Continuous nitration reaction device and method for benzene ring nitration

Abstract

The invention discloses a continuous nitration reaction device and method for benzene ring nitration. The device comprises a nitration raw material tank, a mixed acid preparation tank, a nitration feeding pump, a mixed acid feeding pump, a continuous nitration reactor and two coarse nitrate product separation tanks. With the continuous nitration reaction device and method for benzene of the invention adopted, the continuous nitration production is realized. The operation flexibility of the device is high, stable operation can be realized in a wider yield range, the production efficiency is high, the product quality is good, few byproducts are produced, the energy consumption and the raw material consumption are low, and the production process is safe and reliable.

Description

technical field [0001] The invention relates to a continuous nitration reaction device and method for nitration of benzene rings, and belongs to the field of nitration production technology. Background technique [0002] The reaction of introducing nitro groups into the aromatic ring is called nitration reaction. Nitrification is an electrophilic substitution. Nitrification reaction is a strong exothermic reaction. Its heat of reaction is 142KJ / mol. At the same time as the reaction, the sulfuric acid in the mixed acid is reacted to generate water Dilution also produces dilution heat (about 7% to 10% of reaction heat). If the reaction temperature continues to rise, side reactions will be caused, a large amount of nitric acid will be decomposed, and nitrophenol by-products will increase. These phenol by-products are the main cause of accidents in the production of nitrobenzene. At the same time, the nitrification reaction is a heterogeneous reaction, and the reaction occurs a...

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Problems solved by technology

[0005]1. When the kettle-type nitration reactor is used for the generation process of thermal nitration reaction, the heat transfer is mainly through the outer jacket of the kettle, and when the heat transfer of the jacket cannot meet the requirements It is necessary to install a heat transfer coil in the kettle to increase the heat transfer area. Adding a heat transfer coil will reduce the stirring diameter, weaken the mixing effect, and reduce the heat transfer coefficient. Therefore, the overall heat transfer effect of the kettle-type nitration reactor is not good.

[0006]2. When the tank-type nitration reactor is used for batch reaction, it generally adopts drop-feed feeding, and local overheating and uneven concentration distribution in the tank will occur at the feeding site, resulting in Product quality is not high and production capacity is limited

[0007]3. When the tank-type nitration reactor is used in the continuous nitration reaction process, multiple tanks need to be connected in series. Overnitration is not easy to control and the production process is complicated

But in traditional nitration process, the main shortcoming of above-mentioned technological process is: for controlling reaction temperature nitration time is long, along with the concentrated sulfuric acid in the carrying out mixed acid of nitration reaction is diluted, the nitrification ability weakens in the late stage of reaction, and by-product increases, and for nitration Equipment requires sufficient cooling area

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