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Method for synthesizing p-nitrobenzoic acid

A technology of p-nitrobenzoic acid and p-nitrotoluene, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of low production cost, high production cost, unfavorable industrial production, etc. The effect of simple operation, reduced production cost and reduced production risk

Inactive Publication Date: 2019-01-18
浙江优创材料科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The former uses glacial acetic acid as a solvent, the equipment is severely corroded, the solvent consumption is large, and the solvent is difficult to recycle and reuse. In addition, a heavy metal catalyst is required, which causes great environmental pollution and high production costs; the latter has low production costs and simple post-processing of the product. However, the pressure required for the reaction is high, and the amount of waste gas and waste acid is limited by many environmental protection regulations, so it is difficult to meet the needs of the existing market.
[0003] Patent CN 1524842 discloses a kind of using p-nitrotoluene as reaction raw material, cobalt acetate as catalyst, azobisisobutyronitrile as initiator and oxygen as oxidant to prepare p-nitrobenzoic acid in a mixed solvent of acetic acid and dichlorotoluene The method utilizes dichlorotoluene to slow down the corrosion of acetic acid to equipment, but the reaction time is long and the yield is low, which is not conducive to industrial production
Patent US 20080139841 has improved the system of cobalt acetate-oxygen oxidation p-nitrotoluene, although the yield has been improved, but the method uses acetic acid as solvent, acetic acid is extremely corrosive to equipment, and acetic acid has a high boiling point and is difficult to recover. Agent N-hydroxyphthalimide price is high, generally speaking, the production cost of this method is high, and the market competitive advantage is not obvious
[0004] The nitric acid oxidation method in the prior art uses dilute nitric acid as a single oxidant. During the reaction process, dilute nitric acid is reduced to nitric oxide gas, resulting in a sharp increase in pressure, which requires continuous exhaust and pressure relief. The entrained material is easy to block the pressure relief valve during pressure relief. Cause safety hazards, the amount of waste gas discharged is large and difficult to handle, and the reaction mother liquor cannot be reused, and the high cost of waste gas and waste acid treatment limits the application of this method

Method used

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  • Method for synthesizing p-nitrobenzoic acid
  • Method for synthesizing p-nitrobenzoic acid
  • Method for synthesizing p-nitrobenzoic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0026] Put p-nitrotoluene (32.00 g, 233.34 mmol) and dilute nitric acid solution containing 20% ​​nitric acid (containing 536.68 mmol of nitric acid) in a 500 mL autoclave, replace the air in the autoclave with 0.5 MPa oxygen for 4 times, and fill it with oxygen When the pressure reaches 1.0 MPa, start stirring, raise the temperature to 170 °C, stir and react for 1.5 h, stop heating (when the pressure reaches or falls below 0.8 MPa during the reaction, add oxygen to 1.0 MPa in time), cool, filter with suction, and collect the mother liquor for recycling , the filter cake was rinsed with water to neutrality, dried to obtain 36.89 g of light yellow solid, and the purity of the product was 99.88% (high performance liquid chromatography, liquid method Agilent1260 LC liquid chromatograph, area normalization method, chromatographic column Z0RBAX SB-C18, 5 μm, 4.6×250 mm, elution condition: V (methanol): V (water containing 0.8% acetic acid) = 30:70 (0min) → 60:40 (20min) → 60:40 ( 2...

Embodiment 2

[0028] Put p-nitrotoluene (32.00 g, 233.34 mmol) and dilute nitric acid solution containing 10% nitric acid (containing 233.34 mmol of nitric acid) in a 500 mL autoclave, replace the air in the autoclave with 0.6 MPa oxygen for 4 times, and fill it with oxygen When the pressure reaches 2.0 MPa, start stirring, raise the temperature to 230 °C, stir and react for 14.0 h, stop heating (when the pressure is lower than 2.0 MPa during the reaction, add oxygen to 2.0 MPa in time), cool, filter with suction, collect the mother liquor for recycling, filter The cake was rinsed with water until neutral, and dried to obtain 37.42 g of a light yellow solid. The purity of the product was 99.79%, the yield of the product was 95.75%, and the volume of the mother liquor was 148.1 mL.

Embodiment 3

[0030] Put p-nitrotoluene (32.00 g, 233.34 mmol) and dilute nitric acid solution containing 40% nitric acid (containing 933.36 mmol of nitric acid) in a 500 mL autoclave, replace the air in the autoclave with 0.4 MPa oxygen 4 times, and fill it with oxygen When the pressure reaches 0.4 MPa, start stirring, raise the temperature to 120 °C, stir and react for 1.0 h, stop heating (when the pressure is lower than 0.4 MPa during the reaction, add oxygen to 0.4 MPa in time), cool, filter with suction, collect the mother liquor for recycling, filter The cake was rinsed with water until neutral, and dried to obtain 36.11 g of a light yellow solid. The purity of the product was 99.99%, the yield of the product was 92.58%, and the volume of the mother liquor was 135.3 mL.

[0031] The following is the implementation of the mother liquor

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Abstract

The invention relates to the field of production of chemical engineering products, in particular to a method for synthesizing p-nitrobenzoic acid. The method comprises the following steps of using p-nitrotoluene as the raw material, using diluted nitric acid as a reaction medium and a catalyst, using oxygen as an oxidant, and oxidizing in a high-pressure kettle, so as to prepare the p-nitrobenzoicacid; cooling, separating crystal form solid in the reaction liquid, sucking and filtering, so as to obtain a mother liquid and filter cake; spraying the filter cake by water, and drying, so as to obtain a light yellow product, namely p-nitrobenzoic acid. The method for synthesizing the p-nitrobenzoic acid has the advantages that the production purity is high, the preparation is simple, the costis low, the pollution is avoided, and the green effect is realized.

Description

technical field [0001] The invention relates to the field of chemical product production, in particular to a method for synthesizing p-nitrobenzoic acid. Background technique [0002] p-Nitrobenzoic acid is a widely used medicine, pesticide and dye intermediate, it is mainly used in the synthesis of insecticides and antifungal Anesthetics such as benzoic acid and procainamide can also be used as raw materials for organic synthesis, dyes and color films, and have broad market prospects. At present, there are two main processes for industrially synthesizing p-nitrobenzoic acid: liquid-phase catalytic oxygen oxidation and nitric acid oxidation. The former uses glacial acetic acid as a solvent, the equipment is severely corroded, the solvent consumption is large, and the solvent is difficult to recycle and reuse. In addition, a heavy metal catalyst is required, which causes great environmental pollution and high production costs; the latter has low production costs and simple p...

Claims

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Application Information

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IPC IPC(8): C07C201/12C07C205/57
CPCC07C201/12C07C205/57
Inventor 吴建龙朱晓东冯东李益珠贾建洪
Owner 浙江优创材料科技股份有限公司
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