Acta Chimica - Models in Chemistry 130. (1993)

1. szám - RESEARCH ARTICLES - Iordache, O.–Corriou, J. P.–Valentin, G.–Pons, M. N.–Pethő A.: Intermittent interfacial transfer: a dyadic model

IORDACHE et al.: INTERMITTENT INTERFACIAL TRANSFER: A DYADIC MODEL 3 Experimental An interesting intermittent system was discovered by Dupeyrat and Nakache [1] and then studied by many other authors. Different other intermittent interfacial transfer systems have been studied also in chemical engineering and in physical literature [9], [10]. The intermittent or oscillating system described here consisted of an aqueous solution of hexadecyltrimethylammonium bromide, 5 x 10 4 M (phase 1), an aqueous solution of KCl, 3M (phase Г) and an organic solution of iodine (1.5 xlO"4 M saturated with potassium iodide) dissolved in nitrobenzene (phase 2). The organic phase is introduced into an U-shaped apparatus made of glass tubing, then the aqueous phases 1 and Г are introduced separately in each branch of the U-tube so that one cell is occupied by the KC1 solution and the by the other surfactant solution (Fig.l). Experiments were performed at different ambient temperatures. Two reference Ag/AgCl electrodes connected to a millivoltmeter were used to measure the potential differences between the aqueous phases. The electrodes were placed about 10 mm from the interface. Typical records are shown in Tables I and II. The domains in which the system displays bursts of spikes separated by quiet spells were specifically studied regarding to their evident similarity with electrophysiological signals [4]. Table I Recorded intermittent signals, case 1 Fig. 1. Experimental set-up Time (min) 0 1.8 3.3 3.5 4.6 9.6 13.7 14.8 15.4 47.2 Potential (mV) 128 104 104 88 80 72 72 80 64 4.56 Acta Chimica Hungarica - MODELS IN CHEMISTRY 130, 1993

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