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August Wilhelm Von Hofmann
August Wilhelm von Hofmann (8 April 18185 May 1892) was a German chemist who made considerable contributions to organic chemistry. His research on aniline helped lay the basis of the aniline-dye industry, and his research on coal tar laid the groundwork for his student Charles Mansfield's practical methods for extracting benzene and toluene and converting them into nitro compounds and amines. Hofmann's discoveries include formaldehyde, hydrazobenzene, the isonitriles, and allyl alcohol. He prepared three ethylamines and tetraethylammonium compounds and established their structural relationship to ammonia. After studying under Justus von Liebig at the University of Giessen, Hofmann became the first director of the Royal College of Chemistry, now part of Imperial College London, in 1845. In 1865 he returned to Germany to accept a position at the University of Berlin as a teacher and researcher. After his return he co-founded the German Chemical Society (''Deutsche Chemis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giessen
Giessen, spelled in German (), is a town in the Germany, German States of Germany, state () of Hesse, capital of both the Giessen (district), district of Giessen and the Giessen (region), administrative region of Giessen. The population is approximately 90,000, with roughly 37,000 university students. The name comes from ''Giezzen'', as it was first referred to in 1197, which refers to the position of the town between several rivers, lakes and streams. The largest river in Giessen is the Lahn, which divides the town in two parts (west and east), roughly north of Frankfurt am Main. Giessen is also home to the University of Giessen. In 1969, the town hosted the ninth ''Hessentag'' state festival. History Giessen came into being as a moated castle in 1152 built by Count Wilhelm von Gleiberg, although the history of the community in the northeast and in today's suburb called "Wieseck" dates back to 775. The town became part of Hesse-Marburg in 1567, passing to Landgraviate of Hess ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Max Le Blanc
Max Julius Louis Le Blanc (1865 – 1943) was a German physical chemist who worked in the field of electrochemistry, writing an influential textbook in 1895 on the subject which went through several editions. He was a professor at the Technical University of Karlsruhe, later at the Wilhelm Ostwald Institute at Leipzig. He is best known for inventing the hydrogen electrode used for pH measurements. In 1933 he was a signatory to the Vow of allegiance of the Professors of the German Universities and High-Schools to Adolf Hitler and the National Socialistic State. Life and work Le Blanc was born on 26 May 1865 in Barciany, Barten, Kingdom of Prussia to builder Louis and his wife Marie Kickton and after studying at the Gymnasium in Kętrzyn, Rastenburg, he went to the universities at Tübingen and Berlin. His doctoral work of 1888 was on organic chemistry under August Wilhelm von Hofmann. He however moved to physical chemistry and worked under Wilhelm Ostwald at Leipzig from 1891. He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coal Tar
Coal tar is a thick dark liquid which is a by-product of the production of coke and coal gas from coal. It is a type of creosote. It has both medical and industrial uses. Medicinally it is a topical medication applied to skin to treat psoriasis and seborrheic dermatitis ( dandruff). It may be used in combination with ultraviolet light therapy. Industrially it is a railroad tie preservative and used in the surfacing of roads. Coal tar was listed as a known human carcinogen in the first Report on Carcinogens from the U.S. Federal Government, issued in 1980. Coal tar was discovered circa 1665 and used for medical purposes as early as the 1800s. Circa 1850, the discovery that it could be used as the main raw material for the synthesis of dyes engendered an entire industry. It is on the World Health Organization's List of Essential Medicines. Coal tar is available as a generic medication and over the counter. Side effects include skin irritation, sun sensitivity, aller ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aniline
Aniline (From , meaning ' indigo shrub', and ''-ine'' indicating a derived substance) is an organic compound with the formula . Consisting of a phenyl group () attached to an amino group (), aniline is the simplest aromatic amine. It is an industrially significant commodity chemical, as well as a versatile starting material for fine chemical synthesis. Its main use is in the manufacture of precursors to polyurethane, dyes, and other industrial chemicals. Like most volatile amines, it has the odor of rotten fish. It ignites readily, burning with a smoky flame characteristic of aromatic compounds. It is toxic to humans. Relative to benzene, aniline is "electron-rich". It thus participates more rapidly in electrophilic aromatic substitution reactions. Likewise, it is also prone to oxidation: while freshly purified aniline is an almost colorless oil, exposure to air results in gradual darkening to yellow or red, due to the formation of strongly colored, oxidized impurities. Ani ... [...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] |
Albert Medal (Royal Society Of Arts)
The Albert Medal of the Royal Society of Arts (RSA) was instituted in 1864 as a memorial to Prince Albert, who had been President of the Society for 18 years. It was first awarded in 1864 for "distinguished merit in promoting Arts, Manufactures and Commerce". In presenting the Medal, the Society now looks to acknowledge individuals, organizations and groups that lead progress and create positive change within contemporary society in areas that are linked closely to the Society's broad agenda. Through the Albert Medal, the Society acknowledges the creativity and innovation of those that work to tackle some of the world's intractable problems. Each year, the RSA identifies issues by asking the Society's Fellowship to suggest problems and subjects linked to the Society's programme. These proposals are reviewed and recommendations made to the Trustees and Council, who are responsible for selecting one upon which the Fellowship will be asked to nominate worthy recipients. Full list ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Faraday Lectureship Prize
The Faraday Lectureship Prize, previously known simply as the Faraday Lectureship, is awarded once every two years (approximately) by the Royal Society of Chemistry for "exceptional contributions to physical or theoretical chemistry".. Named after Michael Faraday, the first Faraday Lecture was given in 1869, two years after Faraday's death, by Jean-Baptiste Dumas Jean Baptiste André Dumas (; 14 July 180010 April 1884) was a French chemist, best known for his works on organic analysis and synthesis, as well as the determination of atomic weights (relative atomic masses) and molecular weights by measuri ..... As of 2009, the prize was worth £5000, with the recipient also receiving a medal and a certificate. As the name suggests, the recipient also gives a public lecture describing his or her work. Winners SourceRSC * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * See also * L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copley Medal
The Copley Medal is the most prestigious award of the Royal Society of the United Kingdom, conferred "for sustained, outstanding achievements in any field of science". The award alternates between the physical sciences or mathematics and the biological sciences. It is arguably the highest United Kingdom, British and Commonwealth of Nations, Commonwealth award for scientific achievement, and has often been included among the most distinguished international scientific awards. Given annually, the medal is the oldest Royal Society medal awarded and the oldest surviving scientific award in the world, having first been given in 1731 to Stephen Gray (scientist), Stephen Gray, for "his new Electrical Experiments: – as an encouragement to him for the readiness he has always shown in obliging the Society with his discoveries and improvements in this part of Natural Knowledge". The medal is made of silver-gilt and awarded with a £25,000 prize. It is awarded to "senior scientists" irres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Medal
The Royal Medal, also known as The Queen's Medal and The King's Medal (depending on the gender of the monarch at the time of the award), is a silver-gilt medal, of which three are awarded each year by the Royal Society. Two are given for "the most important contributions to the advancement of natural knowledge," and one for "distinguished contributions in the applied sciences", all of which are done within the Commonwealth of Nations. Background The award was created by George IV and awarded first during 1826. Initially there were two medals awarded, both for the most important discovery within the year previous, a time period which was lengthened to five years and then shortened to three. The format was endorsed by William IV and Victoria, who had the conditions changed during 1837 so that mathematics was a subject for which a Royal Medal could be awarded, albeit only every third year. The conditions were changed again during 1850 so that: ... the Royal Medals in each year sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ball-and-stick Model
In chemistry, the ball-and-stick model is a molecular model of a chemical substance which displays both the Molecular geometry, three-dimensional position of the atoms and the chemical bond, bonds between them. The atoms are typically represented by sphere (geometry), spheres, connected by rods which represent the bonds. Double bond, Double and triple bonds are usually represented by two or three curved rods, respectively, or alternately by correctly positioned sticks for the sigma bond, sigma and pi bonds. In a good model, the angles between the rods should be the same as the Bond angle, angles between the bonds, and the distances between the centers of the spheres should be proportional to the distances between the corresponding atomic nucleus, atomic nuclei. The chemical element of each atom is often indicated by the sphere's color. In a ball-and-stick model, the radius of the spheres is usually much smaller than the rod lengths, in order to provide a clearer view of the atoms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hofmann–Martius Rearrangement
The Hofmann–Martius rearrangement in organic chemistry is a rearrangement reaction converting an N-alkylated aniline to the corresponding ortho and / or para aryl-alkylated aniline. The reaction requires heat, and the catalyst is an acid like hydrochloric acid. : When the catalyst is a metal halide the reaction is also called the Reilly–Hickinbottom rearrangement (named after Wilfred Hickinbottom and Joseph Reilly). The reaction is also known to work for aryl ethers and two conceptually related reactions are the Fries rearrangement and the Fischer–Hepp rearrangement. Its reaction mechanism centers around dissociation of the reactant with the positively charged organic residue R attacking the aniline ring in a Friedel–Crafts alkylation. In one study this rearrangement was applied to a 3-N(CH3)(C6H5)-2-oxindole:heating 1 in toluene at 80 °C gives 30% 2-o (ortho) and 37% 2-p (para) : The reaction is named after German chemists August Wilhelm von Hofmann and Carl Alex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hofmann–Löffler Reaction
In organic chemistry, the Hofmann–Löffler reaction (also referred to as Hofmann–Löffler–Freytag reaction, Löffler–Freytag reaction, Löffler–Hofmann reaction, as well as Löffler's method) is a cyclization reaction with remote C–H functionalization. In the reaction, thermal or photochemical decomposition of ''N''-halogenated amine 1 in the presence of a strong acid (concentrated sulfuric acid or concentrated CF3CO2H, CF3CO2H) generates a nitrogen radical intermediate. The radical then abstracts an intramolecular hydrogen atom to give a cyclic amine 2 (pyrrolidine or, in some cases, piperidine). History In 1878, the structure of piperidine was still unknown, and August Wilhelm von Hofmann, A. W. Hofmann believed it unsaturated. Following standard analytical technique, Hofmann added hydrogen chloride or bromine to it in an attempt to induce hydrohalogenation. Instead, he produced ''N''-haloamines and ''N''-haloamides, whose reactions under acidic and basic cond ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
