Method for synthesizing p-phenylene diisocyanate

A technology for the synthesis of p-phenylene diisocyanate, which is applied in the preparation of isocyanic acid derivatives, chemical instruments and methods, and the preparation of organic compounds. It can solve problems such as harsh reaction conditions, complicated processes, and pollution, and achieve short reaction times. , The synthesis process is simple, the operation is simple and safe

Inactive Publication Date: 2005-10-26
杭州崇舜化学有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to solve the problems of complex process, harsh reaction conditions and serious pollution in the prior art, thereby providing a p-phenylene diisocyanate with simple and safe process, mild reaction conditions, high yield and no environmental pollution. resolve resolution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] In a 500ml three-necked flask, add 200gl of 2-dichloroethane, 0.8g of triethylamine and 25g of p-phenylenediamine, heat up and dissolve for later use.

[0027] In a 1000ml three-necked flask, add 400gl of 2-dichloroethane and 130g of bis(trichloromethyl)carbonate, stir to dissolve, and blow nitrogen into it. Then add the 1,2-dichloroethane solution of p-phenylenediamine, then raise the temperature to 110-120°C, and reflux at 0.15Mpa for 2 hours. The 1,2-dichloroethane was distilled off by nitrogen gas, filtered and washed to obtain 35.8 g of a solid product.

[0028] The melting point of the product is 96.5-98.0°C, the yield is 96.6%, and the isocyanate content is 52.0%.

Embodiment 2

[0030] In the 1000ml three-necked flask, add 400g of isoamyl acetate and 140g of bis(trichloromethyl)carbonate, and stir to dissolve. And into nitrogen. Then slowly add 225.8 g of the isoamyl acetate solution of p-phenylenediamine prepared in Example 1. Then raise the temperature to 125-138° C., and reflux at 0.15-0.24 MPa for 2 hours. The isoamyl acetate was distilled off by nitrogen gas, filtered and washed to obtain 36.4 g of a solid product.

[0031] The melting point of the product is 96.8-98.4°C, the yield is 98.2%, and the isocyanate content is 52.1%.

Embodiment 3

[0033] In a 500ml three-necked bottle, add 200g of chlorobenzene, 1.2g of triethylamine and 25g of p-phenylenediamine, heat up and dissolve for later use.

[0034] In a 1000ml three-necked flask, add 400g of chlorobenzene and 120g of bis(trichloromethyl)carbonate, stir to dissolve, and feed nitrogen. Then add the chlorobenzene solution of p-phenylenediamine, then raise the temperature to 120-128°C, and reflux at 0.12-0.20Mpa for 2.5 hours. Chlorobenzene was distilled off by nitrogen gas, filtered and washed to obtain 34.8 g of solid product.

[0035] The melting point of the product is 97.2-98.5°C, the yield is 93.9%, and the isocyanate content is 52.0%.

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Abstract

The present invention relates to a method for synthesizing p-phenylene diisocyanate. Said method includes the following steps: adding inert organic solution of di(trichloromethyl) carbonate into reaction flask, introducing nitrogen gas to make protection, under the condition of cooling slowly adding inert organic solution of p-phenylene diamine, making reaction for 2-4 hr, at 15-200 deg.C and 0-0.3 MPa, after the reaction is completed, removing solvent, filtering and washing so as to obtain solid product p-phenylene diisocyanate.

Description

technical field [0001] The invention belongs to a synthesis method of p-phenylene diisocyanate, in particular to a method for synthesizing p-phenylene diisocyanate in one step by reacting p-phenylene diamine with bis(trichloromethyl)carbonate. Background technique [0002] Polyurethane elastomer has been widely used in various fields of social life due to its high strength, good toughness, wear resistance, oil resistance and solvent resistance. The important structural factor affecting the performance of polyurethane is the diisocyanate in the hard segment. The better its rigidity, regularity, and symmetry, the greater the cohesive energy of the elastomer, the higher the phase separation, and the better the performance. P-phenylene diisocyanate is a typical symmetrical diisocyanate with molecular structure. It reacts with chain extenders such as diols or diamines to form dense polyurethane hard segments with high cohesive energy, so it has a good phase Separation, the perfo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C265/14
Inventor 聂天明俞介兵
Owner 杭州崇舜化学有限公司
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