Hu Mancheng

Thermodynamic parameters of the interaction of CsCl with monosaccharide (d-glucose, d-galactose, d-xylose, and d-arabinose) in water at

Abstract A non-liquid-junction electrochemical cell composed of a potassium ion selective electrode(K-ISE) against a chloride ion selective electrode (Cl-ISE) as a reference electrode was employed to study the thermodynamic parameters of weak interactions between aqueous cesium chloride and the monosaccharides ( d -glucose, d -galactose, d -xylose, and d -arabinose) at T=298.15 K . Activity coefficients for this system obtained from electromotive force measurements indicate that they have a close relationship with the stereostructure of the saccharide. The Gibbs free energy pair interaction parameters and salting constants were also evaluated; these can characterize the interaction between the saccharides and CsCl in water. The results were interpreted on the basis of a model of structural and electrostatic interaction and the hydration effect of the hydroxyl ion of these saccharides.

Studies on synthesis, characterization and thermochemistry of Mg2[B2O4(OH)2].H2O

A new magnesium borate Mg2[B2O4(OH)2]·H2O has been synthesized by the method of phase transformation of double salt at hydrothermal condition and characterized by XRD, IR, TG and DSC. The enthalpy of solution of Mg2[B2O4(OH)2]·H2O in 0.9764 mol L−1 HCl was determined. With the incorporation of the enthalpies of solution of H3BO3 in HCl (aq), of MgO in (HCl+H3BO3) (aq), and the standard molar enthalpies of formation of MgO(s), H3BO3(s), and H2O(l), the standard molar enthalpy of formation of −(3185.78±1.91) kJ mol−1 of Mg2[B2O4(OH)2]·H2O was obtained.

Crystal structure and characterization of Rb2Ca[B4O5(OH)4]2·8H2O

Abstract Dirubidium calcium tetraborate octahydrate, Rb 2 Ca[B 4 O 5 (OH) 4 ] 2 ·8H 2 O, was prepared by reaction of Rb-borate aqueous solution with CaCl 2 and its structure has been determined by single-crystal X-ray diffraction data. It crystallizes in the orthorhombic system, space group P 2 1 2 1 2 1 with unit cell parameters, a=11.536(2) A , b=12.639(2) A , c=16.690(4) A ; Z =4, V=2433.5(8) A 3 . The structure contains alternate layers of [B 4 O 5 (OH) 4 ] 2− polyanions separated by water molecules and Rb, Ca cations. The isolated [B 4 O 5 (OH) 4 ] 2− is constructed from two BO 3 (OH) tetrahedron groups and two BO 2 (OH) triangular groups joined at common oxygen atoms. The two BO 3 (OH) tetrahedron groups are further linked by means of an oxygen bridge across the ring. The Ca 2+ ion displays seven coordination, while the two non-equivalent Rb + ions display nine and seven coordination, respectively. Infrared and Raman (4000–400 cm −1 ) spectra of Rb 2 Ca[B 4 O 5 (OH) 4 ] 2 ·8H 2 O were recorded at room temperature and analyzed. Fundamental vibrational modes were identified and band assignments were made. The dehydration of this hydrated mixed borate occurs in one step and leads to an amorphous phase which undergoes a crystallization.

FT-IR and Raman spectroscopic analysis of hydrated cesium borates and their saturated aqueous solution

Hydrated cesium borates have been synthesized by the reaction of Cs(2)CO(3) with H(3)BO(3) aqueous solution. After reaction equilibria were reached, liquid and solid phases were separated and the FT-IR difference and Raman spectra of each phase were recorded, respectively. The assignments of the recorded FT-IR absorption frequencies and Raman shift are given. The main polyborate anions and their interaction in borate aqueous solution have been proposed. The relations between the existing forms of polyborate anions and the crystallizing solid phases, Cs(2)B(4)O(7).5H(2)O and CsB(5)O(8).4H(2)O, have been gained.

Equilibrium phase behavior of ethylene glycol/glycerin+RbNO3/CsNO3+H2O at 288.15 and 298.15 K

The solubilities, densities and refractive indices for the four ternary systems ethylene glycol/glycerin+RbNO3/CsNO3+H2O were measured with mass fractions of ethylene glycol or glycerin in a range of 0 to 1.0 at 288.15 and 298.15 K. In all the cases, the presence of either ethylene glycol or glycerin significantly reduces the solubilities of the rubidium nitrate and cesium nitrate in aqueous solution, but the refractive indices increase with the increase of mass fraction of either ethylene glycol or glycerin. The density, refractive index and solubility of the saturated ternary systems were correlated with each other via polynomial equations. In addition, the refractive indices and densities of unsaturated solutions were also determined for the four ternary systems with different salt concentrations, which were correlated with the salt concentration and proportion of ethylene glycol or glycerin in the solution.