17012-98-5Relevant academic research and scientific papers
Smectic liquid crystals from supramolecular guanidinium alkylbenzenesulfonates
Mathevet, Fabrice,Masson, Patrick,Nicoud, Jean-Francois,Skoulios, Antoine
, p. 2248 - 2254 (2007/10/03)
A homologous series of guanidinium alkylbenzenesulfonates from ethyl to tetradecyl were synthesized and characterised. Their thermotropic polymorphism was investigated by polarizing optical microscopy, differential scanning calorimetry, and dilatometry. The structure of the smectic liquid crystal phases obtained at high temperature with the compounds from octyl to tetradecyl was analysed by X-ray diffraction. The supramolecular assembling of the ionic species inside the smectic layers was investigated by infrared spectroscopy.
PROPRIETES PHYSICI-CHIMIQUES DE N-ALKYL P-BENZENE SULFONATES ALCALINS: TEMPERATURE DE KRAFFT ET CONCENTRATION CRITIQUE MICELLAIRE
Rouviere, Jacques,Faucompre, Bernard,Lindheimer, Marc,Partyka, Stanislas,Brun, Bernard
, p. 309 - 314 (2007/10/02)
The Krafft points (Tk) and the critical micellar concentrations (c.m.c.) on the alkali salts of n-alkyl-p-benzene sulfonates have been measured by solubility and conductivity experiments.For the sodium compounds, we observe a linear relationship between log10cmc and n the number of carbon atoms in the alkyl chain of the surfactant, a linear relationship between the Tk of the homologous surfactants studied and n.The substitution of sodium counter-ion by another alkali, decreases the Krafft point which seems to be correlated to the hydratation of the counter-ion.These data permit us to know the Tk and c.m.c. of homologous series of various amphiphiles.By treating the formation of micelles as analogous to phase separation, the determination of the variation of c.m.c. with temperature has been studied, these results have been converted into, enthalpy and free energy of micellization and these have been compared with corresponding values obtained from literature data.
Krafft Points of Anionic Surfactants and Their Mixtures with Special Attention to Their Applicability in Hard Water
Tsujii, Kaoru,Saito, Naoyuki,Takeuchi, Takashi
, p. 2287 - 2291 (2007/10/02)
The Krafft points of the sodium and calcium salts of typical anionic surfactants and their mixtures have been measured to examine their applicability in hard water.The pure model compounds of the linear alkylbenzene sulfonates, α-olefin sulfonates, and alkylpoly(oxyethylene) sulfates were synthesized and used for Krafft-point measurements.Among the above three types of surfactant, the alkylpoly(oxyethylene) sulfates are shown to be the best surfactant for their practical uses in hard water, since their sodium and calcium salts as well as their mixtures are readily soluble at room temperature.The Krafft point vs. composition curves observed in binary surfactant mixtures have been classified into two groups.In group I, there exists a minimum in the Krafft point at a certain composition, whereas the Krafft point varies monotonously with the composition change in group II.It is found from the composition analysis of the solid phase that both components are immiscible in group I but are completely miscible even in the solid phase in group II.The thermodynamic theory for freezing-point depression has been favorably applied to the Kraff point vs. composition curves in group I.Theoretical calculations for the Krafft point vs. composition curves (liquidus curve) and the corresponding solidus curves in group II have also been made, assuming the ideal solutions in both liquid (micellar) and solid phases.The calculated curves are in poor agreement with the observed ones probably because of the nonideality of the solution especially in the solid phase.
