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2, 4-diaminotoluene purification method

A diaminotoluene and crystallizer technology, which is applied in the purification/separation of amino compounds, organic chemistry, etc., can solve the problems of secondary pollution, cannot meet the needs of industrial production, and the molecular sieve method has a small output, and achieves a small overall footprint , the effect of compact structure

Active Publication Date: 2015-11-18
CANGZHOU FENGYUAN ENVIRONMENTAL PROTECTION SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the output of the resin method and the molecular sieve method are small, which cannot meet the needs of industrial production, and the residual liquid of the derivatization crystallization method is difficult to handle, which is easy to cause secondary pollution

Method used

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  • 2, 4-diaminotoluene purification method
  • 2, 4-diaminotoluene purification method

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0063] Melt 500kg of 2,4 and 2,6-diaminotoluene mixture (isomerization ratio: 2,4:2,6=80:20) at a temperature of 90°C and pump it into a crystallizer that is also preheated at 90°C Medium; adjust the temperature of the circulating water in the thermostat sleeve, slowly reduce (cooling rate 2°C / h) the temperature of the crystallizer to 65°C, and keep the temperature at this temperature for half an hour, then release the raffinate; adjust the temperature in the thermostat sleeve The circulating water temperature rises slowly (heating rate 4°C / h), and then keeps the temperature for half an hour after reaching 86°C. The sweating liquid collected during the heating process is stored separately from the residual liquid; raise the temperature of the crystallizer to 100°C to melt all the internal materials After that, release the product. 250 kg of a mixture of 2,4-diaminotoluene and 2,6-diaminotoluene (isomerization ratio 95:5) was obtained.

Embodiment 2

[0065] Melt 250kg of the product in Example 1 at a temperature of 100°C, and pump it into a crystallizer at 95°C; adjust the temperature of the circulating water in the thermostat sleeve, and slowly reduce the temperature of the crystallizer (1.5°C / h) to 75°C, And keep the temperature at this temperature for half an hour, then release the residual liquid; adjust the temperature of the circulating water in the thermostat sleeve to increase slowly (2°C / h), and keep the temperature at 98°C for half an hour. Store the residual liquid separately; raise the temperature of the crystallizer to 100°C to melt all the internal materials, and release the product. 200 kg of 2,4-diaminotoluene was obtained, and the purity (GC method) of the product was 99.1%.

Embodiment 3

[0067] Mix 400kg of 2,4 and 2,6-diaminotoluene mixture (isomer ratio: 2,4:2,6=80:20) with 100kg of sweating liquid in Example 1, melt at a temperature of 90°C, Pump into the crystallizer at 90°C; adjust the temperature of the circulating water in the thermostat sleeve, slowly lower the temperature of the crystallizer (1.5°C / h) to 75°C, and keep the temperature at this temperature for half an hour to release the raffinate; Adjust the temperature of the circulating water in the thermostat sleeve to increase slowly (2°C / h), keep the temperature at 98°C for half an hour, store the sweating liquid collected during the temperature rise and the residual liquid separately; raise the temperature of the crystallizer to 100°C, so that After all the internal materials are melted, the product is released. 280 kg of a mixture of 2,4-diaminotoluene and 2,6-diaminotoluene (isomerization ratio 95:5) was obtained.

[0068] In a word, the present invention also has the following advantages at l...

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Abstract

The invention provides a 2, 4-diaminotoluene purification method. The method comprises the steps that an initial raw material composed of 2, 4-diaminotoluene and 2, 6-diaminotoluene is fed into a preheated crystallizer after being dissolved; the crystallizer is cooled at a preset cooling speed until crystals are dissolved out; heat is preserved until crystallizing layers grow up completely; residual liquor in the crystallizer is discharged, and temperature of the crystallizer is raised at a preset temperature raising speed for carrying out sweating processing on the crystallizing layers; sweat liquid is discharged from the crystallizer; the temperature of the crystallizer is raised so as to dissolve the crystallizing layers in the crystallizer completely, so that liquid 2, 4-diaminotoluene product is obtained. By meticulously designing all the technological steps, purification of 2, 4-diaminotoluene is practical for industrialization.

Description

technical field [0001] The invention relates to a technology for purifying 2,4-diaminotoluene from mixed diaminotoluene (TDA). Background technique [0002] 2,4-diaminotoluene is an important dye intermediate and an important raw material for the production of toluene diisocyanate (TDI). The method of industrially synthesizing TDA is usually to first nitrate toluene to obtain mixed dinitrotoluene, and then obtain meta-position mixed dinitrotoluene after rectification and separation to remove ortho-position dinitrotoluene, and then reduce to obtain mixed TDA, 2,4- The content of TDA and 2,6-TDA mainly has two ratios (mass isomerization ratio): about 80:20 or about 65:35. Because the quality of dyes synthesized by pure 2,4-TDA is better, and the performance of polyurethane polymerized with pure 2,4-TDA is better, so the economical and efficient purification of 2,4-TDA has a broad industry prospect. [0003] At present, although there are related reports on the preparation o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C209/86C07C211/50
Inventor 苏德水朱建华黄津于建才王长飞
Owner CANGZHOU FENGYUAN ENVIRONMENTAL PROTECTION SCI & TECH
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