Donnan, Frederick George

(b. Colombo, Ceylon, 5 September 1870; d. Canterbury, England, 16 December 1956)

physical chemistry.

Donnan, the son of a Belfast merchant, was born while his parents were temporarily abroad. He was educated at Belfast Royal Academy and at Queen’s College, Belfast; after graduation he spent three years at Leipzig with Wislicenus and Ostwald, then a year at Berlin under van’t Hoff. This unusually long apprenticeship to chemistry was completed with a period spent working with Ramsay at University College, London, to the teaching staff of which he was appointed in 1901. Three years later he became professor of physical chemistry at the University of Liverpool; he was made a fellow of the Royal Society in 1911 and succeeded Ramsay at University College in 1913. Donnan was drawn into industry during World War I, and for several years he worked on problems connected with the manufacture of “synthetic” ammonia and nitric acid, both in London and with the firm of Brunner, Mond in Cheshire. These industrial connections and interests were retained for the rest of his life, and even after his retirement in 1937 he continued to act as a consultant. His London house was destroyed in 1940, and he retired to Kent with his sisters; he was unmarried.

Donnan, having worked with both Ostwald and van’t Hoff, was one of the main agents by whom the “new” physical chemistry was introduced into Britain. Van’t Hoff had interested him in the problems of colloids, soap solutions, and osmotic pressures, and this interest led to his major paper, “The Theory of Membrane Equilibrium in the Presence of a Nondialyzable Electrolyte” (1911). This examined the effect of confining, by means of a membrane, a mixture of ions, one of which cannot pass through the membrane because of its large size. (In the absence of a membrane, the equilibrium of a protein with a salt solution is a similar case.) The theory of the Donnan membrane equilibrium has important applications in colloid chemistry and in the technologies of leather and gelatin, but above all in the understanding of the living cell, where it can give a quantitative account of ionic equilibria both within the cell and between the cell and its environment.

None of Donnan’s subsequent work approaches this in importance. In later years he guided his department in London on a very loose rein, welcoming promising young men and leaving them free to follow their own interests. A wealthy, cultured, and highly articulate man, fond of travel and much given to hospitality, he became interested in the speculative and cosmological aspects of biology, and many of his later publications concern these topics. He wrote no book but was the author of more than 100 papers.

BIBLIOGRAPHY

The most informative obituary notices are those of F. A. Freeth, in Biographical Memoirs of Fellows of the Royal Society, 3 (1957), 23–29, which includes a portrait and a complete bibliography; W. E. Garner, in Proceedings of the Chemical Society (1957), 362–366, with portrait; and C. F. Goodeve, in Nature, 179 (1957), 235–236.

W. V. Farrar

Donnan, Frederick George (1870-1956)

British chemist

Frederick George Donnan was a British chemist whose work in the second decade of the twentieth century established the existence of an electrochemical potential between a semipermeable membrane. The membrane allows an unequal distribution of ionic species to become established on either side of the membrane. In bacteria , this Donnan equilibrium has been demonstrated to exist across the outer membrane of Gramnegative bacteria, which separates the external environment from the periplasm . The energy derived from this ionic inequity is vital for the operation of the bacteria.

Donnan was born in Colombo, Ceylon (now known as Sri Lanka). He was educated at Queen's College in Belfast, Northern Ireland, at the University of Leipzig in Berlin, and at the University College, London. He taught at Liverpool University from 1904 until 1913, when he rejoined the faculty of University College as a Professor of Inorganic and Physical Chemistry. He remained there until his retirement in 1937.

In 1911, Donnan began his studies of the equilibrium between solutions separated by a semipermeable membrane that led to the establishment of the Donnan equilibrium. He also was involved in important studies in physical chemistry, which included the study of colloids and soap solutions, behavior of various gases, oxygen solubility, and the manufacture of nitric acid.

Of all his research achievements, Donnan's major accomplish was the theory of membrane equilibrium. In his productive research career, Donnan authored more than one hundred research papers.

See also Bacterial membranes and cell wall