The two basic chemicals from petroleum and coal are ethylene and benzene.

Ethylene is a colourless, slightly odorous gas, which is one of the main products of petroleum cracking. In chemical production, ethylene has an extremely important position, and its output is one of the important symbols to measure the level of petrochemical development of a country. Ethylene is mainly used in the manufacture of plastics, synthetic fibres and synthetic rubber and other three synthetic materials, of which polyethylene is a thermoplastic resin produced by the polymerisation of ethylene, the output of plastics at the top; PVC is the second largest plastic species, which is made of vinyl chloride under the action of the initiator of the polymerisation of thermoplastic resins. In addition, ethylene can also be used for the production of ethanol, ethylene oxide, acetaldehyde, acetylene and other basic chemical raw materials, as well as pesticides, dyes, paints and many other fine chemical products.

Benzene is a colourless liquid with a special smell, which is a product of coal tar distillation or petroleum cracking. Benzene is mainly used as a raw material in chemical production, and can be made into a variety of benzene intermediates, such as aniline, phenol, etc. These intermediates can be further processed to produce dyes, pesticides, pharmaceuticals, explosives, rubber additives and other products. In addition, benzene can also be used as a solvent, extractant and fuel. However, it is worth noting that benzene is a toxic substance and long-term exposure to or inhalation of benzene vapour can be hazardous to human health, so strict safety measures need to be taken during its use.

As two basic chemical raw materials from petroleum and coal, ethylene and benzene play a pivotal role in chemical production. They are not only used in the manufacture of many basic chemical products, but also as raw materials for many fine chemical products.