|
Isomenthone
Menthone is a monoterpene with a minty flavor that occurs naturally in a number of essential oils. ''l''-Menthone (or (2''S'',5''R'')-''trans''-2-isopropyl-5-methylcyclohexanone), shown at right, is the most abundant in nature of the four possible stereoisomers. It is structurally related to menthol, which has a secondary alcohol in place of the carbonyl. Menthone is used in flavoring, perfume and cosmetics for its characteristic aromatic and minty odor. Occurrence Menthone is a constituent of the essential oils of pennyroyal, peppermint, ''Mentha arvensis'', ''Pelargonium'' geraniums, and others. In most essential oils, it is a minor compound; it was first synthesized by oxidation of menthol in 1881 before it was found in essential oils in 1891. Structure and preparation 2-Isopropyl-5-methylcyclohexanone has two asymmetric carbon centers, meaning that it can have four different stereoisomers: (2''S'',5''S''), (2''R'',5''S''), (2''S'',5''R'') and (2''R'',5''R''). The ''S'','' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terpene
Terpenes () are a class of natural products consisting of compounds with the formula (C5H8)n for n > 1. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predominantly by plants, particularly conifers. Terpenes are further classified by the number of carbons: monoterpenes (C10), sesquiterpenes (C15), diterpenes (C20), as examples. The terpene alpha-pinene, is a major component of the common solvent, turpentine. History and terminology The term ''terpene'' was coined in 1866 by the German chemist August Kekulé to denote all hydrocarbons having the empirical formula C10H16, of which camphene was one. Previously, many hydrocarbons having the empirical formula C10H16 had been called "camphene", but many other hydrocarbons of the same composition had had different names. Kekulé coined the term "terpene" in order to reduce the confusion. The name "terpene" is a shortened form of "terpentine", an obsolete spelling of "turpentine". Although sometimes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herbert Charles Brown
Herbert Charles Brown (May 22, 1912 – December 19, 2004) was an American chemist and recipient of the 1979 Nobel Prize in Chemistry for his work with organoboranes. Life and career Brown was born Herbert Brovarnik in London, to Ukrainian Jewish immigrants from Zhitomir, Pearl (''née'' Gorinstein) and Charles Brovarnik, a hardware store manager and carpenter. His family moved to Chicago in June 1914, when he was two years old. Brown attended Crane Junior College in Chicago, where he met Sarah Baylen, whom he would later marry. The college was under threat of closing, and Brown and Baylen transferred to Wright Junior College. In 1935 he left Wright Junior College and that autumn entered the University of Chicago, completed two years of studies in three quarters, and earned a B.S. in 1936. That same year, he became a naturalized United States citizen. On February 6, 1937, Brown married Baylen, the person he credits with making him interested in hydrides of boron, a topic re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoterpenes
Monoterpenes are a class of terpenes that consist of two isoprene units and have the molecular formula C10H16. Monoterpenes may be linear (acyclic) or contain rings (monocyclic and bicyclic). Modified terpenes, such as those containing oxygen functionality or missing a methyl group, are called monoterpenoids. Monoterpenes and monoterpenoids are diverse. They have relevance to the pharmaceutical, cosmetic, agricultural, and food industries. Biosynthesis Monoterpenes are derived biosynthetically from units of isopentenyl pyrophosphate, which is formed from acetyl-CoA via the intermediacy of mevalonic acid in the HMG-CoA reductase pathway. An alternative, unrelated biosynthesis pathway of IPP is known in some bacterial groups and the plastids of plants, the so-called MEP-(2-methyl-D-erythritol-4-phosphate) pathway, which is initiated from Pentose, C5 sugars. In both pathways, IPP is isomerized to DMAPP by the enzyme isopentenyl pyrophosphate isomerase. Geranyl pyrophosphate is the pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfume Ingredients
Perfume (, ; french: parfum) is a mixture of fragrant essential oils or aroma compounds (fragrances), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agreeable scent. The 1939 Nobel Laureate for Chemistry, Leopold Ružička stated in 1945 that "right from the earliest days of scientific chemistry up to the present time, perfumes have substantially contributed to the development of organic chemistry as regards methods, systematic classification, and theory." Ancient texts and archaeological excavations show the use of perfumes in some of the earliest human civilizations. Modern perfumery began in the late 19th century with the commercial synthesis of aroma compounds such as vanillin or coumarin, which allowed for the composition of perfumes with smells previously unattainable solely from natural aromatics. History The word ''perfume'' derives from the Latin ''perfumare'', meaning "to smoke through" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ketones
In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bond C=O). The simplest ketone is acetone (where R and R' is methyl), with the formula . Many ketones are of great importance in biology and in industry. Examples include many sugars (ketoses), many steroids (e.g., testosterone), and the solvent acetone. Nomenclature and etymology The word ''ketone'' is derived from ''Aketon'', an old German word for ''acetone''. According to the rules of IUPAC nomenclature, ketone names are derived by changing the suffix ''-ane'' of the parent alkane to ''-anone''. Typically, the position of the carbonyl group is denoted by a number, but traditional nonsystematic names are still generally used for the most important ketones, for example acetone and benzophenone. These nonsystematic names are considered ret ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cooling Flavors
Cooling is removal of heat, usually resulting in a lower temperature and/or phase change. Temperature lowering achieved by any other means may also be called cooling.ASHRAE Terminology, https://www.ashrae.org/technical-resources/free-resources/ashrae-terminology The transfer of thermal energy may occur via thermal radiation, heat conduction or convection. Examples can be as simple as reducing temperature of a coffee. Devices *Coolant *Cooling towers, as used in large industrial plants and power stations * Daytime passive radiative cooler *Evaporative cooler *Heat exchanger *Heat pipe *Heat sink * HVAC (Heating, Ventilation and Air Conditioning) * Intercooler *Radiative cooling in Heat shields * Radiators in automobiles *Pumpable ice technology *Thermoelectric cooling *Vortex tube The vortex tube, also known as the Ranque-Hilsch vortex tube, is a mechanical device that separates a compressed gas into hot and cold streams. The gas emerging from the hot end can reach temperatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flavors
Flavor or flavour is either the sensory perception of taste or smell, or a flavoring in food that produces such perception. Flavor or flavour may also refer to: Science *Flavors (programming language), an early object-oriented extension to Lisp * Flavour (particle physics), a quantum number of elementary particles related to their weak interactions *Flavor of Linux, another term for any particular Linux distribution; by extension, "flavor" can be applied to any program or other computer code that exists in more than one current variant at the same time Film and TV * ''Flavors'' (film), romantic comedy concerning Asian-Indian immigrants in America Music Artists and bands *Flavor Flav (born 1959), former rap/hip-hop promoter and current reality television actor *Flavour N'abania (born 1983), Nigerian singer-songwriter * Flavor (band), minor hit with "Sally Had A Party" in 1968 Albums * ''Flavours'' (album), 1975 album by The Guess Who * ''Flavors'' (album), by American R&B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tautomer
Tautomers () are structural isomers (constitutional isomers) of chemical compounds that readily interconvert. The chemical reaction interconverting the two is called tautomerization. This conversion commonly results from the relocation of a hydrogen atom within the compound. The phenomenon of tautomerization is called tautomerism, also called desmotropism. Tautomerism is for example relevant to the behavior of amino acids and nucleic acids, two of the fundamental building blocks of life. Care should be taken not to confuse tautomers with depictions of "contributing structures" in chemical resonance. Tautomers are distinct chemical species that can be distinguished by their differing atomic connectivities, molecular geometries, and physicochemical and spectroscopic properties, whereas resonance forms are merely alternative Lewis structure (valence bond theory) depictions of a single chemical species, whose true structure is best described as the "average" of the idealized, hypothe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liebigs Annalen
''Justus Liebigs Annalen der Chemie'' (often cited as just ''Liebigs Annalen'') was one of the oldest and historically most important journals in the field of organic chemistry worldwide. It was established in 1832 and edited by Justus von Liebig with Friedrich Wöhler and others until Liebig's death in 1873. In 1997 the journal merged with ''Recueil des Travaux Chimiques des Pays-Bas'' to form ''Liebigs Annalen/Recueil''. In 1998 it was absorbed by ''European Journal of Organic Chemistry'' by merger of a number of other national European chemistry journals. Title history * ''Annalen der Pharmacie'', 1832–1839 * ''Annalen der Chemie und Pharmacie'', 1840–1873 (, CODEN JLACBF) * ''Justus Liebig's Annalen der Chemie und Pharmacie'', 1873–1874 (, CODEN JLACBF) * ''Justus Liebig's Annalen der Chemie'', 1874–1944 & 1947–1978 (, CODEN JLACBF) * ''Liebigs Annalen der Chemie'', 1979–1994 (, CODEN LACHDL) * ''Liebigs Annalen'', 1995–1996 (, CODEN LANAEM) * ''Liebi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Rotation
Optical rotation, also known as polarization rotation or circular birefringence, is the rotation of the orientation of the plane of polarization about the optical axis of linearly polarized light as it travels through certain materials. Circular birefringence and circular dichroism are the manifestations of optical activity. Optical activity occurs only in chiral materials, those lacking microscopic mirror symmetry. Unlike other sources of birefringence which alter a beam's state of polarization, optical activity can be observed in fluids. This can include gases or solutions of chiral molecules such as sugars, molecules with helical secondary structure such as some proteins, and also chiral liquid crystals. It can also be observed in chiral solids such as certain crystals with a rotation between adjacent crystal planes (such as quartz) or metamaterials. When looking at the source of light, the rotation of the plane of polarization may be either to the right (dextrorotator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfuric Acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formula . It is a colorless, odorless and viscous liquid that is miscible with water. Pure sulfuric acid does not exist naturally on Earth due to its strong affinity to water vapor; it is hygroscopic and readily absorbs water vapor from the air. Concentrated sulfuric acid is highly corrosive towards other materials, from rocks to metals, since it is an oxidant with powerful dehydrating properties. Phosphorus pentoxide is a notable exception in that it is not dehydrated by sulfuric acid, but to the contrary dehydrates sulfuric acid to sulfur trioxide. Upon addition of sulfuric acid to water, a considerable amount of heat is released; thus the reverse procedure of adding water to the acid should not be performed since the heat released may boi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernst Beckmann
Ernst Otto Beckmann (July 4, 1853 – July 12, 1923) was a German pharmacist and chemist who is remembered for his invention of the Beckmann differential thermometer and for his discovery of the Beckmann rearrangement. Scientific work Ernst Otto Beckmann was born in Solingen, Germany on July 4, 1853, to a family headed by Johannes Friedrich Wilhelm Beckmann, a manufacturer. The elder Beckmann's factory produced mineral dyes, pigments, abrasives, and polishing material, and it was there that the younger Beckmann conducted his early chemical experiments. At the age of 17, Beckmann was persuaded by his father to study pharmacy instead of chemistry, and so in 1870 an apprenticeship was arranged in Elberfeld. However, Beckmann did not enjoy the working conditions and returned home, to his father's disappointment. Told that a chemical career would be difficult if could not handle an apprenticeship in pharmacy, Beckmann then returned to Elberfeld to finish his work. He also worked at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.svg "Click for more on -> Optical Rotation")
