SYSTEMATIC DESIGN OF CHEMICAL OSCILLATORS .64. DESIGN OF PH-REGULATED OSCILLATORS
SYSTEMATIC DESIGN OF CHEMICAL OSCILLATORS .64. DESIGN OF PH-REGULATED OSCILLATORS
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DOI：
10.1021/ar00176a004
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发表时间：
1990-08-01
影响因子：
18.3
通讯作者：
EPSTEIN, IR
中科院分区：
文献类型：
--
作者：
RABAI, G;ORBAN, M;EPSTEIN, IR
氢离子浓度是水溶液中几乎所有反应中最重要和最容易测量的量之一，从无机系统到生物体中的复杂过程。人们可能会认为，测量和理解pH值变化的努力将在振荡化学反应的研究中发挥重要作用，几乎所有这些反应都发生在水溶液中。令人惊讶的是，直到最近，H+作为化学振荡器中的主要物质的作用在很大程度上被忽视了。在这个帐户中，我们讨论了一个新的家庭的振荡反应组成的系统，显示大振幅（几个pH单位）的pH振荡在无缓冲溶液中，但只有单调的行为在酸碱缓冲液的存在下。这种系统可以使用基于简单数学模型的程序来设计。它们与热动力学振荡器和神经振荡器都具有强烈的相似性。在化学振荡实验研究的早期阶段，使用氧化还原或卤离子特定电极通过分光光度法或电位法对系统进行监测。氧化还原电位的测量，占主导地位的这些研究是相当少的信息比pH值，因为前者给出了一个混合的电位，而后者是物种特异性。在1985年以前，很少有出版物提到振荡反应中的pH变化。在研究连二亚硫酸钠水溶液热分解过程中，发现了[H+]随时间变化的几个极值。3尽管Bray-Liebensky 4（H2 O2-IO 3”，[H+]= 0.01-0.1 M）和Belousov-Zhabotinskii 5（BZ：有机还原剂的溴酸盐氧化，[H+]= 0.1-1 M）反应的酸性介质为pH测量创造了不利条件，但在这些众所周知的振荡系统中发现了pH的小幅周期性变化6，7。在这样的系统中pH的变化并不密切参与振荡现象，而是
The hydrogen ion concentration is one of the most important and most easily measured quantities in nearly all reactions in aqueous solution, from inorganic systems to complex processes in living organisms. One might expect then that efforts to measure and understand pH changes would have played a major role in the study of oscillatory chemical reactions, nearly all of which occur in aqueous solution. Surprisingly, the role of H+ as a major species in chemical oscillators has been largely ignored until quiterecently. In this Account, we discuss a new family of oscillating reactions consisting of systems that display large-am-plitude (several pH units) pH oscillations in unbuffered solution, but only monotonic behavior in the presence of acid-base buffers. Such systems can be designed using procedures based on simple mathematical models. They bear stronganalogies to both thermokinetic and neural oscillators.In the early stages of the experimental investigation of chemical oscillations, systems were monitored either spectrophotometrically or potentiometrically, with re-dox or halogen ion specific electrodes. The redox po-tential measurements that dominated these studies are considerably less informative than the pH, since the former give a mixed potential, while the latter is species specific. Few publications before 1985 mention pH changes in an oscillatory reaction. Several extrema in [H+] as a function of time were reported in a study of the thermal decomposition of sodium dithionite in aqueous solution. 3 Despite the acidic media of the Bray-Liebhafsky4 (H2O2-IO3",[H+]= 0.01-0.1 M) and the Belousov-Zhabotinskii5 (BZ: brómate oxidationof an organic reductant,[H+]= 0.1-1 M) reactions, which create unfavorable conditions for pH measurement, small-amplitude periodic changes in pH have been found6, 7 in these well-known oscillatory systems. The variation of pH in such systems is not intimately involved in the oscillatory phenomenon, but rather