ISSN:0005-9021    

DOI:10.1002/bbpc.19830870102

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe solubility of water in 2‐butanol, iso‐butanol, 2‐pentanol, n‐hexanol, n‐heptanol and n‐octanol as a function of water activity was determined at 25°C. Applying the Gibbs‐Duhem relationship, the activities of alcohols and the excess free energies of mixing were evaluated in the binary alcohol

ISSN:0005-9021    

DOI:10.1002/bbpc.19830870104

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

年代:1983

数据来源: WILEY

摘要:

AbstractStatic permittivities (ϵ), excess enthalpies (HE), and excess volumes (VE) of Cyclohexane or Benzene + 1,2‐Dibromoethane, and the densities and refractive indices of the pure components, at 288.15, 298.15, 308.15 and 308.15 K, were measured. The dielectric measurements allowed the study of the conformational equilibrium and the calculation of the equilibrium constant and the conformational enthalpy. We have found thatHEis practically independent ofTin the range studied by us, and an explanation of this result is proposed. The influence of the temperature onVEis small and negative.HEandVEdata were correlated in terms of Flory‐Patterson's th

ISSN:0005-9021    

DOI:10.1002/bbpc.19830870105

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe isotherms and the heats of selective adsorption of n‐fatty acids (C4, C12, C18) at the alumina/n‐heptane interface have been determined at 313 K. All adsorption isotherms show stepwise trend of the L‐4 type isotherm according to Gile's classification. This behaviour has been interpreted assuming progressive rearrangement in the adsorbed layer with partial formation of dimers of n‐fatty acid molecules in correspondence of high surface coverage. – As the monocarboxylic acid orientation is concerned limiting adsorption from n‐heptane is consistent with the hypothesis of the surface structure made up of symmetric bidentate carboxylate ions, with the molecular symmetry axis rotating away from the perpendicular, orientation. – Studying the effects of the sample outgassing temperature upon the differential heats of adsorption, one may assume that:i)AtT≤ 573 K the differential heats are typical of hydrogen bonding between fatty acids' carboxylic group and isolated surface hydroxyls groups.ii)At higher outgassing temperatures the heats of selective adsorption are representative of dissociative chemisorption on c.u.s. sites.In correspondence of higher surface coverages aspecific Van der Waals interactions become prevalent. – The differential heats of adsorption for all η‐ and α‐alumina samples decrease as the chain length increases. – α‐Al2O3differential heats are smaller

ISSN:0005-9021    

DOI:10.1002/bbpc.19830870106

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe design of absorption processes requires the knowledge of gas solubility data. Because experimental data are often not available, an estimation method must be used. Various methods for the prediction of gas solubilities have been published in the literature. It is shown that none of the described methods provides satisfactory prediction results. Therefore a new method – the modified UNIFAC method – is proposed. This modification of the UNIFAC method takes into account free volume effects. The method has been used successfully for the estimation of carbon dioxide, methane, oxygen and ethylene solubilities in aliphatic hydrocarbons and alcohols at 1

ISSN:0005-9021    

DOI:10.1002/bbpc.19830870107

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

年代:1983

数据来源: WILEY

摘要:

AbstractBy introducing the concept of tracer transport into the equations of thermodynamics of irreversible processes it is possible to link unequivocally the phenomenological transport coefficients of irreversible thermodynamics to the velocity correlation coefficients of the linear response theory. The equations derived are valid for neutral and/or ionic constituents or species.

ISSN:0005-9021    

DOI:10.1002/bbpc.19830870108

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

年代:1983

数据来源: WILEY

摘要:

AbstractConventional partition function of free internal rotation shows incorrect limit behaviour for low temperatures and small values of reduced moment of inertia. Consequences of transition to the new formula with correct limit behaviour regarding calculations of thermodynamic functions have been studied for CH3NO2, C6H5NH+, C6H5, – C6H5, CIF, HF · HF CIF, CF3H · OH2, CCl3H · OH2· C3H6OH2, (H2)2, and (H2O)2. In the case of association of HF and CIF the thermodynamic characteristics of the overall process have also been recalculated in the terms of the newly suggested approach. It has been shown that application of the new formula can cause substantial changes inH T0andS T0values in the region of not only low but also moderate temperatures. Corrections of values of the thermodynamic characteristics which are required by this improved procedure can be more significant than or comparable with the values of corrections with respect to deviations from behaviour of rigid rotator or harmonic oscillator. As a side product the study points out a number of numerical errors and non‐reproducibilities of the earlier reported values based on the conventio

ISSN:0005-9021    

DOI:10.1002/bbpc.19830870109

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

年代:1983

数据来源: WILEY

摘要:

AbstractIn order to investigate the relationship between the viscosity‐pressure behavior and the structure of the molecule the viscosities η of Diphenyl‐methane, Dicyclohexylmethane, Triphenylmethane, Tricyclohexylmethane as well as those of unhydrogenized and hydrogenized Bixylyltoluene and Terxylyltoluene were measured between 25 and 80°C up to 2 kbar. It is found, that in each case the viscosity‐pressure dependence is strongly enhanced by hydrogenation. – Furthermore thepVT‐data of unhydrogenized and hydrogenized Bixylyltoluene were measured and reproduced by the equation of Tait. The lg η‐isotherms as‐function of density ρ, the lg η‐isochors as function of 1/T, the heat of activationEpand the energy of activationEvare discussed.Epis diminished to higher temperatures and is enhanced with increasing pressure. However the rationEp/Evis approximately equal to 2, independent of temp

ISSN:0005-9021    

DOI:10.1002/bbpc.19830870110

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

年代:1983

数据来源: WILEY

摘要:

AbstractMelting curves and densities have been determined for this system, from which activity coefficients, excess Gibbs energies and excess volumes were evaluated. The results are interpreted similar to the acetic acid + benzene system, with dibutylphosphate (HDBP) to undergo strong dimerization. But with HDBP + benzene, it seems necessary to consider the size differences of the species.

ISSN:0005-9021    

DOI:10.1002/bbpc.19830870111

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

年代:1983

数据来源: WILEY

摘要:

AbstractTrichloroacetic acid petachlorophenyl ester (TCA‐O‐PCP) was found to form a 2:i adduct with benzene. It showed an eight line35Cl NQR spectrum in the range 77 ≦T/K ≦ 312 (decomposition temperature of the adduct). TCA‐O‐PCP was proved to have three crystalline phases. Phase I is stable in the range 77 ≦T/K ≦ 403 (melting point of phase I). It exhibited also an eight line35Cl NQR spectrum. A metastable phase (phase III) was obtained by quenching the liquid TCA‐O‐PCP to 77 K and on heating it was transformed into another metastable phase (phase II) at ca. 310 K. The transition III ⇄ II was enantiotropic and of higher order. AtT/K ≧ ca. 360 a gradual, monotropic transition of II → I was observed. A35Cl NQR spectrum having poor signal to noise ratio was found for phase III. A pronounced rise of the NQR frequency due to steric effect was observed for phase I of TCA‐O‐PCP. Remarkable differences in the characteristics of the NQR spectrum of ‐CCl3group were found between the spectrum of the adduct and that of phase I. Some conformational change of TCA‐O‐PCP molecule accompanied by the adduct formation is thought to be responsible for

ISSN:0005-9021    

DOI:10.1002/bbpc.19830870112

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

年代:1983

数据来源: WILEY