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Journal of Thermal Analysis and Calorimetry

, Volume 107, Issue 3, pp 1301–1306 | Cite as

Activation energy (ΔG*), enthalpy (ΔH*), and entropy (ΔS*) of some indoles and certain of their binary mixtures

  • Mohan T. Hosamani
  • Narasimha H. Ayachit
  • D. K. Deshpande
Article

Abstract

Thermodynamic parameters, like, change of activation energy for dipole orientation (ΔG*), enthalpy (ΔH*), and entropy (ΔS*) of activation in the case of binary-, ternary-, etc. mixtures of polar molecules in pure liquid phase or in dilute solution phase in a non polar solvent helps in drawing certain quantitative conclusions regarding their relaxation behavior as to whether a single component is responsible for observed microwave absorption or a cooperative phenomenon (average) by all the dipoles of the mixture contribute to it. Dielectric relaxation behavior of polar molecules in a non-polar solvent, or mixtures of these substances at different microwave frequencies and over a range of temperatures and concentrations give a method of determining these quantities. Such an experimental investigation on verity of systems is necessary to draw quantitative conclusions regarding the system of the molecules which are not studied so as to examine if the results obtained are in favor or against the general conclusions already arrived at, in other systems. With this in view, systematic dielectric measurements in a range of temperatures are carried out at a single microwave frequency on a single weight fraction in benzene of the four substituted indoles, namely, 5-Bromoindole, 5-Fluoroindole, 2,3-Dimethylindole, 2,5-Dimethylindole and on binary (1:1) mixtures of 2,5-Dimethylindole + 5-Bromoindole and 2,3-Dimethylindole + 5-Fluoroindole in benzene as solvent at different temperatures. The results are presented and discussed.

Keywords

Dielectric relaxation Enthalpy Activation energy 

Notes

Acknowledgements

The authors (NHA and MTH) acknowledge the help and encouragement shown by their respective principals and managements in carrying out this work.

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Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2011

Authors and Affiliations

  • Mohan T. Hosamani
    • 1
  • Narasimha H. Ayachit
    • 2
  • D. K. Deshpande
    • 3
  1. 1.Department of PhysicsP C Jabin Science CollegeHubliIndia
  2. 2.BVB College of Engineering and TechnologyHubliIndia
  3. 3.Karnataka UniversityDharwadIndia

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