皂类液膜振荡器

Soap Liquid Membrane Oscillators

实验发现了一类新型液膜振荡器,在油水两相之间进行成皂反应的过程中,界面附近出现了长时间规则的大幅度pH振荡,将W/O两相体系换成W1/O/W2三相体系,振幅从0.50pH明显提高到2.88pH.其中水相组成为CTAB溶液及NaOH溶液,油相组成为油酸的煤油溶液.同时,此类液膜振荡体系中亦存在明显的电势振荡和电导率振荡.为深入了解机理,进行了浓度影响测定,电极位置和种类的变化以及辅助实验等,提出了普遍化的机理,并进行了实验振荡曲线的拟合对比.这个机理指出,在膜反应批量进行的条件下,当反应速率与扩散成比例时,便会产生规则的周期现象.在一价皂液膜振荡器的基础上,通过替换或添加各种金属盐,形成了各类高价皂液膜振荡器,测定了反应过程中pH、电势及电导率的变化.经过同类化学振荡器的比较研究,结合金属离子与酸根之间的络合作用,得出了其中的一些规律.

A new liquid membrane oscillator has been discovered experimentally, in the reaction of producing soap between the two phases of oil and water, pH oscillations appeared near the interface lasting a long time with large amplitude. When the system of W/O two phases was changed by three phases of W-1/O/W-2, the amplitude changed from 0.50 pH to 2.88 pH. The constitution of the liquid membrane oscillator is two aqueous solutions of CTAB and NaOH, respectively and an oil phase of kerosene solution of oleic acid. In addition, obvious oscillations of electric potential and conductivity have also been discovered in the liquid membrane oscillator. In order to probe the oscillation mechanism more deeply, the effect of concentration, the change of position and kind of electrodes, as well as auxiliary experiments have been carried out and a generalizated mechanism has been given. The mechanism pointed out that under the condition of membrane reaction carrying to some extent, when the reaction rate is proportion to diffusion velocity, a regular periodic phenomena can be produced. A comparison between simulation of experimental curves and mechanistic formula was also engaged. On the base of mono valence soap oscillator, various kinds of higher valence ones were formed by substitution or addition of transition metals. The change of pH, electric potential and conductivity during the reaction were monitored. With comparison study of the same kind of chemical oscillators, some conclusions were obtained from the consideration of the coordination between metal and acid radical.