Heats of mixing of cyclohexane with 1-propanol and 2-propanol

1979 ◽  
Vol 44 (10) ◽  
pp. 2869-2881 ◽  
Author(s):  
František Veselý ◽  
Petr Uchytil ◽  
Milan Zábranský ◽  
Jiří Pick
Keyword(s):  
Interaction Parameter ◽  
Binary Systems ◽  
Specific Interaction ◽  
Quantitative Description ◽  
Quantitative Character ◽  
Heats Of Mixing ◽  
Excess Gibbs Energies ◽  
Concentration Dependences ◽  
Temperature Dependences ◽  
Isothermal Calorimeter

The concentration dependences of excess enthalpies of the binary systems cyclohexane-1-propanol and cyclohexane-2-propanol were measured in an isothermal calorimeter at six temperatures in the range of 25-50°C. For the quantitative description of the concentration and temperature dependences of heats of mixing, the Liebermann-Wilhelm model of associated solution was used extended by the assumption of polynomial temperature dependence of the interaction parameter. It follows from the comparison of chemical and physical contribution to the excess enthalpy that heats of mixing in the system with 1-propanol are given mostly by a specific interaction of hydrogen bond. The excess Gibbs energies were estimated using an interaction parameter calculated from heats of mixing. The values obtained are systematically higher and have rather semi-quantitative character.

Concentration and temperature dependence of heats of mixing of 1-butanol, 2-butanol, and 2-methyl-2-propanol with cyclohexane

1983 ◽  
Vol 48 (12) ◽  
pp. 3482-3494 ◽  
Author(s):  
František Veselý ◽  
Vladimír Dohnal ◽  
Miriam Valentová ◽  
Jiří Pick
Keyword(s):  
Entire Range ◽  
Experimental Error ◽  
Binary Systems ◽  
Enthalpy Of Mixing ◽  
Excess Enthalpies ◽  
Heats Of Mixing ◽  
Maximum Value ◽  
Concentration Dependences ◽  
System 2 ◽  
Isothermal Calorimeter

The concentration dependences of excess enthalpies were measured in an isothermal calorimeter within the range of 25-50 °C at six temperatures for the binary systems 1-butanol-cyclohexane and 2-butanol-cyclohexane and at five temperatures for the system 2-methyl-2-propanol-cyclohexane. A conspicuous temperature and concentration dependence of the maximum value of enthalpy of mixing was found for the latter system. Heats of mixing of all three systems were correlated by the SSF equation. The results of correlation are comparable with the experimental error (0.5%) in the entire range of mole fractions of alcohols.

Heats of mixing of butanone and chloroform with alkanes: Binary systems

1978 ◽  
Vol 43 (3) ◽  
pp. 829-836 ◽  
Author(s):  
Ján Biroš ◽  
Antonín Živný ◽  
Julius Pouchlý
Keyword(s):  
Binary Systems ◽  
Heats Of Mixing

Reorientational dynamics of highly asymmetric binary non-polymeric mixtures – a dielectric spectroscopy study

2021 ◽  
Vol 23 (12) ◽  
pp. 7200-7212 ◽  
Author(s):  
Thomas Körber ◽  
Felix Krohn ◽  
Christian Neuber ◽  
Hans-Werner Schmidt ◽  
Ernst A. Rössler
Keyword(s):  
Dielectric Spectroscopy ◽  
Spectroscopy Study ◽  
Concentration Dependences ◽  
Temperature Dependences ◽  
Reorientational Dynamics

Two separated relaxations α1 and α2 with different temperature dependences are identified in the mixtures. They are attributed to the dynamics associated with the high-Tg (α1) and the low-Tg component (α2) with distinct Tg concentration dependences.

scholarly journals Accounting for Cooperativity in the Thermotropic Volume Phase Transition of Smart Microgels

Gels ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 42
Author(s):  
Simon Friesen ◽  
Yvonne Hannappel ◽  
Sergej Kakorin ◽  
Thomas Hellweg
Keyword(s):  
Phase Transition ◽  
Interaction Parameter ◽  
Quantitative Description ◽  
Water Molecules ◽  
Volume Phase Transition ◽  
Network Chain ◽  
Solvent Interaction ◽  
Volume Phase ◽  
The Cross ◽  
Interaction Parameter Χ

A full quantitative description of the swelling of smart microgels is still problematic in many cases. The original approach of Flory and Huggins for the monomer–solvent interaction parameter χ cannot be applied to some microgels. The reason for this obviously is that the cross-linking enhances the cooperativity of the volume phase transitions, since all meshes of the network are mechanically coupled. This was ignored in previous approaches, arguing with distinct transition temperatures for different meshes to describe the continuous character of the transition of microgels. Here, we adjust the swelling curves of a series of smart microgels using the Flory–Rehner description, where the polymer–solvent interaction parameter χ is modeled by a Hill-like equation for a cooperative thermotropic transition. This leads to a very good description of all measured microgel swelling curves and yields the physically meaningful Hill parameter ν. A linear decrease of ν is found with increasing concentration of the cross-linker N,N′-methylenebisacrylamide in the microgel particles p(NIPAM), p(NNPAM), and p(NIPMAM). The linearity suggests that the Hill parameter ν corresponds to the number of water molecules per network chain that cooperatively leave the chain at the volume phase transition. Driven by entropy, ν water molecules of the solvate become cooperatively “free” and leave the polymer network.

Selection of surfactants as main components of ecological wetting agent for effective extinguishing of forest and peat-bog fires

2014 ◽  
Vol 68 (6) ◽  
Author(s):  
Joanna Rakowska ◽  
Krystyna Prochaska ◽  
Bożena Twardochleb ◽  
Monika Rojewska ◽  
Bożenna Porycka ◽  
...  
Keyword(s):  
Binary Systems ◽  
Quantitative Description ◽  
Dynamic Contact ◽  
Dynamic Surface Tension ◽  
Contact Angles ◽  
Wetting Agent ◽  
Active Components ◽  
Dynamic Surface ◽  
Model Surfaces ◽  
Main Components

AbstractThe results of research into obtaining an ecological wetting agent for wildfires are presented. First, measurements of the equilibrium and dynamic surface tension for anionic and non-ionic commercial surfactants and their binary mixtures were conducted. Next, the parameters of adsorption facilitating a quantitative description of the process in both binary systems as well as single-component solutions were estimated. In addition, the static and dynamic contact angles on model surfaces with different hydrophobicity were studied (glass, polyethylene, pressed peat). In a few mixed systems, a synergism in reducing the critical micelle concentration and/or a synergy of the ability to wetting model surfaces was identified. Next, research into the sorptivity and wettability of peat (loose and pressed) was conducted. It was found that non-ionic and anionic surfactants exhibit different abilities in respect of foaming and moistening of peat. From an analysis of the preliminary results, the surface-active components were selected to obtain a wetting agent composition. The wettability and adsorption characteristics and an evaluation of the foaming ability using solutions of the prepared compositions were tested. The effectiveness of the wetting composition thus obtained was confirmed in the laboratory and in field firefighting. The test results confirmed the better wettability and sorptivity on peat and the effectivity for combating wildfires, compared with some typical commercial products.

Thermodynamics of complex formation in binary liquid mixtures: application to systems containing acetonitrile

1977 ◽  
Vol 55 (16) ◽  
pp. 2980-2992 ◽  
Author(s):  
John W. Lorimer ◽  
David E. Jones
Keyword(s):  
Binary Systems ◽  
Liquid Mixtures ◽  
Binary Liquid Mixtures ◽  
Binary Complex ◽  
Binary Liquid ◽  
Binary Complexes ◽  
Excess Gibbs Energies ◽  
Thermodynamics Of Complex Formation ◽  
Volumes Of Mixing ◽  
Self Association

Equations for enthalpies and volumes of mixing are derived from thermodynamic association theory for complex binary liquid mixtures containing self-associating species and binary complexes. The various species can interact through general non-specific interactions of the simple mixture type.The equations, along with equations for the excess Gibbs energy, are applied to experimental data on excess Gibbs energies, heats, and volumes of mixing for the three binary systems formed from acetonitrile, carbon tetrachloride, and chloroform. The data require a theoretical model that involves two types of self-association of acetonitrile, one type of self-association of chloroform and formation of a binary complex CH3CN•2CHCl3. Thermodynamic parameters for the various types of association and interaction are derived by constrained least-squares methods, and provide a unified picture of the thermodynamic properties of these mixtures.

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