摘要:

AbstractSheet‐like calcite array and stable vaterite were synthesized by bio‐mimetic supported liquid membrane system under different reaction conditions. Both of the FTIR spectra of products showed narrower peak at 1418 cm−1than that of bulk CaCO3, and that of vaterite has a split in this

ISSN:1001-604X    

DOI:10.1002/cjoc.20040221002

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

年代:2004

数据来源: WILEY

摘要:

AbstractAmylose tris(3,5‐dimethylphenylcamate) (ADMPC) coated on a kind of small particle silica gel was prepared. On this ADMPC chiral stationary phase (CSP), the direct enantiomeric separation of six novel chiral transition metal tetrahedral clusters has firstly been achieved usingn‐hexane as the mobile phase containing various alcohols as modifiers. The effect of mobile phase modifiers and the structural variation of the solutes on their retention factors (k) and resolutions (Rs) were investigated. The result suggests that not only the structure and concentration of alcohol in mobile phase, but also the structural differences in racemates can have a pronounced effect on enantiomeric separation. ADMPC‐CSP is a suitable CSP for the optical resolution of chiral tetrahedral cluster by

ISSN:1001-604X    

DOI:10.1002/cjoc.20040221003

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

年代:2004

数据来源: WILEY

摘要:

AbstractUnder linear temperature increase condition the thermal behavior and kinetic parameters of the exothermic fmt‐stage decomposition reaction of the title compound were studied by means of DSC and TG‐DTG. The empirical kinetic model function in differential form, apparent activation energy and pre‐exponential constant of this reaction are α0.122(1−α)0.528, 216.4 kJ·mol−1and 1020.51 s−1respectively. The critical temperature of thermal explosion of the compound is 222.25 °C. The values of Δ≠S, Δ≠H, and Δ≠Gand of this reaction are 108.3 J·mol−1K−1, 205.1 kJ·mol−1

ISSN:1001-604X    

DOI:10.1002/cjoc.20040221004

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe thermal behavior and kinetic parameters of the decomposition reaction of triethylene glycol dinitrate (TEGDN) in a temperature‐programmed mode at different pressures (0.1, 2, 4 and 6 MPa) have been investigated by means of DSC and TG‐DTG. The results show that the properties of the thermal decomposition of TEGDN are affected by the change of pressure, and the kinetic model function, the apparent activation energyEa. and pre‐exponential factorAof this reaction are 2(1−α)[−ln(1−α)]1/2, 106.54 kJ·mol−1and 109.17s−1at 0.1 MPa, and 120.82 kJ·mol−1and 1010.56s−1at 2 MPa, respectively. The critical temperature of thermal explosion of TEGDN obtained by the valuesTeoandTpoof the onset temperatureTeand the peak temperatureTpwhen the heating rate tends to zero are 191.05, 209.86 °C at 0.1 MPa, 207.59 and 221.65

ISSN:1001-604X    

DOI:10.1002/cjoc.20040221005

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe kinetic parameters of the exothermic decomposition reaction of the title compound in a temperature‐programmed mode have been studied by means of DSC. The empirical kinetic model function in differential form, apparent activation energy (Ea) and pre‐exponential factor (A) of this reaction are (1−α)0.222, 225.8 kJ·mol−1and 1020.21s−1, respectively. The critical temperature of thermal explosion of the compound

ISSN:1001-604X    

DOI:10.1002/cjoc.20040221006

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe thermal behaviors of the complexes of CU(DMTZB)4X2(DMTZB=3,3′‐dimethyl‐1‐(1H‐1,2,4‐triazol‐1‐yl)‐2‐butanone, X=NO3or ClO4) and CU(DMTZB)2X2(X=Br or Cl) in a nitrogen atmosphere were studied under the non‐isothermal conditions by simultaneous TG‐DTG‐DSC. EDS and elemental analysis techniques. The results showed that their decomposition proceeded in three different ways mainly depending on the anions in the molecules. The heat effect associated with the decomposition step of DMTZB molecules was also different. The decomposition mechanisms and the kinetic parameters of DMTZB were determined and calculated by jointly using four methods, which showed that its pyrolysis was controlled by D3 mechanism but with different activation energies and pre‐exponential fact

ISSN:1001-604X    

DOI:10.1002/cjoc.20040221007

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe thermal behaviors of clusters [Ag3WS3Br](PPh3)3and [Cu3WS3Br](PPh3)3(PPh3=triphenyl phosphine) in a nitrogen atmosphere were studied under the non‐isothermal conditions by simultaneous TG‐DTG‐DSC and EDS techniques. The results showed that the evolution of PPh3generally proceeded before the release of the other moiety in one or two step‐mode. The mechanisms, the kinetic and the thermodynamic parameters for decomposition of PPh3of both clusters were determined and calculated by jointly using several methods, which showed that its evolution was controlled by Avrami‐Erofeev equation. The results also showed that there was no new stable phase composed of W‐Ag(Cu)‐S‐Br after release of organic moiety PPh3and that CVD method was not applicable to their fur

ISSN:1001-604X    

DOI:10.1002/cjoc.20040221008

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe crystal growth process of Zn(Met)(AcO)2·H2O from the mixed solution of water and acetone has been investigated using a Calvet microcalorimeter. The heat produced and the rate of heat production during the crystal growth process at 298.15, 301.15, 304.15, 307.15 and 310.15 K have been measured. On the basis of experimental and calculated results, the thermodynamics parameters (the apparent activation enthalpy, the activation entropy, and the activation free energy), the rate constant and the kinetic parameters (the activation energy, the pre‐exponential factor) during the crystal growth process have been obtained. The results show that the crystal growth proceeds in accordance with the Burton‐Cabrera‐Frank dislocation

ISSN:1001-604X    

DOI:10.1002/cjoc.20040221009

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe complex of Zn(AcO)2·2H2O and threonine was prepared in the mixture solvent of water‐acetone, the composition of which was identified as Zn(Thr)(AcO)2·2H2O by chemical and elemental analyses. The complex was investigated by XRD, JR, TG‐DTG and DSC methods. The result of TG‐DTG shows that the thermal decomposition processes of the complex can be divided into three stages, which were dehydration (I), partial decomposition (II) and complete decomposition into ZnO (III). Dehydration enthalpy was 126.89 kj·mol−1, decomposition enthalpy of the stage (II) was 79.50 kJ·mol−1. The study of non‐isothermal kinetics shows that the mechanism of the dehydration stage was Maple Power ofn=3/2, the apparent activation energyEwas 145.32 kJ·mol−1and the pre‐exponential factor A was 1.4125×1017s−1, and that of ligand‐losting process was nucleation and growth mechanism (Avrami‐Erofeev equationn=1/2), itsEwas 189.33 kJ·mol−1, and A was 3.4674×s−1. The empirical kinetics model equations of the inv

ISSN:1001-604X    

DOI:10.1002/cjoc.20040221010

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

年代:2004

数据来源: WILEY

摘要:

AbstractThe title ternary complex Nd[(C5H8NS2)3(C12H8N2)] has been synthesized in absolute ethanol by the reaction of NdCl3·3.74H2O with ammonium pyrrolidmyldifhiocaboxylate (APDC) and 1,10‐phenanthroline (phen·H2O) at air atmosphere without any cautions against moisture. The bonding characteristics of the complex were characterized by IR, showing that Nd3+is bonded with sulfur atom in the APDC and coordinated with nitrogen atom in the phen. TG‐DTG investigation indicates that the title complex was decomposed into Nd2S3and deposited carbon in one step where Nd2S3predominated in the final products. The enthalpy change of formation of the reaction on the title complex in liquid‐phase has been determined by a microcalorimeter. Thermodynamic parameters (the activation enthalpy, the activation entropy and the activation free energy) and kinetics parameters (the rate constant, the apparent activation energy, the pre‐exponential constant and the reaction order) of the title reaction have been calculated. The enthalpy change of the soLid‐phase reaction has been obtained by a thermochem

ISSN:1001-604X    

DOI:10.1002/cjoc.20040221011

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

年代:2004

数据来源: WILEY