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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  • Summary
  • 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 energy, the recovery cost is high, and if it is not recovered, it will cause serious environmental pollution; Clean production method and device of dinitrotoluene

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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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Effect test

Embodiment 1

[0040] A kind of dinitrotoluene clean production method, concrete steps are as follows:

[0041] Step one, nitrification

[0042] With toluene and the nitric acid that concentration is 90% as raw material, under the condition that toluene and nitric acid feeding ratio are 1: 5, carry out nitration reaction by microreactor 1, microreactor 1 structure schematic diagram is as figure 2 As shown, the residence time of the material 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 2. Separation

[0044] The crude mixed solution of dinitrotoluene and dilute nitric acid obtained in step 1 is separated from dinitrotoluene and dilute nitric acid through a fiber bed liquid-liquid phase separator at 55° C. to obtain dinitrotoluene products and dilute nitric acid Nitric acid, the measured dinitrotoluene product purity is 94.6%, the yield is 92%, and the concentration of dilu...

Embodiment 2

[0052] A kind of dinitrotoluene clean production method, concrete steps are as follows:

[0053] Step one, nitrification

[0054] Toluene and concentration are the nitric acid of 93% as raw material, under the condition that toluene and nitric acid feed ratio are 1: 6, carry out nitration reaction by microreactor 1, the residence time of material in microreactor 1 is controlled at 10s, reaction Temperature: 60°C, DNT and HNO are obtained after nitration 3 and H 2 0 mixed solution;

[0055] Step 2. Separation

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

[0057] Step 3. Concentrate or Concentrate

[0058] Con...

Embodiment 3

[0060] A kind of dinitrotoluene clean production method, concrete steps are as follows:

[0061] Step one, nitrification

[0062] With toluene and the nitric acid that concentration is 95% as raw material, under the condition that toluene and nitric acid feed ratio are 1: 7, carry out nitration reaction by microreactor 1, the residence time of material in microreactor 1 is controlled at 12s, reaction Temperature: 60°C, DNT and HN0 are obtained after nitration 3 and H 2 0 mixed solution;

[0063] Step 2. Separation

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

[0065] Step 3. Concentrate or Concentrate

[006...

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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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