Another important initiative is called green chemistry,⁴ developed as part of efforts to reduce pollution at the source; it is defined as “the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances.”⁵ Originated in the United States (where prestigious awards for accomplishments in this area are given annually), it is increasingly becoming a worldwide program.

Benign processes help make chemical plants into good neighbors, and their operators into good citizens, but the products themselves are now being examined with a new perspective. For example, DDT (invented by Paul Müller, who received a Nobel Prize in 1948 for this invention) was an effective insecticide that greatly reduced the occurrence of insect-borne diseases such as malaria. However, its widespread use caused problems, because it is too stable. DDT persists in the environment and enters the food chain, a phenomenon that led to the nearly complete elimination of DDT use after it was shown to interfere with bird reproduction. At one point it was believed that persistence was a good thing, since the insecticide would keep on working, but it is now recognized that persistent chemicals can accumulate in the environment and lead to new or unexpected problems.

A similar situation is found with the herbicides that help make agriculture more productive by controlling weeds. Advantages are now recognized for herbicides having limited persistence, lasting long enough to do the job and then harmlessly disappearing.

Persistence was also the unforeseen problem with the role of chlorofluorocarbons (CFCs) in degrading the earth’s ozone layer. CFCs were invented to replace toxic and dangerous gases (such as sulfur dioxide) that had been used as the working fluid for compressors in early refrigerators and air conditioners. Indeed, CFCs are so unreactive under normal conditions that they are quite harmless to humans and other living things. However, they are so stable that they diffuse throughout the atmosphere. When they reach the stratosphere—where the ozone layer is found—the greater intensity of high-energy radiation from the sun finally causes slow decomposition of the CFCs. This decomposition process produces chlorine atoms that catalyze the destruction of ozone in a chemical sequence that is now well understood. For elucidating these chemical processes in the stratosphere, Paul Crutzen, Mario Molina, and F. Sherwood Rowland received a Nobel Prize in 1995.

While the high stability and persistence of CFCs provided a major advantage for such applications as refrigeration and air conditioning, escape of the gases into the air has resulted in unacceptable changes in the upper atmosphere. The solution to the problem is to invent new relatives of CFCs that are adequate coolants but are less environmentally persistent. Chemists have indeed created such new substances, which are now replacing CFCs.

Front Matter (R1-R14)

Executive Summary (1-10)

1 Introduction (11-15)

2 The Structures and Cultures of the Disciplines: The Common Chemical Bond (16-21)

3 Synthesis and Manufacturing: Creating and Exploiting New Substances and New Transformations (22-40)

4 Chemical and Physical Transformations (41-54)

5 Isolating, Identifying, Imaging, and Measuring Substances and Structures (55-70)

6 Chemical Theory and Computer Modeling: From Computational Chemistry to Process Systems Engineering (71-94)

7 The Interface with Biology and Medicine (95-122)

8 Materials by Design (123-147)

9 Atmospheric and Environmental Chemistry (148-159)

10 Energy: Providing for the Future (160-170)

11 National and Personal Security (171-179)

12 How To Achieve These Goals (180-194)

Appendix A: Biographical Sketches of Steering Committee Members (195-201)

Appendix B: Statement of Task (202-202)

Appendix C: Contributors (203-208)

Index (209-224)