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Oxalate Esters
Oxalate (IUPAC: ethanedioate) is an anion with the formula C2O42−. This dianion is colorless. It occurs naturally, including in some foods. It forms a variety of salts, for example sodium oxalate (Na2C2O4), and several esters such as dimethyl oxalate (C2O4(CH3)2). It is a conjugate base of oxalic acid. At neutral pH in aqueous solution, oxalic acid converts completely to oxalate. Relationship to oxalic acid The dissociation of protons from oxalic acid proceeds in a stepwise manner; as for other polyprotic acids, loss of a single proton results in the monovalent hydrogenoxalate anion . A salt with this anion is sometimes called an acid oxalate, monobasic oxalate, or hydrogen oxalate. The equilibrium constant ( ''K''a) for loss of the first proton is (p''K''a = 1.27). The loss of the second proton, which yields the oxalate ion, has an equilibrium constant of (p''K''a = 4.28). These values imply, in solutions with neutral pH, no oxalic acid and only trace am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogenoxalate
Hydrogenoxalate or hydrogen oxalate is an anion with chemical formula or , derived from oxalic acid by the loss of a single proton; or, alternatively, from the oxalate anion by addition of a proton. The name is also used for any salt containing this anion. Especially in older literature, hydrogenoxalates may also be referred to as bioxalates, acid oxalates, or monobasic oxalates. Hydrogenoxalate is amphoteric, in that it can react both as an acid or a base. Well characterized salts include sodium hydrogenoxalate (), potassium hydrogenoxalate (), ammonium hydrogenoxalate (), rubidium hydrogenoxalate () and dimethylammonium hydrogenoxalate (()). Structure Most hydrogenoxalate salts are hydrated. For example, potassium hydrogen oxalate crystallizes as 2·. These materials exhibit extended structures resulting from extensive hydrogen bonding and anion-cation interactions. The hydrates dehydrate upon heating: :2· → 2 + Proton transfer in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon–carbon Bond
A carbon–carbon bond is a covalent bond between two carbon atoms. The most common form is the single bond: a bond composed of two electrons, one from each of the two atoms. The carbon–carbon single bond is a sigma bond and is formed between one hybridized orbital from each of the carbon atoms. In ethane, the orbitals are sp3- hybridized orbitals, but single bonds formed between carbon atoms with other hybridizations do occur (e.g. sp2 to sp2). In fact, the carbon atoms in the single bond need not be of the same hybridization. Carbon atoms can also form double bonds in compounds called alkenes or triple bonds in compounds called alkynes. A double bond is formed with an sp2-hybridized orbital and a p-orbital that is not involved in the hybridization. A triple bond is formed with an sp-hybridized orbital and two p-orbitals from each atom. The use of the p-orbitals forms a pi bond. Chains and branching Carbon is one of the few elements that can form long chains of its ow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poppy Seed
Poppy seed is an oilseed obtained from the opium poppy (''Papaver somniferum''). The tiny, kidney-shaped seeds have been harvested from dried seed pods by various civilizations for thousands of years. It is still widely used in many countries, especially in Central Europe and South Asia, where it is legally grown and sold in shops. The seeds are used whole or ground into meal as an ingredient in many foods – especially in pastry and bread – and they are pressed to yield poppyseed oil. History The poppy seed is mentioned in ancient medical text from many civilizations. For instance, the Egyptian papyrus scroll named Ebers Papyrus, written c. 1550 BC, lists poppy seed as a sedative. The Minoan civilization (approximately 2700 to 1450 BC), a Bronze Age civilization which arose on the island of Crete, cultivated poppies for their seed, and used a milk, opium and honey mixture to calm crying babies. The Sumerians are another civilization that are known to have grown poppy seeds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parsley
Parsley, or garden parsley (''Petroselinum crispum'') is a species of flowering plant in the family Apiaceae that is native to the central and eastern Mediterranean region (Sardinia, Lebanon, Israel, Cyprus, Turkey, southern Italy, Greece, Portugal, Spain, Malta, Morocco, Algeria, and Tunisia), but has been naturalized elsewhere in Europe, and is widely cultivated as a herb, and a vegetable. Parsley is widely used in European, Middle Eastern, and American cuisine. Curly leaf parsley is often used as a garnish. In central Europe, eastern Europe, and southern Europe, as well as in western Asia, many dishes are served with fresh green chopped parsley sprinkled on top. Flat leaf parsley is similar, but it is easier to cultivate, some say it has a stronger flavor. Root parsley is very common in central, eastern, and southern European cuisines, where it is used as a snack or a vegetable in many soups, stews, and casseroles. It is believed to have been originally grown in Sardinia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Pepper
Black pepper (''Piper nigrum'') is a flowering vine in the family Piperaceae, cultivated for its fruit, known as a peppercorn, which is usually dried and used as a spice and seasoning. The fruit is a drupe (stonefruit) which is about in diameter (fresh and fully mature), dark red, and contains a stone which encloses a single pepper seed. Peppercorns and the ground pepper derived from them may be described simply as ''pepper'', or more precisely as ''black pepper'' (cooked and dried unripe fruit), ''green pepper'' (dried unripe fruit), or ''white pepper'' (ripe fruit seeds). Black pepper is native to the Malabar Coast of India, and the Malabar pepper is extensively cultivated there and in other tropical regions. Ground, dried, and cooked peppercorns have been used since antiquity, both for flavour and as a traditional medicine. Black pepper is the world's most traded spice, and is one of the most common spices added to cuisines around the world. Its spiciness is due to the ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carambola
Carambola, also known as star fruit, is the fruit of ''Averrhoa carambola'', a species of tree native to tropical Southeast Asia. The mildly poisonous fruit is commonly consumed in parts of Brazil, Southeast Asia, South Asia, the South Pacific, Micronesia, parts of East Asia, the United States, and the Caribbean and contains the neurotoxin caramboxin. The tree is cultivated throughout tropical areas of the world. The fruit has distinctive ridges running down its sides (usually 5–6). When cut in cross-section, it resembles a star, giving it the name of ''star fruit''. The entire fruit is edible, usually raw, and may be cooked or made into relishes, preserves, garnish, and juices. Origins and distribution The center of diversity and the original range of ''Averrhoa carambola'' is tropical Southeast Asia, where it has been cultivated over centuries. It was introduced to the Indian Subcontinent and Sri Lanka by Austronesian traders, along with ancient Austronesian cultig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxalis
''Oxalis'' ( (American English) or (British English)) is a large genus of flowering plants in the wood-sorrel family Oxalidaceae, comprising over 550 species. The genus occurs throughout most of the world, except for the Polar region, polar areas; species diversity is particularly rich in tropical Brazil, Mexico, and South Africa. Many of the species are known as wood sorrels (sometimes written "woodsorrels" or "wood-sorrels") as they have an acidic taste reminiscent of the sorrel proper (''Rumex acetosa''), which is only distantly related. Some species are called yellow sorrels or pink sorrels after the color of their flowers instead. Other species are colloquially known as false shamrocks, and some called sourgrasses. For the genus as a whole, the term oxalises is also used. Description and ecology These plants are annual plant, annual or perennial plant, perennial. The leaves are divided into three to ten or more obovate and top-notched leaflets, arranged palmately with all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sorrel
Sorrel (''Rumex acetosa''), also called common sorrel or garden sorrel, is a perennial herbaceous plant in the family Polygonaceae. Other names for sorrel include spinach dock and narrow-leaved dock ('dock' being a common name for the genus ''Rumex''). Sorrel is native to Eurasia and a common plant in grassland habitats. It is often cultivated as a leaf vegetable or herb. Description Sorrel is a slender herbaceous perennial plant about high, with roots that run deep into the ground, as well as juicy stems and arrow-shaped ( sagittate) leaves. The lower leaves are in length with long petioles and a membranous ocrea formed of fused, sheathing stipules. The upper ones are sessile, and frequently become crimson. It has whorled spikes of reddish-green flowers, which bloom in early summer, becoming purplish. The species is dioecious, with stamens and pistils on different plants. Subspecies Several subspecies have been named. Not all are cultivated. * ''Rumex acetosa'' ssp. '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chenopodium Album
''Chenopodium album'' is a fast-growing weedy annual plant in the genus ''Chenopodium''. Though cultivated in some regions, the plant is elsewhere considered a weed. Common names include lamb's quarters, melde, goosefoot, wild spinach and fat-hen, though the latter two are also applied to other species of the genus ''Chenopodium'', for which reason it is often distinguished as white goosefoot.BSBIDatabase of names (xls file) ''Chenopodium album'' is extensively cultivated and consumed in Northern India, Nepal, and Pakistan as a food crop known as ''bathua''. Distribution Its native range is obscure due to extensive cultivation, but includes most of Europe,Flora Europaea''Chenopodium album''/ref> from where Linnaeus described the species in 1753.Linnaeus, C. (1753). ''Species Plantarum'' 1: 219Facsimile Plants native in eastern Asia are included under ''C. album'', but often differ from European specimens.Flora of China''Chenopodium album''/ref> It is widely naturalised elsewher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buckwheat
Buckwheat (''Fagopyrum esculentum''), or common buckwheat, is a flowering plant in the knotweed family Polygonaceae cultivated for its grain-like seeds and as a cover crop. The name "buckwheat" is used for several other species, such as '' Fagopyrum tataricum'', a domesticated food plant raised in Asia. Despite its name, buckwheat is not closely related to wheat. It is not a cereal, nor is it even a member of the grass family. Buckwheat is related to sorrel, knotweed, and rhubarb, and is known as a pseudocereal because its seeds' culinary use is the same as cereals, owing to their high starch content. Etymology The name "buckwheat" or "beech wheat" comes from its triangular seeds, which resemble the much larger seeds of the beech nut from the beech tree, and the fact that it is used like wheat. The word may be a translation of Middle Dutch ''boecweite'': ''boec'' (Modern Dutch ''beuk''), "beech" (see PIE *''bhago''-) and ''weite'' (Mod. Dut. ''tarwe'', antiquated Dut. '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhubarb
Rhubarb is the fleshy, edible stalks ( petioles) of species and hybrids (culinary rhubarb) of ''Rheum'' in the family Polygonaceae, which are cooked and used for food. The whole plant – a herbaceous perennial growing from short, thick rhizomes – is also called rhubarb. Historically, different plants have been called "rhubarb" in English. The large, triangular leaves contain high levels of oxalic acid and anthrone glycosides, making them inedible. The small flowers are grouped in large compound leafy greenish-white to rose-red inflorescences. The precise origin of culinary rhubarb is unknown. The species ''Rheum rhabarbarum'' (syn. ''R. undulatum'') and '' R. rhaponticum'' were grown in Europe before the 18th century and used for medicinal purposes. By the early 18th century, these two species and a possible hybrid of unknown origin, ''R.'' × ''hybridum'', were grown as vegetable crops in England and Scandinavia. They readily hybridize, and culinary rh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinach
Spinach (''Spinacia oleracea'') is a leafy green flowering plant native to central and western Asia. It is of the order Caryophyllales, family Amaranthaceae, subfamily Chenopodioideae. Its leaves are a common edible vegetable consumed either fresh, or after storage using preservation techniques by canning, freezing, or dehydration. It may be eaten cooked or raw, and the taste differs considerably; the high oxalate content may be reduced by steaming. It is an annual plant (rarely biennial), growing as tall as . Spinach may overwinter in temperate regions. The leaves are alternate, simple, ovate to triangular, and very variable in size: long and broad, with larger leaves at the base of the plant and small leaves higher on the flowering stem. The flowers are inconspicuous, yellow-green, in diameter, and mature into a small, hard, dry, lumpy fruit cluster across containing several seeds. In 2018, world production of spinach was 26.3 million tonnes, with China alone accounti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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