Charles Frederick Koelsch (31 January 1907 - 24 December 1999) was an American organic chemist who spent his faculty career at the

University of Minnesota The University of Minnesota, formally the University of Minnesota, Twin Cities, (UMN Twin Cities, the U of M, or Minnesota) is a public university, public Land-grant university, land-grant research university in the Minneapolis–Saint Paul, Tw ...

Education and academic career

Koelsch was born in Boise, Idaho in 1907 in a family of German descent. He attended the

University of Wisconsin A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, t ...

and earned his bachelor's degree in 1928 and his Ph.D. from the same institution in 1931, working under the supervision of

Samuel M. McElvain Samuel Marion McElvain (December 9, 1897 – April 11, 1973) was an American organic and synthetic chemist who spent his research career on the faculty of the University of Wisconsin. Academic career McElvain studied first at Washington Univ ...

. After a postdoctoral fellowship at

Harvard University Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher le ...

with

Elmer Peter Kohler Elmer Peter Kohler (November 6, 1865 - May 24, 1938) was an American organic chemist who spent his career on the faculty at Bryn Mawr College and later at Harvard University. At both institutions he was notable for his effectiveness in teaching. ...

, Koelsch was recommended for a position at the University of Minnesota by Lee Irvin Smith. He joined the faculty there as an instructor in 1932 and became an assistant professor in 1934. Koelsch was awarded the

ACS Award in Pure Chemistry The American Chemical Society Award in Pure Chemistry is awarded annually by the American Chemical Society (ACS) "to recognize and encourage fundamental research in pure chemistry carried out in North America by young men and women." "Young" me ...

in 1934. He advanced to

associate professor Associate professor is an academic title with two principal meanings: in the North American system and that of the ''Commonwealth system''. Overview In the ''North American system'', used in the United States and many other countries, it is a ...

in 1937 and

full professor Professor (commonly abbreviated as Prof.) is an academic rank at universities and other post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin as a "person who professes". Professors ...

in 1946. He remained at the University of Minnesota until his retirement, assuming

professor emeritus ''Emeritus'' (; female: ''emerita'') is an adjective used to designate a retired chair, professor, pastor, bishop, pope, director, president, prime minister, rabbi, emperor, or other person who has been "permitted to retain as an honorary title ...

status, in 1973. Through much of his academic career, Koelsch also served as an industry consultant, working first with Smith, Kline & French and later with Sterling Drug and

Union Carbide Union Carbide Corporation is an American chemical corporation wholly owned subsidiary (since February 6, 2001) by Dow Chemical Company. Union Carbide produces chemicals and polymers that undergo one or more further conversions by customers befor ...

. During his work at Harvard, Koelsch attempted to publish a paper describing an unusually stable

radical Radical may refer to: Politics and ideology Politics *Radical politics, the political intent of fundamental societal change *Radicalism (historical), the Radical Movement that began in late 18th century Britain and spread to continental Europe and ...

compound, but it was rejected at the time on the grounds that the compound's properties were unlikely to describe a radical. Subsequent experimental evidence and

quantum mechanics Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, ...

calculations suggested his interpretation of the original experiment was correct, resulting in the publication of the paper nearly 25 years after the original experiments. The compound - 1,3‐bisdiphenylene‐2‐phenylallyl (BDPA) - is now often referred to as the " Koelsch radical".

Personal life

Koelsch married his wife Helen in 1938 and the couple had three children. He was a ham radio enthusiast. He died in

Rochester, Minnesota Rochester is a city in the U.S. state of Minnesota and the county seat of Olmsted County. Located on rolling bluffs on the Zumbro River's south fork in Southeast Minnesota, the city is the home and birthplace of the renowned Mayo Clinic. Acco ...

in 1999.

References

{{DEFAULTSORT:Koelsch, C. Frederick 20th-century American chemists American organic chemists University of Minnesota faculty University of Wisconsin–Madison alumni 1907 births 1999 deaths People from Boise, Idaho Scientists from Idaho