College of Chemical Engineering, China University of Mining and Technology, Xuzhou 221008, China.
J Phys Chem A. 2009 Oct 22;113(42):11295-300. doi: 10.1021/jp906040a.
Temperature oscillations and complex pH oscillations in the IO(3)(-)-SO(3)(2-)-S(2)O(3)(2-) system were observed in a continuously flow stirred tank reactor. During one period of oscillation, the temperature increases rapidly while the pH shows an extremely sharp change. High-amplitude pH oscillations undergo 1(1) complex oscillations (L(S), oscillations with L large peaks and S small peaks per period) to another kind of higher-amplitude regular oscillations upon increasing the concentration of sulfite step by step. Importantly, the longstanding experimental phenomena, the extraordinary temperature sensitivity of oscillatory behavior reported 20 years ago by Rabai and Beck, can be eliminated by premixing of sulfite and sulfuric acid before entering into the reactor, avoiding local acidification, which brings out fluctuation and temperature sensitivity. The temperature oscillations can be understood by taking into account the interaction between thermal effect of various reactions and heat transfer. Experimental observations, both temperature oscillations and 1(1)-type pH oscillations, are reproduced with a four-step Horvath model by addition of an energy-balance equation. This new detailed dynamical behavior would have potential applications in designing complex chemical waves and pH responsive gels with rhythmical motion.
在连续流动搅拌釜式反应器中观察到 IO(3)(-)-SO(3)(2-)-S(2)O(3)(2-) 体系中的温度振荡和复杂的 pH 振荡。在一个振荡周期中，温度迅速升高，而 pH 值则发生极其急剧的变化。随着亚硫酸盐浓度的逐步增加，高振幅 pH 振荡经历了 1(1) 种复杂的振荡（L(S)，每个周期的 L 峰高而 S 峰低）到另一种更高振幅的规则振荡。重要的是，通过在进入反应器之前预先混合亚硫酸盐和硫酸，可以消除 20 年前 Rabai 和 Beck 报道的长期实验现象，即振荡行为的异常温度敏感性，避免局部酸化，从而产生波动和温度敏感性。通过考虑各种反应的热效应和传热之间的相互作用，可以理解温度振荡。通过添加能量平衡方程，使用四步 Horvath 模型再现了温度振荡和 1(1)-型 pH 振荡的实验观察结果。这种新的详细动力学行为可能在设计具有节奏运动的复杂化学波和 pH 响应凝胶方面具有潜在应用。
