Improved method for preparing aromatic ketone

Abstract

The invention relates to an improved method for preparing aromatic ketone, which is characterized in that: in the presence of iron sesquioxide catalyst, benzene or substituted benzene and acid anhydride are reacted to prepare the aromatic ketone, wherein the substituted benzene refers to a benzene molecule ring on which one hydrogen atom or two hydrogen atoms is / are substituted by a substituted group, and the substituted group is alkyl, hydroxy or methyl ether group containing 1 to 7 carbons; and the prepared aromatic ketone is mixed aromatic ketone, one single bond of the carbonyl of the aromatic ketone is connected with the alkyl containing 1 to 4 carbons, while the other single bond is connected with the benzene or the substituted benzene. The reaction temperature is between 60 and 150 DEG C; the molar ratio of the benzene or the substituted benzene to the iron sesquioxide catalyst is 1: 0.0001-0.005; and the molar ratio of the benzene or the substituted benzene to the acid anhydride is 1: 0.5-2. The using amount of the iron sesquioxide is far less than that of aluminum chloride in the prior art, the reaction condition is mild, the method does not need to strictly isolate air,the product has good color and texture, the post treatment is simple, and the preparation process does not produce hydrogen chloride and is a green chemical process.

Description

technical field [0001] The present invention relates to an improved process for the preparation of aromatic ketones. Background technique [0002] As we all know, aromatic ketones, as important chemical products and intermediates, are widely used in medicine, pesticides, dyes and other fields. There are many known preparation methods of aromatic ketones, among which the method of preparing aromatic ketones by Friedel-Crafts acylation is widely used because the reaction proceeds smoothly and quickly, and the yield is also good. The acylating agent usually used in this method is acid chloride or acid anhydride, and carboxylic acid can also be used in special cases. The most effective catalyst used was anhydrous aluminum trichloride. However, when acid chlorides are used, the by-product hydrogen chloride is easily produced, which seriously pollutes the environment. However, the production rate of using acid anhydride as an acylating agent is relatively high, and the pollution...

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Problems solved by technology

However, when acid chlorides are used, the by-product hydrogen chloride is easily produced, which seriously pollutes the environment. However, the production rate of using acid anhydride as an acylating agent is relatively high, and the pollution to the environment is relatively small. However, due to the use of aluminum trichloride as a catalyst, the method exists The following disadvantages: ①The aluminum trichloride catalyst is easy to hydrolyze, releasing three times hydrogen chloride, causing serious pollution; ②The aluminum trichloride catalyst can complex with acid anhydride and aromatic ketone products, so the amount is huge, usually 2-3 times the amount of benzene replaced 3 times or more, resulting in a very serious waste of raw materials; ③ the complex produced by the aluminum trichloride catalyst and the product aromatic ketone makes the post-treatment process complicated; ④ the yellow by-product generated by the reaction of the aluminum trichloride catalyst and the acid anhydride and the product aromatic ketone Miscibility makes the separation of the two very difficult, which affects the purity of the aromatic ketone product, which in turn affects the application of the aromatic ketone as an intermediate

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