<p>Frank Henry Westheimer (February 4, 1911 – April 8, 2007) was an American chemist and a pioneer in the field of organic chemistry. He made significant contributions to the understanding of chemical reactions and the mechanisms of organic compounds. He is most well-known for his work in the areas of nucleophilic substitution, electrophilic substitution, and chemical kinetics.</p><p></p><p>Westheimer was born in New York City and received his Bachelor's degree in chemistry from Harvard University in 1932. He then went on to earn his Ph.D. in chemistry from the University of Chicago in 1935. After completing his Ph.D., Westheimer worked as a postdoctoral researcher at the California Institute of Technology and at the University of Chicago before joining the faculty at Harvard University in 1937.</p><p></p><p>Westheimer's research focused on understanding the mechanisms of chemical reactions and the behavior of organic compounds. He made significant contributions to the understanding of nucleophilic substitution, electrophilic substitution, and chemical kinetics. He also conducted research on the chemistry of enzymes, the chemistry of natural products, and the chemistry of antibiotics.</p><p></p><p>Westheimer's work in chemical kinetics was particularly groundbreaking. He developed a method to measure the rate of chemical reactions, known as the Westheimer method, which is still widely used today. He also developed a theory to explain the behavior of enzymes, which is known as the "transition-state theory."</p><p></p><p>Westheimer was widely recognized for his contributions to the field of chemistry, and he received numerous awards and honors throughout his career. In 1963, he was awarded the National Medal of Science, and in 1971, he was awarded the Priestley Medal, the highest honor of the American Chemical Society.</p><p></p><p>Frank Henry Westheimer was an American chemist and a pioneer in the field of organic chemistry. He made significant contributions to the understanding of chemical reactions and the mechanisms of organic compounds and was widely recognized for his contributions to the field of chemistry and received numerous awards and honors throughout his career. His work in chemical kinetics was particularly groundbreaking and his method is still widely used today. He also developed a theory to explain the behavior of enzymes which is known as the "transition-state theory."</p><p></p><p></p>