Double phosphate crystallization in phosphate liquids

The discussion concerns the interactions of oxides of metals in groups III–VIII not with individual molten phosphates but with mixtures of them, which provides a range in M₂O:P₂O₅ in the phosphate liquid from 0.5 to 2.0; this constitutes a new approach to these reactions, and it enables one to determine unambiguously the ranges in which double phosphates are formed and to define the conditions under which the individual crystals are produced from those liquids.Kiev University. Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 27, No. 3, pp. 307–311, May–June, 1991. Original article submitted February 19, 1991.     

Anilinium dihydrogen phosphate

The triclinic structure of the title compound, C₆H₈N⁺·H₂PO₄⁻, with three symmetry‐independent structural units (Z′ = 3), is formed of separate organic and inorganic layers alternating along the b axis. The building blocks of the inorganic layer are deformed H₂PO₄ tetrahedra assembled into infinite ladders by short and hence strong hydrogen bonds. The anilinium cations forming the organic layer are not hydrogen bonded to one another, but they are anchored by four N—H...O crosslinks between the dihydrogen phosphate chains of adjacent ladders. Two H atoms of each –NH₃ group then form one normal and one bifurcated N—H...O hydrogen bond to the P=O oxygens of two tetrahedra of one chain, while the third H atom is hydrogen bonded to the nearest O atom of an adjacent chain belonging to another dihydrogen phosphate ladder.     

Na-Gd phosphate glasses

Summary The present paper deals with preparation, thermal properties and radioluminescence of Ce-doped Na-Gd phosphate glasses. Thanks to their high radioluminescence intensity, three times greater than that of BGO, these glasses are promising materials for the detection of neutrons, - and X-rays. The glasses with a Gd concentration up to 89 mol% were prepared by a rapid quenching technique in air. Their thermal properties were determined using DSC and temperatures of glass transition were measured in addition using TMA. Temperatures of glass transition, crystallization and melting depend on Gd concentration and they follow the liquidus line in a phase diagram of binary system in which two eutectics and a congruently melting compound exist. High glass-forming ability of this glass system was found evidenced. The glasses containing at least 30 mol% Gd were moisture resistant.     

Photo-oxidation of phenol over titania pillared zirconium phosphate and titanium phosphate

The photodegradation of phenol was studied in the aqueous solutions over titania pillared zirconium phosphate and titanium phosphate under solar radiation and compared with that of the UV-radiation (6 W low pressure Hg vapor lamp). This reaction was studied by varying different parameters such as catalyst dose, initial phenol concentration, pH of solution and irradiation time. The degradation rate of phenol was favourable under neutral pH condition. The degradation process approximately obeyed first-order kinetics with apparent rate of degradation constant increasing with decreasing the initial phenol concentration.     

Production of condensed phosphate by plasma chemical treatment of phosphate raw material

Thermodynamic calculations and experimental studies have demonstrated that dissociation of natural phosphates in a low-temperature plasma involves partial calcium oxide evaporation. As a result, upon cooling gaseous products of the dissociated phosphate raw material, compounds containing condensed calcium phosphate are formed. The composition and properties of condensed calcium phosphates, which can be used as fertilizers, are discussed.     

Anodic electrodeposition of highly oriented zirconium phosphate and polyaniline-intercalated zirconium phosphate films

Films of highly oriented alpha-zirconium phosphate and polyaniline-intercalated zirconium phosphate with controllable thickness in the micrometer range were grown anodically on Pt electrodes. To optimize the electrodeposition conditions, the exfoliation of alpha-zirconium phosphate by tetrabutylammonium (TBA) salts was investigated in several nonaqueous solvents. Acetonitrile was found to be the best solvent for making crack-free, oriented films because of its high vapor pressure, low viscosity, and relatively high permittivity. With TBA salts of neutral or weakly acidic anions (TBACl, TBABr, TBAI, TBA(HSO4), or TBA(H2PO4)), full exfoliation did not occur and alpha-zirconium phosphate and/or polyaniline were deposited as rough films. With basic anions (TBAF or TBAOH), dense, adherent films were obtained. X-ray diffraction patterns of the films showed that they were highly oriented along the stacking axis. The thickness could be controlled, up to about 40 microm, by limiting the time of the electrodeposition reaction. At monomer concentrations below 1.0 x 10(-2) mol/dm3, the emeraldine form of the intercalated polymer was obtained. Electrodeposition thus provides a thick film alternative to layer-by-layer assembly for intercalation compounds of alpha-zirconium phosphate with a conducting polymer.     

Codeine dihydrogen phosphate hemihydrate

The cation of the title structure [systematic name: (5α,6α)‐6‐hydroxy‐7,8‐didehydro‐4,5‐epoxy‐3‐methoxy‐17‐methylmorphinanium dihydrogen phosphate hemihydrate], C₁₈H₂₂NO₃⁺·H₂PO₄⁻·0.5H₂O, has a T‐shaped conformation. The dihydrogen phosphate anions are linked by O—H...O hydrogen bonds to give an extended ribbon chain. The codeine cations are linked together by O—H...O hydrogen bonds into a zigzag chain. There are also N—H...O bonds between the two types of hydrogen‐bonded units. Addditionally, they are connected to one another via O...H—O—H...O bridging water molecules. The asymmetric unit contains two codeine hydrogen cations, two dihydrogen phosphate anions and one water molecule. This study shows that the water molecules are firmly bound within a complex three‐dimensional hydrogen‐bonded framework.     

Potassium europium molybdate phosphate

The new compound K₂Eu(MoO₄)(PO₄) has been synthesized. The compound is isostructural to the known potassium lanthanide molybdate phosphates (Ln = Nd, Sm, Dy, Yb, Lu). It crystallizes in space group Ibca (no. 73) with the unit cell parameters a = 19.734 Å b = 12.301 Å c = 6.978 Å V = 1693.8 Å, R _p = 2.19%, R _wp = 2.97%. K₂Eu(MoO₄)(PO₄) decomposes above 1000°C and has a rather high luminescence intensity. The ⁵D₀-⁷F_2,4 electric dipole transitions are noticeably stronger than the ⁵D₀-⁷F_1,3 magnetic dipole transitions because of the noncentrosymmetric coordination environment of the europium ions in the complex molybdate phosphate.     

Hydrogen bonded phosphate structures

Abstract

Some phosphate esters form structures containing infinite chains of hydrogen bonded units, others form discrete dimeric units, and still others form columns or chains of dimeric units. We have formed unique hydrogen bonded phosphorus ester systems which incorporate catechol molecules of crystallization, [HOC₆H₄OP(Ph)O₂][PPh₄]· catechol, 1, and [HOC₆H₄OP(Ph)O₂] [C₅H₅NH]· catechol, 2. X-ray analysis shows a chain arrangement in 1 and dimeric phosphonate units in a chain structure for 2 By comparing our results with literature examples, a classification of hydrogen bonding in phosphates results which proves useful in interpreting orientational influences at enzyme active sites.     

Vinyl phosphate choline analogs

Conclusion The alkylation of trimethylamine by O-phosphorylated allyl chloride gave a new type of choline phosphate, namely, a vinylcholine phosphate. The thermal dealkylation of this product gave a phosphorus-containing betaine.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khitnicheskaya, No. 10, pp. 2333–2334, October, 1986.     

Iron-substituted tricalcium phosphate ceramics

Porous iron-substituted tricalcium phosphate (FeTCP) ceramics with a Fe content of 0.49 and 1.09% has been developed. The hydrostatically estimated ceramics porosity is 40–45%. The solubility of ceramics in an isotonic solution has been studied. The solubility rate of FeTCP ceramics is slightly higher as compared with iron-free ceramics. Based on the results of in vitro tests of FeTCP ceramics on cultured fibroblasts, these materials are believed to be biocompatible. The developed materials can be recommended for use in medicine in the treatment of diseases associated with bone lesions.     

Phosphoesterase activity and phosphate release from tributyl phosphate by aCitrobacter sp.

Tributyl phosphate (TBP) and other alkyl phosphates represent a class of persistent organophosphorus compounds of widespread use. Biodegradation of the phosphotriesters is postulated to occur through sequential hydrolytic cleavages via the phosphodiester and monoester intermediates to alcohol and inorganic phosphate (P_i). Immobilized cells of aCitrobacter sp. liberated P_i upon challenge with TBP but the reaction was short-lived. In vitro studies with purified phosphomonoesterase (phosphatase) used³¹P nuclear magnetic resonance to demonstrate P_i transfer onto ethanol (phosphotransferase activity). This suggested that in vivo the onset of a futile phosphohydrolytic and transphosphorylation cycle would limit the extent of phosphate production. A mutant deficient in the transphosphorylating phosphomonoesterase showed an extended release of P_i under challenge with TBP that was not subject to the complete and premature reaction termination that precluded application of the parent strain to possible industrial processes for alkyl phosphate biodegradation.     

Trapped inorganic phosphate dimer

Single crystal X-ray crystallographic signature of the pentafluorophenyl substituted tripodal urea-based receptor shows formation of a pseudo dimeric cage which also encapsulates a phosphate dimer via numerous hydrogen bonding and anion[dot dot dot]pi interactions.     

A rapid method for the determination of ammonia (combined) and phosphate in the system of diammonium phosphate and dipotassium phosphate

In systems containing (NH₄)₂HPO₄ and K₂HPO₄, it is possible to determine ammonium and phosphate ions by titrating 2 aliquots using methyl orange as the only indicator. Potassium can be calculated by difference. About 20 min are required for a single analysis.     

Conformational studies on L-serine phosphate and hydrated L-serine phosphate using ab initio SCF calculations

Ab initio MO -LCAO -SCF calculations using an STO -3G basis set were performed to find the most stable conformations of L -serine phosphate and hydrated L -serine phosphate. The most favorable conformation of L -serine phosphate is found to be one where the bond sequence O? C? C? C is trans and P? O? C? C gauche, and a very short hydrogen bond is formed between an oxygen atom of the phosphate group and a hydrogen atom of the ammonium group. For hydrated L -serine phosphate, a bridge-type hydration in which a water molecule links a phosphate oxygen and an ammonium hydrogen displays particularly low energy. In the four-hydrated L -serine phosphate anion, the most favorable conformation is such a bridged one having a rather extended configuration with regard to the bond sequences O? C? C? C and P? O? C? C.