Synthesizing process of 2, 5-dichlorophenol

A technology for dichlorophenol and synthesis process, which is applied in the field of synthesis process of 2,5-dichlorophenol, can solve the problems of high industrialized production cost, environmental pollution, equipment corrosion, etc., and achieves reduction of the three-waste disposal amount and production cost. , the effect of short synthetic route

Inactive Publication Date: 2016-08-24
SICHUAN FOURSTAR BIOTECH RANDD CORP
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The process route is simple, but the separation of mixed dichlorophenol is difficult, and the industrial production cost is high; the patent US4326882 proposes to use 2,5-dichloroaniline as raw material, and prepare 2,5-dichloroaniline through diazotization and hydrolysis Phenol, this process is currently relatively mature 2,5-dichlorophenol synthesis process, its biggest disadvantage is serious environmental pollution, and the use of a large amount of inorganic acids and nitrites is also very serious for equipment corrosion; the patent US6586624 proposes to use 1 , 4-dichlorobenzene is used as raw material to directly carry out hydroxylation reaction with hydrogen peroxide to prepare 2,5-dichlorophenol. This process is a green process and conforms to atom economy, but the conversion rate of raw materials is very low, which is not suitable for large-scale industrial production

Method used

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  • Synthesizing process of 2, 5-dichlorophenol

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] A kind of synthetic technique of 2,5-dichlorophenol, comprises the following steps:

[0036] A. Halogenation

[0037] Dissolve 1,4-dichlorobenzene in an organic solvent, add catalyst, add bromine at 30°C, react for 10 hours, remove residual bromine in the system, separate the organic phase, and concentrate and rectify the organic phase to obtain 2,5 -Dichlorobromobenzene; the molar ratio of bromine and 1,4-dichlorobenzene is 0.5:1, 2,5-dichlorobromobenzene conversion rate is 92.5%;

[0038] B. Hydrolysis

[0039] Dissolve the 2,5-dichlorobromobenzene obtained in step A in an organic solvent, add a copper salt catalyst, an inorganic base and water, react for 1 hour at a temperature of 150°C and a pressure of 1 MPa, and then pass the reaction liquid through alkali After washing, acidifying, extracting, and precipitation treatment, 2,5-dichlorophenol is obtained; the molar ratio of the inorganic base to 2,5-dichlorobromobenzene is 2:1, and the water and 2,5- The molar r...

Embodiment 2

[0042] A kind of synthetic technique of 2,5-dichlorophenol, comprises the following steps:

[0043] A. Halogenation

[0044] Dissolve 1,4-dichlorobenzene in an organic solvent, add catalyst, add bromine at 50°C, react for 6 hours, remove residual bromine, separate the organic phase, concentrate and rectify the organic phase to obtain 2,5- Dichlorobromobenzene; the molar ratio of bromine to 1,4-dichlorobenzene is 0.7:1, and the conversion rate of 2,5-dichlorobromobenzene is 95.3%;

[0045] B. Hydrolysis

[0046] Dissolve the 2,5-dichlorobromobenzene obtained in step A in an organic solvent, add a copper salt catalyst, an inorganic base and water, react for 3 hours at a temperature of 210°C and a pressure of 2 MPa, and then pass the reaction solution through alkali After washing, acidifying, extracting, and solvent removal, 2,5-dichlorophenol is obtained; the molar ratio of the inorganic base to 2,5-dichlorobromobenzene is 5:1, and the water and 2,5- The molar ratio of dichlo...

Embodiment 3

[0050] A kind of synthetic technique of 2,5-dichlorophenol, comprises the following steps:

[0051] A. Halogenation

[0052] Dissolve 1,4-dichlorobenzene in an organic solvent. After adding the catalyst, add iodine at 40°C. After reacting for 9 hours, remove the residual iodine, and separate the organic phase. The organic phase is concentrated and rectified to obtain 2,5- Dichloroiodobenzene; the molar ratio of the iodine to 1,4-dichlorobenzene is 0.6:1, and the conversion rate of 2,5-dichloroiodobenzene is 93.8%;

[0053] B. Hydrolysis

[0054] Dissolve the 2,5-dichlorobromobenzene obtained in step A in an organic solvent, add a copper salt catalyst and an inorganic base, react for 3 hours at a temperature of 180°C and a pressure of 1.5 MPa, and then wash the reaction solution with alkali , acidification, extraction, precipitation treatment to obtain 2,5-dichlorophenol; the molar ratio of the inorganic base to 2,5-dichloroiodobenzene is 4:1; 2,5-dichlorophenol hydrolysis yi...

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Abstract

The invention discloses synthesizing process of 2, 5-dichlorophenol and belongs to the technical field of fine chemical industry. The synthesizing process includes halogenation and hydrolysis. The synthesizing process has the advantages that bromine or iodine which can be substituted more easily than chlorine is used, the bromine or iodine substituent group is hydrolyzed into hydroxyl after dichlorobenzene is halogenated, and halogenation depth is controlled by controlling the adding amount of the bromine or iodine so as to reduce the content of 2, 5-dichloro-1, 4-dihalogen benzene in the halogenation product; the conversion rate of 2, 5-dichloro halobenzene reaches above 92.0%, and the synthesizing process is short in synthetic route, simple, low in cost, few in produced three wastes and suitable for large-scale production.

Description

technical field [0001] The invention relates to a synthesis process of 2,5-dichlorophenol, which belongs to the technical field of fine chemicals. Background technique [0002] 2,5-Dichlorophenol is an important intermediate of pesticides, medicines, dyes, nitrogen fertilizer synergists and leather antifungal agents. The pure product of 2,5-dichlorophenol is a white needle-like crystal with a special odor, and is currently mostly used in the synthesis of the herbicide 3,6-dichloro-2-methoxybenzoic acid (dicamba). 3,6-dichlorosalicylic acid was synthesized from 2,5-dichlorophenol, followed by O-alkylation to prepare 3,6-dichloro-2-methoxybenzoic acid. 3,6-Dichloro-2-methoxybenzoic acid is a benzoic acid-based herbicide with the trade name of Dicamba, which is mainly used for the control of annual or perennial broad-leaved weeds in grass crop fields such as wheat. With the continuous deepening of research on dicamba-resistant biotechnology and dicamba mixed herbicides, its m...

Claims

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Application Information

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IPC IPC(8): C07C39/30C07C37/02
CPCC07C37/02C07C17/12
Inventor 何路涛李舟卢刚唐昊肖彦玲张华王蕾
Owner SICHUAN FOURSTAR BIOTECH RANDD CORP
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