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Two-stage method and one-pot synthesis method for preparing aliphatic diisocyanate

A technology of diisocyanate and aliphatic diamine, applied in the field of aliphatic diisocyanate, can solve the problem of many side reactants

Inactive Publication Date: 2017-01-25
GREAT EASTERN RESIN INDAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0049] In the patent (US 6639101 B2) published by Sergio of Spain in 2003, it is proposed that hexamethylenediamine and dimethyl carbonate (DMC) are reacted to obtain methyl hexamethylene dicarbamate ( HDU) and then undergo high temperature cracking reaction to obtain HDI and CH 3 OH, while the by-product CH 3 OH can react with CO, O through Oxidativecarbonylation 2 The reaction produces dimethyl carbonate (DMC) and H2O, which can be recycled and reused. The advantage is that the reaction conditions of the process are mild, environmentally friendly, and the by-products can be recycled. However, the disadvantage is that there are many side reactants, and HDU is converted into HDI The chemical formula of the high temperature solution reaction is as follows:

Method used

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  • Two-stage method and one-pot synthesis method for preparing aliphatic diisocyanate
  • Two-stage method and one-pot synthesis method for preparing aliphatic diisocyanate
  • Two-stage method and one-pot synthesis method for preparing aliphatic diisocyanate

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0140] Synthesis of N,N'-Hexamethylenedicarbamate (HMBPC)

[0141] Hexamethylenediamine (HMDA, 6.0 g, 51.7 mmol), diphenyl carbonate (DPC, 22.67 g, 106 mmol) were added to a 500 ml three-necked flask containing 100 ml ethylene glycol diethyl ether. The mixture was stirred at room temperature with a magnetic stir bar. One neck of the bottle was equipped with a thermometer and filled with nitrogen, and the other neck was connected to a condenser filled with water, the upper end of which was connected to an oil seal. The reaction was carried out for 2 hours. The reaction was terminated when IR analysis indicated the absence of 4,4'-diaminodiphenylmethane and monocarbamate intermediates.

[0142] After the reaction was complete, the reaction mixture was continued to be stirred and the temperature was slowly lowered to room temperature. Precipitation of a white crystalline product was observed. Suction filtration is then applied to obtain the product. and dried in a vacuum ove...

example 2

[0148] Synthesis of N,N'-Hexamethylene Dicarbamate Using Different Reaction Solvents

[0149] Using phenol, toluene, methylcyclohexane, 1-bromopropane, ethylene glycol diethyl ether (1,2-diethoxyethane, EGDEE) etc. as the reaction solvent, the same procedure and analysis as in Example 1 were carried out. Synthetic conditions are summarized in Table 1. The results showed that ethylene glycol diethyl ether with low polarity was the best choice. The highest yield of 90.3% methyl hexamethylene dicarbamate (HDU) and the lowest 8.54% by-product urea can be obtained.

[0150] Table 1: The effect of different low polar solvents on the yield of HMBPC synthesis

[0151]

example 3

[0153] Synthesis of Methyl Hexamethylenedicarbamate (HMBPC) Using Different Amounts of Diphenyl Carbonate (DPC)

[0154] The same procedure and analysis as in Example 1 were performed except that the amount of diphenylcarbonate (DPC) was changed as shown in Table 2. As can be seen from Table 2, except when the amount of diphenylcarbonate (DPC) increases to 4 times of MDA molar number, can obtain the hexamethylene dicarbamic acid methyl ester that highest productive rate is 95% (HDU) urea with a minimum of 2.04% by-products.

[0155] Table 2: Effect of different DPC ratios on HMBPC yield in ethylene glycol diethyl ether (EGDEE)

[0156]

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PUM

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Abstract

The invention relates to a two-stage method and one-pot synthesis method for preparing aliphatic diisocyanate. The two-stage method or the one-pot synthesis method is adopted for preparing aliphatic diisocyanate through aliphatic diamine and diaryl carbonic ester. Also, aliphatic polyamine and diaryl carbonic ester also can be used for preparing polyisocyanates. According to the synthesis method provided by the invention, phosgene or highly toxic reagents and a chlorinated solvent are not adopted during the whole process.

Description

technical field [0001] The present invention relates to the preparation of aliphatic diisocyanates from aliphatic diamines and diaryl carbonates by a two-step or one-pot synthesis method, and the preparation of aliphatic polyisocyanates from aliphatic polyamines and diaryl carbonates. Different from the current industrial aliphatic diisocyanate phosgene process, the synthesis method of the present invention does not use phosgene or highly toxic reagents and chlorinated solvents. Background technique [0002] Isocyanates have a wide range of industrial applications, such as for the manufacture of polymers, especially organic diaryl isocyanates and polyaryl isocyanates for the production of polyurethane, polyurethane / urea, polyurea and related polymers. base isocyanate. [0003] Both aryl polyisocyanates and aliphatic polyisocyanates are useful in a variety of ways. Aryl diisocyanates, such as 2,4-toluene diisocyanate and 2,6-toluene diisocyanate (TDI) and 4,4'-diphenylmetha...

Claims

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Application Information

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IPC IPC(8): C07C265/14C07C263/04C07C271/52C07C271/58C07C269/04
Inventor 戴宪弘林维兴郭懿萱
Owner GREAT EASTERN RESIN INDAL
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