P-chloroaniline isocyanate preparation method

A technology of chloroaniline isocyanate and chlorophenyl isocyanate, which is applied in the field of preparation of p-chlorophenyl isocyanate, can solve the problems that solvents cannot be directly applied mechanically, and achieve good implementation value and social benefits, easy handling, and reasonable process conditions.

Inactive Publication Date: 2015-07-01
HUNAN LIJIE BIOCHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The yield of p-chlorophenylisocyanate in the above data is about 90%, and the ratio of bis(trichloromethyl)carbonate to the theoretical value is about 50%, and it is also found that the solvent cannot be directly applied after recovery, and it must be treated before it can be used.

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0041] Embodiment 1: the preparation method of p-chloroaniline isocyanate

[0042] 1) Synthesis of p-chloroaniline hydrochloride: Add 102.18g (0.8mol) of p-chloroaniline and 200g of toluene (equivalent to 1.96 times of p-chloroaniline) in a 500ml three-necked bottle, stir, raise the temperature to 50°C, and add 86g of Concentrated hydrochloric acid (concentration 36%, 0.84mol, equivalent to 1.05 times that of p-chloroaniline), about 40 minutes after the dropwise addition is completed, the temperature is raised to reflux for water separation, and after the water separation is completed, it is cooled to 40°C for about two hours, centrifugally filtered, Toluene is recovered, and the filter cake is directly cast into the next reaction;

[0043]2) Synthesis of p-chloroaniline isocyanate: Add the undried p-chloroaniline hydrochloride (about 130g, calculated as p-chloroaniline, the molar number is 0.8mol, the same below) and 95g of solid light ( 0.32mol (equivalent to 0.4 times of p...

Embodiment 2

[0044] Embodiment 2: the preparation method of p-chloroaniline isocyanate

[0045] 1) Synthesis of p-chloroaniline hydrochloride: Add 102.18g (0.8mol) of p-chloroaniline and 250g of recovered toluene (equivalent to 2.45 times of p-chloroaniline) in a 500ml three-necked bottle, stir, and drop 98g ( Concentration of 36%, 0.96mol, equivalent to 1.2 times of p-chloroaniline) concentrated hydrochloric acid, dropwise completed in about 55 minutes, heated up and refluxed for water separation, after water separation, about two hours. Cool to 40°C, centrifugally filter and recover toluene. The filter cake is directly cast into the next reaction;

[0046] 2) Synthesis of p-chlorophenyl isocyanate: Add the undried p-chloroaniline hydrochloride (about 130g in terms of p-chloroaniline, the molar number is 0.8mol) and 83g of solid light (0.28mol, 0.35 times of p-chloroaniline hydrochloride) and the ethyl acetate 200g (equivalent to 1.54 times of p-chloroaniline hydrochloride quality) of r...

Embodiment 3

[0047] Embodiment 3: the preparation method of p-chloroaniline isocyanate

[0048] 1) Synthesis of p-chloroaniline hydrochloride: synthesis of p-chloroaniline isocyanate: add p-chloroaniline 102.18g (0.8mol) and xylene 300g (equivalent to 2.94 times of p-chloroaniline) in a 500ml three-necked bottle, stir, and Add 90g of concentrated hydrochloric acid (concentration 36%, 0.88mol, equivalent to 1.1 times that of p-chloroaniline) dropwise at ℃, and the dropwise addition is completed in about 45 minutes. Toluene, about 145g. Then the temperature was lowered to 35°C, and the intermediate p-chloroaniline hydrochloride was filtered out by centrifugation. It took about 2 hours, and the filter cake was directly put into the next reaction.

[0049] 2) Synthesis of p-chlorophenyl isocyanate: add the undried p-chloroaniline hydrochloride (about 130g based on p-chloroaniline, its molar number is 0.8mol) into a 500ml three-necked bottle, and then add light to the reaction bottle 119g (0....

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Abstract

The invention relates to a p-chloroaniline isocyanate preparation method comprising the following steps: (1) p-chloroaniline hydrochloride is synthesized, wherein p-chloroaniline is adopted as a raw material and is subjected to a reaction with hydrochloric acid in an organic solvent, such that p-chloroaniline hydrochloride is synthesized; (2) p-chloroaniline isocyanate is synthesized, wherein p-chloroaniline hydrochloride and triphosgene are adopted as raw material, and p-chloroaniline isocyanate is synthesized in an organic solvent. The method provided by the invention has the advantages of advanced process route, reasonable process conditions, and high reaction yield. The materials used in production are not highly excessive; solvent dose in each step is low; and the solvent can be directly used without treatment. An intermediate is not needed to be dried, and can be directly used in the next step of reaction. Three-waste amount is low, and the waste is easy to treat. Therefore, the method has good implementation value and social benefit.

Description

technical field [0001] The invention relates to the field of basic chemical industry, in particular to a preparation method of p-chlorophenyl isocyanate. Background technique [0002] p-Chlorophenylisocyanate is an important intermediate of medicine, pesticide and polymer material. The synthesis of p-chlorophenyl isocyanate is mainly obtained by the reaction of p-chloroaniline and phosgene or solid phosgene. The yield of adopting the former can reach more than 90%, while the yield of adopting the latter is only about 85%, and solid phosgene is more expensive than phosgene. The use of phosgene synthesis, because phosgene is highly toxic, has a high safety risk, and the country has strict control over the production and use of phosgene. Therefore, major manufacturers at home and abroad use solid light to produce p-chlorophenyl isocyanate. [0003] Solid Light is also called solid phosgene, triphosgene, bis(trichloromethyl)carbonate, bis(trichloromethyl)carbonate, or BTC for ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C265/12C07C263/10
Inventor 陈弘朱新强胡汉忠
Owner HUNAN LIJIE BIOCHEM
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