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Preparation method of 2,4-dimethoxyaniline

A technology of dimethoxyaniline and dimethoxynitrobenzene, which is applied in the field of preparation of 2,4-dimethoxyaniline, can solve problems such as excessive three wastes, serious equipment corrosion, and environmental pollution

Inactive Publication Date: 2018-05-15
YANTAI ANOKY FINE CHEM CO LTD +4
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is that the existing 2,4-dimethoxyaniline preparation method has harsh reaction conditions, severe equipment corrosion, many wastes, serious environmental pollution or low catalyst recycling rate, cannot be continuously produced, and the product Purity or production capacity are low defects, and a kind of preparation method of 2,4-dimethoxyaniline is provided

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  • Preparation method of 2,4-dimethoxyaniline

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Embodiment 1

[0095] A kind of preparation method of 2,4-dimethoxyaniline, take 2,4-dimethoxynitrobenzene as raw material, adopt Pd / Al 2 o 3 The catalyst is used for continuous catalytic hydrogenation reaction in the reactor. After the catalyst is separated and recovered, the reducing solution is desolvated and purified to obtain the target product 2,4-dimethoxyaniline.

[0096] Specific steps include:

[0097] (1) Put 5000kg of methanol and 1250kg of 2,4-dimethoxynitrobenzene into the chemical material tank, follow-up feeding is carried out according to the ratio, stir evenly, pump them into the first-stage hydrogenation reactor, add Pd / Al 2 o 3 Catalyst 125kg, the particle size of the catalyst is 10nm, pass through the nitrogen replacement system three times, then pass through the hydrogen replacement system three times, start stirring, raise the temperature to 90-100°C, and pump it into the first-stage hydrogenation tank at a flow rate of 6000L / h The raw material solution of 2,4-dim...

Embodiment 2

[0101] (1) Put 5000kg of methanol and 1250kg of 2,4-dimethoxynitrobenzene into the chemical feed tank, and follow up the ratio of feeding, stir evenly, pump them into the first-stage hydrogenation reactor, and add Pd / Al 2 o 3 125kg of catalyst, the particle size of the catalyst is 500μm; pass through the nitrogen replacement system three times, then pass through the hydrogen replacement system three times, start stirring, raise the temperature to 80-90°C, and pump it into the first-stage hydrogenation tank at a flow rate of 5000L / h The raw material solution of 2,4-dimethoxynitrobenzene is passed into H 2 , control the hydrogen pressure in the system to 3.0MPa, and add Pd / Al to the primary hydrogenation reactor every 3h 2 o 3 Catalyst 2.5kg, after the material in the primary hydrogenation kettle gradually increases, it flows into the secondary hydrogenation kettle through the overflow port, the material stays in the hydrogenation kettle for about 2-3h, and the reaction is qua...

Embodiment 3

[0105] (1) 12500kg of methanol and 1250kg of 2,4-dimethoxynitrobenzene are put into the chemical feed tank, and the subsequent feeding is stirred evenly according to the ratio. Al 2 o 3 Catalyst 125kg, the particle size of the catalyst is 10nm; pass through the nitrogen replacement system three times, then pass through the hydrogen replacement system three times, start stirring, raise the temperature to 90-100°C, and pump it into the first-stage hydrogenation tank at a flow rate of 6000L / h The raw material solution of 2,4-dimethoxynitrobenzene is passed into H 2 , control the hydrogen pressure in the system to 3.0MPa, and add Pd / Al to the primary hydrogenation reactor every 3h 2 o 3 Catalyst 2.5kg, after the material in the primary hydrogenation kettle gradually increases, it flows into the secondary hydrogenation kettle through the overflow port, the material stays in the hydrogenation kettle for about 2-3h, and the reaction is qualified (with 2,4-di Methoxynitrobenzene r...

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Abstract

The invention discloses a preparation method of 2,4-dimethoxyaniline. The preparation method comprises the following steps: performing continuous catalytic hydrogenation on 2,4-dimethoxynitrobenzene and then performing sedimentation and membrane filtration to obtain the 2,4-dimethoxyaniline. The preparation method disclosed by the invention is simple to operate, high in safety and capable of continuous production and can achieve the effects of high production efficiency, high product quality, low labor intensity, and high catalyst utilization rate, facilitates industrialization, and is environmentally friendly.

Description

technical field [0001] The invention relates to a preparation method of 2,4-dimethoxyaniline. Background technique [0002] 2,4-Dimethoxyaniline is an important fine chemical intermediate, mainly used in pharmaceutical and dye industries. At present, the methods for producing 2,4-dimethoxyaniline include iron powder reduction method or hydrazine hydrate reduction method of 2,4-dimethoxynitrobenzene. Among them, iron powder reduction causes serious pollution to the environment; while the reaction time of hydrazine hydrate reduction needs to be strictly controlled, otherwise side reactions will increase. [0003] Therefore, how to provide a method for preparing 2,4-dimethoxyaniline with high production efficiency, high product quality, low labor intensity and environmental friendliness is an urgent technical problem to be solved by those skilled in the art. Contents of the invention [0004] The technical problem to be solved by the present invention is that the existing 2...

Claims

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Application Information

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IPC IPC(8): C07C213/02C07C213/10C07C217/84
CPCY02P20/584C07C213/02C07C213/10C07C217/84
Inventor 刘祥庆刘云龙曲美君张永明戴杰
Owner YANTAI ANOKY FINE CHEM CO LTD
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