Manufacturing method of isomeric xylene
I. INTRODUCTION
Isomeric xylene is an important raw material for the production of chemicals, which is widely used in the fields of plastics, rubber, fibers, solvents and fuels. With the continuous development of industrial technology, the demand for isomeric xylenes is increasing year by year. Therefore, it is of great significance to study the manufacturing method of isomeric xylenes to improve the production efficiency, reduce the cost and promote the industrial development. In this paper, the manufacturing method of isomeric xylene will be introduced in detail, including raw material selection, reaction principle, process flow, equipment selection and other aspects.
II. Raw material selection
The raw materials for the manufacture of isomeric xylene mainly include benzene, toluene and mixed carbon tetrachloride. Among them, benzene is a common chemical raw material with a wide range of sources and relatively low price; toluene is also a common chemical raw material, which can be used as a substitute for benzene; and mixed carbon tetrachloride is a common by-product in the petrochemical industry, which is rich in carbon tetrachloride components. According to different raw material sources and production cost considerations, different raw materials can be selected for the production of isomerized xylene.
III. Reaction Principle
The manufacturing method of isomeric xylene mainly adopts the principle of alkylation reaction, i.e., benzene and toluene or olefinic components of mixed carbon tetrahydrate undergo alkylation reaction to generate isomeric xylene. Alkylation reaction is an acid-base catalyzed reaction process, and commonly used catalysts include acid catalysts such as sulfuric acid, hydrofluoric acid, phosphoric acid and alkaline catalysts. Under the action of acid catalysts, benzene undergoes electrophilic substitution with olefins to produce alkylbenzene, while under the action of basic catalysts, benzene undergoes nucleophilic substitution with olefins to produce alkylbenzene as well. Different catalysts and reaction conditions will affect the selectivity and yield of the products.
IV.Process Flow
The manufacturing process flow of isomeric xylene mainly includes the steps of raw material pretreatment, alkylation reaction, product separation and refining. The specific process is as follows:
1. Raw material pretreatment: The raw material is pretreated with desulfurization and dehydration to ensure the smooth progress of the reaction. Alkylation: The pretreated feedstock is mixed with catalyst and alkylated at appropriate temperature and pressure to produce isomeric xylenes and other by-products. Separation of products: Isomeric xylenes and other by-products are separated by distillation, extraction and other separation methods.
4. Refining: Refine the separated isomeric xylenes to remove the impurities and get the product with higher purity.
V. Equipment Selection
In the manufacturing process of isomeric xylene, equipment such as reactor, separation tower, pumps, valves, etc., which are needed, should be selected according to the requirements of the process and the actual situation. Specifically, the reliability, corrosion resistance, sealing and other aspects of the performance of the equipment should be considered to ensure the normal operation of the equipment and the quality of the product.
VI.CONCLUSION
Isomerized xylene, as an important raw material for the production of chemicals, has an important significance in its manufacturing method for improving production efficiency, reducing costs and promoting industrial development. In the manufacturing process, suitable raw materials and catalysts should be selected according to the actual situation, and the process flow and equipment selection should be optimized in order to improve the quality and yield of the product. Meanwhile, safety management and environmental protection measures in the manufacturing process should also be strengthened to ensure the smooth progress and sustainable development of production.
