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A kind of synthetic method of 2,6-dinitroterephthalic acid

A technology of dinitroterephthalic acid and synthetic methods, which is applied in the preparation of nitro compounds, chemical instruments and methods, and the preparation of organic compounds, and can solve the problems of hindering cyclization reactions and large impacts, and achieve easy-to-obtain raw materials , high industrial feasibility, simple post-processing effect

Active Publication Date: 2022-04-19
ZHEJIANG UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] At present, the AB type new monomer 4-(5-amino-6-hydroxyl-2-benzoxazolyl)-3,5-diaminobenzoic acid ( DAAB) can be prepared from 4,6-diaminoresorcinol hydrochloride (DAR 2HCl) and 2,6-diaminoterephthalic acid, after amino protection, monoesterification, condensation, and cyclization , but since the steric hindrance has a great influence on the reaction during the cyclization process, the protected amino group has a very large protecting group, which will seriously hinder the cyclization reaction.

Method used

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  • A kind of synthetic method of 2,6-dinitroterephthalic acid

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] In a 250mL four-neck flask equipped with a thermometer, put 18.96mL HNO 3 , inject 44.48mL of concentrated sulfuric acid in an ice-water bath with stirring. After the concentrated nitric acid and concentrated sulfuric acid are mixed evenly, 15mL of p-xylene is dropped into it with a constant pressure dropping funnel, and the dropping temperature is controlled at 20-30°C for 30 minutes, the solution is heated to 80°C and reacted for 30 minutes. After the reaction, cool to room temperature, pour the reaction solution into 250mL ice water to quench, filter, and recrystallize the filter cake twice in anhydrous methanol to obtain needle-like crystal powder, which is collected with 2,6-dinitro-p-xylene The yield was 54.67%, and the HPLC analysis mass fraction was 97.68%.

[0022] FT-IR (KBr, cm -1 ): 3078.5(s), 2932.9(s), 2869.6(s), 1532.3(s), 1351.4(s), 1289.2(s), 807.5(s).

[0023] 1 H-NMR (DMSO, δ, ppm): 8.39 (H, s, ArH), 8.39 (H, s, ArH), 2.34 (3H, s, -CH 3 ), 2.34 (...

Embodiment 2～6

[0031] Embodiment 2~6 adopts the same operating procedure of embodiment 1, gets different parameters to test according to the parameter range described in the present invention, it can be seen that the obtained 2,6-dinitro-p-xylene and 2,6-dinitro-p-xylene under these process conditions The purity of 6-dinitroterephthalic acid hydrochloride is above 83%, and the net yields of 2,6-dinitro-p-xylene and 2,6-dinitroterephthalic acid are both 31 %, more than 8%, can be applied to the industrial synthesis of 2,6-dinitro-p-xylene and 2,6-dinitro-terephthalic acid hydrochloride.

Embodiment 2

[0033] In a 250mL four-necked flask equipped with a thermometer, put 12.66mL of HNO 3 , inject 44.48mL of concentrated sulfuric acid in an ice-water bath with stirring. After the concentrated nitric acid and concentrated sulfuric acid are mixed evenly, 15mL of p-xylene is dropped into it with a constant pressure dropping funnel, and the dropping temperature is controlled at 20-30°C for 30 minutes, the solution is heated to 80°C and reacted for 30 minutes. After the reaction, cool to room temperature, pour the reaction solution into 250mL ice water to quench, filter, and recrystallize the filter cake twice in anhydrous methanol to obtain needle-like crystal powder, which is collected with 2,6-dinitro-p-xylene The yield was 46.67%, and the HPLC analysis mass fraction was 92.34%.

[0034] FT-IR (KBr, cm -1 ): 3078.5(s), 2932.9(s), 2869.6(s), 1532.3(s), 1351.4(s), 1289.2(s), 807.5(s).

[0035] 1 H-NMR (DMSO, δ, ppm): 8.39 (H, s, ArH), 8.39 (H, s, ArH), 2.34 (3H, s, -CH 3 ), 2...

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Abstract

A kind of synthetic method of 2,6-dinitroterephthalic acid, described method is: mix concentrated sulfuric acid and concentrated nitric acid uniformly, obtain mixed acid, drop p-xylene into mixed acid, control dropping temperature at 30 ℃ After dropping, the temperature is raised to 50-90°C for 20-60 minutes, and then the reaction solution is post-treated to obtain 2,6-dinitro-p-xylene; 2,6-dinitro-p-xylene and inorganic alkali are dissolved In a solvent, raise the temperature to 40-80°C, put potassium permanganate into the reaction system, raise the temperature to reflux reaction for 15-24 hours after the feeding, and then the reaction liquid is post-treated to obtain 2,6-dinitroterephthalic acid The invention has the advantages of easy control of reaction process parameters, easy acquisition of raw materials, short reaction time, simple post-treatment, high atom utilization rate, high purity, and high industrial feasibility.

Description

technical field [0001] The invention relates to a method for synthesizing 2,6-dinitroterephthalic acid, a novel monomer of diamino-modified PBO. Background technique [0002] Diamino-modified PBO, such as the new monomer 2,6-dinitroterephthalic acid (2,6-DNTA) shown in formula (1), is also widely used in dyes in addition to being a new monomer for modified PBO and pharmaceutical industries. [0003] [0004] At present, the AB type new monomer 4-(5-amino-6-hydroxyl-2-benzoxazolyl)-3,5-diaminobenzoic acid ( DAAB) can be prepared from 4,6-diaminoresorcinol hydrochloride (DAR 2HCl) and 2,6-diaminoterephthalic acid, after amino protection, monoesterification, condensation, and cyclization , but since the steric hindrance has a great influence on the reaction during the cyclization process, the protected amino group has a very large protecting group, which will seriously hinder the cyclization reaction. Therefore, in order to reduce the influence of steric hindrance effect,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C201/12C07C205/57
CPCC07C201/12C07C201/08C07C205/57C07C205/06
Inventor 赵德明俞超吴纯鑫张建庭金宁人
Owner ZHEJIANG UNIV OF TECH
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