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Chemical Reaction: Green Chemistry—Safer from the Start

Contact Author Steve Herman
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“Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in beer.” —Dave Barry

Chemical. The mere word triggers fear and hostility in many people. Images of the Exxon Valdez and Chernobyl merge into a generalized, and irrational, view of the value of technology in the world. Fortunately, a countermovement is underway to make scientific activity safer, and to communicate to the public the innumerable ways that science makes the world better.

Many SCC chapters have enjoyed presentations by John Warner, Ph.D., on green chemistry. Warner, a professor at University of Massachusetts Lowell, has been a dedicated advocate of a new type of environmentally informed chemistry, coauthoring the classic text—Green Chemistry (Oxford Press, 1998), advocating programs in Washington, D.C., gently prodding the American Chemical Society (ACS) into embracing the new way of doing science, and reaching out to the general public. This column summarizes the history and principles of green chemistry, and shows how extensive this approach to science has become in a relatively short time with the government, academia and industry.

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Warner has an especially interesting Web site, www.greenchemistry.uml.edu, with a 45-minute video outlining his career. He had a long and successful stint in industry before commencing his equally notable time in academia. He is on the board of the ACS, has recently won a presidential teaching award (complete with a visit to the Oval Office), and his advocacy has resulted in green chemistry legislation passing Congress. With many demands on his time and enough accomplishments for any scientist, Warner makes time to appear at as many technical meetings as possible, realizing the importance of spreading the word to enable the new chemistry to take hold as broadly and deeply as possible.

The Greening of Chemistry

The heart of green chemistry is almost self-evident once it is described (see sidebar on p.54). A lot of resources are dedicated to regulatory, environmental and safety concerns. Warner realized that some major chemical companies spend as much money on regulatory and safety concerns as they spend in R&D—sums in the hundreds of millions of dollars. The fundamental concept of green chemistry is simplicity itself: Why not make products safe from the beginning? Then the safety, environmental and regulatory issues, with their attendant expense in time and money, would melt away. In the process, as a possible halo effect, the general public might no longer view the industry as insensitive purveyors of toxic materials.

Warner tells a story that illustrates the current priorities of chemical education. To get his doctorate, he was locked in a room and required to translate a technical paper from German to English, and another paper from French to English. Never again in his long and illustrious career did his work require this ability. At the same time, he never was provided a course in toxicology or environmental safety. Safety simply was never a concern of chemical education. The green chemistry departments springing up in the. United States and globally fortunately are rectifying this situation.

Green chemistry got a massive boost with the passage of the Pollution Prevention Act of 1990. The Office of Pollution Prevention encouraged the discovery of new methods, and the improvement of existing chemical products and processes, to make them less hazardous to human health and the environment. In 1991, a program began to provide grants for research projects that included pollution prevention in the design and synthesis of chemicals.

For the principles of green chemistry (see sidebar on page xx) to have effect, they must take hold in schools, in industrial laboratories and in production processes. An example of industry action is provided by Engelhard Organic Pigments, with its Rightfit pigments. Red, orange and yellow pigments historically were created using toxic, heavy metals such as lead, chromium and cadmium. Engelhard developed azo pigments that contain calcium, strontium or barium. They have very low potential toxicity and are manufactured in aqueous medium, eliminating the polychlorinated intermediates and organic solvents associated with traditional materials.

Key Developments

Ryoji Noyori, the 2001 Nobel prize winner in chemistry, has identified three key developments in green chemistry: use of supercritical carbon dioxide as a green solvent, aqueous hydrogen peroxide for clean oxidations and the use of hydrogen in asymmetric synthesis. On October 5, 2005, France’s Yves Chauvin and Americans Robert H. Grubbs and Richard R. Schrock won the 2005 Nobel Prize in chemistry for their work to reduce hazardous waste in forming new chemicals. The trio won the award for their development of the metathesis method in organic synthesis—which focuses on how chemical bonds are broken and made between carbon atoms, and which the Nobel Prize committee likened to a dance in which the couples change partners.

Of course safety and environmental concern is not new for the chemical industry. The American Chemical Council (ACC) started the Responsible Care program in 1988. It is intended to improve the environmental, health, safety and security performance of participating companies. Its latest initiative to burnish the image of chemistry is the “Essential2” campaign sponsored by the ACC. Supporting members include BASF, Dow Corning, 3M, Rohm & Haas, and W.R. Grace. The $35 million budget includes print, television, radio and a Web site. The “Chem Factor” shows the percent of ingredients in everyday items derived from innovations in chemistry. A typical ad shows a woman waking up to a scene where all the contents of her room disappear, showing life without chemistry.

From Nobel Prize research to Green Chemistry departments, from the EPA to industry associations, a massive effort is underway to make chemistry safer, and to communicate its value to the general public. The word “chemical” has been demonized far too long, and these efforts hopefully will create a much more positive image of the industry and its products. Warner symbolizes a new era where safety and concern for the environment are as important as covalent bonds and pH for anyone in the chemical field.



Green Chemistry Defined

Green Chemistry is the utilization of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture and application of chemical products.

Green chemistry is a revolutionary philosophy that seeks to unite government, academic and industrial communities by placing more emphasis on tending to environmental impacts at the earliest stage of innovation and invention. This approach requires an open and interdisciplinary view of materials design, applying the principle that it is better to not generate waste in the first place, rather than disposing or treating it afterward. Environmentally benign alternatives to current materials and technologies must be systematically introduced across all types of manufacturing.

Currently, environmentally benign alternative technologies have proven to be economically superior and function as well or better than more toxic traditional options. When hazardous materials are cut from processes, all hazard-related costs are cut as well, significantly reducing hazardous materials handling, transportation, disposal and compliance concerns.

Given a choice between traditional options and green solutions, business leaders choose responsibly. Unfortunately there is a significant shortage of more responsible green alternatives. Scientists and non-scientists alike can begin to address this technological gap by recognizing the interconnectivity between the construction of materials and environmental protection. There is tremendous untapped opportunity for ingenuity and reward at the chemical design stage; this is the central concern of Green Chemistry.


12 Principles of Green Chemistry

  1. Prevention—It is better to prevent waste than to treat or clean up waste after it has been created.
  2. Atom Economy—Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product.
  3. Less Hazardous Chemical Synthesis—Wherever practicable, synthetic methods should be designed to use and generate substances that possess little or no toxicity to human health and the environment.
  4. Designing Safer Chemicals—Chemical products should be designed to affect their desired function while minimizing their toxicity.
  5. Safer Solvents and Auxiliaries—The use of auxiliary substances such as solvents and separation agents should be made unnecessary wherever possible and innocuous when used.
  6. Design for Energy Efficiency—Energy requirements of chemical processes should be recognized for their environmental and economic impacts and should be minimized. If possible, synthetic methods should be conducted at ambient temperature and pressure.
  7. Use of Renewable Feedstocks—A raw material or feedstock should be renewable rather than depleting whenever technically and economically practicable.
  8. Reduce Derivatives—Unnecessary derivatization—use of blocking groups, protection/ deprotection or temporary modification of physical/chemical processes— should be minimized or avoided if possible, because such steps require additional reagents and can generate waste.
  9. Catalysis—Catalytic reagents (as selective as possible) are superior to stoichiometric reagents.
  10. Design for Degradation—Chemical products should be designed so that at the end of their function they break down into innocuous degradation products and do not persist in the environment.
  11. Real Time Analysis for Pollution Prevention—Analytical methodologies need to be further developed to allow for real time, in-process monitoring and control prior to the formation of hazardous substances.
  12. Inherently Safer Chemistry for Accident Prevention—Substances and the form of a substance used in a chemical process should be chosen to minimize the potential for chemical accidents, including releases, explosions and fires.**

— from PT Anastas and JC Warner, Green Chemistry: Theory and Practice, New York: Oxford Univeristy Press (1998) p 30.


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