109 results on '"Hiroyuki Nariai"'
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2. PHOSPHORYLATION OF HYDROXYPROLINE WITH TRISODIUM CYCLO-TRIPHOSPHATE AND EVALUATION OF THEIR MOISTURE RETAINING PROPERTY
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Hideko Maeda, Hiroyuki Nariai, Hirokazu Nakayama, and Saki Tsuchida
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Hydroxyproline ,chemistry.chemical_compound ,Moisture ,chemistry ,Phosphorylation ,General Medicine ,Nuclear chemistry - Published
- 2018
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3. TWO SITES PHOSPHONYLATION OF SALICIN WITH DISODIUM DIPHOSPHONATE IN AQUEOUS SOLUTION
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Aya Moriwaki, Hiroyuki Nariai, Hirokazu Nakayama, and Hideko Maeda
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030207 dermatology & venereal diseases ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Aqueous solution ,Salicin ,chemistry ,010405 organic chemistry ,01 natural sciences ,High-performance liquid chromatography ,0104 chemical sciences ,Nuclear chemistry - Published
- 2016
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4. Transitions from simple electrolyte to polyelectrolyte in a series of polyphosphates
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Hideshi Maki, Kie Ibaragi, Yoshiaki Fujimoto, Minoru Mizuhata, and Hiroyuki Nariai
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chemistry.chemical_compound ,Colloid and Surface Chemistry ,Ion binding ,chemistry ,Supporting electrolyte ,Inorganic chemistry ,Potentiometric titration ,Titration ,Electrolyte ,Degree of polymerization ,Phosphate ,Polyelectrolyte - Abstract
The dependence of polyelectrolyte characteristics on the number of phosphate groups in a series of polyphosphates was clarified by potentiometric titration and 23Na nuclear magnetic resonance using the Donnan model. Ca2+ ion binding to various polyphosphates was consistently inhibited as supporting electrolyte concentration increased. The electrostatic interactions between polyions and counterions, which is peculiar to polyelectrolytes, was enhanced by an increase in the number of phosphate groups. The polyelectrolyte characteristics increased non-monotonically with the number of phosphate groups that constituted the molecules, that is, (1) gradual emergence with three or four phosphate groups, (2) marked strengthening from four to eight phosphate groups, and (3) saturation with eight or more phosphate groups. The characteristics of polyelectrolyte molecules comprising eight or more phosphate groups were independent of the degree of polymerization. These interesting behaviors were observed to be closely similar using two quite different experimental techniques, electrochemical titration and nuclear magnetic resonance.
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- 2015
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5. Multinuclear NMR studies on the effect of electrostatic and hydrophobic interactions on bindings to counterions to weakly acidic and basic polyelectrolytes
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Hideshi Maki, Minoru Mizuhata, Hiroyuki Nariai, and Katsuyoshi Yoshida
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chemistry.chemical_classification ,Chemistry ,Polyacrylic acid ,Inorganic chemistry ,Charge density ,Polymer ,Bjerrum length ,Polyelectrolyte ,Ion ,Hydrophobic effect ,Crystallography ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Counterion - Abstract
23 Na, 35 Cl, 81 Br, and 87 Rb NMR have been applied to clarify the influence of electrostatic and hydrophobic interactions on the counterion binding equilibria of weakly acidic and basic polyelectrolytes with negatively and positively charged polyions, respectively. Na + and Rb + ions capable of binding to weakly acidic polymers (i.e., polyacrylate acid (PAA)), and Cl − and Br − ions capable of binding to weakly basic polymers (i.e., poly(N-vinylimidazole) (PVIm) and polyallylamine (PAAm)) were used as representative examples to measure these interactions. The results revealed that the longitudinal and transverse NMR relaxation rates of the Cl − , Br − and the Rb + counterions in the PVIm and PAA systems were faster than those of free Cl − , Br − and Rb + ions when the polyions were completely neutralized. The binding interactions between the Cl − , Br − and the Rb + ions and PVIm and PAA were found to be hydrophobic in nature because the magnitudes of these effects were found to be dependent on the hydrophobicities of the polyelectrolytes and the counterions. Although a slight hydrophobic interaction was detected between the Rb + ions and PAA, where the degree of neutralization of the polyacid ( α ) was 1, Na + ions also started to bind to PAA at α = 0.65, where the linear charge density corresponded to the Bjerrum length.
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- 2015
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6. PHOSPHORYLATION OF THEANINE WITH CYCLO-TRIPHOSPHATE IN AQUEOUS SOLUTION
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Hideko Maeda, Hitomi Kanazawa, Mae Komatsu, Hiroyuki Nariai, and Hirokazu Nakayama
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- 2015
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7. PHOSPHONYLATION OF INOSINE WITH SODIUM DIPHOSPHONATE IN AQUEOUS SOLUTION
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Hideko Maeda, Yukina Atarashi, Chikako Nakayama, Hiromi Nishida, Hiroyuki Nariai, and Hirokazu Nakayama
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- 2014
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8. 9 Be and 31 P NMR analyses on the influence of imino groups on Be2+ complex stabilities of a series of cyclo-μ -imido triphosphate anions
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Minoru Mizuhata, Hiroyuki Nariai, Hideshi Maki, and Masahiko Tsujito
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NMR spectra database ,Crystallography ,Stability constants of complexes ,Ligand ,Chemistry ,Chemical shift ,Inorganic chemistry ,Molecule ,General Materials Science ,Protonation ,General Chemistry ,Nuclear magnetic resonance spectroscopy ,Tautomer - Abstract
The complexation behaviors of Be²⁺ with cyclo-μ-imido triphosphate anions, cP₃O₉-n(NH)n(3-)n= 1, 2),have been investigated by both ⁹Be and ³¹P NMR techniques at -2.3 °C in order to clarify the coordination structures of the complexes. The spectra showed that cP₃O₉n(NH)n (n = 1, 2) ligands form ML, ML₂, and M₂L complexes with Be²⁺ ions, and the formation of complexes coordinating with nitrogen atoms of the cyclic framework in the ligand molecule has been excluded. These complexation trends are very similar to those of Be²⁺-cP₃O₆(NH)⁻³₃system, which has been reported by us. The peak deconvolution of ⁹BeNMR spectra made these beryllium complexes amenable to stability constant determinations. The stability constants of the complexes increase with an increase in the protonation constants of the ligands as the number of imino groups, which constitute the ligand molecules, is ascended. This increase is primarily attributable to the lower electronegativity of nitrogen atoms than oxygen atoms, which are directly bonded to central phosphorus atoms; moreover, tautomerism equilibrium in the entire of the imidopolyphosphate molecule is also responsible to the higher basicity. ³¹P NMR spectra measured concurrently have verified the formation of the complexes estimated by the ⁹Be NMR measurement. Intrinsic ³¹P NMR chemical shift values of the phosphorus atoms belonging to ligand molecules complexed with Be²⁺ cations have been determined. Not only the protonation constants but also the stability constants of all Be²⁺ complexes increase approximately linearly with an increase in the number of imino groups.
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- 2013
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9. PHOSPHORYLATION OF CITRULLINE WITH CYCLO-TRIPHOSPHATE IN AQUEOUS SOLUTION
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Hideko Maeda, Tomoaki Kita, Takayuki Iiduka, Mitsutomo Tsuhako, Hiroyuki Nariai, and Hirokazu Nakayama
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- 2013
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10. PHOSPHONYLATION OF CATECHIN WITH SODIUM DIPHOSPHONATE IN AQUEOUS SOLUTION
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Hideko Maeda, Yoko Terashita, Tadashi Matsushima, Takeshi Nagai, Mitsutomo Tsuhako, Hiroyuki Nariai, and Hirokazu Nakayama
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- 2012
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11. Protonation Equilibria and Stepwise Hydrolysis Behavior of a Series of Thiomonophosphate Anions
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Hideshi Maki, Yoshiki Ueda, and Hiroyuki Nariai
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Aqueous solution ,Proton ,Series (mathematics) ,Chemistry ,Chemical shift ,Inorganic chemistry ,chemistry.chemical_element ,Protonation ,Sulfur ,Surfaces, Coatings and Films ,Hydrolysis ,Phosphorus atom ,Materials Chemistry ,Physical and Theoretical Chemistry - Abstract
The stepwise protonation constants of a series of thiomonophosphate anions, i.e., monothiomonophosphate, dithiomonophosphate, trithiomonophosphate, and tetrathiomonophosphate anions, were determined by (31)P NMR chemical shift measurements in aqueous solution. Despite the remarkably fast hydrolysis rates of these anions, the protonation processes of all thiomonophosphate anions may be evaluated accurately without any previous purification, because the NMR signals corresponding to thiomonophosphate anions and hydrolyzed residues are well resolved. The stepwise protonation constants decrease with an increase in the number of sulfur atoms bound to the central phosphorus atom. It was revealed that the logarithms of the stabilities of the proton complexes of the series of thiomonophosphate anions decrease "linearly" with an increase in the number of sulfur atoms in the anions. The intrinsic (31)P NMR chemical shifts due to orthophosphate and tetrathiomonophosphate anions show upfield shifts upon successive protonations of the anions, whereas the shifts of mono-, di-, and trithiomonophosphate anions move downfield relative to the anions upon protonation. Furthermore, more asymmetric molecular structures experience greater changes in their X-P-Y bond angles upon protonation or complex formation, leading to drastic changes in the nuclear screening. The symmetry of the molecular structure is related to the direction of the (31)P NMR chemical shift change upon successive protonation of thiomonophosphate anions.
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- 2011
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12. 9Be and 31P NMR analyses on Be2+ complexation with cyclo-tri-μ-imidotriphosphate anions in aqueous solution
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Tohru Miyajima, Hiroyuki Nariai, and Hideshi Maki
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Aqueous solution ,Chemistry ,Ligand ,Chemical shift ,Inorganic chemistry ,chemistry.chemical_element ,Nitrogen ,Spectral line ,Inorganic Chemistry ,NMR spectra database ,Crystallography ,Atom ,Materials Chemistry ,Molecule ,Physical and Theoretical Chemistry - Abstract
Microscopic information on the complexation of Be2+ with cyclo-tri-μ-imidotriphosphate anions in aqueous solution has been gained by both 9Be and 31P NMR techniques at −2.3 °C. Separate NMR signals corresponding to free and complexed species have been observed in both spectra. Based on an empirical additivity rule, i.e., proportionality observed between the 9Be NMR chemical shift values and the number of coordinating atoms of ligand molecules, the 9Be NMR spectra have been deconvoluted. By precise equilibrium analyses, the formation of [BeX(H2O)3]+ and [BeX2(H2O)2]0 (X = non-bridging oxygen donor as a coordination atom in the phosphate groups) has been verified, and the formation of complexes coordinating with the nitrogen atoms of the cyclic framework in the ligand molecule has been excluded. Instead, the formation of one-to-one (ML) complexes, one-to-two (ML2), together with two-to-one (M2L) complexes (L = cP3O6(NH)3) has been disclosed, the stability constants of which have been evaluated as log KML = 3.87 ± 0.03 (mol dm−3)−1, log K ML 2 = 2.43 ± 0.03 (mol dm−3)−2 and log K M 2 L = 1.30 ± 0.02 (mol dm−3)−2, respectively. 31P NMR spectra measured concurrently have verified the formation of the complexes estimated by the 9Be NMR measurement. Intrinsic 31P NMR chemical shift values of the phosphorus atoms belonging to ligand molecules complexed with Be2+, together with the 31P–31P spin–spin coupling constants have been determined.
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- 2011
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13. PHOSPHORYLATION OF CYTARABINE WITH CYCLO-TRIPHOSPHATE IN AQUEOUS SOLUTION
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Hiroyuki Nariai, Takayuki Iiduka, Tomoaki Kita, Mitsutomo Tsuhako, Hirokazu Nakayama, and Hideko Maeda
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chemistry.chemical_compound ,Reaction mechanism ,Chromatography ,Aqueous solution ,chemistry ,Yield (chemistry) ,Citrulline ,Cytarabine ,medicine ,Phosphorylation ,Theanine ,High-performance liquid chromatography ,medicine.drug - Abstract
Phosphorylation of cytarabine has been achieved using inorganic cyclo—triphosphate (P3m) in aqueous solution. The optimum condition for the phosphorylation of cytarabine with P3m is cytarabine : P3m = 1 : 10, pH 12 and 25 °C. Cytarabine 5′–triphosphate, cytarabine 3′–triphosphate, and cytarabine 2′–triphosphate were synthesized with the total yield of more than 75%. The phosphorylated products of cytarabine were stable in neutral and alkaline solution. The reaction mechanism of cytarabine with P3m was discussed.
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- 2010
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14. PHOSPHORYLATION OF POLYAMIDOAMINE DENDRIMERS WITH CYCLO-TRIPHOSPHATE IN AQUEOUS SOLUTION
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Hirokazu Nakayama, Hiroyuki Nariai, Mayumi Matsushita, Hideko Maeda, and Mitsutomo Tsuhako
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inorganic chemicals ,enzymes and coenzymes (carbohydrates) ,PAMAM dendrimer ,Aqueous solution ,Chemistry ,Dendrimer ,bacteria ,Organic chemistry ,Phosphorylation ,macromolecular substances ,environment and public health ,Combinatorial chemistry ,High-performance liquid chromatography - Abstract
Phosphorylation of polyamidoamine dendrimers has been achieved using inorganic cyclo-triphosphate in aqueous solution. In the phosphorylation of polyamidoamine dendrimers, triphosphate derivatives of them were synthesized with the yields of more than 95%. For polyamidoamine dendrimer with four terminal amino groups, two phosphorylated products were obtained.
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- 2009
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15. 各種リン酸セリウムの生成に及ぼす尿素添加効果
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HIROAKI, ONODA, ATSUSHI, TAKENAKA, and HIROYUKI, NARIAI
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Urea addition ,Cerium phosphate ,Thermal synthesis - Abstract
Urea (CO(NH_2)_2) was added in the system of phosphoric acid (H_3PO_4) and cerium carbonate (Ce_2(CO_3)_3・8H_2O), and the system of phosphoric acid and cerium oxide (CeO_2). The thermal behaviors of these dried mixtures were estimated by differential thermal analyses, X-ray diffraction, and Fourier - transform infrared spectroscopy. Furthermore, specific surface area of phosphates was calculated by BET method using nitrogen adsorption. In P/Ce = 1/1, the addition of urea made specific surface area of cerium orthophosphate larger. The formation of tetra-valent cerium phosphates was suppressed by the addition of urea.
- Published
- 2008
16. PHOSPHORYLATION OF D-GLUCOSE AND GLUCO-OLIGOSACCHARIDES WITH DIIMIDO-CYCLO-TRIPHOSPHATE
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Hiroyuki Nariai, Hirokazu Nakayama, Mitsutomo Tsuhako, and Hideko Maeda
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chemistry.chemical_classification ,Chromatography ,Aqueous solution ,Cyclodextrin ,Chemistry ,technology, industry, and agriculture ,Electrolyte ,Maltose ,High-performance liquid chromatography ,carbohydrates (lipids) ,chemistry.chemical_compound ,D-Glucose ,polycyclic compounds ,Phosphorylation ,Organic chemistry ,lipids (amino acids, peptides, and proteins) - Abstract
Phosphorylation of D-glucose has been achieved using inorganic diimido-cyclo-triphosphate in aqueous solution. In the phosphorylation of D-glucose and maltose, 1-O-diimidotriphospho-β-D-glucose and 1-O-diimidotriphospho-β-maltose were stereoselectively synthesized with yields of 35 and 30 %, respectively. For α-cyclodextrin, γ-cyclodextrin, and mono-6-O-α-maltosyl-β-cyclodextrin, two phosphorylated products were obtained in each cyclodextrin and main products were mono-2-O-diimidotriphosphoryl esters of cyclodextrin.
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- 2007
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17. PREPARATION AND REACTIVITY OF CYCLO-HEXAPHOSPHATE COACERVATE
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Katsuyuki Kitano, Hideshi Maki, and Hiroyuki Nariai
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chemistry.chemical_compound ,Coacervate ,chemistry ,Polymerization ,Organic solvent ,Acetone ,Organic chemistry ,Reactivity (chemistry) ,Composition (visual arts) - Abstract
Coacervate using cyclo-hexaphosphate(P6m) was prepared by addition of Ni(NO3)2•6H2O and acetone to cyclo-hexaphosphoric acid solution and investigated for the formation conditions and reactivity. Organic solvents affected the composition of P6m coacervate and a large quantity of organic solvent made P6m more concentrated state. Heptaphosphate(P7) and octaphosphate(P8) having higher degrees of polymerization than P6m were produced in P6m coacervate. P7 and P8 were produced by the reaction of P6m with orthophosphate(P1) and that of P6m with diphosphate(P2), respectively.
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- 2007
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18. Preparation of Various Aluminum Orthophosphates and Condensed Phosphates and their Catalytic Properties
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Hiroyuki Nariai, Hiroaki Onoda, Masakazu Kohno, Jun Tamaki, and Kazuo Kojima
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inorganic chemicals ,chemistry.chemical_classification ,Mechanical Engineering ,Inorganic chemistry ,Phosphate ,medicine.disease ,Decomposition ,Catalysis ,chemistry.chemical_compound ,Acid strength ,Hydrolysis ,chemistry ,Mechanics of Materials ,Modeling and Simulation ,Specific surface area ,medicine ,General Materials Science ,Dehydration ,Ion-exchange resin - Abstract
Aluminum phosphate is useful catalyst for many reactions. There are a lot of reports about catalytic activities of aluminum phosphate, however little reports about the relationship among the preparation, composition, catalytic activity of this phosphate. Phosphates transform to various other phosphates with hydrolysis and dehydration reactions by heating. In this work, some aluminum orthophosphates and condensed phosphates were prepared, and their compositions were estimated. Furthermore, specific surface area, acid strength, the amount of acidic sites, and the catalytic activities for the decomposition of trifluoromethane of these salts were investigated. Aluminum ortho‐ and polyphosphates were prepared in the systems of ortho‐ and poly‐phosphates. The catalytic activity for decomposition of CHF3 was related with a certain degree of specific surface area, acid strength, and the amount of acidic sites. Aluminum orthophosphate with a small amount of sodium cation had higher catalytic activity at lower temperature.
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- 2006
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19. Formation and catalytic properties of various nickel phosphates by addition of neodymium oxide
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Jun Tamaki, Hiroyuki Nariai, Hiroaki Onoda, Takafumi Ohta, and Kazuo Kojima
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Chemistry ,Inorganic chemistry ,chemistry.chemical_element ,Nickel Carbonate ,Liquid nitrogen ,Condensed Matter Physics ,Catalysis ,chemistry.chemical_compound ,Nickel ,Adsorption ,General Materials Science ,Fourier transform infrared spectroscopy ,Phosphoric acid ,Chemical decomposition ,Nuclear chemistry - Abstract
Neodymium oxide was added in the formation systems of various nickel phosphates (orthophosphate, diphosphate, and cyclo-tetraphosphate) from phosphoric acid and basic nickel carbonate. The thermal products were estimated by differential thermal analyses, X-ray diffraction, and Fourier transform infrared spectroscopy. Specific surface areas of phosphates were calculated from the amount of nitrogen gas adsorbed at the temperature of liquid nitrogen by BET method and catalytic activities for decomposition reaction of NF3 were examined. From the obtained results, the influence of the addition of neodymium oxide on formation and catalytic properties of various nickel phosphates was clarified.
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- 2006
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20. Additional effects of rare earth elements on formation and properties of some transition metal pyrophosphates
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Hiroyuki Nariai, Kazuo Kojima, and Hiroaki Onoda
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Mechanical Engineering ,Metals and Alloys ,Analytical chemistry ,Oxide ,chemistry.chemical_element ,Manganese ,Copper ,chemistry.chemical_compound ,Transition metal ,chemistry ,Mechanics of Materials ,Differential thermal analysis ,X-ray crystallography ,Materials Chemistry ,Fourier transform infrared spectroscopy ,Cobalt - Abstract
Transition metal phosphates have been used as inorganic pigments. By the addition of rare earth elements, new functional materials are expected to form. In this work, rare earth oxides (Y 2 O 3 , La 2 O 3 , CeO 2 , and Nd 2 O 3 ) were added in the formation systems of copper, manganese, and cobalt pyrophosphates prepared from ammonium dihydrogenphosphate and the transition metal carbonate. The thermal behaviors of the mixtures of ammonium dihydrogenphosphate, transition metal carbonate, and rare earth oxide were investigated with differential thermal analyses, X-ray diffraction, and Fourier transform infrared spectroscopy. Then, thermal products were estimated by particle size distribution, scanning electron micrographs, specific surface area, ultraviolet-visible reflectance spectra, fluorescence spectra, and acid and base resistance. The influence by the addition of rare earth elements was discussed on the kinds of rare earth elements, transition metals, the M/R ratios, and heating temperatures.
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- 2006
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21. Mechanochemical Effects on the Formation and Properties of Various Nickel Phosphates
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Hiroaki Onoda, Hiroyuki Nariai, Daisuke Mori, and Kazuo Kojima
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Scanning electron microscope ,General Chemical Engineering ,Metals and Alloys ,Analytical chemistry ,Infrared spectroscopy ,chemistry.chemical_element ,Nickel Carbonate ,Ammonium dihydrogen phosphate ,Inorganic Chemistry ,Nickel ,chemistry.chemical_compound ,chemistry ,Differential thermal analysis ,Particle-size distribution ,Materials Chemistry ,Fourier transform infrared spectroscopy - Abstract
Mixtures of ammonium dihydrogen phosphate and basic nickel carbonate with P/Ni molar ratios of 2/3, 1/1, and 2/1 were ground in a planetary mill. The thermal behavior of the milled samples was investigated by differential thermal analysis, x-ray diffraction, and Fourier transform infrared spectroscopy. In addition, the samples were characterized by ultraviolet-visible reflectance spectroscopy, particle size distribution, scanning electron microscopy, and nitrogen adsorption measurements. As a result of mechanochemical effects, the targeted nickel phosphates were formed at lower temperatures, had a more vivid color, and consisted of more regularly shaped particles.
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- 2005
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22. CONVENIENT SYNTHESES AND PHYSICAL PROPERTIES OF VARIOUS CYCLO-DECAPHOSPHATES
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Shouhei Maruishi, Hideshi Maki, and Hiroyuki Nariai
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Materials science - Published
- 2005
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23. Addition of rare earth cation on formation and properties of various cobalt phosphates
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Kazuo Kojima, Hiroaki Onoda, Hiroyuki Nariai, and Kei Yokouchi
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Materials science ,Scanning electron microscope ,Mechanical Engineering ,Inorganic chemistry ,Oxide ,chemistry.chemical_element ,Condensed Matter Physics ,Phosphate ,Pyrophosphate ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,Differential thermal analysis ,Specific surface area ,General Materials Science ,Cobalt ,Cobalt phosphate - Abstract
Various cobalt phosphate pigments were prepared with the addition of rare earth cation by heating the mixtures of ammonium dihydrogenphosphate, cobalt carbonate, and rare earth (Y, La, and Nd) oxide. The thermal behavior of these mixtures was characterized by differential thermal analysis (DTA), X-ray diffraction (XRD), and FT–IR analyses. The thermal products were estimated from scanning electron micrographs (SEM), particle size distribution, specific surface area, UV–vis reflectance spectra, and fluorescence spectra. Furthermore, the acid and base resistance of these materials was evaluated. The thermal reactions were clarified in these systems. Formation of cobalt–neodymium phosphate composite particles were considered from specific surface area. Cobalt pyrophosphate and cyclo -tetraphosphate had more vivid color hue than cobalt orthophosphate. These condensed phosphates had better acid and base resistance. By the addition of rare earth elements, the acidic and basic resistance of cobalt phosphates was remarkably improved.
- Published
- 2005
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24. Temperature dependence on addition of urea and its related compounds on formation of neodymium condensed phosphates
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Hiroaki Onoda, Hiroyuki Nariai, Atsushi Takenaka, and Kazuo Kojima
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chemistry.chemical_compound ,chemistry ,Polyphosphate ,Specific surface area ,Inorganic chemistry ,Urea ,chemistry.chemical_element ,Cyanuric acid ,Phosphate ,Phosphoric acid ,Neodymium ,Biuret test - Abstract
Urea (CO(NH 2 ) 2 ) and its related compounds (biuret: NH(CONH 2 ) 2 and cyanuric acid: (CONH) 3 ) were mixed with phosphoric acid (H 3 PO 4 ) and neodymium oxide (Nd 2 O 3 ). The thermal behavior of these dried mixtures was estimated by differential thermal analyses, X-ray diffraction, and Fourier-transform infrared spectroscopy. Furthermore, specific surface area of phosphates was calculated by BET method using nitrogen adsorption. The addition of urea prevented the crystal growth of Monazite-type NdPO 4 in samples at P/Nd = 2 heated at 450 and 550 °C, and promoted the dehydration–condensation reaction of phosphate. Urea was considered to be decomposed at 400–450 °C in these systems. The decomposition of urea was considered to be related to the formation of neodymium dihydrogenphosphate and then this phosphate transformed to neodymium polyphosphate. The ratio of urea and phosphorus had influence on the promotion of the dehydration–condensation reaction. Thermal behavior of sample added with biuret or cyanuric acid was also investigated.
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- 2005
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25. MECHANOCHEMICAL EFFECTS ON FORMATION AND PROPERTIES OF VARIOUS COPPER PHOSPHATES
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Hiroyuki Nariai, Kazuo Kojima, and Hiroaki Onona
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chemistry ,Inorganic chemistry ,chemistry.chemical_element ,Copper - Published
- 2005
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26. SYNTHESES OF ORGANIC PHOSPHORUS COMPOUNDS WITH -NH-P-NH- AND -NH-P-O- BONDS BY INORGANIC MONOIMIDO-CYCLO-TRIPHOSPHATE
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Hiroyuki Nariai, Mitsutomo Tsuhako, Hideko Inoue, and Hirokazu Nakayama
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Chemistry ,Monoimido-cyclo-triphosphate ,Organic chemistry ,Organic phosphorus - Published
- 2005
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27. Covalent molecular imprinting of bisphenol A using its diesters followed by the reductive cleavage with LiAlH4
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Takashi Ikegami, Toshifumi Takeuchi, Woo-Sang Lee, and Hiroyuki Nariai
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endocrine system ,Bisphenol A ,Clinical Biochemistry ,Biochemistry ,Analytical Chemistry ,chemistry.chemical_compound ,Adsorption ,Phenols ,Benzhydryl Compounds ,Binding site ,Imprinting (psychology) ,Aluminum Compounds ,chemistry.chemical_classification ,Chromatography ,urogenital system ,Hydrolysis ,Esters ,Cell Biology ,General Medicine ,Polymer ,Monomer ,chemistry ,Covalent bond ,Lithium Compounds ,Molecular imprinting ,Oxidation-Reduction ,hormones, hormone substitutes, and hormone antagonists - Abstract
Bisphenol A (BPA) recognition materials were synthesized by a covalent imprinting technique using BPA-dimethacrylate or BPA-diacrylate as the template monomer. Binding sites in the polymers consisted of two hydroxyl groups that are generated by reducing the ester bonds of the template monomer with lithium aluminum hydride. The polymers strongly adsorbed BPA and structurally related compounds, however, other endocrine disruptors were hardly adsorbed. The BPA-dimethacrylate-based polymer interacted with the samples more strongly than the BPA-diacrylate-based polymer.
- Published
- 2004
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28. Bisphenol A-recognition polymers prepared by covalent molecular imprinting
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Hiroyuki Nariai, Toshifumi Takeuchi, Takashi Ikegami, and Takashi Mukawa
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chemistry.chemical_classification ,endocrine system ,Bisphenol A ,Chemistry ,Carboxylic acid ,Ethylene glycol dimethacrylate ,Polymer ,Biochemistry ,Analytical Chemistry ,Hydrolysis ,chemistry.chemical_compound ,Polymerization ,Covalent bond ,Polymer chemistry ,Environmental Chemistry ,Molecular imprinting ,hormones, hormone substitutes, and hormone antagonists ,Spectroscopy - Abstract
A specific recognition material for bisphenol A (BPA) was prepared by using a covalent imprinting technique. A chloroform solution containing bisphenol A dimethacrylate as a template, ethylene glycol dimethacrylate as a cross-linking agent and 2,2′-azobis(isobutyronitrile) as an initiator was polymerized by UV initiation. When BPA was removed from the resulting polymer by hydrolysis of the ester bonds with aqueous sodium hydroxide, carboxylic acid residues were generated in the polymer. After the polymer was packed into a stainless steel column, retention factors of BPA and related compounds were measured. The imprinted polymer adsorbed BPA and structurally related compounds such as 4,4′-dihydroxybenzophenone, bis(4-hydroxyphenyl)sulfone and 4,4′-dihydroxybiphenyl. A typical association constant (Ka) was calculated to be 1.72×105 M−1 by Scatchard analysis. Interestingly, 17α- and 17β-estradiol were also bound to the imprinted polymer (Ka=1.68×105 M−1), indicating that the polymer could be used as artificial receptors for screening the compounds having estrogenic action.
- Published
- 2004
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29. PHOSPHORYLATION OF METHYLAMINE WITH INORGANIC MONOIMIDO-CYCLO-TRIPHOSPHATE
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Taro Eguchi, Hiroyuki Nariai, Hideko Inoue, Hideshi Maki, Mitsutomo Tsuhako, and Hirokazu Nakayama
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chemistry.chemical_compound ,Biochemistry ,Chemistry ,Methylamine ,Monoimido-cyclo-triphosphate ,Phosphorylation - Published
- 2004
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30. Mechanochemical effects on synthesis and properties of manganese–neodymium diphosphates
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Kazuo Kojima, Hiroyuki Nariai, Naomasa Sugino, and Hiroaki Onoda
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Lanthanide ,Scanning electron microscope ,Inorganic chemistry ,Analytical chemistry ,chemistry.chemical_element ,Manganese ,Condensed Matter Physics ,Neodymium ,Adsorption ,chemistry ,Mechanochemistry ,Particle-size distribution ,General Materials Science ,Fourier transform infrared spectroscopy - Abstract
The mixtures of ammonium dihydrogenphosphate, manganese carbonate, and neodymium oxide in the mole ratios of P/(2Mn+3Nd)=1/2 and Mn/Nd=10/0, 9/1 and 8/2 were milled with planetary mill. The thermal behavior of milled samples was investigated with differential thermal analyses, X-ray diffraction, and Fourier transform infrared spectroscopy. Furthermore, thermal products were estimated by ultraviolet-visible reflectance spectra, particle size distribution, scanning electron micrograph, and the amount of adsorbed nitrogen gas. Since the mixed materials were activated as mechanochemical effects, Mn2P2O7 was formed at lower temperature. During mechanical treatment, the change of hue was observed at lower temperature and phosphates had a more vivid tone.
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- 2003
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31. Influence of addition of urea and its related compounds on formation of various neodymium and cerium phosphates
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Atsushi Takenaka, Hiroaki Onoda, Hiroyuki Nariai, and Kazuo Kojima
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Polyphosphate ,Inorganic chemistry ,chemistry.chemical_element ,Condensed Matter Physics ,Biuret test ,chemistry.chemical_compound ,Ammonia ,Cerium ,Dehydration reaction ,chemistry ,Urea ,General Materials Science ,Ammonium ,Cyanuric acid - Abstract
The mixture of rare earth oxide (Nd2O3 or CeO2), phosphorus compound ((NH4)2HPO4 or H3PO4), and an additive (urea: CO(NH2)2, biuret: NH(CONH2)2, cyanuric acid: (CONH)3, or ammonium hydrogencarbonate: NH4HCO3) was heated at 700 °C for 3 h. And then thermal products were analyzed by X-ray diffraction and Fourier transform infrared spectroscopy. In the system of Nd2O3–(NH4)2HPO4, the addition of urea had a little influence on formation of Monazite-type neodymium orthophosphate: NdPO4, polyphosphate: Nd(PO3)3, and ultraphosphate: NdP5O14. In the system of Nd2O3–H3PO4, urea worked as dehydrating agent in a certain region of CO(NH2)2/P ratio to form much P–O–P bonding. Thermal products changed from Monazite-type NdPO4 to Nd(PO3)3 and from Nd(PO3)3 to NdP5O14. The promotion of dehydration reaction was observed only in the system added urea, not in the systems added biuret, cyanuric acid, and ammonium hydrogencarbonate. In cerium salts, Monazite-type Ce(+III)PO4, Ce(+IV)P2O7, Ce(+III)(PO3)3, Ce(+IV)(PO3)4, and Ce(+III)P5O14 were formed without the addition of urea. The addition of urea prevented the formation of tetra-valent cerium phosphates. It was considered that ammonia produced from the decomposition of urea made up a reducing atmosphere and that in this atmosphere Ce(+IV) cation was reduced to Ce(+III) cation.
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- 2003
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32. Mechanochemical effects on synthesis of Rhabdophane-type neodymium and cerium phosphates
- Author
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Hiroaki Onoda, Hiroyuki Nariai, Itaru Motooka, and Hideshi Maki
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Inorganic chemistry ,chemistry.chemical_element ,Condensed Matter Physics ,Phosphate ,Neodymium ,Nitrogen ,Fourier transform spectroscopy ,chemistry.chemical_compound ,Cerium ,Adsorption ,chemistry ,Specific surface area ,General Materials Science ,Spectroscopy ,Nuclear chemistry - Abstract
Mechanochemical effects were investigated in the mixture of a rare earth compound (Nd(NO 3 ) 3 ·6H 2 O, NdCl 3 ·6H 2 O, Nd 2 (CO 3 ) 3 ·8H 2 O, Ce(NO 3 ) 3 ·6H 2 O, CeCl 3 ·7H 2 O, or Ce 2 (CO 3 ) 3 ·8H 2 O) and (NH 4 ) 2 HPO 4 . These mixtures were ground and then heated. These ground mixtures and thermal products were characterized by X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), thermogravimetry–differential thermal analyses (TG–DTA), and adsorption of nitrogen. By grinding, Rhabdophane-type rare earth (Nd or Ce) phosphate was formed in the mixture of Nd(NO 3 ) 3 ·6H 2 O–(NH 4 ) 2 HPO 4 or Ce(NO 3 ) 3 ·6H 2 O–(NH 4 ) 2 HPO 4 . By mechanical treatment, Rhabdophane-type neodymium phosphate was formed at lower temperature in the mixture of NdCl 3 ·6H 2 O–(NH 4 ) 2 HPO 4 . The mixture of CeCl 3 ·7H 2 O–(NH 4 ) 2 HPO 4 indicated XRD peaks of CeO 2 by heating, whereas ground mixtures transformed to Rhabdophane-type cerium phosphate. Specific surface areas of Rhabdophane-type neodymium and cerium phosphates verified from 0.1 to 120 m 2 /g depending on various synthetic conditions. Rhabdophane-type neodymium and cerium phosphates which had large specific surface area were obtained by grinding with ethanol and then heating.
- Published
- 2003
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33. Inconsistency in the Stability Constants of Inorganic Polyphosphate Anions Determined by Potentiometry and Spectroscopy
- Author
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Hideshi Maki, Katsuyoshi Yoshida, Tatsuo Yokota, Hiroyuki Nariai, and Tohru Miyajima
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Aqueous solution ,Ligand ,Polyphosphate ,Metal ions in aqueous solution ,Organic Chemistry ,Inorganic chemistry ,Biochemistry ,Ion ,Inorganic Chemistry ,Metal ,chemistry.chemical_compound ,chemistry ,visual_art ,visual_art.visual_art_medium ,Molecule ,Spectroscopy - Abstract
Compared with cyclo -triphosphate anions, cyclo -tri- w -imidotriphosphate anions (Figure 1), cP 3 (NH) 3 3 m , form stable complexes with transition metal ions. Two experimental procedures, potentiometry and spectroscopy, have been applied to determine the stability constants of the complexes with Co 2+ , Ni 2+ , and Cu 2+ ions at 25°;C and at I = 0.10 (NaClO 4 ). One-to-one (ML) complex formation has been assumed for the analyses. In the presence of sufficiently high concentration of metal ions, the log g 1 values determined by both methods are consistent with each other, whereas the log g 1 value determined by spectroscopy decreases with the decrease in metal ion concentration. This peculiar phenomenon cannot be explained by the presence of additional complexes, that is, ML 2 or M 2 L. One possible reasoning is agglomeration formation of ligand molecules mediated by countercations in aqueous solution.
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- 2002
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34. Formation and catalytic characterization of various rare earth phosphates
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Hiroaki Onoda, Hideshi Maki, Hiroyuki Nariai, Ai Moriwaki, and Itaru Motooka
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Cumene ,chemistry.chemical_compound ,Dehydration reaction ,chemistry ,Inorganic chemistry ,Materials Chemistry ,Dehydrogenation ,General Chemistry ,Fluid catalytic cracking ,Phosphoric acid ,Isomerization ,Butene ,Catalysis - Abstract
Various rare earth phosphates [rare earth elements: R = La, Ce, Pr, Nd, Sm, Yb, and Y; phosphates: Monazite-type, Xenotime-type, Rhabdophane-type, and Weinshenkite-type orthophosphates RPO4, polyphosphate R(PO3)3, and ultraphosphate RP5O14] were synthesized by heating the mixtures of each rare earth oxide and diammonium hydrogenphosphate or phosphoric acid. The compositions of rare earth phosphates were determined by XRD, FT-IR, and TG–DTA. Catalytic properties were studied as one of properties of various rare earth phosphates. Specific surface areas of samples were measured by the BET method. Acid strengths and amounts of acidic sites were measured using several indicators by n-butylamine titration. Acidic properties were also confirmed by adsorption of ammonia. Various rare earth phosphates were characterized by catalytic activities on dehydration reaction of 2-propanol, cracking/dehydrogenation reaction of cumene, and isomerization reaction of butene. The characterization of catalysts was discussed with regard to type of rare earth elements, type of phosphates, and type of phosphorus resources.
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- 2002
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35. Syntheses of various rare earth phosphates from some rare earth compounds
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Hideshi Maki, Itaru Motooka, Hiroyuki Nariai, and Hiroaki Onoda
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Rare-earth element ,Inorganic chemistry ,Oxide ,Condensed Matter Physics ,Phosphate ,Chloride ,Oxalate ,chemistry.chemical_compound ,Crystallinity ,chemistry ,medicine ,General Materials Science ,Sulfate ,Fluoride ,Nuclear chemistry ,medicine.drug - Abstract
Each rare earth compound (rare earth element; R=La, Ce, and Nd, anion; oxide, carbonate, chloride, nitrate, sulfate, oxalate, and fluoride) was mixed with (NH4)2HPO4 or H3PO4 in P/R=1, 3, and 5, and heated in air. The resulting salts were analyzed by TG-DTA, XRD and FT-IR. CePO4·nH2O was not formed in the system of CeO2–H3PO4. However, this phosphate was synthesized in the systems of Ce(NO3)3·6H2O–(NH4)2HPO4, Ce2(CO3)3·8H2O–, CeCl3·7H2O–, and Ce(NO3)3·6H2O–H3PO4. The crystallinity of CePO4·nH2O was high in the systems of CeCl3·7H2O–, and Ce(NO3)3·6H2O–H3PO4. In P/Ce=1, formation of CeO2 was observed in the systems of Ce2(CO3)3·8H2O–, CeCl3·7H2O–, and Ce2(C2O4)3·9H2O–(NH4)2HPO4.
- Published
- 2002
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36. [Untitled]
- Author
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Itaru Motooka, Hideshi Maki, Hiroaki Onoda, and Hiroyuki Nariai
- Subjects
Cerium ,Cerium oxide ,chemistry.chemical_compound ,chemistry ,Phosphorus ,Specific surface area ,Inorganic chemistry ,Urea ,chemistry.chemical_element ,General Materials Science ,Reactivity (chemistry) ,Neodymium ,Biuret test - Abstract
Urea or biuret was added to the thermal synthetic system of Rhabdophane-type neodymium and cerium phosphates. The mixture of a rare earth compound, a phosphorus compound, and an additive [CO(NH2)2 or NH(CONH2)2] was heated at 150°C or 300°C for 20 hr, and the thermal products were analyzed by the XRD, FT-IR, and BET methods. H3PO4 and (NH4)2HPO4 were used for phosphorus compounds, and for rare earth compounds, Nd2O3, Nd(NO3)3 · 6H2O, NdCl3 · 6H2O, Nd2(CO3)3 · 8H2O, CeO2, Ce(NO3)3 · 6H2O, CeCl3 · 7H2O, and Ce2(CO3)3 · 8H2O were used. Urea and biuret worked not only as a dispersing agent but also as a reactant. By the addition of biuret, the thermal products changed from cerium oxide to Rhabdophane-type cerium phosphate in the system using CeCl3 · 7H2O and (NH4)2HPO4. Addition of urea or biuret influenced the specific surface area of Rhabdophane-type neodymium and cerium phosphates. Furthermore, to increase the reactivity of the raw solid materials, mechanical treatment was performed. The mixture of diammonium hydrogenphosphate and a rare earth compound was ground with water and then heated. The influence of the addition of urea or biuret was also studied in these systems.
- Published
- 2002
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37. ⁹Be and ³¹P NMR analyses on the influence of imino groups on Be²⁺ complex stabilities of a series of cyclo-μ-imido triphosphate anions
- Author
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Hideshi, Maki, Masahiko, Tsujito, Hiroyuki, Nariai, and Minoru, Mizuhata
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Anions ,Oxygen ,Magnetic Resonance Spectroscopy ,Nitrogen ,Beryllium ,Phosphorus Compounds ,Ligands ,Phosphorus Radioisotopes - Abstract
The complexation behaviors of Be²⁺ with cyclo-μ-imido triphosphate anions, cP₃O₉-n(NH)n(3-)n= 1, 2),have been investigated by both ⁹Be and ³¹P NMR techniques at -2.3 °C in order to clarify the coordination structures of the complexes. The spectra showed that cP₃O₉n(NH)n (n = 1, 2) ligands form ML, ML₂, and M₂L complexes with Be²⁺ ions, and the formation of complexes coordinating with nitrogen atoms of the cyclic framework in the ligand molecule has been excluded. These complexation trends are very similar to those of Be²⁺-cP₃O₆(NH)⁻³₃system, which has been reported by us. The peak deconvolution of ⁹BeNMR spectra made these beryllium complexes amenable to stability constant determinations. The stability constants of the complexes increase with an increase in the protonation constants of the ligands as the number of imino groups, which constitute the ligand molecules, is ascended. This increase is primarily attributable to the lower electronegativity of nitrogen atoms than oxygen atoms, which are directly bonded to central phosphorus atoms; moreover, tautomerism equilibrium in the entire of the imidopolyphosphate molecule is also responsible to the higher basicity. ³¹P NMR spectra measured concurrently have verified the formation of the complexes estimated by the ⁹Be NMR measurement. Intrinsic ³¹P NMR chemical shift values of the phosphorus atoms belonging to ligand molecules complexed with Be²⁺ cations have been determined. Not only the protonation constants but also the stability constants of all Be²⁺ complexes increase approximately linearly with an increase in the number of imino groups.
- Published
- 2014
38. Synthesis, protonation equilibrium and peculiar thermal decomposition behavior of cyclo-tri-μ-imidotetraphosphate
- Author
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Kazuomi Ryousi, Hiroyuki Nariai, Minoru Mizuhata, and Hideshi Maki
- Subjects
Inorganic Chemistry ,Aqueous solution ,Ligand ,Chemistry ,Chemical shift ,Thermal decomposition ,Inorganic chemistry ,Potentiometric titration ,Molecule ,Protonation ,Medicinal chemistry ,Tautomer - Abstract
The synthesis and isolation of the sodium salt of cyclo-tri-μ-imidotetraphosphate, i.e. Na4cP4O9(NH)3·H2O, were achieved by the hydrolysis of Na4cP4O8(NH)4·2H2O under very weak acidic conditions, i.e. using 0.2 mol L(-1) propionic acid and the pH-controlled recrystallization procedure. The purity of Na4cP4O9(NH)3·H2O was improved from 2% to 95% by the pH-controlled recrystallization only two times. The first protonation constants of a series of cyclo-μ-imidotetraphosphate anions, i.e. cP4O(12-n)(NH)n(4-) (n = 0, 2, 3, 4), were determined by potentiometric titration and (31)P NMR chemical shift measurements in aqueous solution. Regardless of the paucity of the purity of trans-cP4O10(NH)2(4-) anions, the protonation processes of all anions may be evaluated accurately without any previous purification, because the NMR signals corresponding to cP4O(12-n)(NH)n(4-) (n = 0, 2, 3, 4) anions are well resolved. The logarithmic first protonation constants increase with a "linear" increase in the number of imino groups which constitute the ligand molecules. Macroscopic protonation reactions could be divided into three microscopic protonation processes for -O-PO2-O-, -O-PO2-NH-, and -NH-PO2-NH- groups. The basicity of the -NH-PO2-NH- group is especially high, because the delocalization of H(+) ions by lactam-lactim tautomerism on the whole ring molecule of cP3O6(NH)3 and cP4O8(NH)4 enhances the protonation of these ligands. In addition, also the concurrent change observed in the (31)P NMR chemical shift values of the phosphorus nuclei in the -O-PO2-NH- and -NH-PO2-NH- groups of cP4O9(NH)3(4-) anions suggested the effect of the lactam-lactim tautomerism. The intrinsic (31)P NMR chemical shifts for the central phosphorus nuclei for -O-PO2-O-, -O-PO2-NH-, and -NH-PO2-NH- groups show a good proportional relationship with the number of nitrogen atoms bonded to the central phosphorus atoms. Two types of imino groups with mutually dissimilar chemical environments which are present in the Na4cP4O9(NH)3 molecule, that is -O-PO2-NH-PO2-NH- and -NH-PO2-NH-PO2-NH-, brought about a two-stage pyrolytic elimination of imino groups from the initial stage of combustion over a wide temperature range.
- Published
- 2014
39. COMPARISON OF THE COMPLEXATION BEHAVIORS OF TRIPHOSPHATE ANIONS WITH DIIMIDOTRIPHOSPHATE ANIONS
- Author
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Makoto Watanabe, Hideshi Maki, Hiroyuki Nariai, Tetsuji Yamada, Tohru Miyajima, and Makoto Sakurai
- Subjects
Chemistry - Published
- 2001
- Full Text
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40. A 9Be NMR STUDY ON THE COORDINATION STRUCTURES OF Be2+ COMPLEXES WITH CYCLO-μ-IMIDOTRIPHOSPHATE ANIONS (II)
- Author
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Hiroyuki Nariai, Makoto Watanabe, Masahiko Tsujito, Hideshi Maki, Makoto Sakurai, and Tohru Miyajima
- Subjects
Chemistry - Published
- 2001
- Full Text
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41. SYNTHESIS AND SURFACE PROPERTIES OF COPPER AND MAGNESIUM CYCLO-TETRAPHOSPHAIES CONTAINING RARE EARTH ELEMENTS
- Author
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Hiroaki Onoda, Hideshi Maki, Itaru Motooka, and Hiroyuki Nariai
- Subjects
chemistry ,Magnesium ,Metallurgy ,Inorganic chemistry ,Rare earth ,chemistry.chemical_element ,Copper - Published
- 2001
- Full Text
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42. Structure and Organic Gas-Adsorption Properties of Some Polyamine Intercalatedα-Zirconium Phosphates
- Author
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Aki Hayashi, Mayumi Danjo, Tomoko Shimizu, Yukari Yagita, Yukari Mizuguchi, Hiroyuki Nariai, Hirokazu Nakayama, Itaru Motooka, Yumi Kimira, and Mitsutomo Tsuhako
- Subjects
Zirconium ,chemistry.chemical_compound ,Adsorption ,chemistry ,Triethylenetetramine ,Phase (matter) ,Intercalation (chemistry) ,Inorganic chemistry ,Monolayer ,chemistry.chemical_element ,Molecule ,General Chemistry ,Phosphate - Abstract
The intercalation of polyamine into α-zirconium phosphate (α-ZrP) was examined at room temperature and 80 °C. In triethylenetetramine (3E4A), tetraethylenepentamine (4E5A), and pentaethylenehexamine (5E6A) the temperature of the reactions influenced the rate of intercalation, but did not effect the structure of the intercalation compound. On the other hand, the ratios of the constituent phases in the N,N′-bis(3-aminopropyl)-1,3-propanediamine (3P4A) intercalated solid were greatly influenced by the reaction temperature, and two phases with the different interlayer distances could be formed by controlling it. In the phase with an interlayer distance of d = 20 A, obtained predominantly at 80 °C, 3P4A was present as a monolayer of extended molecules in the interlayer region, in which the longitudinal axis of 3P4A was inclined at ca. 60° to the α-ZrP layers. In the phase with d = 17 A, obtained at room temperature, 3P4A existed as a bent form. These polyamine intercalated solids drastically adsorbed acetic ac...
- Published
- 1999
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43. MECHANOCHEMICAL EFFECTS OF SOME RARE-EARTH ULTRAPHOSPHATES AND REFORMING OF THEIR SURFACE FOR CATALYTIC PROPERTIES
- Author
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Itaru Motooka, Hiroyuki Nariai, Hiroaki Onoda, and Hideshi Maki
- Subjects
Chemical engineering ,Chemistry ,Rare earth ,Catalysis - Published
- 1999
- Full Text
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44. THERMAL BEHAVIOR OF LEAD CYCLO-TRIPHOSPHATE
- Author
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Hiroyuki Nariai, Tetsuya Tatsukawa, Hideshi Maki, and Itaru Motooka
- Subjects
Lead (geology) ,Chemistry ,Thermal ,Inorganic chemistry - Published
- 1998
- Full Text
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45. THERMAL PRODUCTS OF SODIUM DIHYDROGENPHOSPHATE-UREA MIXTURES AND LITHIUM CARBON ATE-AMMON IU M DIHYDROGENPHOSPHATE-UREA MIXTURES
- Author
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Hiroyuki Nariai, Akihide Yamamoto, Itaru Motooka, Manabu Hirata, Hiroyuki Sawa, and Atsushi Takenaka
- Subjects
chemistry.chemical_compound ,chemistry ,Sodium ,Inorganic chemistry ,Urea ,chemistry.chemical_element ,Lithium ,Carbon ,Nuclear chemistry - Published
- 1998
- Full Text
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46. MECHANOCHEMICAL EFFECTS ON THE REACTIVITY OF Ni3(PO4)2-(NH4)2HPO4-M2CO3 (M: ALKALINE METAL) MIXTURE
- Author
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Shinji Shibamoto, Hiroyuki Nariai, Hideshi Maki, and Itaru Motooka
- Subjects
Chemistry ,Inorganic chemistry ,Organic chemistry ,Reactivity (chemistry) ,Alkali metal - Published
- 1998
- Full Text
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47. Intercalation of Methylene Blue into Layered Phosphates in the Presence of Butylamine and Function of Alkylamine in the Intercalation Reaction
- Author
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Itaru Motooka, Nobuo Nakamura, Taro Eguchi, Shunro Yamaguchi, Hirokazu Nakayama, Mayumi Danjo, Hiroyuki Nariai, and Mitsutomo Tsuhako
- Subjects
chemistry.chemical_compound ,Crystallography ,chemistry ,Intercalation reaction ,Butylamine ,Bilayer ,Phase (matter) ,Intercalation (chemistry) ,Inorganic chemistry ,Monolayer ,General Chemistry ,Methylene blue - Abstract
The intercalation of methylene blue (MB) into layered phosphates was examined in the presence of butylamine (BA) in order to clarify the mechanism of this reaction and the function of alkylamine, such as BA in the intercalation reaction. MB was not directly intercalated into layered phosphates, but could be intercalated in the presence of BA. The intercalation of MB was strongly influenced by the amount of BA used; that is, it was accelerated by the presence of BA, but inhibited by the presence of too much BA. Moreover, in the procedure which BA was previously intercalated into layered phosphates, it was found that the intercalation of MB can be achieved by removing BA from the interlayer region when BA is formed a monolayer in the phase, and depends on the orientation of BA in the interlayer region when BA forms a bilayer.
- Published
- 1997
- Full Text
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48. [Untitled]
- Author
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Itaru Motooka, Y Fukuma, Hiroyuki Nariai, A. Takenaka, and A Yasuda
- Subjects
Chromatography ,Chemistry ,Ammonium phosphate ,Mechanical Engineering ,Thermal decomposition ,Thermogravimetry ,chemistry.chemical_compound ,Mechanics of Materials ,Sodium hydroxide ,Differential thermal analysis ,General Materials Science ,Ammonium ,Thermal analysis ,Ammonium polyphosphate ,Nuclear chemistry - Abstract
Hexa-ammonium tetraphosphate dihydrate, (NH4)6P4O13·2H2O (HATP), was prepared by the hydrolysis of sodium cyclo-tetraphosphate with sodium hydroxide solution, followed by ion-exchange with ammonium. Thermal decomposition in static air was first carried out dynamically, at a heating rate of 5 K min-1 as used in thermal analysis (thermogravimetric-differential thermal analysis), and also isothermally. To examine the effect of humidity on the thermal decomposition, HATP was heated isothermally in streams of dry and humid air. The products were characterized by X-ray diffraction analysis and high-performance liquid chromatography–flow injection analysis. At 100°C, HATP was decomposed to mono- and triphosphates and to 2 mol diphosphate, and this was accelerated by humidity. Further degradation of the triphosphate to mono- and diphosphates took place slowly. The 2 mol diphosphate also decomposed slowly to 4 mol monophosphate. At temperatures above 150°C, the form I of ammonium polyphosphate (I-APP) was produced. I-APP was further hydrolysed by humidity to shorter-chain phosphates, such as mono-, di- and triphosphates.
- Published
- 1997
- Full Text
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49. Preparation and Chemical Properties of a Novel Layered Cerium(IV) Phosphate
- Author
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Mayumi Danjo, Hiroyuki Nariai, Yoshinobu Baba, Mitsutomo Tsuhako, Masahiko Murakami, and Itaru Motooka
- Subjects
Cerium(IV) oxide–cerium(III) oxide cycle ,Thermogravimetry ,Zirconium ,Cerium ,chemistry.chemical_compound ,chemistry ,Differential thermal analysis ,Vapour pressure of water ,Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,Phosphate ,Phosphoric acid - Abstract
A synthetic method of a novel cerium(IV) bis(hydrogenphosphate) dihydrate, Ce(HPO4)2·2H2O, hereafter referred to as CeP·2H2O, has been established by the hydrothermal reaction of cerium(IV) oxide with phosphoric acid in an autoclave. The preparation of CeP·2H2O was significantly affected by the reaction conditions: the mixing ratio (P2O5/CeO2) of CeO2 and phosphoric acid, heating temperature and time, and water vapor pressure. The optimum condition for the preparation of CeP·2H2O was the mixing ratio of 1.5—2.0, heating temperature 175—200 °C, heating time 5 h, and water vapor pressure 5.0—7.0 atm. The results of X-ray powder diffraction, fluorescent X-ray analysis, differential thermal analysis and thermogravimetry (DTA-TG), IR spectrum, and phase transition showed that CeP·2H2O is a novel crystalline layered cerium(IV) phosphate having a interlayer distance d = 18.0 A, longer than any layered phosphates (zirconium(IV), titanium(IV), and tin(IV) phosphates) so far reported. The reversible phase transitio...
- Published
- 1997
- Full Text
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50. SYNTHESES AND THERMAL BEHAVIORS OF SOME CATION-MIXED CYCLO-PHOSPHATES
- Author
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Itaru Motooka, Hiroshi Matsukizono, Hiroyuki Nariai, and Hideshi Maki
- Subjects
Chemistry ,Thermal ,Polymer chemistry - Published
- 1996
- Full Text
- View/download PDF
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