摘要:

AbstractThe solubilities of benzene and diphenyl in mixed solvents oft‐butyl alcohol (TBA) and water with different salts have been determined atT= 298.15, 303.15, 308.15 and 313.15 K. The molar fraction of TBA [x(TBA)] in mixed solvent is 0.045, and the molality of the salts (m2) in mixed solvents are 0.000, 0.250, 0.500, 0.750 and 1.000 mol/kg, respectively. The standard Gibbs energies of solution of benzene and diphenyl in the mixed solvents have also been calculated based on the solubility data. The effects of different salts on the hydrophobic interaction (HI) for benzene‐benzene pair in the systems were discus

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200102

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractThe nano‐sized particles of TiO2were prepared by thermal decomposition of titanium(IV) tetrabutanoxide complex with stearic acid at 450 °C in the air. It was observed that the amount of stearic acid, used initially for the complex synthesis in 2‐propano) at 25 °C, had great influence on the physical properties of the prepared TiO2including crystal structure, the particle size, surface area and the adsorption capacity for organic substrate of a textile dye X3B in water, and thereafter the photocatalytic activity for the dye oxidation. Some samples displayed lower adsorption capacity for the organic substrate in water than a TiO2of Degussa p25, but higher photocatalytic activity for the organic oxidation. Possible reason for the observed difference was discussed in the

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200103

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractThe enthalpy change of reaction of zinc chloride withL‐α‐histidine in the temperature range of 25‐50 °C has been determined by a microcalorimeter. On the basis of experimental and calculated results, three thermodynamics parameters (the activation enthalpy, the activation entropy, the activation free energy), the rate constant and three kinetic parameters (the activation energy, the pre‐exponential constant and the reaction order) of the reaction, and the standard enthalpy of formation of Zn(His)2+(aq.) are obtained. The results showed that the title reaction easily took place at the studied te

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200104

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractThe Li4+xAlxSi1‐xO4‐yAl2O3(x= 0 to 0.5, y =0 to 0.5) ion conductors were prepared by the Sol‐Gel method and examined in detail. The powder and sintered samples were characterized by TG‐DTA, XRD, SEM, and AC impedance techniques. The experimental results show that the conductivity and sinterability increase with the amount of excess Al2O3in the silicate. The particle size of the powder samples is about 0.13 μm. The maximum conductivity at 18 °C. is 3.057 × 10−5s/cm for Li4.4Al0.4Si0.6

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200105

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractA novel organic‐inorganic hybrid compound {[Cu(2, 2′‐bpy)2]2Mo8O26} has been hydrothermally synthesized and structurally characterized by single‐crystal X‐ray diffraction. The compound crystallizes in the orthorhombic space group,Pna21witha= 2.4164(5),b= 1.8281(4),c= 1.1877(2) nm,V= 5.247(2) nm3, Z = 4, and finalR1, =0.0331,wR2, = 0.0727. The structure consists of discrete { [ Cu (2, 2′‐bpy)2]2Mo8O26} dusters, constructed from a β‐octamolybdate subunit [Mo8O26]4‐covalently bonded to two [Cu(2, 2′‐bpy)2]2+coordination complex cationsviabridging oxo groups. In addition, the spectroscopic properties and thermal behavior of this compound have been investigated by spectroscopic techniques (UV‐vis, IR, Raman and EPR

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200106

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractA penta‐coordinated Cu(II) complex with 1,4‐diazacydoheptane(DACH), [Cu(DACH)2(H2O)]Cl2(1), has been synthesized and characterized by X‐ray diffraction, IR spectra, elemental analyses, thermal analyses, UV‐Vis and ESR techniques. Complex 1 crystallizes in orthorhombic crystal system,Pbcnspace group witha= 1.6075(4),b =1.0539(3),c= 0.9195(3) nm,V=l.5578(7) nm3,Mr= 352.79,Z= 4,Dc=1.487 g/cm3, finalR =0.0451 and wR= 0.1294. The structure of 1 indicates that the central Cu(II) atom is penta‐coordinated by four nitrogen atoms of two DACH moieties at the equatorial positions and a water molecule at the axis position. The coordination geometry of Cu(II) could be considered as an approximately ideal square‐pyramidal environment. Both DACH rings arrange incis‐form and are predominantly in the boat‐boat conformation (80%) with some disorder to the chair‐chair conformation (20%). The Cl−anions are hydrogen bonded with the nitrogen donors of the DACH rings and the oxygen donor of the coordinated H2O molecule to form a one‐dimensional zigzag linear structure. The solution behaviors of 1 are also discussed in detail by Uv

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200107

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractA new layered divalent metal monohydrogenphosphate [Co(H2O) (HPO4)] · H2O (1) was hydrothermally synthesized from the reaction of CoCl2·6H2O with H3PO4in the presence ofcis‐Pt(NH3)2Cl2and ethylenediamine. The structure features extensive intra‐ and inter‐layer hydrogen bonding among the hydrogenphosphate anion, the coordinated water and the crystallization water. X‐ray crystallographic parameters for 1 are orthorhombicPnma(#62),a= 1.7528(2),b=0.56158(7),c= 0.47867(6) nm,V= 0.47116(9)

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200108

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractThe synthesis and analytical properties of 4,4′‐bis(antipyrinyl‐4‐diazoamino) biphenyl (BAPDAB) were described for the first time. A catalytic kinetic method for the determination of silver was proposed. In the presence of Triton X‐100 as a solubilizing agent and 2,2′‐dipyridyl as an activator, silver has a very strong catalytic effect on oxidative decoloration of BAPDAB by persulfate in acetic add medium. The reaction was followed spectrophotometrically by measuring the decrease of absorbance of BAPDAB at 478 nm and 50 °C. The calibration graphs are of good linearity in the range of 8.0 × 10−10–1.0 × 10−6mol/L by a fixed time method. The limit of detection is down to 5.0 × 10−10mol/L. The catalytic reaction is pseudo‐first‐order with respect to silver, which in real samples was determi

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200109

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractAn improved procedure for extraction and purification of boron from natural samples is presented. The separation and purification of boron was carried out using a boron‐specific resin, Amberlite IRA743, and a mixed ion exchange resin, Dowex 50W × 8 and Ion Exchanger II resin. Using the mixed ion exchange resin which adsorbs all cations and anions except boron, the HCl and other cations and anions left in eluant from the Amberlite IRA 743 were removed effectively. In this case, boron loss can be avoided because the boron‐bearing solution does not have to be evaporated to reach dryness to dislodge HCl. The boron recovery ranged from 97.6% to 102% in this study. The isotopic fractionation of boron can be negligible within the precision of the isotopic measurement. The results show that boron separation for the isotopic measurement by using both Amberlite IRA 743 resin and the mixed resin is more effective than that using Amberlite IRA 743 resin alone. The boron in samples of brine, seawater, rock, coral and foraminifer were separated by this procedure. Boron isotopic compositions of these samples were measured by thermal ionization mass spectrometry in this s

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200110

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractIt is found that in the presence of sulfuric add carbohydrates condense with urea to afford the condensation products, which emit fluorescence. Under optimum conditions, the fluorescence intensities of system are proportional to the concentrations of carbohydrates. Based on this linear relationship, quantitative determination of kinds of carbohydrates has been made. Among all the carbohydrates tested, the sensitivity of α‐rhamnose is the highest and its limits of detection reaches 3.5 × 10−8mol/L. So α‐rhamnose can be selectively determined in the presence of other carbohydrates. A interaction mechanism is also d

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200111

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY