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Relations propriétés - structure - composition - distribution de mélanges n-aires de normal-alcanes synthétiques et industriels

Abstract : This document displays the results on severa! properties of multi-alk:anes mixtures and the effect on structural state and on sorne properties of n-alkanes adding to this type of mixture. First, major results on pure alk:anes and their molecular alloys is presented. Then, severa! multi-alkanes product of "normal logarithmic" distribution were specially studied. It appears that such mixture forms a single solid solution ~ · isostructural to the ordered intermediate phase of the n-alk:anes alloys (binary or ternary). From the crystallographic c-parameter of this solid solution, it is possible to determine the average chain length of the molecules in the crystallographic unit-cell. Finally, the product can be considered as a hypothetical orthorhombic pure n-alkane. Sorne of their chemical and physical properties (thermal dilation coefficient, density and mechanical magnitudes) are also measured. Moreover, the n-alkanes distribution of one mixture was modified by pure component adding. Thus, two systems were studied : commercial multialk: ane product with eicosane or pentacontane. The isopleth section of the both systems were established by means of X-ray diffraction and differentiai thermal analyses on molecular allo ys. Examinations of the results show existence of a large domain where the phase ~ ' and the phase characteristic of the pure alkane added coexist (triclinic phase y0-C20H42 or orthorhombic phase ~0-C50Hto2) . In the both case, the solubility limits of the alk:ane added in the commercial multi-alk:ane product were established. Compilation of the X-ray analyses at various temperature and differentiai thermal analyses allowed to propose both isopleth sections, which are of eutectic or peritectic type. The prope1ties of an alloy of each isopleth were also compared to those of the initial product. In conclusion, addition of pure component to multi-alkanes mixtures induces structural transformation and significant modifications to the physico-chemical properties
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Contributor : Thèses Ul <>
Submitted on : Thursday, March 29, 2018 - 1:38:35 PM
Last modification on : Monday, October 19, 2020 - 2:05:47 PM


  • HAL Id : tel-01752210, version 1



Manuelle Pierre. Relations propriétés - structure - composition - distribution de mélanges n-aires de normal-alcanes synthétiques et industriels. Autre. Institut National Polytechnique de Lorraine, 2002. Français. ⟨NNT : 2002INPL056N⟩. ⟨tel-01752210⟩



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