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Method for preparing toluene diisocynate from urea under catalysis of ionic liquid

A technology of toluene diisocyanate and ionic liquid, which is applied in the field of organic synthesis, can solve the problems of high cost, low yield, and environmental pollution, and achieve the effects of reducing production cost, good catalytic performance, and beneficial to industrial application

Active Publication Date: 2015-01-14
陕西煤业化工技术开发中心有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention solves the problems of high cost, low yield and environmental pollution in the TDI synthesis method in the prior art, and further provides a low cost, high yield, and environmentally friendly TDI synthesis method

Method used

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  • Method for preparing toluene diisocynate from urea under catalysis of ionic liquid
  • Method for preparing toluene diisocynate from urea under catalysis of ionic liquid
  • Method for preparing toluene diisocynate from urea under catalysis of ionic liquid

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Embodiment 1

[0026] The method for preparing toluene diisocyanate using ionic liquid catalysis described in this embodiment comprises the following steps:

[0027] (1) Under the protection of nitrogen, add 244.3g of 2,4-toluenediamine, 300.3g of urea and 0.43g of 1-hexyl-2,3-dimethylimidazolium chloride successively to a 1L autoclave, and heat up Melt the solid in the reactor to a liquid state at 150°C, keep the pressure at 1 MPa, start stirring and count. Follow up the reaction process by liquid chromatography, stop stirring after reacting for 3 hours, treat the reaction solution to be cooled to room temperature, discharge the residual ammonia in the reactor, the above reaction solution is carried out to liquid chromatography analysis, the result is as follows figure 1 As shown, the conversion rate of toluenediamine in the reaction solution of step (1) is 96.8%, and the yield of tolenediurea is 93.7%. Among them, the ionic liquid 1-hexyl-2,3-dimethylimidazolium chloride salt was purchase...

Embodiment 2

[0030] The method for preparing toluene diisocyanate using ionic liquid catalysis described in this embodiment comprises the following steps:

[0031] (1) Under nitrogen protection, 244.3g of 2,6-toluenediamine, 360.4g of urea and 1.9g of 1-ethyl-3-methylimidazolium bromide were added successively to a 1L autoclave, and the temperature was raised to 140 °C to completely melt the solid in the reactor into a liquid state, keep the pressure at 1.5 MPa, start stirring and count the time. Track the reaction process by liquid chromatography, stop stirring after reacting for 10 hours, treat the reaction solution to be cooled to room temperature, discharge the residual ammonia in the reactor, liquid chromatography analysis obtains the conversion ratio of toluene diamine in the step (1) reaction solution to be 90.8 %, the yield of toluene diurea is 83.1%. Among them, the ionic liquid 1-ethyl-3-methylimidazolium bromide was purchased from Sigma-Aldirch, CAS: 143314-16-3.

[0032] (2) ...

Embodiment 3

[0034] The method for preparing toluene diisocyanate using ionic liquid catalysis described in this embodiment comprises the following steps:

[0035](1) Under nitrogen protection, 195.4 g of 2,4-toluenediamine, 48.9 g of a mixture of 2,6-toluenediamine, 336.4 g of urea and 1-butyl-3- Methylimidazolium hexafluorophosphate 1.4g, heated up to 130°C to completely melt the solid in the reactor into a liquid state, keep the pressure at 2MPa, start stirring and timing. Track the reaction process by liquid chromatography, stop stirring after reacting for 6.5 hours, treat the reaction solution to be cooled to room temperature, discharge the residual ammonia in the reactor, liquid chromatography analysis obtains the conversion rate of toluene diamine in the step (1) reaction solution 96.2 %, the yield of toluene diurea is 94.8%. Among them, the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate was purchased from Sigma-Aldrich, CAS: 174501-64-5.

[0036] (2) Add the reactio...

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Abstract

The invention provides application of an ionic liquid in preparing toluene diisocynate and a method for preparing the toluene diisocynate from urea under the catalysis of the ionic liquid. The method is used for preparing the toluene diisocynate by taking toluenediamine and urea as the raw materials, reacting the raw materials to generate toluene diurea under the catalytic action of the ionic liquid and then pyrolyzing the toluene diurea. The method does not need highly toxic phosgene and an extra solvent; the ionic liquid is adopted as a catalyst; on one hand, the ionic liquid is good in catalytic effect, easy to remove and environment-friendly, and on the other hand, a metal catalyst in the prior art is not used, so that the reaction of the method for preparing the toluene diisocynate from urea under the catalysis of the ionic liquid does not require harsh device materials and operating conditions, consequently, the production cost is greatly reduced, and the method is advantageous to industrial application.

Description

technical field [0001] The invention relates to a method for preparing toluene diisocyanate through a non-phosgene method catalyzed by an ionic liquid, belonging to the field of organic synthesis. technical background [0002] Toluene diisocyanate (TDI) is an important raw material for the production of polyurethane. It is widely used in the synthesis of polyurethane foam, coatings, adhesives, pesticides and rubber. With the rapid development of the polyurethane industry, the demand for TDI is becoming more and more extensive. The traditional TDI synthesis method generally adopts the phosgene method (such as patent documents US3441586, CN103339105A, US8030522B2). The product hydrochloric acid corrodes equipment and other defects. Therefore, the development of a synthetic technology for the production of TDI by a non-phosgene method has positive practical significance and broad application prospects. [0003] Patent document WP0156977 discloses a method for preparing TDI wi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C263/06C07C265/14B01J31/02B01J31/04
Inventor 宋双田郑家威尚建选彭述先邬慧雄王振宇张蕾杨凯宁饶小峰赵迪
Owner 陕西煤业化工技术开发中心有限责任公司
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