Thermodynamic Properties of the n-Alkanes C19H40 to C26H54 and Their Binary Phase Diagrams

Phase diagram ofn-hexacosane andn-octacosane: experimental determination and calculation

“…This evolution has been observed in all the binary (43)(44)(45)(46)(47)(48)53) and ternary (49) mixtures of C n with 19 < n < 27.…”

“…This solid solution, hereafter denoted β , has an orthorhombic structure, and is identical to the one already observed in many binary and ternary n-alkanes systems, (43)(44)(45)(46)(47)(48)(49)53) or in paraffinic crude oil. (50)(51)(52) .…”

“…The β(Fmmm) phase has already been observed in oddnumbered pure n-alkanes (1,2,16,17,22,72) and in many n-alkanes systems. (43)(44)(45)(46)(47)(48)(49)51) When the characteristic peaks of the β phase disappear completely at T = 321.5 K, the rotator state RI of the β phase is detected by a small shift in the β phase (020) line. At T = 324.2 K, the line (020) of the β-RI phase disappears, and the major line characterizes the α-RII rotator phase.…”

“…In this paper, n-alkanes C n H 2n+2 are denoted by C n where n is the number of carbon atoms in the chain. In our laboratory, we are currently engaged in thermodynamic and structural studies of the liquid and solid phases of pure n-alkanes, (42) the (solid + liquid), and (solid + solid) equilibria in binary, (43)(44)(45)(46)(47)(48) ternary, (49) and multicomponent mixtures (50)(51)(52) of n-alkanes. Using the results already obtained, Dirand et al (53) highlighted a general behaviour of the thermodynamic and structural properties of consecutive binary n-alkanes (19 < n < 27), and deduced the following conclusion: existence of orthorhombic intermediate solid solutions, phenomenological laws for the succession of these intermediate phases when the composition varies, evolution of an intermediate solid solution with increase in temperature, the appearance of another orthorhombic phase, and rotator phases.…”

Modelling Phase Equilibria in Systems with Organic Solid Solutions

“…Reports on the formation of alloys, or solid solutions, of organic compounds, although still rare, have been appearing regularly in the last few years for aromatic compounds, such as substituted benzenes and naphtalenes [1][2][3], pyrene and anthracene [4][5][6], for carbohydrates [7], terpenes [8], neopentane derivatives [9][10] and fulerenes, besides solid solutions of C 60 with C 70 [11][12] solid solutions of C 60 in sulphur have been reported [13]. Nevertheless it is among the molecules with long n-alkyl chains such as n-alcohols [14], fats [15], soaps [16] and alkanes [17][18][19][20] that solid solutions appear more frequently. Although most of these alloys are still just interesting academic curiosities, these new materials seem quite promising and interesting applications for some of them have been identified.…”