Method for synthetizing 3,5-dichloroaniline

A technology of dichloroaniline and pentachloronitrobenzene, applied in chemical instruments and methods, preparation of organic compounds, preparation of amino compounds, etc., can solve the problems of environmental pollution, high cost, low content, etc., and achieve energy saving and consumption reduction environment Pollution, the effect of addressing the source

Inactive Publication Date: 2014-01-15
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to overcome the problems of serious environmental pollution, high cost and low content in the existing 3,5-dichloroaniline production, the present invention provides a new synthesis method of 3,5-dichloroaniline, which not only has mild reaction conditions , and has the characteristics of low production cost, high content and light pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] a) Chlorination reaction operation steps:

[0021] Put 157.5 grams (1 mole) of meta-nitrochlorobenzene oil, 2.4 grams of catalyst and 400 grams of solvent in a 500 ml four-necked bottle, seal the equipment, heat and stir, and start to pass chlorine gas at 60~80 °C for 3 hours After the end, the temperature was lowered to crystallize, filtered, and washed until the Congo red test paper did not change color, and the pentachloronitrobenzene mixture was obtained.

[0022] b) Reductive dechlorination reaction steps:

[0023] Then the pentachloronitrobenzene mixture is placed in a 1000 ml autoclave, 0.5 g of platinum catalyst and 400 g of solvent are added, after the autoclave is closed and the airtightness is checked, nitrogen gas is fed to a pressure of 2 MPa, and then released, so Replaced 3 times to remove the air in the autoclave, introduced hydrogen to 3MPa, then vented, then introduced hydrogen to a pressure of 4MPa, heated to 100°C, reacted for 4 hours, cooled to roo...

Embodiment 2

[0025] a) chlorination reaction operation steps:

[0026] Put 157.5 grams (1 mole) of meta-nitrochlorobenzene oil, 2.4 grams of catalyst and 400 grams of solvent in a 500 ml four-necked bottle, seal the equipment, heat and stir, and start to pass chlorine gas at 60~80 °C for 3 hours After the end, cool down and crystallize, filter, wash until the Congo red test paper does not change color, and obtain a mixture of pentachloronitrobenzene, and then add 200ml of solvent to refine it to obtain a finished product of pentachloronitrobenzene with a purity of more than 99%.

[0027] b) Reductive dechlorination reaction operation steps:

[0028] Then the pentachloronitrobenzene finished product is placed in a 1000 milliliter autoclave, add 0.5 gram of platinum catalyst and 400 gram of solvent, after closing the autoclave and checking the airtightness, feed nitrogen to a pressure of 2MPa, then let it go, so Replaced 3 times to remove the air in the autoclave, introduced hydrogen to 3MP...

Embodiment 3

[0031] a) chlorination reaction operation steps:

[0032] Put 157.5 grams (1 mole) of nitrochlorobenzene meta-position oil, 2.4 grams and 300 grams of mantle solvent and 100 grams of fresh solvent in a 500 ml four-neck bottle, seal the equipment, heat and stir, and start to pass at 60-80 ° C Chlorine gas, the reaction was completed after 3 hours, cooled to crystallize, filtered, washed until the Congo red test paper did not change color, and the pentachloronitrobenzene mixture was obtained.

[0033] b) Reductive dechlorination reaction operation steps:

[0034] Then the pentachloronitrobenzene mixture is placed in a 1000 ml autoclave, 0.5 g of platinum catalyst and 400 g of solvent are added, after the autoclave is closed and the airtightness is checked, nitrogen gas is fed to a pressure of 2 MPa, and then released, so Replaced 3 times to remove the air in the autoclave, introduced hydrogen to 3MPa, then vented, then introduced hydrogen to a pressure of 4MPa, heated to 100°C,...

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Abstract

The invention discloses a method for synthetizing 3,5-dichloroaniline by using industrial production residues, namely meta-position oil, of p-nitrchlorobenzene and ortho-nitrochlorobenzene by two steps of chlorination and reductive dechlorination. The method adopts the following technical scheme: adding an organic solvent to nitrochlorobenzene meta-position oil as a raw material, directly producing a quintozene mixture by one-step chlorination under the effect of a catalyst, reacting for 0.5-10 hours under the condition of 10-180 DEG C, and then cooling to 30 DEG C; filtering out quintozene, and putting into an autoclave after washing into a neutral state by hot water; carrying out dechlorination reduction reaction under the effects of an organic solvent and the catalyst, wherein the reaction temperature is 60-200 DEG C, the reaction pressure is 1-20 MPa, and the reaction time is 1-20 hours; cooling to room temperature after the reaction is ended; leading in oxygen or air to stir after blowing off; filtering and distilling under reduced pressure to remove the solvent, so as to obtain the product 3,5-dichloroaniline, wherein the yield is 80-90%. Waste materials are changed into precious materials by a synthetic route adopted by the technology disclosed by the invention; the target of zero emission is achieved; the method has the advantages of sustainable development, energy conservation and consumption reduction, and small environmental pollution.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a method for synthesizing 3,5-dichloroaniline by using industrial production residues of p- and o-nitrochlorobenzene. Background technique [0002] 3,5-Dichloroaniline, as an important raw material for organic synthesis intermediates, is widely used in medicine, pesticides, dyes and other fields. At present, there are four main methods for the synthesis of 3,5-dichloroaniline, the chlorination and ammonification of p-(o)nitroaniline, the bromination and amination of dichlorobenzene, and the decarbonylation of 3,5-dichlorobenzamide , Polychlorinated nitrobenzene catalytic hydrodechlorination method. The traditional production process of 3,5-dichloroaniline in my country uses nitroaniline as the starting material, which is chlorinated to obtain 2,6-dichloro-4-nitroaniline, followed by diazotization reaction, and then sulfuric acid Copper reflux water decomposes the diazo group to...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/52C07C209/36C07C209/74
Inventor 张萍贺桂莲
Owner CHINA PETROLEUM & CHEM CORP
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