Manufacturing method of o-propylphenol
o-propylphenol (OPP) is an important raw material for the production of chemicals, which is widely used in the fields of fungicides, antioxidants, fragrances, pesticides and so on. In this article, we will introduce the manufacturing method of o-propylphenol, including raw material preparation, reaction steps, post-treatment and so on.
I. Raw material preparation
The manufacture of o-propylphenol requires the preparation of the following raw materials: phenol, propylene. Among them, phenol is the main raw material and propylene is the alkylating agent.
II. Reaction steps
1. Alkylation reaction
Phenol and propylene are mixed at a molar ratio of 1:1.1-1.2, and the catalyst sulfuric acid or hydrofluoric acid is added to carry out the alkylation reaction at 70-90 °C. The reaction produces o-propylphenol and the by-product isopropylbenzene. The mechanism of alkylation reaction is that the phenolic hydroxyl group of phenol and propylene under the action of acid catalyst undergo electrophilic substitution reaction to produce o-propyl substituted phenol.
2. Neutralization and washing
After the reaction, the reaction solution is neutralized with alkali to a pH of 7-8 to remove the catalyst residue. The organic and aqueous phases were then separated by extraction with an organic solvent. The organic phase contains o-propylphenol and unreacted phenol, and the aqueous phase contains the by-product isopropylbenzene and inorganic salts.
3. Distillation Separation
The organic phase was distilled to first vaporize the unreacted phenol and then collect the o-propylphenol fraction. Since the boiling points of o-propylphenol and isopropylbenzene are quite different, they can be separated by distillation.
III. Post-treatment
1. Refining
The o-propylphenol obtained by distillation contains a small amount of isopropylbenzene and other impurities, which need to be refined. Commonly used refining methods include recrystallization, distillation and adsorption. Among them, recrystallization is the most commonly used method, which can increase the purity of o-propylphenol to more than 99%.
2. Packaging and storage
The o-propylphenol after refining needs to be packaged and stored. It is usually packaged in iron drums or plastic drums, sealed and stored away from direct sunlight and high temperature.
In short, the manufacturing method of o-propylphenol includes the steps of raw material preparation, alkylation reaction, neutralization and washing, distillation and separation and post-treatment. During the manufacturing process, attention needs to be paid to controlling the reaction conditions, ensuring product quality and environmental protection requirements. Meanwhile, the production process and equipment need to be optimized continuously in order to improve production efficiency and reduce costs.
