Structural behaviour of molecular alloys: n-pentacontane (n-C50H105)-n-pentacosane (n-C25H52); n-pentacontane (n-C50H102)-n-tricosane (n-C23H48) at room temperature

This paper displays a study of binary mixtures of n-alkanes whose ratio of chain length is around two. The systems composed of n-tricosane (n-C23H48)- n-pentacontane (n-C50H102) and n-pentacosane (n-C25H52)-n-pentacontane (n-C 50H102) have been studied by means of X-ray analyses. These latter, perform ed at room temperature, showed in both cases, the existence of a large doma in where the phases characteristic of each pure component coexist. These mi xtures obey Kravchenko's rule relative to the solubility of the n-alkanes a ccording to the chain length of each component. The mixtures studied do not form an intermediate solid solution. In other words, there is no particula r arrangement of the shorter molecules inside the crystallographic unit of the longer. (C) 2001 Elsevier Science Ltd. All rights reserved.