Proton Magnetic Resonance Absorption in High Temperature Phases of Anhydrous Sodium Stearate

Abstract

Nuclear magnetic resonance spectra of anhydrous sodium stearate have been observed between 114° and 320 °C. The observed changes in line width and second moment suggest a grouping of the mesomorphic phases into a waxy group in which a lattice structure is preserved for the polar ends of the molecules and a group consisting of the neat and liquid phases in which diffusion takes place freely.

Nuclear Magnetic Relaxation and the Biological Membrane

“…The sharp reduction in second moment at -ISO°C could be due to onset of motion of the -NMe 3 + group; this would be consistent with the absence of a similar reduction of second moment in phosphatidyl ethanolamines (Chapman and Salsbury, 1966). At higher temperatures, line sharpening is attributed to oscillation of the -CH2-groups in the fatty acid chains (Salsbury and Chapman, 1968) as postulated to occur in a number of soap phases (Grant and Dunell, 1960;Barr and Dunell, 1964;van Putte, 1970).…”

Thermal analysis and calorimetry of some fatty acid sodium soaps

“…The enthalpy and the entropy of the subneat-neat and perhaps of the neat isotropie transition has an alternating character, similar to that of the melting of fatty acids (12) and paraffins (13) but, of course, much smaller. According to the current views (13-15), this would suggest a different methyl end-group packing for the odd and even chains because from the complete miscibility in this region there is no reason to expect differences in subcell packing between odd and even chains If this is true, the chains THE JOURNAL OF THE AMERICAN OIL CHEMISTS' SOCIETY u 45 are less "liquid-like" in character (4,11,16) than generally accepted; they would at least be fixed at the two ends. It is interesting now to compare the total amount of heat necessary to melt the soap with the melting heat of paraffins (13) and fatty acids (12) (Fig.…”

Ionic Liquid Crystals

“…281 The dynamic disorder of the alkyl chains in the mesophases of anhydrous soaps has been investigated by 1 H NMR. [282][283][284][285] For each successive phase encountered with increasing temperature an increased level of chain motion was observed. The methyl end of the alkyl chain rotates even below room temperature.…”

“…The thermal behavior of the whole series of lithium alkanoates from lithium formate (1 carbon atom, HCOOLi) to lithium eicosanoate (20 carbon atoms, C 19 H 39 COOLi) has been studied by Ferloni and Westrum . The dynamic disorder of the alkyl chains in the mesophases of anhydrous soaps has been investigated by 1 H NMR. − For each successive phase encountered with increasing temperature an increased level of chain motion was observed. The methyl end of the alkyl chain rotates even below room temperature.…”