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Method for preparing (substituted) aromatic monoisocyanate from (substituted) aryl carbamate through thermal decomposition

A technology of aryl monoisocyanate and aryl carbamate, applied in carbamate preparation, organic chemistry, etc., can solve the problems of by-products, achieve mild reaction conditions, high conversion rate of raw materials, and high energy utilization rate Effect

Inactive Publication Date: 2012-04-04
CHENGDU ORGANIC CHEM CO LTD CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The use of solvents brings more energy consumption to the reaction process and product separation, and some solvents may also cause the formation of by-products

Method used

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  • Method for preparing (substituted) aromatic monoisocyanate from (substituted) aryl carbamate through thermal decomposition
  • Method for preparing (substituted) aromatic monoisocyanate from (substituted) aryl carbamate through thermal decomposition

Examples

Experimental program
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Effect test

Embodiment 1

[0020] 20.0 g of methyl phenylcarbamate was added into a 50 ml flask, and 0.1 g of catalyst ZnO was added at the same time, and the amount added was 0.5% of the mass of methyl phenylcarbamate. Under the condition of vacuum degree of 450mmHg, the reaction temperature was raised to 200°C, the condensed water temperature was 20°C, and the reaction was carried out for 120min. After the reaction, the fraction was treated with di-n-butylamine and analyzed by HPLC. The phenylisocyanate in the fraction was 13.26g , the yield was 84.1%.

Embodiment 2

[0022] In a 50ml flask, add 20.0g of methyl phenylcarbamate, while adding 0.2g of catalyst Co 2 o 3 , the addition amount is 1% of the quality of methyl phenylcarbamate. Under the condition of vacuum degree of 480mmHg, the reaction temperature was raised to 200°C, the condensed water temperature was 20°C, and the reaction was carried out for 100min. After the reaction, the fraction was treated with di-n-butylamine and analyzed by HPLC. The phenylisocyanate in the fraction was 13.81g , the yield was 87.6%.

Embodiment 3

[0024] Add 25.0 g of ethyl phenylcarbamate to a 50 ml flask, and at the same time add 0.2 g of catalyst neutral Al 2 o 3 , the addition amount is 0.8% of the mass of ethyl phenylcarbamate. Under the condition of vacuum degree of 540mmHg, the reaction temperature was raised to 220°C, the condensed water temperature was 40°C, and the reaction was carried out for 120min. At the end of the reaction, the fraction was treated with di-n-butylamine and analyzed by HPLC. The phenylisocyanate in the fraction was 14.09g , and the yield was 76.3%.

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Abstract

The invention relates to a method used for preparing (substituted) aromatic monoisocyanate from (substituted) aryl carbamate through thermal decomposition. During the whole thermal decomposition reaction process, no solvent is adopted, and generated (substituted) aromatic monoisocyanate and a by-product alcohol are separated by using a synchronic distillation method. The reaction is carried out under a reduced-pressure state with a vacuum degree of 180-700mmHg, a reaction temperature of 150-350 DEG C, a reaction time of 10-200min, and temperature of a cooling medium in a condenser clamp of 10-100 DEG C. the method provided by the invention is advantaged in low energy consumption, simple operation, high target product yield, and easy purification. The method has a good industrial application prospect.

Description

technical field [0001] The invention relates to an application for preparing (substituted) aryl monoisocyanate by thermal decomposition of (substituted) aryl carbamate. The method carries out liquid-phase thermal decomposition reaction under the condition of not using a solvent, and has the advantages of less energy consumption, simple operation, high yield of target product, easy purification and the like. Background technique [0002] As a class of important organic reaction intermediates, isocyanates are widely used in industry, agriculture, medicine and health. Such compounds are widely used in the synthesis of polyurethane materials, carbamate insecticides, herbicides, etc. (Jiawen. Application and Market Prospect of Isocyanates at Home and Abroad. Formaldehyde and Methanol, 2002, 3, 20-28.). [0003] There are many ways to synthesize isocyanate. The traditional production route of isocyanate is mainly phosgene method. This method adopts phosgenation reaction of organ...

Claims

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Application Information

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IPC IPC(8): C07C263/04C07C265/12
Inventor 王越张毅王庆印康涛姚洁王公应
Owner CHENGDU ORGANIC CHEM CO LTD CHINESE ACAD OF SCI
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