Preparation of (poly) isocyanic ester in gas phase

A technology of steam and air flow, which is applied in the field of continuous preparation of isocyanate, can solve the problems of unsatisfactory service life of the reactor, etc., and achieve the effects of increasing relative yield, reducing residence time, and reducing heat load of products

Inactive Publication Date: 2004-09-22
COVESTRO DEUTSCHLAND AG
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Problems solved by technology

However, the reactor service life obtained with this arrangement is still not fully satisfactory

Method used

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  • Preparation of (poly) isocyanic ester in gas phase
  • Preparation of (poly) isocyanic ester in gas phase
  • Preparation of (poly) isocyanic ester in gas phase

Examples

Experimental program
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Effect test

Embodiment 2

[0046] exist figure 2 The preparation of isocyanate is carried out in the combined mixing reaction tube 2 shown, followed by the isocyanate condensation step, through the multi-nozzle with 6 independent nozzles 5, 2,4-toluenediamine / 2 with a molar ratio of 1:6:0.2 is continuously added, The isomer mixture (TDA80 / 20) of 6-toluenediamine, phosgene and nitrogen, the above-mentioned nozzles are arranged in a ring shape, all extend into the reaction tube 2 . Each educt was evaporated separately in pure form and heated to 340-370° C. in a preheat exchange step. The mixture (E1) of nitrogen and TDA flows in through six separate nozzles 5 arranged in a ring shape, and the phosgene (E2) flows in from the remaining space 6 around the independent nozzles 5 . The ratio of the cross-sectional area of ​​the reaction chamber 8 to the total area of ​​the six independent nozzles 5 is 192:1 (as in Comparative Example 1). The pressure in the reaction zone was 1.5 bar. After passing through t...

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Abstract

The present invention relates to a process for the manufacture of diisocyanates by phosgenation of the corresponding diamines in which the vaporous diamines, optionally rarefied with an inert gas or with the vapors of an inert solvent, and phosgene are heated separately to temperatures of about 200 DEG C. to about 600 DEG C. and mixed and reacted in a tube reactor characterized in that a number n>=2 of nozzles directed parallel to the axis of the tube reactor are arranged in the tube reactor, the diamine-containing stream being fed into the tube reactor through the n nozzles and the phosgene stream being fed into the tube reactor through the remaining free space.

Description

technical field [0001] The invention relates to a process for the continuous preparation of (poly)isocyanates by phosgenation of corresponding (poly)amines in the gas phase with optimized educt mixing. technical background [0002] As used herein, (poly)isocyanates and (poly)amines refer to isocyanates, diisocyanates and polyisocyanates or monoamines, diamines and polyamines. [0003] It is known that in gas phase reactions, good mixing of educts is crucial to obtain high conversions and selectivities when reacting polyfunctional reactants. Optimal and practically spontaneous mixing of the educts is decisive for the economics of large-scale continuous processes in the following cases: [0004] a) the reaction of the educt is practically spontaneous (high reaction rate), [0005] b) one or more of the educts reacts with the product at a relatively high reaction rate, resulting in unwanted dimerized or oligomeric by-products, and / or [0006] c) dimerized or oligomeric by-pr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01F5/04B01J10/00C07C263/10C07C265/14
CPCB01F5/0453B01F5/0456B01J10/002C07C263/10B01F25/3132B01F25/31322C07C265/14
Inventor K·毕斯卡普P·克尔登尼克P·弗赫曼C·西克斯
Owner COVESTRO DEUTSCHLAND AG
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