Frerichs Glen A, Jones James, Huang Xiaohe, Gebrekidan Mulurhab, Burch Jacob, Cheng Mei Yuan, Chen Yuwei
Department of Chemistry , Westminster College , 501 Westminster Avenue , Fulton , Missouri 65251 , United States.
J Phys Chem A. 2019 Feb 21;123(7):1303-1310. doi: 10.1021/acs.jpca.8b11222. Epub 2019 Feb 12.
No single-phase system has been previously reported to give significant pH oscillations in a closed (batch) reactor. We report here sustained pH oscillations in batch for the Belousov-Zhabotinsky reaction using much lower [H] and much higher [BrO] than in traditional studies of this reaction. In fact, pH oscillations were obtained in the presence of only BrO, malonic acid (MA), and Mn. The amplitude, frequency, and duration of oscillations tend to depend primarily on the ratio of [BrO] to [MA]. A critical part of the proposed mechanism involves the reversible formation of a manganese(III) complex with bromomalonic acid, followed by two-electron oxidation to tartraric acid and Mn. Estimates of the corresponding rate constant values for these reactions have been obtained by simulation. It is suggested that the presence of a supercatalytic reaction in H may be a sufficient, if not necessary, requirement for the occurrence of pH oscillations in a batch system.
此前没有报道过任何单相系统在封闭（间歇）反应器中能产生显著的pH振荡。我们在此报告，在Belousov-Zhabotinsky反应的间歇过程中，使用比该反应传统研究中低得多的[H]和高得多的[BrO]，实现了持续的pH振荡。事实上，仅在存在BrO、丙二酸（MA）和Mn的情况下就获得了pH振荡。振荡的幅度、频率和持续时间主要取决于[BrO]与[MA]的比例。所提出机制的一个关键部分涉及锰（III）与溴丙二酸形成可逆络合物，随后双电子氧化生成酒石酸和Mn。通过模拟获得了这些反应相应速率常数的估计值。有人提出，H中存在超催化反应可能是间歇系统中发生pH振荡的一个充分条件（即使不是必要条件）。
