Preparation method of p-nitroacetophenone

Abstract

The invention discloses a preparation method of p-nitroacetophenone. The method is concretely performed according to the following steps: taking nitroethylbenzene as a raw material, reacting for 6h at110-150 DEG C in an autoclave and a solvent-free condition in an oxygen atmosphere of 0.8-2.0MPa under the action of a metalloporphyrin catalyst, and enabling obtained reaction mixture to be subjected to post-treatment to obtain a target product nitroacetophenone. The method disclosed by the invention is used for performing reaction in the closed autoclave, the volatilization loss of raw materials can be greatly reduced, the discharge of reaction exhaust gas can be avoided as well, and the environmental pollution problem caused by the discharge is avoided; according to the technology, a solvent is not required in the whole oxidation process, the consumption of an organic solvent and the environmental problem caused by the consumption are avoided, the production cost is lowered, and the production efficiency is improved.

Description

(1) Technical field: [0001] The technology relates to a preparation method of p-nitroacetophenone. (two) background technology: [0002] p-Nitroacetophenone is an important organic synthesis intermediate widely used in medicine (Bioorganic & Medicinal Chemistry Letters, 2010, 20, 4168), pesticide (Bioorganic & Medicinal Chemistry Letters, 2010, 20, 4693), dye synthesis and other fields . In the process of producing p-nitroacetophenone, since the functional group (nitro, acetyl group) of p-nitroethylbenzene belongs to the meta-positioning group, the nitration of nitrobenzene and the nitration of acetophenone to prepare the target The product 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 highly oxidizing chemical reagents. The catalysts often use manganese acetate, cobalt a...

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Problems solved by technology

[0004] (2) CN 102532200A (public date: July 4, 2012) discloses the synthesis and application of a complex involving N,N-coordinated dimeric rhodium (II), which exhibits Good activity, the method uses 1.0mol% of the above-mentioned complex as a catalyst, the oxidant is 4.0 equivalents of tert-butyl hydroperoxide aqueous solution, water is used as a solvent, and reacts at room temperature for 20 hours to obtain p-nitrogen with a yield of 82%. The advantage of this method is that the reaction conditions are mild, the yield is high, and water is used as 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), react at room temperature for 24 hours, and the yield of p-nitroacetophenone can reach 96%.

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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