3-D phase diagram of HPC/H2O/H3PO4 tertiary system

A 3-D phase diagram of the HPC/H₂O/H₃PO₄ tertiary system against various temperatures was established. Four distinct phases—the completely separated phase (S), the cloudy suspension phase (CS), the liquid crystalline miscible phase (LC), and the isotropically miscible phase (I)—were identified. The S phase shrank as the temperature increased, revealing that the HPC solubility increased with temperature, regardless of the LCST (lower critical solution temperature) characteristic. The addition of H₃PO₄ suppressed the formation of LC phase. However, as the temperature was raised sharply from 50 to 70?°C, the LC phase could only be maintained at high H₃PO₄ concentration region; it was a triangular shape, and the top apex of the triangle was the temperature-invariant L* point (HPC/H₂O/H₃PO₄ 38/9/53?wt%). The CS phase expanded considerably into the H₂O-rich but H₃PO₄-poor region when the temperature continued to increase over 48?°C. The LCST points of the CS phase that contained 0 and 15?wt% of H₃PO₄ were 34 and 38?°C, respectively. These CS results demonstrate that H₃PO₄ suppresses the occurrence of LCST behavior. Additionally, the binodal curve exhibits a weak or even zero dependence of binodal temperature on the HPC concentration at HPC concentrations of less than 30?wt% in a pure water system. A hypothesis concerning the sequential desorption of water molecules was proposed to explain such behavior.     

Liquid crystalline phase in xanthan gum (XG)/H2O/H3PO3 and XG/H2O/H3PO4 tertiary systems: a thermal and rheological study

This study investigates the difference in phase transition and rheological behavior between xanthan gum (XG)/H₂O/H₃PO₃ (XWP₃) and XG/H₂O/H₃PO₄ (XWP₄) tertiary systems using polarized optical microscopy, Fourier transform infrared spectroscopy, light transmission detection, and rheometry. The results show that the LC (liquid crystal) phase formation in the XWP₄ system was more strongly suppressed than that in the XWP₃ system because the former exhibited stronger interactions between acid and XG molecules. With respect to the transition from LC to I (isotropic) phase at high temperature, the transition time of the XWP₄ system was found to be much shorter than that of the XWP₃ system. The transition time, also called the relaxation time, was measured by observing the annealing time and fitted using the VFT expression. The activation energies E for this transition in XWP₄ and XWP₃ systems are 3.0 and 4.7 kJ/mole, respectively, indicating that the XWP₃ system exhibits stronger intermolecular attraction and is more sensitive to variation in temperature. In the rheological tests, as the temperature of the XWP₄ system increased from 25 to 95 °C, the viscosity in the transitional region declined consistently, while in the XWP₃ system, the decline proceeded through three stages owing to the shifting tautomers of the H₃PO₃. In the LC region, the viscosity normally fell as the shear rate or temperature increased but increased with the heating rate or XG concentration. Most interestingly, all of the results herein demonstrated that the viscosity of the XG solution in the LC region followed a power law with an index of roughly 0.08, which was found to be independent of the type of acid, concentration of acid, and XG concentration.     

Phase formation and transition in a xanthan gum/H2O/H3PO4 tertiary system

Phase formation and transition in a xanthan gum (XG)/H₂O/H₃PO₄ tertiary system were characterized by polarized optical microscopy, light transmission detection and rheological methods. Three distinct phases and a transition region—the completely separated (S) phase, the liquid crystalline (LC) miscible phase, the isotropically (I) miscible phase and the S plus LC region—were identified. The presence of H₃PO₄ in the XG/H₂O system inhibited the evolution of both the S and LC phases. The S and LC phases contained less than 73 and 62 wt% of H₃PO₄, respectively. As the temperature increased over 65 °C, the LC phase in the H₃PO₄-rich and H₂O-poor region seriously shrunk owing to the breakup of hydrogen bonds among the XG helical structure. At the same XG loading, the viscosity of the XG solutions in LC phase was found to be much higher than that in I phase. It indicated the existence of numerous XG intermolecular interactions in the LC phase that suppress the movement of liquid. A study of the kinetics demonstrated that the shrinkage relaxation time (τ) depended strongly on temperature and was fitted by the Volgel-Fulcher-Tammann (VFT) expression. The potential energy barrier of this liquid was quite low at approximately 3.0 kJ mol^?1, falling in the range of hydrogen-bond disassociation. The light absorbance test in heating mode revealed a biphasic transitional region between the LC phase and I phase. The contour of this region depended on the heating rate, and this fact was explained again by the relaxation behavior of XG helices at temperatures higher than 65 °C.     

Muon spin relaxation study of Zr(H2PO4)(PO4).2H2O

Muon spin relaxation has been used to study the muon dynamics in the layered zirconium phosphate Zr(H(2)PO(4))(PO(4)).2H(2)O as a function of temperature. Radiofrequency decoupling was used to establish the origin of the local dipolar field as coupling with (1)H spins. Muons were trapped at two sites, one identified as HMuO and the other consistent with PO-Mu on the basis of their zero-field second moments. Although a small decrease in the local nuclear dipolar field was seen with temperature, the muons remained essentially static over the temperature range 20-300 K.     

NH4VO3在NH4H2PO4-H2O和(NH4)3PO4-H2O体系中的溶解度

采用等温溶解法测定了偏钒酸铵(NH₄VO₃)在NH₄H₂PO₄-H₂O和(NH₄)₃PO₄-H₂O体系中T = 298.15-328.15 K时的溶解度以及溶液的密度和pH值。结果表明, NH₄VO₃的溶解度随着(NH₄)₃PO₄或NH₄H₂PO₄溶液浓度的增大,先降低后升高,这是由于同离子效应、化学反应平衡及离子活度的共同作用。比较T = 298.15K时, NH₄VO₃分别在NH₄H₂PO₄-H₂O、(NH₄)₂HPO₄-H₂O和(NH₄)₃PO₄-H₂O体系中溶解度,发现在相同的磷酸盐浓度下, NH₄VO₃的溶解度在NH₄H₂PO₄-H₂O体系中最大,在(NH₄)₃PO₄-H₂O体系中居中,在(NH₄)₂HPO₄-H₂O体系中最小。进一步地,在T = 298.15 K和磷酸盐浓度C = 0.5 mol·kg^-1时,结合pH值和反应溶度积常数K_SP等计算三个体系中的平均离子活度系数(γ_±),发现γ_±值在(NH₄)₂HPO₄-H₂O体系中最大,在(NH₄)₃PO₄-H₂O体系中居中,在NH₄H₂PO₄-H₂O体系中最小,与溶解度规律一致。     

Die IR-Spektren von NH4UO2AsO4·3H2O und NH4UO2PO4·3H2O

The infrared spectra of the title compounds, as well as that of the structurally related mineral meta-autunite, [Ca(UO₂)₂(PO₄)₂·n H₂O], are reported and discussed using the available crystallographic data. The results can be considered as representative for the full group of the so-called torbernite-minerals.     

Two new open framework cobalt phosphates: NaCo3(OH)(PO4)2.1/4H2O and Na(NH4)Co2(PO4)2.H2O

Two new cobalt phosphates, NaCo₃(OH)(PO₄)₂.1/4H₂O (1) and Na(NH₄)Co₂(PO₄)₂.H₂O (2) have been synthesized hydrothermally and characterized by single crystal X-ray diffraction methods, vibrational (IR and Raman) spectroscopy, thermogravimetric analysis and magnetic measurements. The structure of 1 is a new framework type while 2 is an example of a chiral cobalt phosphate. Both phases contain channels in which the Na⁺, NH₄⁺ cations and H₂O molecules are located.     

A hydrothermal investigation of the 1/2V2O5-H2C2O4/H3PO4/NH4OH system: synthesis and structures of (NH4)VOPO(4).1.5H2O, (NH4)0.5VOPO(4).1.5H2O, (NH4)2[VO(H2O)3]2[VO(H2O)][VO(PO4)2](2).3H2O, and (NH4)2[VO(HPO4)]2(C2O4).5H2O

The 1/2V2O5-H2C2O4/H3PO4/NH4OH system was investigated using hydrothermal techniques. Four new phases, (NH4)VOPO(4).1.5H2O (1), (NH4)0.5VOPO(4).1.5H2O (2), (NH4)2[VO(H2O)3]2[VO(H2O)][VO(PO4)2]2.3H2O (3), and (NH4)2[VO(HPO4)]2(C2O4).H2O (4), have been prepared and structurally characterized. Compounds 1 and 2 have layered structures closely related to VOPO(4).2H2O and A0.5VOPO4.yH2O (A = mono- or divalent metals), whereas 3 has a 3D open-framework structure. Compound 4 has a layered structure and contains both oxalate and phosphate anions coordinated to vanadium cations. Crystal data: (NH4)VOPO(4).1.5H2O, tetragonal (I), space group I4/mmm (No. 139), a = 6.3160(5) A, c = 13.540(2) A, Z = 4; (NH4)0.5VOPO(4).1.5H2O, monoclinic, space group P2(1)/m (No. 11), a = 6.9669(6) A, b = 17.663(2) A, c = 8.9304(8) A, beta = 105.347(1) degrees, Z = 8; (NH4)2[VO(H2O)3]2[VO(H2O)][VO(PO4)2]2.3H2O, triclinic, space group P1 (No. 2), a = 10.2523(9) A, b = 12.263(1) A, c = 12.362(1) A, alpha = 69.041(2) degrees, beta = 65.653(2) degrees, gamma = 87.789(2) degrees, Z = 2; (NH4)2[VO(HPO4)]2(C2O4).5H2O, monoclinic (C), space group C2/m (No. 12), a = 17.735(2) A, b = 6.4180(6) A, c = 22.839(2) A, beta = 102.017(2) degrees, Z = 6.     

新型杂多化合物[(CH3CH2)4N]4H3O· {Na[(HMo2O5)3(HPO4)(H2PO4)3]2}·(H2PO4)2·10H2O的水热合成与晶体结构

杂多化合物在催化、医药、材料及光化学等方面具有广泛的应用前景 [1～ 4 ] ,其中钼磷多金属氧酸盐具有优异的氧化催化性能 [5,6 ] .近年来合成的新奇结构的钼磷多金属氧酸盐中已测定结构的有含帽[7,8] 和非帽[9～ 12 ] 系列 .本文利用水热法合成了未见文献报道的结构新颖的夹心型磷钼多金属氧酸盐[( CH3CH2 ) 4N]4 H3O{Na[( HMo2 O5) 3( HPO4 ) ( H2 PO4 ) 3]2 }· ( H2 PO4 ) 2 · 1 0 H2 O,并测定了其晶体结构 .1　实验与晶体结构分析1 .1　仪器与试剂　元素 Na用美国原子吸收分光光度计测定 ;C,H和 N用 Perkin- Elmer 2 4 0…     

Thermal study of decomposition of Cu1/2Mg1/2(H2PO4)2.0.5 H2O

c-CuMgP₄O₁₂ is an industrial product used for various practical purposes. Its preparaton from Cu_1/2Mg_1/2(H₂PO₄)₂.0.5H₂O by calcination was studied by means of thermal analysis and extraction methods under different experimental conditions, in particular at different partial pressures of water vapour with the sample in contact. The intermediates and end-products were identified and the optimal conditions for the formation ofc-CuMgP₄O₁₂ are given.

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Zusammenfassung CuMgP₄O₁₂ ist ein Industrieprodukt, das zu vielen praktischen Zwecken verwendet wird. Seine Herstellung aus Cu_0.5Mg_0.5(H₂PO₄)₂.0.5H₂O durch Kalzinieren wurde mittels Thermoanalyse und Extraktionsverfahren unter verschiedenen experimentellen Bedingungen untersucht, insbesondere bezogen auf den die Probe umgebenden partiellen Wasserdampfdruck. Zwischenprodukte und Endprodukte wurden identifiziert und die optimalen Bedingungen für die Bildung von c-CuMgP₄O₁₂ gegeben.

     

Vibrational analysis of Ag3(PO2NH)3, Na3(PO2NH)3 x H2O, Na3(PO2NH)3 x 4H2O,

FT IR and FT Raman spectra of Ag3(PO2NH), (Compound 1), Na3(PO2NH)3 x H2O (Compound II), Na3(PO2NH)3 x 4H2O (Compound III), [C(NH2)3]3(PO2NH)3 x H2O (Compound IV) and (NH4)4(PO2NH)4 x 4H2O (Compound V) are recorded and analyzed on the basis of the anions, cations and water molecules present in each of them. The PO2NH- anion ring in compound I is distorted due to the influence of Ag+ cation. Wide variation in the hydrogen bond lengths in compound III is indicated by the splitting of the v2 and v3 modes of vibration of water molecules. The NH4 ion in compound V occupies lower site symmetry and exhibits hindered rotation in the lattice. The correlations between the symmetric and asymmetric stretching vibrations of P-N-P bridge and the P-N-P bond angle have also been discussed.     

Na2Co(H2PO4)4·4H2O

In the title compound, disodium cobalt tetrakis­(dihydrogen­phosphate) tetrahydrate, the Co^II ion lies on an inversion centre and is octahedrally surrounded by two water molecules and four H₂PO₄ groups to give a cobalt complex anion of the form [Co(H₂PO₄)₄(OH₂)]^2?. The three‐dimensional framework results from hydrogen bonding between the anions. The relationship with the structures of Co(H₂PO₄)₂·2H₂O and K₂CoP₄O₁₂·5H₂O is discussed.     

Ce(H2O)(PO4)3/2(H3O)1/2(H2O)1/2, a second entry in the structural chemistry of cerium(IV) phosphates

A cerium(IV) phosphate has been prepared using precipitation methods and its structure has been solved by single crystal X-ray diffraction (R₁ = 0.0292 for 3092 reflections with I>2σ(I) and wR₂ = 0.0540). Ce(H₂O)(PO₄)_3/2(H₃O)_1/2(H₂O)_1/2 crystallises in the monoclinic space group C2/c (a = 15.7058(17) Å, b = 9.6261(9) Å, c = 10.1632(4) Å, ß = 121.623(7)°, and V = 1308.4 (2) Å³). Its structure is based on a negatively charged 3D framework, made of cerium atoms connected by PO₄ tetrahedra. There are two types of PO₄ units; one shares only corners with the cerium coordination polyhedra while the other one shares edges and corners. This structure also includes hydronium cations, to balance the framework charge, and water molecules. One special feature of this 3D framework is the formation of interconnected tunnels which extend along the c axis and contain the hydronium cations and the water molecules. This open framework and the presence of cationic species in the tunnels are in perfect agreement with the previously reported ion exchange properties.     

DMSO/N2H4.H2O/I2/H2O/CH3CN: a new system for selective oxidation of alcohols in hydrated media

A new alternative system for the oxidation of secondary alcohols to ketones with DMSO/N2H4.H2O/I2/H2O/CH3CN in hydrated media has been developed. The system also selectively oxidizes the secondary alcoholic groups to the corresponding ketones in the presence of primary alcoholic groups present within the same molecule in moderate to very good yields at reflux temperature.     

The system YPO4-Mg3(PO4)2-Mg2P2O7

Phase equilibria in the systems YPO₄-Mg₃(PO₄)₂, YPO₄-Mg₂P₂O₇ and YPO₄-Mg₃(PO₄)₂-Mg₂P₂O₇ have been examined by thermal, X-ray and microscopic methods. Their phase diagrams have been provided.

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Zusammenfassung Mittels thermischen, röntgenografischen und mikroskopischen Methoden wurden die Phasengleichgewichte in den Systemen YPO₄-Mg₃(PO₄)₂, YPO₄-Mg₂ P₂O₇ und YPO₄-Mg₃(PO₄)₂-Mg₂P₂O₇ untersucht und deren Phasendiagramme ermittelt.

     

Hydrothermal Synthesis and Crystal Structure of a New Phosphonate： {[Cu（1,10-phen）]2-（H2O3PCH2C6H4C6H4CH2PO3H）2-（HO3PCH2C6H4C6H4CH2PO3H） }n

1 INTRODUCTION Metal organophosphonates have attracted considerable attention for over three decades due to their potential or practical applications, include- ing ion exchanges[1, 2], molecular sensors[3] and optics[4, 5]. Recently, a number of porous m…