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Prepn process of carbamate and prepn process of isocyanate

A technology of carbamate and alkylaryl carbonate, which is applied in the field of carbamate preparation, can solve the problems of a large number of catalysts and the inability to increase the yield, and achieve the effect of high yield

Inactive Publication Date: 2003-07-30
MITSUI TAKEDA CHEM INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the disadvantage of this method is that a large amount of catalyst needs to be used and the yield cannot be improved

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0066] After replacing the air in a 200 mL four-neck glass flask with nitrogen, 45.6 g (0.30 mol) of methyl phenyl carbonate and 58.8 g of methanol were added to the flask, and then 11.6 g (0.10 mol) of 1 , 6-hexanediamine, wherein the four-neck glass flask was equipped with a reflux condenser, a thermometer, a nitrogen inlet fitting, a dropping funnel, and a stirrer. They were then allowed to react with each other at 50°C for 3 hours, and then a part of the reaction mixture was taken out as a sample, and the sample was subjected to potentiometric titration measurement with 1N hydrochloric acid. As a result, the conversion of hexamethylenediamine was 99.5% or higher. Also, from quantitative analysis of the reaction mixture using gas chromatography, it was found that 1,6-bis(methoxycarbonylamino)hexane was produced in a yield of 99.9%.

[0067] Thus, after transferring the reaction mixture into a 200 mL flask, the flask was heated under reduced pressure (0.67 kPa) so as to dis...

Embodiment 2

[0076] After replacing the air in a 200 mL four-necked glass flask with nitrogen, 76.1 g (0.30 mol) of crude methylphenyl carbonate (a reaction solution synthesized by transesterification of dimethyl carbonate and phenol, and simply Distilled, by weight, a mixture containing 60 parts by weight of methylphenyl carbonate, 26 parts by weight of phenol and 9 parts by weight of dimethyl carbonate, wherein the composition ratio was measured with a gas chromatograph) and 28.5 grams of methanol were added to the flask 11.6 g (0.10 mol) of 1,6-hexanediamine was then added dropwise with stirring at room temperature, wherein the four-neck glass flask was equipped with a reflux condenser, a thermometer, a nitrogen inlet connection, a dropping funnel and a blender. They were then allowed to react with each other at 50° C. for 4 hours, and then a part of the reaction mixture was taken out as a sample, and the sample was subjected to potentiometric titration measurement with 1N hydrochloric ...

Embodiment 3

[0078] After replacing the air in a 200 mL four-neck glass flask with nitrogen, 45.6 g (0.30 mol) of methyl phenyl carbonate and 63.3 g of methanol were added to the flask, and then 13.6 g (0.10 mol) of 1 , 3-bis(aminomethyl)benzene, wherein the four-neck glass flask was equipped with a reflux condenser, a thermometer, a nitrogen inlet fitting, a dropping funnel, and a stirrer. They were then allowed to react with each other at 60°C for 10 hours, and then a part of the reaction mixture was taken out as a sample, and the sample was subjected to potentiometric titration measurement with 1N hydrochloric acid. As a result, the conversion rate of 1,3-bis(aminomethyl)benzene was 99.0% or higher. Also, from quantitative analysis of the reaction mixture using gas chromatography, it was found that 1,3-bis(methoxycarbonylaminomethyl)benzene was produced in a yield of 99.7%.

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PUM

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Abstract

A method for producing carbamates that enables carbamates to be produced at low costs, with high selectivity and high yield, and in a simple manner, and a method for producing isocyanates that enables isocyanates industrially used to be produced by using the carbamates obtained by the carbamates producing method. Nonaromatic amine selected from the group consisting of aliphatic amine, alicyclic amine, and aralkyl amine is allowed to react with alkylaryl carbonate to thereby produce carbamates. Also, the carbamates thus obtained are thermally decomposed to thereby produce isocyanates. When carbamates are produced in this method, alkyl carbamates can be obtained with high selectivity and at high yield by using simple equipment. Also, when isocyanates are produced in this method, polyisocyanates used industrially as the raw material of polyurethane can be produced in a simple manner and with efficiency.

Description

technical field [0001] The present invention relates to a method for preparing carbamate, and a method for preparing isocyanate from carbamate prepared by the method for preparing carbamate. Background technique [0002] Alkyl carbamates are organic compounds that can be used as raw materials for medicines, agricultural chemicals, etc.; raw materials for various fine chemicals; reagents for alcohol analysis; and industrial raw materials for various purposes. [0003] Various methods are known for the preparation of alkyl carbamates, including (1) the reaction of isocyanates with alcohols, (2) the reaction of chloroformates with amines in the presence of a base, (3) the reaction of light A method of reacting gas with alcohol and amine, (4) a method of reacting urea with alcohol, (5) a method of reacting dimethyl carbonate with formamide, and (6) a method of reacting dialkyl carbonate with amine. [0004] In recent years, many studies have been carried out using alkyl carbama...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C263/04C07C265/04C07C265/14C07C271/12C07C271/20C07C271/22C07C271/24C07C319/20C07C323/43
CPCC07C271/12C07C271/22C07C271/20C07C2101/14C07C319/20C07C263/04C07C271/24C07C2601/14C07C323/43C07C265/04C07C265/14C07C269/04
Inventor 吉田力佐佐木祐明黑岩巧平田文明
Owner MITSUI TAKEDA CHEM INC
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