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Preparation method of methylene blue

A technology of methylene blue and nitroso, applied in the direction of organic chemistry, can solve the problems of cumbersome feeding process and unfavorable industrial production, and achieve the effect of simple process flow, low environmental pollution and high purity

Active Publication Date: 2015-12-09
JIANGSU HERUN PHARMA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the reaction process, it is necessary to use manganese dioxide, sodium dichromate or hydrogen sulfide, which seriously pollute the environment, for oxidation, and the feeding process is cumbersome, which is not conducive to industrial production

Method used

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  • Preparation method of methylene blue

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] 1. Preparation of p-nitroso-N,N-dimethylaniline (3)

[0056] In a 1000mL four-necked bottle, add 116.5g of 36% HCl and 81g of water, stir and cool down to 0-5°C, slowly add 58g of N,N-dimethylaniline dropwise, exothermic during the dropwise addition, the temperature must be strictly controlled for 5 Below ℃, the dropwise addition is completed, stir for 15 minutes, and start to dropwise add a solution of 36.33g sodium nitrite and 113g water. The dropwise exotherm is severe, and the dropping process must be strictly controlled at 0-5°C, and the dropping time is 4-5 hours. , the dropwise addition is completed, and the system temperature is 0-5° C. for 1 h. Filter to remove the mother liquor of hydrochloric acid to obtain solid p-nitroso-N,N-dimethylaniline hydrochloride. In a 1000ml four-necked bottle, add the above-mentioned p-nitroso-N,N-dimethylaniline hydrochloride, 150g toluene and 180g purified water, stir mechanically, start adding 45g aqueous solution of 15g sodiu...

Embodiment 2

[0068] 1. Preparation of p-nitroso-N,N-dimethylaniline (3)

[0069] In a 1000mL four-necked bottle, add 116.5g of 36% HCl and 81g of water, stir and cool down to 0-5°C, slowly add 58g of N,N-dimethylaniline dropwise, exothermic during the dropwise addition, the temperature must be strictly controlled for 5 Below ℃, the dropwise addition is completed, stir for 15 minutes, and start to dropwise add a solution of 36.33g sodium nitrite and 113g water. The dropwise exotherm is severe, and the dropping process must be strictly controlled at 0-5°C, and the dropping time is 4-5 hours. , the dropwise addition is completed, and the system temperature is 0-5° C. for 1 h. Filter to remove the mother liquor of hydrochloric acid to obtain solid p-nitroso-N,N-dimethylaniline hydrochloride. In a 1000ml four-necked bottle, add the above-mentioned p-nitroso-N,N-dimethylaniline hydrochloride, 150g of dichloromethane and 180g of purified water, stir mechanically, start to add 45g of aqueous solu...

Embodiment 3

[0080] 1. Preparation of p-nitroso-N,N-dimethylaniline (3)

[0081] In a 1000mL four-necked bottle, add 116.5g of 36% HCl and 81g of water, stir and cool down to 0-5°C, slowly add 58g of N,N-dimethylaniline dropwise, exothermic during the dropwise addition, the temperature must be strictly controlled for 5 Below ℃, the dropwise addition is completed, stir for 15 minutes, and start to dropwise add a solution of 36.33g sodium nitrite and 113g water. The dropwise exotherm is severe, and the dropping process must be strictly controlled at 0-5°C, and the dropping time is 4-5 hours. , the dropwise addition is completed, and the system temperature is 0-5° C. for 1 h. Filter to remove the mother liquor of hydrochloric acid to obtain solid p-nitroso-N,N-dimethylaniline hydrochloride. In a 1000ml four-necked bottle, add the above-mentioned p-nitroso-N,N-dimethylaniline hydrochloride, 150g ethyl acetate and 180g purified water, stir mechanically, start to add 45g aqueous solution of 15g...

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Abstract

The invention discloses a preparation method of methylene blue, and belongs to the technical field of intermediate synthesis in fine chemical engineering. The preparation method comprises the following steps: in a condensed hydrochloric acid solution, carrying out nitrosation reactions between sodium nitrite and N,N-dimethylaniline so as to obtain an intermediate namely p-nitroso-N,N-dimethylaniline; subjecting p-nitroso-N,N-dimethylaniline to hydrogenation reduction to prepare p-amino-N,N-dimethylaniline; oxidizing p-amino-N,N-dimethylaniline, then adding sodium thiosulfate to carry out addition reactions to prepare 2-amino-5-dimethylaminophenyl thiosulfonic acid, adding N,N-dimethylaniline into 2-amino-5-dimethylaminophenyl thiosulfonic acid to carry out oxidative condensation reactions to generate bis(4-dimethylaminophenyl) thiosulfonic acid; and making bis(4-dimethylaminophenyl) thiosulfonic acid carry out ring-closing reactions to obtain methylene blue. The provided preparation method has the advantages of high product purity, simple technology flow, low manufacture cost, suitability for industrial production, easily-available raw materials, and little pollution to the environment.

Description

Technical field: [0001] The invention belongs to the technical field of synthesis of fine chemical intermediates, and in particular relates to a preparation method of methylene blue. Background technique: [0002] Methylene blue (as shown in formula (1)), the molecular weight is 319.86, the English name is methyleneblue, and the chemical name is 3,7-bis(dimethylamino)phenothiazin-5-ium chloride, which is a phenothiazine salt . It was first synthesized in the form of zinc chloride salt by German chemist Heinrich Caro in 1876. Methylene blue is widely used in chemical indicators, dyes, biological stains and drugs. [0003] At present, there are mainly following four methods for the preparation of methylene blue reported in the literature: [0004] Method 1: The synthesis method provided in the patent of CN200610201306.9 is to use N,N-dimethylaniline as raw material, oxidize manganese dioxide and replace with sodium thiosulfate to obtain 2-amino-5-dimethylaminobenzene The l...

Claims

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Application Information

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IPC IPC(8): C07D279/20
CPCC07D279/20
Inventor 史荣先韩冬李安排戴燕吴正华徐勇顾兴华赵小华钟章春
Owner JIANGSU HERUN PHARMA CO LTD
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