Calorimetric measurement of molar excess enthalpies of dilute solutions of ethylbenzene + higher n-alkanes

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

“…All these results 198,199,210 are in agreement with the research work of Chang et al, 206 Arenosa et al, 207 Doman-ska et al, 208,209 Ksiazczak et al, 101 Madsen et al, 211 and Ghogomu et al [202][203][204][205] The liquidus curve (Figure 16) can be calculated by models: the use of the ideal solution model is not appropriate to represent the experimental results, whereas the application of the expression of Buchowski et al, 213 for instance, gives good results for the binary systems C 23 , C 25 , C 26 , or C 28 in C 7 . 199 Moreover, Provost et al 198 have calculated the activity coefficients γ of C 26 and C 28 , in the liquid solution, for the binary systems C 26 /C 7 and C 28 /C 7 , using the standard thermodynamic relationship for equilibrium between a pure solid component and a liquid.…”

“…C n and Light Solvent. Solubility studies of the heavy pure C n 's in light solvents were described in the literature, for instance by Couthino et al, 197 Provost et al, 198,199 Ghogomu et al, [200][201][202][203][204][205] Chang et al, 206 Arenosa et al, 207 Domanska et al, [208][209][210] Ksiazczak et al, 108,121 Madsen and Boistelle, 211 Floter et al, 212 Buchowski et al, 213 and Mahmoud et al 214,215 These binary systems of C n 's, which have a high difference of chain length between the heavy solute and light solvent, respect Kravchenko's rules about their solubility for the solid state and display phase diagrams with no miscibility in the solid phase and eutectic solidification 198,199,208,211 (Figure 16):…”

“…As the crystallization of normal paraffin hydrocarbons in the middle distillate fuels and in petroleum cuts is of significant interest in petroleum technologies, studies have been carried out on the solubilities of pure C n 's and of their synthetic mixtures in organic solvents 121,168,[197][198][199][200][201][202][203][204][205][206][207][208][209][210][211][212][213][214][215][216] and on the structural and thermodynamic properties of model and real multicomponent paraffin waxes in order to seek adequate thermodynamic models to represent the behavior of petroleum cuts. 23,76,77, The aim of this review is to summarize current findings in the literature and to give complementary results obtained in recent years.…”

Estimation of the Enthalpy of Formation of Multialkane Synthetic Mixtures: Measurement by Mixing Calorimetry and Modeling by the UNIQUAC Model

“…To obtain the different thermodynamic properties involved with the dissolution of synthetic multi-C n samples in heptane, we represented the thermochemical cycle of the dissolution of a polyphasic mixture, at a given temperature T, in Figure 1. The following general equation was derived where ∆ diss H(mixture) is the dissolution enthalpy of the mixture in a solvent, ∆ diss H(C k ) is the dissolution enthalpy of the pure C n s of the mixture in the same experimental conditions, ∆ form H(φ j ) is the enthalpy of formation of φ j in the solid phase, ∆H liq exc is the excess enthalpy in the liquid phase, p is the C n number in the mixture, q is the phase According to literature results, 38,39 the enthalpy of mixing of C n s in the liquid phase is almost equal to zero and the mixing enthalpy [24][25][26]38 of two paraffinic complex liquid phases is always lower than 1 J‚g -1 ; thus, ∆H liq exc ) 0 for the multi-C n mixtures. In a previous paper, 39 we determined the enthalpies of dissolution in heptane of C n s with chain lengths ranging from 22 to 36 carbon atoms at ambient temperature (T ) 296.15 K) and highlighted (1) a linear relation between the enthalpies of dissolution and the n carbon atom number and (2) the athermal character of the mixing process of a C n in the liquid phase with a solvent of the same nature.…”

Variations of Dissolution Enthalpies of Pure n-Alkanes in Heptane as a Function of Carbon Chain Length

“…From this point of view, the measurements of the solubility of n -alkanes in various solvents, obtained by varying either the carbon chain length of the n -alkane or the nature of the solvent used (polar, apolar solvents or mixtures of solvents), are very numerous − because they constitute an essential data bank for the development of thermodynamic models able to represent the solubility equations or the solid/liquid equilibrium.…”