Method for purifying 3,4-dichloronitrobenzene by utilizing continuous rectification under pressure reduction condition
A technology of dichloronitrobenzene and vacuum distillation, which is applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve problems such as unstable product qualification rate, high labor intensity, and impact on use, and achieve Save manpower, high degree of automation, stable production effect
Inactive Publication Date: 2019-01-18
HULUDAO TIANQI SHENGYE CHEM
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Problems solved by technology
However, batch distillation purification, whether it is the temperature of the tower top, the tower bottom, or the extraction of distillate, is variable. It mainly relies on manual operation, which is labor-intensive, unstable product qualification rate, high energy consumption, and low yield, which affects the use.
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[0012] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.
[0013] Provide a kind of method utilizing continuous rectification under reduced pressure to purify 3,4-dichloronitrobenzene, specifically:
[0014] The uncrystallized liquid released during the crystallization of 3,4-dichloronitrobenzene is continuously fed to the middle of the tower in a constant amount, and the feed does not need to be fed at the bubble point.
[0015] The parameters are: the pressure at the top of the tower is set to: -0.096Mpa~-0.097Mpa;
[0016] The feed composition is: 3,4-dichloronitrobenzene w...
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The invention relates to a technology for purifying 3,4-dichloronitrobenzene by adopting a continuous rectification method under a pressure reduction condition. The technology is a middle process forcrystal separation of 3,4-dichloronitrobenzene. According to the invention, the traditional batch fractionating method is abandoned and the continuous rectification method under the pressure reductioncondition is adopted, so that the defects of batch fractionating are overcome, the boiling point of system feed liquid is reduced, the decomposition of thermosensitive materials is reduced, the lossis reduced and the byproducts and the cost of post-processing are reduced. Due to the application of continuous rectification, automation level is increased, labor force is saved, instability of batchfractionating is reduced, energy consumption is reduced, equipment space is saved, production efficiency is increased and the technology is suitable for green industrial model.
Description
technical field [0001] The invention relates to the field of organic purification, in particular to a method for purifying 3,4-dichloronitrobenzene by continuous rectification under reduced pressure. Background technique [0002] 3,4-Dichloronitrobenzene is an intermediate for the preparation of azo dyes and chromophore AS-LB, as well as an intermediate for the manufacture of Liyanine, Finatin tincture and other medicines, and can also be used as a sensor for color film films. It is also an important raw material for the popular fungicide pyraclostrobin. Due to the limitation of output, boiling point and heat sensitivity, existing manufacturers produce 3,4-dichloronitrobenzene by crystallization method to purify 3,4-dichloronitrobenzene, while the uncrystallized part is purified by batch rectification method. However, batch rectification and purification, whether it is the temperature of the top of the column, the temperature of the column kettle, or the extraction of fract...
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IPC IPC(8): C07C201/16C07C205/12
CPCC07C201/16C07C205/12
Inventor 杨向党徐建昌尹连奇
Owner HULUDAO TIANQI SHENGYE CHEM