- High pressure behaviour of KHSO4 studied by electrical impedance spectroscopy
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Measurements of the electrical conductivity were performed in KHSO 4 at pressures between 0.5 and 2.5 GPa and in the temperature range 120-350 °C by the use of the impedance spectroscopy. The temperatures of the α-β phase transition (TTr) and of the melting (T m), determined from the Arrhenius plots ln(σT) vs. 1/T, increase with pressure up to 1.5 GPa having dT/dP～+45 K/GPa. Above the pressure 1.5 GPa, the pressure dependencies of TTr and Tm are negative dT/dP～-45 K/GPa. At pressures above 0.5 GPa, the reversible decomposition of KHSO4 into K3H(SO4) 2+H2SO4 (and probably into K5H 3(SO4)4+H2SO4) affects the electrical conductivity of KHSO4, with the typical values of the protonic electrical conductivity, c. 10-1 S/cm at 2.5 GPa.
- Bagdassarov,Lentz
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- A study of molecular motion and Raman processes in K3H(SO 4)2 and KHSO4 single crystals by observation of 1H and 39K spin-lattice relaxation
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The spin-lattice relaxation rates for 1H and 39K nuclei in K3H(SO4)2 and KHSO4 single crystals, which are potential candidate materials for use in fuel cells, were determined as a function of temperature. The spin-lattice relaxation recovery of 1H can be represented for both crystals with a single exponential function, but cannot be represented by the Bloembergen-Purcell-Pound (BPP) function, so is not related to HSO4 motion. The recovery traces of 39K, which predominantly undergoes quadrupole relaxation, can be represented by a linear combination of two exponential functions. The temperature dependences of the relaxation rates for 39K can be described with a simple power law T1-1=αT 2. The spin-lattice relaxation rates for the 39K nucleus in K3H(SO4)2 and KHSO4 crystals are in accordance with a Raman process dominated by a phonon mechanism.
- Lim, Ae Ran,Jung, Won Ki,Han, Tae Jong
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- Comparative thermoanalytical investigation of the cross-linking behaviour of three different paraffin waxes in the presence of potassium persulphate
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The cross-linking of three different paraffin waxes - a hard oxidised wax, a medium wax, and a hard wax with narrow molar mass distribution - in the presence of potassium persulphate (PPS) was investigated thermoanalytically. DSC and TG curves for untreated waxes and waxes treated with different amounts of PPS were obtained and the observations were compared with gel content data obtained through gravimetric analysis. Although initial indications were that cross-linking did occur, reheat curves of wax/PPS mixtures as well as gel content data showed that no cross-linking occurred. It was, however, found that PPS most probably decomposed into KHSO4 and that this decomposition gave rise to functionalisation of the waxes.
- Luyt,Ishripersadh,Timm
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- Mechanochemical Decomposition of Dipotassium Peroxodisulfate by Dry Grinding
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The mechanochemical decomposition of dipotassium peroxodisulfate by dry grinding was investigated by X-ray diffractometry, infrared spectrophotometry, electron spin resonance (ESR) spectrometry, and thermal and volumetric analyses.When dipotassium peroxodisulfate (K2S2O8) was ground, type I of K2S2O8 was transformed into type II and then into type III.With prolonged grinding, the O-O linkage in K2S2O8 was severed to produce KSO4 radicals, which reacted with a little moisture to give KHSO4.
- Motooka, Itaru,Nariai, Hiroyuki,Tsuhako, Mitsutomo
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- Superionic phase transition in KHSO4: A temperature-dependent raman investigation
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Temperature-dependent Raman spectroscopic studies have been carried out on KHSO4 single crystals in the temperature range 298-493 K. A structural phase transition driven by the lattice and molecular disorder is observed at 473 K. The spectral data enable an understanding of the nature of the lattice disorder across the phase transition leading to the superionic phase. The disorder in the HSO4- polymeric hydrogen-bonded chain leading to a higher symmetry in the high temperature phase is clearly captured from our Raman results. The internal S-OH and S-O stretching modes and, to a limited extent, the external modes throw light on the disorder mechanism and the enhancement of conductivity after transition.
- Swain, Diptikanta,Bhadram, Venkata Srinu,Pradhan, Gopal K.,Bhat, S. Venkataprasad,Narayana, Chandrabhas,Rao
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- Synthesis, crystal structure, and vibrational spectra of M 4V2O3(SO4)4 (M = K, Rb, Cs)
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Synthesis was performed and physicochemical properties were studied for the M4V2O3(SO4)4 complexes, where M = K, Rb, or Cs. Their crystal structures were determined using the set of data from X-ray diffraction and neutron diffraction studies. All compounds crystallize in a triclinic lattice (space group P1, Z = 2) with the parameters: a = 7.7688(2), 7.8487(1), 8.1234(1) ?; b = 10.4918(3), 10.8750(2), 11.1065(1) ?; c = 11.9783(4), 12.1336(2), and 11.8039(1) ?; α = 76.600(2)°, 77.910(1)°, 79.589(1)°; β = 75.133(2)°, 75.718(1)°, 87.939(1)°; γ = 71.285(2)°, 72.189(1)°, 75.567(1)°; V = 881.78(5), 945.42(3), 1014.34(2) ?3 for K, Rb, Cs, respectively. The structure of M4V2O 3(SO4)4 was found to be formed by discrete complex anions V2O3(SO4) 4 4- incorporating two oxygen-bridged vanadium atoms in a distorted octahedral oxygen environment. The sulfate groups are coordinated by the vanadium atoms in the chelating mode with a large scatter of S-O interatomic distances and OSO angles. Every VO6 octahedron has a short terminal vanadium-oxygen bond with a length of about 1.6?. The V2O 3(SO4) 4 4- complex anions in potassium and rubidium compounds differ from that in Cs4V 2O3(SO4)4 in the type of symmetry and mutual spatial orientation. The vibrational spectra were presented and interpreted in line with the structural analysis data.
- Krasil'Nikov,Tyutyunnik,Zubkov,Berger,Perelyaeva, L. Ya.,Baklanova
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p. 491 - 500
(2011/08/08)
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- Phase ratios in the K2O-V2O4-SO 3 system at high sulfur trioxide concentrations
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Phase ratios in the three-component oxide system K2O-V 2O4-SO3 in the region of the sulfur trioxide concentrations corresponding to its concentrations in the active component of vanadium catalysts for SO2/
- Krasil'nikov
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p. 258 - 262
(2008/10/09)
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- Reaction of graphite with sulfuric acid in the presence of KMnO4
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The reaction of graphite with sulfuric acid in the presence of KMnO 4 (oxidant : graphite ratio 0.027-0.55) involves consecutive and concurrent reactions: graphite intercalation and direct oxidation of the carbon matrix. The properties of graph
- Sorokina,Khaskov,Avdeev,Nikol'skaya
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p. 162 - 168
(2007/10/03)
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- Method for preparing metal cyanide catalyst complexes using partially miscible complexing agents
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Double metal cyanide catalysts (DMC) are complexed with complexing agents that are miscible in poly(propylene oxide) at higher temperatures and immiscible at lower temperatures. The complexing agent is a poly(ethylene oxide) polymer or a copolymer having a poly(ethylene oxide) block. The catalyst is easily removed from a polyether polyol.
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- Potassium Hydrogensulfate Dihydrogensulfate, K(HSO4)(H2SO4) - Synthesis and Crystal Structure
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Single crystals with the composition KH3(SO4)2 have been synthesized from the system Potassium sulfate/sulfuric acid. The hitherto crystallographically not investigated compound crystallizes in the monoclinic space group P21/C (14) with the unit cell parameters a=7.654(3), b=11.473(5) and c=8.643(3) A, β=112.43(3)°, V=701.6 A^3, Z=4 and Dx=2.22 g.cm^-3. The structure contains two types of tetrahedra, SO3(OH) and (SO2(OH)2). These tetrahedra form tetramers via hydrogen bonds consisting ofboth, two SO3(OH) and SO2(OH)2 tetrahedra. The tetramers are linked to each other via hydrogen bonds. Potassium is coordinated by 9 oxygen atom s which belong to both kinds of tetrahedra. These potassium oxygen polyhedra are connected by common faces forming chains running parallel z.
- Kemnitz, E.,Werner, C.,Worzala, H.,Trojanov, S.
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- Substituted tyrosyl diamide compounds
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The present invention provides substituted tyrosyl diamide compounds of general Formula I: STR1 and the pharmaceutically-acceptable salts thereof, which are useful for inducing analgesia in animals, pharmaceutical compositions comprising a pharmaceutically-acceptable carrier and a compound of Formula I, and a method for inducing analgesia in an animal in need thereof comprising administering a therapeutically-effective amount of a compound of Formula I to the animal.
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- PHOSPHORUS-CONTAINING HMG-COA REDUCTASE INHIBITORS, NEW INTERMEDIATES AND METHOD
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Compounds which are useful as inhibitors of cholesterol biosynthesis and thus as hypocholesteroleumic agents are provided which have the structure STR1 wherein R is OH, or salts thereof or lower alkoxy; R. sup.x is H or alkyl;X is--CH 2--,--
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- Fluorine-substituted cyclohexylcyclohexene derivative
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A compound represented by formula (I): STR1 wherein R represents a straight chain alkyl group having from 1 to 9 carbon atoms; STR2 represents STR3 represents a hydrogen atom or a fluorine atom; and STR4 has a trans (equatorial-equatorial) configuration, is disclosed. The compound of formula (I) exhibits a nematic phase in the vicinity of room temperature or in a temperature range higher than room temperature and has a small optical anisotropy and a positive dielectric anisotropy and is, therefore, useful in preparing a liquid crystal display cell excellent in viewing-angle characteristics.
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- Molten Potassium Pyrosulfate: Reactions of Lanthanum Metal and Six of its Compounds
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The reactions of lanthanum metal, La2O3, La(OH)3, La(NO3)3.6H2O, La2(CO3)3.3H2O, LaCl3 and LaCl3.7H2O with molten K2S2O7 were studied.The metal reacted with K2S2O7 to produce La2(SO4)3, K2SO4 and SO2.Lanthanum(III) oxide was converted into La2(SO4)3, as were La(OH)3, La(NO3)3.6H2O, La2(CO3)3.3H2O, LaCl3 and LaCl3.7H2O but with the evolution of H2O, NO2+O2+H2O, CO2+H2O, Cl2+SO2+S and Cl2+SO2+H2O+HCl respectively.K2S2O7 was converted into K2SO4 in the reactions.Reaction pathways have been suggested to explain the final products.The temperatures and stoichiometries of the reactions have been established.
- Mineely, Patric J.,Tariq, Shabbir A.
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p. 1309 - 1314
(2007/10/02)
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- REACTION OF THE ACTIVE COMPONENT OF VANADIUM SULFATE CATALYST WITH WATER VAPOR.
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In order to understand the processes leading to the chemical degeneration of the active component of vanadium sulfate catalyst in moist air and to the corresponding deterioration of their performance parameters, it is necessary first of all to study the reaction of potassium oxosulfatovanadates (IV) and (V) with water vapor. In this work we consider the conversions of potassium oxosulfatovanadates (V) and (IV), type SVS and SVD industrial vanadium catalysts, and glasses of the K//2S//2O//7-V//2O//5-V//2O//4 system in an atmosphere saturated with water vapor at room temperature. The investigation has showed convincingly that by reaction with water vapor the active component of the catalysts undergoes substantial changes, which in turn change their physicochemical properties and may be the reason for the decrease in catalytic activity and mechanical strength.
- Krasil'nikov,Ivakin,Manaeva,Malkiman
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p. 1360 - 1364
(2008/10/08)
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- Plant-protective and pest-control agent
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A herbicidal composition capable of preventing weed growth of potatoes or soybean plants consists of a triazene or an aromatic nitro compound together with an inorganic salt, especially sodium bisulfate or potassium bisulfate which reduced the quantity of the organic herbicide below that usually required to obtain a corresponding herbicidal effect and hence prevents phytotoxic damage. The composition contains 0.1:1 to 15:1 parts by weight of the inorganic compound to the organic compound and is applied in an amount of 0.1 to 30 kg of the composition per hectare.
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