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Method for producing 1,6-hexamethylene diisocyanate with hexa-methylene diamino-methyl formate liquid phase thermal cracking

A technology of methyl hexamethylene dicarbamate and hexamethylene diisocyanate is applied in the corresponding field of liquid-phase thermal cracking preparation, can solve the problems of clogging reactors and other equipment, reducing yield, low yield, etc. Less product, improved product purity and quality, and the effect of wide liquid path

Inactive Publication Date: 2008-06-11
LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The thermal cracking process is often accompanied by many side reactions, which not only reduces the yield, but also blocks the reactor and other equipment
In British Patent No. 1,247,451, toluene diisocyanate is prepared by thermal cracking of methyl toluene dicarbamate in the gas phase. The thermal cracking temperature is 400 ° C ~ 600 ° C, and its disadvantages are low yield and a large number of by-products

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] In a magnetically stirred round bottom flask of 2000 ml, add N-trimethyl-butyltetrafluoroborate ionic liquid (N 1114 BF 4 ) 500ml, under the condition of 200 ℃, 10mmHg and 200 rpm, add 200 grams of methyl hexamethylene dicarbamate, copper oxide / silicon oxide (supporting capacity is 5wt%) 20g, keep temperature and pressure reaction 1.5 After 1 hour, a mixed solution composed of hexamethylene-isocyanate-carbamate, hexamethylenedicarbamate and 1,6-hexanediisocyanate was obtained, and the chromatographic analysis of 1,6-hexanedi The yield of isocyanate is 88%, the separation yield is 82%, and the purity is 85%-90%. It can reach 98% after one rectification, and then it can be reused many times after adding raw material HDC.

Embodiment 2

[0022] Step is with embodiment 1, but with tetrabutylphosphonium tetrafluoroborate ionic liquid (P 444 BF 4 ) instead of N 1114 BF 4 , the mixed solution obtained, chromatographic analysis 1,6-hexamethylene diisocyanate yield 80%, the separation yield is 76% and the purity is 81% ~ 84%, can reach 96% after a rectification, after adding raw material HDC can Repeated use many times.

Embodiment 3

[0024] The steps are the same as in Example 1, but with nickel oxide-zirconia / silicon oxide (the loading of nickel oxide is 3wt%, and the loading of zirconia is 5wt%) instead of copper oxide / silicon oxide (the loading is 5wt%) , the dosage of the catalyst remains unchanged, and the others remain unchanged. The obtained mixed solution has a chromatographic analysis of 1,6-hexamethylene diisocyanate yield of 80%, a separation yield of 77% and a purity of 81% to 85%. After one The rectification can reach 97%, and it can be reused many times after adding the raw material HDC.

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PUM

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Abstract

The invention relates to a method for preparing corresponding 1, 6-hexadiisocyanate heated and cracked by hexamethylene aminomethyl formate liquid phase, which adopts ion liquid as reaction solvent and supported metal oxide as catalyst. The main character of the method is mild, clean and green in reaction condition, little in volatility, high in purity of the separated and obtained product and relatively less in by-product.

Description

technical field [0001] The invention relates to a method for preparing corresponding 1,6-hexamethylene diisocyanate by liquid-phase thermal cracking of methyl hexamethylene dicarbamate (HDC) in the presence of a suitable catalyst. Background technique [0002] As a class of important organic reaction intermediates, isocyanates are widely used in industry, agriculture, medicine and health. These compounds are widely used in the synthesis of polyisocyanates, polyurethanes, polyureas, polymer adhesives, insecticides, herbicides, etc. Among them, 1,6-hexamethylene diisocyanate (HDI) belongs to non-yellowing aliphatic diisocyanate, which is mainly used in automotive OEM coatings and repair paints, aircraft OEM paints and repair paints, anti-corrosion coatings, wooden furniture paints, wire enamelled paints, Train refinish paint, polyurethane adhesive with good light stability and rocket propellant, etc. [0003] At present, isocyanates are mainly prepared by reacting correspond...

Claims

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Application Information

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IPC IPC(8): C07C263/04C07C265/04
Inventor 邓友全郭晓光张庆华马昱博马祥元田雄王利国
Owner LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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