Adsorption and phase transition of alkanol and fluoroalkanol at electrified mercury/aqueous solution interface

Murakami, Ryo; Sakamoto, Hiroyasu; Hayami, Yoshiteru; Matsubara, Hiroki; Takiue, Takanori; Aratono, Makoto

doi:10.1016/j.jcis.2005.08.002

Cited by 7 publications

(5 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The interfacial tension γ was measured as a function of the total molality m and composition of HDFC 9 OH X 2 at 298.15 K under atmospheric pressure by the pendant drop method based on the shape analysis of pendant drops described elsewhere. , Here m and X 2 are defined by and where m 1 and m 2 are the molalities of FDFC 9 OH and HDFC 9 OH in hexane solution, respectively. Experimental error of the γ value was estimated within ±0.05 mN m -1 .…”

Section: Methodsmentioning

confidence: 99%

Effect of ω-Hydrogenation on the Adsorption of Fluorononanols at the Hexane/Water Interface: Miscibility in the Adsorbed Film of Fluorononanols

et al. 2005

Self Cite

View full text Add to dashboard Cite

The interfacial tension of the hexane solution of 1H,1H-perfluorononanol (FDFC9OH) and its omega-hydrogenated analogue, 1H,1H,9H-perfluorononanol (HDFC9OH), against water was measured as a function of the total molality and composition of the mixture at 298.15 K under atmospheric pressure. The existence of omega-dipole in HDFC9OH makes the interfacial density larger in the gaseous and expanded states and smaller in the condensed state compared to FDFC9OH. The phase diagram of adsorption (PDA) was constructed, and the excess Gibbs energy of adsorption (gH,E) was calculated at each state in order to discuss quantitatively the miscibility of FDFC9OH and HDFC9OH in the adsorbed film. We found that the gH,E value is negative in the gaseous state, while it is positive and increases with decreasing interfacial tension in the condensed state. These results are explained mainly by the balance of two effects induced by mixing of two alcohols: (1) Reduction of repulsive interaction between omega-dipoles aligning parallel in the adsorbed film because of the increase in mean distance between HDFC9OH molecules. (2) The loss of effective dispersion interaction between hydrophobic chains due to the fact that the oblique orientation of HDFC9OH molecules at the interface is mixed with the perpendicular one of FDFC9OH. We concluded that the factor (2) is negligible compared to the factor (1) in the gaseous and expanded films and exceeds the factor (1) in the condensed film, in which molecules are closely packed.

show abstract

Section: Methodsmentioning

confidence: 99%

Effect of ω-Hydrogenation on the Adsorption of Fluorononanols at the Hexane/Water Interface: Miscibility in the Adsorbed Film of Fluorononanols

et al. 2005

Self Cite

View full text Add to dashboard Cite

show abstract

“…The γ value was calculated by the following equation normalγ = V normalΔ normalρ g F / r where V is the volume of a drop, Δρ is the density difference between air and the aqueous solution, g is the local acceleration of gravity, r is the capillary radius, and F is the correction factor, respectively. However, γ of the aqueous solutions of HMIMBr, HMIMBF 4 , and the HMIMBr−HMIMBF 4 mixture was measured by the pendant drop method based on the drop shape analysis described elsewhere as a function of the total molality m̂ m̂ = m Br 0.2em + 0.2em m 1 , Im 0.2em + 0.2em m BF 4 0.2em + 0.2em m 2 , Im = 2 m − 1 + 2 m 2 and the mole fraction X̂ 2 of the second component, HMIMBF 4 , X̂ 2 = false( m BF 4 0.2em + 0.2em m 2 , Im false) / m̂ where m 1,Im and m 2,Im are the molality of imidazolium cations dissociated from HMIMBr and HMIMBF 4 . The experiments were done at 298.15 K under atmospheric pressure.…”

Section: Methodsmentioning

confidence: 99%

Miscibility and Distribution of Counterions of Imidazolium Ionic Liquid Mixtures at the Air/Water Surface

et al. 2009

Self Cite

View full text Add to dashboard Cite

The miscibility and distribution of Br(-) and BF(4)(-) ions of imidazolium ionic liquid mixtures, 1-hexyl-3-methylimidazolium bromide (HMIMBr) + 1-hexyl-3-methylimidazolium tetrafluoroborate (HMIMBF(4)), at the air/water surface were investigated by surface tensiometry and the total-reflection XAFS (TRXAFS) method. Tensiometry showed that the surface density of BF(4)(-) was much larger than that of Br(-), the adsorbed films of the HMIMBr-HMIMBF(4) mixture were greatly enriched in BF(4)(-) at all surface tensions, and the excess Gibbs energy of adsorption was positive. However, TRXAFS revealed that the Br ions were all in the free-Br state solvated by six water molecules in the mixed adsorbed film. Entropy-originated nonideal mixing, where a kind of segregation of the counterion distribution takes place in the interfacial region, was suggested in the mixture.

show abstract

“…Interfacial tension γ was measured as a function of total molality m and composition of TFC 10 OH X 2 at 298.15 K under atmospheric pressure by the pendant drop method. , Here m and X 2 are defined by and where m 1 and m 2 are the molalities of DFC 8 OH and TFC 10 OH in hexane solution, respectively. The experimental error of γ value was within ±0.05 mN m -1 .…”

Section: Methodsmentioning

confidence: 99%

Effect of the Partial Hydrogenation of Hydrophobic Chains on the Mixing of Fluoroalkanols in an Adsorbed Film at the Hexane/Water Interface

et al. 2008

Self Cite

View full text Add to dashboard Cite

The mixed adsorbed film of 1H,1H-perfluorooctanol (DFC8OH) and 1H,1H,2H,2H-perfluorodecanol (TFC10OH) at the hexane/water interface was studied on the basis of interfacial tension measurement and its thermodynamic data analysis. An adsorbed film at any composition of the mixed system as well as those of pure DFC8OH and TFC10OH systems exhibits three states: the gaseous, expanded, and condensed states. Construction of the phase diagram of adsorption clarified that DFC8OH and TFC10OH mix almost ideally in the gaseous and expanded states. On the contrary, the excess Gibbs energy of adsorption g H,E value evaluated in the condensed state was positive. These results are explained by considering the following two factors: (1) The mixing of binary alcohols is accompanied by the loss of dispersion interaction energy due to the difference in extent of fluorination of hydrophobic chains and in their chain length and increases the g H,E value. (2) Since the interchange energy concerning the interaction between dipoles with different dipole moments is negative, the mixing of these alcohols reduces the repulsive force between hydrophilic groups and thus leads to a decrease in the g H,E value. In the gaseous and expanded states, both of above two factors are not effective. On the other hand, the positive g H,E value in the condensed state is attributable to more effective dispersion interaction than the dipole−dipole interaction in short molecular distance, and so factor 1 becomes dominant. Comparison of the g H,E value of the present system with that of the homologous TFC10OH−TFC12OH mixture leads us to a conclusion that the hydrogenation on β-carbons in hydrophobic chains affects appreciably the balance of interactions between hydrophilic and hydrophobic groups which governs the mixing of molecules in adsorbed films.

show abstract

Adsorption and phase transition of alkanol and fluoroalkanol at electrified mercury/aqueous solution interface

Cited by 7 publications

References 39 publications

Effect of ω-Hydrogenation on the Adsorption of Fluorononanols at the Hexane/Water Interface: Miscibility in the Adsorbed Film of Fluorononanols

Effect of ω-Hydrogenation on the Adsorption of Fluorononanols at the Hexane/Water Interface: Miscibility in the Adsorbed Film of Fluorononanols

Miscibility and Distribution of Counterions of Imidazolium Ionic Liquid Mixtures at the Air/Water Surface

Effect of the Partial Hydrogenation of Hydrophobic Chains on the Mixing of Fluoroalkanols in an Adsorbed Film at the Hexane/Water Interface

Contact Info

Product

Resources

About