Authors:Y. Li, G. Fei, Z. Honglin, L. Zhen, Z. Liqiang, and L. Ganzuo
The power–time curves of micellar formation of two anionic surfactants, sodium laurate (SLA) and sodium dodecyl sulfate (SDS),
in N,N-dimethyl acetamide (DMA) in the presence of various long-chain alcohols (1-heptanol, 1-octanol, 1-nonanol and 1-decanol)
were measured by titration microcalorimetry at 298 K. The critical micelle concentrations (CMCs) of SLA and SDS under various
conditions at 298 K were obtained based on the power–time curves. Thermodynamic parameters (
) for micellar systems at 298 K were evaluated according to the power–time curves and the mass action model. The influences
of the number of carbon-atom and the concentration of alcohol were investigated. Moreover, combined the thermodynamic parameters
at 303, 308 and 313 K in our previous work and those of 298 K in the present work for SLA and SDS in DMA in the presence of
long-chain alcohols, an enthalpy–entropy compensation effect was observed. The values of the enthalpy of micellization calculated
by direct and indirect methods were made a comparison.
Authors:Samira Mousa, Amal Altakrory, M. Abdel Raouf, and A. Alian
The effect of water-miscible alcohols and acetone on the extraction and separation of Cd and Zn chlorides by TOPO was systematically
investigated. The maximum extraction of Zn chloride with 0.1 M TOPO decreases in the order: acetone>methanol>ethanol>2-propanol>2-butanol.
For alcohols, the sequence of decreasing extractability is thus parallel to the order of their dielectric constants. This
can be explained by the increase of HCl extraction by TOPO in the same direction. The presence of additives in the polar phase
prevents the formation of a bulky white precipitate encountered during extraction of ZnCl2 from pure aqueous solutions. A decrease of Cd chloride extraction was generally noticed in presence of additives; this is
more noticeable for the longer chain alcohols. The highest separation factor (E for ZnCl2 and CdCl2 in 0.48M HCl is obtained from 30% methanol (13.8 compared to about 3.8 in absence of methanol) and from 10–20% acetone where
it reaches 30.
Authors:Zbigniew Czech, Robert Pełech, Krzysztof Zych, and Jolanta Świderska
alkenes, longchainalcohols and acrylate monomers.
The general thermal degradation mechanism of acrylic copolymers based on alkyl methacrylates includes random main-chain scission and side chain reactions. As a result of random main-chain scission
Authors:Rosiane M. C. Farias, Marta M. Conceição, Roberlúcia A. Candeia, Marta C. D. Silva, Valter J. Fernandes Jr., and Antonio G. Souza
-chain acids, but long-chainalcohol, show lower viscosities than esters of long- and short-chain alcohol. Saturated esters with high melting point have little influence in the kinematic viscosity at low temperatures. Analyses of kinematic viscosity at 40 °C