Ueber das Verhalten der fettsauren Alkalien und der Seifen in Gegenwart von Wasser. III. Die Seifen als Krystalloïde

Krafft, F.; H., Wiglow,

doi:10.1002/cber.18950280349

Cited by 74 publications

(15 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This behavior is well known in ionic surfactantwater systems (8)(9)(10)(11)(12)(13)(14)(15). The curd is a semicrystalline mesophase in which the surfactant molecules form lamellar structures.…”

Section: General Thermal Propertiesmentioning

confidence: 72%

The thermotropic phase behavior of ascorbyl palmitate: an infrared spectroscopic study

Sapper¹,

Cameron²,

Mantsch³

1981

Can. J. Chem.

177

143

View full text Add to dashboard Cite

The infrared spectra of aqueous potassium ascorbyl palmitate were studied as a function of temperature using Fourier transform infrared techniques. From a light scattering experiment the Krafft point of 0.1 M potassium ascorbyl palmitate was determined to be 48°C. The temperature-induced changes in infrared spectral parameters such as frequency and bandwidth characterize this Krafft point as a phase transition from a conformationally ordered, poorly hydrated solid phase, to an isotropic micellar phase. The phase transition of this "pseudosoap" occurs over a temperature range of about 1O0C, reflecting the progressive hydration of the solid upon micellization, a behavior typical of surfactants such as soaps. Chem. 59,2543Chem. 59, (1981. En utilisant les techniques infrarouges de la transformation de Fourier, on a etudie les spectres infrarouges des solutions aqueuses de palmitateascorbyle de potassium en fonction de la temperature. A partir d'un experience de dispersion de la lumiere, on a determine que le point Krafft pour une solution 0,l M de palmitateascorbyle de potassium est de 48°C. La temperature provoque des changements dans les parametres spectraux tels la frkquence et la largeur des bandes qui caracterisent ce point Krafft en tant que 1 transition de phase i partir d'une conformation ordonnee, ma1 hydratee dans la phase solide, jusqu'a une phase micellaire isotropique. La transition de phase de ce "pseudo" savon s e produit au dessus d'un intervalle de temperature de 10°C environ refletant ainsi I'hydratation progressive du solide lors de la formation des micelles, c'est un comportement typique des savons.

show abstract

Section: General Thermal Propertiesmentioning

confidence: 72%

The thermotropic phase behavior of ascorbyl palmitate: an infrared spectroscopic study

Sapper¹,

Cameron²,

Mantsch³

1981

Can. J. Chem.

177

143

View full text Add to dashboard Cite

show abstract

“…Hence, the bile salt solubility curve demonstrates a sharp break at the Krafft point because all monomers leaving the crystals are at concentrations above the CMC. The traditional explanation given for the CMT phenomenon is that the hydrocarbon part of the amphiphile becomes "melted" at the temperature of the CMT (16,17). This is not correct: the fused steroid skeleton of bile salts is as rigid below the CMT as above this temperature.…”

Section: Bile Salts: Solubility Properties Displayed Inmentioning

confidence: 93%

Bile Acids and Bile Salts: Ionization and Solubility Properties

Carey

1984

Hepatology

View full text Add to dashboard Cite

The number, position and orientation of nuclear OH substituents profoundly influence the equilibrium solubilities of undissociated bile acids in water. Estimates from several studies range from 5 x lo-' for lithocholic acid to 1.6 x M for ursocholic acid at 37OC. Fully dissociated sodium bile salts are extremely soluble in water, attaining values as high as 1 to 2 M . However, ionized unconjugated bile salts are appreciably less soluble than their glycine and taurine conjugates. In contrast to aqueous solutions of typical soaps and detergents, aqueous bile salt systems in concentrations beyond the micellar phase limit exhibit no liquid-crystalline phases. The critical micellar temperatures of the common di-and trihydroxy bile salts lie below O"C, hence most bile salts form micelles at all ambient temperatures. With many monohydroxy and certain uncommon dihydroxy bile salts, the critical micellar temperatures lie above body temperature, and a micellar phase is observed only at temperatures in excess of 50OC. The pKa' values of aqueous micellar concentrations of bile salts are influenced by the nuclear substituents, the state of conjugation and bile salt concentration. In contrast, the intrinsic thermodynamic pK'a values of all monocarboxylated bile salts in monomeric solution are similar, are not influenced by nuclear substituents and are equivalent to that expected for propionic acid (pKa' -4.8 to 5.0). These values can be deduced by extrapolation from acidimetric titrations of bile salts in aqueous methanol mixtures or from acidometric aqueous titration of the carboxylate groups of pansulfated bile salts which remain water soluble when the ionic group of the side chain is protonated. The precipitation pH values of the common protonated bile acids are influenced by bile salt concentration, the state of conjugation and the solubilizing capacity of bile salt micelles for the otherwise sparingly soluble undissociated bile acid species.Organic chemists have traditionally employed the term "bile acid" as a generic name for the cholanoic class of biological compounds (1). This nomenclature has been carried over into much of the biochemical and physiological literature (2). From the physical-chemical and pathophysiological viewpoint, it is crucial to distinguish undissociated or protonated bile acids (HA) from the dissociated or ionized bile salts (A-) because their physicalchemical and physiological properties are distinctly different (3) ( Table 1). Further, I believe it is preferable to confine the use of the term "bile a c i d for the HA species of cholanoic compounds irrespective of whether they are unconjugated (free) or conjugated with glycine or taurine. The term "bile salt" should therefore be employed to designate the common, Na+, K', Ca++, etc., salts of the anionic species irrespective of the state of conjugation.In Small's classification of biological amphiphiles based on surface and bulk interaction with water (4), bile acids are insoluble amphiphiles and bile salts are soluble amphiphiles. In simple terms...

show abstract

“…The Krafft phenomenon of the anesthetics is diswhere formation of surfactant aggregates begins to occur cussed in comparison with straight-chain surfactants. Then (1). At the Krafft point, the hydrated solid surfactant melts the effects of chemical structure and counterions on the and dissolves as micelles in water (2, 3), though there is an Krafft temperature are considered.…”

Section: Introductionmentioning

confidence: 99%

Differential Scanning Calorimetric Study on the Krafft Phenomenon of Local Anesthetics

Matsuki

Ichikawa

Kaneshina

et al. 1996

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

Ueber das Verhalten der fettsauren Alkalien und der Seifen in Gegenwart von Wasser. III. Die Seifen als Krystalloïde

Cited by 74 publications

References 2 publications

The thermotropic phase behavior of ascorbyl palmitate: an infrared spectroscopic study

The thermotropic phase behavior of ascorbyl palmitate: an infrared spectroscopic study

Bile Acids and Bile Salts: Ionization and Solubility Properties

Differential Scanning Calorimetric Study on the Krafft Phenomenon of Local Anesthetics

Contact Info

Product

Resources

About