Potassium Metaphosphate Research Articles

Alkali Metal Di-tert-butyl Phosphates: Single-Source Precursors for Homo- and Heterometallic Inorganic Phosphate Materials.

The reaction of alkali metal acetates, M(OAc)·nH2O (M = Li, Na, K), with thermally and hydrolytically unstable di-tert-butylphosphate ((tBuO)2PO2H, dtbp-H) in a 1:1 molar ratio in MeOH at room temperature leads to clean formation of group 1 metal phosphates [Li(μ-dtbp)]n (1), [Na(μ-dtbp)]n (2), and [K4(μ-dtbp)4(μ-H2O)3]n (3). All three compounds are essentially M/L 1:1 complexes. Owing to the presence of larger potassium ions, additional coordinated water molecules are found in 3, which has been further employed as a precursor for the synthesis of a mixed-metal phosphate polymer [CaK(μ-H2O)3(μ-dtbp)3]n (4) by reacting 3 with Ca(OAc)2. Compounds 1-4 have been characterized by various analytical and spectroscopic techniques. Molecular structures of 1-4 have been established in the solid state by single-crystal X-ray diffraction studies, which reveal them to be one-dimensional polymers, where the adjacent metal centers are connected through -O-P-O- bridges formed by the dtbp ligand. These complexes are rare examples of analytically pure alkali metal alkyl phosphates bearing no additional N-donor ligands (other than dtbp ligands, only water molecules are coordinated to the metal centers). Therefore, these compounds can be employed as single-source precursors (SSPs) for nano-sized ceramic phosphates. The thermogravimetric analysis of 1-4 reveals the loss of thermally labile tert-butyl substituents of the organophosphate ligands to form organic-free phosphate materials in the temperature range 300-500 °C. Solvothermal decomposition of 1-3 in boiling toluene leads to the formation of corresponding dihydrogen phosphates M(H2PO4) (M = Li, Na, and K). The thermal decomposition of heterometallic 4 in the temperature range 400-800 °C leads to the formation of phase-pure mixed-metal calcium potassium metaphosphate CaK(PO3)3.

Facile Preparation of Cu2+-doped Tin(IV) Pyrophosphate /Potassium Metaphosphate Composite as a Highly Efficient Electrolyte for Intermediate Temperature SOFCs

Facile Preparation of Cu2+-doped Tin(IV) Pyrophosphate /Potassium Metaphosphate Composite as a Highly Efficient Electrolyte for Intermediate Temperature SOFCs

Electrical conductivity of potassium titanyl phosphate KTiOPO4 pure crystals and those doped with Na+, Rb+, and F– ions

KTiOPO4 crystals, both pure and doped with rubidium Rb+ and fluorine F– ions, were grown in temperature range from 1060 to 846°С from salt solvent containing potassium metaphosphate КРО3 and potassium orthophosphate К3РО4 by using a Czochralski modified method. Potassium–sodium titanyl phosphate crystals were obtained from KTiOPO4 crystals by the potassium isomorphic replacement with sodium; to this purpose, sodium chemical diffusion from NaNO3 melt was used. Their ionic conductivity was studied by the electrochemical impedance spectroscopy method. The KTiOPO4 crystal doping with rubidium and sodium ions was shown to lower the conductivity, whereas the doping with fluorine ions results in increased conductivity.

Feasible protein aggregation of phosphorylated poly-γ-glutamic acid derivative from Bacillus subtilis (natto)

Poly-γ-glutamic acid (PGA) was modified with phosphorylating agents such as sodium metaphosphate and potassium metaphosphate in the culture medium of Bacillus subtilis (natto). The highly phosphorylated PGA derivatives were prepared and investigated for their chemical and physicochemical properties. The PGA derivatives had approximately 7% (W/W) inorganic phosphorus and characteristic absorbance PO2− bands at 1082cm−1 and 1260cm−1 by Fourier Transform Infrared Spectroscopy. The derivative modified by sodium metaphosphate (J-5) was easily hydrated in water and had extremely low viscosity. The shear rate-induced transition leading to the decrease of viscosity was not observed in J-5 whereas the derivative modified by potassium metaphosphate (J-6) as well as unmodified PGA (J-1) showed the typical decrease of viscosity. In circular dichroism (CD) measurement of J-5, there was a significant loss of the negative chirality CD signal, implying that protein aggregation occured at decreasing pH from 6.2 to 4.4. The thioflavin T fluorescence intensity of the aqueous solution in the J-5 was extremely high despite the absence of heat-treatment. The results indicate that the J-5 is the likeliest type of aggregation by β-sheet cross-linking which is relevant to protein diseases like Alzheimer’s disease.

On the nature of the KH2PO4 high-temperature transformation

For over two decades, the high-temperature phase transition (HTPT) at around T p = 180 °C on KH2PO4 (KDP), which involves an ionic conductivity increase, constitutes a controversial subject; while most authors ratify a physical transformation (tetragonal → monoclinic phase transition), others defend the chemical transformation. A careful high-temperature phase behavior examination of this acid salt by means of modulated and conventional differential scanning calorimetry, thermogravimetric analysis, simultaneous thermogravimetric and differential scanning calorimetry, impedance spectroscopy, and temperature evolution of X-ray diffraction was performed to provide a possible solution to this long-standing issue. We found that the structural phase transition does not take place. Instead, a chemical transformation occurs at T p. When KDP is heated through this temperature, the sample initially corresponding to a single phase (tetragonal) transforms to a sample composed of two solid phases: tetragonal KDP, located at its bulk, and monoclinic potassium metaphosphate (KPO3), located at its surface. Most of the water produced evaporates, but a small portion of liquid water bonds to KPO3. Because this is of polymeric nature, it takes the role of a host matrix that contains liquid water regions. Consequently, given that part of the water dissolves a portion of surface salt (providing protons), the surface sample system behaves in a similar manner to a polymer electrolyte membrane where the proton transport mechanism includes the vehicle type, using hydronium (H3O+) as a charge carrier. On further heating, the bulk tetragonal KDP phase reduced to its total decomposition. The metastability of the high-temperature phase below T p is also explained.

High-temperature fluxing salt of LiNbO3 single-crystal by potassium meta-phosphate solvent

We report that potassium meta-phosphate (KPO3) is an adequate solvent for high-temperature fluxing salt of LiNbO3 crystal. As the KPO3 is used as the solvent, the solubility of LiNbO3 is as high as 3 g g−1 at 1050 °C. The dissolving is fast. Neither solute nor solvent evaporates from the melt during the dissolving procedure. A clear solution is obtained and verified valid for crystal composition analysis using chemical method of inductively coupled plasma atomic emission spectroscopy. To help for understanding the dissolving mechanism, the obtained fluxing melt product was further characterized using X-ray diffraction, nuclear magnetic resonance and Raman scattering spectroscopy. The results show that the melt is amorphous. The P ion in the melt is in the form of low condensation and the Nb ion is likely in the form of Lindqvist ion. Finally, the dissolving mechanism is discussed.

Recombination of radiation defects and structure of potassium metaphosphate

Recombination of radiation defects and structure of potassium metaphosphate

Technology of obtaining of potassium dihydrophosphate in the system with salting-out

The technology of producing of potassium dihydrophosphate (and potassium metaphosphate) mineral fertilizer in multicomponent system with salting-out is described; this technology is the result of investigation of multicomponent system K+, (C2H5)2NH 2 + // Cl−, H2PO 4 − -H2O, diagrams of the system condition and technological scheme are given; theoretical estimation of useful product yield agrees with experimental data.

Glass Formation and Vibrational Spectra of Glasses in the SrSO4–KPO3–Na2B4O7System

The glass formation region in the SrSO4–Na2B4O7–KPO3 system is determined for the first time. This region occupies 31.8% of the concentration triangle predominantly in the polyphosphate region. The boundary of the glass formation lies along the binary line connecting the sodium tetraborate and potassium metaphosphate regions and reaches compositions with 40 mol % SrSO4. Along the line connecting the potassium phosphate and sodium tetraborate regions, the glass formation at 10 mol % SrSO4 is bounded by the 0.1SrSO4–xNa2B4O7–(0.9 – x)KPO3 join (the Na2B4O7–KPO3 binary join is vitrified completely). From analyzing the IR and Raman spectra, it is assumed that the structure of the glasses under investigation is formed by lattices of two types, namely, the sulfate phosphate and borate lattices.

Low temperature thermal properties of amorphous materials

Abstract

Preparation and properties of macromolecular complexes consisting of [2‐(diethylamino)ethyl]dextran hydrochloride and potassium metaphosphate

AbstractIn aqueous solution [2‐(diethylamino)ethyl]dextran hydrochloride (EA) was reacted with potassium metaphosphate (MPK) to form a series of water‐insoluble macromolecular complexes (MC) at different hydrogen‐ion concentrations (EA–MPK system). EA was also reacted with MPK in the presence of CaCl2 (EA–MPK–CaCl2 system). The structure and properties of MC obtained were compared with each other; elemental analysis, IR spectroscopy, solubilities, thermogravimetric analysis, and scanning electron microscopy were used to characterize these complexes. The molecular structure and properties of each MC were dependent on the hydrogen‐ion concentration and whether the Ca2+ ion coexisted. It was suggested that MC prepared at acidic pH were composed of a relatively loose network including a small quantity of MPK, whereas those prepared at neutral and alkaline pH were composed of a relatively tight network including a large quantity of MPK. This seemed to be due to changes in the degree of dissociation and the conformation of EA and MPK with the hydrogen‐ion concentration. MC in the EA–MPK–CaCl2 system were supposed to have a rather tightly bound network structure due to the Ca2+ ion as compared with those in the EA–MPK system. © 1993 John Wiley & Sons, Inc.

Preparation and properties of macromolecular complexes consisting of chitosan derivatives and potassium metaphosphate

AbstractGlycol chitosan (GC) and methyl glycol chitosan (MGC) were, individually, reacted with potassium metaphosphate (MPK) to form a series of water‐insoluble macromolecular complexes (MC) in aqueous solution at different hydrogen ion concentrations (GC‐MPK and MGC‐MPK systems). GC was reacted with MPK in the presence of CaCl2 (GC‐MPK‐CaCl2 system) as well as in the absence of CaCl2. The properties of MC obtained were studied. On the basis of elemental analysis, solubilities, and thermogravimetry analysis, it is suggested that the molecular structure of each MC depends on the hydrogen ion concentration and whether Ca2+ ion is present or not. MC prepared at pH 1,0 are composed of a relatively loose network including a small quantity of MPK, whereas those MC prepared at neutral and higher pH are composed of a relatively tight network including a large quantity of MPK. As compared with MC in the GC‐MPK system, those in the GC‐MPK‐CaCl2 system are anticipated to have a rather tightly bound network structure due to the cross‐linkings through Ca2+ ions.

Preparation and Properties of Oxynitride Glasses Made from Potassium Metaphosphate

Potassium phosphate oxynitride (KPON) glasses were made by heating crystalline KPO3 at 702° to 775°C in dry ammonia. The softening temperature, thermal expansion coefficient, refractive index, and dissolution rate in water were measured as a function of nitrogen content and compared with the properties of oxynitride glasses made from LiPO3 and NaPO3.

Structure of a molecule of potassium metaphosphate

Structure of a molecule of potassium metaphosphate

Macromolecular Complexes of Potassium Metaphosphate with Cationic Organic Macromolecules

Formation of macromolecular complexes (MCs) of potassium metaphosphate (MPK) with [2-(diethylamino)ethyl]dextran hydrochloride (EA) or glycol chitosan (GC) has been studied. Phase diagrams in three-component system NaBr/acetone/H20 were achieved for M Cs prepared from the MPK-EA system at pH 1.0 and MPK-GC system at pH 1.0 to pH 5.0, but were not achieved in the other reaction systems.The MCs prepared from the, MPK-EA and MPK-GC systems consisted of phosphate and/or metaphosphate with EA and GC, respectively.

Eficiência de vários adubos fosfatados II. Efeito residual

Estudou-se efeito residual de oito fontes de fósforo em dois solos de baixo teor em fósforo, na cultura de milho (Zea mays L.). Os experimentos foram realizados na casa de vegetação. Pela avaliação do peso de matéria seca e quantidade de nitrogênio, fósforo e potássio absorvidos, constatou-se que os fertilizantes com melhor efeito residual foram metafosfato de cálcio e metafosfato de potássio, seguidos por termofosfato e fosforita de Olinda, no regosol. No latosol não se observou diferenças estatisticamente significativas para peso de materia seca, mas de uma maneira geral o metafosfato de cálcio, fosforita de Olinda e metafosfato de potássio foram os melhores. Os fertilizantes com menor efeito residual foram os que contem alto teor em fósforo solúvel em água: superfosfato triplo, superfosfato simples, fosfato diamonico e polifosfato de amonio.

The influence of dissolved heavy water on the internal friction of lithium metaphosphate glasses containing 1% potassium metaphosphate

A batch of very dry lithium metaphosphate glass, containing 1% potassium metaphosphate, was prepared and dissolved completely in nearly pure heavy water. From this solution, a series of glasses with varying deuterium oxide content was prepared. The internal friction and dielectric loss data were taken. The amount of dissolved deuterium oxide was determined from the weight-loss of specimens during heating in vacuum, and checked by means of tritium labeling. It is found that dissolved deuterium oxide influences the internal friction and dielectric losses, in the same was as additions of dissimilar alkali ions do (mixed alkali effect) so that one can say that deuterium behaves similarly to alkali ions. A comparison of the present data with the results of a recent study on the influence of protons on the mechanical and electric properties in an identical host glass illustrates clearly that the mixed alkali effect is not governed by mass differences of the cations.

The influence of dissolved water on the internal friction of lithium metaphosphate glasses containing 1% potassium metaphosphate

A series of lithium metaphosphate glasses, containing different amounts of water, was prepared. The water content was determined from the weight-loss of specimens during heating in vacuum. It is found that dissolved water influences the internal friction and dielectric losses, in the same way as additions of dissimilar alkali ions do. With respect to the physical properties under discussions, one can consider water as an ‘alkali-oxide’. The intermediate temperature peak is increased in magnitude and shifted to lower temperatures with increasing water content. Extrapolation of the present results to the water-free composition shows that the intermediate temperature peak will be absent in the water-free glass.

Cumulative dressings of potassium metaphosphate and soluble PK-fertilizers for seedlings and transplants ofPicea sitchensis in two English nurseries

Cumulative dressings of potassium metaphosphate tested on seedlings and transplants ofPicea sitchensis gave promising results from 1964 to 19661 at two nurseries — a sandy podsol and a sandy loam with better nutrient retention. The four experiments, which also included superphosphate alone, KC1/superphosphate, with and without topdressings of KNO3, and potassium dihydrogen phosphate, were continued until 1969. On the podsol, potassium metaphosphate maintained its superiority for seedlings and also left larger residues in the surface soil. It had no special merit on the sandy loam or for transplants on either soil.

Evaluation of phosphate fertilizers. III. Immediate and residual values of potassium metaphosphate and magnesium ammonium phosphate for potatoes, radishes, barley and ryegrass

SUMMARYTriple superphosphate (21.6% P), potassium metaphosphate (25.0% P) and magnesium ammonium phosphate (19.0% P) were compared as phosphate fertilizers alone and in combination, and as powders and granules, in two experiments on acid soils. Basal nutrients were adjusted to allow for the amounts of N, K, and Mg in the test fertilizers. Immediate effects of the fertilizers were measured by early potatoes and barley, and residual effects by radishes and ryegrass.All powdered fertilizers, alone or in combination, were equivalent to powdered superphosphate for early potatoes. The value of granular fertilizers for potatoes increased with the proportion of superphosphate in the mixtures. Superphosphate equivalents of the granular fertilizers were: magnesium ammonium phosphate, 14%; potassium metaphosphate + magnesium ammonium phosphate, 36%; potassium metaphosphate, 53%; superphosphate + potassium metaphosphate + magnesium ammonium phosphate, 54%; superphosphate + magnesium ammonium phosphate, 60%; superphosphate + potassium metaphosphate, 81%.Residues from powdered fertilizers, applied to potatoes, were equivalent, for radishes, to residues from powdered superphosphate. Residues from granular fertilizers were more effective for radishes than residues from powders.All powdered fertilizers were equivalent to powdered superphosphate for barley cut green. Granular magnesium ammonium phosphate, either alone or mixed with potassium metaphosphate, was slightly less effective than powder.Residues from all powdered fertilizers applied to barley were equivalent for ryegrass. Residues from granular fertilizers, especially potassium metaphosphate and magnesium ammonium phosphate, produced more grass than residues from powders.Apparent recoveries of P by the four crops ranged from 24% to 32% and were more from granules than from powders. Residues from all fertilizers increased 0.5M-NaHCO3-soluble P in soils, and mean yields of ryegrass, the final test crop, increased by 3.2 to 5.1 cwt dry matter/acre/ppm NaHCO3-soluble P in the soils.