Topic
Phosphotungstic acid
About: Phosphotungstic acid is a research topic. Over the lifetime, 1925 publications have been published within this topic receiving 38059 citations. The topic is also known as: Phosphowolframic acid.
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TL;DR: Electronics and NBO analysis indicate that the terminal N atom of the coordinated N2 molecule in these POM-dinitrogen complexes possesses more negative charge relative to the bridge N atom because Jahn-Teller distorted effects lead to an effective orbital mixture between σ2s* orbital of N2 and d z2 orbital of transition metal center.
Abstract: Molecular geometry, electronic structure, and possible reaction mechanism of a series of mono-transition-metal-substituted Keggin-type polyoxometalate (POM)–dinitrogen complexes [PW11O39M(N2)]n− (M...
16 citations
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TL;DR: In this paper, the synthesis of functionalized benzo[c]chromeno[2,3-a]phenazine derivatives by one-pot, four-component condensation of 2-hydroxynaphthalene-1,4-dione, 1,2-phenylenediamines, aromatic aldehydes, and cyclic 1-3-dicarbonyl compounds has been developed using catalytic amounts of H2SO4 and phosphotungstic acid in EtOH/H2O (1:1) under reflux and
16 citations
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TL;DR: The hydration environments around the heteropolyanion in 12-phosphotungstic acid (PW12O40H3, HPW) were analyzed as a function of temperature in the hexahydrated form (HPW·6H2O).
Abstract: The hydration environments around the heteropolyanion in 12-phosphotungstic acid (PW12O40H3, HPW) were analyzed as a function of temperature in the hexahydrated form (HPW·6H2O). Samples were obtain...
16 citations
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TL;DR: In this paper, tungsten-based heteropolyacids (HPA) were supported on non-ordered mesoporous silica (MSU-x) to increase their dispersion and used as catalysts for glycerol dehydration to acrolein.
16 citations
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14 Jul 1992
TL;DR: In this paper, a compound of the formula (R is H, alkyl or halogen; R is h, aryl or aralkyl) is produced by reacting a phenolic compound with an aliphatic aldehyde or an aromatic aldhyde using a heteropolyacid (e.g. phosphotungstic acid) as an acid catalyst.
Abstract: PURPOSE:To obtain the subject compound without using particular corrosion- resistant reactor by reacting a phenolic compound with an aldehyde in the presence of a heteropolyacid catalyst. CONSTITUTION:A compound of the formula (R is H, alkyl or halogen; R is H, alkyl, aryl or aralkyl) is produced by reacting a phenolic compound with an aliphatic aldehyde or an aromatic aldehyde using a heteropolyacid (e.g. phosphotungstic acid) as an acid catalyst optionally in a solvent (e.g. acetic acid) at 15-120 deg.C. The amounts of the phenolic compound and the heteropolyacid are 2-50mol and 0.001-1mol based on 1mol of the aldehyde, respectively. Heteropolyacid has low corrosivity and stable catalytic activity. It is easily usable and does not cause the lowering of the reaction rate by water produced as a by-product of the reaction. Among the compounds of the formula, the yield of bis(4-hydroxyphenyl)methanes useful to improve the properties of epoxy resins can be selectively increased by the use of heteropolyacid.
16 citations