Refining method of 3,4-dichlorobenzene isocyanate

A technology of dichlorophenyl isocyanate and refining method, which is applied to the preparation of isocyanic acid derivatives, purification/separation of isocyanic acid derivatives, chemical instruments and methods, etc., which can solve the problems of low precision, slow reaction speed, and reduced production Product yield and other issues to achieve the effect of reducing by-products, increasing reaction speed, and increasing yield

CN103739520AActive Publication Date: 2014-04-23ANHUI GUANGXIN AGROCHEM
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2014-04-23
Patent Text Reader

Abstract

The invention provides a refining method of 3,4-dichlorobenzene isocyanate. The process method comprises the following steps: firstly, preparing a 3,4-dichloroaniline methylbenzene solution, and then carrying out phosgene esterification reaction, and finally rectifying. According to the refining method, through continuous rectification, a product contains 99.5% of the 3,4 dichlorobenzene isocyanate, which is 1% higher than purity of a product achieved by common rectification; meanwhile, quality of the finished product is improved; content of methylbenzene after the continuous rectification is 99.5%; besides, the generation of side reactions is reduced when a phosgene reaction is performed, and the conversion rate of the methylbenzene is increased by 3%, therefore, when the 3,4 dichlorobenzene isocyanate reacts with other substances, generation of many byproducts is reduced, the reaction speed is improved, and the yield of the product is increased.
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Description

technical field

[0001] The invention relates to the field of 3,4 dichlorophenyl isocyanate production, in particular to a method for refining 3,4 dichlorophenyl isocyanate. Background technique

[0002] 3,4 dichlorophenylisocyanate is an important intermediate of medicine, pesticide and polymer material. The existing 3,4-dichlorophenylisocyanate generally has low precision after synthesis, so that many by-products will be produced when it reacts with other substances, and at the same time, the reaction speed will be slowed down, and the yield of the product will be reduced. Contents of the invention

[0003] Aiming at the above problems in the prior art, the present invention provides a method for refining 3,4-dichlorophenylisocyanate, which can make the turnover car more beautiful, cleaner and more sensitive.

[0004] The present invention is achieved through the following technical solutions:

[0005] A kind of 3,4 dichlorophenyl isocyanate refining method, described p...

Examples

Embodiment Construction

[0010] The invention provides a method for refining 3,4-dichlorobenzene isocyanate. The process includes the following steps: (1) First, prepare 3,4-dichloroaniline toluene solution: first add 3.58 parts of toluene solution to dissolve and dehydrate In the still, then add 0.87 parts of liquid aniline, stir evenly, transfer the evenly mixed mixture to the aniline toluene storage tank for later use.

[0011] (2) Then carry out the phosgene esterification reaction: add 1.62 parts of toluene into the cold light kettle, pass a quantitative 230 standard squares of phosgene into the cold light kettle, and then add 2.15 parts of 3,4 measured dropwise while passing the light -Dichloroaniline toluene solution, keep the pressure in the cold light kettle as negative pressure, control the temperature at 5-10 degrees, and stir for 15 minutes; transfer the product to the hot light kettle, slowly heat up until the sample is clear and transparent, and the specified value of phosgene toluene is ...