Method for preparing aminotoluene by catalytic hydrogenation of 2,4-dinitrotoluene or/and 2,6-dinitrotoluene

A technology of dinitrotoluene and aminotoluene, applied in the field of diaminotoluene, can solve the problems of large amount of reaction by-products, cannot be stored, and inconvenient to use, and achieves the effect of simplifying the production process and having obvious cost advantages.

Inactive Publication Date: 2009-07-08
甘肃中科药源生物工程股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] 1) Very inconvenient to use
Because the active component of the Raney nickel catalyst for catalytic hydrogenation is skeleton nickel, but skeleton nickel is extremely easy to catch fire in the air and cannot be preserved. It can only be used as a commodity in the form of nickel-aluminum alloy powder. Dissolve the aluminum, wash it and add it to the reaction system under the condition of isolating the air; in addition, the catalytic activity of Raney nickel often changes greatly due to different treatment conditions (such as alkali dissolution and washing conditions)
[0004]2) When Raney nickel catalyst is used, the amount of by-products of the reaction is large and the product yield is low
The hydrogenation of the Raney nickel catalyst to transform the nitro group into an amino group often requires a higher temperature, generally higher than 100 °C, and the pr

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Example 1: Preparation of 2,4-diaminotoluene by catalytic hydrogenation of 2,4-dinitrotoluene

[0019] First add 100 grams of 2,4-dinitrotoluene in the reaction kettle, then add 20% of the mass of 2,4-dinitrotoluene and be 95% ethanol, then add 2,4-dinitrotoluene Loaded catalyst with a mass of 3 to 6%, seal the reactor, completely replace the air in the reactor with hydrogen, then keep the inside of the reactor at normal pressure (about 0.1MPa), and start heating and stirring, after the temperature reaches 60°C, the inside of the reactor Introduce hydrogen to keep the pressure in the kettle at 1.0-3.0MPa (the test shows that the optimum pressure should be about 1.5MPa), start the hydrogenation reaction, and keep the temperature in the kettle at 60-90°C during the hydrogenation process. After about 3 to 8 hours of hydrogenation, the conversion rate reaches 95-99%, and then the reaction mixture and the catalyst are separated, and the separated catalyst is returned to the ...

Embodiment 2

[0021] Example 2: Preparation of 2,6-diaminotoluene by catalytic hydrogenation of 2,6-dinitrotoluene

[0022] First add 100 grams of 2,6-dinitrotoluene in the reaction kettle, then add 20% of the mass of 2,6-dinitrotoluene and be 95% ethanol, then add 2,6-dinitrotoluene Loaded catalyst with a mass of 3 to 6%, seal the reactor, completely replace the air in the reactor with hydrogen, then keep the inside of the reactor at normal pressure (about 0.1MPa), and start heating and stirring, after the temperature reaches 60°C, the inside of the reactor Introduce hydrogen to keep the pressure in the kettle at 1.0-3.0MPa (the test shows that the optimum pressure should be about 1.5MPa), start the hydrogenation reaction, and keep the temperature in the kettle at 60-90°C during the hydrogenation process. After about 3 to 8 hours of hydrogenation, the conversion rate reaches 95-99%, and then the reaction mixture and the catalyst are separated, and the separated catalyst is returned to the ...

Embodiment 3

[0024] Example 3: Catalytic hydrogenation of mixtures of 2,4-dinitrotoluene and 2,6-dinitrotoluene to prepare corresponding diaminotoluene

[0025]Add 100 grams of 2,4-dinitrotoluene and a mixture of 2,6-dinitrotoluene in the reactor according to the required ratio, wherein 2,4-dinitrotoluene and 2,6-dinitrotoluene The ratio is 4: 1 (mass ratio), then adding 20% ​​of the nitrotoluene mixture quality concentration is 95% ethanol, then adding the supported catalyst of 3 ~ 6% dinitrotoluene mixture quality, airtight reactor, Completely replace the air in the reactor with hydrogen, then keep the inside of the reactor at normal pressure (about 0.1MPa), and start heating and stirring. After the temperature reaches 60°C, put hydrogen into the reactor to keep the pressure inside the reactor at 1.0-3.0MPa (Tests show that the optimum pressure should be around 1.5MPa), start the hydrogenation reaction, keep the temperature in the kettle at 60-90°C during the hydrogenation process, and t...

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Abstract

The invention discloses a method for preparing corresponding diaminotoluene through catalytic hydrogenation of 2,4-dinitrotoluene or 2,6-dinitrotoluene or a mixture of the 2,4-dinitrotoluene and the 2,6-dinitrotoluene. The method for preparing the diaminotoluene through catalytic hydrogenation of the 2,4-dinitrotoluene comprises: respectively adding the 2,4-dinitrotoluene or the 2,6-dinitrotoluene or the mixture of the 2,4-dinitrotoluene and the 2,6-dinitrotoluene, and ethanol and a supported catalyst into a reaction kettle first; performing hydrogenation reaction for 3 to 8 hours at a temperature of between 60 and 90 DEG C, wherein the pressure of the hydrogenation reaction is between 1.5 and 3.0 MPa; and performing solid-liquid separation after the reaction is over, using separated supernatant for product separation, and conveying a separated solid catalyst back to a reaction system for continuous use.

Description

technical field [0001] The present invention relates to 2,4-dinitrotoluene or 2,6-dinitrotoluene or the mixture catalytic hydrogenation of 2,4-dinitrotoluene and 2,6-dinitrotoluene to prepare corresponding diaminotoluene method. Background technique [0002] The reduction of nitro compounds to amino compounds was first prepared by the method of iron powder and hydrochloric acid. This method is seriously polluting, and it is a process route that will be abolished in the near future as stipulated by the state. In recent years, most of this kind of production uses Raney nickel catalysts. , that is, the conversion of nitro to amino groups is realized by catalytic hydrogenation using Raney nickel as a catalyst, but the use of Raney nickel catalysts for catalytic hydrogenation has the following disadvantages: [0003] 1) It is extremely inconvenient to use. Because the active component of the Raney nickel catalyst for catalytic hydrogenation is skeleton nickel, but skeleton nick...

Claims

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Application Information

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IPC IPC(8): C07C209/36C07C211/43
Inventor 马建泰常青
Owner 甘肃中科药源生物工程股份有限公司
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