Benzene (C6H6) is a colorless, sweet and transparent liquid with a strong aromatic smell at room temperature. Benzene is flammable, toxic and a carcinogen. Benzene is a hydrocarbon and the simplest aromatic hydrocarbon. It is insoluble in water, soluble in organic solvents, and can also be used as organic solvents. Benzene is the basic raw material of petrochemical industry. The output and technical level of benzene production is one of the symbols of a country's petrochemical development level. Benzene has a ring system called benzene ring, which is the simplest aromatic ring The structure of benzene molecule after removing one hydrogen is called phenyl, which is expressed by pH, so benzene can also be expressed as PhH.