Evaluation of the Vaporization, Fusion, and Sublimation Enthalpies of the 1-Alkanols:  The Vaporization Enthalpy of 1-, 6-, 7-, and 9-Heptadecanol, 1-Octadecanol, 1-Eicosanol, 1-Docosanol, 1-Hexacosanol, and Cholesterol at T = 298.15 K by Correlation Gas Chromatography

Abstract

The vaporization enthalpies and vapor pressures of 1-, 6-, 7-, and 9-heptadecanol, 1-octadecanol, 1-eicosanol, 1-docosanol, 1-hexacosanol and cholesterol at T = 298.15 K have been measured by correlation gas chromatography using as standards, the even carbon n-alkanols from 1-decanol to 1-octadecanol and 1-pentadecanol. Fusion enthalpies for the all of these compounds were either measured by DSC or obtained from the literature. Adjusted to T = 298.15 K, the fusion and vaporization enthalpies were combined to provide sublimation enthalpies. The sublimation enthalpies were compared to existing literature values. Agreement between the two sets of values when available was generally very good.

Structural Analysis of a Modern o/w-Emulsion Stabilized by a Polyglycerol Ester Emulsifier and Consistency Enhancers

“…In modern cosmetic emulsions, typically only 1-6 wt % consistency enhancers are used, and preferably part of the fatty alcohol is replaced by glyceryl stearate in order to provide a less waxy skin feel. Moreover, the emulsifier content in the "DAC" system was 7.5 wt % of PEG- (20)-stearate, which is also clearly above the typical emulsifier content of 1.5-5 wt % in modern cosmetic emulsions. Furthermore, Junginger's stearate cream either did not contain any oil, or in the case of the "DAB" and "DAC" system only very heavy waxes (petrolatum, soft paraffin) or oils (liquid paraffin), which is a substantial difference to most formulations relevant in applications today.…”

“…This can be attributed to the fact that pure stearyl alcohol has a higher melting point (59.6 • C) and a higher melting enthalpy (258 kJ kg −1 ) [20] than the emulsifier; consequently, its admixture to the emulsifier/water system leads to an increase in the melting temperature of the mixed bilayers.…”

Solid-liquid equilibrium of triolein with fatty alcohols

“…Also, data from the literature (Wesdorp, 1990;Ventolà et al, 2004;Nichols et al, 2006) was used for evaluation of the significance of these properties for modeling accuracy. Accounting for the immiscibility in the solid phase, the procedure described above was applied along the entire composition range for calculating the mixtures' melting points, assuming that either the light or the heavy component represents the pure solid phase.…”

“…Component properties taken from the literature (Wesdorp, 1990;Ventolà et al, 2004;Nichols et al, 2006) as well as the values obtained in this work are presented in Table 5. The values from the literature were also used with the modeling procedure presented above.…”

“…In addition, the effects of polymorphism could produce peaks that overlap or are too close, which disrupts the determination of enthalpy, especially for fatty alcohols, as discussed previously. Wesdorp (1990), b Ventolà et al (2004), c Nichols et al (2006).…”