1. Almost all cyclohexanes are obtained by hydrogenation of pure benzene, and can also be produced by fractionation using a cyclohexane-rich fraction. There are many methods for hydrogenating benzene to cyclohexane, and the only difference lies in the difference in catalysts, operating conditions, reactor types, and heat removal methods. Usually divided into two kinds of liquid phase method and gas phase method, and the majority of the liquid phase method. The benzene hydrogenation method can be divided into: benzene liquid phase hydrogenation, benzene gas phase hydrogenation.

2, derived from the catalytic hydrogenation of benzene.

3, derived from crude oil separation.

4. Catalytic hydrogenation by phenylene cyclase. Recently, Ben Shen's research team at The Scripps Research Institute in the United States found that ChxG, a bacterial enzyme, is involved in catalyzing the production of cyclohexene by a benzene ring under ambient temperature and pressure conditions, and then another enzyme, ChxH, can bind the ring. Hexene is further reduced to cyclohexane. This study reports for the first time that the biological enzyme can control the catalytic hydrogenation of the benzene ring at room temperature and pressure in a controlled manner.