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Preparation method of 6-nitrosaccharin

A technology of nitrosaccharin and nitrobenzoic acid, applied in the field of preparation of 6-nitrosaccharin, can solve the problems of difficulty in industrialization, serious environmental pollution, difficult control, etc., and achieves low price, no environmental pollution and low production cost Effect

Active Publication Date: 2011-11-23
江苏省农用激素工程技术研究中心有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This process has the disadvantages of severe reaction, difficult to control, serious environmental pollution, and difficulty in industrialization.

Method used

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  • Preparation method of 6-nitrosaccharin

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] The preparation method of 6-nitrosaccharin of this embodiment has the following steps:

[0020] ①Preparation of methyl 2-amino-4-nitrobenzoate: Add 40g of 2-amino-4-nitrobenzoic acid and 300ml of methanol (237g) into a 500ml four-necked flask as the reactants, and add 54g of Thionyl chloride is used as an acid catalyst to generate a reaction of 2-amino-4-nitrobenzoic acid methyl ester. The reaction slowly exotherms to boiling, and the reaction is heated and refluxed for 10 hours after dropping. After the completion of the reaction, vacuum was applied under reduced pressure to evaporate the methanol, and the methanol was recovered. The remaining concentrate was dissolved by adding 300 ml of ethyl acetate, and the resulting mixture was washed with a saturated aqueous sodium bicarbonate solution until neutral. Heat the entire system to evaporate the water, continue heating to evaporate the ethyl acetate and concentrate the organic phase to make the product precipitate. After ...

Embodiment 2

[0025] The preparation methods of Example 2 to Example 3 are basically the same as that of Example 1, except that the acid catalyst used in step ① is different. The acid catalyst used in Example 2 is concentrated sulfuric acid (98wt%). Example 3 The acid catalyst used is gaseous hydrogen chloride. The method for adding concentrated sulfuric acid in Example 2 is dropwise addition, and the method for adding gaseous hydrogen chloride in Example 3 is to pass the gaseous hydrogen chloride into the reaction system. See Table 1 for details.

[0026] Table 1

[0027] Acid catalyst

Embodiment 4 to Embodiment 8

[0029] The preparation methods of Example 4 to Example 8 are basically the same as that of Example 1, except that the acidic medium and diazotization temperature used in step ② are different. See Table 2 for details.

[0030] Table 2

[0031] Acid medium

[0032] It can be seen from Table 2 that the yield at the reaction temperature of 10°C to 15°C is higher than other temperatures. On the other hand, the acidic medium is different, and the reaction effect is also different. Using hydrochloric acid as the reaction medium is better than other reaction media.

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Abstract

The invention discloses a preparation method of 6-nitrosaccharin, which comprises the following steps of: adding 2-amino-4-nitrobenzoic acid into excessive methanol for carrying out reflow esterification under the catalysis of an acidic catalyst to obtain 2-amino-4-nitro methyl benzoate through postprocessing; carrying out diazotization reaction on the 2-amino-4-nitro methyl benzoate and a sodiumnitrite solution in an acidic medium under the temperature of 0-20 DEG C; then adding a glacial acetic acid solution of copper chloride into a system under the temperature of 20-30 DEG C to generate 2-chloro sulfonyl-4-nitro methyl benzoate; and reacting the 2-chloro sulfonyl-4-nitro methyl benzoate with ammonia water under the temperature of 0-40 DEG C to obtain the 6-nitrosaccharin. The method has simple reaction operation, no environment pollution, wide sources and low cost of the 2-amino-4-nitrobenzoic acid as the raw material, lower production cost and suitability for industrialized production.

Description

Technical field [0001] The invention relates to a preparation method of organic chemical intermediates, in particular to a preparation method of 6-nitrosaccharin. Background technique [0002] 6-Nitrosaccharin is an important chemical intermediate with a wide range of applications. It can be used in the synthetic chemical fiber industry as well as in the pesticide industry. It is an important intermediate for the synthesis of the herbicide iodosulfuron-methyl sodium salt and formamisulfuron-methyl. [0003] US patent US3158233 discloses a method for obtaining 6-nitrosaccharin by oxidation reaction with 4-nitrotoluene-2-sulfonamide as raw material and sodium dichromate. This process has disadvantages such as severe reaction, difficult to control, serious environmental pollution, and difficulty in industrialization. Summary of the invention [0004] The purpose of the present invention is to overcome the above-mentioned problems and provide a method for preparing 6-nitrosaccharin wh...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D275/06
Inventor 孔繁蕾王智敏
Owner 江苏省农用激素工程技术研究中心有限公司
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