Method for recycling arene in sulfonation process

Abstract

Provided is a method for recycling arene in the sulfonation process. Against an existing process of sulphonating arene by adopting sulfuric acid, arene which overflows along with air and non-condensable gas in the sulfonation process is sulphonated in an absorbing container to generate corresponding arene sulfonic acid and is dissolved in sulfonating agent absorbing sulfuric acid, the sulfuric acid containing the arene sulfonic acid serves as a sulfonating agent to be reused, and except that arene added in sulfonation is used for reaction, arene taken out along with the air is almost all recycled. During the sulfonation reaction, an evacuation pipe opening of a reaction kettle is connected into an arene absorption reaction kettle, a small amount of arene overflowing together with the air and the non-condensable gas enters the absorption reaction kettle, a small amount of arene is reacted by the sulfonating agent, and the non-condensable gas and the air come out of an absorbing system. Against an existing kettle type sulfonation device, the arene taken out along with the gas during sulfonation can be recycled by only needing a small amount of devices, the arene utilization rate is improved, tail gas is prevented from polluting the environment, the production cost is reduced, energy consumption is reduced, and the environment is protected.

Description

technical field [0001] The invention relates to a method for recovering aromatic hydrocarbons in the sulfonation process. Background technique [0002] Traditional benzene, toluene, xylene, ethylbenzene and other aromatics introduce a sulfonic acid group into the structure during sulfonation. Generally, the method of excess sulfuric acid or the solvent azeotropic method and gas phase method are used. These methods use sulfuric acid as the sulfonic acid group. The sulfonation process of the sulfonating agent, especially in the process of adding the above-mentioned benzene to increase the temperature and then adding sulfuric acid, the air in the reactor is gradually mixed by the steam of the benzene during the heating process of the benzene in the reactor. As the temperature rises, air and a small amount of benzene vapor overflow into the atmosphere from the reactor vent pipe due to difficulty in condensation. When sulfuric acid is added to react, the non-condensable gas gener...

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Problems solved by technology

[0002] Traditional benzene, toluene, xylene, ethylbenzene and other aromatics introduce a sulfonic acid group into the structure during sulfonation. Generally, the method of excess sulfuric acid or the solvent azeotropic method and gas phase method are used. These methods use sulfuric acid as the sulfonic acid group. The sulfonation process of the sulfonating agent, especially in the process of adding the above-mentioned benzene to increase the temperature and then adding sulfuric acid, the air in the reactor is gradually mixed by the steam of the benzene during the heating process of the benzene in the reactor. As the temperature rises, air and a small amount of benzene vapor overflow into the atmosphere from the reactor vent pipe due to difficulty in condensation. When sulfuric acid is added to react, the non-condensable gas generated in the reaction will overflow with benzene vapor. Due to the excessive amount of aromatics during the reaction, the aromatics need to be steamed out with negative pressure after the reaction reaches the end. When the equipment has leakage and non-condensable gases, the steam of aromatics and a small amount of air and non-condensable gases drawn into the equipment under negative pressure When mixed, it will affect the condensation of aromatics, resulting in the aromatics not being able to be condensed and entering the vacuum system

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