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Preparation method for dinitrotoluene

A technology for dinitrotoluene and toluene, applied in the field of preparation of dinitrotoluene, can solve the problems of high cost and limit the industrial application of the Kyodai method, and achieve the effects of less three wastes, convenient recovery and good selectivity

Inactive Publication Date: 2009-09-16
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the industrial production of O 3 The method is mainly the high-voltage arc method, and the cost is high, which limits the industrial application of the Kyodai method
Currently, no 2 / O 2 Dinitration reaction of toluene in the system

Method used

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  • Preparation method for dinitrotoluene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Weigh 46g of toluene into the autoclave, and then add 0.46g of Hβ molecular sieve and 184g of liquid nitrogen dioxide respectively. After the cover is sealed, nitrogen is introduced, and the pressure is tested to confirm that the autoclave does not leak. Then the pressure was relieved and oxygen was introduced to keep the pressure of the reactor at 5MPa. Turn on the stirrer, 400 revolutions per minute, turn on the circulating cooling water, and keep the reaction temperature at 80°C basically unchanged. After stirring for 0.5h, close the oxygen inlet valve, slowly release the gas in the reactor, and ventilate with nitrogen. The exhaust gas is emptied after being absorbed by lye. Stop stirring, then transfer the reaction material to a 500mL glass beaker, filter, wash the filter residue with water, and recover the catalyst. After neutralizing the filtrate, pour it into an equal volume of ice water, and immediately a solid precipitates out. Let it stand overnight, filter, wash ...

Embodiment 2

[0022] 46g toluene, the catalyst is changed to HZSM-5, the mass of HZSM-5 is 6.9g, the liquid nitrogen dioxide is changed to 69g, the reaction pressure is changed to 0.1MPa, the reaction temperature is changed to 20°C, and the reaction time is changed to 10h. Other reactions and post-treatments are the same as in Example 1. The yield of dinitrotoluene was 90.1% (calculated as toluene), and the ratio of 2,4-dinitrotoluene and 2,6-dinitrotoluene was 33:1. After recrystallization, 79.3 g of 2,4-dinitrotoluene was obtained.

Embodiment 3

[0024] 46g toluene, the catalyst is changed to HY, the mass of HY is 4.6g, the liquid nitrogen dioxide is changed to 46.0g, the reaction pressure is changed to 0.5MPa, the reaction time is changed to 10h, and the amount of ice water is changed to 10 of the filtrate volume obtained from the filtration of the reactant. The other reactions and post-treatments are the same as in Example 1. The yield of dinitrotoluene was 90.3% (calculated as toluene), and the ratio of 2,4-dinitrotoluene and 2,6-dinitrotoluene was 33:1. After recrystallization, 79.5 g of 2,4-dinitrotoluene was obtained.

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Abstract

The invention discloses a preparation method for dinitrotoluene, which comprises the following steps: taking toluene as a raw material, under the action of a catalyst, taking NO2 as a nitrating agent, and introducing O2 into a reaction kettle; simultaneously controlling the pressure in the reaction kettle to between 0.1 and 5.0 MPa, the reaction temperature between 15 DEG C below zero and 80 DEG C, and a reaction for 0.5 to 24 hours; after the reaction, cooling to room temperature, relieving the pressure, and filtering reaction products; and recovering a filter cake A which is the catalyst, cooling the filter liquor by ice water, precipitating solid, filtering the filter liquor again, obtaining a filter cake B, and washing and drying the filter cake B to obtain the dinitrotoluene, wherein the catalyst is one or mixture of more than two of Bronsted acids and Lewis acids in any proportion. The preparation method has high toluene conversion rate, good catalyst selectivity, convenient catalyst recovery, direct mechanical application of the recovered catalyst without processing the catalyst, simple operation, high resource utilization rate and less three wastes.

Description

(1) Technical field [0001] The invention relates to a preparation method of dinitrotoluene, in particular to a 2 / O 2 A method for preparing dinitrotoluene by dinitrating toluene in the system. (2) Background technology [0002] Dinitrotoluene (DNT) is an important organic intermediate, mainly including 2,4-Dinitrotoluene (2,4-DNT) and 2,6-Dinitrotoluene (2,6-DNT). This isomer is an important organic chemical raw material, widely used in the synthesis of dye intermediates, explosives and propellants. It can be prepared directly from p-nitrotoluene and reacted with nitric acid under the action of sulfuric acid (mixed acid method); it can also be prepared from toluene as a raw material by nitration to synthesize mixed dinitrotoluene, then crystallized and separated [China Petroleum And Chemical Standards and Quality, 2003, 10: 25-26], in this way, nitric acid is directly used for the nitration reaction, and the nitric acid needs to be greatly excessive. Coon et al. studied the nitr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C205/06C07C201/08
CPCY02P20/584
Inventor 史鸿鑫高立定
Owner ZHEJIANG UNIV OF TECH
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