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Draft tube type jet flow reactor and method for preparing isocyanate using the same

A technology of a jet reactor and a guide tube, which is applied in the direction of chemical methods, chemical instruments and methods, preparation of isocyanic acid derivatives, etc. to make gas medium react with gas medium, and can solve heat exchanger blockage and heat exchanger deposition , poor heat transfer, etc.

Active Publication Date: 2009-02-25
WANHUA CHEMICAL (NINGBO) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, the cooling and absorption of high-temperature gas can also be carried out through the heat exchanger, but long-term operation of the heat exchanger surface will deposit by-products, which will deteriorate the heat transfer and eventually lead to the blockage of the heat exchanger

Method used

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  • Draft tube type jet flow reactor and method for preparing isocyanate using the same
  • Draft tube type jet flow reactor and method for preparing isocyanate using the same
  • Draft tube type jet flow reactor and method for preparing isocyanate using the same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] 4,4'-dicyclohexylmethanediamine (HMDA), phosgene and nitrogen flowed into the reactor continuously through their respective feed pipes at a molar ratio of 1:4:1. The downstream of the reactor is connected with a gas jet absorber (for condensation) and an excess phosgene and hydrogen chloride absorption tower. HMDA, phosgene, and nitrogen enter the figure 1 The indicated reactor fronts were respectively preheated to 360°C. The HMDA vapor is diluted with nitrogen that is 1 times the molar number of the HMDA vapor to form a mixture, and then injected into the guide tube through 6 transverse holes opened on the wall of the inner feed tube, the transverse holes and the guide tube The inner diameter is 1.5mm, the inner diameter of the inner feeding pipe is 12mm, the inner diameter of the outer feeding pipe is 30mm, the inner diameter of the annular space 5 is 20mm, the distance between the transverse hole and the bottom of the annular space is 1cm, the distance between the t...

Embodiment 2

[0055] 4,4'-dicyclohexylmethanediamine (HMDA), phosgene and nitrogen are continuously flowed into such as figure 1 In the shown reactor, HMDA, phosgene, and nitrogen enter into such as figure 1The indicated reactor fronts were each preheated to 360°C. Using a reactor similar to Example 1, nitrogen and HMDA vapor are injected into the guide tube through 4 transverse holes opened on the wall of the inner feed tube, the inner diameter of the transverse holes and the guide tube is 2.0mm, and The inner diameter of the feeding tube is 12mm, and the inner diameter of the first dotted circle is 0.7 times of the inner diameter of the inner feeding tube, and other dimensions and conditions are the same as in Example 1. The vacuum in the reaction tube is -400mbar, the flow velocity of the amine vapor and nitrogen gas flowing through the transverse hole is about 34m / s, and the phosgene flow velocity before mixing is about 8m / s. After leaving the reaction tube of the reactor, the reactio...

Embodiment 3

[0057] Isophoronediamine (IPDA), phosgene and nitrogen enter in the reactor identical with embodiment 1 with the mol ratio of 1:4:1, before entering reactor, IPDA, phosgene and nitrogen are preheated earlier respectively To 320°C, under almost the same reaction conditions as in Example 1, the yield of IPDI was 98.8% of the theoretical value.

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PUM

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Abstract

The invention provides a draft tube-typed jet reactor and a method for preparing isocyanate with the reactor by a gas phase phosgenation process. A draft tube is arranged inside an inner feed tube of the draft tube-typed jet reactor to form a rotary stream which is reinforced into vortex flow, thus amine vapor and phosgene are quickly mixed and react to reduce the generation of by-products. In addition, by adopting a jet and absorption device, high-temperature gas discharged from the reactor is quickly cooled to a temperature at which the product is stable; meanwhile, negative pressure is provided for the system reaction process, thus avoiding a huge vacuum system.

Description

technical field [0001] The invention relates to a jet reactor, in particular to a draft tube type jet reactor, and also relates to a method for preparing isocyanate by using the draft tube type jet reactor. Background technique [0002] As early as the 1940s, there were reports on the preparation of isocyanates by gas-phase phosgenation (Siefken, Annalen 562, 108, 1949). Gas phase reaction processes are often carried out in tubular reactors. The gas phase reaction process is a fast reaction process, which requires a fast mixing rate and at the same time try to avoid high temperature coking. In the process of high-temperature gas-phase phosgenation reaction, amines and isocyanates are extremely unstable if they stay at a high temperature of 300-500°C for a long time, and such as removal of NH 2 , the decomposition reaction of NCO groups, so on the one hand, it is necessary to strengthen the mixing in the high temperature reaction process and shorten the residence time; Gas...

Claims

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Application Information

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IPC IPC(8): C07C263/10B01J12/00
Inventor 尚永华孙中平李建峰王勇华卫琦马德强王永胜丁建生
Owner WANHUA CHEMICAL (NINGBO) CO LTD
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