The critical micelle concentration (CMC) for a series of cationic surfactants N-Alkyltrimethylammonium i.e. (C n TAC, n=12,14,16,18) have been determined by electrical conductivity and surface tension methods. The interaction of anionic dye Eriochrome Black T (EBT) with cetyl-trimethylammonium chloride and cetylpyridinium chloride (CPC) has been investigated spectrophotometrically. The binding constant (K b ) and the surface excess (Γ) were calculated. The results show that with increasing the surfactants alkyl chain lengths, CMC and minimum area (A min ) decreases, while the surface excess concentrations increase. It has been found that the binding constant of CPC is double -fold that than of the binding constant of cetyl-trimethylammonium chloride (C 16 TAC).
A series of alumina and silica supported molybdenum oxide catalysts were prepared using ammonium heptamolybdate at different loading levels (5 -20 wt% of molybdenum oxide) by the impregnating method. The total acidity of the solid catalysts was measured by means of potentiometric titration. The supported catalysts possess very strong acid sites (may be contain both Brønsted and Lewis acid sites). The total surface acidity was observed to increase dramatically with increasing of loading levels. However the surface acidity of alumina supported molybdena catalysts are found to be higher than surface acidity of silica supported molybdena catalysts. Sulfation modification remarkably enhances the surface acidity and increases the strength of acidity due to the inductive effect of S=O.
The gravimetric analysis of electrodeposited nickel is demonstrated using electrochemical quartz crystal microbalance (EQCM) where the nickel coatings come from a solution of the metal chloride salt separately in either a1choline chloride: 2 ethylene glycol (ethaline) or 1 choline chloride: 2 urea (reline) based ionic liquid. The possibility of adapting the Quartz Crystal Microbalance EQCM (which measures the mass attached to the electrode) to probe kinetics of electrochemically-driven solid state phase transformations has been explored in a Ni electrodeposition in absence and presence of complexing agents ethylene diamine en and acetylacetonate acac from both electrolytes ethaline and reline. The study shows that the current efficiency and the rate of deposition of nickel coatings obtained from ethaline and reline baths in absence of brighteners en and acac are different, and the addition of en and acac to both ionic liquid solutions results in a significant decrease current. And the associated growth rate will also be decreased, suggesting that the en acac stops the formation and growth of Ni nuclei. This suggests that the mechanism of growth is changed.
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