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Johannes Thiele (chemist)
Encyclopedia
Friedrich Karl Johannes Thiele (May 13 1865 – April 17 1918) was a German
chemist
and a prominent professor at several universities, including those in Munich
and Strasbourg
. He developed many laboratory techniques related to isolation of organic compounds. In 1917 he described a device for the accurate determination of melting point
s, since named Thiele tube
after him.
Thiele was born in Ratibor, Prussia
, now Racibórz
, Poland
. Thiele studied mathematics
at the University of Breslau but later turned to chemistry, receiving his doctorate
from Halle
in 1890 . He taught at the University of Munich from 1893 to 1902 , when he was appointed professor of chemistry at Strasbourg
.
He developed the preparation of glyoxal bis(guanylhydrazone).
After Kekulé
's proposal for benzene structure
in 1865, he suggested a "Partial Valence Hypothesis", which concerned double
and triple carbon-carbon bonds with which he explains their particular reactivity. This led to the prediction of the resonance
that existed in benzene
in 1899 and proposed a resonance structure, by using a broken circle to represent the partial bonds. Later this problem was completely solved with the arrival of quantum theory
.
In 1899, Thiele was head of Organic Chemistry
at the Bavarian Academy of Sciences
in Munich
. With his associate Otto Holzinger, he synthesised an iminodibenzyl nucleus: two benzene rings attached together by a nitrogen atom and an ethylene bridge.
He discovered the condensation of ketone
s and aldehyde
s with cyclopentadiene
as a route to fulvene
s. He also recognized that these deeply colored species were related to but isomeric with benzene derivatives.
According to one of his students Heinrich Otto Wieland
, Thiele had a dislike of the chemistry of natural products.
Germans
The Germans are a Germanic ethnic group native to Central Europe. The English term Germans has referred to the German-speaking population of the Holy Roman Empire since the Late Middle Ages....
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...
and a prominent professor at several universities, including those in Munich
Munich
Munich The city's motto is "" . Before 2006, it was "Weltstadt mit Herz" . Its native name, , is derived from the Old High German Munichen, meaning "by the monks' place". The city's name derives from the monks of the Benedictine order who founded the city; hence the monk depicted on the city's coat...
and Strasbourg
Strasbourg
Strasbourg is the capital and principal city of the Alsace region in eastern France and is the official seat of the European Parliament. Located close to the border with Germany, it is the capital of the Bas-Rhin département. The city and the region of Alsace are historically German-speaking,...
. He developed many laboratory techniques related to isolation of organic compounds. In 1917 he described a device for the accurate determination of melting point
Melting point
The melting point of a solid is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at standard atmospheric pressure...
s, since named Thiele tube
Thiele tube
The Thiele tube, named after the German chemist Johannes Thiele, is a laboratory glassware designed to contain and heat an oil bath. Such a setup is commonly used in the determination of the melting point of a substance...
after him.
Thiele was born in Ratibor, Prussia
Prussia
Prussia was a German kingdom and historic state originating out of the Duchy of Prussia and the Margraviate of Brandenburg. For centuries, the House of Hohenzollern ruled Prussia, successfully expanding its size by way of an unusually well-organized and effective army. Prussia shaped the history...
, now Racibórz
Racibórz
Racibórz is a town in southern Poland with 60,218 inhabitants situated in the Silesian Voivodeship , previously in Katowice Voivodeship...
, Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
. Thiele studied mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
at the University of Breslau but later turned to chemistry, receiving his doctorate
Doctorate
A doctorate is an academic degree or professional degree that in most countries refers to a class of degrees which qualify the holder to teach in a specific field, A doctorate is an academic degree or professional degree that in most countries refers to a class of degrees which qualify the holder...
from Halle
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 1890 . He taught at the University of Munich from 1893 to 1902 , when he was appointed professor of chemistry at Strasbourg
Strasbourg
Strasbourg is the capital and principal city of the Alsace region in eastern France and is the official seat of the European Parliament. Located close to the border with Germany, it is the capital of the Bas-Rhin département. The city and the region of Alsace are historically German-speaking,...
.
He developed the preparation of glyoxal bis(guanylhydrazone).
After Kekulé
Friedrich August Kekulé von Stradonitz
Friedrich August Kekule von Stradonitz was a German organic chemist. From the 1850s until his death, Kekule was one of the most prominent chemists in Europe, especially in theoretical chemistry...
's proposal for benzene structure
Aromaticity
In organic chemistry, Aromaticity is a chemical property in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone. The earliest use of the term was in an article by August...
in 1865, he suggested a "Partial Valence Hypothesis", which concerned double
Covalent bond
A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....
and triple carbon-carbon bonds with which he explains their particular reactivity. This led to the prediction of the resonance
Resonance (chemistry)
In chemistry, resonance or mesomerism is a way of describing delocalized electrons within certain molecules or polyatomic ions where the bonding cannot be expressed by one single Lewis formula...
that existed in benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
in 1899 and proposed a resonance structure, by using a broken circle to represent the partial bonds. Later this problem was completely solved with the arrival of quantum theory
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
.
In 1899, Thiele was head of Organic Chemistry
Organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives...
at the Bavarian Academy of Sciences
Bavarian Academy of Sciences and Humanities
The Bavarian Academy of Sciences and Humanities is an independent public institution, located in Munich. It appoints scholars whose research has contributed considerably to the increase of knowledge within their subject...
in Munich
Munich
Munich The city's motto is "" . Before 2006, it was "Weltstadt mit Herz" . Its native name, , is derived from the Old High German Munichen, meaning "by the monks' place". The city's name derives from the monks of the Benedictine order who founded the city; hence the monk depicted on the city's coat...
. With his associate Otto Holzinger, he synthesised an iminodibenzyl nucleus: two benzene rings attached together by a nitrogen atom and an ethylene bridge.
He discovered the condensation of ketone
Ketone
In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...
s and aldehyde
Aldehyde
An aldehyde is an organic compound containing a formyl group. This functional group, with the structure R-CHO, consists of a carbonyl center bonded to hydrogen and an R group....
s with cyclopentadiene
Cyclopentadiene
Cyclopentadiene is an organic compound with the formula C5H6. This colorless liquid has a strong and unpleasant odor. At room temperature, this cyclic diene dimerizes over the course of hours to give dicyclopentadiene via a Diels–Alder reaction...
as a route to fulvene
Fulvene
Fulvene is one of several hydrocarbons with the same formula as benzene, C6H6. Fulvenes include the derivatives of this simple hydrocarbon, which itself is rarely encountered. Thiele is credited with discovering the scope of the reaction between cyclopentadiene and aldehydes and ketones that...
s. He also recognized that these deeply colored species were related to but isomeric with benzene derivatives.
According to one of his students Heinrich Otto Wieland
Heinrich Otto Wieland
Heinrich Otto Wieland was a German chemist. He won the 1927 Nobel Prize in Chemistry for his research into the bile acids. In 1901 Wieland received his doctorate at the University of Munich while studying under Johannes Thiele...
, Thiele had a dislike of the chemistry of natural products.