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Process of preparing 4-nitro phthalic acid from the reaction mother liquor of nitrating phthalic anhydride to prepare 3-nitro phthalic acid

A nitrophthalic acid and reaction technology, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry and other directions, can solve problems such as cumbersome methods, difficult to apply in industrial production, etc., and achieve environmental protection and resource utilization. Effect

Inactive Publication Date: 2006-03-01
潘健
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But this method is very cumbersome and not easy to apply in industrial production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] A. Nitrification

[0014] Add 237.5g of concentrated sulfuric acid to a dry 500ml three-necked flask, start the agitator, then add 112.5g of fuming nitric acid, heat up to 55°C, stop heating, and slowly add 125g of phthalic anhydride in batches (in 4 times). The reaction temperature was controlled at 70-80°C, and the addition was completed in about 1.5 hours. Then react at 75-80°C for 3 hours, and then react at 80-85°C for 1 hour. Cool to room temperature after the reaction.

[0015] B. Filtration and separation

[0016] The reaction solution in step A is sucked and filtered, and the crystals are filtered out to obtain 96.5 g of filter cake as 3-nitrophthalic acid (I); 200 ml (345.6 g) of the filtrate mainly contains 4-nitrophthalic acid (II )

[0017] Preparation of C, 3-nitrophthalic acid

[0018] Add (I) to 2.5 times the mass of water, heat to dissolve, cool to room temperature, precipitate crystals, suction filter, and dry the filter cake to obtain 50.5 g of cr...

Embodiment 2

[0022] A. Nitrification

[0023] Add 237.5g of concentrated sulfuric acid to a dry 500ml three-necked flask, start the agitator, then add 112.5g of fuming nitric acid, heat up to 55°C, stop heating, and slowly add 125g of phthalic anhydride in batches (in 4 times). The reaction temperature was controlled at 70-80°C, and the addition was completed in about 1.5 hours. Then react at 75-80°C for 3 hours, and then react at 80-85°C for 1 hour. Cool to room temperature after the reaction.

[0024] B. Filtration and separation

[0025] Suction filter the reaction solution in step A, filter out the crystals, and obtain 96.5 g of filter cake as 3-nitrophthalic acid

[0026] (I); Filtrate 200ml (345.6g) mainly contains 4-nitrophthalic acid (II)

[0027] Preparation of C, 3-nitrophthalic acid

[0028] Add (I) to 3 times the mass of water, heat to dissolve, cool to room temperature, precipitate crystals, suction filter, and dry the filter cake to obtain 47.6 g of crude product 3-nitro...

Embodiment 3

[0032] A. Nitrification

[0033] Add 237.5g of concentrated sulfuric acid to a dry 500ml three-necked flask, start the agitator, then add 112.5g of fuming nitric acid, heat up to 55°C, stop heating, and slowly add 125g of phthalic anhydride in batches (in 4 times). The reaction temperature was controlled at 70-80°C, and the addition was completed in about 1.5 hours. Then react at 75-80°C for 3 hours, and then react at 80-85°C for 1 hour. Cool to room temperature after the reaction.

[0034] B. Filtration and separation

[0035] The reaction solution in step A is sucked and filtered, and the crystals are filtered out to obtain 96.5 g of filter cake as 3-nitrophthalic acid (I); 200 ml (345.6 g) of the filtrate mainly contains 4-nitrophthalic acid (II )

[0036] Preparation of C, 3-nitrophthalic acid

[0037] Add (I) to 3.5 times the mass of water, heat to dissolve, cool to room temperature, precipitate crystals, filter with suction, and dry the filter cake to obtain 46g of ...

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Abstract

The process of preparing 4-nitro phthalic acid from the reaction mother liquor of nitrating phthalic anhydride to prepare 3-nitro phthalic acid consists of the following steps: 1. adding the mother liquor into 1.5-3.5 times of cold water, letting stand over night and filtering to operate coarse 4-nitro phthalic acid product; 2. dissolving the coarse product in 2.5-3.5 times of water and stirring at normal temperature for completely dissolving; 3. adding nitric acid in the amount of 0.08-0.12 time the solution into the solution, extracting 4-nitro phthalic acid with ethyl ether to obtain ethyl ether extract liquid; and 4. evaporating the ethyl ether extract liquid to eliminate ethyl ether, and cooling to crystallize and to obtain 4-nitro phthalic acid. The present invention has high purity and high yield of 4-nitro phthalic acid.

Description

technical field [0001] The present invention relates to the preparation of 4-nitrophthalic acid. Background technique [0002] During the nitration of phthalic anhydride to prepare 3-nitrophthalic acid, the by-product 4-nitrophthalic acid must be produced. Due to the high solubility of 4-nitrophthalic acid in water, 3-nitrophthalic acid can be obtained by filtration, and 4-nitrophthalic acid is discarded (see: Editor-in-Chief Gell-Mann, Nanjing University Organic Translated by teaching and research group, "Organic Synthesis" first episode, 329, 1957, Science Press). This not only wastes resources, but also pollutes the environment. In order to obtain 4-nitrophthalic acid, it needs to be prepared by hydrolysis of 4-nitrophthalimide (see: Editor-in-Chief Gellman, translated by the Organic Teaching and Research Group of Nanjing University, "Organic Synthesis" 1st collection, 311, 1957, Science Press). U.S. Patent U.S.P4284797 discloses a method for separating and preparing ...

Claims

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Application Information

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IPC IPC(8): C07C205/57C07C201/16
Inventor 潘健
Owner 潘健
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