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Refining process for p-nitrobenzoyl chloride

A technology of nitrobenzoyl chloride and p-nitrobenzoic acid, which is applied in the field of fine chemical separation, can solve the problems of long time, prominent safety hazard and high atmospheric boiling point, and achieves improved production efficiency, stable product quality and high yield Effect

Inactive Publication Date: 2017-06-20
SHANDONG KAISHENG NEW MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to facilitate transportation and downstream feeding and metering, it is generally necessary to slice it into flakes for supply. However, due to the very small amount of light component impurities such as thionyl chloride remaining, it will volatilize a strong irritant during the slicing and use process. Gas, harsh working environment, high labor intensity, greatly affect production efficiency and downstream market applications
Purification by rectification to remove the fore-distillation part can effectively remove the irritating odor during the slicing process. However, due to the high boiling point of p-nitrobenzoyl chloride at atmospheric pressure, the rectification process must be carried out under high vacuum conditions, and the temperature is high and the time is long. Side reactions inevitably occur, which have a great impact on product yield and production efficiency. At the same time, equipment operation investment and energy consumption are high, and safety hazards are prominent, resulting in high production costs. Therefore, it is urgent to develop a simple, efficient, and low-cost Refining process

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Put 1000kg of p-nitrobenzoic acid into the reaction kettle to react with excess thionyl chloride. After the reaction, unreacted thionyl chloride is distilled at atmospheric pressure until the temperature rises to 114°C, and no thionyl chloride Evaporate it, then carry out vacuum distillation, maintain the vacuum degree at 620±20mmHg, until the temperature rises to 122°C, no thionyl chloride is evaporated, stop the distillation, and lower the temperature to the boiling point of 1,2-dichloroethane Next, add 56kg of m-xylene and p-xylene with an organic solvent with a mass ratio of 1:1, stir evenly, and then carry out vacuum distillation to keep the system vacuum at 610 ± 20mmHg, and gradually increase the temperature to 100°C. The solvent was evaporated, the distillation was stopped, and finally 1104.5 kg of flaky p-nitrobenzoyl chloride was obtained by slicing, with a yield of 99.25%, a chromatographic purity of 99.49%, and no irritating odor of thionyl chloride.

Embodiment 2

[0018] Put 1000kg of p-nitrobenzoic acid into the reaction kettle to react with excess thionyl chloride. After the reaction, carry out atmospheric distillation to the unreacted thionyl chloride until the temperature rises to 111°C, and there is no thionyl chloride Distill it out, then carry out vacuum distillation on it, maintain the vacuum degree at 650±20mmHg, until the temperature rises to 123°C, no thionyl chloride is distilled out, stop the distillation, lower the temperature below the boiling point of toluene, add 85kg m-xylene The organic solvent with a mass ratio of 1:1 to p-xylene was stirred evenly, and then it was distilled under reduced pressure, and the vacuum degree of the system was maintained at 630±20mmHg, and the temperature was gradually increased to 120°C to evaporate without solvent, and the distillation was stopped. After slicing, 1104.9 kg of flaky p-nitrobenzoyl chloride was obtained, with a yield of 99.63%, a chromatographic purity of 99.64%, and no pun...

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PUM

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Abstract

The invention belongs to the technical field of fine chemical separation, and in particular relates to a process for refining p-nitrobenzoyl chloride. The refining process of p-nitrobenzoyl chloride of the present invention mainly aims at the synthesis of p-nitrobenzoyl chloride by the sulfur oxychloride method, and its concrete steps are to first react p-nitrobenzoic acid and excess thionyl chloride, After completion of the reaction, the thionyl chloride was removed by distillation under normal pressure and under reduced pressure, and an organic solvent with a mass ratio of m-xylene and p-xylene of 1:1 was added, and the solvent and remaining light component impurities were removed by distillation under reduced pressure. Finally, the flaky p-nitrobenzoyl chloride product is obtained by slicing. This process avoids the traditional long-term high-vacuum high-temperature distillation and purification process, and the production efficiency is greatly improved, and the product quality is stable, the yield is high, and the energy consumption is low.

Description

technical field [0001] The invention belongs to the technical field of fine chemical separation, and in particular relates to a process for refining p-nitrobenzoyl chloride. Background technique [0002] p-Nitrobenzoyl chloride is an important intermediate in the synthesis of folic acid, procaine hydrochloride, N-p-aminobenzoyl-L-glutamic acid and other vitamin pharmaceutical products, and is also widely used in the production of pigments and color developers . Especially in recent years, folic acid has developed rapidly as a feed additive, and p-nitrobenzoyl chloride is an important raw material for producing folic acid. The market demand has risen sharply, and the requirements for product quality are also getting higher and higher. [0003] At present, the production of p-nitrobenzoyl chloride mainly adopts the thionyl chloride method, that is, the reaction of p-nitrobenzoic acid and excess thionyl chloride is used to prepare p-nitrobenzoyl chloride. This method has the c...

Claims

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Application Information

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IPC IPC(8): C07C205/57C07C201/12C07C201/16
CPCC07C201/12C07C201/16
Inventor 张泰铭王荣海张善民毕义霞李文娟贾远超
Owner SHANDONG KAISHENG NEW MATERIALS