New materials made from soybean oil have excellent electronic properties and offer a low-carbon-footprint alternative to conventional plastics that are used in printed circuit boards.
Soybean oil can be mixed with conventional chemicals and converted into a strong, rigid plastic that could be used for high-speed, energy-efficient, electrical components, report researchers at the University of Delaware.
The greasy liquid could provide a cheap, abundant and renewable alternative to some of the plastics, resins and other petroleum-based materials now used to make the parts. The use of renewable ingredients in the new plastics may reduce greenhouse gas emissions and slow depletion of petroleum resources. In principle, other plant oils besides soy would work in the same way.
One target area for the new plastic is circuit boards – the internal units that relay signals in computers, radios and other electronics. They are often made from materials called epoxy resins, a family of plastics that frequently rely on bisphenol A (BPA) for stiffness. BPA is known to interact with the hormone system, most famously as an estrogen. The use of BPA has raised health concerns over harmful effects seen in animals at low doses. Human exposure is widespread and studies suggest the chemical may contribute to obesity, behavior problems and altered fertility and reproduction in people.
The researchers wanted to modify soybean oil so the individual oil molecules would create a chain and the other added ingredients would lend rigidity. They mathematically predicted that structures similar to benzene – six carbon atoms linked together in a planar ring – would give the desired properties. Bisphenol A, for example, contains two benzene rings in its structure.
The researchers manufactured the soybean-based material to validate the theory. A key ingredient needed was phthalic anhydride, which is best known as a raw material for phthalate plasticizers that are used in a variety of products and have been linked to health effects in animal studies. At levels of 10 – 20 percent, it improved both the mechanical and electrical properties of the soy-based plastics.
All of the soy-based materials had lower dielectric constants than epoxy resins – about 3.6 to 3.8 compared to 4.2 to 4.7. A low dielectric constant is important for high signal speed and low “crosstalk” of signals between lines in a circuit. The materials also have very low dissipation factors – a measure indicating that circuits could operate using less power.
Further research is needed to improve the environmental impacts of the soy plastics. It would be ideal to progress away from adding chemicals such as phthalic anhydride that have known health effects and moving toward a 100 percent biobased material. More benign sources of benzene ring structures also should be considered.
In a technology park just north of Boston, a new model for sustainable chemical research and development is unfolding. Created in 2007, the Warner Babcock Institute for Green Chemistry (WBI), led by organic chemist John C. Warner, is working with industry partners to redefine how scientists solve the technical challenges of developing safer chemical products and greener production processes.
Warner had been frustrated with the limited intellectual freedom of working in a traditional industry research position and with the funding restrictions of the academic environment. Then he hit on the idea of creating an academic-style laboratory but financing it like a contract R&D business, with clients paying experts to help solve their problems. Enter James Babcock, a Harvard-trained corporate lawyer who spent much of his career leading a global investment firm. Babcock, who is the chairman of WBI’s board of directors, provided the seed funding and, with mechanical engineer and entrepreneur William Kunzweiler, helped Warner get started.
In three years, Warner and his research team have become go-to scientists when manufacturing companies have an application they would like to improve but not the chemical expertise to accomplish the task. The institute is creating patentable intellectual property at a rapid pace: WBI has filed for some 140 patents for itself and its clients, and five products it has helped develop are ready to enter the marketplace. WBI is also cash positive from the income it receives from contracts with its clients, Warner says, although he declines to divulge the firm’s annual operating budget. These achievements have come during the worst U.S. economy in decades.
“It’s a successful model,” Warner beams. “I don’t want to paint it as being easy,” he says about the revenue-generating R&D at WBI. “We put in a lot of long hours here. We have a lot of hard-working people.”
WBI scientists are currently developing toxicology screening technologies such as a material that mimics eye tissue to substitute for live-animal testing, a nontoxic aqueous solution for stripping photoresist from silicon wafers, a less energy-intensive process for making solar panels, and alternatives to the controversial chemical bisphenol A used in plastic bottles and cash-register receipt paper. Warner, who serves as WBI’s president and chief technology officer, notes that each of these projects has its roots in green chemistry.
In 1996, Warner and organic chemist Paul T. Anastas literally wrote the book on green chemistry: “Green Chemistry: Theory and Practice.” Anastas is now the assistant administrator in charge of the Environmental Protection Agency’s Office of Research & Development (C&EN, April 26, page 32).
In their “molecular-level how-to guide,” Warner and Anastas established the 12 Principles of Green Chemistry, a framework of concepts such as using less hazardous reagents and solvents, simplifying reactions and making them more energy efficient, using renewable feedstocks, and designing products that can be easily recycled or that break down into innocuous substances in the environment.
“Green chemistry is the mechanics of doing sustainable chemistry,” Warner observes. “By focusing on green chemistry, it puts us in a different innovative space. It is a science that presents industries with an incredible opportunity for continuous growth and competitive advantage.”
Warner started his career in 1988 as a research chemist at Polaroid, working on colorless-to-color printing technologies. Yearning to make a bigger difference with green chemistry, he left his lucrative job in 1996 to take an academic position at the University of Massachusetts, Boston, where he established the first doctoral program in green chemistry. In 2004, Warner moved to UMass Lowell, where he founded the Center for Green Chemistry. But Warner still felt the pace of innovation—putting green chemistry into practice—was moving too slowly, prompting him to take a leap of faith and start WBI.
When WBI opened its doors three years ago, it had a staff of 10, Warner notes. Because of its financial success and ability to attract a steady stream of clients—even without advertising—the institute now has about 40 employees, including chemists, biologists, toxicologists, engineers, and physicists.
A walk through WBI’s 42,000-sq-ft facility reveals standard lab benches, fume hoods, and analytical instrumentation, plus an array of specialized lab equipment and instruments for developing, analyzing, and testing films, coatings, and surfaces. Much of Warner’s chemistry, he explains, is based on the concept of “noncovalent derivatization,” which employs hydrogen bonding and π-stacking interactions of aromatic ring compounds.
“Normally, when chemists want to modify a molecule, they use reaction chemistry to change or add functional groups or perhaps form a polymer—changes that often involve multiple steps, hazardous reagents, and create waste,” Warner says. “Sometimes, there’s no need to create new molecules, but instead to intentionally combine an existing molecule with other substances in appropriate ratios and use the noncovalent interactions to obtain the desired effect.” The properties of materials can typically be controlled by pH, temperature, light, or humidity, he notes, and these materials typically have reduced toxicological and environmental impact.
“It’s chemistry controlled by entropy rather than by enthalpy,” Warner says.
One of WBI’s successes is significantly improving the oral availability of a promising Parkinson’s disease drug that was impractical to administer to patients. The drug is now in clinical trials.
“Because the dose can be much smaller, less drug has to be manufactured, and that significantly reduces chemical waste, which is very high in pharmaceutical production,” Warner explains. “But more important, with the lower dose, the body excretes less drug or drug metabolites into the environment. We accomplished this by looking at the morphology of the molecule and taking advantage of noncovalent interactions to control its solubility and release kinetics.”
WBI scientists have also created a green hair dye—not one that dyes hair green, but rather one that restores natural hair color while avoiding highly toxic chemicals. For example, Warner points to one popular commercial hair product for men that uses lead tetraacetate, which is toxic and has been banned in some countries.
“We really wanted to work on something to replace that product,” Warner says. “We looked at the structure of human hair pigment and came up with a greener technology to mimic it.”
Not only is Warner one of the inventors of the dye, which is still being tested, he is also a user. He volunteered to test the dye on his own graying hair, restoring the chestnut color and his youthful look from a decade ago.
“We are kind of working all over the place,” Warner notes. “My philosophy is that a molecule doesn’t know what kind of application it’s in—it could care less if it’s in a pharmaceutical, a cosmetic, or a coating material. We rely on our partners to know the application they want. We focus on developing the chemistry to make it happen. It’s a true collaboration.”
Essentially all of the research conducted at WBI goes unpublished. Warner says it’s not his goal to build up an endless publishing record. And the institute shuns public recognition from the companies it partners with, he adds. Warner doesn’t name names when it comes to the institute’s clients either. But they are recognizable, household names, he says.
Warner says he just wants to develop and promote green chemistry as a model way to do science. For that reason, he insists that contracts with clients include an “antiburial clause” to ensure that the intellectual property doesn’t collect dust on a shelf—if it does, the rights revert back to WBI so the invention can be put to use.
Aside from the science, the culture of the Warner Babcock Institute is driven home by the amenities of its research facilities: a full kitchen, workout room, yoga studio, game room, and a replica of Grandma Warner’s living room with a television and sofas. “Our goal is to provide our staff with an environment that enables scientific achievement through interactions of a diverse and multidisciplinary team,” Warner says. “We do everything we can to foster creativity and hard work with laid-back intensity.”
It’s a different approach. Given WBI’s success thus far, Warner and his team seem to have gotten it right.
Romanelli, GP, EG Virla, PR Duchowicz, AL Gaddi, DM Ruiz, DO Bennardi, E del Valle Ortiz and JC Autino. 2010. Sustainable synthesis of flavonoid derivatives, QSAR study and insecticidal activity against the fall armyworm, Spodoptera frugiperda (Lep.: Noctuidae).Journal of Agricultural and Food Chemistry 58:6290-6295.
No solvent and no corrosive acids. That’s part of the recipe for a new, less polluting method of making chemicals that kill an important crop pest. Taking their inspiration from natural plant chemicals called flavones, the authors of the study developed a way to make, compare, and test the insecticides, and used the information to create a predictive computer model.
The cleaner synthesis was used to control fall armyworms, one of the main threats to corn crops in many parts of the world. The new method avoids toxic solvents and strong mineral acids that were needed in earlier processes.
Instead, it relies on a metal catalyst that works at low levels: one catalyst molecule per 200 molecules of starting material. The catalyst could be easily recovered at the end of the chemical reaction and recycled several times, reducing waste.
Flavones protect plants against a variety of bacteria and insects. Some flavones also show beneficial effects in humans as antioxidants, anti-inflammatory agents, antimicrobials and anticancer agents.
The researchers made synthetic flavones using the greener technique and found that the chemicals were effective against the armyworm larvae. Based on these results, the researchers then created a computer model to predict which natural flavones might be worth testing as pesticides. They analyzed the structures of more than a dozen plant flavones and found two with characteristics in common with the chemicals that worked against armyworms.
One of the natural flavones, luteolin, occurs naturally in the human diet, in carrots, peppers, celery, and some spices. The other, apigenin, is common in citrus fruit, tea, and a variety of vegetables. Both chemicals are often cited for their therapeutic effects in humans.
The next step is for scientists to test whether these two natural flavones do indeed kill insects, as predicted by the model. While the natural flavones would probably have minimal environmental impacts if applied as pesticides, the synthetic flavones reported in the study were not tested for environmental persistence or toxicity to organisms besides armyworms. Those experiments would confirm whether the greener preparation leads to greener pesticides.
Xiang, H, C Sun, D Jiang, Q Zhang, C Dong and L Liu. 2010. Flame retardation and thermal degradation of intumescent flame-retarded polypropylene composites containing spirophosphoryldicyandiamide and ammonium polyphosphate.Journal of Vinyl and Additive Technology 16:161-169.
Polypropylene plastic (PP) was less flammable yet remained strong when mixed with two chemicals considered safer than those currently used as flame retardants, report Chinese researchers. The chemical blend achieved the highest flame retardancy rating in standardized tests without significantly impacting the strength of the plastic.
PP, which is coded as number 5 in plastic recycling, is used in numerous consumer products including carpets and thermal underwear.
The new flame retardant is a step forward in finding an alternative to traditional systems that are based on halogen-containing chemicals and antimony trioxide, say the researchers who developed the chemical blend. Alternatives are desired to prevent toxic, corrosive gases from forming during fires. Also, several classes of halogen-based flame retardants – like polybrominated diphenyl ethers – are raising concerns about persistence in the environment, toxicity and accumulation in animals and humans.
One of the additives, ammonium polyphosphate, is well known as a flame retardant, but by itself it cannot protect PP. The scientists invented a second additive – spirophosphoryldicyandiamide (SPDC) – that created synergy in the polymer blend. In the presence of a flame, the two additives formed a protective char layer that shielded the inside of the plastic from heat and prevented flaming drips. The combination also reduced heat, carbon monoxide gas and smoke.
Cost might limit the practicality of the new system. However, perfomance was adequate when the more expensive SPDC chemical was limited to just 25 percent of the flame retardant combination. The total amount of additives in the experiments was 30 percent of the plastic by weight.
The researchers showed that the new additives are safer compared to halogenated chemicals during fires. But, the overall green benefits of their technology are still not calculated. Further testing of the blends’ leaching, persistence and toxicity is necessary. Also, several highly toxic starting materials – like dicyandiamide and phosphorus oxychloride – are needed to make SPDC. These would be dangerous to workers and surrounding communities in the event of an accident.
In reviewing a proposed bill to ban BPA from food and beverage containers, a San Francisco Chronicle article presents a one-sided view of available alternatives.
A San Francisco Chronicle article describes efforts by U.S. Representative Dianne Feinstein to pass a bill banning bisphenol A (BPA) from food and beverage containers. Unfortunately, the reporter relies on information provided by industry officials to explain the availability of BPA-free alternatives. This one-sided approach misinforms readers.
Reporter Carolyn Lochhead states that “With no viable alternative for can liners, an immediate ban would be equivalent to banning canned foods.” An industry spokesman adds that “banning [BPA] would make food less safe because there is no viable alternative to line cans and jars.”
These statements stretch the truth. There are, in fact, food cans on the market without BPA in their epoxy linings. Some BPA-free cans are made with a vegetable-based lining that was used by the canning industry before the switch to BPA-based resins. These have been used for more than a decade.
Lochhead interviewed only a few sources for her story: Representative Feinstein; a U.S. Food and Drug Administration representative; and the director of the American Chemistry Council, an industry lobbying group. The important voice that is missing is an independent scientist. A scientist who works on BPA could have pointed out the alternative cans that exist and provided better accuracy in reporting the effects of BPA on animals and humans.
Human exposure to BPA is widespread through food can linings, polycarbonate plastics, some thermal papers and dental sealants, among other sources. A 2008 study by the US CDC showed that almost everyone has this chemical in their bodies. Reducing or eliminating BPA in consumer products can have a significant impact on human exposures. A 2003 study found that BPA levels in urine collected from Japanese college students in 1999 dropped compared to levels measured from similar students in 1992. During this period of time, the authors report that some can linings were changed from a BPA-based resin to a lining that eliminated or reduced the use of BPA.
BPA has been linked to numerous adverse health effects in exposed animals, including malformations of the male and female reproductive tract, changes in the development of the brain, alterations in the immune system, development of prostate and mammary cancers, and changes in behavior, among others. BPA studies in humans, while limited, also suggest that this chemical could have adverse health effects.
Certain classes of organic molecules can be instrumental in both capturing carbon dioxide from the air and incorporating it into new plastic materials, which could lessen the need for raw petroleum.
Chemists have made progress in finding environmentally friendly ways to capture and reuse carbon dioxide (CO2). Specifically, significant new advances have been made in the ability to absorb CO2 from the atmosphere and incorporate it into new raw materials – including benign alternatives to BPA-based plastics.
Certain classes of organic molecules have been discovered to be instrumental in capturing carbon dioxide from the air and incorporating it into new plastic materials. This process eliminates petroleum as an input, and generates more benign materials in the process.
In this and several other recent articles, researchers report how a class of chemicals – called “ionic liquids” – can efficiently capture and incorporate CO2 into chemicals, which can then be turned into a plastic. Such plastics can contain about 40 percent by weight of incorporated CO2.
CO2 is an excellent chemical building block; it is renewable, abundant and considered environmentally friendly. Plants efficiently convert CO2 into food through photosynthesis. Scientists, however, have long struggled to reproduce this process at an industrial scale. Before recent advances, the methods that existed were very inefficient, rendering them economically unviable.
Two research groups may have stumbled on a much more efficient method. Using chemicals called imidazoliums and N-heterocyclic carbenes (NHCs), researchers in Singapore report they were able to couple CO2 with molecules called “epoxides” to form polycarbonates – plastics used in everything from water bottles to compact disks. Importantly, in addition to finding a new use for carbon dioxide, these polycarbonates do not contain bisphenol A. It turns out that while virtually all commercial polycarbonate plastics today are made using bisphenol A as the basic building block, there are alternatives, as demonstrated by this research.
The imidazolium salts are stable chemicals that can repeatedly “grab” CO2 molecules and hand them over to be incorporated into bigger molecules. This makes them valuable in processes that convert CO2 to other chemical products as well. In addition, they are more benign and the reactions less severe than the metals typically used.
In sum, this research demonstrates two significant advances, first in demonstrably moving forward the capacity to harness and use CO2 in industrial applications, second in its successful application in developing a benign alternative to a problematic chemical.
6 May What can we do with carbon dioxide? Scientists are trying to find ways to convert the plentiful greenhouse gas into fuels and other value-added products, some saying that target areas should focus on using CO2 to replace large-volume starting materials derived from petroleum and natural gas.Chemical & Engineering News.
Green Chemistry: Scientists Devise New “Benign by Design” Drugs, Paints, Pesticides and More
Chemists are usually asked to invent a solution, but without considering hazardous by-products. Green chemists now are doing both with success, but will it take regulations to enforce the approach broadly?
Back in the days when better living through chemistry was a promise, not a bitter irony, nylon stockings replaced silk, refrigerators edged out iceboxes, and Americans became increasingly dependent on man-made materials. Today nearly everything we touch—clothing, furniture, carpeting, cabinets, lightbulbs, paper, toothpaste, baby teethers, iPhones, you name it—is synthetic. The harmful side effects of industrialization—smoggy air, Superfund sites, mercury-tainted fish, and on and on—have often seemed a necessary trade-off.
But in the early 1990s a small group of scientists began to think differently. Why, they asked, do we rely on hazardous substances for so many manufacturing processes? After all, chemical reactions happen continuously in nature, thousands of them within our own bodies, without any nasty by-products. Maybe, these scientists concluded, the problem was that chemists are not trained to think about the impacts of their inventions. Perhaps chemistry was toxic simply because no one had tried to make it otherwise. They called this new philosophy “green chemistry.”
Green chemists use all the tools and training of traditional chemistry, but instead of ending up with toxins that must be treated and contained after the fact, they aim to create industrial processes that avert hazard problems altogether. The catch phrase is “benign by design”.
Progress without pollution may sound utterly unrealistic, but businesses are putting green chemistry into practice. Buying, storing, and disposing of hazardous chemicals is expensive, so using safer alternatives makes sense. Big corporations—Monsanto, Dow, Merck, Pfizer, DuPont—along with scrappy start-ups are already applying green chemistry techniques. There have been hundreds of innovations, from safer latex paints, household cleaning products and Saran Wrap to textiles made from cornstarch, and pesticides that work selectively, by disrupting the life cycles of troublesome insects. Investigators have also developed cleaner ways of decaffeinating coffee, dry-cleaning clothes, making Styrofoam egg cartons, and producing drugs like Advil, Zoloft and Lipitor.
Over the past 15 years, green chemistry inventions have reduced hazardous chemical use by more than 500 million kilograms. Which sounds great, until you consider that every day the U.S. produces or imports about 33.5 billion kilograms of chemicals. The annals of green chemistry are full of crazy, fascinating stories, like a plan to turn the unmarketable potatoes from Maine’s annual harvest into biodegradable plastics. Still, a decade after the phrase was coined, green chemistry patents made up less than 1 percent of patents in chemical-heavy industries.
What will it take for green chemistry to be more than the proverbial drop in the bucket, a bucket full of toxic sludge? Some experts believe that the answer is government intervention—not only laws that ban harmful chemicals, but laws that simply require chemical manufacturers to reveal safety data and let the market do the rest. “Right now, companies that make chairs or cars or lipstick don’t know which of the chemicals they incorporate into their products are safe,” says Michael Wilson, an environmental health scientist at the University of California, Berkeley. “Once that information becomes available, there will be a demand for less toxic ingredients.”
That question—to regulate or not to regulate—has split the community of green chemistry advocates. Some oppose making green chemistry mandatory: its principles are so sensible and cost-effective, they believe, that industry will implement them voluntarily. Others, such as Wilson, disagree. The key, he asserts, is “fundamental chemicals policy reform in the U.S.”
Now is a critical time: After decades of inaction, the U.S. government is finally examining more aggressively the health effects of common chemicals. The ambitious Safe Chemicals Act, unveiled last month in the U.S. Senate, would require all industrial chemicals to be proved safe, creating a strong incentive for the development of less harmful alternatives. And the President’s Cancer Panel released a landmark report earlier this month decrying the “grievous harm” done by cancer-causing chemicals such as bisphenol A in food and household products.
The stakes are high, higher than most people realize. The companies that make the 80,000 chemicals that circulate in our world are rarely requiredto do safety testing, and government agencies are relatively powerless. “This is pretty shocking, since most people assume that someone is checking what’s on the market. The ingredients in my shampoo? The ingredients in my child’s toys? No one’s on the job? And that’s the answer: By and large, no one’s on the job,” says Daryl Ditz, a senior policy adviser at the Center for International Environmental Law (CIEL) in Washington, D.C.
“If we’re going to continue on as an industrial society that’s based on synthetic chemicals, we’ve got to figure out a way around this stuff. There’s really no question about that,” says Jody Roberts, an environmental policy expert at the Chemical Heritage Foundation in Darby, Pa. “I think that’s where the frustration for some people is, that it needs to be happening faster.”
Green chemistry’s beginnings
Perhaps no one has gambled more on green chemistry than John Warner. Along with Paul Anastas, the co-founder of green chemistry and now the assistant administrator for the EPA’s Office of Research and Development, he helped create a federal awards program that brought the field into the mainstream. And with Anastas he literally wrote the book: Green Chemistry: Theory and Practice, what Warner calls “a how-to guide at the molecular level.” In it they establish 12 guiding principles for chemists, concepts like preventing waste by incorporating as much of the materials used into the final product, and choosing the least complicated reaction.
A dozen years ago Warner, 47, left a lucrative job at Polaroid to found the nation’s first doctoral program in green chemistry. In 2007, tired of lecturing that green chemistry is the wave of the future, he decided to prove it, founding a start-up, the Warner Babcock Institute for Green Chemistry, in Wilmington, Mass. His firm, staffed by two dozen bright young scientists, is an ingenuity factory. They are working on all kinds of projects: a less energy-intensive way to make solar panels, a cheap water purification device for the developing world, and materials that mimic eye and liver tissue to substitute for live animals in toxicity testing.
Some of the work is basic research. One of Warner’s core technologies is based on thymine, one of the four bases of DNA. When exposed to light, thymine molecules attach to one another; because this reaction can be harmful (think: skin cancer) many organisms possess enzymes tasked with breaking those bonds. If you put thymine in a substance and expose it to light, it hardens; apply enzymes and it softens again. No toxicity, many potential applications. A scientist in Warner’s lab is using this technology to perm hair without caustic chemicals—simply by coating curled strands with a thymine-based polymer then shining light to freeze them in place. The technology could also act as a masking technique during the manufacture of printed circuit boards. Or imagine truly recyclable plastics that could be returned to their raw materials after the user throws them away.
That practical vision is a product of Warner’s upbringing. He grew up in Quincy, Mass., a tough working-class town south of Boston, and he hasn’t shed the local dialect. “I am a chemist. I make molecules,” he says, as if he could just as easily be building a house or an engine. In his plaid shirt and scuffed sneakers, he comes across more like the kind of guy you might bring your car to when it makes a funny rattle.Warner’s uncles, Sicilian immigrants, worked in construction and stone cutting, and he sees no disconnect between his blue-collar beginnings and his current gig running a 40,000-square-foot high-tech lab. “I had uncles with half fingers. I respect that—doing things with your hands, creating things,” he says. “I feel that I’m working with my hands, but just in a different kind of way.”
To a chemist, atoms are like so many Lego blocks to arrange and rearrange at will. Add a hydroxyl here, a phosphate there, and react with various other chemicals to get the desired color, hardness, transparency or other properties. “If we can draw a molecule, if it doesn’t violate some fundamental law, we probably can make it,” Warner says.
But chemistry was invented at a time when people weren’t thinking about the environmental impacts. Raw materials are typically derived from fossil fuels. Turning them into the desired product can be a multistep process involving hazardous reagents (chemicals that react with the target material) and solvents (liquids or gases that provide an environment for the reaction to take place). Reactions often generate more unwanted than wanted chemicals. In making pharmaceuticals, for example, it is not uncommon to end up with 25 to 100 pounds of waste for every pound of medication.
Green chemistry starts with renewable resources such as plants or microorganisms, recycles its reagents, uses less hazardous solvents, and streamlines complicated processes. For example, in 2006 Pfizer changed the way it makes its nerve-pain drug Lyrica, substituting two plant-based enzymes for a common metallic catalyst called Raney nickel. The process now occurs at room temperature and in water, takes four instead of 10 steps, and has slashed waste and energy use by more than 80 percent.
Why so slow?
Green chemistry is elegant. It’s sensible. It has the potential to improve public health and enhance the economy. But if everyone loves green chemistry—scientists, environmentalists, politicians, corporate leaders—then why hasn’t it been more successful? After 15 years of innovation, the chemical industry is as toxic as ever. The politicians who lavish funding on nanotech dole out pathetically little to green chemistry. The universities that train chemists still do not require students to take a single course in toxicology. And green chemistry is far from becoming a household phrase.
To many observers, the answer is clear: What’s needed is more regulation. “One way to think about it is to ask yourself: ‘What is the purpose of government? Why isn’t everything done by voluntary exchange among willing buyers and sellers?’ The answer is, of course, that a lot of important things that need doing won’t be done voluntarily,” says Edward Woodhouse, a political scientist at Rensselaer Polytechnic Institute in Troy, N.Y. “It does require stick as well as carrot.” Wilson and his Berkeley colleagues have acted on that principle; they helped craftthe nation’s first green-chemistry laws, enacted in 2008 in California. These laws require the state to identify, prioritize and take action on chemicals of concern, to encourage safer alternatives, and to make hazard information available to the state’s businesses and to the public.
Warner is all for transparency, but being a chemist himself, he knows how his colleagues think, and he’s concerned that if green chemistry becomes mandatory, industrial chemists will misunderstand it, writing it off as a policy-wonk proposal when in fact it is solid science, built on the core principles of traditional chemistry. Warner favors the “build a better mousetrap” philosophy: Do green chemistry by making alternatives that are not only safer but effective and economical, and chemical companies will eagerly adopt them.
But others insist that until heavyweights like Dow and ExxonMobil are forced to own up to the dangers of their chemicals, smaller companies developing clean alternatives won’t be able to compete. “Some academics say, ‘If we had enough students and research dollars, then wonderful new substances would flow from our labs and the world would beat a path to our door,'” CIEL’s Ditz says. “But if no one can distinguish between a green molecule and a toxic molecule, it is almost impossible for safer products to break into the market.”
No shift this big happens without conflict, and outrage, Woodhouse says. Average people need to know and care enough about chemical hazards to pressure business and political leaders for change. “Most people have no idea that many of the things in their houses are a danger to them,” he says. “I don’t think that the urgent need for a benign chemical transformation has been put out very effectively.”
In addition, even when scientists come up with nontoxic, cost-saving technologies, they don’t always see the light of day. The up-front expense of redesigning factories often eclipses the potential long-term savings. “Your plants are set up to run nonstop. Any downtime, even if it’s going to save you a million dollars later, is costing you money now,” Chemical Heritage’s Roberts says.
Warner’s concern is that when government gets ahead of science, the effort often backfires. “The ban will say, ‘Use the best available technology.’ If the best available technology is nasty, the ban becomes a license to use that technology,” he says. “You can’t legislate an invention, only encourage it.”
The other side of the coin, however, is that sometimes when government gets ahead of science, science rushes to catch up. That happened in the mid-1990s, when the chemical company Rohm and Haas learned that a ban on tin-based marine paints was in the works. Tin-based paints had been used on ships’ hulls for years because they discouraged the growth of barnacles, algae, bacteria and other unwanted hitchhikers. But tin is toxic and it was accumulating in fish, seabirds and other animals. Japan banned tin-based paints in 1992 and other nations were poised to follow suit. Rohm and Haas had never made ingredients for marine paint—and without the pending ban it would not have tried, because tin-based paint manufacturers dominated the market. But Rohm and Haas already had a mildew-fighting chemical t hat acted as a wood preservative . By adapting that active ingredient, company scientists developed Sea-Nine, a chemical that kills marine organisms by reacting with their own chemistry, breaking down into nonhazardous components in the process.
However it happens, changing worldviews takes time. It took two decades or more for global warming to gain any serious traction. Now it is seen as an opportunity to develop a whole new sector of the economy: alternative energy. The same could happen for green chemistry, as a demand for cleaner products drives innovation.
What everyone agrees on is that, ultimately, green chemistry principles must become so integrated into mainstream chemistry that the term loses its meaning. Ironically, we’ll know that green chemistry has succeeded when it disappears. “The day that everyone from kindergarten students on up gets it, we don’t need the field of green chemistry anymore,” Warner says. “That is my goal, for it to be just the way everybody sees science.”
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A GREEN CHEMISTRY PRIMER
To explain the goals of green chemistry, John Warner uses the metaphor of the toolbox. Rather than wrenches, nuts and bolts,the drawers in the chemical industry’s “toolbox” contain commonly used processes, such as ways to make carbon compounds or oxidation-reduction reactions. Most of these processes involve hazardous chemicals. Green chemists aim to create a new toolbox filled with less harmful alternatives, so that in the future when chemists set out to design a molecule, they’ll be able to put their hands on benign tools to get the job done.
Here are some promising new technologies destined for the green-chemistry toolbox.
TAMLs: There’s no pretty way to say it—TAML is short for tetra-amido macrocyclic ligand—but these apparently harmless chemicals break down a variety of stubborn pollutants, including pesticides, dyes and industrial runoff. Developed by Terrence Collins, a chemist at Carnegie Mellon University in Pittsburgh, TAMLs mimic the enzymes in our bodies that have evolved to fight off toxic assaults. Collins and his team worked for two decades to develop these smaller, easy-to-build versions of biological enzymes. When combined with hydrogen peroxide, TAMLs neutralize many contaminants by breaking their chemical bonds.
Noncovalent derivatization: A longtime passion of Warner’s (his license plate reads “NCD”), noncovalent derivatization is chemistry with a light touch. Covalent bonds are the strong connections between atoms that hold molecules together. Normally, when chemists are dissatisfied with some aspect of a molecule they are creating, they alter its structure by breaking or adding covalent bonds. Such changes can involve multiple steps and hazardous ingredients. Warner’s breakthrough was to posit that sometimes there’s no need to create a new molecule. Simply combine the existing molecule with another substance that interacts with it, and the transient forces between them can effect the desired change. “With no energy they find each other and form,” he says. “Why does a bunch of lipids fold up to form a cell membrane? Why does DNA form a double helix? It’s always these weak molecular structures.”
Liquid CO2: Most of us know carbon dioxide as a gas (we exhale it) or a solid (think: dry ice in fog machines). But when you put carbon dioxide under pressure, it becomes a liquid. Liquid CO2 is a benign substitute for the nasty solvents typically used to decaffeinate coffee. Just mix it with green coffee beans, then take the pressure off. The carbon dioxide evaporates, leaving behind a pile of white powder—caffeine. Do the same thing to dirty clothes and you extract oils and grime without using perchloroethylene, the notorious dry cleaning chemical.
An article by Vanessa O’Connell in the Wall Street Journal discusses rising consumer interest in environmentally friendly products, the dubious claims made by manufacturers and the resulting lawsuits and government actions. The story sheds light on a growing concern about false advertising, but it would have benefited from further discussion of government efforts to remedy the situation.
The article describes how the Federal Trade Commission (FTC) is attempting to referee various seals of approval, eco-labels and other marketing schemes that advertise green benefits like biodegradability. The FTC’s Green Guides for manufacturers provide some guidance but have not been revised since 1998. A current review of the outdated guides may address some of the marketing changes since then.
The story also shows how transparency with respect to self-endorsement or third-party approvals has become an issue. For example, SC Johnson’s Greenlist program won a Presidential Green Chemistry Challenge Award from the U.S. Environmental Protection Agency (EPA), yet the way the Greenlist system is applied to products remains proprietary and the labels are added at the company’s sole discretion.
Other government agencies are taking steps to address the concerns highlighted in the article. For example, the EPA’s Design for the Environment Program (DfE) offers labels for a variety of consumer products deemed to be best-in-class. The DfE scheme calls for continuous improvement in eco-friendly attributes and is based on strict, transparent criteria. Legislation introduced earlier in April would give the EPA greater authority to recognize safer alternatives to hazardous products in this way.
By mentioning these intitiatives, the reporter would have added important information for consumers who are concerned about the issue of false claims.
The story would have been more informative if the reporter had discussed the challenges that remain before algae fuels or plastics can become widespread. It is still not clear how algae can be produced sustainably on a large scale.
Reporter Alyssa Danigelis describes a new plastic that can be made with up to 50 percent algae. The company developing it hopes it will be 100 percent algae in a few years. Danigelis draws attention to the major green benefits of this new technology: it uses what would probably be a waste material from biodiesel production, it should not have any impact on the food supply, and further research and development could lead to a compostable material.
The 50 percent algae product also contains polypropylene (PP), a plastic often encountered in everyday life, for example, in microwaveable food containers. Such blends of natural and synthetic materials are not completely biodegradable but they often help to reduce consumption of limited resources.
By using algae left over from fuel extraction, this new plastic supports the idea of a “biorefinery.” The oil, coal and gas industries don’t just produce fuels – they produce the chemical building blocks for everything from industrial solvents to pharmaceuticals, leaving almost nothing to waste. Similarly, biofuel production will be more competitive if all of the raw materials are used productively. Plastic from algae is a step in that direction.
However, water, nutrient and energy demands can be extremely high and these issues are just as serious as whether the technology will compete with food production. Until the science is worked out, the “greenness” of algae – beyond its actual color – is not yet certain. The story could have made this more clear.
A new way of concocting a promising “green” plastic called polycaprolactone (PCL) makes it clearer and more biodegradable – critical features for alternatives to PVC plastic or other conventional packaging materials.
PCL was transformed into a more transparent plastic when two different varieties of the same starting material were combined in the laboratory. The blends broke down faster when buried in a compost. The results show that the new blends improve traits – transparency and degradability – necessary to develop PCL into a viable plastic product.
PCL degrades easily and thus has been studied for decades as an alternative plastic for use in agriculture, medicine, pharmacy, biomedical and as an environmentally friendly material for packaging. Because it has some disadvantages – for example it cannot form a transparent film – it must be blended with other plastics in industrial applications.
PVC, like many other plastics, is not biodegradable, and therefore, it persists in the environment. PVC is rigid unless other chemicals are added to the formulation. Phthalates are among the most commonly used additives to make PVC flexible. Human health concerns have been raised about exposures when these chemicals migrate out of the plastic, especially effects on the male reproductive system.
Ironically, PVC is often chosen for blending with PCL because the two polymers can be mixed very easily. This takes away from the environmental benefits of PCL, since in the blended plastic, after the PCL degrades, the PVC persists just as it normally would on its own.
The new PCL plastic reported in this study does not use PVC. It can be fine-tuned so that the transparency increases from 8 percent to 45 percent and the plastic films break down much more quickly than ordinary PCL. The blends were less flexible and stretchy, but the researchers did not discuss whether the impact this would have on a potential packaging material.
The technique that led to the new plastic was a method of changing the structure of the PCL chain. Ordinary PCL and the new PCL contain the same repeating units, but the new PCL is not perfectly linear. It has branches, forcing the chains to take on a different overall shape. There are many different ways to make branched-chain PCLs, so more research could increase the number of options for manufacturers who want to use environmentally friendly plastics.