Mechanism of nitromethane liquid membrane oscillator containing sodium oleate

Szpakowska, Maria; Magnuszewska, Aneta; Nagy, O. B.

doi:10.1016/j.jcis.2008.05.059

Cited by 9 publications

(5 citation statements)

References 25 publications

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“…It is admitted that the transformation of one species into another is governed by the laws of deterministic chemical kinetics. This imparts high flexibility and efficiency to the mathematical analysis of complex systems such as ion transport through liquid membranes , or liquid membrane oscillators. , …”

Section: Resultsmentioning

confidence: 99%

Molecular Mechanism and Chemical Kinetic Description of Nitrobenzene Liquid Membrane Oscillator Containing Benzyldimethyltetradecylammonium Chloride Surfactant

Szpakowska

Płocharska-Jankowska

2009

J. Phys. Chem. B

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Nonlinear oscillations of electric potential differences caused by mass transfer of benzyldimethyltetradecylammonium chloride through a nitrobenzene liquid membrane containing picric acid are investigated. The physical chemistry of this liquid membrane oscillator is described in detail, and limitations of applicability of some physicochemical laws are pointed out. It is shown that the oscillations are of chemical origin. The role of the accompanying hydrodynamic effects is critically examined. In order to understand the oscillation mechanism at the molecular level, a new mechanistic scheme based on ion pairs mass transfer is proposed. Oscillations appear at the membrane-aqueous acceptor phase interface, and they are caused by the autocatalytic adsorption of surfactant molecules to this interface. Inclusion of cross-catalytic molecular events shows interesting coupling between diffusion fluxes and the two oscillating subsystems present. It is demonstrated that the proposed mechanistic scheme is quite general and versatile. Time evolution of the oscillator is described by using the laws of deterministic chemical kinetics. The results obtained by numerical integration of the corresponding system of first-order autonomous differential equations are in fairly good agreement with experimental time series. It is postulated accordingly that the nonlinear oscillations observed for liquid membrane systems are originating from molecular events and are further amplified by hydrodynamic effects.

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Section: Resultsmentioning

confidence: 99%

Molecular Mechanism and Chemical Kinetic Description of Nitrobenzene Liquid Membrane Oscillator Containing Benzyldimethyltetradecylammonium Chloride Surfactant

Szpakowska

Płocharska-Jankowska

2009

J. Phys. Chem. B

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“…It has been shown that the oscillations of electrical potential across the liquid membrane are accompanied by synchronous oscillations of interfacial tension. , Therefore, in all proposed models the oscillations are ascribed to an abrupt adsorption of the surfactant at the liquid interface followed by its gradual desorption. − However, the physical mechanisms causing this adsorption/desorption interchange have not been clarified so far. It is also not clear why in systems with rather similar composition the oscillations can occur either at donor/membrane or at acceptor/membrane interface.…”

Section: Introductionmentioning

confidence: 99%

Auto-Oscillation of Surface Tension: Effect of pH on Fatty Acid Systems

Kovalchuk

Vollhardt

2010

Langmuir

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Spontaneous nonlinear oscillations of surface tension produced by transfer of either octanoic or nonanoic acids from a droplet situated in the bulk water to the air/water interface are studied experimentally. It is shown that the oscillation amplitude decreases significantly with the increase of pH of aqueous phase. At pH > 6.5, detectable oscillations for the two fatty acids studied do not exist. The results are discussed in terms of the mechanism proposed recently for spontaneous oscillations produced by transfer of nonionic surfactants.

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“…For the system with anionic surfactant-sodium oleate and butanol present in the left aqueous phase, and the liquid membrane being the solution of 2,2 0 -bipyridine in nitromethane-the oscillations were suggested to be caused by adsorption and desorption of both alcohol and surfactant at the same, m/a interface, the whole process being controlled by the slow diffusion of these species across the liquid membrane [34]. Thus, independently of the kind of surfactant, the same m/a interface appears to be responsible for the oscillations.…”

Section: Recent Developments In Liquid Membrane Oscillatorsmentioning

confidence: 99%

Liquid Membrane and Other Membrane Oscillators

Orlik

2012

Self-Organization in Electrochemical Systems II

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In complement to the hydrodynamic instabilities driven by surface tension gradients, enclosed in Sects. 5.4-5.7, we describe here the dynamics of the liquid-liquid interface, formed by two fluids of very limited miscibility, e.g., by water and 2-nitropropane. First reports on this type of dynamical systems have been published by Dupeyrat and Nakache [1,2], and later analogous studies were continued also by .A representative example of that type of the systems is the water-2-nitropropane system [3]. The key point is that each phase should contain the dissolved species that is significantly better soluble in the other phase. In this way the initial state of such system is far from equilibrium and the natural trend to decrease the free Gibbs energy is the flow of each dissolved species to the other phase. In the example described here, the aqueous phase contains initially the hexadecyltrimethylammonium bromide (or cetyltrimethylammonium bromide, CTAB) the large organic CTA + cation of which exhibits, due to its hydrophobicity, higher affinity to the organic phase. In turn, the phase of 2-nitropropane contains initially dissolved picric acid (HA), better soluble and also partly dissociating in water (pK a % 0.2).When these two phases are brought into contact, with the organic layer placed over the aqueous layer, the oppositely directed flows of CTAB and HPi begin. This transport is associated with subtle oscillations of various characteristics: pH of aqueous solution, interfacial potential drop (Fig. 6.1), and interfacial tension. The latter phenomena are easily detectable as visible oscillations of the meniscus at the interface of both liquids. It is interesting that under such non-equilibrium conditions the presence of surfactant (CTAB) does not depress the surface tension gradients, but on the contrary, it is responsible for their periodic temporal variations.Yoshikawa and Matsubara [3] have proposed the mechanism of these oscillatory phenomena. First, one should note that CTA + cations in both phases form micelles above certain critical CTA + concentrations. Those micelles exhibit inverted M. Orlik, Self-Organization in Electrochemical Systems II, Monographs in Electrochemistry,

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Mechanism of nitromethane liquid membrane oscillator containing sodium oleate

Cited by 9 publications

References 25 publications

Molecular Mechanism and Chemical Kinetic Description of Nitrobenzene Liquid Membrane Oscillator Containing Benzyldimethyltetradecylammonium Chloride Surfactant

Molecular Mechanism and Chemical Kinetic Description of Nitrobenzene Liquid Membrane Oscillator Containing Benzyldimethyltetradecylammonium Chloride Surfactant

Auto-Oscillation of Surface Tension: Effect of pH on Fatty Acid Systems

Liquid Membrane and Other Membrane Oscillators

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