The unsung architect whose BET method transformed catalysis from an empirical art into a sophisticated science
In the world of modern science, few concepts are as fundamental as surface area in materials research. From the catalytic converters in our cars to the pharmaceuticals we take, understanding how gases interact with solid surfaces has been pivotal to countless technological advances. At the heart of this understanding stands Paul H. Emmett, a chemist whose work transformed catalysis from an empirical art into a sophisticated science and whose BET method remains a standard laboratory technique nearly a century after its development 1 5 .
Fundamental to materials science and catalysis research
Transformed from empirical art to sophisticated science
Paul Hugh Emmett's journey to scientific prominence began in Portland, Oregon, where he was born on September 22, 1900 2 7 . His early life was far from privileged—his father worked for the railroad, and for a period during his childhood, the family actually lived in a rail car while his mother worked as a cook for the railroad crew 2 7 .
Emmett's path to chemistry might never have happened if not for a perceptive high school English teacher who noticed his aptitude for mathematics and languages.
Interestingly, Green had a similar impact on another student—Linus Pauling, who would later win two Nobel Prizes 5 . This connection would become one of the most significant of Emmett's life, both personally and professionally. Emmett and Pauling became close friends, attending both Oregon Agricultural College (now Oregon State University) and the California Institute of Technology together 2 7 .
| Year | Event | Significance |
|---|---|---|
| 1900 | Born in Portland, Oregon | Birth of future catalysis pioneer |
| 1918-1922 | Undergraduate studies at Oregon Agricultural College | Earned BS in Chemical Engineering |
| 1922-1925 | PhD at California Institute of Technology | Studied under Arthur F. Benton; began catalysis research |
| 1925 | Published paper with Linus Pauling | Collaboration on crystal structure of barium sulfate |
| 1926 | Joined Fixed Nitrogen Research Laboratory | Beginning of professional focus on catalysis |
Inspired by chemistry teacher William Green, who also taught Linus Pauling
Earned BS in Chemical Engineering (1918-1922)
PhD in physical chemistry (1925) under Arthur F. Benton
Joined in 1926, beginning professional focus on catalysis
After completing his doctorate, Emmett's career path led him to the Fixed Nitrogen Research Laboratory (FNRL) in Washington, D.C., in 1926 2 5 . This laboratory had been established to continue wartime efforts to develop an American synthetic ammonia industry, crucial for both fertilizers and explosives 5 .
A fundamental problem plagued his research: while scientists could observe how effectively catalysts worked, they had no reliable way to measure the actual surface area of catalyst particles 5 . This was critical because catalysis occurs on surfaces—the more surface area available, the more sites where chemical reactions can occur.
The breakthrough came when Emmett noticed that the beginning of the linear section in nitrogen adsorption curves might signal the completion of a monolayer of gas molecules covering the catalyst surface 5 . He collaborated with Stephen Brunauer, who was conducting the experimental work, and they brought their findings to Edward Teller (who would later become famous as the "father of the hydrogen bomb") 2 5 .
Revolutionary method for surface area calculation
| Component | Description | Significance in Surface Area Calculation |
|---|---|---|
| P | Pressure of gas | Measured during experiment |
| P₀ | Saturation pressure of gas | Known property of the gas at specific temperature |
| V | Volume of gas adsorbed | Measured during experiment |
| Vₘ | Volume of gas for monolayer coverage | Calculated from equation; key to surface area |
| C | BET constant | Related to heat of adsorption |
Emmett's scientific contributions extended far beyond the BET equation. During World War II, he joined the Manhattan Project in 1943, leaving his position as chair of the Chemical Engineering Department at Johns Hopkins University 2 7 . For 16 months, he served as a division chief at Columbia University, where his team worked on the crucial challenge of separating uranium isotopes and developing corrosive uranium hexafluoride gas needed for the atomic bomb 2 7 .
| Years | Institution | Key Contributions and Research Focus |
|---|---|---|
| 1926-1937 | Fixed Nitrogen Research Laboratory | Ammonia catalysis; development of BET method |
| 1937-1943 | Johns Hopkins University | Chair of Chemical Engineering; BET theory published |
| 1943-1944 | Manhattan Project | Uranium isotope separation; uranium hexafluoride development |
| 1944-1955 | Mellon Institute | Petroleum research; radioisotope tracers in catalysis |
| 1955-1971 | Johns Hopkins University | W.R. Grace Professor of Chemistry; catalytic cracking research |
| 1971-1985 | Portland State University | Surface area of soils; coal porosity; continued catalysis research |
Throughout his diverse research endeavors, Emmett utilized several key materials and techniques that defined his scientific contributions:
Paul Emmett's career spanned six remarkably productive decades, during which he authored 164 scientific publications 2 . Even after formally retiring from Johns Hopkins University in 1971, he continued active research as a visiting professor at Portland State University until shortly before his death 2 7 .
The recognition of his contributions was extensive. He was elected to the National Academy of Sciences in 1955 and received numerous honors, including the Kendall Award from the American Chemical Society and several honorary doctorates 2 7 . Perhaps most significantly, the Paul H. Emmett Award was established in his honor in 1972 by the Catalysis Society of North America, recognizing fundamental contributions to the field of catalysis 2 7 8 .
On a personal level, Emmett's life intertwined beautifully with his scientific colleague Linus Pauling. After Emmett's first wife, Leila Jones, died in 1968, he married Pauline Pauling, Linus Pauling's sister, in 1976—making the two scientific collaborators brothers-in-law late in life 2 7 .
His work exemplifies how basic scientific research, driven by curiosity and meticulous experimentation, can transform entire fields of technology and industry. From synthetic fertilizers to petroleum refining to modern nanomaterials, the molecular world that Paul Emmett helped map continues to shape our physical world in countless ways.