ETHYLENE: NUMBER ONE IN ORGANICS

More ethylene than any other organic chemical is manufactured in the United States -- over 30 billion pounds are made each year -- and its impact on the country's economy is enormous.

Ethylene can be prepared by thermally cracking hydrocarbons containing two or more carbons:

CH₃-CH₃ CH₂=CH₂ + H₂

For this reason, ethylene production facilities are often concentrated in parts of the country where natural gas is abundant. The small quantities of ethane, propane, and butane found along with methane in natural gas are used as the raw materials for ethylene production.

Today, ethylene is the starting material for the synthesis each year of almost 100 billion pounds of chemicals and polymers. The accompanying table gives formulas and end uses for the major chemicals synthesized from ethylene.

Major derivatives of ethylene and their uses

Ph = phenyl group

By far the largest fraction of the ethylene produced in the United States is used for the synthesis of plastics. Forty-five percent goes into the production of polyethylene, and another 25% goes into the synthesis of related plastics. These substances are, in turn, fabricated into materials for use in packaging, appliances, construction, toys, transportation, housewares, luggage, water-based paints, and more. A relatively minor but interesting use of ethylene is found in the fruit industry. Fruit, such as oranges and bananas, is picked green to prevent damage and spoiling while the fruit is being shipped to warehouses. Once it is in the warehouse, the fruit is exposed to ethylene, which serves as a natural chemical signal for the fruit to ripen. The fruit matures and is then delivered to local grocery stores.

Clearly, our dependence on ethylene is enormous, and given the nature of our industrialized society, it will continue to be enormous into the future.