 3 、R 5 、R 6 R is independently selected from hydrogen or ethyl; 4 is selected from hydrogen, methyl, ethyl, a halogen atom or benzyl;

[0047] The 1,2,3,4-tetralin substituent is preferably 5-methyl-1,2,3,4-tetralin, 5-amino-1,2,3,4-tetralin or 5-chloro-1,2,3,4-tetralin;

[0048] The indane substituent is preferably 5-chloro-2,3-dihydro-1H-indene;

[0049] The fluorene substituent is preferably 2-chlorofluorene or 2,7-dichlorofluorene;

[0050] The 9,10-dihydroanthracene substituent is preferably 2-chloro-9,10-dihydroanthracene or 2,6-dimethyl-9,10-dihydroanthracene;

[0051] The xanthene substituent is preferably 2-methylxanthene or 2,4-dimethylxanthene.

[0052] In the present invention, the method for preparing the electrode loaded with platinum-carbon catalyst comprises the following steps:

[0053] The platinum-carbon catalyst is mixed with a Nafion solution to obtain a suspension, and the suspension is coated on an electrode to obtain an electrode loaded with the platinum-carbon catalyst.

[0054] In the present invention, the content of platinum in the platinum-carbon catalyst is preferably 10 to 60 wt %, more preferably 20 to 50 wt %, and even more preferably 40 wt %.

[0055] In the present invention, the platinum-carbon catalyst is a commercially available platinum-carbon catalyst.

[0056] In the present invention, the concentration of the Nafion solution is preferably 0.02 to 0.1 wt %, more preferably 0.04 to 0.08%, and even more preferably 0.05%.

[0057] In the present invention, the usage ratio of the platinum-carbon catalyst to the Nafion solution is preferably 0.1-10 mg:500-2000 μL, more preferably 0.5-5 mg:800-1500 μL, and even more preferably 1 mg:1000 μL.

[0058] In the present invention, the mixing temperature is 20-25°C, more preferably 21-24°C, more preferably 22-23°C; the mixing time is preferably 20-40 min, more preferably 25-35 min, more preferably 30 min.

[0059] In the present invention, the mixing method is preferably ultrasonic mixing.

[0060] In the present invention, the coating step further includes drying; the drying temperature is 50-65°C, more preferably 52-63°C, and even more preferably 55-60°C.

[0061] In the present invention, the electrode is preferably a graphite felt electrode.

[0062] In the present invention, the thickness of the graphite felt electrode is preferably 1 mm, and the size of the graphite felt electrode is preferably 1 cm×1 cm.

[0063] In the present invention, the loading amount of the platinum-carbon catalyst in the electrode loaded with the platinum-carbon catalyst is preferably 0.1 to 10 mg / 0.1 cm 3 , more preferably 2 to 8 mg / 0.1 cm 3 , more preferably 5 to 6 mg / 0.1 cm 3 .

[0064] In the present invention, the protective atmosphere is preferably air or oxygen, more preferably oxygen.

[0065] In the present invention, the electrolyte is preferably tetrabutylammonium tetrafluoroborate.

[0066] In the present invention, the solvent is preferably acetonitrile, dichloromethane, dichloroethane, acetone, methanol or ethanol.

[0067] In the present invention, the usage ratio of the aromatic compound, electrolyte and solvent is preferably 0.1-2 mmol:0.1-2 mmol:3-10 mL, more preferably 0.5-1 mmol:0.5-1 mmol:4-7 mL, and more preferably 0.5 mmol:0.5 mmol:5 mL.

[0068] In the present invention, the conditions of the oxidation reaction are: the temperature is preferably 20-25°C, more preferably 21-24°C, more preferably 22-23°C; the time is preferably 1-6h, more preferably 2-4h, more preferably 3h; the constant current is preferably 3-20mA, more preferably 6-14mA, more preferably 10mA.

[0069] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0070] In the following examples, the platinum-carbon catalyst was purchased from Suzhou Shengernuo Technology Co., Ltd., model number Premetek SPT40;

[0071] The Nafion solution was purchased from Beijing Yinuokai Technology Co., Ltd., model A40008.

[0072] Example 1

[0073] 1 mg of platinum carbon catalyst with a platinum content of 40 wt% was ultrasonically mixed with 1000 μL of Nafion solution with a concentration of 0.05 wt% at 25 ° C for 30 min to obtain a suspension. The suspension was coated on a graphite felt electrode with a size of 1 cm × 1 cm and a thickness of 1 mm, and dried at 60 ° C to obtain a platinum carbon catalyst loading of 1 mg / 0.1 cm 3 Electrode loaded with platinum-carbon catalyst.

[0074] Figure 1 The scanning electron microscopy characterization of the electrode loaded with platinum-carbon catalyst prepared in Example 1. Figure 1 It can be seen that the electrode loaded with platinum-carbon catalyst is a nanocluster structure.

[0075] Figure 2 This is the electron paramagnetic resonance spectrum of the superoxide radical anion generated by the electrode reaction of the supported platinum carbon catalyst in Example 1. Figure 2 It can be seen that the electrode loaded with platinum-carbon catalyst as the cathode can effectively reduce oxygen in the air to superoxide radical anions, thereby activating oxygen.

[0076] The platinum-carbon catalyst-loaded electrode prepared in Example 1 was applied to the benzylic carbon-hydrogen bond oxidation reaction of 1,2,3,4-tetralin. The reaction process was as follows:

[0077]

[0078] The method of application comprises the following steps:

[0079] Under air, a 25 mL three-necked reactor was charged with 0.5 mmol of 1,2,3,4-tetrahydronaphthalene, 0.5 mmol of tetrabutylammonium tetrafluoroborate (n-Bu4NBF4) as an electrolyte, a carbon rod as an anode, the platinum-carbon catalyst-supported electrode prepared in Example 1 as a cathode, and 5 mL of acetonitrile as a solvent. The reaction was left open at 10 mA and 25°C for 3 h. After completion of the reaction, the resulting mixture was analyzed by high-performance liquid chromatography (HPLC) using a wavelength of 210 nm and a mobile phase ratio of V (acetonitrile):V (deionized water) of 50:50. Testing revealed a conversion of 95%, a selectivity of 95%, and a yield of 90%.

[0080] Example 2

[0081] 1 mg of platinum carbon catalyst with a platinum content of 10 wt% was ultrasonically mixed with 1000 μL of Nafion solution with a concentration of 0.05 wt% at 25 ° C for 30 min to obtain a suspension. The suspension was coated on a graphite felt electrode with a size of 1 cm × 1 cm and a thickness of 1 mm, and dried at 60 ° C to obtain a platinum carbon catalyst loading of 1 mg / 0.1 cm 3 Electrode loaded with platinum-carbon catalyst.

[0082] The platinum-carbon catalyst-loaded electrode prepared in Example 2 was applied to the benzylic carbon-hydrogen bond oxidation reaction of 1,2,3,4-tetralin. The reaction process was as follows:

[0083]

[0084] The method of application comprises the following steps:

[0085] Under air, a 25 mL three-necked reactor was charged with 0.5 mmol of 1,2,3,4-tetrahydronaphthalene, 0.5 mmol of tetrabutylammonium tetrafluoroborate (n-Bu4NBF4) as an electrolyte, a carbon rod as an anode, the platinum-carbon catalyst-supported electrode prepared in Example 2 as a cathode, and 5 mL of acetonitrile as a solvent. The reaction was left open at 10 mA and 25°C for 3 h. After completion of the reaction, the resulting mixture was analyzed by high-performance liquid chromatography (HPLC) using a wavelength of 210 nm and a mobile phase ratio of V (acetonitrile):V (deionized water) of 50:50. The reaction showed a conversion of 85%, a selectivity of 90%, and a yield of 77%.

[0086] Example 3

[0087] 1 mg of platinum carbon catalyst with a platinum content of 20 wt% was ultrasonically mixed with 1000 μL of Nafion solution with a concentration of 0.05 wt% at 25 ° C for 30 min to obtain a suspension. The suspension was coated on a graphite felt electrode with a size of 1 cm × 1 cm and a thickness of 1 mm, and dried at 60 ° C to obtain a platinum carbon catalyst loading of 1 mg / 0.1 cm 3 Electrode loaded with platinum-carbon catalyst.

[0088] The platinum-carbon catalyst-loaded electrode prepared in Example 3 was applied to the benzylic carbon-hydrogen bond oxidation reaction of 1,2,3,4-tetralin. The reaction process was as follows:

[0089]

[0090] The method of application comprises the following steps:

[0091] Under air, a 25 mL three-necked reactor was charged with 0.5 mmol of 1,2,3,4-tetrahydronaphthalene, 0.5 mmol of tetrabutylammonium tetrafluoroborate (n-Bu4NBF4) as an electrolyte, a carbon rod as an anode, the platinum-carbon catalyst-supported electrode prepared in Example 3 as a cathode, and 5 mL of acetonitrile as a solvent. The reaction was left open at 10 mA and 25°C for 3 h. After completion of the reaction, the resulting mixture was analyzed by high-performance liquid chromatography (HPLC) using a wavelength of 210 nm and a mobile phase ratio of V (acetonitrile):V (deionized water) of 50:50. The reaction showed a conversion of 87%, a selectivity of 92%, and a yield of 80%.

[0092] Example 4

[0093] 1 mg of platinum carbon catalyst with a platinum content of 60 wt% was ultrasonically mixed with 1000 μL of Nafion solution with a concentration of 0.05 wt% at 25 ° C for 30 min to obtain a suspension. The suspension was coated on a graphite felt electrode with a size of 1 cm × 1 cm and a thickness of 1 mm, and dried at 60 ° C to obtain a platinum carbon catalyst loading of 1 mg / 0.1 cm 3 Electrode loaded with platinum-carbon catalyst.

[0094] The platinum-carbon catalyst-loaded electrode prepared in Example 4 was applied to the benzylic carbon-hydrogen bond oxidation reaction of 1,2,3,4-tetralin. The reaction process was as follows:

[0095]

[0096] The method of application comprises the following steps:

[0097] Under air, a 25 mL three-necked reactor was charged with 0.5 mmol of 1,2,3,4-tetrahydronaphthalene, 0.5 mmol of tetrabutylammonium tetrafluoroborate (n-Bu4NBF4) as an electrolyte, a carbon rod as an anode, the platinum-carbon catalyst-supported electrode prepared in Example 4 as a cathode, and 5 mL of acetonitrile as a solvent. The reaction was left open at 10 mA and 25°C for 3 h. After completion of the reaction, the resulting mixture was analyzed by high-performance liquid chromatography (HPLC) using a wavelength of 210 nm and a mobile phase ratio of V (acetonitrile):V (deionized water) of 50:50. The reaction conversion, selectivity, and yield were 96%, 95%, and 91%, respectively.

[0098] Example 5

[0099] The electrode loaded with platinum-carbon catalyst prepared in Example 1 was applied to the benzylic carbon-hydrogen bond oxidation reaction of 1,2,3,4-tetralin. The application method was the same as that in Example 1, except that tetrabutylammonium hexafluorophosphate (n-Bu4NPF6), tetrabutylammonium acetate (n-Bu4N(OAc)2), tetrabutylammonium perchlorate (n-Bu4NClO4), LiBr, and LiClO4 were used as electrolytes, respectively. The reaction results are shown in Table 1.

[0100] Table 1 Reaction results in Example 5

[0101] electrolytes Selectivity (%) Conversion rate (%) Yield (%) <![CDATA[n-Bu4NPF6]]> 93 83 77 <![CDATA[n-Bu4N(OAc)2]]> 87 75 65 <![CDATA[n-Bu4NClO4]]> 91 77 70 LiBr 91 33 30 <![CDATA[LiClO4]]> 93 68 63

[0102] Example 6

[0103] The platinum-carbon catalyst-loaded electrode prepared in Example 1 was applied to the benzylic carbon-hydrogen bond oxidation reaction of 1,2,3,4-tetralin. The reaction process was as follows:

[0104]

[0105] The method used was the same as that in Example 1, except that dichloromethane (DCM), dichloroethane (DCE), acetone (Acetone), methanol (MeOH), and ethanol (EtOH) were used as solvents, respectively. The reaction results are shown in Table 2.

[0106] Table 2 Reaction results in Example 6

[0107] electrolytes Selectivity (%) Conversion rate (%) Yield (%) DCM 93 31 29 DCE 94 24 23 Acetone 93 61 57 MeOH 95 38 36 EtOH 97 80 78

[0108] Example 7

[0109] Different electrodes were applied to the benzylic carbon-hydrogen bond oxidation reaction of 1,2,3,4-tetralin. The application method was consistent with that in Example 1, except that: a carbon rod was used as the anode and platinum was used as the cathode (C(+)|Pt(-)); a carbon rod was used as the anode and a carbon rod was used as the cathode (C(+)|C(-)); a carbon rod was used as the anode and a nickel was used as the cathode (C(+)|Ni(-)); platinum was used as the anode and the electrode loaded with the platinum-carbon catalyst prepared in Example 1 was used as the cathode (Pt(+)|Pt / C(-)); platinum was used as the anode and a platinum was used as the cathode (Pt(+)|Pt(-)); the reaction results are shown in Table 3.

[0110] Table 3 Reaction results in Example 7

[0111] electrode Selectivity (%) Conversion rate (%) Yield (%) C(+)|Pt(-) 98 28 27 C(+)|C(-) 86 43 37 C(+)|Ni(-) 90 56 50 Pt(+)|Pt / C(-) 82 75 62 Pt(+)|Pt(-) 79 21 17

[0112] Example 8

[0113] The platinum-carbon catalyst-loaded electrode prepared in Example 1 was applied to the benzylic carbon-hydrogen bond oxidation reaction of 1,2,3,4-tetralin. The application method was the same as that in Example 1, except that N2 and O2 were used as the protective atmosphere, respectively. The reaction results are shown in Table 4.

[0114] Table 4 Reaction results in Example 8

[0115] Protective atmosphere Selectivity (%) Conversion rate (%) Yield (%) <![CDATA[N2]]> 0 0 0 <![CDATA[O2]]> 95 96 91

[0116] Example 9

[0117] The platinum-carbon catalyst-loaded electrode prepared in Example 1 was applied to the benzylic carbon-hydrogen bond oxidation reaction of 1,2,3,4-tetralin. The application method was the same as that in Example 1, except that the constant current was changed to 5 mA and 20 mA. The reaction results are shown in Table 5.

[0118] Table 5 Reaction results in Example 9

[0119] Constant current Selectivity (%) Conversion rate (%) Yield (%) 5mA 93 27 25 20mA 83 60 50

[0120] Example 10

[0121] The platinum-carbon catalyst-loaded electrode prepared in Example 1 was applied to the benzylic carbon-hydrogen bond oxidation reaction of 1,2,3,4-tetralin. The application method was the same as that in Example 1, except that the reaction time was changed to 1.5 h, 6 h, and 12 h. The reaction results are shown in Table 6.

[0122] Table 6 Reaction results in Example 10

[0123] Reaction time Selectivity (%) Conversion rate (%) Yield (%) 1.5h 93 58 54 6h 88 75 66 12h 75 70 53

[0124] Example 11

[0125] The platinum-carbon catalyst-loaded electrode prepared in Example 1 was applied to the benzylic carbon-hydrogen bond oxidation reaction of 1,2,3,4-tetralin. The application method was the same as that in Example 1, except that the reaction was repeated 5 times using the platinum-carbon catalyst-loaded electrode prepared in Example 1. The reaction results are shown in Table 7.

[0126] Table 7 Reaction results in Example 11

[0127]

[0128]

[0129] Example 12

[0130] The electrode loaded with platinum-carbon catalyst prepared in Example 1 was applied to the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds. The application method was the same as that in Example 1, except that the aromatic compound was changed.

[0131] The yields of different aromatic compounds are as follows:

[0132] The aromatic compound is ethylbenzene, and the product is The yield is 90%;

[0133] The aryl compound is 4-ethyltoluene, and the product is The yield was 69%;

[0134] The aryl compound is 1,4-diethylbenzene, and the product is The yield was 82%;

[0135] The aryl compound is 1-bromo-4-ethylbenzene, and the product is The yield was 74%;

[0136] The aryl compound is 1-chloro-4-ethylbenzene, and the product is The yield was 82%;

[0137] The aromatic compound is propylbenzene, and the product is The yield was 81%;

[0138] The aromatic compound is n-butylbenzene, and the product is The yield is 77%;

[0139] The aryl compound is pentylbenzene, and the product is The yield was 67%;

[0140] The aryl compound is 1,2-diethylbenzene and the product is The yield is 75%;

[0141] The aryl compound is 1,3,5-triethylbenzene and the product is The yield is 65%;

[0142] The aryl compound is diphenylmethane, and the product is The yield is 77%;

[0143] The aryl compound is 5-methyl-1,2,3,4-tetrahydronaphthalene, and the product is The yield is 70%; the aromatic compound is 5-amino-1,2,3,4-tetrahydronaphthalene, and the product is The yield is 69%; the aromatic compound is 5-chloro-1,2,3,4-tetrahydronaphthalene, and the product is The yield is 75%; the aromatic compound is indane, and the product is The yield was 89%;

[0144] The aryl compound is 5-chloro-2,3-dihydro-1H-indene, and the product is The yield is 80%; the aromatic compound is fluorene, and the product is The yield was 81%;

[0145] The aromatic compound is 2-chlorofluorene, and the product is The yield is 75%;

[0146] The aromatic compound is 2,7-dichlorofluorene, and the product is The yield is 75%;

[0147] The aryl compound is 9,10-dihydroanthracene, and the product is The yield is 80%;

[0148] The aryl compound is 2-chloro-9,10-dihydroanthracene, and the product is The yield is 78%;

[0149] The aryl compound is 2,6-dimethyl-9,10-dihydroanthracene, and the product is The yield is 75%;

[0150] The aryl compound is xanthene, and the product is The yield is 77%;

[0151] The aromatic compound is 2-methylxanthene, and the product is The yield was 72%;

[0152] The aromatic compound is 2,4-dimethylxanthene, and the product is The yield was 73%;

[0153] The aryl compound is 4-ethylbiphenyl, and the product is The yield is 45%;

[0154] The aryl compound is 4-n-propylbiphenyl, and the product is The yield was 41%;

[0155] The aryl compound is 4-bromo-4'-ethylbiphenyl, and the product is The yield is 44%;

[0156] The aryl compound is 2-ethylnaphthalene, and the product is The yield is 50%;

[0157] The aryl compound is toluene, and the product is The yield was 89%;

[0158] The aromatic compound is 1,4-dimethylbenzene, and the product is The yield is 84%;

[0159] The aromatic compound is mesitylene, and the product is The yield was 81%.

[0160] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. Application of a platinum-carbon catalyst-supported electrode in the benzylic carbon-hydrogen bond oxidation reaction of an aromatic compound, characterized in that: The application method comprises the following steps: Under a protective atmosphere, an aromatic compound, an electrolyte and a solvent are mixed, and an electrode loaded with a platinum-carbon catalyst is used as a cathode and a carbon rod is used as an anode to carry out an oxidation reaction to obtain an oxidation product; The aromatic compound is a chain alkylbenzene with -CH2- at the benzyl position, 1,2,3,4-tetralin, 1,2,3,4-tetralin substituted, indane, indane substituted, fluorene, fluorene substituted, 9,10-dihydroanthracene, 9,10-dihydroanthracene substituted, xanthene or xanthene substituted; the structure of the chain alkylbenzene with -CH2- at the benzyl position is as shown in Formula 1: Among them, R 1 is selected from hydrogen, methyl, ethyl, propyl or butyl; R 2 、R 3 、R 5 、R 6 R is independently selected from hydrogen or ethyl; 4 is selected from hydrogen, methyl, ethyl, a halogen atom or benzyl; The 1,2,3,4-tetralin substituent is 5-methyl-1,2,3,4-tetralin, 5-amino-1,2,3,4-tetralin or 5-chloro-1,2,3,4-tetralin; The indane substituent is 5-chloro-2,3-dihydro-1H-indene; The fluorene substituent is 2-chlorofluorene or 2,7-dichlorofluorene; The 9,10-dihydroanthracene substituent is 2-chloro-9,10-dihydroanthracene or 2,6-dimethyl-9,10-dihydroanthracene; The xanthene substituent is 2-methylxanthene or 2,4-dimethylxanthene; The protective atmosphere is air or oxygen; The electrolyte is tetrabutylammonium tetrafluoroborate; The solvent is acetonitrile or ethanol; The ratio of the aromatic compound, electrolyte and solvent is 0.1-2 mmol: 0.1-2 mmol: 3-10 mL; The constant current of the oxidation reaction is 10-14 mA.

2. Use of the platinum-carbon catalyst-supported electrode according to claim 1 in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, characterized in that: The method for preparing the electrode loaded with platinum-carbon catalyst comprises the following steps: The platinum-carbon catalyst is mixed with a Nafion solution to obtain a suspension, and the suspension is coated on an electrode to obtain an electrode loaded with the platinum-carbon catalyst.

3. Use of the platinum-carbon catalyst-supported electrode according to claim 2 in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, characterized in that: The platinum content in the platinum-carbon catalyst is 10 to 60 wt%; The concentration of the Nafion solution is 0.02-0.1 wt %.

4. Use of the platinum-carbon catalyst-supported electrode according to claim 2 in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, characterized in that: The usage ratio of the platinum-carbon catalyst to the Nafion solution is 0.1-10 mg: 500-2000 μL.

5. Use of the platinum-carbon catalyst-supported electrode according to claim 3 in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, characterized in that: The coating process further includes drying.

6. Use of the platinum-carbon catalyst-supported electrode according to claim 3 or 4 in the benzylic carbon-hydrogen bond oxidation reaction of aromatic compounds, characterized in that: The loading amount of the platinum-carbon catalyst in the electrode loaded with the platinum-carbon catalyst is 0.1 to 10 mg / 0.1 cm 3 .

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