News Release

Put a polymer in your tank

Peer-Reviewed Publication

American Chemical Society

New additive may boost mileage and power, cuts pollution

Washington D.C., Aug. 24 -- A gasoline additive that may be able to dramatically increase mileage and engine power with less pollution was described here today at the 220th national meeting of the American Chemical Society, the world's largest scientific society.

Now being tested in three U.S. states and other countries, the additive, polyisobutylene, is a polymer that works differently than the oxygenates now widely used as gasoline additives. It is vastly more effective as well, according to its developers.

Polyisobutylene can produce a 10 percent increase in horsepower, a 20 percent increase in mileage, and a 70 percent decrease in emissions of such environmental pollutants as carbon monoxide, unburned hydrocarbons and nitrogen oxides, according to Paul Waters, Ph.D., a professor emeritus at American University in Washington, D.C. He is also a scientific advisor to General Technology Applications, in Gainesville, Va., the company that developed the additive.

Gasoline is comprised of hydrocarbons - chains of hydrogen and carbon atoms - of different lengths. When gasoline and oxygen are combined and ignited in a car's engine, the molecules of hydrogen, carbon and oxygen rearrange themselves to form carbon dioxide and water. This reaction releases the energy that drives the engine.

Air, the engine's source of oxygen, does not contain enough oxygen to react fully with gasoline, so some hydrocarbons remain unburned. The energy thus lost could be used to power the engine more efficiently, according to Waters. Unburned hydrocarbons - some of which may be carcinogenic - also add to pollution, he says.

To increase the amount of oxygen available for combustion, oxygenates such as MTBE are added to gasoline. But recent evidence of groundwater contamination has raised concerns about the use of MTBE.

In contrast to MTBE, polyisobutylene changes the physical properties of gasoline rather than simply boosting oxygen content, says Waters.

When gasoline is sprayed into an engine's combustion chamber, smaller hydrocarbons separate immediately from larger ones, Waters explained. The smaller molecules burn first, and the larger hydrocarbons burn incompletely.

Adding just a small amount of polyisobutylene to a tank of gas reduces the separation of larger and smaller molecules, says GTA president Jerry Trippe. This allows the gasoline to burn more evenly, at a lower temperature. And because it also reduces emissions of nitrogen oxides, the process is more "environmentally friendly," according to Trippe. Moreover, because gasoline burns more evenly, fewer hydrocarbons are left unburned and more energy can be harvested, he claims.

The polymer can be used in all engines, from small two-cycle motors to large diesels, says Waters. Field tests are being conducted in California, Maryland and Wisconsin, as well as China, Japan and Ireland, says Trippe.

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The paper on this research, POLY 458, will be presented at 2:50 p.m. on Thursday, Aug. 24, at the J.W. Marriott Hotel, Capitol Salon E.

Paul Waters, Ph.D., is professor emeritus of chemistry at American University in Washington, D.C., and scientific advisor to General Technology Applications in Gainesville, Va.

Jerry Trippe is the president of General Technology Applications in Gainesville, Va.

A nonprofit organization with a membership of 161,000 chemists and chemical engineers, the American Chemical Society publishes scientific journals and databases, convenes major research conferences, and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.


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