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Croconate Blue
Croconate blue or 1,2,3-tris(dicyanomethylene)croconate is a divalent anion with chemical formula or ((N≡C−)2C=)3(C5O2)2−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the croconate oxocarbon anion through the replacement of three oxygen atoms by dicyanomethylene groups =C(−C≡N)2. The term Croconate Blue as a dye name specifically refers to the dipotassium salt . History and synthesis The anion was synthesized and characterized by A. Fatiadi in 1978, together with croconate violet. He obtained the corresponding acid, croconate acid blue by treating croconic acid with malononitrile in water solution at 80–90 °C. Alexander J. Fatiadi (1978), "Synthesis of 1,3-(dicyanomethylene)croconate salts. New bond-delocalized dianion, Croconate Violet". ''Journal of the American Chemical Society'', volume 100 issue 8, pages 2586–2587. Alexander J. Fatiadi (1980), "Pseudooxocarbons. Synthesis of 1,2,3-tris(dicyanomethyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Croconate Blue
Croconate blue or 1,2,3-tris(dicyanomethylene)croconate is a divalent anion with chemical formula or ((N≡C−)2C=)3(C5O2)2−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the croconate oxocarbon anion through the replacement of three oxygen atoms by dicyanomethylene groups =C(−C≡N)2. The term Croconate Blue as a dye name specifically refers to the dipotassium salt . History and synthesis The anion was synthesized and characterized by A. Fatiadi in 1978, together with croconate violet. He obtained the corresponding acid, croconate acid blue by treating croconic acid with malononitrile in water solution at 80–90 °C. Alexander J. Fatiadi (1978), "Synthesis of 1,3-(dicyanomethylene)croconate salts. New bond-delocalized dianion, Croconate Violet". ''Journal of the American Chemical Society'', volume 100 issue 8, pages 2586–2587. Alexander J. Fatiadi (1980), "Pseudooxocarbons. Synthesis of 1,2,3-tris(dicyanomethyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malononitrile
Malononitrile is an organic compound nitrile with the formula . It is a colorless or white solid. It can be prepared by dehydration of cyanoacetamide. Malononitrile is relatively acidic, with a p''K''a of 11 in water. This allows it to be used in the Knoevenagel condensation, for example in the preparation of CS gas: Malononitrile is a suitable starting material for the Gewald reaction, where the nitrile condenses with a ketone or aldehyde in the presence of elemental sulfur and a base to produce a 2-aminothiophene. See also * Malonic acid * Diethyl malonate Diethyl malonate, also known as DEM, is the diethyl ester of malonic acid. It occurs naturally in grapes and strawberries as a colourless liquid with an apple-like odour, and is used in perfumes. It is also used to synthesize other compounds su ... References External links WebBook page for C3H2N2 {{Authority control Alkanedinitriles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Croconate Violet
Croconate violet or 1,3-bis(dicyanomethylene)croconate is a divalent anion with chemical formula or ((N≡C−)2C=)2(C5O3)2−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the croconate oxocarbon anion through the replacement of two oxygen atoms by dicyanomethylene groups =C(−C≡N)2. Its systematic name is 3,5-bis(dicyanomethylene)-1,2,4-trionate. The term croconate violet as a dye name specifically refers to the dipotassium salt . History and synthesis The anion was synthesized and characterized by Alexander Fatiadi in 1978. He obtained the potassium salt by treating dipotassium croconate with malononitrile in water solution at 80–90 °C. Alexander J. Fatiadi (1978), "Synthesis of 1,3-(dicyanomethylene)croconate salts. New bond-delocalized dianion, "Croconate Violet"". ''Journal of the American Chemical Society'', volume 100 issue 8, pages 2586–2587. The dipotassium salt crystallizes from water as a dihydrate in dee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-(Dicyanomethylene)croconate
2-(Dicyanomethylene)croconate is a divalent anion with chemical formula or ((N≡C−)2C=)(C5O4)2−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the croconate oxocarbon anion through the replacement of one oxygen atom by a dicyanomethylene group =C(−C≡N)2. The anion was synthesized and characterized by A. Fatiadi in 1980, by hydrolysis of croconate violet treated with potassium hydroxide.Alexander J. Fatiadi (1980), "Pseudooxocarbons. Synthesis of 1,2,3-tris(dicyanomethylene)croconate salts. A new bond-delocalized dianion, croconate blue". ''Journal of Organic Chemistry'' volume 45, pages 1338–1339. It gives an orange solution in water. See also * Croconate violet, 1,3-bis(dicyanomethylene)croconate * Croconate blue Croconate blue or 1,2,3-tris(dicyanomethylene)croconate is a divalent anion with chemical formula or ((N≡C−)2C=)3(C5O2)2−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetramethylammonium
Tetramethylammonium (TMA) or (Me4N+) is the simplest quaternary ammonium cation, consisting of four methyl groups attached to a central nitrogen atom, and is isoelectronic with neopentane. It is positively charged and can only be isolated in association with a counter-ion. Common salts include tetramethylammonium chloride and tetramethylammonium hydroxide. Tetramethylammonium salts are commonly used in chemical synthesis and are widely employed in pharmacological research. Common nomenclature In the toxicological literature, ''naturally occurring'' tetramethylammonium (anion unspecified) is often referred to by the name "tetramine". Unfortunately, this non-systematic or "trivial" name is also used for other chemical entities, including a toxic rodenticide (Tetramethylenedisulfotetramine). Similarly, the acronym "TMA", which is frequently used for tetramethylammonium in the pharmacological literature, may also refer to the investigational drug 3,4,5-trimethoxyamphetamine, which, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Resistivity And Conductivity
Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric current. A low resistivity indicates a material that readily allows electric current. Resistivity is commonly represented by the Greek letter (rho). The SI unit of electrical resistivity is the ohm-meter (Ω⋅m). For example, if a solid cube of material has sheet contacts on two opposite faces, and the resistance between these contacts is , then the resistivity of the material is . Electrical conductivity or specific conductance is the reciprocal of electrical resistivity. It represents a material's ability to conduct electric current. It is commonly signified by the Greek letter ( sigma), but (kappa) (especially in electrical engineering) and (gamma) are sometimes used. The SI unit of electrical conductivity is siemens per metre (S/m). Resistivity and conductivity are intensi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Hydroxide
Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which exploit its caustic nature and its reactivity toward acids. An estimated 700,000 to 800,000 tonnes were produced in 2005. KOH is noteworthy as the precursor to most soft and liquid soaps, as well as numerous potassium-containing chemicals. It is a white solid that is dangerously corrosive. Properties and structure KOH exhibits high thermal stability. Because of this high stability and relatively low melting point, it is often melt-cast as pellets or rods, forms that have low surface area and convenient handling properties. These pellets become tacky in air because KOH is hygroscopic. Most commercial samples are ca. 90% pure, the remainder being water and carbonates. Its dissolution in water is strongly exothermic. Concentrated aqueous solut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrate
In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understood. Chemical nature Inorganic chemistry Hydrates are inorganic salts "containing water molecules combined in a definite ratio as an integral part of the crystal" that are either bound to a metal center or that have crystallized with the metal complex. Such hydrates are also said to contain ''water of crystallization'' or ''water of hydration''. If the water is heavy water in which the constituent hydrogen is the isotope deuterium, then the term ''deuterate'' may be used in place of ''hydrate''. A colorful example is cobalt(II) chloride, which turns from blue to red upon hydration, and can therefore be used as a water indicator. The notation "''hydrated compound''⋅''n''", where ''n'' is the number of water molecules per formula un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Methoxide
Potassium methoxide is the alkoxide of methanol with the counterion potassium and is used as a strong base and as a catalyst for transesterification, in particular for the production of biodiesel. Preparation The preparation of potassium methoxide can be achieved on the laboratory scale by the (strongly exothermic) reaction of metallic potassium and methanol upon the release of equimolar amounts of hydrogen. The reaction of metal hydrides (potassium hydride) with methanol forming potassium methoxide is also possible but less important. The exothermic reaction of potassium hydroxide with methanol leads in an equilibrium reaction to potassium methanolate and water (avoiding formation of highly inflammable hydrogen gas). In a continuous process the formed water must be removed permanently. The complete removal of the water is critical for the reaction conversion, due to the pronounced hygroscopy of potassium hydroxide, which contains about 10% of water. The significantly hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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