Solvent-free catalytic hydrogenation method for preparation of 2,4-dichloro-5-isopropoxy aniline

A technology of propoxyaniline and catalytic hydrogenation, which is applied in the preparation of amino compounds, the preparation of organic compounds, catalytic reactions, etc., can solve problems such as product purity decline and equipment corrosion, and achieve high product quality, low cost and high yield. Effect

Inactive Publication Date: 2016-10-12
济南和润化工科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the hydrogenation and dechlorination process of 2,4-dichloro-5-isopropoxyaniline catalytic hydrogenation process has the problem of hydrogenolysis and dechlorination, resulting in equipment corrosion and a decrease in product purity. Choosing a suitable additive can effectively reduce dechlorination and improve The content of the main product is also the research focus and difficulty of domestic and foreign researchers in this field

Method used

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  • Solvent-free catalytic hydrogenation method for preparation of 2,4-dichloro-5-isopropoxy aniline

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Add 1.2t of 2,4-dichloro-5-isopropoxynitrobenzene and 6kg of noble metal catalyst (self-made) into a 2m³ hydrogenation kettle, open the hydrogen valve, feed hydrogen into the hydrogenation kettle, stir and heat up the reaction , the reaction temperature is controlled at 80-100°C, the reaction pressure is controlled at 0.3-2.5MPA, the reaction speed is set at 700 rpm, and the hydrogen gas valve is closed until the hydrogen is not absorbed. The gas chromatographic analysis shows that the purity is 97.22%, the dechlorination amount is 1.9%, and the pH value of the oil phase is between 4-5.

Embodiment 2

[0017] Add 1.2t of 2,4-dichloro-5-isopropoxynitrobenzene, 6kg of noble metal catalyst (self-made), and 3kg of ethanolamine into a 2m³ hydrogenation kettle, open the hydrogen valve, and feed hydrogen into the hydrogenation kettle. Stir and heat up the reaction, the reaction temperature is controlled at 80-100°C, the reaction pressure is controlled at 0.3-2.5MPA, the reaction speed is set at 700 rpm, and the reaction is performed until no hydrogen is absorbed, the hydrogen valve is closed, the material is directly pressed, and the upper aqueous phase is separated. The purity of the crude product in the lower layer is 98.87% by gas chromatography, the dechlorination amount is 0.7%, and the pH value of the oil phase is between 5-6.

Embodiment 3

[0019] Add 1.2t of 2,4-dichloro-5-isopropoxynitrobenzene, 6kg of noble metal catalyst (self-made), and 2L of pyridine into a 2m³ hydrogenation kettle, open the hydrogen valve, and feed hydrogen into the hydrogenation kettle. Stir and heat up the reaction, the reaction temperature is controlled at 80-100°C, the reaction pressure is controlled at 0.3-2.5MPA, the reaction speed is set at 700 rpm, and the reaction is performed until no hydrogen is absorbed, the hydrogen valve is closed, the material is directly pressed, and the upper aqueous phase is separated. The purity of the crude product in the lower layer was analyzed by gas chromatography to be 98.72%, the dechlorination amount was 0.9%, and the pH value of the oil phase was between 5-6.

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Abstract

The invention especially discloses a solvent-free method for hydrogenation preparation of 2,4-dichloro-5-isopropoxy aniline from 2,4-dichloro-5-isopropoxy nitrobenzene, belonging to the field of catalytic hydrogenation production. The method uses 2,4-dichloro-5-isopropoxy nitrobenzene as a raw material and is characterized in that 2,4-dichloro-5-isopropoxy nitrobenzene reacts with hydrogen at a temperature of 80 to 100 DEG C and a pressure of 0.3 to 2.5 MPa in the presence of a catalyst and an auxiliary agent, no solvent is added, and water is separated after completion of the reaction so as to obtain chloroaniline. The catalyst is a noble metal catalyst prepared through independent research and development, and the usage amount of the catalyst is 0.05 to 20% of the mass of 2,4-dichloro-5-isopropoxy nitrobenzene; the auxiliary agent is a mixture of ethanolamine and pyridine, and the usage amount of the auxiliary agent is 0.01 to 10% of the mass of 2,4-dichloro-5-isopropoxy nitrobenzene; and chromatographic purity of obtained 2,4-dichloro-5-isopropoxy aniline is 99.5% or above, a dechlorination amount can be controlled within 0.1%, a conversion rate is 100%, and yield is 95% or above.

Description

technical field [0001] The invention belongs to the field of catalytic hydrogenation production, and particularly discloses a solvent-free method for preparing 2,4-dichloro-5-isopropoxynitrobenzene by hydrogenating 2,4-dichloro-5-isopropoxyaniline production method. Background technique [0002] 2,4-Dichloro-5-isopropoxyaniline is a key intermediate in the synthesis of high-efficiency herbicides such as "Oxadiazone" and "Daostar" etc. "Oxadiazone" herbicide has achieved industrial production , 2,4-dichloro-5-isopropoxyaniline is obtained by reduction of 2,4-dichloro-5-isopropoxynitrobenzene. The reduction methods include: metal powder method, such as reducing iron powder and zinc powder; stannous chloride method and traditional processes such as catalytic hydrogenation reduction method. Iron powder reduction, although low in equipment requirements, is difficult to deal with the three wastes, and the reduction yield is low. It has been listed in the "Industrial Structure Ad...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C209/36C07C217/84B01J23/38B01J31/02
CPCC07C209/36B01J23/38B01J31/0244B01J2231/641C07C217/84
Inventor 侯卫波唐国武王光韩龙凯王超李娟卢波司立鹏赵恩锋
Owner 济南和润化工科技有限公司
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