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The formation of microemulsions with triglycerides at ambient conditions can be improved by increasing the surfactant-water and surfactant-oil interactions. Therefore, extended surfactants were developed, which contain hydrophilic/lipophilic linkers. They have the ability to stretch further into the oil and water phase and enhance the solubility of oil in water. In this work, the phase behavior of a chosen extended surfactant (C(12-14)-PO(16)-EO(2)-SO(4)Na, X-AES) in H(2)O/D(2)O at high surfactant concentrations (30-100 wt %) and at temperatures between 0 and 90 °C is studied for the first time. The lyotropic liquid crystals formed were determined by optical microscopy, small-angle X-ray scattering (SAXS), and (2)H and (23)Na NMR, and a detailed phase diagram of the concentrated area is given. The obtained mesophases are a hexagonal phase (H(1)), at low temperatures and small concentrations, a lamellar phase (L(α)) at high temperatures or concentrations, a bicontinuous cubic phase (V(2)) as well as a reverse hexagonal phase (H(2)). To our knowledge, this is the first surfactant that forms both H(1) and H(2) phases without the addition of a third compound. From the (2)H NMR quadrupole splittings of D(2)O, we have examined water binding in the L(α) and the H(2) phases. There is no marked difference in the bound water between the two phases. Where sufficient water is present, the number of bound water molecules per X-AES is estimated to be ca. 18 with only small changes at different temperatures. Similar results were obtained from the (23)Na NMR data, which again showed little difference in the ion binding between the L(α) and the H(2) phases. The X-ray diffraction data show that X-AES has a much smaller average length in the L(α) phase compared to the all-trans length than in the case for conventional surfactants. At very high surfactant concentrations an inverse isotropic solution (L(2)), containing a small fraction of solid particles, is formed. This isotropic solution is clearly identified and the size of the reversed micelles was determined using (1)H NMR measurements. Furthermore, the solid particles within the L(2) phase and the neat surfactant were analyzed. The observed results were compared to common conventional surfactants (e.g., sodium dodecyl sulfate, sodium lauryl ether sulfate, and sodium dodecyl-p-benzene sulfonate), and the influence of the hydrophilic/lipophilic linkers on the phase behavior was discussed.

The formation of microemulsions with triglycerides under ambient conditions has been a challenge for scientists for many decades. For this reason, so-called extended surfactants were developed that contained hydrophilic/lipophilic linkers to stretch further into the oil and water phase, and enhance the solubility of triglycerides in water. Currently, only limited information about the properties of these surfactants and its behavior in water is available. Therefore, in this work, mixtures of a chosen extended surfactant (C(12-14)-PO(16)-EO(2)-SO(4)Na, X-AES) with H(2)O/D(2)O over the whole concentration range were studied by optical microscopy. A schematic phase diagram has been obtained, which shows two isotropic liquid phases at the lowest and highest surfactant concentrations. Furthermore, between the isotropic solutions, four liquid-crystalline phases occur: a hexagonal phase (H(1)), a lamellar phase (L(alpha)) with a change in birefringence, a bicontinuous cubic phase (V(2)), and a reverse hexagonal phase (H(2)). The structure of the micellar solution (L(1)) was determined by cryo-TEM, dynamic light scattering, and (1)H NMR, which gave information about the size, the aggregation number, and the area per molecule of the micelles. Liquid-crystal formation occurs from the micellar solution in two different ways. The first route appeared by increasing the temperature, going from an L(1) to an L(alpha) phase. By increasing the surfactant concentration (at low temperatures), a second route showed a transition from L(1) to H(1). In addition, the effect of sodium chloride on the cloud point of the extended surfactant was examined, indicating that small amounts of NaCl have no influence on the phase behavior. The monolayer behavior of the extended surfactant at the air-water interface was also determined. Despite its water solubility, an isotherm on the water subphase was found, showing slow kinetics of the molecules to go into the bulk. Thus, the determination of the cmc of the extended surfactant using conventional methods was found to be impossible.

Synthesis of Medium and Large Rings, XXVII1. - Chromatographic Separation of the Enantiomeric 3.6-Heptanophthalides. - A Contribution to the Problem of the Absolute Configuration of [nJ Paracyclophanecarboxylic Acids The partial chromatographic separation of the racemic title compound 1 (ee = 40%) was achieved on triacetylcellulose with ethanol using a recycling technique. Comparison of the CD spectra of (+)22365-1 with (+)22365-2 leads to the absolute configuration (P) for both compounds. This assignment is of interest in view of earlier configurational assignments for [n]paracyclophanecarboxylic acids.

The energy barrier to rotation about the C(sp2)C(aryl) single bond in non-planar N,N-dimethyl-, N,N-tetramethylene-, N,N-diisopropyl-2,6-difluorobenzamides and in N,N-dimethyl-2-chloro-6-fluorobenzamide was investigated by 19F{1H} NMR in the presence of an optically active shift reagent. The free energy of activation was calculated from the coalescence temperature of the fluorine signals; the calculation was accomplished using the simple, approximative equation and, also, by the graphical procedure including the (eigen) line width, i.e. without the broadening caused by two-site exchange. A distinct effect of the size of the N-substituents on the ΔGc‡values was observed, in accordance with expectation.

N-Aryl-4-pyridones 1–6 were synthesized by condensation of the corresponding 4-pyrone with anilines. The enrichment of the enantiomers was achieved by liquid chromatography on triacctylcellulose, enantiomeric purities of(+)-1 and (+ )-2 being measured by 1H-NMR in the presence of an optically active auxiliary. Barriers to partial rotation about the C-N bond in 1-4 were determined and compared with corresponding biphenyls.

Preparation and properties of the planar-chiral [2.2]phanes 1a – d and of the sulfone 2c are described. The enantiomers of the ester 1c have been separated on triacetylcellulose. The circular dichroism and the racemization barrier for the enantiomers have been determined. The X-ray analysis of 1c for the first time gives precise data on the spacial relationships in 1,10-dithia[2.2]metacyclophanes. Comparisons with the corresponding hydrocarbon skeleton 3 lead to conclusions as to the topomerization barrier in substituted [2.2]phanes dependent on the distance of the intraanular substituents.

A novel procedure for the measurement of enantiomeric purity P is derived, whereby the mixture to be analyzed is subjected to liquid chromatography (LC) on an optically active sorbent. Extensive peak overlap does not prohibit the application of the method, whereas the complete absence of separation does. In addition, the mixture is subjected to LC on an achiral sorbent. The same photometer and polarimeter detections are used for both experiments. At the same time, an x/y recorder plots the rotation angle α versus the absorbance A, thus generating the slopes Cm and C+ in Fig. 1 which result in P = Cm/C+. – Optically active samples of 1, 2, 3, and 4 were analyzed for P. The findings agree satisfactorily with the results of other methods.

Racemic methylneophylphenyltrityltin (1) could be resolved completely by chromatography on microcrystalline cellulose triacetate coupled with fractional crystallizations. The influence of temperature on the chromatographic separation of compound (1) and of t-butylmethylphenyltrityltin (2) is described.