A method for preparing carbonyl compounds

Abstract

This application discloses a method for preparing carbonyl compounds. The method includes: reacting a mixture containing alcohols or hydrocarbons, acidic compounds, and solvents under an oxygen-containing atmosphere with light irradiation to obtain the carbonyl compounds. This method has advantages such as high yield, high atom economy, environmental friendliness, no transition metal involvement, mild reaction conditions, and simple and convenient post-processing.

Description

Technical Field

[0001] This application relates to a method for preparing carbonyl compounds, belonging to the field of organic synthesis technology. Background Technology

[0002] Aldehydes / ketones, especially aldehydes, have wide applications in fragrance and pharmaceutical synthesis, natural product synthesis, and new material preparation. The green and mild synthesis of aldehydes / ketones through photo-driven activation of CH bonds is particularly favored.

[0003] The global benzaldehyde market is experiencing growth. my country has a large demand for benzaldehyde, with annual consumption growing at a rate of 7%. In particular, the demand for high-quality, chlorine-free benzaldehyde has increased significantly, accounting for 47% of total demand.

[0004] Traditional production routes for benzaldehyde compounds involve chlorination and hydrolysis of the toluene side chain or liquid-phase oxidation of toluene. These methods involve numerous reaction steps, demanding conditions, low atom utilization, and a large number of additional reagents and byproducts, failing to meet the demands of sustainable green chemical industry development. In recent years, photocatalytic oxidation of hydrocarbons such as toluene or alcohols to prepare aldehydes / ketones has opened up a green and sustainable route, attracting significant attention from researchers. A 2014 report described the photocatalytic selective oxidation of toluene using ruthenium-supported TiO2, exhibiting a high benzaldehyde selectivity of 89% (Angew Chem, 2014, 126:12813-12816), but this requires the use of the precious metal ruthenium. Cao et al. developed a photochromic composite photocatalyst, Bi2WO3... 6-x BiOCl selectively oxidizes toluene, achieving near 100% conversion, but the selectivity for benzaldehyde is only 30% (Nat Catal, 2018, 1:704-710). In 2022, a method for the selective oxidation of 4-methylbiphenyl to 4-formaldehyde biphenyl using an alkali metal-modified carbon nitride photocatalyst was reported (CN115353446A). Therefore, developing novel methods for the direct photocatalytic activation of CH bonds to prepare aldehyde compounds with high selectivity and high conversion remains a research hotspot in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art by providing a method for synthesizing aldehyde / ketone compounds with high activity and high selectivity by using light (visible light) as the driving force of the reaction, directly activating CH bonds through the in-situ generation of highly active free radical intermediates, and using oxygen as an oxidant.

[0006] According to one aspect of this application, a method for preparing a carbonyl compound is provided, the method comprising:

[0007] In an oxygen-containing atmosphere, a mixture containing alcohols or hydrocarbons, acidic compounds, and solvents is reacted by light irradiation to obtain the carbonyl compounds.

[0008] The alcohols or hydrocarbons, acidic compounds, solvents, and oxygen-containing atmosphere spontaneously form a reaction catalyst.

[0009] The alcohol or hydrocarbon is selected from one of Formula I-1, Formula I-2, and Formula I-3;

[0010]

[0011] The carbonyl compound is selected from one of formula II-1, formula II-2, and formula II-3;

[0012]

[0013] In Equations I-1 and II-1, R 1 R 2 Independently selected from hydrogen, halogen, nitro, cyano, trifluoromethyl, C1-C 10 Alkyl groups, C1-C 10 Substituted alkyl groups, C6-C 10 aryl, C4-C 10 One of the heteroaryl groups;

[0014] In Equations I-2 and II-2, R 3 R 4 Independently selected from hydrogen, C1 to C 10 Alkyl groups, C1-C 10 One of the substituted alkyl groups;

[0015] The substituents of the substituted alkyl group are selected from C6 to C6. 10 One of the aryl groups;

[0016] In Equations I-3 and II-3, R 5 Independently selected from C1 to C 10 Alkyl groups, C6-C 10 aryl, C6-C 10 One of the substituted aryl groups;

[0017] The substituents in the substituted aryl group are selected from one of halogen, nitro, and cyano groups.

[0018] Optionally, the carbonyl compound is selected from benzaldehyde, 4-fluorobenzaldehyde, 2-bromobenzaldehyde, 4-iodobenzaldehyde, 4-nitrobenzaldehyde, 4-trifluoromethylbenzaldehyde, 3-cyanobenzaldehyde, 4-cyanobenzaldehyde, 4-carboxybenzaldehyde, 4-carboxylic acid methyl ester benzaldehyde, 4-tert-butylbenzaldehyde, 4-phenylbenzaldehyde, 3,5-dinitrobenzaldehyde, 3,4,5-trimethoxybenzaldehyde, pentafluorobenzaldehyde, naphthaldehyde, pyrene formaldehyde, furanaldehyde, benzofuran-2-carboxaldehyde, benzothiazole-2-carboxaldehyde, p-dibenzoaldehyde, benzophenone, 4-chlorobenzophenone, 4,4-dicyanobenzophenone. Ketone, 2,2-diphenyldione, acetophenone, cyclohexanone, cyclooctanone, p-methylbenzaldehyde, p-fluorobenzaldehyde, p-chlorobenzaldehyde, p-bromobenzaldehyde, n-hexanol, or one of the structures shown in 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, 2l, 2m, 2n, 2o, 2p, 2q, 2r, 2s, 2t, 2u, 2v, 2w, 2x, 2y, 2z, 2aa, 2ab, 2ac, 2ad, 2ae, 2af, 2ag, 2ah, 2ai, 2aj, 2ak, 2al, 2am, 2an, 2ao, 2ap, 2aq, 2ar, 2as;

[0019]

[0020]

[0021] Optionally, the molar ratio of the acidic compound, alcohol or hydrocarbon, and solvent is 1:(1-10):(1-10000).

[0022] Optionally, the molar ratio of the acidic compound, alcohol or hydrocarbon, and solvent is selected from any value in 1:(1-10):(1-10000), 1:(2-10):(200-10000), 1:(3-10):(500-10000), 1:(4-10):(1000-10000), 1:(5-10):(5000-10000), 1:(6-10):(6000-10000), 1:(7-10):(7000-10000), 1:(4-7):(5000-7000) or a range between any two of the above.

[0023] Optionally, the molar ratio of the acidic compound, alcohol or hydrocarbon, and solvent is 1:(4-7):(5000-7000).

[0024] Optionally, the acidic compound is selected from at least one of hydrochloric acid, sulfuric acid, hydrobromic acid, phosphoric acid, acetic acid, and hydroiodic acid.

[0025] Optionally, the solvent is selected from at least one of cyclohexane, dichloromethane, ethyl acetate, acetone, acetonitrile, tetrahydrofuran, water, toluene, anisole, 1,4-dioxane, dibutyl ether, and diphenyl ether.

[0026] Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere is 20% to 100%.

[0027] Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere is selected from any value of 20%, 30%, 50%, 70%, 90%, 100%, or a range between any two of the above.

[0028] Optionally, the reaction temperature is 20–50°C.

[0029] Optionally, the temperature of the reaction is selected from any value of 20°C, 25°C, 30°C, 35°C, 40°C, 50°C, or a range between any two of the above.

[0030] Optionally, the reaction time is 0.15 to 8 hours.

[0031] Optionally, the reaction time is selected from any value of 0.15h, 1h, 2h, 3h, 5h, 7h, 8h or a range between any two of the above.

[0032] This application is achieved through the following technical solution:

[0033] A method for photocatalytic preparation of aldehyde / ketone compounds includes the following steps:

[0034] (1) Acid, solvent, oxygen and reactants are mixed and stirred to form a complex, i.e., a reaction catalyst. The condition for the formation of this complex is that there are intermolecular interactions such as hydrogen bonds or electrostatic attraction between the acid, solvent and reactants, which is also the key to improving the selectivity of the reaction products.

[0035] (2) The reaction was carried out under light-driven aerobic environment and the reaction was tracked and detected by thin-layer chromatography.

[0036] (3) After the reaction is complete, the target product is obtained by rotary evaporation with an organic solvent to remove the organic solvent.

[0037] A light-driven selective oxidation method for preparing aldehydes / ketones from alcohols or hydrocarbons such as xylene. An acid, solvent, oxygen, and reactants are mixed and spontaneously form a complex, i.e., a reaction catalyst, under light (visible light) driving. This complex can selectively oxidize hydrocarbons such as xylene or alcohols to aldehydes / ketones.

[0038] In this application, a complex is formed in situ via light-driven synthesis to generate bromine radicals and superoxide radical anions. The bromine radicals abstract hydrogen atoms from the CH bond to form carbon-centered radicals. Then, the superoxide radical anions combine with the carbon-centered radicals to form peroxide intermediates. Finally, a molar water is removed to form the target product, an aldehyde / ketone. This method has advantages such as high yield, high atom economy, environmental friendliness, no transition metal involvement, mild reaction conditions, and simple and convenient post-processing.

[0039] In this application, C1 to C 10 C6~C 10 "etc." refers to the number of carbon atoms contained in the group.

[0040] In this application, the term "alkyl" refers to a group formed by the loss of any one hydrogen atom from an alkane molecule.

[0041] In this application, the term "aryl" refers to a group formed by the loss of a hydrogen atom from an aromatic ring in an aromatic compound molecule; for example, p-tolyl formed by the loss of a hydrogen atom at the para-position of the methyl group on the benzene ring of toluene.

[0042] In this application, "substituted alkyl" and "substituted aryl" refer to alkyl groups substituted by any group and aromatic groups substituted by any group, respectively.

[0043] The beneficial effects that this application can produce include:

[0044] 1) The synthesis method provided in this application avoids the use of stoichiometric oxidants or precious metals. Under light-driven conditions, the oxygen-to-target product aldehyde / ketone of alcohols or hydrocarbons can be prepared at room temperature. This method is simple, easy to implement, mild, and safe to operate.

[0045] 2) The method provided in this application has the advantages of being green and environmentally friendly, having high atom economy, simple and convenient post-processing, and being suitable for large-scale production, which can make the synthesis of aldehyde / ketone compounds more green and reduce synthesis costs. Attached Figure Description

[0046] Figure 1 Screening of benzyl alcohol in Examples 1 and 2 of this application for different types and amounts of acid (Figure a shows the reaction performance of different halogen acids in ethyl acetate (EA); Figure b shows the relationship between reaction performance and HBr concentration in EA).

[0047] Figure 2 The screening of benzyl alcohol in Examples 3 and 4 of this application in different types of solvents (Figure a shows the reactivity in various solvents; Figure b shows the reactivity in different ester solvents (EA: ethyl acetate, MP: methyl propionate; EP: ethyl propionate)).

[0048] Figure 3 Figure 1 shows the Tyndall effect experiment of 1-pyrene methanol in this application and the possible structural diagram of the complex (Figure 2a shows the Tyndall effect experiment; Figure 3b shows the structural diagram of the microemulsion particles and the self-assembled complex (PM: 1-pyrene methanol; EA: ethyl acetate)). Detailed Implementation

[0049] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0050] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0051] In the embodiments of this application, a Varian I NOVA 400MHz nuclear magnetic resonance spectrometer from Varian Scientific, Inc. was used to perform qualitative analysis on the products.

[0052] The yield of the target product in this application was calculated using the following method:

[0053] Yield of the target product = (actual mass of the target product / theoretical mass of the target product) × 100%.

[0054] Screening Example 1: The Effect of Different Types of Hydrohalic Acids on Carbonyl Compounds

[0055] like Figure 1 As shown in Figure a, benzyl alcohol 1a was selected as the template substrate, and different types of hydrohalic acids were first investigated. Figure 1 a) Experimental studies revealed that the amount of benzaldehyde (BAL) produced by the photo-oxidation of benzyl alcohol (BA) in the presence of 20 mol% hydrochloric acid (HCl) was negligible. Interestingly, the selectivity for BAL exceeded 97% when using HBr or HI, and the conversion rate of BA reached 93% in the presence of 20 mol% HBr, significantly higher than the 18% conversion rate obtained using 20 mol% HI in EA solvent. These experimental results indicate that the photo-oxidation activity of BA depends on the halogen acid used, and HBr exhibited the best reactivity among the three hydrogen halides used in the experiments.

[0056] Screening Example 2: The Effect of Hydrobromic Acid Dosage on Carbonyl Compounds

[0057] like Figure 1As shown in Figure b, the effect of the amount of HBr on the reactivity of benzyl alcohol was investigated. As the HBr concentration decreased from 20 mol% to 5 mol%, the conversion rate of BA decreased from 93% to 42%, while the selectivity for BAL increased from 97% to 99%. When the HBr concentration increased from 20 mol% to 40 mol%, the conversion rate of BA remained high (approximately 95%), but the selectivity for BAL decreased to 36%. Figure 1 b). These results indicate that the reaction performance is also affected by the HBr concentration.

[0058] Screening Example 3: The Effect of Different Types of Solvents on Carbonyl Compounds

[0059] like Figure 2 As shown in Figure a, the effect of solvents on the photooxidation of alcohols was screened by using CH3CN, EA, CH3COCH3, CH2Cl2 and H2O as solvents. Figure 2 The results show that high conversion (93%) and selectivity (97%) can be obtained when using ethyl acetate (EA) as a solvent. With CH3CN as a solvent, the conversion of benzyl alcohol (BA) decreases to 26%, but the selectivity for benzaldehyde (BAL) remains as high as 98%. Under otherwise identical conditions, the photooxidation of BA essentially does not occur when using CH3COCH3, CH2Cl2, and H2O as solvents. These experimental results indicate that the solvent has a significant impact on the photooxidation of alcohols.

[0060] Screening Example 4: The Effect of Different Types of Ester Solvents on Carbonyl Compounds

[0061] like Figure 2 As shown in Figure b, it can be seen from screening example 3 that ethyl acetate solvent is favorable for the photo-oxidation of alcohol reaction process, and other similar ester solvents were screened. Figure 2 b shows that when methyl propionate (MP) and ethyl propionate (EP) are used as solvents, the conversion rate of BA is 93%-99%, and it has high selectivity for BAL (92%-97%), which indicates that low carbon ester solvents are favorable for the photo-oxidation reaction performance of BA.

[0062] Example 1: Preparation of Benzaldehyde

[0063] In a transparent quartz bottle equipped with a rubber stopper and a magnetic stir bar, benzyl alcohol (0.2 mmol) and 20 mol% hydrobromic acid were added to 12 mL of reaction solvent. The reaction mixture was stirred under light irradiation in an oxygen atmosphere at ambient temperature. The reaction progress was monitored by GC or TLC during the reaction. After reacting for 0.15 h at room temperature, the solvent was removed by vacuum or extraction. The residue was purified by column chromatography with petroleum ether / ethanol to obtain the desired product, benzaldehyde. The yield of the target product was 90%.

[0064] Example 2 Preparation of benzaldehyde

[0065] Under the same reaction conditions as in Example 1, only the reaction solvent was changed to acetonitrile, and the yield of the target product was 25%.

[0066] Example 3: Preparation of Benzaldehyde

[0067] Under the same reaction conditions as in Example 1, only the reaction solvent was changed to dichloromethane. The yield of the target product was 0%.

[0068] Example 4: Preparation of 4-fluoro-benzaldehyde

[0069] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by 4-fluoro-benzyl alcohol, the yield of the target product was 92%.

[0070] Example 5: Preparation of 2-bromo-benzaldehyde

[0071] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by 2-bromo-benzyl alcohol, the yield of the target product was 86%.

[0072] Example 6: Preparation of 4-iodo-benzaldehyde

[0073] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by 4-iodo-benzyl alcohol, the yield of the target product was 90%.

[0074] Example 7 Preparation of 4-Nitro-Benzaldehyde

[0075] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by 4-nitro-benzyl alcohol, the yield of the target product was 90%.

[0076] Example 8: Preparation of 4-trifluoromethyl-benzaldehyde

[0077] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by 4-trifluoromethyl-benzyl alcohol, the yield of the target product was 92%.

[0078] Example 9: Preparation of 3-cyano-benzaldehyde

[0079] Under the same reaction conditions as in Example 1, but with the substrate benzyl alcohol replaced by 3-cyano-benzyl alcohol, the yield of the target product was 88%.

[0080] Example 10: Preparation of 4-cyano-benzaldehyde

[0081] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by 4-cyano-benzyl alcohol, the yield of the target product was 93%.

[0082] Example 11 Preparation of 4-Carboxy-Benzaldehyde

[0083] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by 4-carboxy-benzyl alcohol, the yield of the target product was 87%.

[0084] Example 12 Preparation of 4-carboxylic acid methyl ester-benzaldehyde

[0085] Under the same reaction conditions as in Example 1, but with the substrate benzyl alcohol replaced by methyl 4-carboxylate-benzyl alcohol, the yield of the target product was 87%.

[0086] Example 13 Preparation of 4-tert-butylbenzaldehyde

[0087] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by 4-tert-butylbenzyl alcohol, the yield of the target product was 81%.

[0088] Example 14 Preparation of 4-Phenylacetaldehyde

[0089] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by 4-phenyl-benzyl alcohol, the yield of the target product was 81%.

[0090] Example 15 Preparation of 3,5-dinitrobenzaldehyde

[0091] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by 3,5-dinitro-benzyl alcohol, the yield of the target product was 73%.

[0092] Example 16 Preparation of 3,4,5-trimethoxy-benzaldehyde

[0093] Under the same reaction conditions as in Example 1, but with the substrate benzyl alcohol replaced by 3,4,5-trimethoxy-benzyl alcohol, the yield of the target product was 63%.

[0094] Example 17 Preparation of pentafluorobenzaldehyde

[0095] Under the same reaction conditions as in Example 1, but with the substrate benzyl alcohol replaced by pentafluoro-benzyl alcohol, the yield of the target product was 76%.

[0096] Example 18 Preparation of Naphthaldehyde

[0097] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by naphthaleneethanol, the yield of the target product was 86%.

[0098] Example 19 Preparation of Pyrene-Formaldehyde

[0099] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by pyrene methanol, the yield of the target product was 82%.

[0100] Example 20: Preparation of furanaldehyde

[0101] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by furanyl alcohol, the yield of the target product was 56%.

[0102] Example 21 Preparation of benzofuran-2-carboxaldehyde

[0103] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by benzofuran-2-methanol, the yield of the target product was 82%.

[0104] Example 22 Preparation of benzothiazole-2-formaldehyde

[0105] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by benzothiazole-2-methanol, the yield of the target product was 77%.

[0106] Example 23 Preparation of benzothiazole-2-formaldehyde

[0107] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by benzothiazole-2-methanol, the yield of the target product was 77%.

[0108] Example 24 Preparation of p-diphenylformaldehyde

[0109] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by p-diphenylethanol, the yield of the target product was 72%.

[0110] Example 25 Preparation of Triphenylformaldehyde

[0111] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by triphenylethanol, the yield of the target product was 62%.

[0112] Example 26 Preparation of benzophenone

[0113] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by dibenzyl alcohol, the yield of the target product was 96%.

[0114] Example 27 Preparation of 4-chlorobenzophenone

[0115] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by 4-chlorodiphenylethanol, the yield of the target product was 95%.

[0116] Example 28 Preparation of 4,4-dicyanobenzophenone

[0117] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by 4,4-dicyanodiphenylethanol, the yield of the target product was 95%.

[0118] Example 29 Preparation of 2,2-Diphenyldione

[0119] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by 2,2-diphenyl glycol, the yield of the target product was 93%.

[0120] Example 30 Preparation of acetophenone

[0121] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by phenylethanol, the yield of the target product was 65%.

[0122] Example 31 Preparation of Cyclohexanone

[0123] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by cyclohexanol, the yield of the target product was 51%.

[0124] Example 31 Preparation of Cyclooctanone

[0125] Under the same reaction conditions as in Example 1, but with benzyl alcohol replaced by cyclooctanol, the yield of the target product was 56%.

[0126] Example 32 Preparation of benzaldehyde

[0127] In a transparent quartz bottle equipped with a rubber stopper and a magnetic stir bar, toluene (10 mmol) and 0.25 mol% hydrobromic acid were added to 12 mL of reaction solvent. The reaction mixture was stirred under light irradiation in an oxygen atmosphere at ambient temperature. The reaction progress was monitored by GC or TLC during the reaction. The reaction was completed in 1 hour at ambient temperature. The amount of the target product was calculated by GC analysis. The amount of benzaldehyde was 349,800 μmol·g. HBr -1 The selectivity rate is 95%.

[0128] Example 33 Preparation of p-Toluene

[0129] Same as Example 32, except that the reaction substrate toluene was replaced with p-xylene, and the amount of p-methylbenzaldehyde was 327,600 μmol·g. HBr -1 The selectivity rate was 92%.

[0130] Example 34 Preparation of p-fluorobenzaldehyde

[0131] Same as Example 32, except that the reaction substrate toluene was replaced with p-fluorotoluene, and the amount of p-fluorobenzaldehyde was 318200 μmol·g. HBr -1 The selectivity rate was 94%.

[0132] Example 35 Preparation of p-chlorobenzaldehyde

[0133] Same as Example 32, except that the reaction substrate toluene was replaced with p-chlorotoluene, and the amount of p-chlorobenzaldehyde was 341300 μmol·g. HBr -1 The selectivity rate was 94%.

[0134] Example 36 Preparation of p-bromobenzaldehyde

[0135] Same as Example 32, except that the reaction substrate toluene was replaced with p-bromotoluene, and the amount of p-bromobenzaldehyde was 320800 μmol·g. HBr -1 The selectivity rate was 93%.

[0136] Example 37 Preparation of n-hexanal

[0137] Same as Example 32, except that the reaction substrate toluene was replaced with n-hexane, and the amount of n-hexanal was 112400 μmol·g. HBr -1 The selectivity rate was 81%.

[0138] When alcohols are used as reactants, the reaction equation is as follows:

[0139]

[0140] The extended structural formulas of the substrates for the photoinduced selective oxidation of alcohols to aldehydes / ketones are as follows:

[0141]

[0142]

[0143] When hydrocarbons are used as reactants, the reaction equation is as follows:

[0144]

[0145] The extended structural formulas of reaction substrates for the photoinduced selective oxidation of hydrocarbons to aldehydes are as follows:

[0146]

[0147] The substrates for the photoinduced selective oxidation of hydrocarbons to aldehydes are expanded as shown in Table 1 below:

[0148] Table 1

[0149]

[0150]

[0151] Experiments were conducted on the Tyndall effect in the light-driven selective preparation of carbonyl compounds:

[0152] like Figure 3As shown in Figure a, no Tyndall effect was observed when BA was dissolved in EA solution. However, when HBr was added to the BA EA solution, a Tyndall effect was observed, but it was not significant, possibly due to the small size of BA molecules. Therefore, 1-pyrene methanol (PM), with a larger molecular size, was used in the Tyndall effect experiment. Similarly, no Tyndall effect was observed in the PM EA solution. Surprisingly, a significant Tyndall effect appeared when HBr was added to the PM EA solution. Figure 3 a) Furthermore, the Tyndall phenomenon was not observed in a CH2Cl2 solution containing both PM and HBr, but it appeared upon the addition of EA to the CH2Cl2 solution. This confirms the unique role of solvent EA in the self-assembly of molecules to form microemulsion complexes. The results of the Tyndall experiment indicate that microemulsions are formed by the spontaneous aggregation of molecules within the reaction system.

[0153] Figure 3 As shown in Figure b, it is speculated that the microemulsions formed in the reaction system may be formed by the self-assembly and aggregation of complexes through non-covalent interactions between reionic molecules. Species [EA…(BAH)] + Br - The BA is formed through the protonation of HBr, and the hydrogen bonding interactions lead to the pre-organization of BA, HBr, and EA molecules. Therefore, this complex system is considered a potential source of high selectivity and activity in photoinduced aerobic oxidation of alcohols.

[0154] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a carbonyl compound, characterized in that, The preparation method includes: In an oxygen-containing atmosphere, a mixture containing alcohols or hydrocarbons, acidic compounds, and solvents is reacted by light irradiation to obtain the carbonyl compounds. The alcohols or hydrocarbons, acidic compounds, solvents, and oxygen-containing atmosphere spontaneously form a reaction catalyst. The alcohol or hydrocarbon is selected from one of Formula I-1, Formula I-2, and Formula I-3; Equation I-1; Equation I-2; Formula I-3; The carbonyl compound is selected from one of formula II-1, formula II-2, and formula II-3; Formula II-1; Formula II-2; Formula II-3; In Equations I-1 and II-1, R 1 R 2 Independently selected from hydrogen, halogen, nitro, cyano, trifluoromethyl, C1~C 10 Alkyl, C1~C 10 Substituted alkyl groups, C6~C 10 aryl, C4~C 10 One of the heteroaryl groups; In Equations I-2 and II-2, R 3 R 4 Independently selected from hydrogen, C1~C 10 Alkyl, C1~C 10 One of the substituted alkyl groups; The substituents of the substituted alkyl group are selected from C6~C6. 10 One of the aryl groups; In Equations I-3 and II-3, R 5 Independently selected from C1~C 10 Alkyl groups, C6~C 10 aryl, C6~C 10 One of the substituted aryl groups; Wherein, the substituent in the substituted aryl group is selected from one of halogen, nitro, and cyano; The solvent is selected from at least one of ethyl acetate, methyl propionate, and ethyl propionate; The acidic compound is hydrobromic acid; The molar ratio of the acidic compound, alcohol or hydrocarbon, and solvent is 1:5:(1000~10000) or 1:400:(1000~10000).

2. The preparation method according to claim 1, characterized in that, The carbonyl compounds are selected from benzaldehyde, 4-fluorobenzaldehyde, 2-bromobenzaldehyde, 4-iodobenzaldehyde, 4-nitrobenzaldehyde, 4-trifluoromethylbenzaldehyde, 3-cyanobenzaldehyde, 4-cyanobenzaldehyde, 4-carboxybenzaldehyde, 4-carboxylic acid methyl ester benzaldehyde, 4-tert-butylbenzaldehyde, 4-phenylbenzaldehyde, 3,5-dinitrobenzaldehyde, 3,4,5-trimethoxybenzaldehyde, pentafluorobenzaldehyde, naphthaldehyde, pyrene formaldehyde, furanaldehyde, benzofuran-2-carboxaldehyde, benzothiazole-2-carboxaldehyde, p-dibenzoaldehyde, benzophenone, 4-chlorobenzophenone, and 4,4-dicyanobenzophenone. 2,2-Diphenyldione, acetophenone, cyclohexanone, cyclooctanone, p-methylbenzaldehyde, p-fluorobenzaldehyde, p-chlorobenzaldehyde, p-bromobenzaldehyde, n-hexanol, or one of the structures shown in 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, 2l, 2m, 2n, 2o, 2p, 2q, 2r, 2s, 2t, 2u, 2v, 2w, 2x, 2y, 2z, 2aa, 2ab, 2ac, 2ad, 2ae, 2af, 2ag, 2ah, 2ai, 2aj, 2ak, 2al, 2am, 2an, 2ao, 2ap, 2aq, 2ar, 2as; 。 3. The preparation method according to claim 1, characterized in that, The oxygen volume fraction in the oxygen-containing atmosphere is 20-100%.

4. The preparation method according to claim 1, characterized in that, The reaction temperature is 20~50℃.

5. The preparation method according to claim 1, characterized in that, The reaction time is 0.15 to 8 hours.

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