A preparing method of p-nitroacetophenone

Abstract

A preparing method of p-nitroacetophenone is disclosed. The method includes reacting p-nitroethylbenzene, as a raw material, in an autoclave at 110-150 DGE C for 3-7 h under the function of a metalloporphyrin catalyst shown as a formula 1 or a formula 2 in an oxygen atmosphere having a pressure of 0.8-2 MPa under a condition of no solvent; and subjecting an obtained reaction liquid mixture to after-treatment to obtain the target product that is p-nitroacetophenone. The method includes reaction in the sealed autoclave, thus greatly reducing volatilization loss of the raw material, and avoidingemission of reaction waste gas so as to avoid environment pollution therefrom. The bionic metalloporphyrin catalyst which is naturally degradable is adopted as an auxiliary catalyst, is low in dosage,and can increase product selectivity. Consumption of an organic solvent and purification of the target product are avoided, thus reducing the cost.

Description

(1) Technical field [0001] 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. (2) Background technology [0002] 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, 58, 9879) are h...

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Problems solved by technology

[0004] (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.

[0011] (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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