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Preparation method of p-phenylenediamine

A technology of p-phenylenediamine and terephthalamide, which is applied in the field of preparation of p-phenylenediamine, can solve the problems of serious environmental pollution, low product quality, high raw material cost, etc., achieve high product quality, reduce raw material consumption, increase yield effect

Active Publication Date: 2013-03-27
江苏万盛大伟化学有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] p-Phenylenediamine is an important chemical raw material, which is widely used in industries such as dyes, washing chemicals, rubber, and national defense. Before the demand, domestic manufacturers all use p-nitroaniline reduction to produce p-phenylenediamine, which has high raw material costs, Disadvantages such as serious environmental pollution and low product quality

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] 1) Ammonolysis

[0017] Crush 100g of discarded polyester beverage bottles into fragments with a diameter of 1-5cm, dry them and put them into an autoclave, then add 420mL of ethylene glycol and 62g of liquid ammonia, at a temperature of 160-180°C and a pressure of 8.5-9.5MPa Under the conditions, stir the reaction for 5 hours, then stop stirring, naturally cool down to 20~25°C, filter to obtain crystals, wash the filter cake twice with 150mL of water, and wash once with 60mL of methanol to obtain 81.6g of white crystal terephthalamide , the yield is 92%;

[0018] 2) Chlorination

[0019] Add 81.6g of terephthalamide obtained in step 1) into the reaction kettle, then add 1500mL of water, adjust the system temperature to 15~20°C, keep this temperature and feed chlorine gas for 4~5h, and HPLC detects that terephthalamide is completely consumed , stop the chlorine flow, filter and wash the filter cake with water (100mL×3 times) to obtain 107.8g of chloride with a purity ...

Embodiment 2

[0023] 1) Ammonolysis

[0024] Crush 100g of discarded polyester beverage bottles into pieces with a diameter of 1-5cm, dry them, put them into an autoclave, add 450mL of ethylene glycol and 70g of liquid ammonia, and heat them at a temperature of 160-180°C and a pressure of 8.5-9.5MPa Under the conditions, stir the reaction for 5 hours, then stop stirring, naturally cool down to 20~25°C, filter to obtain crystals, wash the filter cake twice with 160mL of water, and wash once with 60mL of methanol to obtain 82.5g of white crystal terephthalamide , the yield is 93%;

[0025] 2) Chlorination

[0026] Add 78.5g of terephthalamide into the reaction kettle, then add 1500mL of water, adjust the system temperature to 15~20°C, keep this temperature and feed chlorine gas for 4~5h, HPLC detects that terephthalamide is completely consumed, stop the chlorine flow , filtered and washed with water (3×100mL) to obtain 104g of chloride with a purity of 99.4% and a yield of 91.3%;

[0027] ...

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PUM

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Abstract

The invention discloses a preparation method of p-phenylenediamine, which comprises the following steps of: 1) ammonolysis: crushing waste polyester drink bottles, and mixing the crushed polyester drink bottle with ethylene glycol and liquid ammonia and stirring for reaction to obtain terephthalamide; 2) chlorination: reacting terephthalamide to react with chlorine to obtain a chloride; and 3) hofmann degradation: heating the water solution of chloride product NaOH or KOH, and carrying out the hofmann degradation to obtain p-phenylenediamine. In the ammonolysis and chlorination, mother liquor is applied, so that the yield is increased, and the consumption of raw material is reduced. In the degradation process, brown waste water contains more p-phenylenediamine. The p-phenylenediamine is extracted from the waste water by a solvent, so that the yield is increased, and the pollution control cost is reduced. The p-phenylenediamine is prepared in a way of waste ester regeneration, so that the problem of waste treatment in a environment-friendly manner is solved; furthermore, the content of isomer in the polyester is very low, so that the produced p-phenylenediamine contains little isomer, and the product is high in quality.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a preparation method of p-phenylenediamine. Background technique [0002] p-Phenylenediamine is an important chemical raw material, which is widely used in industries such as dyes, washing chemicals, rubber, and national defense. Before the demand, domestic manufacturers all use p-nitroaniline reduction to produce p-phenylenediamine, which has high raw material costs, Serious environmental pollution, low product quality and other shortcomings. However, polyester film or beverage bottles discarded in people's daily life are used as raw materials to synthesize p-phenylenediamine, which has good quality and low cost, overcomes the shortcomings of traditional processes, and opens up new possibilities for the recycling of waste and the synthesis of p-phenylenediamine. way. Contents of the invention [0003] The technical problem to be solved by the present invention is...

Claims

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Application Information

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IPC IPC(8): C07C211/51C07C209/58
Inventor 龚卫良黄德周
Owner 江苏万盛大伟化学有限公司
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