Johannes Wislicenus (24 June 1835 – 5 December 1902) was a German

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe th ...

, most famous for his work in early

stereochemistry Stereochemistry, a subdiscipline of chemistry, involves the study of the relative spatial arrangement of atoms that form the structure of molecules and their manipulation. The study of stereochemistry focuses on the relationships between stereois ...

Biography

The son of the radical Protestant theologian Gustav Wislicenus, Johannes was born on 24 June 1835 in Kleineichstedt (now part of

Querfurt Querfurt () is a town in the Saalekreis district, or ''Kreis'', in southern Saxony-Anhalt, Germany. It is located in a fertile area on the Querne, west from Merseburg. In 2020, the town had a population of 10,454. The town Querfurt consists of Q ...

Saxony-Anhalt Saxony-Anhalt (german: Sachsen-Anhalt ; nds, Sassen-Anholt) is a state of Germany, bordering the states of Brandenburg, Saxony, Thuringia and Lower Saxony. It covers an area of and has a population of 2.18 million inhabitants, making it the ...

) in

Prussian Saxony The Province of Saxony (german: link=no, Provinz Sachsen), also known as Prussian Saxony () was a province of the Kingdom of Prussia and later the Free State of Prussia from 1816 until 1944. Its capital was Magdeburg. It was formed by the merge ...

, and entered

Halle University Martin Luther University of Halle-Wittenberg (german: Martin-Luther-Universität Halle-Wittenberg), also referred to as MLU, is a public, research-oriented university in the cities of Halle and Wittenberg and the largest and oldest university i ...

in 1853. In October 1853 he emigrated to the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

with his family. For a brief time he acted as assistant to Harvard chemist

Eben Horsford Eben Norton Horsford (27 July 1818 – 1 January 1893) was an American scientist who taught agricultural chemistry in the Lawrence Scientific School at Harvard from 1847 to 1863. Later he was known for his reformulation of baking powder, his int ...

, and in 1855 was appointed lecturer at the Mechanics' Institute in New York. Returning to Europe in 1856, he continued to study chemistry with Wilhelm Heinrich Heintz at the University of Halle. In 1860, he began lecturing at the

University of Zürich The University of Zürich (UZH, german: Universität Zürich) is a public research university located in the city of Zürich, Switzerland. It is the largest university in Switzerland, with its 28,000 enrolled students. It was founded in 1833 f ...

, and at the Swiss Polytechnical Institute and by 1868 he was Professor of Chemistry at the university. In 1870, he was chosen to succeed Georg Staedeler as Professor of General Chemistry at the Swiss Polytechnical Institute in Zürich, retaining also the position of full professor at the University of Zürich. In 1872, he succeeded

Adolph Strecker Adolph Strecker (October 21, 1822 – November 7, 1871) was a German chemist who is remembered primarily for his work with amino acids. Life and work Strecker was born in Darmstadt, the son of Friedrich Ludwig Strecker, an archivist working for ...

in the chair of chemistry at

University of Würzburg The Julius Maximilian University of Würzburg (also referred to as the University of Würzburg, in German ''Julius-Maximilians-Universität Würzburg'') is a public research university in Würzburg, Germany. The University of Würzburg is one of ...

, and in 1885, he succeeded

Hermann Kolbe Adolph Wilhelm Hermann Kolbe (27 September 1818 – 25 November 1884) was a major contributor to the birth of modern organic chemistry. He was a professor at Marburg and Leipzig. Kolbe was the first to apply the term synthesis in a chemical cont ...

as Professor of Chemistry at the

University of Leipzig Leipzig University (german: Universität Leipzig), in Leipzig in Saxony, Germany, is one of the world's oldest universities and the second-oldest university (by consecutive years of existence) in Germany. The university was founded on 2 Decemb ...

, where he died on 6 December 1902.

Research

By the late 1860s, Wislicenus devoted his research to organic chemistry. His work on the isomeric lactic acids from 1868 to 1872 resulted in the discovery of two substances with different physical properties but with an identical

chemical structure A chemical structure determination includes a chemist's specifying the molecular geometry and, when feasible and necessary, the electronic structure of the target molecule or other solid. Molecular geometry refers to the spatial arrangement of at ...

. He called this difference "geometrical isomerism". He would later promote J. H. van't Hoff's theory of the tetrahedral carbon atom, believing that it, together with the supposition that there are "specially directed forces, the affinity-energies", which determine the relative position of atoms in the

molecule A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...

, afforded a method by which the spatial arrangement of atoms in particular cases may be ascertained by experiment. While at Würzburg, Wislicenus developed the use of ethyl aceto acetate in organic synthesis. However, he was also active in inorganic chemistry, finding a reaction for the production of sodium azide. He was the first to prepare

cyclopentane Cyclopentane (also called C pentane) is a highly flammable alicyclic hydrocarbon with chemical formula C5H10 and CAS number 287-92-3, consisting of a ring of five carbon atoms each bonded with two hydrogen atoms above and below the plane. It occur ...

in 1893J. Wislicenus and W. Hentschel (1893
"Der Pentamethenylalkohol und seine Derivate"
(Cyclopentanol and its derivatives), ''Annalen der Chemie'', 275 : 322-330; see especially pages 327-330. Wislicenus prepared cyclopentane from cyclopentanone ("Ketopentamethen"), which is prepared by heating calcium adipate.

Awards

In 1898 Wislicenus was awarded the

Davy Medal The Davy Medal is awarded by the Royal Society of London "for an outstandingly important recent discovery in any branch of chemistry". Named after Humphry Davy, the medal is awarded with a monetary gift, initially of £1000 (currently £2000). H ...

by the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

London London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...

Notes

References

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Biography

Research

Awards

Notes

References

Further reading