A kind of preparation method of p-nitroacetophenone

Abstract

The invention discloses a preparation method of p-nitroacetophenone. The method is specifically carried out according to the following steps: using p-nitroethylbenzene as a raw material, under the action of a metalloporphyrin catalyst represented by formula 1 or formula 2 , under an oxygen atmosphere of 0.8-2MPa, under solvent-free conditions, in an autoclave, react at 110-150°C for 3‑7h, and the obtained reaction mixture is post-processed to obtain the target product nitroacetophenone. The method of the present invention reacts in a closed autoclave, which can greatly reduce the volatilization loss of raw materials, and can also avoid the discharge of reaction waste gas, and avoid the resulting environmental pollution problems; the bionic catalyst metal porphyrin that can be naturally degraded is adopted. The morphine is an auxiliary catalyst, and the dosage is small, which can improve the selectivity of the product; avoid the consumption of the organic solvent and the purification of the target product, and reduce the cost.

Description

[0001] (1) Technical field [0002] The invention relates to the preparation of aromatic ketones, in particular to a method for preparing p-nitroacetophenone by bionic catalyzing oxygen oxidation of p-nitroethylbenzene. [0003] (2) Background technology [0004] p-Nitroacetophenone is an important organic synthesis intermediate widely used in medicine (Bioorganic & Medicinal Chemistry Letters, 2010, 20, 4168), pesticides (Bioorganic & Medicinal Chemistry Letters, 2010, 20, 4693), dye synthesis and other fields. In the preparation process of p-nitroethylbenzene, since the functional group (nitro, acetyl) of p-nitroethylbenzene belongs to the meta-positioning group, the nitration of nitrobenzene and acetophenone to prepare the target product It is relatively difficult, so most of them use the method of selective oxidation of the benzylic C-H bond of the aryl side chain to prepare the target product, and the oxidant is mainly KMnO 4 、H 2 o 2 , t-BOOH, etc. (Tetrahedron, 2002, ...

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Problems solved by technology

[0006] (2) CN 102532200 A (publication date: July 4, 2012) discloses the synthesis and application of an N,N-coordinated dimeric rhodium (II) complex, which is oxidized in the benzylic position Show good activity, this method uses above-mentioned complex 1.0mol% as catalyzer, oxidant is 4.0 equivalent tert-butyl hydroperoxide aqueous solution, water is as solvent, reacts at room temperature for 20 hours, can obtain the yield of 82% p- Nitroacetophenone, the advantage of this method is that the reaction conditions are mild, the yield is high, and water is the solvent. The disadvantage is that a specific catalyst is required, and the concentration of the substrate is small, so it is difficult to achieve scale-up and industrial production

The disadvantage of this method is to carry out high-temperature initiation, and the temperature is high. During the process of using oxygen bubbling, the loss of oxygen is large, which is uneconomical.

[0013] (9) Katsuhiko Moriyama (Organic Letters, 2012, 14, 2414) et al reported the use of free radical initiator KBr (1.5eq.), using visible light to selectively catalyze the oxidation of the C-H bond at the benzylic position of aromatic hydrocarbons, Oxone (1.2eq. ) is the most oxidizing agent, using solvent CH 2 Cl 2 -H 2 O(9:1), reaction at room temperature for 24 hours, the yield of p-nitroacetophenone can reach 96%. The disadvantage of the modified method is that the amount of reaction substrate is small, and it is difficult to scale up to realize industrial production.

The advantages of the new process are atmospheric pressure oxidation, high product yield, and reduced tail gas, which is suitable for industrial production; the disadvantage is that the amount of catalyst used is relatively large, and it pollutes the environment and the production cost is high.

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