Method for preparing 4,6-diaminoresorcinol dihydrochloride through one-pot synthesis

A technology of diaminoresorcinol hydrochloride and diacetylresorcinol is applied in the field of preparation of 4,6-diaminoresorcinol hydrochloride (DAR·2HCl), which can solve the problem of production efficiency It can improve the efficiency and yield, simplify the process flow, and promote the development of industrialization.

Active Publication Date: 2014-04-16
CHONGQING INST OF GREEN & INTELLIGENT TECH CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Aiming at the problems existing in the existing resorcinol acetylation and oximation methods, such as many process steps, low production efficiency, and high toxicity of raw materials, the present invention proposes to use 4,6-diacetyl resorcinol as a raw material to efficiently prepare 4 , the method of 6-diaminoresorcinol hydrochloride, because the process steps of this method are simple, and the reaction only needs to be carried out in one container or equipment, so the method is referred to as a one-pot method for short.

Method used

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  • Method for preparing 4,6-diaminoresorcinol dihydrochloride through one-pot synthesis
  • Method for preparing 4,6-diaminoresorcinol dihydrochloride through one-pot synthesis
  • Method for preparing 4,6-diaminoresorcinol dihydrochloride through one-pot synthesis

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Experimental program
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Effect test

Embodiment 1

[0019] DAR hydrochloride was prepared by one-pot method at 65℃ and the molar ratio of hydroxylamine hydrochloride / polyphosphoric acid / resorcinol was 2.2 / 3 / 1.

[0020] Weigh polyphosphoric acid (PPA, 15.80g) and 4,6-diacetylresorcinol (3.00g) in a 100mL three-neck flask, add hydroxylamine hydrochloride (2.15g) to it under stirring conditions, and raise the temperature to 65°C, take samples every half hour for HPLC, observe the reaction, after the reaction is complete, cool to room temperature, add hydrochloric acid (6mol / L, 20 mL) and SnCl 2 (0.05g), continue to stir and raise the temperature to 100°C, and react for 2 hours. After cooling in air, the crystals were precipitated, filtered with suction, washed with hydrochloric acid, washed with ethanol, and vacuum-dried in a glass drying oven. The conversion rate was 43.5%.

Embodiment 2

[0022] DAR hydrochloride was prepared by one-pot method under the condition of 80℃ and the molar ratio of hydroxylamine hydrochloride / polyphosphoric acid / resorcinol at 2.2 / 3 / 1.

[0023] Weigh polyphosphoric acid (PPA, 15.80g) and acetyl resorcinol (3.00g) into a 100mL three-necked flask. Under stirring conditions, add hydroxylamine hydrochloride (2.15g) to it, raise the temperature to 80°C, take samples for HPLC every half hour, observe the reaction, after the reaction is completed, cool to room temperature, add hydrochloric acid (6mol / L, 20 mL ) and SnCl 2 (0.05g), continue to stir and raise the temperature to 100°C, and react for 2 hours. After cooling in air, crystals were precipitated, filtered with suction, washed with hydrochloric acid, washed with ethanol, and vacuum-dried in a glass drying oven. The conversion rate was 75.5%.

Embodiment 3

[0025] DAR hydrochloride was prepared by one-pot method at 95°C and the molar ratio of hydroxylamine hydrochloride / polyphosphoric acid / resorcinol was 2.2 / 3 / 1.

[0026] Weigh polyphosphoric acid (PPA, 15.80g) and acetyl resorcinol (3.00g) into a 100mL three-necked flask. Under stirring conditions, add hydroxylamine hydrochloride (2.15g) to it, raise the temperature to 95°C, take samples for HPLC every half hour, observe the reaction, after the reaction is completed, cool to room temperature, add hydrochloric acid (6mol / L, 20 mL ) and SnCl 2(0.05g), continue to stir and raise the temperature to 100°C, and react for 2 hours. After cooling in air, crystals were precipitated, filtered with suction, washed with hydrochloric acid, washed with ethanol, and vacuum-dried in a glass drying oven. The conversion rate was 69.7%.

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Abstract

The invention discloses a method for preparing 4,6-diaminoresorcinol dihydrochloride through one-pot synthesis. The method mainly comprises the steps of: by taking Bronsted acid such as polyphosphoric acid, concentrated sulfuric acid or methanesulfonic acid as the catalyst and the solvent, realizing oximation, Beckmann rearrangement, hydrolysis and hydrocchlorination of 4,6-diacetylresorcinol, and thus obtaining the 4,6-diaminoresorcinol dihydrochloride (DAR.2HCl), wherein the mol ratio of hydroxylamine hydrochloride, the Bronsted acid catalyst and the 4,6-diacetylresorcinol is (2.0-2.5) / (1-10) / 1, and the reaction temperature ranges from 65 to 125 DEG C. The method provided by the invention is simple in process steps and efficient in preparation; therefore, the industrialization of the 4,6-diaminoresorcinol dihydrochloride is greatly promoted.

Description

technical field [0001] The present invention relates to the preparation of 4,6-diaminoresorcinol hydrochloride (DAR·2HCl), in particular to the preparation of 4,6-diaminoresorcinol salt using 4,6-diacetylresorcinol The method for acid salt belongs to the technical field of organic chemical synthesis. Background technique [0002] Poly-p-phenylene-benzobisoxazole fiber (Poly-p-phenylene-benzobisoxazole, referred to as PBO), known as the 21st century super fiber. It was first developed by the United States in the 1980s for the development of the aerospace industry. Later, the patent was transferred to Japan's Toyobo Corporation and industrialized. So far, Toyobo is still the only company in the world with this technology. The high temperature resistance of PBO fiber is the highest among organic materials; its tensile strength and modulus are much higher than those of carbon fibers, and it is the fiber material with the largest tensile strength and modulus so far; at the same...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C215/80C07C213/02
Inventor 陈凤贵徐愿坚高镱萌
Owner CHONGQING INST OF GREEN & INTELLIGENT TECH CHINESE ACADEMY OF SCI
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