Green chemistry.

Gilbert's chemistry sets, those that many of today's practicing chemists received as children, proved to be the spark that ignited many a lifelong exploration of the wonders of chemistry. While DuPont was espousing its contributions to the world with its motto, "Better living through chemistry," children were using the popular Gilbert's chemistry sets to perform the simplest experiments and viewing them as wonders to behold. The rewards for the chemists' subsequent work are obvious today. Developments in water treatment, waste disposal methods, agricultural pesticides and fungicides, polymers, materials science, detergents, petroleum additives, and so forth, have all contributed to the improvement in our quality of life. But all of these advances came with a price tag-pollution. Scientists and engineers from both the chemical industry and the academic world have made efforts to correct pollution problems by the more extensive use of "green" chemistry concepts, i.e., development of methodologies and products that are environmentally friendly. The chemical industry itself also has instituted programs, such as Responsible Care (1), to address pollution problems. How well this program will function is still not clear, as has been addressed previously on these same pages (2. An awareness of green chemistry concepts seems to be growing. In a recent article that was published in a Supplement issue of Environmental Health Perspectives, Gray and Bergbreiter (3) described the use of polymeric smart materials that have direct applications in reducing pollution from the chemical industry. Polymeric smart materials are substances that sense and respond to some change in their molecular environment in a controlled and reproducible manner. Because catalysts are used extensively in the chemical industry, failure to recover them from reactors can be a source of significant industrial waste. A partial solution was found in the use of smart catalysts. Thermoresponsive polymer-bound catalysts were developed and designed so that solubility was inversely related to temperature. Thus, catalysts can be recovered by a simple filtration step after an adjustment of the temperature of the reacting solution. As an added bonus, this type of catalyst could also be used to self-regulate exothermic reactions, i.e., as the temperature increased the solubility of the catalyst decreased, thus modulating the reaction. Recognizing the importance of reducing pollution at its source, Congress passed the Pollution Prevention Act in 1990. In response, the U.S. Environmental Protection Agency (EPA) launched the green chemistry program (4); the program's goal was to promote the development of …