Charles Frederick Koelsch (31 January 1907 - 24 December 1999) was an American organic chemist who spent his faculty career at the University of Minnesota. ^{[1] [2] [3]}

Education and academic career

Koelsch was born in Boise, Idaho in 1907 in a family of German descent. ^[3] He attended the University of Wisconsin 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. ^{[2] [3]} After a postdoctoral fellowship at Harvard University with Elmer Peter Kohler, Koelsch was recommended for a position at the University of Minnesota by Lee Irvin Smith. ^[3] 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 in 1934. ^{[3] [2]} He advanced to associate professor in 1937 and full professor in 1946. ^[1] He remained at the University of Minnesota until his retirement, assuming professor emeritus status, in 1973. ^{[1] [3]} 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. ^[3]

During his work at Harvard, Koelsch attempted to publish a paper describing an unusually stable radical 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 calculations suggested his interpretation of the original experiment was correct, resulting in the publication of the paper nearly 25 years after the original experiments. ^{[3] [4]} The compound - 1,3‐bisdiphenylene‐2‐phenylallyl (BDPA) - is now often referred to as the " Koelsch radical". ^{[5] [6]}

Personal life

Koelsch married his wife Helen in 1938 and the couple had three children. He was a ham radio enthusiast. ^{[2] [3]} He died in Rochester, Minnesota in 1999. ^[2]

References