Rectifying separation method for chlorinated benzene production

Abstract

The invention discloses a rectifying separation method for chlorinated benzene production. The rectifying separation method comprises the following specific steps: feeding chlorine and excessive anhydrous benzene into a chlorinator filled with an iron ring catalyst; controlling the reaction temperature at the boiling point of benzene, namely, setting the temperature to 80-90 DEG C; starting a stirrer for constant-speed and constant-temperature stirring to generate chloride liquid; washing an obtained chlorinated benzene solution by a washing tower, neutralizing by a neutralizing kettle, extracting in an extraction kettle, and distilling by a two-stage rectifying tower to obtain a finished product. The rectifying separation method for the chlorinated benzene production disclosed by the invention is a universal method of the rectifying separation technology for the chlorinated benzene production at home, and has the following main advantages: high-temperature continuous chlorination is realized; the conversion selectivity of chlorinated benzene is high, the slender chlorination reactor does not tend to cause material mixing return, and a small amount of benzene dichloride is generated; a distillation process is adopted for separation, the technology is mature and reliable, useful matters are recycled, the synthesis cost is saved, the economic benefits are increased, and the method conforms to the scientific concept of greenness, environmental protection and zero pollution.

Description

technical field [0001] The invention relates to the technical field of pesticide synthesis, in particular to a rectification and separation method for the production of chlorinated benzene. Background technique [0002] Chlorinated benzene is a colorless, transparent, volatile liquid with a bitter almond smell. Melting point -45.6°C, boiling point 131.6°C, relative density 1.107 (20 / 4°C), refractive index 1.5248, flash point 23°C, autoignition point 637.78°C, flammable. The explosion limit in air is 1.83-9.23% (volume). Insoluble in water, easily soluble in alcohol, ether, benzene and chloroform, etc. Toxic, moderately toxic. The maximum allowable concentration in the workplace is 75×10-6; chlorinated benzene is an important basic organic synthesis raw material, used as dyes, medicines, pesticides, and organic synthesis intermediates. It is used in the manufacture of phenol, nitrochlorobenzene, dinitrochlorobenzene, aniline, nitrophenol and the pesticide DDT, etc. It is ...

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Problems solved by technology

[0003] In the traditional production of chlorinated benzene, the catalyst uses an iron ring. In the process of producing chlorinated benzene, the catalyst is not consumable, but the traditional production method catalyst accounts for a small proportion of the total material, and the relative proportion of benzene and chlorine Larger, the synthesis rate is low, the production capacity is not high, and the remaining raw materials of the reactants are difficult to handle, which not only increases the production cost, but also may cause pollution to the environment and increase the cost of environmental governance; at the same time, the traditional method uses batch fractional crystallization and centrifugal separation method to obtain chlorinated benzene, the energy consumption rate is high in the crystallization process, which increases the separation cost of chlorinated benzene; at the same time, the crystallization effect of the batch fractional crystallization method is not ideal, and it needs to be separated again in the follow-up rectification tower. Undoubtedly, higher requirements are put forward for subsequent rectification, which increases the cost of rectification

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