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Quercitannic Acid
Quercitannic acid is one of the two forms of tannic acid found in oak bark and leaves. The other form is called gallotannic acid and is found in oak galls. The quercitannic acid molecule is also present in quercitron, a yellow dye obtained from the bark of the Eastern black oak (''Quercus velutina''), a forest tree indigenous in North America. It is described as a yellowish brown amorphous substance. In 1838, Jöns Jacob Berzelius wrote that quercitannate is used to dissolve morphine. In 1865 in the fifth volume of "A dictionary of chemistry", Henry Watts wrote : It exhibits with ferric salts the same reactions as gallotannic acid. It differs however from the latter in not being convertible into gallic acid, and not yielding pyrogallic acid by dry distillation. It is precipitated by sulfuric acid in red flocks. ( Stenhouse, Ann. Ch. Pharm. xlv. 16.) According to Rochleder (ibid lxiii. 202), the tannic acid of black tea is the same as that of oak-bark. In 1880, Etti gave for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tannic Acid
Tannic acid is a specific form of tannin, a type of polyphenol. Its weak acidity (Acid dissociation constant, pKa around 6) is due to the numerous phenol groups in the structure. The chemical formula for commercial tannic acid is often given as C76H52O46, which corresponds with decagalloyl glucose, but in fact it is a mixture of polygalloyl glucoses or polygalloyl quinic acid esters with the number of gallic acid, galloyl moieties per molecule ranging from 2 up to 12 depending on the plant source used to extract the tannic acid. Commercial tannic acid is usually extracted from any of the following plant parts: Tara pods (''Caesalpinia spinosa''), gallnuts from ''Rhus semialata'' or ''Quercus infectoria'' or Sicilian sumac leaves (''Rhus coriaria''). According to the definitions provided in external references such as international pharmacopoeia, Food Chemicals Codex and FAO-WHO tannic acid monograph only tannins obtained from the above-mentioned plants can be considered as tanni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oak Bark
Tanbark is the bark of certain species of trees, traditionally used for tanning hides into leather. The words "tannin", " tanning", " tan," and " tawny" are derived from the Medieval Latin , "to convert into leather." Bark mills are horse- or oxen-driven or water-powered edge mills and were used in earlier times to shred the tanbark to derive tannins for the leather industry. A "barker" was a person who stripped bark from trees to supply bark mills. Tanbark around the world In Europe, oak is a common source of tanbark. Quercitannic acid is the chief constituent found in oak barks. The bark is taken from young branches and twigs in oak coppices and can be up to 4 mm thick; it is grayish-brown on the outside and brownish-red on the inner surface. In some areas of the United States, such as central Pennsylvania and northern California, "mulch" is often called tanbark, even by manufacturers and distributors. In these areas, the word "mulch" may refer to peat moss or t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quercitron
Quercitron is a yellow natural dye obtained from the bark of the Eastern Black Oak (''Quercus velutina''), a forest tree indigenous in North America. It was formerly called Dutch pink, English pink, or Italian pink. The name is a shortened form of quercicitron, from Latin ''quercus'', oak, and ''citron'', lemon, and was invented by Edward Bancroft (1744–1821), who by act of Parliament (25 Geo. 3. c. 38) in 1785 was granted special privileges in regard to the importation and use of the substance. The dyestuff is prepared by grinding the bark in bark mill, mills after it has been freed from its black Epidermis (botany), epidermal layer, and sifting the product to separate the fibrous matter, the fine yellow powder which remains forming the quercitron of commerce. The ruddy-orange decoction of quercitron contains quercitannic acid, whence its use in Tanning (leather), tanning, and an active dyeing principle, quercitrin, C21H20O11. The latter substance is a glycoside, and in aque ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jöns Jacob Berzelius
Baron Jöns Jacob Berzelius (; 20 August 1779 – 7 August 1848) was a Swedish chemist. Berzelius is considered, along with Robert Boyle, John Dalton, and Antoine Lavoisier, to be one of the founders of modern chemistry. Berzelius became a member of the Royal Swedish Academy of Sciences in 1808 and served from 1818 as its principal functionary. He is known in Sweden as the "Father of Swedish Chemistry". During his lifetime he did not customarily use his first given name, and was universally known simply as Jacob Berzelius. Although Berzelius began his career as a physician, his enduring contributions were in the fields of electrochemistry, chemical bonding and stoichiometry. In particular, he is noted for his determination of atomic weights and his experiments that led to a more complete understanding of the principles of stoichiometry, which is the branch of chemistry pertaining to the quantitative relationships between elements in chemical compounds and chemical reactions and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Watts (chemist)
Henry Watts (1815–1884) was an English chemist. Life He was born in London on 20 January 1815. He went to a private school, and was articled at the age of fifteen as an architect and surveyor; but went on to support himself by teaching, chiefly mathematical, privately and at a school. He then attended University College, London. In 1841 he graduated B.A. in the University of London. In 1846 he became assistant to George Fownes, professor of practical chemistry at University College, and occupied this post, after Fownes's death in 1849, until 1857, under Professor Alexander William Williamson. Having an impediment in speech he found himself unable to obtain a professorship, and worked on the literature of chemistry. In 1847 he was elected fellow of the Chemical Society. On 17 December 1849 he was elected editor of the Chemical Society's ''Journal'', and about the beginning of 1860 he also became librarian to the society. Early in 1871 it was decided to print in the society's j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferric
In chemistry, iron(III) or ''ferric'' refers to the chemical element, element iron in its +3 oxidation number, oxidation state. ''Ferric chloride'' is an alternative name for iron(III) chloride (). The adjective ''ferrous'' is used instead for iron(II) salts, containing the cation Fe2+. The word ''wikt:ferric, ferric'' is derived from the Latin word , meaning "iron". Although often abbreviated as Fe3+, that naked ion does not exist except under extreme conditions. Iron(III) centres are found in many compounds and coordination complexes, where Fe(III) is bonded to several Ligand, ligands. A molecular ferric complex is the anion ferrioxalate, , with three bidentate oxalate ions surrounding the Fe core. Relative to lower oxidation states, ferric is less common in organoiron chemistry, but the ferrocenium cation is well known. Iron(III) in biology All known forms of life require iron, which usually exists in Fe(II) or Fe(III) oxidation states. Many proteins in living beings cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salt (chemistry)
In chemistry, a salt or ionic compound is a chemical compound consisting of an assembly of positively charged ions ( cations) and negatively charged ions ( anions), which results in a compound with no net electric charge (electrically neutral). The constituent ions are held together by electrostatic forces termed ionic bonds. The component ions in a salt can be either inorganic, such as chloride (Cl−), or organic, such as acetate (). Each ion can be either monatomic, such as sodium (Na+) and chloride (Cl−) in sodium chloride, or polyatomic, such as ammonium () and carbonate () ions in ammonium carbonate. Salts containing basic ions hydroxide (OH−) or oxide (O2−) are classified as bases, such as sodium hydroxide and potassium oxide. Individual ions within a salt usually have multiple near neighbours, so they are not considered to be part of molecules, but instead part of a continuous three-dimensional network. Salts usually form crystalline structures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gallic Acid
Gallic acid (also known as 3,4,5-trihydroxybenzoic acid) is a trihydroxybenzoic acid with the formula C6 H2( OH)3CO2H. It is classified as a phenolic acid. It is found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants. It is a white solid, although samples are typically brown owing to partial oxidation. Salts and esters of gallic acid are termed "gallates". Its name is derived from oak galls, which were historically used to prepare tannic acid. Despite the name, gallic acid does not contain gallium. Isolation and derivatives Gallic acid is easily freed from gallotannins by acidic or alkaline hydrolysis. When heated with concentrated sulfuric acid, gallic acid converts to rufigallol. Hydrolyzable tannins break down on hydrolysis to give gallic acid and glucose or ellagic acid and glucose, known as gallotannins and ellagitannins, respectively. Biosynthesis Gallic acid is formed from 3-dehydroshikimate by the action of the enzyme shikimat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrogallic Acid
Pyrogallol is an organic compound with the formula C6H3(OH)3. It is a water-soluble, white solid although samples are typically brownish because of its sensitivity toward oxygen. It is one of three isomers of benzenetriols. Production and reactions It is produced in the manner first reported by Scheele in 1786: heating gallic acid to induce decarboxylation. Gallic acid is also obtained from tannin. Many alternative routes have been devised. One preparation involves treating ''para''-chlorophenoldisulfonic acid with potassium hydroxide, a variant on the time-honored route to phenols from sulfonic acids. Polyhydroxybenzenes are relatively electron-rich. One manifestation is the easy C-acetylation of pyrogallol. Uses It was once used in hair dyeing, dyeing of suturing materials. It also has antiseptic properties. In alkaline solution, pyrogallol undergoes deprotonation. Such solutions absorb oxygen from the air, turning brown. This conversion can be used to determine t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfuric Acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, 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 Viscosity, viscous liquid that is Miscibility, miscible with water. Pure sulfuric acid does not occur naturally due to its Dehydration reaction, strong affinity to water vapor; it is Hygroscopy, hygroscopic and readily absorbs water vapor from the Atmosphere of Earth, air. Concentrated sulfuric acid is a strong oxidant with powerful dehydrating properties, making it highly corrosive towards other materials, from rocks to metals. 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 releas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Stenhouse
John Stenhouse FRS FRSE FIC FCS (21 October 1809 – 31 December 1880) was a British chemist. In 1854, he invented one of the first practical respirators. He was a co-founder of the Chemical Society in 1841. Life John Stenhouse was born in Barrhead in Glasgow on 21 October 1809. He was the eldest son of William Stenhouse, a calico-printer in the family firm of John Stenhouse & Co of 302 High Street, Glasgow, and Elizabeth Currie; he was the only one of their children to survive beyond infancy. After education at the Glasgow Grammar School, he studied at the University of Glasgow from 1824 to 1828. Initially he intended to pursue a career in literature, but later his interests switched to chemistry, which he studied first under Professor Thomas Graham at the university and then under Dr. Thomas Thomson at Anderson's University in Glasgow (now part of the University of Strathclyde, one of whose buildings is named after him). During 1837–1839, he attended the chemical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anhydride
An acid anhydride is a type of chemical compound derived by the removal of water molecules from an acid (chemistry), acid. In organic chemistry, organic acid anhydrides contain the functional group . Organic acid anhydrides often form when one equivalent (chemistry), equivalent of water is removed from two equivalents of an organic acid in a dehydration reaction. In inorganic chemistry, an acid anhydride refers to an acidic oxide, an oxide that reacts with water to form an oxyacid (an inorganic acid that contains oxygen or carbonic acid), or with a base (chemistry), base to form a salt (chemistry), salt. See also * Base anhydride, an oxide that reacts with water to form a hydroxide salt References {{Chemistry index ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
