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A kind of tail gas treatment process of p-nitrobenzoyl chloride

A technology for nitrobenzoyl chloride and tail gas treatment, which is applied in the preparation of phosgene and organic compounds, chemical instruments and methods, etc., can solve the problems of increased energy consumption, long reaction time, increased impurities and separation operations, and saves cost, the effect of avoiding pollution

Active Publication Date: 2017-07-04
ANHUI GUANGXIN AGROCHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are certain deficiencies in the existing several preparation methods: as phosgene and phosphorus oxychloride are highly toxic substances, it is easy to cause harm to personnel safety and the environment; phosphorus pentachloride is a solid, and it is necessary to add a solvent to accelerate the reaction, which is easy Increase impurities and separation operations; when thionyl chloride is used as the chlorination agent, the reaction time is longer, and column distillation is required to remove impurities, increasing energy consumption, etc., so the direct discharge of the generated tail gas will cause environmental pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] First add toluene solution in the reaction kettle, fill the reaction kettle with phosgene, and at the same time continue to feed phosgene, the phosgene can be dissolved in the toluene solution, which can increase the reaction efficiency of phosgene and the remaining reactants, and Avoid the danger of explosion caused by direct reaction;

[0028] Add p-nitrobenzoic acid dropwise in the aforementioned reaction kettle again, stir while adding dropwise, until the pH value is 8, stop stirring, and stop feeding phosgene, the dropwise reaction improves the efficiency of the reaction, reduces the side reaction produced, and the reaction is very easy to control;

[0029] Then pass the aforementioned solution into the nitrogen gas for a flushing, and the amount of nitrogen gas introduced is 0.5L / s, and the reaction kettle is continuously stirred, which can drive out the tail gas in the reaction product, improve the purity of the product, and avoid phosgene, etc. Environmental po...

Embodiment 2

[0036] First add toluene solution in the reaction kettle, fill the reaction kettle with phosgene, and at the same time continue to feed phosgene, the phosgene can be dissolved in the toluene solution, which can increase the reaction efficiency of phosgene and the remaining reactants, and Avoid the danger of explosion caused by direct reaction;

[0037] Add p-nitrobenzoic acid dropwise in the aforementioned reaction kettle again, stir while adding dropwise, until the pH value is 9, stop stirring, and stop feeding phosgene, the dropwise reaction improves the efficiency of the reaction, reduces the side reaction produced, and the reaction is very easy to control;

[0038] Then pass the aforementioned solution into the nitrogen gas for a flushing, and the amount of nitrogen gas introduced is 0.6L / s, and the reaction kettle is continuously stirred, which can drive out the tail gas in the reaction product, improve the purity of the product, and avoid phosgene, etc. Environmental po...

Embodiment 3

[0045] First add toluene solution in the reaction kettle, fill the reaction kettle with phosgene, and at the same time continue to feed phosgene, the phosgene can be dissolved in the toluene solution, which can increase the reaction efficiency of phosgene and the remaining reactants, and Avoid the danger of explosion caused by direct reaction;

[0046] Add p-nitrobenzoic acid dropwise in the aforementioned reactor again, stir while adding dropwise, until the pH value is 10, stop stirring, and stop feeding phosgene, the dropwise reaction improves the efficiency of the reaction, reduces the side reaction produced, and the reaction is very easy to control;

[0047] Then pass the aforementioned solution into the nitrogen gas for a flushing, and the amount of nitrogen gas introduced is 0.7L / s, and the reaction kettle is continuously stirred, which can drive out the tail gas in the reaction product, improve the purity of the product, and avoid phosgene, etc. Environmental pollution...

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PUM

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Abstract

The invention provides an exhaust gas treatment process for paranitrobenzoyl chloride. The process comprises the following steps: adding a toluene solution into a reaction vessel, introducing phosgene into the reaction vessel, and meanwhile, continuing to introduce the phosgene; dropwise adding paranitrobenzoic acid into the reaction vessel, and carrying out stirring while carrying out dropwise adding; introducing nitrogen gas into the solution for first-time gas purging; drying gas subjected to first-time gas purging with a molecular sieve; introducing the dried gas into a recovery kettle, introducing chlorine gas into the recovery kettle, meanwhile, arranging an activated charcoal layer in the recovery kettle, and enabling a mixture of the dried gas and the chlorine gas to pass through the activated charcoal layer; introducing nitrogen gas into the recovery kettle for second-time gas purging, and then, carrying out phosgene extraction on gas subjected to second-time gas purging with a toluene or benzene solution; and introducing the extracted gas into a NaOH solution. According to the process, by adopting the process, exhaust gases, such as carbon monoxide, resulting from reactions can subject to a reaction again to produce the phosgene, and then, the phosgene is recovered.

Description

technical field [0001] The invention relates to the field of plastic fine chemical production, in particular to a tail gas treatment process of p-nitrobenzoyl chloride. Background technique [0002] p-Nitrobenzoyl chloride is a medical raw material used to prepare procaine hydrochloride, p-aminobenzoyl glutamic acid and folic acid, etc.; it can be used as a dye raw material to prepare direct dye brown 100 for leather and paper; It can be used to make acid dyes, food additives (milk powder conditioners), color developing agents and organic synthesis intermediates, identification of alcohols, phenolic reagents, etc. [0003] 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, with the rise of the feed industry and the development of the info...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C201/12C07C205/57C01B32/80
CPCC07C201/12C07C205/57
Inventor 过学军胡安胜吴建平高焰兵戴玉婷张军刘长庆徐小兵黄显超朱张
Owner ANHUI GUANGXIN AGROCHEM