Water phase high pressure method for preparing N,N'-di (m-tolyl) urea

A technology of tolyl and m-toluidine, applied in the N field, can solve the problems of troublesome recovery, high synthesis cost, expensive amyl alcohol, etc., and achieve the effect of simple reaction

Inactive Publication Date: 2006-10-25
ZHEJIANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] There is only one Indian patent report (IN 161612) for the preparation of N,N'-bis(m-tolyl)urea by the condensation of m-toluidine and urea, in which pentanol is used as a solvent and react

Method used

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  • Water phase high pressure method for preparing N,N'-di (m-tolyl) urea

Examples

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Example Embodiment

[0016] Example 1

[0017] 1) After mixing m-toluidine and water, add sulfuric acid dropwise to form a salt reaction. After dropping, add urea and stir; the equivalent ratio of m-toluidine to sulfuric acid is 1:0.95, and the molar ratio of m-toluidine to urea is 1: 0.5, the salt-forming reaction temperature is 0℃;

[0018] 2) Put the above reaction liquid into the autoclave, the autoclave pressure is 2atm, keep it for 5 hours, release the pressure, discharge, centrifuge and wash with hot water to obtain the finished product N,N'-bis(m-tolyl)urea The molar yield is 90%, based on m-toluidine.

Example Embodiment

[0019] Example 2

[0020] 1) After mixing m-toluidine and water, add hydrochloric acid dropwise to form a salt reaction, add urea after dripping, and stir; the equivalent ratio of m-toluidine to hydrochloric acid is 1:1.05, and the molar ratio of m-toluidine to urea is 1: 1. The salt-forming reaction temperature is 80°C;

[0021] 2) Put the above reaction liquid into the autoclave, the autoclave pressure is 10atm, keep for 1 hour, then release the pressure, discharge, centrifuge, wash with hot water, get the finished product N,N'-bis(m-tolyl)urea The molar yield is 91%, calculated as m-toluidine.

Example Embodiment

[0022] Example 3

[0023] 1) After mixing m-toluidine and water, add phosphoric acid dropwise to form a salt reaction. After dropping, add urea and stir; the equivalent ratio of m-toluidine to phosphoric acid is 1:1, and the molar ratio of m-toluidine to urea is 1:1 0.5, the salt-forming reaction temperature is 0℃;

[0024] 2) Put the above reaction liquid into the high pressure reactor, the pressure of the high pressure reactor is 4atm, keep for 2 hours and then release the pressure, discharge, centrifuge, wash with hot water to obtain the finished product N,N'-bis(m-tolyl)urea The molar yield is 92%, calculated as m-toluidine.

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Abstract

This invention discloses n,n'-bi(inter cresyl) urea water phase high pressure preparation method. 1) m-toluidine is mixed with water, then mineral acid is added for salifying reaction, then urea is added and agitated, there equivalence ratio is 1:0.95-1.05, mol ratio of the m-toluidine and urea is 1:0.5-1, the salifying reaction temperature is 0-80 degree centigrade. 2) the reaction liquor above is added into high pressure kettle, pressure of the kettle reaches 2-10atm, and keeps 1-5 hours, then material is out, separated and washed. Comparing to existing preparation method, the material price is low and easy to get, reaction is simple, workshop operability is high, the whole yield and manufacture cost is low, so it is propitious to industrial manufacture. Computer by m-toluidine, the product mol yield can reach more than 90 percent of the theoretical value, if mother liquor is nest after reaction, the mol yield can reach more than 95 percent.

Description

technical field [0001] The invention relates to a preparation method of symmetrical diphenylurea, in particular to an aqueous phase high-pressure preparation method of N, N'-di(m-tolyl)urea. Background technique [0002] N,N'-bis(m-tolyl)urea is a rocket fuel stabilizer and a polymer additive. Another use of it is to produce 3-methyl-2,6-dichloroaniline after sulfonation, chlorination, and hydrolysis; this substituent aniline is an important pesticide intermediate, so the study of N, N'- The synthesis of di(m-tolyl)urea has industrial significance. [0003] There is only one Indian patent report (IN 161612) for the preparation of N,N'-bis(m-tolyl)urea by the condensation of m-toluidine and urea, in which pentanol is used as a solvent and reacted at 110°~145°C; The price is more expensive, and there is the trouble of recycling. Other N, N'-two (m-tolyl) urea synthetic methods relate to isocyanate etc., and synthetic cost is all very high, is all undesirable in industry. ...

Claims

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Application Information

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IPC IPC(8): C07C273/18C07C275/28
Inventor 李伟军林旭锋陈卫祥
Owner ZHEJIANG UNIV
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