The surface-active properties and emulsification ability of sodium α-sulfonated fatty acid esters, CmH2m+1CH-(SO3Na)COOCnH2n+1, were studied as a function of the hydrophobic alkyl chainlength in the fatty acid (m=8−16) and the alcohol (n=8−18). As
a result, it was discovered that sodium α-sulfonated fatty acid esters have a structural effect on the Krafft point different
from that of amphiphiles with short alkyl chains. Moreover, some of the α-sulfonated fatty acid esters have quite low interfacial
tensions, as well as non-foaming properties, which depend upon the total (m+n) number of carbon atoms in the alkyl chains. 相似文献
The measurements of viscosity are reported for seven binary mixtures of acrylonitrile (AN) with ethanenitrile (EN), methyl acetate (MA), ethyl acetate (EA), n-butyl acetate (BA), dimethylformamide (DMF), dimethylacetamide (DMA), and dimethyl sulphoxide (DMSO) at 303.15 K temperature. The viscosity data have been correlated with the equations of Grunberg and Nissan; Hind, McLaughlin, and Ubbelohde; Tamura and Kurata; Katti and Chaudhri; McAllister; Heric and Brewer; and of Auslaender. The relations between the viscosity deviations , excess Gibbs energy of activation G*E of viscous flow, and the intermolecular interaction in these mixtures are discussed. 相似文献
“Conjunct oligomerization” of propylene or the isopentane–propylene alkylation catalyzed by an excess of 95% sulfuric acid
was performed in two consecutive steps. First di-isopropylsulfate was prepared by interaction of sulfuric acid with propylene.
The ester was then either decomposed at room temperature in the presence of the 5–10 molar excess of 95% acid or was used
in the acid-catalyzed alkylation of isopentane. In situ1H and 13C NMR study of the reaction mixture of “conjunct oligomerization” indicated that the diester participates in two equilibria
with sulfuric acid. The first one transforms the diester into a monoester. The second equilibrium corresponds to protonation
of the monoester with an excess of sulfuric acid. This converts a minor fraction of the mono-alkylsulfate into isopropyl carbenium
ions that are only weakly solvated with sulfuric acid: C3H7HSO4 + H2SO4 ⇄ C3H7+ H2SO4 + HSO4−. The subsequent reactions of alkyl carbenium ions with the non-protonated alkylsulfate result in final products of “conjunct
oligomerization” while in the presence in the reaction mixture of isopentane, alkylation with the predominant formation of
C8 branched paraffins takes place. A very low yield of propane indicates a minor role of hydride transfer in alkylation. Another
unexpected result is the absence in both reaction mixtures of propylene. These findings are in contradiction with the classical
mechanism of isoparaffin–olefin alkylation by Schmerling. Therefore, an alternative mechanism of this reaction is suggested
via a direct alkylation of isopentane with the mono-alkylsulfate.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
A series of reverse Y‐shaped surfactants containing aromatic and aliphatic linkers to combine two short hydrocarbon chains and one carbohydrate head group was prepared. Liquid crystalline behavior, air–water interfacial properties, and efficiency as an emulsifier was investigated for each reverse Y‐shaped surfactant. All reverse Y‐shaped surfactants mediated higher emulsion stabilities for water‐in‐oil compared to common typical reference surfactants, reflecting an improved ability to cope with a curvature towards water. The introduction of a benzene ring into the linker substantially increased the affinity of the surfactant for hydrophobic media, resulting in improved emulsion stability for both water‐in‐oil and oil‐in‐water. 相似文献
A new visible light‐initiated 1,5‐hydride radical shift strategy has been developed to enable the one‐step functionalization of both a C(sp3) Br bond and a C(sp3) H bond adjacent to the same carbon atom. This visible light photoredox catalysis offers a mild and straightforward access to diverse five‐membered carbocyclic ring‐fused polycyclic hydrocarbons with high turnover numbers (TONs; up to 4.93×103) and broad substrate scope.