The Greening of Chemistry

A number of theories were proposed over the next 15 years, but it wasn’t until 1971 that Yves Chauvin of the Institut Français du Pétrole along with student Jean-Louis Hérisson identified the process: a metal carbene was kicking off the reaction. Chauvin called it a molecular dance, in which one partner was cast off for another. Twenty years later, Richard Schrock of the Massachusetts Institute of Technology uncovered which metals could be used as catalysts. One group of molybdenum catalysts was particularly effective at rearranging the compounds’ double bonds. But these were highly reactive and sensitive to both oxygen and moisture. They were far from perfect. In 1992, Robert Grubbs, of the California Institute of Technology, discovered a ruthenium catalyst that was stable in air and more selective than Schrock’s catalysts.

Together these chemists’ contributions explained and developed the olefin metathesis reaction, creating a new tool to shorten the route to a desired molecule and reduce the number of unwanted and often hazardous by-products. Its discovery opened up new opportunities in the industrial production of pharmaceuticals, plastics, and other materials.

Their work also earned Chauvin, Schrock, and Grubbs the Nobel Prize in Chemistry in 2005. Per Ahlberg, a member of the Royal Swedish Academy of Sciences and of the Nobel Committee for Chemistry, proclaimed during his presentation speech, “Metathesis also saves energy and material and is kind to the environment. It takes us a step toward a ‘greener’ future.” The occasion marked the first time that the Royal Swedish Academy of Sciences recognized green chemistry—the design of chemicals and processes that reduce or eliminate the use and production of substances hazardous to humans and the environment—but the field had been steadily gaining ground for more than a decade.

Incentivizing Green Practices

Legislation has controlled the use, treatment, and disposal of chemicals since the 1960s. This traditional “command and control” regulatory approach cost businesses billions of dollars yet still allowed the release of several billion pounds of chemical waste into the environment every year. That was set to change in 1990, when the U.S. Congress passed the Pollution Prevention Act, which sought to reduce pollution at its source.

A year earlier, Paul Anastas was a young synthetic organic chemist at Brandeis University. He had just earned a Ph.D. in chemistry and had a promising career in cancer research ahead of him, but he yearned for something more. Instead of designing molecules to fight cancer and working as an industrial consultant, he wanted to develop a framework that prevented the occurrence of cancer in the first place. That meant preventing hazardous wastes from being released into the environment by redesigning chemical processes and products at the molecular level so that they were “benign by design.” In 1989 Anastas accepted a position at the Office of Pollution Prevention and Toxic Substances at the U.S. Environmental Protection Agency (EPA); by 1991 he had coined the term green chemistry.

Even with the Pollution Prevention Act in place, there was little financial motivation for industry—or academia—to look for alternative chemical processes. The EPA and the National Science Foundation (NSF) launched a slew of grant programs in hopes of eliciting some solutions. In 1991 the EPA launched a green chemistry program. One part of the program, “Alternative Synthetic Pathways for Pollution Prevention,” offered grants to design and synthesize chemicals that would curb the production of pollutants. In 1992 the NSF teamed up with the nonprofit Council for Chemical Research to develop the “Environmentally Benign Chemical Synthesis and Processing” research program. It dispersed $950,000 among projects that sought to develop more selective catalysts and new or cleaner reactions that would replace those requiring toxic feedstocks or solvents, and others that would eliminate aerosol particles.

It was around this time that Anastas crossed paths with a chemist at the Polaroid Corporation named John Warner. Warner had developed a process called noncovalent derivatization to stabilize the molecules in multilayered instant film and keep the film from deteriorating while it sat on store shelves. The chemistry was simple and less toxic; it satisfied the principles of green chemistry that the EPA was trying to promote. The pair became advocates for the future of green chemistry, speaking on the topic whenever they could.