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

Normal Alkanes, Multialkane Synthetic Model Mixtures, and Real Petroleum Waxes: Crystallographic Structures, Thermodynamic Properties, and Crystallization

“…(ii) With the concentration increase of C 7 , the solid which crystallizes is a phase whose orthorhombic structure is different from the triclinic or monoclinic structure of pure C 26 and C 28 , respectively (Appendix 1 in the Supporting Information). This phase, observed by X-ray diffraction in equilibrium with the liquid, is isostructural to the orthorhombic intermediate solid solution β′′ 1 of the consecutive C n binary molecular alloys, especially in the (C 26 /C 28 ) system: 42 the chemical analysis shows that the concentration of this β" phase which forms the first deposits is greater in C 28 . 198 The crystallization of the β′′ intermediate solid solution explains the following notable phenomenon, observed by Ghogomu et al, 200,202 Provost et al, 199 and Flo ¨ter et al: 212 the addition of one long C n (0 < xC n < 0.1) to a short one (C n-1 or C n-2 ) increases the solubility of the latter (C n-1 or C n-2 ) in the solvents; thus, as shown by all these authors, the solubility of each binary heavy C n mixture in a light solvent is greater than the solubility of the corresponding hypothetical ideal mixtures (Figure 18).…”

“…Since then, the crystalline structures, as well as the thermodynamic data of pure C n 's and of the synthetic model mixtures consisting of two, three, four or five C n 's, 26,41,42,44,59,66,123,133, have been the subject of numerous publications. The literature results, obtained before 1960, have been reviewed by Mnyukh, 3 an exhaustive bibliography of the papers previous to 1971 has been presented by Turner, 53 the structural parameters of pure C n 's have been given by Heyding et al, 24 and the monograph of Srivastava et al 54 concerns more particularly the C n polymorphism.…”

“…The structure of the pure normal alkanes (hereafter denoted by C n ) has been the subject of several articles in the literature. − In the solid state, the stable configuration of the mol...…”

Improved Sensitivity in the Thermal Investigation of Polymeric Nanophases by Measuring the Resonance Frequency Shift using an Atomic Force Microscope

“…It exists at room temperature as an orthorhombic structure and changes at 57.5 8C into a rhombohedral structure with a melting point at 60.8 8C. [23] DSC and RFM analyses resolve both transitions. The two peaks in the DSC curve are very close (Figure 3 a), at 60.4 and 62.9 8C, and must be accurately measured to avoid seeing only one broad peak.…”

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.…”