Improved preparation technology of phloroglucinol

A technology of phloroglucinol and dichlorophenol, which is applied in the field of improved preparation process, can solve the problems of lower yield and quality, many influencing factors, harsh reaction conditions, etc., so as to reduce the cost of raw materials, shorten the process, and obtain raw materials easily Effect

Inactive Publication Date: 2006-06-14
NAN JING RHINE PHARM TECH
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  • Abstract
  • Description
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AI Technical Summary

Problems solved by technology

Using copper as a catalyst, under the condition of 170-175 ° C, replace the chlorine atom on the benzene ring with ammonia water to obtain triaminobenzene, add acid and hydrolyze to obtain phloroglucinol with a higher yield, but use high-pressure reaction equipment, The reaction conditions are relatively harsh
[0006] (3) Aniline method, starting from aniline, through bromination, deamination, methylation, demethylation five-step reaction (Mckillep A, Syn.Commun.1974, 4 (1): 35. Zhu Aishi, Xu Huaxin, Chinese Journal of Pharmaceutical Industry, 2000, 31(2): 80), the route is long, there are many influencing factors, the production process is not stable enough, and it is highly corrosive to equipment, especially the demethylation step requires a large volume of reaction Containers, making mass production infeasible
[0012] Its defect is also obvious: the reaction time is too long, and the mol ratio of potassium hydroxide and dichlorophenol is 9: 1, and this ratio is too large, causing the product to become brownish black due to oxidation and carbonization, which reduces the yield and quality, and at the same time It also increases the cost of water and electricity consumption for production

Method used

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Experimental program
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Effect test

Embodiment 1

[0027] In a 500ml three-necked flask (equipped with stirring and azeotropic water separator), 90g (1.62mol) of potassium hydroxide and 180ml of tetramethylbenzene were mixed, heated to slight reflux, and filled with nitrogen, so that the reactor was filled with nitrogen. A solution made of 90ml tetramethylbenzene and 32.6g (0.2mol) of 2,4-dichlorophenol was added dropwise, heated to 180-190°C and azeotropically refluxed to divide 6.6-7.2ml of water, and the reaction time was 2 hours. Cool to 140°C, add 100ml of water dropwise to the reaction solution, then cool to 40°C, separate tetramethylbenzene (which can be used in the next batch), acidify with 30% sulfuric acid to pH 3.5-4.0, a large amount of potassium sulfate is formed. Extract with 200ml×3 ethyl acetate, dry at 110°C, and remove crystal water to obtain about 28.0g of off-white solid phloroglucinol with a yield of 55.6% and a content (HPLC)≥98.8%.

Embodiment 2

[0029] In a 1000ml three-necked flask, mix 200g (4.0mol) of potassium hydroxide and 400ml tetramethylbenzene, reflux slightly, fill with nitrogen, add dropwise 200ml tetramethylbenzene and 65.2g (0.4mol) of 2,6-dichlorophenol to form The solution was heated to 180-190°C, 13-14ml of water was rapidly azeotropically separated, and the reaction time was 2 hours. All the other operations are the same as in Embodiment 1. About 56.7 g of the product phloroglucinol was obtained, the yield was 56.2%, and the content (HPLC) was greater than or equal to 98.0%.

Embodiment 3

[0031] In a 1000ml three-necked bottle, put 180g (3.24mol) of potassium hydroxide into it, mix it with 360ml of cumene and fill it with nitrogen, add it to slightly heated reflux, and dropwise add 180ml of cumene and 65.2g of 2,6-dichlorophenol ( 0.4mol) of the prepared solution was heated to 160-170°C, azeotropically refluxed for 10 hours, and 13-14ml of water was divided. All the other operations are the same as in Embodiment 1. 65.8 g of light yellow solid phloroglucinol was obtained, the yield was 65.2%, and the content (HPLC) was ≥98.5%.

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Abstract

The present invention relates to an improved preparation method for synthesizing phloroglucin. Said invention uses 2.4-dichlorophenol or 2.6-dichlorophenol as original raw material, and utilizes potassium hydroxide and inert solvent with high boiling point to make reaction of first-elimination after-addition to prepare phloroglucin by means of one-step process. Its yield is 56.6%-65.2%.

Description

field of invention [0001] The invention relates to the field of organic chemistry, in particular, the invention relates to a simple and practical improved preparation process for the synthesis of important pharmaceutical intermediate phloroglucinol. Background technique [0002] Phloroglucinol, also known as 1,3,5-trihydroxybenzene, English name: phloroglucinol, CAS: [108-73-6] (anhydrous), molecular formula: C 6 h 3 o 3 ;Molecular weight: 126.1. [0003] Since the 1960s, many methods for the synthesis of phloroglucinol have been reported, such as the trinitrotoluene method and the malonate method. At present, there are about four kinds of processes that can really be applied in industrial production: [0004] (1) The cumene method, using mesityl cumene as a raw material, undergoes two oxidations and one decomposition to obtain the target product phloroglucinol (Hooker Electrochemical Company. Meta-substituted phenols and method for their synthesis. GB751598, 1956 ), af...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C39/10C07C37/01
Inventor 陈新梅以成
Owner NAN JING RHINE PHARM TECH
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