Thermal properties of Dianin's compound and its adducts.
Date
1990
Authors
Zakrzewski, Marek.
Journal Title
Journal ISSN
Volume Title
Publisher
Dalhousie University
Abstract
Description
Clathrates are multicomponent materials in which one type of molecule forms a host lattice in which the guest molecules reside. In general, investigations of clathrates afford the opportunity to compare various properties of diluted guest molecules with their properties in their pure (bulk) form.
The origin of the unusual thermal conductivities of clathrate hydrates (which cannot exist without a guest) has been attributed recently to the interactions of low-frequency optic modes of the guest molecules with the lattice acoustic modes.
4-p-Hydroxyphenyl-2,2,4-trimethylchroman (Dianin's compound), forms many different clathrates by crystallization from appropriate solvent/guests. It is an unusual clathrate in that it also exists in its unsolvated form. The purpose of this work was to investigate the effect of the presence and type of guest on the thermal conductivity of Dianin's clathrate.
Unsolvated Dianin's compound and its ethanol and carbon tetrachloride adducts have been investigated.
The following properties have been measured for Dianin's compound and its ethanol and carbon tetrachloride adducts: heat capacity (by adiabatic calorimetry); lattice parameters (by variable-temperature x-ray powder diffraction); elastic constants (ethanol adduct only; by Brillouin spectroscopy); velocity of sound (unsolvated Dianin's compound and its ethanol adduct; by the ultrasonic pulse technique); thermal conductivity (unsolvated Dianin's compound and its ethanol adduct; by the steady state method). The thermal expansion and Gruneisen parameters derived from these measurements indicate the importance of the guest species in the anharmonicity of the interactions. The Debye temperatures for unsolvated Dianin's compound and its ethanol adduct were determined. Three different models for thermal conductivity are discussed. The results favour the guest-host resonance model but show the (unexpected) result that the unsolvated lattice has a similar (but less pronounced) resistance to heat flow. The thermal conductivity for the CCl$\sb4$ adduct of Dianin's compound was calculated.
Thesis (Ph.D.)--Dalhousie University (Canada), 1990.
The origin of the unusual thermal conductivities of clathrate hydrates (which cannot exist without a guest) has been attributed recently to the interactions of low-frequency optic modes of the guest molecules with the lattice acoustic modes.
4-p-Hydroxyphenyl-2,2,4-trimethylchroman (Dianin's compound), forms many different clathrates by crystallization from appropriate solvent/guests. It is an unusual clathrate in that it also exists in its unsolvated form. The purpose of this work was to investigate the effect of the presence and type of guest on the thermal conductivity of Dianin's clathrate.
Unsolvated Dianin's compound and its ethanol and carbon tetrachloride adducts have been investigated.
The following properties have been measured for Dianin's compound and its ethanol and carbon tetrachloride adducts: heat capacity (by adiabatic calorimetry); lattice parameters (by variable-temperature x-ray powder diffraction); elastic constants (ethanol adduct only; by Brillouin spectroscopy); velocity of sound (unsolvated Dianin's compound and its ethanol adduct; by the ultrasonic pulse technique); thermal conductivity (unsolvated Dianin's compound and its ethanol adduct; by the steady state method). The thermal expansion and Gruneisen parameters derived from these measurements indicate the importance of the guest species in the anharmonicity of the interactions. The Debye temperatures for unsolvated Dianin's compound and its ethanol adduct were determined. Three different models for thermal conductivity are discussed. The results favour the guest-host resonance model but show the (unexpected) result that the unsolvated lattice has a similar (but less pronounced) resistance to heat flow. The thermal conductivity for the CCl$\sb4$ adduct of Dianin's compound was calculated.
Thesis (Ph.D.)--Dalhousie University (Canada), 1990.
Keywords
Chemistry, Physical.