Method for removing phosgene from isophthalylidene diisocyanate

A technology of iso-xylylene diisocyanate and phosgene, which is applied in the field of phosgene removal of iso-xylylene diisocyanate, can solve problems such as difficult removal of phosgene, improve safety and reduce load , the effect of reducing consumption

Active Publication Date: 2018-05-08
QINGDAO UNIV OF SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The novelty of the present invention is that the phosgene removal tower adopts a negative pressure operating system, which solves the difficult problem of m-xylylene diisocyanate phosgene removal

Method used

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  • Method for removing phosgene from isophthalylidene diisocyanate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] A mixed solution of amine and o-dichlorobenzene with a concentration of 4.8% and a flow rate of 1000kg / h, and phosgene at a temperature of -10°C and a flow rate of 278kg / h are subjected to a cold and hot photochemical reaction in the photochemical reactor 1. The HCL gas and excess phosgene generated after photochemistry are passed into the phosgene recovery system; the reacted photochemical liquid contains XDI, o-dichlorobenzene, phosgene and HCL, the temperature is 138°C, and the flow rate is 1481kg / h. The phosgene content is 2.5%, and the isocyanate content is 4.0%. The phosgene removal tower 2 is continuously fed into the phosgene removal tower 2 by the photochemical liquid discharge pump 6 for rectification. The operating pressure of the phosgene removal tower 2 is -0.2 barg; In addition to the mixed gas such as solvent and phosgene coming out of the top of the tower 2, it enters the first stage condenser 4 at the top of the tower, and its temperature is controlled a...

Embodiment 2

[0025] A mixed solution of amine and o-dichlorobenzene with a concentration of 4.8% and a flow rate of 1000kg / h, and phosgene at a temperature of -10°C and a flow rate of 278kg / h are subjected to a cold and hot photochemical reaction in the photochemical reactor 1. The HCL gas and excess phosgene generated after photochemistry are passed into the phosgene recovery system; the reacted photochemical liquid contains XDI, o-dichlorobenzene, phosgene and HCL, the temperature is 138°C, and the flow rate is 1481kg / h. The phosgene content is 2.5%, and the isocyanate content is 4.0%. The phosgene removal tower 2 is continuously fed into the phosgene removal tower 2 by the photochemical liquid discharge pump 6 for rectification. The operating pressure of the phosgene removal tower 2 is -0.1 barg; In addition to the mixed gas such as solvent and phosgene coming out of the top of tower 2, it enters the first stage condenser 4 at the top of the tower, and its temperature is controlled at 30...

Embodiment 3

[0027]A mixed solution of amine and o-dichlorobenzene with a concentration of 4.8% and a flow rate of 1000kg / h, and phosgene at a temperature of -10°C and a flow rate of 278kg / h are subjected to a cold and hot photochemical reaction in the photochemical reactor 1. The HCL gas and excess phosgene generated after photochemical pass into the phosgene recovery system; the reacted photochemical liquid contains XDI, o-dichlorobenzene, phosgene and HCL, its temperature is 139°C, and its flow rate is 1481kg / h. The phosgene content is 2.5%, and the isocyanate content is 4.0%. The phosgene removal tower 2 is continuously fed into the phosgene removal tower 2 by the photochemical liquid discharge pump 6 for rectification. The operating pressure of the phosgene removal tower 2 is -0.5 barg; In addition to the mixed gas such as solvent and phosgene coming out of the top of tower 2, it enters the first stage condenser 4 at the top of the tower, and its temperature is controlled at 50°C; the ...

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Abstract

The invention discloses a method for removing phosgene from isophthalylidene diisocyanate. The method includes the steps that isophthalylidene diisocyanate (XDI) actinic solution containing a high-boiling-point solvent enters a phosgene removal tower of a negative-pressure operation system, the temperature of the tower is adjusted to be proper to remove residue phosgene, then the temperature of atower top condenser is adjusted to condense the tower top solvent, the phosgene and other mixed gas at the same time, the phosgene is reduced as much as possible or prevented from entering a vacuum system, and tower top condensate serves as an absorbing agent to be used for a phosgene recycling system. The method is suitable for removing the phosgene by using the high-boiling-point solvent and theXDI with a heat sensitivity problem or similar isocyanate. The method is high in phosgene removing capacity, reduces the load of the vacuum system, reduces the consumption of a cryogenic medium, andomits the process that parts of solvents are specially removed to be used for the phosgene recycling system.

Description

technical field [0001] The invention belongs to the technical field of negative pressure phosgene removal, and relates to a phosgene removal method of m-xylylene diisocyanate. Background technique [0002] Meta-xylylene diisocyanate (XDI) has a benzene ring, and its two NCO groups are respectively connected to the benzene ring through a methylene group, so that the NCO group is prevented from being separated from the benzene ring due to the space between the methylene groups. The ring forms a resonance, which will not cause yellowing of polyurethane products. XDI is mainly used to prepare polyurethane materials for outdoor use, such as non-yellowing polyurethane products such as coatings, adhesives, and elastomers. The preparation method of XDI is mainly the liquid phase phosgenation method, and the photochemical liquid generated needs to be dephosgeneted before the next production process can be carried out. Traditional phosgene removal methods include pressurized or ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C263/10C07C263/20C07C265/14
CPCC07C263/10C07C263/20C07C265/14
Inventor 毕荣山谭心舜郑世清曾民成葛纪军
Owner QINGDAO UNIV OF SCI & TECH
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