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Recycling method for phosgene in tail gas generated in calorescence reaction for synthesizing normal-butyl isocyanate

A technology of n-butyl isocyanate and light reaction, which is applied in the field of resource recycling and environmental protection, can solve the problems of large pollution, large material loss, and high equipment investment, and achieve the effect of less equipment investment, less waste acid, and reduced equipment investment

Active Publication Date: 2014-03-19
HUNAN GOFAR FINE CHEM IND TECH CO LDT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to overcome the disadvantages of high equipment investment, large material loss and large pollution in the tail gas falling film absorption method in the production process of n-butyl isocyanate, and provide a method for recycling phosgene in the tail gas of n-butyl isocyanate thermo-optic reaction , under the premise of ensuring that the recovery of phosgene is qualified, maximize the use of phosgene resources, reduce energy consumption, reduce costs, and reduce environmental pollution

Method used

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  • Recycling method for phosgene in tail gas generated in calorescence reaction for synthesizing normal-butyl isocyanate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] The tail gas from the thermo-optic reaction of synthetic n-butyl isocyanate is continuously absorbed by a solvent at -8°C to -2°C, and then condensed by a condenser, and the uncondensed gas directly enters the tail gas treatment system. The solvent has been absorbed at low temperature for many times. When the concentration of phosgene in the solvent xylene reaches 45%, it is directly applied to the luminescence reaction. First, 3000L of the phosgene-containing solvent is transferred to the luminescence kettle, and n-butylene is added dropwise at -8°C to -2°C. Amine, when continuing to add n-butylamine dropwise, temperature drops significantly, reaches the amount of n-butylamine needed for reaction metering, stops dripping, keeps warm for 1 hour, obtains n-butylamyl chloride, and its content is 92.36% in analysis. Add n-butylamine acid chloride and solvent into thermo-optical reactor and n-butylamine hydrochloride to prepare n-butylisocyanate.

Embodiment 2

[0030] The tail gas from the thermo-optic reaction of synthetic n-butyl isocyanate is continuously absorbed by a solvent at -8°C to -2°C, and then condensed by a condenser, and the uncondensed gas directly enters the tail gas treatment system. The solvent has been absorbed at low temperature for many times. When the concentration of phosgene in the solvent xylene reaches 48%, it is directly applied to the luminescence reaction. First, 3000L of the light-containing solvent is transferred to the luminescence kettle, and n-butylamine is added dropwise at -10℃~-2℃. , when continuing to add n-butylamine dropwise, the temperature drops significantly until the amount of n-butylamine needed for reaction metering is reached, the dripping is stopped, and the insulation is kept for 1 hour to obtain n-butylamyl chloride, whose content is 93.56% in analysis. Add n-butylamine acid chloride and solvent into thermo-optical reactor and n-butylamine hydrochloride to prepare n-butylisocyanate.

Embodiment 3

[0032] The tail gas from the thermo-optic reaction of synthetic n-butyl isocyanate is continuously absorbed by a solvent at -8°C to -2°C, and then condensed by a condenser, and the uncondensed gas directly enters the tail gas treatment system. The solvent has been absorbed at low temperature for many times. When the concentration of phosgene in the solvent xylene reaches 50%, it is directly applied to the luminescence reaction. First, 3000L of the light-containing solvent is transferred to the luminescence kettle, and n-butylamine is added dropwise at -8°C to 0°C. When continuing to add n-butylamine dropwise, the temperature dropped significantly until the amount of n-butylamine needed for reaction metering was reached, then the dripping was stopped, and the temperature was kept for 1 hour to obtain n-butylamine acid chloride, whose content was analyzed to be 95.32%. Add n-butylamine acid chloride and solvent into thermo-optical reactor and n-butylamine hydrochloride to prepare...

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Abstract

The invention relates to a recycling method for phosgene in tail gas generated in calorescence reaction for synthesizing normal-butyl isocyanate. The recycling method comprises the steps of continuously cooling and absorbing the tail gas generated in the calorescence reaction for synthesizing the normal-butyl isocyanate through a low temperature solvent, and condensing the tail gas through a condenser, wherein the non-condensing gas directly enters a tail gas processing system; preparing normal-butyl acyl chloride from the solvent containing the phosgene with certain quality concentration through cold light reaction, metering the phosgene-containing solvent, shifting the solvent into a cold light kettle, dropwise adding n-butylamine at -8 DEG C to -2 DEG C, after the dropwise adding, keeping the temperature for 1 hour so as to obtain the n-butylamine acyl chloride; and resolving the n-butylamine acyl chloride in a calorescence reaction kettle to obtain the normal-butyl isocyanate. The method provided by the invention has the advantages that the phosgene is utilized to the greatest extent, the load of the tail gas generated in the normal-butyl isocyanate calorescence reaction in a tail gas processing system and the alkali charge during tail gas processing are reduced, the production cost of the product is reduced, and the purpose of saving and recycling resources is achieved.

Description

technical field [0001] The invention belongs to the field of resource recycling and environmental protection, and in particular relates to a method for recycling phosgene in the tail gas of thermo-light reaction of synthetic n-butyl isocyanate. This method can purify and separate the phosgene in the tail gas of the thermo-optical reaction of synthetic n-butyl isocyanate, and the purified and separated phosgene can be directly used in the luminescence process of n-butyl isocyanate for recycling, and most of the other gases after purification and separation are treated by the tail gas system Recovery of by-product hydrochloric acid. The method can maximize the utilization of phosgene, reduce the load of n-butyl isocyanate thermo-optic reaction tail gas in the tail gas treatment system and the amount of alkali used for tail gas treatment, reduce the production cost of products, and achieve the purpose of resource saving and recycling. Background technique [0002] At present, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D5/00B01D53/78B01D53/68B01D53/14C01B31/28C07C265/04C07C263/04C01B32/80
Inventor 胡晓珊张敦河黎辉良李国栋余建波沈方勇甘爱玲
Owner HUNAN GOFAR FINE CHEM IND TECH CO LDT
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