Synthesis method of 2,4,6-trimethyl-m-phenylenediamine

A technology of trimethyl m-phenylenediamine and trimethyl, applied in the field of synthesis 2, can solve the problems of high production cost, many reaction steps, and high hydrogenation reduction pressure, and achieves reduction in raw material cost, stable product quality, and high reaction steps. less effect

Inactive Publication Date: 2016-04-06
JIANGSU TIANJIAYI CHEM CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

There are following problems in adopting this synthetic route: (1) many reaction steps; (2) the hydrogenation reduction pressure is as high as 5-7.5 MPa; (3) the hydrogenation reduction catalyst is easily deactivated, and the service life of the catalyst is short; (4) the yield Low (total recovery has only 65%), high production cost; (5) environmental pollution is big, and product purity is low (only 97%), and unstable

Method used

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  • Synthesis method of 2,4,6-trimethyl-m-phenylenediamine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Add 114kg of mesitylene in 1000L nitration kettle with coil cooling, open and stir and add 700kg of mixed acid dropwise (mixed acid is H 2 SO 4 and HNO 3 of mixed acids, H 2 SO 4 and HNO 3 The weight ratio is 80.4:19.6), the reaction temperature is controlled at 55°C, and the drop is maintained for 30 minutes, the temperature is raised to 95°C, maintained for 30 minutes, the stratification is allowed to stand, and the waste acid is applied to the next batch of nitration reaction. Add 500 kg of water and 2 kg of caustic soda to the organic layer, stir for 1 hour and let it stand for stratification, then add 500 kg of water, and wash with water to obtain 2,4,6-trimethyl-m-dinitrobenzene.

[0018] Add the above-mentioned 2,4,6-trimethyl-m-dinitrobenzene to a 1000L liter autoclave, then add 10kg of Ni catalyst, 320kg of methanol, and replace with nitrogen and hydrogen. Start stirring and heat up to 60°C, start hydrogenation, control hydrogenation pressure 1-3MPa, tempe...

Embodiment 2

[0020] Add 114kg of mesitylene in 1000L nitration kettle with coil cooling, open and stir and add 700kg of mixed acid dropwise (mixed acid is H 2 SO 4 and HNO 3 of mixed acids, H 2 SO 4 and HNO 3 The weight ratio is 75:25), the reaction temperature is controlled at 20°C, the dripping is completed and maintained for 35 minutes, the temperature is raised to 90°C, maintained for 35 minutes, the stratification is allowed to stand, and the waste acid is applied to the next batch of nitration reaction. Add 500 kg of water and 2 kg of caustic soda to the organic layer, stir for 1 hour and let it stand for stratification, then add 500 kg of water, and wash with water to obtain 2,4,6-trimethyl-m-dinitrobenzene.

[0021] Add the above-mentioned 2,4,6-trimethyl-m-dinitrobenzene to a 1000L liter autoclave, then add 10kg of Ni catalyst, 320kg of methanol, and replace with nitrogen and hydrogen. Start stirring and heat up to 65°C, start hydrogenation, control hydrogenation pressure 4MP...

Embodiment 3

[0023] Add 114kg of mesitylene in 1000L nitration kettle with coil cooling, open and stir and add 700kg of mixed acid dropwise (mixed acid is H 2 SO 4 and HNO 3 of mixed acids, H 2 SO 4 and HNO 3 The weight ratio is 87:13), the reaction temperature is controlled at 100°C, the dripping is completed and maintained for 30 minutes, the temperature is raised to 90°C, maintained for 30 minutes, the stratification is allowed to stand, and the waste acid is applied to the next batch of nitration reaction. Add 500 kg of water and 2 kg of caustic soda to the organic layer, stir for 1 hour and let it stand for stratification, then add 500 kg of water, and wash with water to obtain 2,4,6-trimethyl-m-dinitrobenzene.

[0024] Add the above-mentioned 2,4,6-trimethyl-m-dinitrobenzene to a 1000L liter autoclave, then add 10kg of Ni catalyst, 320kg of ethanol, and replace with nitrogen and hydrogen. Start stirring and heat up to 65°C, start hydrogenation, control hydrogenation pressure 2MP...

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Abstract

The invention relates to a synthesis method of 2,4,6-trimethyl-m-phenylenediamine. The method is characterized by comprising the steps of: (1) dropwise adding mixed acid into mesitylene for nitration and generation of 2,4,6-trimethyl-m-dinitrobenzene; after the reaction, standing for layering; neutralizing and washing an obtained organic layer to obtain 2,4,6-trimethyl-m-dinitrobenzene; (2) adding the 2,4,6-trimethyl-m-dinitrobenzene the obtained the step (1) to an autoclave, then adding a catalyst and a solvent, replacing the air in the autoclave with nitrogen gas, introducing hydrogen gas and conducting hydrogenation reduction to form 2,4,6-trimethyl-m-phenylenediamine, wherein the hydrogenation temperature is 50-120 DEG C, and the catalyst is a nickel catalyst; discharging hydrogen after the hydrogenation reduction, discharging the materials, removing methanol, cooling, crystallizing, and filtering to obtain the 2,4,6-trimethyl-m-phenylenediamine. The method has the advantages of short synthetic route, high product purity, high yield, few reaction steps, and long usage period of a hydrogenation reduction catalyst.

Description

technical field [0001] The invention relates to a method for synthesizing 2,4,6-trimethyl-m-phenylenediamine, which belongs to the technical field of organic synthesis. Background technique [0002] 2,4,6-Trimethyl-m-phenylenediamine is an intermediate of acidic and reactive dyes, medicine and photosensitive materials. Widely used in dye and pharmaceutical industries. [0003] In the prior art, the synthetic method of 2,4,6-trimethyl-m-phenylenediamine generally adopts mesitylene as a raw material, and first brominates to generate 2,4,6-trimethylbenzene bromide, Then nitrate with mixed acid to generate 2,4,6-trimethyl m-dinitrobenzene bromide, and finally debromine through hydrogenation reduction under the action of catalyst to generate 2,4,6-trimethyl m-phenylenediamine. There are following problems in adopting this synthetic route: (1) many reaction steps; (2) the hydrogenation reduction pressure is as high as 5-7.5 MPa; (3) the hydrogenation reduction catalyst is easily...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C209/36C07C211/47
CPCC07C209/36C07C201/08C07C211/47C07C205/06
Inventor 耿宏倪良袁剑杨钢
Owner JIANGSU TIANJIAYI CHEM CO LTD
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