Method for producing m-dichlorobenzene with aromatic hydrocarbon chlorination waste as raw material

Abstract

The invention discloses a method for producing m-dichlorobenzene with aromatic hydrocarbon chlorination waste as a raw material. The method comprises the following steps: separating mixed dichlorobenzene stoste from the aromatic hydrocarbon chlorination waste, performing directional isomerization on the mixed dichlorobenzene stoste under catalysis of an HZSM 5 molecular sieve to translocate mixed dichlorobenzene into m-dichlorobenzene to obtain mixed dichlorobenzene of m-dichlorobenzene, p-dichlorobenzene and o-dichlorobenzene, selectively adsorbing p-dichlorobenzene by using an MFI hydrophobic amorphous silica zeolite molecular sieve as an adsorbent to obtain a mixed solution of m-dichlorobenzene and o-dichlorobenzene, and performing rectification separation to obtain m-dichlorobenzene with mass fraction higher than 99.5%. In the method disclosed by the invention, resource utilization is performed on the aromatic hydrocarbon chlorination waste to separate and extract the mixed dichlorobenzene stoste, p-dichlorobenzene whit higher content is separated by using two high-performance molecular sieves, and high-concentration m-dichlorobenzene is prepared by rectification technology; by adopting the production method disclosed by the invention, m-dichlorobenzene with mass fraction higher than 99.5% can be obtained, resources are saved and the environment is protected.

Description

technical field [0001] The invention relates to a method for producing m-dichlorobenzene, in particular to a method for producing m-dichlorobenzene by using aromatic hydrocarbon chlorination waste as a raw material. Background technique [0002] Now, m-dichlorobenzene is prepared by further chlorination of chlorobenzene to obtain p-dichlorobenzene, o-dichlorobenzene and m-dichlorobenzene. The general separation method adopts continuous distillation of mixed dichlorobenzene, para- and meta-dichlorobenzene are distilled from the top of the tower, p-dichlorobenzene is precipitated by freezing crystallization, and the mother liquor is rectified to obtain m-dichlorobenzene. o-dichlorobenzene, and then flash distilled o-dichlorobenzene in the flash tower. At present, mixed dichlorobenzene adopts the method of adsorption and separation, using molecular sieves as the adsorbent, and mixing dichlorobenzene in the gas phase into the adsorption tower, which can selectively adsorb p-dic...

AI Technical Summary

Problems solved by technology

[0003] The use of m-dichlorobenzene in industrial production is very wide, but the existing preparation methods of m-dichlorobenzene are relatively difficult, so the price of m-dichlorobenzene is relatively high. How to prepare high-content m-dichlorobenzene become an important subject

[0004] After directional chlorination of chlorobenzene, it is easy to form mixed dichlorobenzene, most of which are mixed dichlorobenzene and only contain a very small amount of m-dichlorobenzene. Therefore, a safe and reliable production method using mixed dichlorobenzene as raw material has been developed. The process of m-dichlorobenzene is one of the difficulties that many universities and research institutes are currently solving, and there has been no relevant report so far