'Green' chemists swap oil for renewable alternatives
Look around you. What do you see? A computer screen, the print on this page, a pen, your shirt. Chances are there's petroleum in all of it. Petroleum-based substances are in everything from lipstick to laundry detergents, clothes to computers to chocolate bars - even fertilizers and pharmaceuticals. Petroleum for nonfuel use made up just over 5 percent of total oil consumption in the United States last year, according to the Department of Energy.Skip to next paragraph
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Five percent may not seem like a lot, but it's still 1 million barrels a day, more or less. That's enough to demand the attention of a new generation of industry and academic scientists who are working to find natural, nontoxic alternatives to petroleum for consumer products. They have dubbed their field "green chemistry."
"The way we've always dealt with environmental issues in the past is that we take products and processes, and if there's problems, then we try to clean it up afterwards," says Paul Anastas, a former EPA executive and director of the Green Chemistry Institute in Washington, D.C. "Green chemistry tries to do it from the design stage."
Those designs try to replace oil-derived ingredients with substitutes made from plant material such as corn, potatoes, biomass, or flower and vegetable oils.
"The industry wants drop-in technologies," says John Warner, director of America's only doctoral program in green chemistry at the University of Massachusetts at Lowell. "The product has to be something that in every way looks and feels the same - so that's the challenge."
The size of that challenge depends on the petroleum-related product to be duplicated.
In the case of paints, detergents, and personal care products like lotion and shampoo, the inspiration for green science has been around for a while. "Many years ago, paints were produced from vegetable and mineral resources," says Scott Egide, General Manager for AURO USA, which makes paints using linseed and flaxseed oils.
Oil-based chemicals began to appear in household cleaning products around World War II, says Martin Wolf, director of product and environmental technology for Seventh Generation, which makes petroleum-free detergents. "Animal fats and plant oils were the basis of soaps through the first part of the 20th century," he says. "Surfactants [soaps and detergents] made from petroleum later were just designed to mimic nature."
Substituting for the petroleum used in plastics, however, is a relatively new science. To make conventional plastics, oil must be broken down into constituent monomers, which are then reconstituted into polymer chains (plastics). Scientists have now mimicked this process with corn starches, creating a new polymer called polylactic acid (PLA).
While the idea of plant-based polymers goes all the way back to the 1930s and '40s, significant steps toward the development and production of PLA did not occur until the 1990s. "This is the product of literally decades of research," says Mr. Anastas.
Research continues to make natural plastic more durable and impermeable - necessary to make it competitive.
At Cornell University in Ithaca, N.Y., chemistry professor Geoffrey Coates and researchers from the school's Consortium on Green Polymers combine soybean-based proteins with natural fibers, like those found in pineapple, to make the plastics stronger.
In Professor Warner's lab in Lowell, Mass., researchers treat corn-based polymers with ultraviolet light. That twists and contorts the polymers, making them stronger and more durable.
The natural plastic can be intentionally broken down with the help of bacteria that turn the complex polymers back into plant material - which can then be reconstituted into natural plastic again.