摘要:

AbstractA novel sensitive probe for proton based on platinum(II) terpyridyl acetylide complex by monitoring the changes both in luminescence and color is described.

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220102

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe molar heat capacity of the azeotropic mixture composed of water and benzene was measured by an adiabatic calorimeter in the temperature range from 80 to 320 K. The phase transitions took place in the temperature range from 265.409 to 275.165 K and 275.165 to 279.399 K. The phase transition temperatures were determined to be 272.945 and 278.339 K, which were corresponding to the solid‐liquid phase transitions of water and benzene, respectively. The thermodynamic functions and the excess thermodynamic functions of the mixture relative to standard temperature 298.15 K were derived from the relationships of the thermodynamic functions and the function of the measured heat capacity with respect to temperatur

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220103

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe acidic strength of ordered mesoporous aluminosilicates of MAS‐2, MAS‐3, MAS‐7 and MAS‐9 and microporous crystals of Y. L, beta, and ZSM‐5 zeolites was systemically investigated by temperature‐programmed desorption of ammonia (NH3‐TPD). Due to the use of preformed zeolite precursors of Y. L, beta and ZSM‐5, the ordered mesoporous aluminosilicates with distinguished acidic strength were obtained. being dependent on the type of preformed zeolite precursors. Therefore, the acidic strength of these mesoporous aluminosilicates could be tailored

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220104

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe phase diagrams of the CH3CH2OH‐Cs2CO3‐H2O system were determined at 10, 30 and 50 C, respectively. It was found that the effect of the temperature on the phase equilibrium was insignificant within the investigated range. The binodal curves were given using a five‐parameter equation and the tie lines were fitted using the Oth‐mer‐Tobias and Bancroft correlations. Correlation coefficients (R) for all equations exceeded 0.99. Samples of the solid phase at 30 °C were analyzed by TGA showing that it consisted of Cs2CO3. 3.5H2O. The refractive index of the systems was also

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220105

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe kinetics of the first order autocatalytic decomposition reaction of nitrocellulose (NC, 13.86% N) was studied by using DSC. The results show that the DSC curve for the initial 508 of conversion degree of NC can be described by the first order autocatalytic equationand that for the latter 50% conversion degree of NC described by the reaction equations.

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220106

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe mechanism of cycloaddition reaction between singlet alkylidene carbene and ethylene has been investigated with second‐order Moller‐Plesset perturbation theory (MP2). By using 6–31G* basis, geometry optimization, vibrational analysis and energetics have been calculated for the involved stationary points on the potential energy surface. The results show that the title reaction has two major competition channels. An energy‐rich intermediate (INT) is firstly formed between alkylidene carbene and ethylene through a barrier‐free exothermic reaction of 63.62 kJ/mol, and the intermediate then isomerizes to a three‐membered ring product (Pl) and a four‐membered ring product (P2) via transition state TS1 and TS2, in which energy barriers are 47.00 and 51.02 kl/mol. respectively. PI is the

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220107

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe phase behavior of the aqueous solution of poly(vinyl methyl ether) (PVME) sensitive to temperature and the modification of the behavior by using poly(acrylic acid) (PAA) have been studied by ultrasonic attenuation measurements and fluorescence probe techniques. It has been observed that PVME solution is transparent at mom temperature and becomes turbid upon heating. The solution turns clear again as smn as the temperature is decreased to room temperature. The heating and cooling process can be repeated for many times. The phase behavior of the solution sensitive to temperature is attributed to the conformational changes of the polymer. PVME may adopt an open coil conformation at mom temperature. With this conformation, the polymer is well miscible with the solvent, water, and thereby the system is a real solution. The polymer may adopt a compact coil conformation when the temperature is higher than a specific value. which is called the LCST (the lower critical solution temperature) of PVME. In this case, the polymer tangles to each other and forms various aggregates, which can scatter incident light and ultrasonic waves greatly. resulting in the phase separation, Introduction of PAA decreases the temperature sensitivity of the phase behavior of the polymer. The nature of the inhibition is attributed to the complexation of PAA with PVME and the strong hydrophilicity of PAA. Results from fluorescence probe studies are in accordance with those from ultrasonic attenuation measurements, indicating again that the ultrasonic attenuation method can be successfully used for the qualitative studies of polymer conformations and complexation between polymers.

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220108

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

年代:2004

数据来源: WILEY

摘要:

AbstractOne‐dimensional V2O5nanowires have been synthesized inside the channels of mesoporous silica SBA‐15 through chemical approach, which involves aminosilylation of silanol groups on the silica surface, anchoring of isopoly acid, H6V10O28. by neutralization of basic amine groups, and thermal decomposition. The formation and physicochemical properties of the nanowires were monitored and studied by TG‐DTA, variable temperaturein situXRD, TEM, N2sorption measurements and UV‐Vis DRS. The results indicate that V2O5nanowires formed within SBA‐15 channels belong to orthorhombic polycrystal domains. The oxygen‐to‐metal charge transfer band of V2O5nanowires shows a blue shift in comparison with bulk V2O5, which clearly exhibits the quantum size effect

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220109

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe first hyperpolarizabilities of a series of novel azulenic‐barbituric acid chromophores have been studied by using 12 excitation wavelengths, ranging from 900 to 1907 nm. The dispersion relation of the first hyperpolarizabilities of chromophors holds the same tendency as the experimental results. In addition. the static first hyperpolarizabilityβ0of molecules was calculated by means of the Sum‐Over‐States (SOS) expression and the two‐level formula respectively. The results show that these molecules possess large static fast hyperpolarizabilities and theβ0value increases as the donor or acceptor strength enhances; the distorted degree of molecules has also an important influence on t

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220110

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe conductivities of polyethylene oxide (PEO)‐based polymer electrolytes (PE) can be improved by the addition of inorganic inert powder. The composite polymer electrolytes (CPE) PEO10LiX (X = ClO−4or N(CF3SO2)2)‐Li2TiO3were prepared by solution casting with inorganic solid electrolyte Li2liO3powder as a filler. Results showed that the conductivities of PEO10LiClO4‐‐3wt% Li2TiO3and PEO10LiN(CF3SO2)2‐10wt% Li2TiO3at 30 °C were 8.6×10−‐6and 5.6×10−‐5S·cm−l, respectively. The conductivities of CPE increased with the decrease of filler's particle size. The ionic conduction mechanism analysis showed that there may be thee conduction routes in the CPE.i.e., PEO bulk, polymer‐filler i

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220111

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

年代:2004

数据来源: WILEY