Preparation of o-nitro p-methylsulfonylbenzoic acid

A technology of methylsulfonyl benzoic acid and o-nitro group, which is applied in the field of preparation of o-nitro-p-methylsulfonyl benzoic acid, can solve the problems of large amount of hydrogen peroxide, high production cost, easy decomposition and the like, and achieves reduction of waste liquid treatment and recycling , production cost reduction, the effect of cleaner production process

Active Publication Date: 2009-08-12
浙江嘉福新材料科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But the oxidation ability of hydrogen peroxide is weak, and it is easy to decompose. Generally, hydrogen peroxide is used as an oxidant in a large amount, so that hydrogen peroxide, a clean and environmentally friendly oxidant, cannot be used in many reactions.
For example, European patent WO 2004/058698 A1 introduces the process of obtaining o-

Method used

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  • Preparation of o-nitro p-methylsulfonylbenzoic acid

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preparation example Construction

[0013] The preparation method of this o-nitro-p-methylsulfonyl benzoic acid is to oxidize o-nitro-p-methylsulfone toluene with persulfuric acid to obtain o-nitro-p-methylsulfonyl benzoic acid, and its process is:

[0014] (a) hydrogen peroxide and oleum are mixed at low temperature to prepare persulfuric acid;

[0015] (b) dissolving o-nitro-p-methylsulfone toluene in 70% sulfuric acid;

[0016] (c) adding the persulfuric acid obtained in step a dropwise to the liquid obtained in step b, and the reaction obtains o-nitro-p-methylsulfonyl benzoic acid. After cooling, crystals were precipitated, and the product was obtained by suction filtration.

[0017] In the preparation method of this o-nitro-p-methylsulfonyl benzoic acid, in step a, the concentration of oleum is 20-60% by weight, and the concentration of hydrogen peroxide is 50% by weight; the concentration of sulfuric acid used in step b is 70% weight percent concentration; the amount that each raw material adds in the re...

Embodiment 1

[0028] 1. Preparation of persulfuric acid:

[0029] Place 25.5g of fuming sulfuric acid with a concentration of 60% (weight percent concentration, the same in the future) in a 100mL three-necked round-bottomed flask, under magnetic stirring, slowly add 25.5g of concentration 50% (weight percent concentration, all the same hereafter) H 2 O 2 (0.375mol), the temperature of the ice bath was controlled below 30°C, and the stirring was continued for 15 minutes after the completion of the dropwise addition.

[0030] 2. Preparation of o-nitro-p-methylsulfonyl benzoic acid:

[0031] 5.4g (0.025mol) of o-nitro-p-methylsulfone toluene and 37.6g of 70% H 2 SO 4 The reaction flask was added and the reaction mixture was heated to 80°C. Slowly add 51 g of persulfuric acid prepared in the previous step to the mixed solution dropwise within 4 to 5 hours, control the reaction temperature to 80-100°C during the dropwise addition, cool down to 6°C after the reaction, and obtain ortho-nitrat...

Embodiment 2

[0033] 1. Preparation of persulfuric acid:

[0034] Put 20.0g of 50% oleum in a 100mL three-necked round-bottomed flask, and slowly add 15.3g of 50% H into it dropwise under magnetic stirring. 2 O 2 (0.225mol), the temperature of the ice bath was controlled to be below 30°C, and the stirring was continued for 15 minutes after the dropwise addition, and it was set aside.

[0035] 2. Preparation of o-nitro-p-methylsulfonyl benzoic acid:

[0036] 5.4g (0.025mol) of o-nitro-p-methylsulfone toluene and 37.6g of 70% H 2 SO 4 The reaction flask was added and the reaction mixture was heated to 80°C. 35.3 g of persulfuric acid prepared in the previous step was slowly added dropwise to the mixed solution within 4 to 5 hours, and the reaction temperature was controlled to 80-130°C during the dropwise addition. Nitro-p-methylsulfonylbenzoic acid is 4.3 g of white solid, the yield is 70.0%, and the content by liquid chromatography analysis is 91%.

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Abstract

The invention relates to a preparation method of o-nitro-p-methysulfonyl benzoic acid. O-nitro-p-methylsulfonyl toluene is oxidized by persulphuric acid to obtain the o-nitro-p-methysulfonyl benzoic acid. The preparation method comprises the following processes: (a) oxyful and oleum are mixed at a low temperature to prepare persulphuric acid; (b) o-nitro-p-methylsulfonyl toluene is dissolved in sulphuric acid; and (c) the persulphuric acid obtained from the step (a) is dripped into the liquid obtained from the step (b) for purpose of reaction to obtain the o-nitro-p-methysulfonyl benzoic acid. In the method, the reaction of the oleum and the oxyful relatively improves the concentration and the oxidization capability of the oxyful and reduces the decomposition speed of the oxyful; as vanadic oxide is not used, waste acid treatment, recovery and the like are omitted; and the persulphuric acid in use is automatically transformed into sulphuric acid after the oxidization is finished and can finally be used indiscriminately with a mother liquid. Compared with the prior art, the amount of the oxyful in use is greatly reduced, and the production cost remarkably decreases. Compared with the nitric acid oxidization process, the preparation method is safer, environment-friendly and clean.

Description

technical field [0001] The invention relates to a preparation method of o-nitro-p-methylsulfonyl benzoic acid, and belongs to the field of organic chemistry. Background technique [0002] Ortho-nitro-p-methylsulfonylbenzoic acid is an important organic intermediate. The preparation of this type of benzoic acid containing multiple electron withdrawing groups is usually obtained by oxidizing toluene of corresponding substituents with nitric acid, a strong oxidant. Since toluene containing electron withdrawing groups is difficult to oxidize, it can only be carried out under the catalysis of vanadium pentoxide. For example, United States Patent 5,424,481 introduces a method for oxidizing o-nitro-p-methylsulfonyl benzoic acid with nitric acid under the catalysis of vanadium pentoxide. The product has a purity of over 90% and a yield of over 80%. Although this method has a relatively high yield, the nitrogen dioxide gas generated during the oxidation of nitric acid pollutes the e...

Claims

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Application Information

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IPC IPC(8): C07C317/44C07C315/04
Inventor 吴建一王宏亮宗乾收缪程平周幼红向自伟邹玲
Owner 浙江嘉福新材料科技有限公司
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