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A kind of method for preparing low-chlorinated impurity content isocyanate based on salt-forming phosgenation

A technology of isocyanate and impurity content, applied in the field of isocyanate, can solve the problems of low reaction conversion rate, many side reactions, incomplete hydrochloride salt formation, etc., and achieve high yield and simple operation

Active Publication Date: 2022-08-05
WANHUA CHEM GRP CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] In order to overcome the problems of low reaction conversion rate, incomplete hydrochloride salt formation, many side reactions, especially high content of chlorinated impurities in the existing photochemical process of isocyanate salt formation, it is necessary to improve the existing process

Method used

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  • A kind of method for preparing low-chlorinated impurity content isocyanate based on salt-forming phosgenation
  • A kind of method for preparing low-chlorinated impurity content isocyanate based on salt-forming phosgenation
  • A kind of method for preparing low-chlorinated impurity content isocyanate based on salt-forming phosgenation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0064] Drop into 40kg chlorobenzene as the reaction solvent of bottoming in the reaction kettle, open the reaction kettle and stir, the set rotating speed is 200rpm, and 3.2kg (23.5mol) m-xylylenediamine is added in the reactor as a separate stream (The corresponding total amine concentration of the salt-forming reaction solution is 8 wt%). At the beginning of the reaction and during the process, the temperature in the salt-forming reactor was controlled to be 10° C., and the pressure of the reactor was adjusted to 0.1 MPa (absolute pressure). The solutions of the hydrogen chloride gas and the amine stream were divided at 1.1 Nm 3 The flow rate of / h and 2.3kg / h was passed into the salt-forming reaction kettle. After 1.5h, the passing of hydrogen chloride and amine streams was stopped, and the salt-forming reaction was completed. After the salt-forming reaction is completed, sample the particle size of the test sample, keep the stirring state, and use a laser diffraction part...

Embodiment 2

[0067] Drop into 10kg o-dichlorobenzene as the reaction solvent for priming in the reactor, drop into 4.0kg (37mol) p-phenylenediamine and 30kg o-dichlorobenzene in the raw material tank and be configured to be a 13% amine stream suspension ( The corresponding total amine concentration of the salt-forming reaction solution is 10 wt%). The temperature in the reactor was controlled to be 100°C, the pressure of the reactor was adjusted to 0.15MPa (absolute pressure), and the stirring speed of the reactor was adjusted to 200rpm. The suspensions of the hydrogen chloride gas and the amine stream were respectively charged at 4.14 Nm 3 The flow rates of / h and 34kg / h were passed into the salt-forming reactor, and the hydrogen chloride and amine streams were stopped after 1.0h, and the salt-forming reaction was completed. Particles with diameters between 5.60 and 10.40 microns (8.0 microns ± 30%) accounted for 76.99% of all particle size distributions. Transfer the amine hydrochlorid...

Embodiment 3

[0070] Drop into 15kg of chlorobenzene as the reaction solvent for bottoming in the reactor, drop into the raw material tank 8.0kg (69mol) of 1,6-hexanediamine and 25kg of chlorobenzene to configure the concentration of 32% amine stream solution (corresponding to The total amine concentration of the salt-forming reaction solution is 20 wt%). The temperature in the salt-forming reactor was controlled to be 40° C., the pressure of the reactor was adjusted to 0.20MPa (absolute pressure), and the stirring speed of the reactor was adjusted to 200rpm. The solutions of the hydrogen chloride gas and the amine stream were divided at 6.18 Nm 3 The flow rates of / h and 16.5kg / h were passed into the salt-forming reaction kettle, the hydrogen chloride and amine streams were stopped after 2.0h, the salt-forming reaction was completed, and the average particle size of the hydrochloride particles obtained by sampling and testing was 12.0 microns, Particles with a particle size between 8.40 a...

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Abstract

The invention provides a method for preparing isocyanate with low chlorinated impurity content based on a salt-forming phosgenation method. The ratio of the particle size distribution of the salt particles obtained by the salt-forming reaction in the method within the range of average particle size ±30% accounts for more than 70% of the total particle size distribution, and the average residence time without stirring is less than 60 minutes. Compared with the traditional method, the product obtained by this method has a lower content of chlorinated impurities.

Description

technical field [0001] The invention belongs to the field of isocyanates, and in particular relates to a method for preparing isocyanates with low chlorinated impurity content based on a salt-forming phosgenation method. Background technique [0002] In the prior art, a phosgenation method for preparing isocyanates by reacting organic primary amines with phosgene in an inert solvent is well known. The phosgene method can be divided into the direct method and the salt-forming method. The direct method is to prepare the corresponding isocyanate by directly reacting primary amine and phosgene. The salt-forming method first reacts the corresponding amine with an acidic gas such as hydrogen chloride, carbon dioxide, etc. to prepare the amine. salt and then react the amine salt with phosgene. For the direct method, due to the fast reaction rate of some amines and phosgene, it is easy to cause amine coating and produce urea by-products in the subsequent thermal photochemical proce...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C263/10C07C265/14C07C209/74C07C211/50C07C211/51C07C211/12C07C211/36C07C211/58
CPCC07C263/10C07C265/14C07C209/74C07C211/50C07C211/51C07C211/12C07C211/36C07C211/58C07C2601/14
Inventor 李同和王京旭孙淑常崔学磊郝超张翼强何伟郭耀允方婷尚永华
Owner WANHUA CHEM GRP CO LTD
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