Zirconium-containing oxide layers on titanium

The plasma electrolytic deposition (PED) method is shown to be useful for the formation of zirconium-containing layers in electrolytes containing Zr(IV) polyphosphate complexes. Titanium phosphates, binary titanium-zirconium phosphates, titanium phosphates, and zirconium phosphates crystallize during annealing of PED layers in air. The element and phase compositions depend on the molar ratio n=[polyphosphate]/[Zr⁴⁺] in the bulk of the electrolyte.     

Application of thermodynamic‐based retention time prediction to ionic liquid stationary phases

First‐ and second‐dimension retention times for a series of alkyl phosphates were predicted for multiple column combinations in GC×GC. This was accomplished through the use of a three‐parameter thermodynamic model where the analytes’ interactions with the stationary phases in both dimensions are known. Ionic liquid columns were employed to impart unique selectivity for alkyl phosphates, and it was determined that for alkyl phosphate compounds, ionic liquid columns are best used in the primary dimension. Retention coordinates for unknown phosphates are predicted from the thermodynamic parameters of a set standard alkyl phosphates. Additionally, we present changing retention properties of alkyl phosphates on some ionic liquid columns, due to suspected reaction between the analyte and column. This makes it difficult to accurately predict their retention properties, and in general poses a problem for ionic liquid columns with these types of analytes.     

Synthesis of Mixed Alkylphosphites and Alkylphosphates

Some mixed phosphites having two different alkyl chain were obtained as forerunners for mixed phosphates Mixed dialkyl phosphates were obtained in good yields (40-80%) by phase transfer catalysis in liquid-liquid sistem, starting from different dialkyl phosphites and aliphatic alcohols. The reaction conditions were optimized in order to obtain good yields in phosphites and phosphates respectively. Compounds were analyzed by IR, P 31 -NMR.     

Amine Phosphates as Intermediates in the Formation of Open-Framework Structures

Chain, ladder, layer, and three-dimensional metal phosphates were obtained by the reaction of amine phosphates with metal ions under mild hydrothermal conditions. The role of amine phosphates as intermediates in hydrothermal syntheses was corroborated by in situ NMR spectroscopy and X-ray diffraction studies. The picture shows a simple corner-shared linear chain structure formed in the reaction of piperazine phosphate with Zn(II) ions.     

REMOVAL OF PHOSPHATES FROM WATER BY PILLARED RECTORITE

1. INTRODUCTION In recent years, water body eutrophication has become a serious problem. Eutrophication is caused mainly by growth of aquatic plants that are stimulated by dissolved nutrients such as phosphates. Concentrations of TN and TP over the level of cleaning-itself are major indicators for water body eutrophication [1,2]. The presence of trace amounts of phosphate (even less than one ppm) in treated waste water from municipalities and industries is often responsible for eutrophic…     

REMOVAL OF PHOSPHATES FROM WATER BY PILLARED RECTORITE

The presence of trace phosphates in treated wastewater from municipalities and industries is often responsible for eutrophication problems in lakes, rivers, and other water bodies. In this paper,we report the removal of PO43- from water by using a pillared rectorite that we synthesized recently. The results show that cross-linking can significantly increase the adsorbing capacity of Na-rectorite for phosphates. The pH, the concentrations of F, NH4+ and COD are main factors, which affect the results for pillared rectorite to adsorb phosphates from water. The OH-, and F- ions decrease the capacity to adsorb phosphates, while the COD and NH4+ ions increase it.     

磷酸锆催化甘油气相脱水制备丙烯醛

以沉淀法、水热合成法和浸渍法制备了磷酸锆催化剂,通过X射线衍射、热重分析、氮气物理吸附、红外光谱和Hammett指示剂法对催化剂进行了表征,并将该催化剂用于甘油气相脱水反应.研究表明,由沉淀法得到的磷酸锆经过400℃焙烧后能达到最佳催化活性,在温和条件下,甘油可完全转化,丙烯醛选择性为81%,反应24h内催化剂失活不明显.不同方法制备的磷酸锆其结构和表面酸性显著不同,催化剂表面酸性对催化剂活性、丙烯醛选择性和催化剂的寿命均有较大影响.     

Effect of Thermal Treatment on Sorption Activity of Calcium and Magnesium Phosphates

The effect of thermal treatment in the range 20-800°C on the activity of hydrated calcium and magnesium phosphates in recovery of heavy metal ions from aqueous solutions was studied. The composition and sorption properties of materials obtained in all stages of thermal treatment of hydrophosphates and phosphates are considered. The manner in which the sorption activity of phosphates changes upon thermal treatment is interpreted.     

Selective determination of orthophosphate and total inorganic phosphates in detergents by flow injection photometric method

A flow injection photometric system was developed for the determination of orthophosphate and total inorganic phosphates in detergents. While orthophosphate was directly determined in the presence of other phosphates by utilizing the kinetic discrimination of flow injection analysis, total inorganic phosphates was analyzed after on-line hydrolysis of polyphosphates in 2.5 mol l(-1) sulfuric acid for 50 s under 145 degrees C. Sodium dodecyl sulfate (SDS) was added to mask the interference of non-ionic surfactants. The detection limits and the sampling rates were 2.5 mg l(-1) P(2)O(5) and 40 h(-1) for total inorganic phosphates, and 1.0 mg l(-1) P(2)O(5) and 80 h(-1) for orthophosphate determination. The proposed method was applied to analyze orthophosphate and total inorganic phosphates in washing powders. The experimental results are in good agreement with those obtained by the Chinese national standard methods.     

Synthesis and use of glycosyl phosphates as glycosyl donors

Differentially protected glycosyl phosphates prepared by a straightforward synthesis from glycal precursors are used as powerful glycosyl donors. Activation of beta-glycosyl phosphates by TMSOTf at -78 degrees C achieves the selective formation of beta-glycosidic linkages in excellent yields with complete stereoselectivity. Reaction with thiols results in the conversion of glycosyl phosphates into thioglycosides in nearly quantitative yield. An orthogonal coupling strategy using glycosyl phosphate donors and thioethyl glycoside acceptors allows for the rapid synthesis of a trisaccharide.     

Synthetic TRPO<Subscript>4</Subscript> crystals as reference samples in the quantitative X-ray electron probe microanalysis of rare-earth elements

Crystals of 15 rare-earth element phosphates, which provide a set of standard reference samples in X-ray electron probe microanalysis, were synthesized and tested for homogeneity and stoichiometry. The phosphates were synthesized in two stages, the preparation of aqueous phosphates and crystal growth in a solution of potassium polymolybdate K₂Mo₃O₁₀. The tests of the synthesized crystals confirmed their reliability as reference samples.     

Anwendung der Anionenaustauscher-Chromatographie zur Bestimmung geringer Phosphatgehalte

Zusammenfassung Die übliche Methode der papierchromatographischen Trennung und Bestimmung von kondensierten Phosphaten ist in ihrer Anwendung dadurch eingeschränkt, daß zu ihrer Durchführung zweckmäßig Konzentrationen von 1000–5000 mg je Phosphat in 1 l erforderlich sind. Bei Proben, die z.B. im Bereich der Wasserchemie, der Lebensmittelchemie oder der biologischen Chemie in Frage kommen, liegen die gesuchten Phosphatgehalte meist wesentlich niedriger. Eine Konzentrierung durch Eindampfen würde u. a. die Zustandsform der Phosphate infolge Hydrolyse verändern. Zur Bestimmung der verschiedenen Phosphate in diesen Bereichen eignet sich die Anionenaustauscher-Chromatographie. Sie ermöglicht es, ionogen gelöste Phosphate abzutrennen und Hinweise auf die Verteilung von nicht ionogen gelösten anorganischen und organischen Phosphaten zu erhalten. Bis in den Konzentrationsbereich von weniger als 1 mg Gesamt-P₂O₅ im Liter können ionogen gelöste kondenierte Phosphate getrennt und bestimmt werden.In den angeführten Beispielen wurden in phosphatbehandeltem Trinkwasser, in Flußwasser und in Abwasser bis zu 7 verschiedene Zustandsformen von Phosphaten nebeneinander bestimmt: Unter den beschriebenen Arbeitsbedingungen ungelöste Phosphate, nicht ionogen gelöste hochkondensierte anorganische Phosphate und organische Phosphate, und ionogen gelöste Verbindungen (getrennt in Mono-, Di-, Tri-, Trimeta- und hochkondensierte Phosphate).

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Summary The usual method of paper-chromatographic separation and determination of condensed phosphates is limited in its application, because it requires concentrations of 1000 to 5000 mg in 1 l for each phosphate. For samples which are involved e.g. in the field of water chemistry, food chemistry or biological chemistry, the desired phosphate contents are mostly far lower. A concentration by evaporating would change the state of the phosphates by hydrolysis. Anion-exchange chromatography is suitable for the determination of different phosphates in these fields. It permits the separation of ionically dissolved phosphates and allows to obtain information about the distribution of inorganic and organic phosphates not ionically dissolved. Ionically dissolved condensed phosphates can be separated and determined up to a concentration of less than 1 mg of total P₂O₅ per liter.In the examples mentioned above up to 7 different states of phosphates were individually determined in drinking water treated with phosphate, in river water and in waste water: phosphates undissolved under the conditions described, not ionically dissolved high condensed inorganic phosphates and organic phosphates, and ionically dissolved compounds (separated in mono-, di-, tri-, trimeta- and highcondensed phosphates).

     

"Primitive" membrane from polyprenyl phosphates and polyprenyl alcohols

Polyprenyl phosphates, as well as polyprenyl alcohols bearing different isopentenyl C(5) units, have been synthesized. The pH range of spontaneous vesicle formation of polyprenyl phosphates with or without polyprenyl alcohols was defined by fluorescence microscopy. A variety of the acyclic or monocyclic polyprenyl phosphates studied formed stable vesicles in water over a wide range of pHs, and the addition of polyprenyl alcohols allowed the vesicle formation of polyprenyl phosphates at higher pHs. Osmotic swelling of a suspension of unilamellar vesicles using the stopped-flow/light-scattering method enabled us to evaluate the water permeability of polyprenyl phosphate vesicles with or without 10 mol% of free polyprenyl alcohol. The addition of many polyprenyl alcohols to polyprenyl phosphate vesicles decreased the water permeability, and some reduced it even more efficiently than cholesterol.     

Lead(II) Sorption by Magnesium Phosphates

Lead(II) sorption from aqueous solutions by various magnesium phosphates was studied. The sorption kinetics was studied. Magnesium phosphates show high performance in treatment of lead-containing solutions under static and dynamic conditions.     

Development of an ion-pair reversed-phase HPLC method with indirect UV detection for determination of phosphates and phosphites as impurities in sodium risedronate

A method based on RP-HPLC with indirect UV detection was developed for the determination of phosphates and phosphites as impurities in sodium risedronate. RP separation of the phosphates and phosphites was achieved by adding tetrabutylammonium hydroxide as an ion-pairing agent in the mobile phase. Potassium hydrogen phthalate was added to the mobile phase as an ionic chromophore in order to obtain high background absorption of the mobile phase. Separation was performed on a C18 column using a mixture of pH 8.2 buffer (containing 0.5 mM tetrabutylammonium hydroxide and 1 mM phthalate) and acetonitrile (95 + 5, v/v) as the mobile phase, with indirect UV detection at 248 nm. The validation of the method included determination of specificity/selectivity, linearity, LOD, LOQ, accuracy, precision, and robustness. The LOD was 0.86 microg/mL for phosphates and 0.76 microg/mL for phosphites. The LOQ was 2.60 microg/mL for phosphates and 2.29 microg/mL for phosphites. The developed method is suitable for quantitative determination of phosphates and phosphites as impurities in QC of sodium risedronate.     

Chemistry of tetravalent actinide phosphates—Part II

The chemistry and crystal structure of tetravalent cation phosphates, including that of actinides was reviewed several times until 1985. Later, new compounds were synthesized and characterized. In more recent studies it was found that some of previously reported phases, especially those of thorium, uranium, and neptunium, were wrongly identified. In the light of these new facts, an update review and classification of tetravalent actinides phosphates is proposed in this two-part paper. Their crystal structure and some chemical properties are compared to non-actinide cation phosphates.     

Convenient microwave-assisted synthesis of 1-chloroethyl phosphates

An efficient microwave-assisted synthesis of 1-chloroethyl phosphates was developed. Protected vinyl chlorophosphates undergo a fast conversion to the chloroethylidene phosphates in the presence of HCl with excellent yields up to 900 times faster than at the standard NTP conditions.     

Une methode simple de synthese des phosphates terpeniques allyliques primaires et tertiaires

Alkylation of tetrabutylammonium dihydrogenophosphate by terpenic allylic sulphonium salts give the corresponding primary terpenic allylic phosphates in fair to moderate yields, without complex procedures of purification. The catalysis of the reaction by cuprous ion leads to the isolation of tertiary allylic phosphates.     

Sorption of the antitumor drug prospidinum on microgels of polysaccharide phosphates

The intermolecular interaction of prospidinum with gel-forming dextran and starch phosphates has been studied. The sorption equilibria have been studied for cytostatic and the biodegradable hydrogels of polysaccharide phosphates. The concentration coefficients of ion exchange equilibrium and distribution coefficients of prospidinum have been calculated at different degrees of microgel phase filling with the cytostatic, and the relations between the coefficients and the degree of hydrogel swelling have been determined. The ion-exchange and nonexchange contributions to sorption values have been found. The analysis of the distribution coefficients has demonstrated that the concentration of prospidinum sorbed through the nonexchange mechanism is higher than its concentration in an external solution due to the van der Waals interactions between prospidinum cations and macromolecules of polysaccharide phosphates. The Na form of polysaccharide phosphates is the optimal carrier for prospidinum, because this form has a higher density of the total negative charge than their H form has.     

Oligosaccharide synthesis with glycosyl phosphate and dithiophosphate triesters as glycosylating agents

Described is an efficient one-pot synthesis of alpha- and beta-glycosyl phosphate and dithiophosphate triesters from glycals via 1,2-anhydrosugars. Glycosyl phosphates function as versatile glycosylating agents for the synthesis of beta-glucosidic, beta-galactosidic, alpha-fucosidic, alpha-mannosidic, beta-glucuronic acid, and beta-glucosamine linkages upon activation with trimethylsilyl trifluoromethanesulfonate (TMSOTf). In addition to serving as efficient donors for O-glycosylations, glycosyl phosphates are effective in the preparation of S-glycosides and C-glycosides. Furthermore, the acid-catalyzed coupling of glycosyl phosphates with silylated acceptors is also discussed. Glycosyl dithiophosphates are synthesized and are also used as glycosyl donors. This alternate method offers compatibility with acceptors containing glycals to form beta-glycosides. To minimize protecting group manipulations, orthogonal and regioselective glycosylation strategies with glycosyl phosphates are reported. An orthogonal glycosylation method involving the activation of a glycosyl phosphate donor in the presence of a thioglycoside acceptor is described, as is an acceptor-mediated regioselective glycosylation strategy. Additionally, a unique glycosylation strategy exploiting the difference in reactivity of alpha- and beta-glycosyl phosphates is disclosed. The procedures outlined here provide the basis for the assembly of complex oligosaccharides in solution and by automated solid-phase synthesis with glycosyl phosphate building blocks exclusively or in concert with other donors.