CN102731234A - CO (carbon monoxide)-promoted method for directly oxygenizing hydroxylated aromatic compound by molecular oxygen - Google Patents

Abstract

The invention belongs to the technical field of catalytic synthesis, and specifically relates to a method for directly oxidizing hydroxylated aromatic compounds with molecular oxygen promoted by CO. The method of the present invention uses an aromatic hydrocarbon compound as a substrate, uses a combined catalyst composed of a supported noble metal catalyst and a heteroatom molecular sieve or heteropolyacid salt containing Ti, V, Cu or Fe, and uses a mixed solution of water and an organic solvent as a solvent; Through CO and O ₂ , under the promotion of CO, the hydroxylated aromatic compound is directly oxidized by molecular oxygen to prepare the corresponding phenolic compound. The equipment and process used in the method of the invention are simple, the separation of the target product is relatively easy, the reaction conditions are mild, the system environment is friendly, and it is a green process route.

Description

A CO-promoted method for the direct oxidation of hydroxylated aromatic compounds by molecular oxygen

technical field

The invention belongs to the technical field of catalytic synthesis, and in particular relates to a method for direct hydroxylation of aromatic compounds.

Background technique

Hydroxylation products of aromatic compounds are important compounds in the chemical and pharmaceutical fields. For example: Methyl p-hydroxybenzoate is a preservative additive in medicine, food, spices, and film, and it is also a strong bactericide. However, at present, most of the hydroxylation products of aromatic compounds are prepared through multi-step reaction methods, the process is complicated, the equipment requirements are high, and it is not good for production. Phenol, one of the hydroxylation products of aromatic hydrocarbons, is a very important bulk organic chemical raw material, and has broad applications in the fields of pharmaceutical intermediates, pesticides, spices, dyes, auxiliaries, and resins. At present, the main production method of phenol is the cumene oxidation method. This method undergoes a three-step reaction. The main disadvantages are complicated processes, high energy consumption, and serious corrosion of equipment. In particular, the demand for its by-product acetone is much lower than that of phenol. Therefore, the study of new processes for the direct hydroxylation of aromatic compounds to phenolic compounds has received widespread attention.

The existing new process of one-step hydroxylation of benzene to phenol, if divided according to the oxidant used, hydrogen peroxide is the most relevant research. Literature (KM Parida, D. Rath, Appl. Catal. A: Gen., 321 (2007): 101-108) used Cu/MCM-41 as catalyst to synthesize phenol in acetic acid in liquid phase, the conversion rate of benzene and phenol The selectivities were 21% and 94%, respectively. In addition, Chinese patent CN129961C discloses that acid-treated activated carbon is used as a catalyst, and under liquid phase reaction conditions, the conversion rate of benzene is 11-13%. In addition, there are some reports using N ₂ O as the oxidizing agent. Literature (D. Meloni, R. Monaci, V. Solinas, et al, J. Catal., 314 (2003): 169-178) used Fe-MFI molecular sieve as a catalyst to synthesize phenol by gas phase reaction at a reaction temperature of 400 ^o C The conversion of benzene and the selectivity of phenol were 20% and 90%, respectively. Compared with the traditional method, the above method simplifies the process and improves the utilization rate of atoms, but the main disadvantages are that N ₂ O and hydrogen peroxide are expensive, and the selectivity of phenol based on the oxidizing agent is not high.

The direct hydroxylation of benzene rings using molecular oxygen as an oxidant has long been a goal in both industrial and academic research, and is considered one of the top ten most challenging topics in the field of catalysis. As early as 1888, Friedel and Crafts had tried to study the direct hydroxylation of benzene under gas phase reaction conditions with oxygen as oxidant and aluminum trichloride as catalyst. Since then, research on molybdenum, tungsten, copper or vanadium-based materials as catalysts has emerged in an endless stream, literature (H. Yamanaka, R. Hamada, H. Nibuta, et al, J. Mol. Catal. A: Chemical, 178 (2002) : 89-95) The yield of phenol obtained by using Cu/ZSM-5 as a catalyst was 1.5%; literature (Y. Liu, K. Murata, M. Inaba, Catal. Commun., 6 (2005): 679-683) Using [(C ₄ H ₉ ) ₄ N] ₅ [PW ₁₁ CuO ₃₉ (H ₂ O)] as catalyst, benzene was oxidized to phenol in liquid phase. The conversion of benzene and the selectivity of phenol were 9.2% and 91.8%, respectively. When molecular oxygen is used as an oxidant, although its price is low, the conversion rate of benzene is low, usually not more than 20%. Aiming at the problem of low benzene oxidation ability when molecular oxygen is used as oxidant, the literature (S. Niwa, M. Eswaramoorthy, J. Nair, et al, Science, 295 (2002): 105-107) uses palladium membrane as catalyst, oxygen As an oxygen source, hydrogen as an auxiliary agent, the raw material benzene can be converted into phenol in a fixed bed reactor, but the conversion rate of benzene is not high, and the selectivity of hydrogen to phenol is low. In addition, the literature (SL Shu, Y. Huang, XJ Hu, J. Phys. Chem. C, 113 (2009): 19618-19622) concluded through repeated experiments that the above-mentioned palladium membrane catalyst did not directly catalyze benzene under the reaction conditions. The performance of hydroxylation, and the combustion reaction of hydrogen and oxygen on the surface of the catalyst can easily cause damage to the structure of the membrane catalyst, which is very detrimental to the stability of the catalyst. Therefore, the application prospect of the direct hydroxylation process of molecular oxygen oxidation of benzene with hydrogen as auxiliary agent remains to be discussed.

Contents of the invention

The purpose of the present invention is to provide a new method for the direct hydroxylation of aromatic hydrocarbons to produce phenolic compounds, so as to overcome the existing problems in the existing aromatic hydrocarbon hydroxylation process.

The solution provided by the present invention is: use aromatic compounds as substrates, use a combined catalyst composed of supported noble metal catalysts and heteroatom molecular sieves or heteropolyacids containing Ti, V, Cu or Fe, and use water and organic solvents The mixed solution is a solvent; CO and O ₂ are fed in, the pressure ratio of CO and O ₂ is 0.1:1 to 9:1, and the total pressure is 0.5 to 3 MPa; under the promotion of CO, the hydroxylated aromatic compound is directly oxidized by molecular oxygen , the reaction temperature is 20-150 ^oC , and the corresponding phenolic compound is prepared; wherein, the mass ratio of the substrate and the solvent is 0.01:1-0.2:1.

In the present invention, the metal in the supported noble metal catalyst is selected from one or more of Pt, Pd, Rh, Ru, Ir, Au or Ag, and the carrier is selected from TiO ₂ , CeO ₂ , Fe ₂ O ₃ , One or more of Al ₂ O ₃ and ZrO ₂ . The supported noble metal catalyst can be prepared by the following methods: coprecipitation method, deposition precipitation method, colloid method or impregnation method.

In the present invention, the heteroatom molecular sieve or heteropolyacid salt containing Ti, V, Cu or Fe is selected from silica molecular sieves of MFI, MWW, MCM, HMS, Beta or SBA configuration containing Ti, V, Cu or Fe, One or more of Cu-containing aluminum phosphate molecular sieve and V-containing tungstate or molybdate.

The molar ratio of the substrate to the noble metal catalyst in the combined catalyst is 50:1 to 1000:1; in the combined catalyst, the mass ratio of the supported noble metal catalyst to the heteroatom molecular sieve or heteropolyacid salt is 0.5:1 ~2:1.

In the present invention, the reaction solvent is a mixed solvent of an organic solvent and water, and the organic solvent is selected from methanol, acetone, acetonitrile or acetic acid; the volume ratio of the organic solvent to water in the mixed solvent is 1:9 to 9:1 .

In the present invention, the aromatic hydrocarbon compound is substituted/unsubstituted benzene and substituted/unsubstituted condensed ring aromatic hydrocarbon. The substituents are one or more of alkyl, alkoxy, hydroxyl, fluorine, chlorine, bromine, iodine, cyano, acyl, trifluoromethyl, nitro or carboxyl.

Compared with the existing method, the present invention has the following advantages: environmental friendliness, less reaction corrosion, light waste treatment burden, can meet the requirements of clean production, and is conducive to large-scale production; mild reaction conditions, is a green process route. The catalyst used is a heterogeneous catalyst, the operation is simple, and the separation of the product and the catalyst is easy.

Detailed ways

The present invention is described in further detail below through examples, but the content of the present invention is not limited thereto.

Example 1: Weigh 0.664 g H ₂ PtCl ₆ ·9H ₂ O, 0.420 g PdCl ₂ , 0.508 g RhCl ₃ , 0.646 g RuCl ₃ ·3H ₂ O, 0.670 g H ₂ IrCl ₆ ·6H ₂ O or 0.390 g AgNO ₃ Put them into six 100 mL beakers respectively, then add 5 g ZrO ₂ and 20 mL water respectively, carefully evaporate the water in an 80 ^o C water bath under stirring, and dry the obtained samples in an oven at 100 ^o C for 12 hours, transfer the solid to Put it into a crucible and bake in a muffle furnace at 350 ^o C for 2 hours, and then bake it in a 5% H ₂ /Ar flow at 300 ^o C for 2 hours. After cooling a catalyst is obtained, denoted as Pt/ZrO ₂ -Im, Pd/ZrO ₂ -Im, Rh/ZrO ₂ -Im, Ru/ZrO ₂ -Im, Ir/ZrO ₂ -Im or Ag/ZrO ₂ -Im.

Example 2: Weigh 0.664 g H ₂ PtCl ₆ 9H ₂ O or 0.420 g PdCl ₂ into two 100 mL beakers respectively, then add 5 g TiO ₂ and 40 mL 0.25M NaOH in ethylene glycol solution, After stirring at room temperature for 1 hour, raise the temperature to 140 ^o C and continue stirring for 3 hours, filter the precipitate, wash with distilled water three times, dry at 100 ^o C for 12 hours, and obtain the catalyst after cooling, expressed as Pt/TiO ₂ -CD or Pd/TiO ₂ -CD.

Example 3: Put 0.104 g HAuCl ₄ 4H ₂ O, 0.5 L of water into a 1 L beaker, drop in a 0.2 M sodium hydroxide solution with stirring at 80 ^o C until the pH is about 7, and then add 5 g CeO ₂ , continued stirring at 80 ^o C for 2 hours, filtered the precipitate, washed it with distilled water until it was free of Cl ^- , dried it at 100 ^o C for 12 hours, and finally roasted it in a muffle furnace at 300 ^o C for 4 hours. After cooling a catalyst was obtained, denoted as Au/CeO ₂ -DP.

Example 4: Put 0.468 g HAuCl ₄ 4H ₂ O, 12.65 g Fe(NO ₃ ) ₃ 9H ₂ O, and 0.5 L water into a 1 L beaker, and drop in 0.2 M hydrogen with stirring at 80 ^o C Sodium oxide solution until the pH is about 8, continue to stir for 30 minutes, filter the precipitate, wash with distilled water until there is no Cl ^- , dry at 100 ^o C for 12 hours, and finally bake in a muffle furnace at 300 ^o C for 4 hours. After cooling a catalyst was obtained, denoted as Au/Fe ₂ O ₃ -CP.

Embodiment 5: Weigh 0.1 g of the catalyst prepared in Examples 1 to 4, 0.1 g of Ti-MWW molecular sieve and 2 mmol of benzene and put it into a 100 mL stainless steel autoclave filled with 5 mL of water and 5 mL of acetone, and then After replacing the air in the autoclave with carbon monoxide, the internal temperature of the autoclave was raised to 80 ^o C, 0.5 MPa of carbon monoxide was introduced, and then oxygen was introduced until the total pressure was 1 MPa, stirred for 4 hours, and the product was determined by gas chromatography. Benzene conversion rate, phenol selectivity and hydroquinone selectivity are shown in Table 1.

the

Table 1 Example 5 results

Supported noble metal catalyst Benzene conversion % Phenol selectivity % Hydroquinone selectivity % Pt/ZrO ₂ -Im 58 92 8 Pd/ZrO ₂ -Im 56 93 7 Rh/ZrO ₂ -Im 32 96 4 Ru/ZrO ₂ -Im 31 95 5 Ir/ZrO ₂ -Im 47 95 4 Ag/ZrO ₂ -Im 13 97 3 Pt/TiO ₂ -CD 42 94 6 Pd/TiO ₂ -CD 47 94 6 Au/CeO ₂ -DP 45 94 6 Au/Fe ₂ O ₃ -CP 36 95 5

Example 6: Weigh 0.1 g Pt/ZrO ₂ -Im, 0.1 g Ti-MWW molecular sieve and 2 mmol benzene into a 100 mL stainless steel autoclave filled with 5 mL water and 5 mL acetone, and then replace the autoclave with carbon monoxide After the air, the internal temperature of the autoclave was raised to 40 ^o C, 50 ^o C, 60 ^o C, 70 ^{o C} or 80 ^o C, and 0.5 MPa of carbon monoxide was introduced, and then oxygen was introduced to a total pressure of 1 MPa, and stirred for 4 hours. The product was determined by gas chromatography. Benzene conversion rate, phenol selectivity and hydroquinone selectivity are shown in Table 2.

Table 2 embodiment 6 result

Reaction temperature ^o C Benzene conversion % Phenol selectivity % Hydroquinone selectivity % 40 31 97 3 50 37 97 3 60 42 95 5 70 49 94 6 80 58 92 8

Example 7: Weigh 0.1 g Pt/ZrO ₂ -Im, 0.1 g Ti-MWW molecular sieve and 2 mmol benzene into a 100 mL stainless steel autoclave filled with 10 mL of organic solvent (methanol, acetone or acetonitrile) and water, The volume ratio of organic solvent to water is 1:2, 1:1 or 2:1 respectively. After replacing the air in the autoclave with carbon monoxide, the internal temperature of the autoclave is raised to 80 ^o C, and 0.5 MPa of carbon monoxide is introduced, and then Oxygen to a total pressure of 1 MPa, stirred for 4 hours, and the product was determined by gas chromatography. Benzene conversion rate, phenol selectivity and hydroquinone selectivity are shown in Table 3.

Table 3 embodiment 8 result

water mL Organic solvent/volume mL Benzene conversion % Phenol selectivity % Hydroquinone selectivity % 3.3 Methanol/6.7 39 97 3 5 Methanol/5 53 93 7 6.7 Methanol/3.3 45 96 4 3.3 Acetone/6.7 55 94 6 5 Acetone/5 58 92 8 6.7 Acetone/3.3 45 96 4 3.3 Acetonitrile/6.7 32 95 5 5 Acetonitrile/5 44 95 5 6.7 Acetonitrile 3.3 48 94 6

Example 9: Weigh 0.1 g of Pt/ZrO ₂ -Im, 0.1 g of Ti-MWW molecular sieve and 2 mmol of benzene into 5 mL, 8 mL, 10 mL, 15 mL or 20 mL of benzene with a volume ratio of 1:1. In a 100 mL stainless steel autoclave with a mixed solvent of water and acetone, after replacing the air in the autoclave with carbon monoxide, the internal temperature of the autoclave was raised to 80 ^o C, 0.5 MPa of carbon monoxide was introduced, and then oxygen was introduced until the total pressure was 1 MPa. After stirring for 4 hours, the product was determined by gas chromatography. Benzene conversion rate, phenol selectivity and hydroquinone selectivity are shown in Table 4.

Table 4 Example 9 Results

Solvent volume mL Benzene conversion % Phenol selectivity % Hydroquinone selectivity % 5 56 91 9 8 57 92 8 10 58 92 8 15 51 94 6 20 46 94 6

Example 10: Weigh 0.1 g of Pt/ZrO ₂ -Im and 2 mmol of benzene into a 100 mL stainless steel autoclave filled with 5 mL of water and 5 mL of acetone, and then add 0.1 g of TS-1, Ti-MWW, and Ti -Beta, Ti-MCM-41, Ti-SBA-15, Ti-HMS, Fe-ZSM-5, Cu-AlPO ₄ -5, Cu-SBA-15, V-SBA-15 molecular sieve or H ₄ PMo ₁₁ VO ₄₀ , then replace the air in the autoclave with carbon monoxide, increase the internal temperature of the autoclave to 80 ^o C, feed 0.5 MPa carbon monoxide, and then feed oxygen until the total pressure is 1 MPa, stir for 4 hours, and measure the product by gas chromatography. Benzene conversion rate, phenol selectivity and hydroquinone selectivity are shown in Table 5.

Table 5 embodiment 10 result

catalyst Benzene conversion % Phenol selectivity % Hydroquinone selectivity % TS-1 41 96 4 Ti-MWW 58 92 8 Ti-MCM-41 38 94 6 Ti-SBA-15 39 95 5 Ti-HMS 14 97 3 Fe-ZSM-5 15 93 7 Cu-AlPO ₄ -5 26 82 18 Cu-SBA-15 twenty one 89 11 V-SBA-15 39 88 12 H ₄ PMo ₁₁ VO ₄₀ 53 97 3

Example 11: Weigh 0.1 g Pt/ZrO ₂ -Im, 0.1 g Ti-MWW molecular sieve and 2 mmol benzene into a 100 mL stainless steel autoclave filled with 5 mL water and 5 mL acetone, and then replace the autoclave with carbon monoxide After adding air, raise the internal temperature of the autoclave to 80 ^o C. According to the pressure ratio of carbon monoxide and oxygen at 1:9, 3:7, 1:1, 7:3 or 9:1, carbon monoxide and oxygen are successively introduced to control the total pressure. It was 1 MPa, stirred for 4 hours, and the product was determined by gas chromatography. Benzene conversion rate, phenol selectivity and hydroquinone selectivity are shown in Table 6.

Table 6 Example 11 results

carbon monoxide MPa Oxygen MPa Benzene conversion % Phenol selectivity % Hydroquinone selectivity % 0.1 0.9 11 99 1 0.3 0.7 39 94 6 0.5 0.5 58 92 8 0.7 0.3 50 95 5 0.9 0.1 32 96 4

Example 12: Weigh 0.1 g Pt/ZrO ₂ -Im, 0.1 g Ti-MWW molecular sieve and 2 mmol benzene into a 100 mL stainless steel autoclave filled with 5 mL water and 5 mL acetone, and then replace the air in the autoclave with carbon monoxide Finally, the internal temperature of the autoclave was increased to 80 ^o C, and carbon monoxide and oxygen were introduced successively according to the pressure ratio of carbon monoxide and oxygen at 1:1, and the total pressure was controlled to be 0.5, 1, 2 or 3 MPa respectively, and stirred for 4 hours. Chromatographic determination. Benzene conversion rate, phenol selectivity and hydroquinone selectivity are shown in Table 7.

Table 7 Example 12 results

total pressure MPa Benzene conversion % Phenol selectivity % Hydroquinone selectivity % 0.5 40 93 7 1 58 92 8 2 64 91 9 3 71 90 10

Example 13: Weigh 0.1 g Pt/ZrO ₂ -Im, 0.1 g Ti-MWW molecular sieve and 2 mmol toluene into a 100 mL stainless steel autoclave filled with 5 mL water and 5 mL acetone, and then replace the autoclave with carbon monoxide After the air is removed, the internal temperature of the autoclave is raised to 80 ^o C, 0.5 MPa carbon monoxide is introduced, and then oxygen is introduced until the total pressure is 1 MPa, stirred for 4 hours, and the product is determined by gas chromatography. Toluene conversion rate is 53%, p-cresol selectivity is 98%.

Example 14: Weigh 0.1 g Pt/ZrO ₂ -Im, 0.1 g Ti-MWW molecular sieve and 2 mmol anisole into a 100 mL stainless steel autoclave filled with 5 mL water and 5 mL acetone, and then replace the high pressure with carbon monoxide After the air in the autoclave, the internal temperature of the autoclave was raised to 80 ^o C, 0.5 MPa carbon monoxide was introduced, and then oxygen was introduced until the total pressure was 1 MPa, stirred for 4 hours, and the product was determined by gas chromatography. Anisole conversion rate is 46%, p-methoxyphenol selectivity is 98%.

Example 15: Weigh 0.1 g Pt/ZrO ₂ -Im, 0.1 g Ti-MWW molecular sieve and 2 mmol chlorobenzene into a 100 mL stainless steel autoclave filled with 5 mL water and 5 mL acetone, and then replace the autoclave with carbon monoxide After neutralizing the air, raise the internal temperature of the autoclave to 80 ^o C, feed 0.5 MPa carbon monoxide, and then feed oxygen until the total pressure is 1 MPa, stir for 4 hours, and measure the product by gas chromatography. The conversion rate of chlorobenzene is 32%, and the selectivity to p-chlorophenol is 99%.

Example 16: Weigh 0.1 g Pt/ZrO ₂ -Im, 0.1 g Ti-MWW molecular sieve and 2 mmol benzoic acid into a 100 mL stainless steel autoclave filled with 5 mL water and 5 mL acetone, and then replace the autoclave with carbon monoxide After the air is removed, the internal temperature of the autoclave is raised to 80 ^o C, 0.5 MPa carbon monoxide is introduced, and then oxygen is introduced until the total pressure is 1 MPa, stirred for 4 hours, and the product is determined by gas chromatography. The conversion rate of benzoic acid is 29%, and the selectivity of p-hydroxybenzoic acid is 98%.

Example 17: Weigh 0.1 g Pt/ZrO ₂ -Im, 0.1 g Ti-MWW molecular sieve and 2 mmol phenol into a 100 mL stainless steel autoclave filled with 5 mL water and 5 mL acetone, and then replace the autoclave with carbon monoxide After the air is removed, the internal temperature of the autoclave is raised to 80 ^o C, 0.5 MPa carbon monoxide is introduced, and then oxygen is introduced until the total pressure is 1 MPa, stirred for 4 hours, and the product is determined by gas chromatography. The conversion rate of phenol was 68%, the selectivity of hydroquinone was 70%, and the selectivity of catechol was 30%.

Example 18: Weigh 0.1 g Pt/ZrO ₂ -Im, 0.1 g Ti-MWW molecular sieve and 2 mmol naphthalene into a 100 mL stainless steel autoclave filled with 5 mL water and 5 mL acetone, and then replace the autoclave with carbon monoxide After the air is removed, the internal temperature of the autoclave is raised to 80 ^o C, 0.5 MPa carbon monoxide is introduced, and then oxygen is introduced until the total pressure is 1 MPa, stirred for 4 hours, and the product is determined by gas chromatography. The conversion of naphthalene was 47%, the selectivity of β-naphthol was 64%, and the selectivity of α-naphthol was 36%.

Example 19: Weigh 0.1 g of the catalyst prepared in Examples 1 to 4, 0.1 mmol H ₅ SW ₁₁ VO ₄₀ heteropolyacid and 2 mmol benzene and put it into 100 mL stainless steel containing 5 mL water and 5 mL acetic acid In the autoclave, after replacing the air in the autoclave with carbon monoxide, the internal temperature of the autoclave was raised to 80 ^o C, and 0.5 MPa carbon monoxide was introduced, and then oxygen was fed to a total pressure of 1 MPa, stirred for 4 hours, and the product was analyzed by gas chromatography. Determination. Benzene conversion rate, phenol selectivity and hydroquinone selectivity are shown in Table 8.

Table 8 embodiment 19 results:

Supported noble metal catalyst Benzene conversion % Phenol selectivity % Hydroquinone selectivity % Pt/ZrO ₂ -Im 36 87 13 Pd/ZrO ₂ -Im 42 83 17 Rh/ZrO ₂ -Im 27 89 11 Ru/ZrO ₂ -Im 30 89 11 Ir/ZrO ₂ -Im 31 90 10 Ag/ZrO ₂ -Im 11 93 7 Au/CeO ₂ -DP 18 94 6

Example 20: Weigh 0.1 g Pd/ZrO ₂ -Im, 0.1 mmol H ₅ SMo ₁₁ VO ₄₀ heteropolyacid and 2 mmol benzene into a 100 mL stainless steel autoclave filled with 5 mL water and 5 mL acetic acid, and then use After replacing the air in the autoclave with carbon monoxide, the internal temperature of the autoclave was raised to 80 ^o C, 0.5 MPa of carbon monoxide was introduced, and then oxygen was introduced until the total pressure was 1 MPa, stirred for 4 hours, and the product was determined by gas chromatography. The conversion rate of benzene was 38%, the selectivity of phenol was 85%, and the selectivity of hydroquinone was 15%.

Example 21: Weigh 0.1 g Pd/ZrO ₂ -Im, 0.1 mmol H ₅ SW ₁₁ VO ₄₀ heteropoly acid and 2 mmol naphthalene into a 100 mL stainless steel autoclave filled with 5 mL water and 5 mL acetic acid, and then use After replacing the air in the autoclave with carbon monoxide, the internal temperature of the autoclave was raised to 80 ^o C, 0.5 MPa of carbon monoxide was introduced, and then oxygen was introduced until the total pressure was 1 MPa, stirred for 4 hours, and the product was determined by gas chromatography. The conversion of naphthalene was 39%, the selectivity of β-naphthol was 69%, and the selectivity of α-naphthol was 31%.

Example 22: Weigh 0.1 g Pd/ZrO ₂ -Im, 0.1 mmol H ₅ SW ₁₁ VO ₄₀ heteropoly acid and 2 mmol toluene into a 100 mL stainless steel autoclave filled with 5 mL water and 5 mL acetic acid, and then use After replacing the air in the autoclave with carbon monoxide, the internal temperature of the autoclave was raised to 80 ^o C, 0.5 MPa of carbon monoxide was introduced, and then oxygen was introduced until the total pressure was 1 MPa, stirred for 4 hours, and the product was determined by gas chromatography. Toluene conversion rate is 42%, p-cresol selectivity is 88%.

Claims (10)

1. A method for hydroxylating aromatic hydrocarbon compounds by molecular oxygen direct oxidation promoted by CO is characterized in that aromatic hydrocarbon compounds are used as substrates, a combined catalyst consisting of a supported noble metal catalyst and a heteroatom molecular sieve or heteropoly acid salt containing Ti, V, Cu or Fe is used, and a mixed solution of water and an organic solvent is used as a solvent; introducing CO and O₂CO and O₂The pressure ratio is 0.1: 1-9: 1, the total pressure is 0.5-3 MPa; under the promotion of CO, the aromatic hydrocarbon compound is directly oxidized and hydroxylated by molecular oxygen, and the reaction temperature is 20-150 DEG ^oCTo prepare corresponding phenolic compounds; wherein,the mass ratio of the substrate to the solvent is 0.01: 1-0.2: 1.

2. the method of claim 1, wherein the supported noble metal catalyst comprises one or more metals selected from the group consisting of Pt, Pd, Rh, Ru, Ir, Au, and Ag.

3. The method of claim 1 wherein the supported noble metal catalyst support is selected from the group consisting of TiO₂、CeO₂、Fe₂O₃、Al₂O₃And ZrO₂One or more of them.

4. The method according to claim 2 or 3, wherein the supported noble metal catalyst is prepared by the following method: coprecipitation, precipitation, colloid or impregnation.

5. The method of claim 1, wherein the heteroatom molecular sieve or heteropolyacid salt containing Ti, V, Cu or Fe is selected from one or more of a silica molecular sieve containing Ti, V, Cu or Fe in MFI, MWW, MCM, HMS, Beta or SBA configuration, an aluminum phosphate molecular sieve containing Cu and tungstate or molybdate containing V.

6. The method of claim 1, wherein the molar ratio of the substrate to the noble metal catalyst in the combined catalyst is from 50: 1-1000: 1; in the combined catalyst, the mass ratio of the supported noble metal catalyst to the heteroatom molecular sieve or heteropolyacid salt is 0.5: 1-2: 1.

7. the method according to claim 1, wherein the volume ratio of the organic solvent to the water in the mixed solvent is 1: 9-9: 1.

8. the method of claim 7, wherein the organic solvent is selected from methanol, acetone, acetonitrile, or acetic acid.

9. The method of claim 1, wherein the aromatic hydrocarbon compounds are substituted/unsubstituted benzene and substituted/unsubstituted polycyclic aromatic hydrocarbons.

10. The method according to claim 9, wherein the substituent of the substituted benzene and the substituted polycyclic aromatic hydrocarbon is one or more of alkyl, alkoxy, hydroxyl, fluorine, chlorine, bromine, iodine, cyano, acyl, trifluoromethyl, nitro or carboxyl.