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Method for preparing p-nitrobenzoic acid through oxygen oxidation of paranitrotoluene in absence of catalyst

A technology of p-nitrobenzoic acid and p-nitrotoluene, which is applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve problems such as catalyst synthesis difficulties, industrial application limitations, explosion hazards, etc., and achieve cheap recovery. The effect of reuse, easy recycling and reuse, easy production control

Active Publication Date: 2018-07-03
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this type of method is that the use of anhydrous methanol or methanol-benzene as a solvent, anhydrous methanol operating (reaction or distillation) under pure oxygen conditions has a potential explosion hazard, and methanol is very toxic to the optic nerve; In addition, benzene has great blood toxicity and neurotoxicity, which is a potential threat to the health of laboratory or industrial operators.
In the above public reports, metal metal phthalocyanines or metal porphyrins are required as catalysts. Due to the problems of low yield, difficult separation and purification, and the need to consume a large amount of organic solvents in the synthesis of such catalysts, their industrial applications are limited.
[0004] To sum up, whether it is the traditional chemical oxidation method, catalytic oxidation method, or biomimetic catalytic oxidation method, there are still problems such as heavy metal pollution, environmental pollution, or difficulty in the synthesis of catalysts, which limit its industrial application. Especially for heavy metal residue requirements and its strict pharmaceutical and food industry fields

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Embodiment 1: get p-nitrotoluene (823mg, 6mmol), sodium hydroxide (1.8g, 45mmol), add in the 100ml autoclave, add methyl alcohol 10ml; After filling and changing oxygen three times, pass into oxygen (pressure 1.8MPa), The reaction was carried out at 55° C. in an oil bath for 24 hours. After the reaction, add methanol for dilution, neutralize the pH value of the reaction mixture to 2-3, remove most of the solvent under reduced pressure, add ethyl acetate, dry and filter. After chromatographic column separation, 33mg (0.24mmol) of p-nitrotoluene was recovered, the conversion rate of p-nitrotoluene was 96%, and 722mg (4.32mmol) of p-nitrobenzoic acid was obtained, with a yield of 72%.

Embodiment 2

[0024] Embodiment 2: Get p-nitrotoluene (823mg, 6mmol), sodium hydroxide (1.8g, 45mmol), add in the 100ml autoclave, add methyl alcohol 10ml; After filling and changing oxygen three times, pass into oxygen (pressure 1.8MPa), React in an oil bath at 65°C for 24 hours. After the reaction, add methanol for dilution, neutralize the pH value of the reaction mixture to 2-3, remove most of the solvent under reduced pressure, add ethyl acetate, dry and filter. After chromatographic column separation, 131.7mg (0.96mmol) of p-nitrotoluene was recovered, the conversion rate of p-nitrotoluene was 84%, and 591.6mg (3.54mmol) of p-nitrobenzoic acid was obtained, with a yield of 59%.

Embodiment 3

[0025] Embodiment 3: get p-nitrotoluene (823mg, 6mmol), sodium hydroxide (1.8g, 45mmol), add in the 100ml autoclave, add methanol 10ml, after charging and changing oxygen three times, pass into oxygen (pressure 0.1MPa), React in an oil bath at a temperature of 55° C. for 2.5 h. After the reaction, add methanol for dilution, neutralize the pH value of the reaction mixture to 2-3, remove most of the solvent under reduced pressure, add ethyl acetate, dry and filter. After chromatographic column separation, 98.7 mg (0.72 mmol) of p-nitrotoluene was recovered, the conversion rate of p-nitrotoluene was 88%, and 180.5 mg (1.08 mmol) of p-nitrobenzoic acid was obtained, with a yield of 18%.

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Abstract

The invention discloses a method for preparing p-nitrobenzoic acid through oxygen oxidation of paranitrotoluene in absence of a catalyst and relates to a preparation method of p-nitrobenzoic acid. Themethod comprises the following steps: under a condition that any catalyst is not added, by taking paranitrotoluene as a raw material, taking oxygen of 0.1-2.0MPa as an oxidizing agent and taking sodium hydroxide as base, reacting in alcohol or an aqueous solution thereof at a reaction temperature of 25-65 DEG C; and performing after-treatment, separating and purifying, thereby obtaining the p-nitrobenzoic acid. According to the method, any catalyst is not needed; the price of the raw material and solvent is low; the reaction temperature is moderate; and the product is easy for production control, has the yield of 90% or higher, is suitable for large-scale preparation and industrialization and has wide application prospects.

Description

technical field [0001] The invention relates to a preparation method of p-nitrobenzoic acid, in particular to a method for preparing p-nitrobenzoic acid by oxygen oxidation of p-nitrotoluene without a catalyst. Background technique [0002] p-Nitrobenzoic acid is an important intermediate in organic synthesis, widely used in dyes, medicine, food, organic synthesis and other fields. At present, the methods for synthesizing p-nitrobenzoic acid are mainly potassium permanganate oxidation, sodium bicarbonate oxidation, NaClO oxidation, nitric acid oxidation or adding other pre-transition metals and noble metal catalyst oxidation (Letters inDrug Design & Discovery, 2013, 10,369; Applied Organometallic Chemistry, 2015, 29, 276; Tetrahedron, 2012, 68, 9763; Catalysis Communications, 2012, 27, 124; Hangzhou Chemical Industry, 1996.2.44), the oxidants used in these methods are strong oxidants, and there are heavy metals that seriously pollute the environment At the same time, it als...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/12C07C205/57
CPCC07C201/12C07C205/57
Inventor 佘远斌方坤李贵杰付海燕
Owner ZHEJIANG UNIV OF TECH
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