Johannes Nicolaus Brønsted

Johannes Nicolaus Brønsted (Template:IPA; 22 February 1879 – 17 December 1947) was a Danish physical chemist who is best known for developing the Brønsted–Lowry acid–base theory; he developed the theory at the same time as (but independently of) Martin Lowry.<ref name=britannica>Template:Cite encyclopedia</ref>

Biography

Brønsted was born in Varde, Denmark on 22 February 1879. His mother died shortly after his birth, and his father died when Brønsted was 14 years old; he then moved to Copenhagen with his older sister and his stepmother.<ref>Template:Cite web</ref> In 1897, Brønsted began his studies as a chemical engineer at the Polytechnic Institute in Copenhagen. After his first degree, Brønsted changed fields and received his magister degree in chemistry in 1902 from the University of Copenhagen. In 1905, he became an assistant at the Chemical Institute and obtained his doctoral degree in 1908. In the same year, Brønsted became a professor of physical and inorganic chemistry at the University of Copenhagen.<ref name=bell-lecture/>

In 1929, Brønsted was a visiting professor at Yale University.<ref name="Oesper-chemed">Template:Cite journal</ref> His research gained worldwide recognition, resulting in four Nobel Prize nominations, a gold H. C. Ørsted Medal and being appointed as a fellow of the Royal Society and a member of the National Academy of Sciences.<ref name=britannica/><ref>Template:Cite web</ref>

Brønsted married Charlotte Warberg, whom he met during his first degree. The couple had four children.<ref>Template:Cite web</ref> In World War II, Brønsted's opposition to the Nazis led to his election to the Danish parliament in 1947, but he was too ill to take his seat and died shortly after the election.<ref name=britannica/>

Research

Early in his career, Brønsted studied chemical thermodynamics and later studied electrolyte solutions and carried out an extensive series of solubility measurements. These measurements led him to establish general laws which were later confirmed when the Debye–Hückel theory was proposed.<ref name="bell-nature">Template:Cite journal</ref><ref name="bell-lecture">Template:Cite journal</ref>

Brønsted is best known for his work on reaction kinetics, in particular acid–base reactions. In 1923, he recognized that acid–base reactions involved the transfer of a proton, from the acid (proton donor) to the base (proton acceptor).<ref>Template:Cite journal</ref> Almost simultaneously and independently, the British chemist Martin Lowry arrived at the same conclusion, thus the name Brønsted–Lowry acid–base theory.<ref>Template:Cite journal</ref> Also in 1923, Gilbert N. Lewis proposed an electronic theory of acid–base reactions, but both theories remain commonly used.<ref name=britannica/>

Later in his career, Brønsted kept studying reaction kinetics, with a special focus on reactions taking place in non-aqueous solutions. He also developed some work about the effect of molecular size on the thermodynamical properties of hydrocarbons, polymers and colloids.<ref name=bell-nature/> He also worked with the Nobel prize winner George de Hevesy on isotope separation by fractional distillation.<ref>Template:Cite journal</ref>