Johannes Wislicenus
Encyclopedia
Johannes Wislicenus was a German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
chemist
Chemist
A chemist is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties such as density and acidity. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms...
, most famous for his work in early stereochemistry
Stereochemistry
Stereochemistry, a subdiscipline of chemistry, involves the study of the relative spatial arrangement of atoms within molecules. An important branch of stereochemistry is the study of chiral molecules....
.
Biography
The son of the radical Protestant theologian Gustav WislicenusGustav Adolf Wislicenus
Gustav Adolf Wislicenus was a German theologian, one of the leaders of the Free Congregations.-Biography:...
, Johannes was born in Kleineichstedt
Querfurt
Querfurt a town in Saalekreis district in the south of Saxony-Anhalt, Germany, situated in a fertile area on the Querne, west from Merseburg, on a branch line from Oberroblingen. Pop. 12,935 .-History:...
(now part of Querfurt
Querfurt
Querfurt a town in Saalekreis district in the south of Saxony-Anhalt, Germany, situated in a fertile area on the Querne, west from Merseburg, on a branch line from Oberroblingen. Pop. 12,935 .-History:...
, Saxony-Anhalt
Saxony-Anhalt
Saxony-Anhalt is a landlocked state of Germany. Its capital is Magdeburg and it is surrounded by the German states of Lower Saxony, Brandenburg, Saxony, and Thuringia.Saxony-Anhalt covers an area of...
) in Prussian Saxony, and entered Halle University
University of Halle-Wittenberg
The Martin Luther University of Halle-Wittenberg , also referred to as MLU, is a public, research-oriented university in the cities of Halle and Wittenberg within Saxony-Anhalt, Germany...
in 1853. In October 1853 he emigrated to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
with his family. For a brief time he acted as assistant to Harvard chemist Eben Horsford, 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
Wilhelm Heinrich Heintz
Wilhelm Heinrich Heintz was a German structural chemist who earned his PhD at Berlin in 1844 under Heinrich Rose.He was one of six founding members of the Deutsche Physikalische Gesellschaft and the only chemist....
at the University of Halle. In 1860, he began lecturing at the University of Zürich
University of Zurich
The University of Zurich , located in the city of Zurich, is the largest university in Switzerland, with over 25,000 students. It was founded in 1833 from the existing colleges of theology, law, medicine and a new faculty of philosophy....
, and at the Swiss Polytechnical Institute
ETH Zurich
The Swiss Federal Institute of Technology Zurich or ETH Zürich is an engineering, science, technology, mathematics and management university in the City of Zurich, Switzerland....
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
Adolph Strecker was a German chemist who is remembered primarily for his work with amino acids.- Life and work :...
in the chair of chemistry at University of Würzburg
University of Würzburg
The University of Würzburg is a university in Würzburg, Germany, founded in 1402. The university is a member of the distinguished Coimbra Group.-Name:...
, and in 1885, he succeeded Hermann Kolbe as Professor of Chemistry at the University of Leipzig
University of Leipzig
The University of Leipzig , located in Leipzig in the Free State of Saxony, Germany, is one of the oldest universities in the world and the second-oldest university in Germany...
, where he died in 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 structureChemical structure
A chemical structure includes molecular geometry, electronic structure and crystal structure of molecules. Molecular geometry refers to the spatial arrangement of atoms in a molecule and the chemical bonds that hold the atoms together. Molecular geometry can range from the very simple, such as...
. 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
Molecule
A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...
, 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.