Clean production method and device of dinitrotoluene

A dinitrotoluene and clean production technology, which is applied in the direction of nitro compound preparation, sustainable manufacturing/processing, chemical industry, etc., can solve the problems of large energy consumption, high recycling cost, and long time, so as to save resources, The effect of reducing reaction time and increasing yield

Inactive Publication Date: 2012-12-26
LIAONING QINGYANG SPECIAL CHEM
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to solve the problem that the recovery of nitric acid mixed acid in the prior art needs to consume a large amount of

Method used

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  • Clean production method and device of dinitrotoluene
  • Clean production method and device of dinitrotoluene

Examples

Experimental program
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Example Embodiment

[0039] Example 1

[0040] A clean production method of dinitrotoluene, the specific steps are as follows:

[0041] Step one, nitrification

[0042] Toluene and 90% nitric acid are used as raw materials, and the nitration reaction is carried out through the microreactor 1 under the condition that the feed ratio of toluene to nitric acid is 1:5. The structure diagram of the microreactor 1 is as follows: figure 2 As shown, the residence time of the materials in the microreactor 1 is controlled at 8s, the reaction temperature is 58°C, and DNT and HNO are obtained after nitration 3 And H 2 0 mixed solution;

[0043] Step two, separation

[0044] The crude mixed solution of dinitrotoluene and dilute nitric acid obtained in step 1 is separated from dinitrotoluene and dilute nitric acid by a fiber bed liquid liquid phase separator at 55°C to obtain dinitrotoluene products and dilute nitric acid. Nitric acid, the purity of the dinitrotoluene product was determined to be 94.6%, the yield was 9...

Example Embodiment

[0051] Example 2

[0052] A clean production method of dinitrotoluene, the specific steps are as follows:

[0053] Step one, nitrification

[0054] Toluene and nitric acid with a concentration of 93% are used as raw materials. Under the condition that the feed ratio of toluene to nitric acid is 1:6, the nitration reaction is carried out through the microreactor 1, and the residence time of the materials in the microreactor 1 is controlled at 10s. Temperature: 60℃, DNT and HNO are obtained after nitration 3 And H 2 0 mixed solution;

[0055] Step two, separation

[0056] The crude mixed solution of dinitrotoluene and dilute nitric acid obtained in step 1 is separated from dinitrotoluene and dilute nitric acid by a fiber bed liquid liquid phase separator at 57° C. to obtain dinitrotoluene products and dilute nitric acid. Nitric acid, the purity of the dinitrotoluene product was determined to be 95.6%, the yield was 93%, and the concentration of dilute nitric acid produced was 88.51%;

[...

Example Embodiment

[0059] Example 3

[0060] A clean production method of dinitrotoluene, the specific steps are as follows:

[0061] Step one, nitrification

[0062] Toluene and 95% nitric acid are used as raw materials. Under the condition that the feed ratio of toluene and nitric acid is 1:7, the nitration reaction is carried out through the microreactor 1. The residence time of the materials in the microreactor 1 is controlled at 12s. Temperature: 60℃, DNT and HN0 are obtained after nitration 3 And H 2 0 mixed solution;

[0063] Step two, separation

[0064] The crude mixed solution of dinitrotoluene and dilute nitric acid obtained in step 1 is separated from dinitrotoluene and dilute nitric acid by a fiber bed liquid liquid phase separator at 58°C to obtain dinitrotoluene products and dilute nitric acid. Nitric acid, the purity of the dinitrotoluene product was determined to be 91.2%, the yield was 91%, and the concentration of dilute nitric acid produced was 89.92%;

[0065] Step three, thicken or ...

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Abstract

The invention relates to a clean production method and a clean production device of dinitrotoluene, belonging to the field of chemical processes. The clean production method for preparing dinitrotoluene is realized through a methylbenzene micro-reactor nitration process, a fiber bed liquid-liquid separator separation process of nitric acid and dinitrotoluene mixture, and a dilute nitric acid thickening and concentration process. The clean production device of dinitrotoluene comprises a micro-reactor, a fiber bed separator, a mixing tank, a high-pressure kettle, a cooler, a bleaching tower, a concentrating tower, a condenser, a nitric acid storage tank, a delivery pump, a magnesium sulfate storage tank and an evaporator. Since nitration reaction is completed by using the micro-reactor, the micro-reactor consists of many micro-tubes which are connected in parallel, the specific surface area is very large and continuous production processes are formed, the heat exchange efficiency and the mixing efficiency are good, the reaction temperature can be accurately controlled, reaction materials can be accurately controlled to be instantly mixed according to accurate proportions, the yield, the selectivity and the safety are improved, and the reaction time is reduced.

Description

technical field [0001] The invention relates to a clean production method and device of dinitrotoluene, belonging to the field of chemical technology. Background technique [0002] Toluene diisocyanate, TDI for short, is mainly used in the production of polyurethane foam. Due to the excellent performance of polyurethane foam plastics and widely used, the market demand continues to increase, resulting in an increasing demand for dinitrotoluene (DNT), the main raw material for the manufacture of toluene diisocyanate (TDI). [0003] At present, the industrial production of DNT generally adopts the production process of nitrating toluene with nitric-sulfur mixed acid. A large amount of nitric-sulfur mixed acid needs to be concentrated during production. When the concentration of dilute sulfuric acid is too low (less than 40%), if it is recycled, the concentrated treatment process It needs to consume a lot of energy and the cost of recycling is high; if it is not recycled and di...

Claims

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Application Information

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IPC IPC(8): C07C205/06C07C201/08
CPCY02P20/10
Inventor 张洪林王东伟刘宝民吕文方缪成蛟全树新
Owner LIAONING QINGYANG SPECIAL CHEM
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