阅读说明：本技术 一种金属卟啉催化氧化芳烃苄位仲c-h键合成芳香酮的方法 (Method for preparing aromatic ketone by virtue of catalytic oxidation of aromatic hydrocarbon benzyl secondary C-H bond by virtue of metalloporphyrin ) 是由 佘远斌 刘磊 沈海民 于 2020-04-27 设计创作，主要内容包括：一种金属卟啉催化氧化芳烃苄位仲C-H键合成芳香酮的方法,所述方法包括：将金属卟啉(1×10<Sup>-4</Sup>％～1％,mol/mol)分散于芳烃中,密封反应体系,搅拌下升温至80～150℃,通入氧化剂至0.20～2.0MPa,保持设定的温度和压力,搅拌反应3.0～24.0h,之后反应液经后处理,得到产物芳香酮类化合物。本发明所述方法,不含任何溶剂和助剂,反应温度低,催化剂用量少,芳香酮类化合物选择性高,过氧化物含量低,生产安全系数高,具有解决目前工业上芳烃苄位仲C-H键催化氧化过程中,反应温度高,腐蚀性溶剂和助剂的使用,芳香酮选择性低,芳香酮易深度氧化等不足的潜力。本发明高效、可行、安全。(A method for preparing aromatic ketone by catalytic oxidation of aromatic hydrocarbon benzyl secondary C-H bond with metalloporphyrin comprises the step of carrying out catalytic oxidation on metalloporphyrin (1 × 10) ‑4 Percent to 1 percent, mol/mol) are dispersed in aromatic hydrocarbon, the reaction system is sealed, and the mixture is stirred and heated upAnd (3) heating to 80-150 ℃, introducing an oxidant to 0.20-2.0 MPa, keeping the set temperature and pressure, stirring for reaction for 3.0-24.0 h, and performing post-treatment on the reaction liquid to obtain the aromatic ketone compound. The method disclosed by the invention does not contain any solvent or auxiliary agent, is low in reaction temperature, small in catalyst dosage, high in selectivity of aromatic ketone compounds, low in peroxide content and high in production safety coefficient, and has the potential of overcoming the defects of high reaction temperature, use of corrosive solvents and auxiliary agents, low selectivity of aromatic ketone, easiness in deep oxidation of aromatic ketone and the like in the existing industrial aromatic benzyl secondary C-H bond catalytic oxidation process. The invention is efficient, feasible and safe.)

1. A method for catalytic oxidation of aromatic hydrocarbon benzyl secondary C-H bonding into aromatic ketone by metalloporphyrin, which is characterized by comprising the following steps:

dispersing metalloporphyrin in aromatic hydrocarbon containing benzyl secondary C-H bonds, sealing a reaction system, heating to 80-150 ℃ under stirring, introducing an oxidant to 0.20-2.0 MPa, keeping the set temperature and pressure, stirring for reaction for 3.0-24.0H, and treating the reaction solution after the reaction is finished to obtain a product aromatic ketone;

the metalloporphyrin is at least one of compounds shown in a formula (I):

in the formula (I), R₁、R₂、R₃、R₄、R₅Each independently is: hydrogen, methyl, ethyl, propyl, butyl, isopropyl, tert-butyl, phenyl, 1-naphthyl, 2-naphthyl, methoxy, ethoxy, hydroxy, mercapto, amino, methylamino, ethylamino, dimethylamino, 1-hydroxyethyl, nitro, cyanoCarboxy, benzyl, methoxycarbonyl, fluoro, chloro, bromo or iodo; m is Co²⁺、Mn²⁺、Ni²⁺、Fe²⁺、Cu²⁺Or Zn²⁺；

The ratio of the quantity of the metalloporphyrin to the quantity of the aromatic hydrocarbon containing benzyl secondary C-H bond is 1: 1000000-1: 100, respectively;

the metalloporphyrin is 5,10,15, 20-tetra (2,3, 6-trichlorophenyl) cobalt porphyrin (II), 5,10,15, 20-tetra (2, 6-dichlorophenyl) cobalt porphyrin (II), 5,10,15, 20-tetra (3, 5-dichlorophenyl) cobalt porphyrin (II), 5,10,15, 20-tetra (2,3,4,5, 6-pentafluorophenyl) cobalt porphyrin (II), 5,10,15, 20-tetra (2-chlorophenyl) cobalt porphyrin (II), 5,10,15, 20-tetra (4-methoxycarbonylphenyl) cobalt porphyrin (II), 5,10,15, 20-tetra (2-nitrophenyl) cobalt porphyrin (II) or 5,10,15, 20-tetrakis (4-fluorophenyl) porphyrin cobalt (II);

the arene containing the benzyl secondary C-H bond is a mixture of at least one or more than two of the formula (II), the formula (III) and the formula (IV) in any proportion:

wherein R is₁，R₂，R₃，R₄，R₅Each independently is: hydrogen, methyl, ethyl, propyl, butyl, isopropyl, tert-butyl, phenyl, 1-naphthyl, 2-naphthyl, methoxy, ethoxy, hydroxy, mercapto, amino, methylamino, ethylamino, dimethylamino, 1-hydroxyethyl, nitro, cyano, carboxy, benzyl, methoxycarbonyl, fluoro, chloro, bromo, or iodo.

2. The method of claim 1, wherein the metalloporphyrin is used for catalyzing and oxidizing aromatic hydrocarbons with benzyl secondary C-H bonds to aromatic ketones, and the ratio of the quantity of the metalloporphyrin to the quantity of the aromatic hydrocarbons with benzyl secondary C-H bonds is 1: 100000-1: 1000.

3. the method for catalytic oxidation of aromatic hydrocarbon benzylic secondary C-H bonding to aromatic ketone by metalloporphyrin as claimed in claim 1 or 2, wherein the stirring speed is 600-1200 rpm.

4. The method for catalytic oxidation of aromatic hydrocarbon benzyl-position secondary C-H bonding to aromatic ketone by metalloporphyrin as claimed in claim 1 or 2, wherein the reaction temperature is 100-120 ℃.

5. The method for catalytic oxidation of aromatic hydrocarbon benzylic secondary C-H bonding to aromatic ketone by metalloporphyrin as claimed in claim 1 or 2, wherein the reaction pressure is 0.6-1.2 MPa.

6. The method for catalytic oxidation of aromatic hydrocarbon benzylic secondary C-H bonding to aromatic ketone by metalloporphyrin as claimed in claim 1 or 2, wherein the reaction time is 8.0-16.0H.

7. The method for catalytic oxidation of aromatic hydrocarbon benzylic secondary C-H bonds to aromatic ketones by metalloporphyrin as claimed in claim 1 or 2, wherein said oxidant is oxygen, air or a mixture thereof in any proportion.

8. The method for catalytic oxidation of aromatic hydrocarbon benzyl-position secondary C-H bonding to aromatic ketone by metalloporphyrin as claimed in claim 1 or 2, wherein the method for post-treatment is as follows: after the reaction is finished, triphenylphosphine and triphenylphosphine PPh are added into the reaction solution₃The dosage of the compound is 1.0 to 25 percent of the amount of the aromatic hydrocarbon substance containing the benzylic C-H bond, the compound is stirred at room temperature for 30min to generate peroxide through reduction, and the crude product is distilled, rectified under reduced pressure and recrystallized to obtain an oxidation product.

Technical Field

The invention relates to a method for selectively oxidizing aromatic hydrocarbon benzyl secondary C-H bonding into aromatic ketone by using metalloporphyrin to catalyze molecular oxygen, belonging to the field of organic catalysis and fine organic synthesis.

Background

The catalytic oxidation of aromatic hydrocarbon benzyl secondary C-H bond is an important chemical conversion process, and the oxidation product aromatic ketone is a series of important and valuable oxygen-containing compounds which are widely used as basic raw Materials in the industries of essence, spice, medicine, pesticide, resin, dye and the like (WO 201611034971; Bioorganic & Medicinal Chemistry Letters 2019, 29: 525-. Currently, the synthesis of aromatic ketones is industrially carried out mainly by using ethylbenzene, 1-phenylethyl alcohol and styrene and derivatives thereof as raw materials and carrying out oxidation reaction (US 20190002487; CN 108947846; molecular Catalysis2019, 469: 27-39; Organic Process Research & Development 2019, 23: 825-835; ChemCat Chem 2019, 11: 1010-1016; Catalysis Communications2019, 122: 73-78; Catalysis Communications2019, 122: 52-57). Currently, the method generally adopted in industry is to directly oxidize the C-H bond at the benzyl position of aromatic hydrocarbon into aromatic ketone by using oxygen as an oxidant and metal salt as a catalyst. However, the method is usually carried out at a higher temperature, the energy consumption is high, the control is not easy, and the product is easy to deeply oxidize; meanwhile, the method also has the problems of large catalyst consumption, low catalyst recovery rate, use of corrosive solvents and auxiliaries and the like, so that the conventional aromatic ketone production process does not adapt to the urgent need of the chemical industry for green chemistry. Therefore, the development of a new method for catalytic oxidation of the benzylic secondary C-H bond of the aromatic hydrocarbon realizes the selective synthesis of the aromatic ketone by using a lower catalyst amount under the conditions of mild temperature, no solvent and no additive, and is an urgent need for the industrial synthesis of the aromatic ketone by catalytic oxidation of the benzylic secondary C-H bond of the aromatic hydrocarbon at present.

Metalloporphyrin is a transition metal complex with special catalytic performance, has excellent catalytic action on selective oxidation of hydrocarbon C-H bonds, and can show better catalytic performance at 1/1000000 of substrate amount (ChemSusChem 2019, 12: 684-. Because of low dosage, the metalloporphyrin does not need to be separated and recovered in the catalytic oxidation of the hydrocarbon, thereby simplifying the industrial separation process and having no obvious influence on the quality of the oxidation product, the production cost and the environment. In addition, the catalytic performance of the metalloporphyrin can be adjusted by changing the central metal and the peripheral substituent, and a huge catalyst selection object is provided for meeting the requirements of different catalytic performances.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a novel method for catalyzing and oxidizing aromatic hydrocarbon benzyl secondary C-H to be bonded into aromatic ketone by metalloporphyrin.

The technical scheme of the invention is as follows:

a method for metalloporphyrin-catalyzed oxidation of aromatic hydrocarbon benzylic secondary C-H bonds to aromatic ketones, said method comprising:

dispersing metalloporphyrin in aromatic hydrocarbon containing benzyl secondary C-H bonds, sealing a reaction system, heating to 80-150 ℃ (preferably 100-120 ℃) under stirring, introducing an oxidant to 0.20-2.0 MPa (preferably 0.6-1.2 MPa), keeping the set temperature and pressure, stirring for reaction for 3.0-24.0H (preferably 8.0-16.0H), and treating a reaction solution after the reaction is finished to obtain a product aromatic ketone;

the mass ratio of the metalloporphyrin to the aromatic hydrocarbon is 1: 1000000-1: 100, preferably 1: 100000-1: 1000, parts by weight;

the stirring speed is 100-1500 rpm, preferably 600-1200 rpm;

the oxidant is oxygen, air or a mixture of oxygen and air in any proportion.

The post-treatment method comprises the following steps: after the reaction, triphenylphosphine (PPh) was added to the reaction solution₃And the dosage is 1.0-25% of the amount of the aromatic hydrocarbon substance containing the benzylic C-H bond, the peroxide generated by reduction is stirred for 30min at room temperature (15-30 ℃), and the crude product is distilled, rectified under reduced pressure and recrystallized to obtain an oxidation product.

The method for analyzing the reaction result comprises the following steps: after the reaction is finished, peroxide generated by reduction of reaction liquid by triphenylphosphine is sampled and analyzed, acetone is used as a solvent for dilution, naphthalene is used as an internal standard for gas chromatographic analysis, the conversion rate of aromatic hydrocarbon and the selectivity of aromatic alcohol, aromatic ketone and peroxide are calculated, 2-naphthoic acid is used as an internal standard for liquid chromatographic analysis, and the selectivity of aromatic acid is calculated;

in the invention, the metalloporphyrin is at least one of the compounds shown in the formula (I):

in the formula (I), R₁、R₂、R₃、R₄、R₅Each independently is: hydrogen, methyl, ethyl, propyl, butyl, isopropyl, tert-butyl, phenyl, 1-naphthyl, 2-naphthyl, methoxy, ethoxy, hydroxy, mercapto, amino, methylamino, ethylamino, dimethylamino, 1-hydroxyethyl, nitro, cyano, carboxy, benzyl, methoxycarbonyl, fluoro, chloro, bromo, or iodo; m is Co²⁺、Mn²⁺、Ni²⁺、Fe²⁺、Cu²⁺Or Zn^{2 +}。

The metalloporphyrin is 5,10,15, 20-tetra (2,3, 6-trichlorophenyl) cobalt porphyrin (II), 5,10,15, 20-tetra (2, 6-dichlorophenyl) cobalt porphyrin (II), 5,10,15, 20-tetra (3, 5-dichlorophenyl) cobalt porphyrin (II), 5,10,15, 20-tetra (2,3,4,5, 6-pentafluorophenyl) cobalt porphyrin (II), 5,10,15, 20-tetra (2-chlorophenyl) cobalt porphyrin (II), 5,10,15, 20-tetra (4-methoxycarbonylphenyl) cobalt porphyrin (II), 5,10,15, 20-tetra (2-nitrophenyl) cobalt porphyrin (II) or 5,10,15, 20-tetrakis (4-fluorophenyl) porphyrin cobalt (II). The catalytic effect is better.

In the invention, the arene containing the benzyl secondary C-H bond is a mixture of at least one or more than two of the formulas (II), (III) and (IV) in any proportion:

wherein R is₁，R₂，R₃，R₄，R₅Each independently is: hydrogen, methyl, ethyl, propyl, butyl, isopropyl, tert-butyl, phenyl, 1-naphthyl, 2-naphthyl, methoxy, ethoxy, hydroxy, mercapto, amino, methylamino, ethylamino, dimethylamino, 1-hydroxyethyl, nitro, cyano, carboxy, benzyl, methoxycarbonyl, fluoro, chloro, bromo, or iodo.

The method takes metalloporphyrin as a catalyst, catalyzes oxygen to oxidize aromatic hydrocarbon benzyl secondary C-H bonds under the conditions of no solvent and no additive, realizes the high-efficiency and high-selectivity synthesis of aromatic ketone compounds under mild conditions, effectively avoids the use of toxic and harmful reagents, meets the social requirements of the current green chemical process, environment-friendly chemical process and biological compatibility chemical process, and has important application value. The invention also has certain reference value for the construction of other high-efficiency and high-selectivity catalytic oxidation systems.

The invention has the following beneficial effects: the method for selectively oxidizing aromatic hydrocarbon benzyl secondary C-H bonding into aromatic ketone by using metalloporphyrin to catalyze molecular oxygen has low reaction temperature, and effectively inhibits deep oxidation of target product aromatic ketone; no solvent or auxiliary agent is used, the operation process is simple, and the corrosion of equipment is low; the catalyst is low in consumption, does not need to be recycled, and simplifies the production operation process; the aromatic ketone has high selectivity and large industrial production application potential. The invention is a new method for synthesizing aromatic ketone by selective catalytic oxidation of aromatic hydrocarbon benzyl secondary C-H bond, which is efficient, feasible and safe.

Detailed Description

The invention will be further illustrated with reference to specific examples, without limiting the scope of the invention thereto.

Metalloporphyrins used in the present invention are described in Journal of the American Chemical Society2017, 139: 18590-18597; journal of the American Chemical Society 2018, 140: 6383 and 6390. All reagents used were commercially available analytical grade.