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Melam (chemistry)
, Section2={{Chembox Properties , Formula = C6H9N11 , MolarMass = 235.21 g/mol , Appearance = white powder , Density = , MeltingPt = , MeltingPt_notes = , BoilingPt = , BoilingPt_notes = , Solubility = insoluble , SolubleOther = slightly soluble in acids , Solvent = , pKa = , pKb = , Section7={{Chembox Hazards , MainHazards = , NFPA-H = , NFPA-F = , NFPA-R = , NFPA-S = , FlashPt = , AutoignitionPt = , ExploLimits = , PEL = Melam (''N2''-(4,6-diamino-1,3,5-triazin-2-yl)-1,3,5-triazine-2,4,6-triamine) is a condensation product of melamine. Synthesis Melam was discovered by Liebig in 1834 from the residue of heating ammonium thiocyanate. Chemical property In the presence of 30% ammonia, melam undergoes hydrolysis to form ammeline and melamine. It also reacts with concentrated nitric acid, producing cyanuric acid. Upon heating, melam first loses ammonia to form melem, and then melon. References * B. Bann and S.A. Miller, "Melamines and de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melamine
Melamine is an organic compound with the formula C3H6N6. This white solid is a trimer of cyanamide, with a 1,3,5-triazine skeleton. Like cyanamide, it contains 67% nitrogen by mass, and its derivatives have fire retardant properties due to its release of nitrogen gas when burned or charred. Melamine can be combined with formaldehyde and other agents to produce melamine resins. Such resins are characteristically durable thermosetting plastic used in high pressure decorative laminates such as Formica, melamine dinnerware, laminate flooring, and dry erase boards. Melamine foam is used as insulation, soundproofing material and in polymeric cleaning products, such as Magic Eraser. Melamine was once illegally added to baby formula in China, in order to increase the apparent protein content. Ingestion of melamine may lead to reproductive damage, or bladder or kidney stones, and bladder cancer. It is also an irritant when inhaled or in contact with the skin or eyes. The U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liebig
Justus Freiherr von Liebig (12 May 1803 – 20 April 1873) was a German scientist who made major contributions to agricultural and biological chemistry, and is considered one of the principal founders of organic chemistry. As a professor at the University of Giessen, he devised the modern laboratory-oriented teaching method, and for such innovations, he is regarded as one of the greatest chemistry teachers of all time. He has been described as the "father of the fertilizer industry" for his emphasis on nitrogen and trace minerals as essential plant nutrients, and his formulation of the law of the minimum, which described how plant growth relied on the scarcest nutrient resource, rather than the total amount of resources available. He also developed a manufacturing process for beef extracts, and with his consent a company, called Liebig Extract of Meat Company, was founded to exploit the concept; it later introduced the Oxo brand beef bouillon cube. He popularized an earli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonium Thiocyanate
Ammonium thiocyanate is an inorganic compound with the formula NH4SCN. It is the salt of the ammonium cation and the thiocyanate anion. Uses Ammonium thiocyanate is used in the manufacture of herbicides, thiourea, and transparent artificial resins; in matches; as a stabilizing agent in photography; in various rustproofing compositions; as an adjuvant in textile dyeing and printing; as a tracer in oil fields; in the separation of hafnium from zirconium (important for the production of hafnium-free zircalloy for use in nuclear fuel cladding), and in titrimetric analyses. In May 1945, USAAF General Victor E. Betrandias advanced a proposal to his superior General Arnold to use of ammonium thiocyanate to reduce rice crops in Japan as part of the bombing raids on their country. Ammonium thiocyanate can also be used to determine the iron content in soft drinks by colorimetry. Ammonium thiocyanate may also be used to separate quinidine, from liquors, after the isolation of quinine fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to 45% of the world's food and fertilizers. Around 70% of ammonia is used to make fertilisers in various forms and composition, such as urea and Diammonium phosphate. Ammonia in pure form is also applied directly into the soil. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products. It is mainly collected by downward displacement of both air and water. Although common in nature—both terrestrially and in the outer planets of the Solar System—and in wide use, ammonia is bot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammeline
Ammeline (4,6-diamino-2-hydroxy-1,3,5-triazine) is a triazine derivative. It is the hydrolysis product of melamine. Synthesis Ammeline can be synthesized by the pyrolysis of urea or the condensation reaction among 2 moles of dicyandiamide and 1 mole of biuret. : 2 C2H4N4 + C2H5N3O2 → 2C3H5N5O + NH3 Chemical properties Ammeline is weakly acidic with pKa ~9. It can form nitrate, sulfate, chromate, and oxalate salts. Ammeline reacts with boiling dilute hydrochloric acid to form melem and ammonia. Ammeline is the first step in melamine hydrolysis. Further hydrolysis (e.g. boiling ammeline with dilute alkali) yields ammelide. References * {{cite journal , author = B. Bann and S.A. Miller , title = Melamines and derivatives of melamine , journal = Chemical Reviews ''Chemical Reviews'' is peer-reviewed scientific journal published twice per month by the American Chemical Society. It publishes review articles on all aspects of chemistry. It was established in 1924 by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitric Acid
Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitric acid has a concentration of 68% in water. When the solution contains more than 86% , it is referred to as ''fuming nitric acid''. Depending on the amount of nitrogen dioxide present, fuming nitric acid is further characterized as red fuming nitric acid at concentrations above 86%, or white fuming nitric acid at concentrations above 95%. Nitric acid is the primary reagent used for nitration – the addition of a nitro group, typically to an organic molecule. While some resulting nitro compounds are shock- and thermally-sensitive explosives, a few are stable enough to be used in munitions and demolition, while others are still more stable and used as pigments in inks and dyes. Nitric acid is also commonly used as a strong oxidizing age ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanuric Acid
Cyanuric acid or 1,3,5-triazine-2,4,6-triol is a chemical compound with the formula (CNOH)3. Like many industrially useful chemicals, this triazine has many synonyms. This white, odorless solid finds use as a precursor or a component of bleaches, disinfectants, and herbicides. In 1997, worldwide production was 160 000 tonnes.Klaus Huthmacher, Dieter Most "Cyanuric Acid and Cyanuric Chloride" Ullmann's Encyclopedia of Industrial Chemistry" 2005, Wiley-VCH, Weinheim. doi 10.1002/14356007.a08 191 Properties and synthesis Properties Cyanuric acid can be viewed as the cyclic trimer of the elusive species cyanic acid, HOCN. The ring can readily interconvert between several structures via lactam-lactim tautomerism. Although the triol tautomer may have aromatic character, the keto form predominates in solution. The hydroxyl (-OH) groups assume phenolic character. Deprotonation with base affords a series of cyanurate salts: : (O)NHsub>3 ⇌ (O)NHsub>2 (O)Nsup>− + H+ (pKa = ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melem
In chemistry, melem is a compound with formula ; specifically, 2,5,8-triamino-heptazine or 2,5,8-triamino-tri-''s''-triazine, whose molecule can be described as that of heptazine with the three hydrogen atoms replaced by amino groups. It is a white crystalline solid. Preparation Melem can be prepared by thermal decomposition of various C−N−H compounds, such as melamine C3N3(NH2)3, dicyandiamide H4C2N4, ammonium dicyanamide NH4 (CN)2 cyanamide H2CN2, at 400 to 450 °C. Structure and properties Crystal structure Melem crystallizes in the group P21/c (No. 14), with parameters a = 739.92(1) pm, b = 865.28(3) pm, c = 1338.16(4) pm, β = 99.912(2)°, and Z = 4. The almost-planar molecules are arranged in parallel layers spaced 327 pm apart. The molecule is in the triamino form, rather than one of the possible tautomers. Thermal decomposition When heated above 560°, melem transforms into a graphite-like C−N material. Melemium cations Melem accepts up to three protons yie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melon (chemistry)
In chemistry, melon is a compound of carbon, nitrogen, and hydrogen of still somewhat uncertain composition, consisting mostly of heptazine units linked and closed by amine groups and bridges (, , , etc.). It is a pale yellow solid, insoluble in most solvents. A careful 2001 study indicates the formula , that consists of ten imino-heptazine units connected into a linear chain by amino bridges; that is, . However, other researchers are still proposing different structures. Melon is the oldest known compound with the heptazine core, having been described in the early 19th century. It has been little studied until recently, when it has been recognized as a notable photocatalyst and as a possible precursor to carbon nitride. History In 1834 Liebig described the compounds that he named melamine, melam, and melon. The compound received little attention for a long time, due to its insolubility. In 1937 Linus Pauling showed by x-ray crystallography that the structure of melon and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Reviews
''Chemical Reviews'' is peer-reviewed scientific journal published twice per month by the American Chemical Society. It publishes review articles on all aspects of chemistry. It was established in 1924 by William Albert Noyes ( University of Illinois). the editor-in-chief is Sharon Hammes-Schiffer. Abstracting and indexing The journal is abstracted and indexed in Chemical Abstracts Service, CAB International, EBSCOhost, ProQuest, PubMed, Scopus, and the Science Citation Index. According to the ''Journal Citation Reports'', the journal has a 2020 impact factor of 60.622. See also * Accounts of Chemical Research ''Accounts of Chemical Research'' is a semi-monthly peer-reviewed scientific journal published by the American Chemical Society containing overviews of basic research and applications in chemistry and biochemistry. It was established in 1968 and th ... References External links * American Chemical Society academic journals Review journals Monthly j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triazines
Triazines are a class of nitrogen-containing heterocycles. The parent molecules' molecular formula is . They exist in three isomeric forms, 1,3,5-triazines being common. Structure The triazines have planar six-membered benzene-like ring but with three carbons replaced by nitrogens. The three isomers of triazine are distinguished by the positions of their nitrogen atoms, and are referred to as 1,2,3-triazine, 1,2,4-triazine, and 1,3,5-triazine. Other aromatic nitrogen heterocycles are pyridines with one ring nitrogen atom, diazines with 2 nitrogen atoms in the ring, triazoles with 3 nitrogens in a 5 membered ring, and tetrazines with 4 ring nitrogen atoms. Uses Melamine A well known triazine is melamine (2,4,6-triamino-1,3,5-triazine). With three amino substituents, melamine is a precursor to commercial resins. Guanamines are closely related to melamine, except with one amino substituent replaced by an organic group. This difference is exploited in the use of guanamine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Amines
In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group (these may respectively be called alkylamines and arylamines; amines in which both types of substituent are attached to one nitrogen atom may be called alkylarylamines). Important amines include amino acids, biogenic amines, trimethylamine, and aniline; Inorganic derivatives of ammonia are also called amines, such as monochloramine (). The substituent is called an amino group. Compounds with a nitrogen atom attached to a carbonyl group, thus having the structure , are called amides and have different chemical properties from amines. Classification of amines Amines can be classified according to the nature and number of substituents on nitrogen. Aliphatic amines contain only H and alkyl substituents. Aromatic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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