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Adolf Karl Ludwig Claus
Adolf Karl Ludwig Claus (6 June 1838 – 4 May 1900) was a German chemist. He is known for his structure of benzene proposed in 1867. Life Claus was born in 1838 in Kassel, Germany. Starting from 1850, he studied medicine in Marburg and later chemistry at the University of Marburg, with Hermann Kolbe. After spending a short time at the University of Berlin, he worked with Friedrich Wöhler at the University of Göttingen. He received his PhD in 1862, and in the same year changed his position and started working at the University of Freiburg. He completed his habilitation in 1866 and became assistant professor in the following year. With the retirement of Lambert Heinrich von Babo, Claus succeeded him as full professor. He held that position until his retirement due to health problems in 1900. Clause died in Horheim near Wutöschingen in the same year. Work Claus mostly worked in organic chemistry where his interests were very diverse and included alkaloids, aromatic substituti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kassel
Kassel (; in Germany, spelled Cassel until 1926) is a city on the Fulda River in northern Hesse, Germany. It is the administrative seat of the Regierungsbezirk Kassel and the district of the same name and had 201,048 inhabitants in December 2020. The former capital of the state of Hesse-Kassel has many palaces and parks, including the Bergpark Wilhelmshöhe, which is a UNESCO World Heritage Site. Kassel is also known for the '' documenta'' exhibitions of contemporary art. Kassel has a public university with 25,000 students (2018) and a multicultural population (39% of the citizens in 2017 had a migration background). History Kassel was first mentioned in 913 AD, as the place where two deeds were signed by King Conrad I. The place was called ''Chasella'' or ''Chassalla'' and was a fortification at a bridge crossing the Fulda river. There are several yet unproven assumptions of the name's origin. It could be derived from the ancient ''Castellum Cattorum'', a castle of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambert Heinrich Von Babo
Lambert Heinrich Joseph Anton Konrad Freiherr von Babo (November 25, 1818 – April 15, 1899) was a German chemist. Life Babo was the son of the agronomist Lambert Joseph von Babo and his first wife Karoline Ehrmann. The oenologist August Wilhelm von Babo was his half-brother. After graduating from high school Babo studied medicine at the Universities of Heidelberg and Munich and received a doctorate in 1842 from Heidelberg. In the following year he began studying chemistry under Justus von Liebig at Gießen receiving his habilitation in 1845 from Freiburg im Breisgau. On September 6, 1847 he married Elise Baumgärtner in Freiburg and had a daughter and two sons. He became a Privatdozent at the University of Freiburg außerordentlicher Professor in 1854 and ordentlicher Professor in 1859. As such, he was also appointed an expert for the Grand Ducal courts. Work Babo determined vapor pressure of water, called von Babo's law Von Babo's law (sometimes styled Babo's law) is a exp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1838 Births
Events January–March * January 10 – A fire destroys Lloyd's Coffee House and the Royal Exchange in London. * January 11 – At Morristown, New Jersey, Samuel Morse, Alfred Vail and Leonard Gale give the first public demonstration of Morse's new invention, the telegraph. * January 11 - A 7.5 earthquake strikes the Romanian district of Vrancea causing damage in Moldavia and Wallachia, killing 73 people. * January 21 – The first known report about the lowest temperature on Earth is made, indicating in Yakutsk. * February 6 – Boer explorer Piet Retief and 60 of his men are massacred by King Dingane kaSenzangakhona of the Zulu people, after Retief accepts an invitation to celebrate the signing of a treaty, and his men willingly disarm as a show of good faith. * February 17 – Weenen massacre: Zulu impis massacre about 532 Voortrekkers, Khoikhoi and Basuto around the site of Weenen in South Africa. * February 24 – U.S. Representatives William J. Graves of K ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 stereoisomers, which by definition have the same molecular formula and sequence of bonded atoms (constitution), but differ in structural formula (the three-dimensional orientations of their atoms in space). For this reason, it is also known as 3D chemistry—the prefix "stereo-" means "three-dimensionality". Stereochemistry spans the entire spectrum of organic, inorganic, biological, physical and especially supramolecular chemistry. Stereochemistry includes methods for determining and describing these relationships; the effect on the physical or biological properties these relationships impart upon the molecules in question, and the manner in which these relationships influence the reactivity of the molecules in question ( dynamic stereochemis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxime
In organic chemistry, an oxime is a organic compound belonging to the imines, with the general formula , where R is an organic side-chain and R’ may be hydrogen, forming an aldoxime, or another organic group, forming a ketoxime. O-substituted oximes form a closely related family of compounds. Amidoximes are oximes of amides () with general structure . Oximes are usually generated by the reaction of hydroxylamine with aldehydes () or ketones (). The term ''oxime'' dates back to the 19th century, a combination of the words ''oxygen'' and ''imine''. Structure and properties If the two side-chains on the central carbon are different from each other—either an aldoxime, or a ketoxime with two different "R" groups—the oxime can often have two different geometric stereoisomeric forms according to the ''E''/''Z'' configuration. An older terminology of ''syn'' and ''anti'' was used to identify especially aldoximes according to whether the R group was closer or further from the hy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isomers
In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. Isomers do not necessarily share similar chemical or physical properties. Two main forms of isomerism are structural or constitutional isomerism, in which ''bonds'' between the atoms differ; and stereoisomerism or spatial isomerism, in which the bonds are the same but the ''relative positions'' of the atoms differ. Isomeric relationships form a hierarchy. Two chemicals might be the same constitutional isomer, but upon deeper analysis be stereoisomers of each other. Two molecules that are the same stereoisomer as each other might be in different conformational forms or be different isotopologues. The depth of analysis depends on the field of study or the chemical and physical properties of interest. The English word "isomer" () is a back-form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of The American Chemical Society
The ''Journal of the American Chemical Society'' is a weekly peer-reviewed scientific journal that was established in 1879 by the American Chemical Society. The journal has absorbed two other publications in its history, the ''Journal of Analytical and Applied Chemistry'' (July 1893) and the ''American Chemical Journal'' (January 1914). It covers all fields of chemistry. Since 2021, the editor-in-chief is Erick M. Carreira (ETH Zurich). In 2014, the journal moved to a hybrid open access publishing model. Abstracting and indexing The journal is abstracted and indexed in Chemical Abstracts Service, Scopus, EBSCO databases, ProQuest databases, Index Medicus/MEDLINE/PubMed, and the Science Citation Index Expanded. According to the ''Journal Citation Reports'', the journal has a 2021 impact factor of 16.383. Editors-in-chief The following people are or have been editor-in-chief: * 1879–1880 – Hermann Endemann * 1880–1881 – Gideon E. Moore * 1881–1882 – Hermann Endemann ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prismane
Prismane or 'Ladenburg benzene' is a polycyclic hydrocarbon with the formula C6H6. It is an isomer of benzene, specifically a valence isomer. Prismane is far less stable than benzene. The carbon (and hydrogen) atoms of the prismane molecule are arranged in the shape of a six-atom triangular prism—this compound is the parent and simplest member of the prismanes class of molecules. Albert Ladenburg proposed this structure for the compound now known as benzene. The compound was not synthesized until 1973. History In the mid 19th century, investigators proposed several possible structures for benzene which were consistent with its empirical formula, C6H6, which had been determined by combustion analysis. The first, which was proposed by Kekulé in 1865, later proved to be closest to the true structure of benzene. This structure inspired several others to draw structures that were consistent with benzene's empirical formula; for example, Ladenburg proposed prismane, Dewar pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
August Kekulé
Friedrich August Kekulé, later Friedrich August Kekule von Stradonitz ( , ; 7 September 1829 – 13 July 1896), was a German organic chemist. From the 1850s until his death, Kekulé was one of the most prominent chemists in Europe, especially in theoretical chemistry. He was the principal founder of the theory of chemical structure and in particular the Kekulé structure of benzene. Name Kekulé never used his first given name; he was known throughout his life as August Kekulé. After he was ennobled by the Kaiser in 1895, he adopted the name August Kekule von Stradonitz, without the French acute accent over the second "e". The French accent had apparently been added to the name by Kekulé's father during the Napoleonic occupation of Hesse by France, to ensure that French-speaking people pronounced the third syllable. Early years The son of a civil servant, Kekulé was born in Darmstadt, the capital of the Grand Duchy of Hesse. After graduating from secondary school (the Grand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albert Ladenburg
Albert Ladenburg (July 2, 1842August 15, 1911) was a German chemist. Early life and education Ladenburg was a member of the well-known Jewish in Mannheim. He was educated at a Realgymnasium at Mannheim and then, after the age of 15, at the technical school of Karlsruhe, where he studied mathematics and modern languages. He then proceeded to the University of Heidelberg where he studied chemistry and physics with Robert Bunsen. He also studied physics in Berlin. He got his Ph.D. in Heidelberg. Academic career In 1873, Ladenburg went to Kiel as professor of chemistry and director of the laboratory, remaining there until 1889 when he went to the University of Breslau in the same capacity. He was made an honorary member of the Pharmaceutical Society of Great Britain in 1886 and received the Hanbury Medal for original research in chemistry in 1889. Ladenburg isolated hyoscine, also known as scopolamine for the first time in 1880. In 1900 Ladenburg founded the ''Chemische Gesells ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substitution Reaction
A substitution reaction (also known as single displacement reaction or single substitution reaction) is a chemical reaction during which one functional group in a chemical compound is replaced by another functional group. Substitution reactions are of prime importance in organic chemistry. Substitution reactions in organic chemistry are classified either as electrophilic or nucleophilic depending upon the reagent involved, whether a reactive intermediate involved in the reaction is a carbocation, a carbanion or a free radical, and whether the substrate is aliphatic or aromatic. Detailed understanding of a reaction type helps to predict the product outcome in a reaction. It also is helpful for optimizing a reaction with regard to variables such as temperature and choice of solvent. A good example of a substitution reaction is halogenation. When chlorine gas (Cl2) is irradiated, some of the molecules are split into two chlorine radicals (Cl•), whose free electrons are strongly n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkaloid
Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar structure may also be termed alkaloids. In addition to carbon, hydrogen and nitrogen, alkaloids may also contain oxygen, sulfur and, more rarely, other elements such as chlorine, bromine, and phosphorus.Chemical Encyclopedia: alkaloids xumuk.ru Alkaloids are produced by a large variety of organisms including , , Medicinal plant, plants, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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