'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.
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.
Purifying and breaking down used petroleum-based plastics is costly. Instead, plastic recycling usually consists of taking a high-end product and producing a low-end one. "I want to be able to take a laptop computer and make another laptop computer, not a speed bump," Warner says. "The dream with our technology is to be able, at low cost, to recover the polymer in its originally useful form."
Optimal use of energy is a paramount concern.
"You have to look at the energy balance," Professor Coates says. "It's not just 'Did the stuff come from nature?' It's 'Well, if it came from nature, is it worth it?' If it takes a lot of energy, you might be better off just converting your fossil fuels" into plastic.
Energy efficiency also keeps costs low. "Folks in industry like green chemistry, because it helps them meet profit goals and economic competitiveness goals," Anastas says. "Nonhazardous nontoxic chemicals are going to be cheaper to manufacture, and add value to the industry."
Large-scale production of biorenewable plastics is already under way.
NatureWorks LLC, a subsidiary of food and agriculture giant Cargill, sells corn-based plastic to manufacturers of plastic containers, cutlery, and packaging. Chemical company Dupont's biorenewable Sorona plastic can substitute for polyester and other synthetic fabrics.
And last year, Wal-Mart announced its intention to use only biorenewable materials for its plastic packaging.
"To replace a commodity material, you have to get those economies of scale," says Ann Tucker of NatureWorks. Her company has been able to lower the price of its biorenewable packaging plastic from more than $1 a pound to about 63 cents. While the price of the equivalent petroleum-based plastic packaging currently can cost as little as 40 cents per pound, NatureWork's pricing is extremely competitive, says Frank Esposito of PlasticsNews. That's because petroleum-based plastics bear the cost of rising oil prices. Large orders, like those anticipated from Wal-Mart, should lower the cost of biorenewable plastic still further, he says.
Support is also trickling in from the political sector, as various state governors (including those of Maine, just last week, and New York earlier this year) mandate the development and use of nontoxic chemicals.
Interest in Washington cuts across party lines.
"The first perception is always that green chemists are tree- hugging hippies, until they realize that this is hard core beakers-and-flasks chemistry," Anastas says.
The last significant challenge, perhaps, is acceptance by an increasingly oil-conscious America.
"Using petroleum in materials is not as bad as burning it," Anastas says. "But we never want to use a finite resource at a greater pace than we can replace it."
Clothing: Synthetic clothes are essentially plastic, which, like soda bottles and storage bins, are made from petroleum-based polymers. That includes such fibers as polyester and nylons, synthetic substitutes for shoe leather, hard plastic buttons, and plastic zippers. Most clothing dyes are oil-based as well.
Detergents: The surfactants that enable many modern soaps and detergents to break up greasy stains are derived from petrochemicals.
Chocolate: Many chocolates maintain their appetizing look with the help of paraffin, an oil-based wax also used in candles. The paraffin helps molded chocolate hold its shape, and makes it look shiny. Food-grade paraffin is harmless, but nondigestible.
Soda bottles and other plastics: The polymers that form the building blocks of plastics are made from reconstituted monomers, traditionally derived from petroleum and natural-gas liquids.