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Ethanethiol
Ethanethiol, commonly known as ethyl mercaptan, is an organosulfur compound with the formula CH3CH2SH. It is a colorless liquid with a distinct odor. Abbreviated EtSH, it consists of an ethyl group (Et), CH3CH2, attached to a thiol group, SH. Its structure parallels that of ethanol, but with sulfur in place of oxygen. The odor of EtSH is infamous. Ethanethiol is more volatile than ethanol due to a diminished ability to engage in hydrogen bonding. Ethanethiol is toxic in high concentrations. It occurs naturally as a minor component of petroleum, and may be added to otherwise odorless gaseous products such as liquefied petroleum gas (LPG) to help warn of gas leaks. At these concentrations, ethanethiol is not harmful. Preparation Ethanethiol is prepared by the reaction of ethylene with hydrogen sulfide in the presence of various catalysts. It is also prepared commercially by the reaction of ethanol with hydrogen sulfide gas over an acidic solid catalyst, such as alumina. Historic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanethiol
Methanethiol (also known as methyl mercaptan) is an organosulfur compound with the chemical formula . It is a colorless gas with a distinctive putrid smell. In small amounts, it is pervasive in nature and found in certain foods, such as some nuts and cheese. It contributes to many odors including the emissions from pulp mills, bad breath, and flatus. Methanethiol is the simplest thiol and is sometimes abbreviated as MeSH. It is flammable. Structure and reactions The molecule is tetrahedral at the carbon atom, like methanol. It is a weak acid, with a p''K''a of ~10.4, but is about a hundred thousand times more acidic than methanol. The colorless salt can be obtained by treatment with sodium methoxide: :CH3SH + CH3ONa → CH3SNa + CH3OH The thiolate anion in sodium methanethiolate is a strong nucleophile. It can be oxidized to dimethyl disulfide: :2CH3SH + → CH3SSCH3 + H2O Further oxidation takes the disulfide to two molecules of methanesulfonic acid, which is odorl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odor
An odor (American English) or odour ( Commonwealth English; see spelling differences) is a smell or a scent caused by one or more volatilized chemical compounds generally found in low concentrations that humans and many animals can perceive via their olfactory system. While ''smell'' can refer to pleasant and unpleasant odors, the terms ''scent'', ''aroma'', and ''fragrance'' are usually reserved for pleasant-smelling odors and are frequently used in the food and cosmetic industry to describe floral scents or to refer to perfumes. Odor physiology Sense of smell The perception of odors, or sense of smell, is mediated by the olfactory nerve. The olfactory receptor (OR) cells are neurons present in the olfactory epithelium, which is a small patch of tissue at the back of the nasal cavity. There are millions of olfactory receptor neurons that act as sensory signaling cells. Each neuron has cilia in direct contact with the air. Odorous molecules bind to receptor pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Christopher Zeise
William Christopher Zeise (15 October 1789 – 12 November 1847) was a Danish organic chemist. He is best known for synthesising one of the first organometallic compounds, named Zeise's salt in his honour. He also performed pioneering studies in organosulfur chemistry, discovering the xanthates in 1823. Early life William Christopher Zeise was born 15 October 1789 in Slagelse, the son of apothecary Frederick Zeise (1754–1836), who was an old friend of physicist Hans Christian Ørsted's father. Zeise attended Slagelse Latin school with the poet Bernhard Severin Ingemann. He moved to Copenhagen in 1805 to take up an apprenticeship under Gottfried Becker as a pharmacy assistant (''Apoteksmedhjælper'') at the Royal Court Pharmacy. Becker, an accomplished chemist, was employed as extraordinary professor of chemistry at the University. However, Zeise felt dissatisfied there and returned home after only a few months, complaining of health issues. Around this time, his interes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turkey Vultures
Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armenia, Azerbaijan, and Iran to the east; Iraq, Syria, and the Mediterranean Sea to the south; and the Aegean Sea, Greece, and Bulgaria to the west. Turkey is home to over 85 million people; most are ethnic Turkish people, Turks, while ethnic Kurds in Turkey, Kurds are the Minorities in Turkey, largest ethnic minority. Officially Secularism in Turkey, a secular state, Turkey has Islam in Turkey, a Muslim-majority population. Ankara is Turkey's capital and second-largest city. Istanbul is its largest city and economic center. Other major cities include İzmir, Bursa, and Antalya. First inhabited by modern humans during the Late Paleolithic, present-day Turkey was home to List of ancient peoples of Anatolia, various ancient peoples. The Hattians ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unocal Corporation
Union Oil Company of California, and its holding company Unocal Corporation, together known as Unocal was a major petroleum explorer and marketer in the late 19th century, through the 20th century, and into the early 21st century. It was headquartered in El Segundo, California, United States. Unocal was involved in domestic and global energy projects. Unocal was one of the key players in the CentGas consortium, which attempted to build the Trans-Afghanistan Pipeline to run from the Caspian area, through Afghanistan, to the Indian Ocean, at a time after the Taliban siege of Kabul in 1996. On August 10, 2005, Unocal merged its entire upstream petroleum business with Chevron and became a wholly-owned subsidiary. Unocal then ceased operations as an independent company, but continues to conduct many operations as Union Oil Company of California, a Chevron company. History The Union Oil Company of California was founded on October 17, 1890, in Santa Paula, California, by Ly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cabbage
Cabbage, comprising several cultivars of '' Brassica oleracea'', is a leafy green, red (purple), or white (pale green) biennial plant grown as an annual vegetable crop for its dense-leaved heads. It is descended from the wild cabbage ( ''B. oleracea'' var. ''oleracea''), and belongs to the " cole crops" or brassicas, meaning it is closely related to broccoli and cauliflower (var. ''botrytis''); Brussels sprouts (var. ''gemmifera''); and Savoy cabbage (var. ''sabauda''). A cabbage generally weighs between . Smooth-leafed, firm-headed green cabbages are the most common, with smooth-leafed purple cabbages and crinkle-leafed savoy cabbages of both colours being rarer. Under conditions of long sunny days, such as those found at high northern latitudes in summer, cabbages can grow quite large. , the heaviest cabbage was . Cabbage heads are generally picked during the first year of the plant's life cycle, but plants intended for seed are allowed to grow a second year and m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Durian
The durian () is the edible fruit of several tree species belonging to the genus ''Durio''. There are 30 recognized species, at least nine of which produce edible fruit. ''Durio zibethinus'', native to Borneo and Sumatra, is the only species available on the international market. It has over 300 named varieties in Thailand and over 200 in Malaysia as of 2021. Other species are sold in their local regions. Known in some regions as the "king of fruits", the durian is distinctive for its large size, strong odour, and Spine (botany), thorn-covered peel (fruit), rind. The fruit can grow as large as long and in diameter, and it typically weighs . Its shape ranges from oblong to round, the colour of its husk from green to brown, and its flesh from pale yellow to red, depending on the species. Some people regard the durian as having a pleasantly sweet fragrance, whereas others find the aroma overpowering and unpleasant. The persistence of its strong odour, which may linger for sev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Onion
An onion (''Allium cepa'' , from Latin ), also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus '' Allium''. The shallot is a botanical variety of the onion which was classified as a separate species until 2011. The onion's close relatives include garlic, scallion, leek, and chives. The genus contains several other species variously called onions and cultivated for food, such as the Japanese bunching onion '' Allium fistulosum'', the tree onion ''Allium'' × ''proliferum'', and the Canada onion '' Allium canadense''. The name '' wild onion'' is applied to a number of ''Allium'' species, but ''A. cepa'' is exclusively known from cultivation. Its ancestral wild original form is not known, although escapes from cultivation have become established in some regions. The onion is most frequently a biennial or a perennial plant, but is usually treated as an annual and harvested in its first growing season. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leek
A leek is a vegetable, a cultivar of ''Allium ampeloprasum'', the broadleaf wild leek (synonym (taxonomy), syn. ''Allium porrum''). The edible part of the plant is a bundle of Leaf sheath, leaf sheaths that is sometimes erroneously called a "stem" or "stalk". The genus ''Allium'' also contains the onion, garlic, shallot, scallion, chives, and Allium chinense, Chinese onion. Three closely related vegetables—elephant garlic, kurrat and Persian leek or ''tareh''—are also cultivars of ''A. ampeloprasum'', although different in their culinary uses. Etymology Historically, many scientific names were used for leeks, but they are now all treated as cultivars of ''A. ampeloprasum''. The name ''leek'' developed from the Old English word , from which the modern English name for garlic also derives. means 'onion' in Old English and has cognates in other Germanic languages: Danish ' 'onion', Icelandic ' 'onion', Norwegian ' 'onion', Swedish ' 'onion', German ' 'leek', Dutch ' '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humans
Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing#Evolution of hairlessness, hairlessness, bipedality, bipedalism, and high Human intelligence, intelligence. Humans have large Human brain, brains, enabling more advanced cognitive skills that facilitate successful adaptation to varied environments, development of sophisticated tools, and formation of complex social structures and civilizations. Humans are Sociality, highly social, with individual humans tending to belong to a Level of analysis, multi-layered network of distinct social groups — from families and peer groups to corporations and State (polity), political states. As such, social interactions between humans have established a wide variety of Value theory, values, norm (sociology), social norms, languages, and traditions (co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salt Metathesis Reaction
A salt metathesis reaction (also called a double displacement reaction, double replacement reaction, or double decomposition) is a type of chemical reaction in which two ionic compounds in aqueous solution exchange their component ions to form two new compounds. Often, one of these new compounds is a precipitate, gas, or weak electrolyte, driving the reaction forward. :AB + CD -> AD + CB \mathitA_\mathitD_\mathit + \mathitC_\mathitB_\mathit --> In older literature, the term double decomposition is common. The term double decomposition is more specifically used when at least one of the substances does not dissolve in the solvent, as the ligand or ion exchange takes place in the solid state of the reactant. For example: :AX(aq) + BY(s) → AY(aq) + BX(s). Types of reactions Counterion exchange Salt metathesis is a common technique for exchanging counterions. The choice of reactants is guided by a solubility chart or lattice energy. HSAB theory can also be used to predict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henri Victor Regnault
Henri Victor Regnault (21 July 1810 – 19 January 1878) was a French chemist and physicist best known for his careful measurements of the thermal properties of gases. He was an early thermodynamicist and was mentor to William Thomson in the late 1840s. He never used his first given name, and was known throughout his lifetime as Victor Regnault. Biography Born in Aix-la-Chapelle in 1810 (modern Aachen, Germany and at that time under French rule), he moved to Paris at the age of eight, following the death of his parents. There, he worked for an upholstery firm until he was eighteen. In 1830, he was admitted to the École Polytechnique, and in 1832 he graduated from the École des mines. Working under Justus von Liebig at Gießen, Regnault distinguished himself in the nascent field of organic chemistry by synthesizing several chlorinated hydrocarbons (e.g. vinyl chloride in 1835, dichloromethane and perchloroethylene in 1839, 1,1,1-Trichloroethane in 1838 or 1840), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
