Phosphorus Oxoacids Research Articles

Adsorption of Phosphorus Oxoacid on Hydrous Titanium(IV) Oxide in an Aqueous Solution

Abstract The adsorption behavior of phosphorus oxoacid, such as phosphinate, phosphonate, and phosphate, on hydrous titanium(IV) oxide in an aqueous solution was studied in detail. Hydrous titanium(IV) oxide has a pronounced activity for the adsorption of phosphonate and phosphate ions. However, phosphinate ion is little adsorbed on hydrous titanium(IV) oxide. The pH of aqueous solution remarkably affects the adsorption. Amounts of adsorbed phosphonate or phosphate ion from solutions of 500 mg l−1 concentration are about 0.5 mmol g−1 near pH 2. The Langmuir equation, applicable to the adsorption of phosphonate ion, has evaluated the maximum adsorption as being about 0.9 and 0.3 mmol g−1 at pHs 2 and 7, respectively. The heat of adsorption of phosphonate is −5.9 kJ mol −1 at pH 2. The adsorptive activity of hydrous titanium(IV) oxide for phosphonate is suppressed by coexisting ions, such as phosphate and anionic nickel(II) complexes.

Isotachophoretic determination of mobility and p ka by means of computer simulation : III. Evaluation of mobility and p ka of fifteen nucleotides and seven phosphorus oxoacids and their isotachophoretic separation

A computational method was applied for the evaluation of the absolute mobilities ( m o) and p K a values of fifteen 5'-nucleotides and seven phosphorus oxoacids (POAs) from the observed qualitative indices, R E, obtained by isotachophoresis. The nucleotides examined were the sodium salts of AMP, ADP, ATP, CMP, CDP, CTP, GMP, GDP, DTP, IMP, IDP, ITP, UMP, EDP and UTP and the POAs were the sodium salts of hypophosphorous, phosphorous, orthophosphoric, pyrophosphoric, triphosphoric, trimetaphosphoric and tetrametaphosphoric acids. Using the evaluated m o and p K a values, the separability of seven POAs and fifteen nucleotides was assessed by computer simulation. With a leading electrolyte at pH 4.7 buffered by creatinine, the isotachophoretic separation of fifteen nucleotides and pyrophosphate, triphosphate and tetrametaphosphate ions were simulated. This was confirmed by experiments and the simulated calibration characteristics of some POAs were compared with the observed values.

Complex Formation of Monomeric Phosphorus Oxoacids with Sodium Ion in Donnan Exclusion Chromatography

Abstract A method for evaluation of stability constants of very unstable and labile complexes has been proposed by the use of Donnan exclusion chromatography. The stability constants of sodium complexes of monomeric phosphorus oxoacids have been evaluated to be log β1 = -0.04 for phosphinate, log β1 = 0.86 and log β2 = 0.24 for hydrogen orthophosphate and log β1 = 0.61 and log β2 = 0.16 for phosphonate, respectively, at I = 1.00 (CH3)4NCl, t = 25.0° ± 0.1°C.

MECHANOCHEMICAL CHANGE OF TRISODIUM ISOHYPOPHOSPHATE TETRAHYDRATE BY GRINDING

Abstract Mechanochemical change of trisodium isohypophosphate tetrahydrate (P3–O–P5), one of the lower phosphorus oxoacid salts, was investigated by analysis of species of phosphorus oxoanions. On grinding of P3–O-P5–salt, the P–O–P linkages were broken to give phosphonate and pyrophosphate. This shows that the decomposition of P3–O–P5-salt and the recombination of two phosphate radicals produced by grinding, occurred due to grinding.

Separation and quantificaton of various phosphorous oxoacids containing two phosphorus atoms by isotachophoresis

The separation and determination of various phosphorus oxoacids containing two phosphorus atoms, such as 5P—O—5 5P, 3P—O— 5P and 3P—O— 3P salts, by capillary isotachopheresis was investigated. The potential unit (PU) values, which are indicators in quantitative analysis, increased in the order 3P—O— 3P< 3P—O— 5P< 5P—O— 5P. The calibration graphs for these ocoacids were linear in the range 0–10 −7 mole as phosphorus oxoacids. Separation times were approximately 20 min. The procedure was applied to the analysis of some crude products and to the study of the hydrolyticdegradation of some condensed phosphates. The amount f each phosphorus oxoacid could be determined rapidly and easly, and the results were in good agreement with those obtained by ion-exchange chromatography.

Separation and Quantification for Various Phosphorus Oxoacids by Isotachophoresis

Abstract The analytical procedure for the separation and quantification of various phosphorus oxoacids was investigated by the capillary type isotachophoresis. The various phosphorus oxoacids, such as linear-, cyclic-, and lower phosphorus oxoacids, were separated at pH 5.5 with a 0.01 mol dm−3 hydrochloric acid–histidine–0.1% triton X-100 mixture as the leading electrolyte and a 0.01 mol dm−3 hexanoic acid as the terminating electrolyte. The PU value increased in the order of P3m&amp;lt;P4m&amp;lt;P3&amp;lt;P2&amp;lt;\overset1P&amp;lt;\overset3P&amp;lt;P1. The calibration curves for the various phosphorus oxoacids were linear in the range of 0.5–3.5 μg as phosphorus oxoacids. Coefficients of variation for the measured phosphorus oxoacids were less than 2% except for P3. Separation times were approximately 15 min. This procedure was applied to the ground phoshates.

Flow injection system as a post-column reaction detector for high-performance liquid chromatography of phosphinate, phosphonate and orthophosphate

A flow injection system was developed for the rapid flow analysis of lower oxo acids of phosphorus, such as phosphinate and phosphonate. A sodium hydrogen sulphite solution was used as an oxidizing agent for phosphinate and phosphonate, and a strongly acidic solution containing molybdenum(V) and molybdenum(VI) was used as a colour-forming reagent for the resultant orthophosphate. Lower oxo acids of phosphorus can be determined at a sampling rate of 60 samples per h with a relative standard deviation of less than 1%. The flow injection system was found to be useful as a post-column reaction detector for high-performance liquid chromatography of lower oxo acids phosphorus and orthophosphate.

The stability constants of silver complexes of lower phosphorus oxoacids with ring structure

The stability constants of silver complexes of lower phosphorus oxoacids with ring structure

Gel and ion-exchange chromatographic purification of the reaction products between diphosphate and diphosphonate

Gel and ion-exchange chromatographic techniques were applied to the separation of lower oxo acids of phosphorus, ▪ and ▪, produced by the substitution reaction between ▪ (diphosphonate) and ▪ (diphosphate). Sephadex G-25 and Bio-Rad AG1-X8 columns were used. Hydrolysis of ▪ in the process of preparative separation is also discussed.

Lower valent oxo acids of phosphorus and sulfur

Lower valent oxo acids of phosphorus and sulfur

An anion-exchange method for the determination of the ionic charge and the dissociation constant of acid species

An anion-exchange method for determining the average anionic charge of acid species which involve a dissociation equilibrium in solution and for determining their dissociation constants is proposed. This method is based on measurements of the distribution ratio of the acid at a constant internal pH of the anion-exchanger phase. An experiment with ethylenediamine-tetraacetic acid the dissociation behaviour of which is well known indicated that the present method is reliable in studying the solution species. This method was applied to fairly strong acids which can be studied only with extreme difficulty by ordinary potentiometric pH titrations. The first dissociation constants of some oxoacids of phosphorus were successfully determined at 21 ± 1°C: p k 1 = 1.0 ( I = 0.075) for hypophosphoric acid: p k 1 = 0.6 ( I = 0.16), 0.9 (0.05) and 1.7 (0.015) for pyrophosphoric acid, respectively.

Röntgen-Photoelektronenspektroskopie und ihre Anwendung in der Phosphorchemie

Abstract

Chromatography of phosphorus oxoacids

Abstract

Gel chromatographic behavior of the oxo acids of phosphorus

A number of oxo anions of phosphorus which contain one to four phosphorus atoms in the molecule were eluted with potassium chloride solutions on Sephadex columns. The K d values of the oxo anions of phosphorus were measured as functions of the concentration and pH of the eluents, sample concentration and gel prosoity. K d values obtained by both the column and batch method were compared to each other. The main conclusions are as follows. (1) When pure water was used as an eluent, extremely low K d values were observed because of the electrostatic repulsion between the sample anions and the negatively charged gel matrix. (2) The K d values increased with increasing concentration of potassium chloride. This may be due to the variation in the degree of hydration of sample anions. (3) At sample concentrations lower than 10 −2 gram atom P per 1 the elution curves were symmetrical, while unsymmetrical elution curves were obtained at the higher sample concentrations. (4) The K d values did not depend on the pH values of the eluent. (5) The most satisfactory separation of ortho-, di- and triphosphate anions was carried out on a Sephadex G-25 column. (6) The effective sizes of the oxo anions of phosphorus in aqueous solution were stimated from the gel chromatographic data.

Separation of lower oxo acids of phosphorus by paper chromatography

Separation of lower oxo acids of phosphorus by paper chromatography

Separation of lower oxo acids of phosphorus by gradient elution chromatography using an anion exchange resin

A method has been proposed to predict the positions of the elution peaks of some lower oxo acids of phosphorus and orthophosphoric acid in gradient elution chromatography through an anion exchange resin. If the relation between lograrithms of the distribution ratios and of the concentration of ammonium acetate as eluent is linear, one can calculate the position of the elution peak by the method presented here. The calculated positions of the elution peaks of▪ acid agreed approximately with the observed ones. The order of the sorbabilities of phosphate ions is dependent upon the concentrations of ammonium acetate as eluent.

The Reactions of Lower Oxo Acids of Phosphorus with the Molybdenum(V)-Molybdenum(VI) Reagent

Abstract The reaction of twelve lower oxo acids of phosphorus and orthophosphoric acid with the molybdenum(V)-molybdenum(VI) reagent have been carried out under the conditions prescribed by three different procedures : (1) the reactions for 30 min. at room temperature, (2) the reactions for 1 hr. at 95°C, and (3) the reactions in the presence of sodium hydrogen sulfite for 1 hr. at 95°C. The absorption spectra of the reaction products have been measured. It has been found that the blue products obtained by these reactions are orthophosphoric heteropoly blue and/or hypophosphoric heteropoly blue in all cases and that mechanisms of these reactions are closely related to the structural units of the lower oxo acids of phosphorus and their hydrolysis reactions.

The Color Reactions of Lower Oxoacids of Phosphorus with Molybdate and their Application to Colorimetric Determinations of \overset4P–\overset3P–\overset4P– and (–\overset3P–)6–Acid

Abstract The color reactions of twelve lower oxoacids of phosphorus, as well as of \overset5P– and \overset5P–O–\overset5P–acid with molybdate, have been described. Of these compounds, \overset2P–\overset4P, \overset4P–\overset3P–\overset4P– and (–\overset3P–)6–acid react with molybdate in the acid solution to produce a bluish-green color without any reducing agent. The bluish-green color caused by \overset2P–\overset4P–acid is not reproducible. Since the colors caused by \overset4P–\overset3P–\overset4P– and (–\overset3P–)6–acid are stable and since their intensities are proportional to their concentrations, one can detect and determine minute amounts of \overset4P–\overset3P–\overset4P– or (–\overset3P–)6–acid colorimetrically in the presence of the other oxoacids of phosphorus. When both \overset4P–\overset3P–\overset4P– and (–\overset3P–)6–acid are present in a given sample, one can determine each component by combining the method described above with the usual heteropoly blue method for the total phosphorus.

Anorganische Dünnschicht‐Chromatographie. 5. Mitteilung. Dünnschicht‐Chromatographie von Anionen: Phosphate

The thin layer method is applied to the separation and identification of the anions of several oxoacids of phosphorus.