Preparation method of 4,5-dibromophthalic acid

A technology of bromophthalic acid and phthalic hydrazide, which is applied in the field of preparation of 4,5-dibromophthalic acid, can solve the problems of being unable to meet the batch demand of materials, unfavorable for environmental protection, and outdated methods. Achieve the effect of few steps, easy operation and low cost

Inactive Publication Date: 2016-06-08
ZHENGZHOU UNIVERSITY OF LIGHT INDUSTRY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Phthalic acid compounds are excellent metal ligands and valuable organic intermediates, and are important raw materials for the synthesis of phthalocyanine compounds. Phthalocyanine has a large π Conjugated aromatic systems have a wide range of applications in the fields of sensors, cancer fluorescence therapy, dyes, optical recording, electrochromic smart materials and solar photovoltaic devices, especially dibromophthalic acid is the synthesis of bromophthalocyanine compounds It is an urgently needed raw material, but 4,5-dibromophthalic acid is basically not sold in bulk on the market, and most of the reported synthesis methods are early literature (Chem.Ber., 1884, 17: 2494-2496; J.Chem .Soc.,1952,4615-4618; J.Amer.Chem.Soc.,1942,64:2639-2641), nitric acid is often used to oxidize at a high temperature of 170°C, the method is backward, and it is not conducive to environmental protection
Secondly, phthalic anhydride is used as raw material to prepare with sulfuric acid and bromine at high temperature, which also has strong corrosion and environmental protection problems. These methods have low yield, large pollution, and are not easy to operate. They have long been unable to meet the batch demand of modern materials.

Method used

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  • Preparation method of 4,5-dibromophthalic acid

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Experimental program
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Effect test

Embodiment 1

[0018] The preparation method of the 4,5-dibromophthalic acid of the present embodiment, the steps are as follows:

[0019] (1) Synthesis of dibromophthalic hydrazide: Add 16.20 g of phthalic hydrazide into a 250 mL three-necked round-bottomed flask with a reflux condenser, then pour 100 mL of glacial acetic acid into it, stir mechanically, and wait until Add 37.94g of NBS to it after all the solids are dissolved, a little heat will be given off during this process. After the system is stable, turn on the heating and control the temperature at 85°C. As the reaction progresses, the color of the solution gradually deepens, gradually changing from light yellow to yellow. After reacting for 1 h, the reaction solution was cooled, and then poured into ice water. After the ice melted, the precipitated solid was suction filtered to obtain a white solid. After drying, the quality after claiming its drying is 31.8g, and its yield is 99%

[0020] (2) Synthesis of 4,5-dibromophthalic ac...

Embodiment 2

[0023] The preparation method of the 4,5-dibromophthalic acid of the present embodiment, the steps are as follows:

[0024] (1) Synthesis of dibromophthalic hydrazide: Add 16.20 g of phthalic hydrazide into a 250 mL three-necked round-bottomed flask with a reflux condenser, then pour 100 mL of glacial acetic acid into it, stir mechanically, and wait until After all the solids are dissolved, 35.6g of NBS is added thereto, and a little heat will be released during this process. After the system is stable, turn on the heating and control the temperature at 85°C. As the reaction progresses, the color of the solution gradually deepens, gradually changing from light yellow to yellow. After reacting for 1 h, the reaction solution was cooled, and then poured into ice water. After the ice melted, the precipitated solid was suction filtered to obtain a white solid. After drying, the quality after claiming its drying is 30g, and its yield is 94%;

[0025] (2) Synthesis of 4,5-dibromoph...

Embodiment 3

[0027] The preparation method of the 4,5-dibromophthalic acid of the present embodiment, the steps are as follows:

[0028] (1) Synthesis of dibromophthalic hydrazide: Add 16.20 g of phthalic hydrazide into a 250 mL three-necked round-bottomed flask with a reflux condenser, then pour 100 mL of glacial acetic acid into it, stir mechanically, and wait until Add 37.94g of NBS to it after all the solids are dissolved, a little heat will be given off during this process. After the system is stable, turn on the heating and control the temperature at 85°C. As the reaction progresses, the color of the solution gradually deepens, gradually changing from light yellow to yellow. After reacting for 0.5 h, the reaction solution was cooled, and then poured into ice water. After the ice melted, the precipitated solid was suction filtered to obtain a white solid. After drying, the quality after claiming its drying is 28.8g, and its yield is 90%;

[0029] (2) Synthesis of 4,5-dibromophthalic...

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Abstract

The invention discloses a preparation method of 4,5-dibromophthalic acid. The preparation method comprises the following steps: (1) after dissolving phthalylhydrazine into glacial acetic acid, adding N-bromo-succinimide (NBS), heating the mixture to 80 to 100 DEG C and reacting for 0.5 to 1 hour; after the reaction is finished, cooling the system to a room temperature and pouring the mixture into ice water; separating out solids and filtering to obtain dibromophthalhydrazide and filtrate; (2) dissolving the dibromophthalhydrazide into a sodium hydroxide water solution, and heating the mixture to 60 to 70 DEG C and carrying out a hydrolysis reaction; after the hydrolysis reaction is finished, adjusting the pH of the hydrolysis reaction system to be 6 to 7; separating out white solids, and filtering and washing with water to prepare the 4,5-dibromophthalic acid. The preparation method of the 4,5-dibromophthalic acid has the advantages that the cost is low; products of two steps are both separated out in a solid manner; reaction is easy to treat and the purity of the products is high; industrial requirements on the products can be met completely, and sufficient raw materials are provided for research and development of downstream chemical products and materials.

Description

technical field [0001] The invention belongs to the field of organic synthesis chemistry, and in particular relates to a preparation method of 4,5-dibromophthalic acid. Background technique [0002] Phthalic acid compounds are excellent metal ligands and valuable organic intermediates, and are important raw materials for the synthesis of phthalocyanine compounds. Phthalocyanine has a large π-conjugated aromatic system and is used in sensors, cancer fluorescence therapy, dyes, optical Records, electrochromic smart materials and solar photovoltaic devices are widely used, especially dibromophthalic acid is an urgently needed raw material for the synthesis of bromophthalocyanine compounds, but 4,5-dibromophthalocyanine Formic acid is basically not sold in batches on the market, and the reported synthetic methods are mostly early literature (Chem.Ber., 1884,17: 2494-2496; J.Chem.Soc., 1952, 4615-4618; .Soc., 1942,64:2639-2641), nitric acid is often used to oxidize at a high tem...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/00C07C63/68
CPCC07C51/00C07D237/32C07C63/68
Inventor 靳清贤刘应凡吴诗德肖元化方少明丁瑞敏张悦凝李璐璐
Owner ZHENGZHOU UNIVERSITY OF LIGHT INDUSTRY
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