A kind of preparation method of 2-nitro-4-methylsulfonyl benzoic acid

Abstract

The invention provides a preparation method of 2-nitryl-4-methanesulfonyl-benzoic acid. The preparation method takes 2-nitryl-4-methylsulfonyl toluene as a starting raw material, aliphatic carboxylicacid as a solvent, one or more N-hydroxylamine compounds as a catalyst, one or more of nitric acid, nitrate or nitrite as a co-catalyst, and molecular oxygen as a catalyst to react for 0.5 to 15h under the conditions that the pressure is 0.1 to 5MPa and the temperature is 60 to 180 DEG C, so as to obtain 2-nitryl-4-methanesulfonyl-benzoic acid. According to the method provided by the invention, the defects of an existing industrial production method of 2-nitryl-4-methanesulfonyl-benzoic acid that the amount of three wastes is great, equipment is seriously corroded and the like are overcome andclean production of 2-nitryl-4-methanesulfonyl-benzoic acid is easy to realize.

Description

technical field [0001] The invention relates to a preparation method of 2-nitro-4-thiamphenicol benzoic acid. Background technique [0002] 2-nitro-4-thiamphenicol benzoic acid is an important intermediate in the synthesis of mesotrione, which is an excellent herbicide and has been widely used worldwide. In addition, 2-nitro-4-thiamphenicol benzoic acid is also widely used in dyestuffs, medicine and other industries, and its synthesis has received extensive attention. [0003] The synthesis of 2-nitro-4-thiamphenicol benzoic acid has multiple methods, which are divided into according to different starting materials: (1) hydrolysis method: CN200910091467 discloses a hydrolysis of 2-nitro-4-thiamphenicol benzene Nitrile prepares 2-nitro-4-thiamphenicol benzoic acid, but the raw material is not easy to obtain and the price is relatively expensive, and is not suitable for industrialized production; (2) oxidation method: due to the aromatic ring of 2-nitro-4-thiamphenicol toluen...

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Problems solved by technology

[0003] The synthesis of 2-nitro-4-thiamphenicol benzoic acid has multiple methods, which are divided into according to different starting materials: (1) hydrolysis method: CN200910091467 discloses a hydrolysis of 2-nitro-4-thiamphenicol benzene Nitrile prepares 2-nitro-4-thiamphenicol benzoic acid, but the raw material is not easy to obtain and the price is relatively expensive, and is not suitable for industrialized production; (2) oxidation method: due to the aromatic ring of 2-nitro-4-thiamphenicol toluene There are two strong electron-withdrawing groups attached to it, which makes it difficult to oxidize the methyl group on the aromatic ring, so the oxidation requires the use of stronger oxidants and catalysts to accelerate the reaction.

This method has mild oxidation conditions and high yield, but it will produce heavy metal pollution and is not environmentally friendly; (ii). Nitric acid oxidation: CN201510133705 and others disclose that nitric acid is used as an oxidant, and vanadium pentoxide is commonly used as a catalyst to realize oxidation.

This method is also the main method used in industrial production at present. The advantage of this method is that nitric acid is cheap and easy to get but can produce a large amount of waste acid, and the catalyst is highly toxic, and the pressure on environmental protection is large; (iii). Peroxide oxidation: CN201110001352 reported the use of Hydrogen peroxide is used as oxidant, and hydrogen peroxide is more green and environment-friendly as oxidant, but its consumption is large, and yield is lower; (iv). Oxygen / air oxidation: for example, patent US5591890 has reported that cobalt acetate is used as catalyst, and air is oxidant; CN201110288563 uses metalloporphyrin Prepare 2-nitro-4-thiamphenicol benzoic acid for catalyst, but these methods have low oxidation ability, problems such as poor oxidation effect

[0004] On the whole, in the synthetic method of existing 2-nitro-4-thiamphenicol benzoic acid, prepare 2-nitro-4-thiamphenicol benzoic acid with oxidation 2-nitro-4-thiamphenicol toluene The process generally has defects such as large amount of three wastes, poor selectivity, and high production cost.

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