John Simonsen

John Lionel Simonsen (22 July 1884, Levenshulme, Manchester – 20 February 1957, London) was an English organic chemist.

Simonsen, whose parents came from Denmark (his father was a merchant), attended the Manchester Grammar School and studied at the University of Manchester, where he obtained his bachelor's degree with top grades in 1904, a Ph.D. in 1909 and was a student of William Henry Perkin Jr. In 1907 he became an assistant lecturer and demonstrator in Manchester. Before the First World War he was in Madras, where from 1910 he was professor colleague of Charles Gibson at the Presidency College. While Gibson went to England after the war broke out, Simonsen stayed in India, where he was an oil controller and advisor to the Indian Munitions Board. He also founded the Indian Science Congress Association in 1914, whose secretary he was until 1926. From 1919 to 1925 he was chief chemist at the Forest Research Institute and College in Dehra Dun and from 1925 to 1928 professor at the Indian Institute of Science in Bangalore. In 1928 he returned to England, where he was first Gibson's colleague at Guy's Hospital in London. In 1930 he became a professor at the University of Wales in Bangor (Wales) where he remained until 1942. From 1943 to 1952 he was research director of the Colonial Products Research Council (later Tropical Products Research Council). In 1945 he became a member of the Agricultural Research Council.

Simonsen dealt with the chemistry of natural products, especially terpenes and sesquiterpenes. For example, he discovered 3-Carene in Indian turpentine. He often worked with AE Bradfield and AR Penfield, director of the Museum of Art and Sciences in Sydney, who provided him with interesting new natural products. He was primarily an experimenter and had little interest in theory.

A visit with Robert Robinson to the Caribbean and the US in 1944 led to the establishment of the Microbiology Research Institute in Trinidad and the effective control of mosquitoes on the British Guiana coast, which significantly reduced child mortality. In 1946 he visited South and East Africa with Ian Heilbron.

In 1950 he received the Davy Medal. From 1932 he was a fellow of the Royal Society. In 1949 he was ennobled. In 1949 he received the Ernest Guenther Award from the American Chemical Society. He was an honorary doctorate in St. Andrews, Malaysia and Birmingham.

Ewart Jones is one of his doctoral students.

He married in 1913 and had a daughter.