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Julius Tröger
Julius Tröger (10 October 1862 – 29 July 1942) was a German chemist. Tröger studied at the University of Leipzig from 1882 till 1888. During his Ph.D. he synthesized in 1887 2,8-dimethyl-6''H'',12''H''-5,11-methanodibenzo- 'b'',''f''1,5]diazocine from p-toluidine, ''p''-toluidine and formaldehyde. This substance is now known as the Tröger's base. Because he was not able to give a structure of the new compound Johannes Wislicenus, the new director of the department, assigned a mediocre grade for Trögers thesis. It took another 48 years to confirm the structure of Tröger's base. In 1888 he started working at the Braunschweig University of Technology TU Braunschweig (, unofficially ''University of Braunschweig – Institute of Technology'') is the oldest ' (comparable to an institute of technology in the American system) in Germany. It was founded in 1745 as Collegium Carolinum and is a membe ... where he stayed until his retirement in 1928. Tröger died in Brunswick. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leipzig
Leipzig (, ; ; Upper Saxon: ; ) is the most populous city in the States of Germany, German state of Saxony. The city has a population of 628,718 inhabitants as of 2023. It is the List of cities in Germany by population, eighth-largest city in Germany and is part of the Central German Metropolitan Region. The name of the city is usually interpreted as a Slavic term meaning ''place of linden trees'', in line with many other Slavic placenames in the region. Leipzig is located about southwest of Berlin, in the southernmost part of the North German Plain (the Leipzig Bay), at the confluence of the White Elster and its tributaries Pleiße and Parthe. The Leipzig Riverside Forest, Europe's largest intra-city riparian forest, has developed along these rivers. Leipzig is at the centre of Neuseenland (''new lake district''). This district has Bodies of water in Leipzig, several artificial lakes created from former lignite Open-pit_mining, open-pit mines. Leipzig has been a trade city s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formaldehyde
Formaldehyde ( , ) (systematic name methanal) is an organic compound with the chemical formula and structure , more precisely . The compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde. It is stored as aqueous solutions (formalin), which consists mainly of the hydrate CH2(OH)2. It is the simplest of the aldehydes (). As a precursor to many other materials and chemical compounds, in 2006 the global production of formaldehyde was estimated at 12 million tons per year. It is mainly used in the production of industrial resins, e.g., for particle board and coatings. Formaldehyde also occurs naturally. It is derived from the degradation of serine, dimethylglycine, and lipids. Demethylases act by converting N-methyl groups to formaldehyde. Formaldehyde is classified as a group 1 carcinogen and can cause respiratory and skin irritation upon exposure. Forms Formaldehyde is more complicated than many simple carbon compounds in that i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leipzig University Alumni
Leipzig (, ; ; Upper Saxon: ; ) is the most populous city in the German state of Saxony. The city has a population of 628,718 inhabitants as of 2023. It is the eighth-largest city in Germany and is part of the Central German Metropolitan Region. The name of the city is usually interpreted as a Slavic term meaning ''place of linden trees'', in line with many other Slavic placenames in the region. Leipzig is located about southwest of Berlin, in the southernmost part of the North German Plain (the Leipzig Bay), at the confluence of the White Elster and its tributaries Pleiße and Parthe. The Leipzig Riverside Forest, Europe's largest intra-city riparian forest, has developed along these rivers. Leipzig is at the centre of Neuseenland (''new lake district''). This district has several artificial lakes created from former lignite open-pit mines. Leipzig has been a trade city since at least the time of the Holy Roman Empire. Via Regia and the Via Imperii, two importa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientists From Leipzig
A scientist is a person who researches to advance knowledge in an area of the natural sciences. In classical antiquity, there was no real ancient analog of a modern scientist. Instead, philosophers engaged in the philosophical study of nature called natural philosophy, a precursor of natural science. Though Thales ( 624–545 BC) was arguably the first scientist for describing how cosmic events may be seen as natural, not necessarily caused by gods,Frank N. Magill''The Ancient World: Dictionary of World Biography'', Volume 1 Routledge, 2003 it was not until the 19th century that the term ''scientist'' came into regular use after it was coined by the theologian, philosopher, and historian of science William Whewell in 1833. History The roles of "scientists", and their predecessors before the emergence of modern scientific disciplines, have evolved considerably over time. Scientists of different eras (and before them, natural philosophers, mathematicians, natur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1942 Deaths
The Uppsala Conflict Data Program project estimates this to be the deadliest year in human history in terms of conflict deaths, placing the death toll at 4.62 million. However, the Correlates of War estimates that the prior year, 1941, was the deadliest such year. Death toll estimates for both 1941 and 1942 range from 2.28 to 7.71 million each. Events Below, the events of World War II have the "WWII" prefix. January * January 1 – WWII: The Declaration by United Nations is signed by China, the United Kingdom, the United States, the Soviet Union, and 22 other nations, in which they agree "not to make any separate peace with the Axis powers". * January 5 – WWII: Two prisoners, British officer Airey Neave and Dutch officer Anthony Luteyn, escape from Colditz Castle in Germany. After travelling for three days, they reach the Swiss border. * January 7 – WWII: ** Battle of Slim River: Japanese forces of the 5th Division, supported by tanks, sweep through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1862 Births
Events January * January 1 – The United Kingdom annexes Lagos Island, in modern-day Nigeria. * January 6 – Second French intervention in Mexico, French intervention in Mexico: Second French Empire, French, Spanish and British forces arrive in Veracruz, Mexico. * January 16 – Hartley Colliery disaster in north-east England: 204 men are trapped and die underground when the only shaft becomes blocked. * January 30 – American Civil War: The first U.S. ironclad warship, , is launched in Brooklyn. * January 31 – Alvan Graham Clark makes the first observation of Sirius B, a white dwarf star, through an eighteen-inch telescope at Northwestern University in Illinois. February * February 1 – American Civil War: Julia Ward Howe's "Battle Hymn of the Republic" is published for the first time in the ''Atlantic Monthly''. * February 2 – The Dun Mountain Railway, first railway is opened in New Zealand, by the Dun Mountain Copper Mining Compan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johannes Wislicenus
Johannes Wislicenus (; 24 June 18355 December 1902) was a German chemist, most famous for his work in early stereochemistry. Biography The son of the radical Protestant theologian Gustav Wislicenus, Johannes was born on 24 June 1835 in Kleineichstedt (now part of Querfurt, Saxony-Anhalt) in Prussian Saxony, and entered University of Halle-Wittenberg in 1853. In October 1853 he immigrated to the United States 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 at the University of Halle. In 1860, he began lecturing at the University of Zürich, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P-toluidine
There are three isomers of toluidine, which are organic compounds discovered and named by James Sheridan Muspratt and August Wilhelm von Hofmann in 1845. These isomers are ''o''-toluidine, ''m''-toluidine, and ''p''-toluidine, with the prefixed letter abbreviating, respectively, ''ortho''; ''meta''; and ''para''. All three are aryl amines whose chemical structures are similar to aniline except that a methyl group is substituted onto the benzene ring. The difference between these three isomers is the position where the methyl group (–CH3) is bonded to the ring relative to the amino functional group (–NH2); see illustration of the chemical structures below. The chemical properties of the toluidines are quite similar to those of aniline, and toluidines have properties in common with other aromatic amines. Due to the amino group bonded to the aromatic ring, the toluidines are weakly basic. The toluidines are poorly soluble in pure water but dissolve well in acidic water due t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kingdom Of Saxony
The Kingdom of Saxony () was a German monarchy in Central Europe between 1806 and 1918, the successor of the Electorate of Saxony. It joined the Confederation of the Rhine after the dissolution of the Holy Roman Empire, later joining the German Confederation after Napoleon was defeated in 1815. From 1871, it was part of the German Empire. It became a Free state (polity)#Germany, free state of the Weimar Republic in 1918 after the end of World War I and the abdication of King Frederick Augustus III of Saxony, Frederick Augustus III. Its capital was Dresden, and its modern successor is the Saxony, Free State of Saxony. History Napoleonic era and the German Confederation Before 1806, Saxony was part of the Holy Roman Empire, a thousand-year-old entity that had become highly decentralised over the centuries. The rulers of the Electorate of Saxony of the House of Wettin had held the title of prince-elector, elector for several centuries. The Holy Roman Empire was dissolved in Augu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemist
A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of matter and its properties. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms. Chemists carefully measure substance proportions, chemical reaction rates, and other chemical properties. In Commonwealth English, pharmacists are often called chemists. Chemists use their knowledge to learn the composition and properties of unfamiliar substances, as well as to reproduce and synthesize large quantities of useful naturally occurring substances and create new artificial substances and useful processes. Chemists may specialize in any number of Chemistry#Subdisciplines, subdisciplines of chemistry. Materials science, Materials scientists and metallurgists sha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tröger's Base
Tröger's base is a white solid tetracyclic organic compound. Its chemical formula is . Tröger's base and its analogs are soluble in various organic solvents and strong acidic aqueous solutions due to their protonation. It is named after Julius Tröger, who first synthesized it in 1887. History Tröger's original research in 1887 failed to elaborate the exact structure of his new product, leading Johannes Wislicenus, the departmental director of the time, to assign a mediocre grade for Tröger's thesis. Though various possible structures had been drawn for Tröger's product, its correct structure remained as a mystery for 48 years, until the final elucidation in 1935 by Spielman. Structure and chirality The nitrogen inversion normally leads to a rapid equilibrium between the enantiomers of chiral amines, that prevents them showing any optical activity. The inversion can be stopped by conformational strain as Tröger's base has demonstrated that nitrogen is capable of forming a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
