Phenol is a very important organic chemical raw material, which is widely used in the production of various chemical products, such as plasticizers, antioxidants, curing agents, etc. Therefore, it is very important to master the manufacture technology of phenol. In this article, we will introduce the manufacture technology of phenol in detail.

The preparation of phenol is generally carried out by reacting benzene with propylene in the presence of catalysts. The reaction process can be divided into three steps: the first step is the reaction of benzene and propylene to form cumene; the second step is the oxidation of cumene to form cumene hydroperoxide; and the third step is the cleavage of cumene hydroperoxide to form phenol and acetone.

In the first step, benzene and propylene are reacted in the presence of an acid catalyst to form cumene. This reaction is carried out at a temperature of about 80 to 100 degrees Celsius and a pressure of about 10 to 30 kg/cm2. The catalyst used is usually aluminum chloride or sulfuric acid. The reaction product is cumene, which is separated from the reaction mixture by distillation.

In the second step, cumene is oxidized with air in the presence of an acid catalyst to form cumene hydroperoxide. This reaction is carried out at a temperature of about 70 to 90 degrees Celsius and a pressure of about 1 to 2 kg/cm2. The catalyst used is usually sulfuric acid or phosphoric acid. The reaction product is cumene hydroperoxide, which is separated from the reaction mixture by distillation.

In the third step, cumene hydroperoxide is cleaved in the presence of an acid catalyst to form phenol and acetone. This reaction is carried out at a temperature of about 100 to 130 degrees Celsius and a pressure of about 1 to 2 kg/cm2. The catalyst used is usually sulfuric acid or phosphoric acid. The reaction product is a mixture of phenol and acetone, which is separated from the reaction mixture by distillation.

Finally, the separation and purification of phenol and acetone are carried out by distillation. In order to obtain high-purity products, a series of distillation columns are usually used for separation and purification. The final product is phenol, which can be used for the production of various chemical products.

In summary, the preparation of phenol from benzene and propylene through the above three steps can obtain high-purity phenol. However, this process needs to use a large number of acid catalysts, which will cause serious corrosion of equipment and environmental pollution. Therefore, some new preparation methods are developed to replace this process. For example, the preparation method of phenol using biocatalysts has been gradually applied in industry.