Distillation for processing admixture of isomeric compound of diphenylmethane diisocyanate

A technology of diisocyanate and diphenylmethane, which is applied in the field of distillation treatment of isomer mixtures of diphenylmethane diisocyanate, can solve the problems of high operation cost of multi-step distillation method, and achieves low engineering cost and high device cost. and the effect of lower equipment expenses and lower heat

Active Publication Date: 2007-07-25
WANHUA CHEMICAL (NINGBO) CO LTD
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

Correspondingly, the operation cost of this

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  • Distillation for processing admixture of isomeric compound of diphenylmethane diisocyanate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] 2,2’-MDI

Embodiment 2

[0048] 2,2’-MDI

[0049] Example 1 is described: the separation column feed (stream 1) contains 0.18wt% of 2,2'-MDI, 6.59wt% of 2,4'-MDI, 93.16wt% of 4,4'-MDI and With a small amount of MCB and PHI, the 2,4'-MDIwt in stream 3 obtained after separation is more than 57%, and the 2,2'-MDIwt is less than 0.8%; 2,2'-MDI in stream 4 is not detected ,2,4'-MDIwt is less than 0.8%; stream 3 accounts for 6% of the feed volume, stream 4 accounts for 75% of the feed volume.

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Abstract

This invention relates to a method for distilling an isomer mixture of isocyanate. The method comprises: adding an isomer mixture of diphenylmethane diisocyanate into a separator, and distilling to obtain at least one product mixture, which comprises: 2,4'-MDI 50-60 wt.%, 4,4'-MDI 40-50 wt.%, 2,2'-MDI less than 1.5 wt.%, 2,4'-MDI less than 1 wt.%, and 4,4'-MDI greater than 99 wt.%. Compared with present distillation methods, the method has such advantages as saved distillation steps, reduced distillation column number, saved energy input, reduced isocyanate loss, and high 4,4'-MDI purity in the product mixture.

Description

1. Technical field [0001] The invention relates to a method for the distillation treatment of a mixture consisting of at least 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate , To prepare high-purity 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate containing a small amount of 2,2'-diphenylmethane diisocyanate and 4,4'-diisocyanate The phenylmethane diisocyanate mixture belongs to the technical field of isocyanate mixture treatment methods. 2. Background technology [0002] Aromatic isocyanates are important raw materials for preparing polyurethane materials. Among them, diphenylmethane diisocyanate and polymethylene polyphenyl isocyanate (MDI) have an absolute advantage in quantity. [0003] It is known that the corresponding diamine and polyamine of the diphenylmethane series can be prepared by the condensation reaction of aniline and formaldehyde, and then the diisocyanate and polyisocyanate (MDI...

Claims

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Application Information

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IPC IPC(8): C07C263/20C07C265/14
Inventor 杨光军杨万宏孙少文王世宇卫剑锋丁建生
Owner WANHUA CHEMICAL (NINGBO) CO LTD
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