Micromixing in chemical reactors can be characterized through test reactions that are sensitive to mixing. A new pair of parallel competitive reactions, including acid–base neutralization and diethyl oxalate hydrolysis, is proposed in this work. It has clear principles and high sensitivity to micromixing with quantitative accuracy and operational simplicity. The measurement results obtained from stopped-flow spectra show that the alkaline hydrolysis of diethyl oxalate follows second-order kinetics, and the rate constant conforms to the Arrhenius equation k₂ = 2.331 × 10⁸ exp(−26.92 × 10³/RT) (L/mol/s). The estimated half-life of hydrolysis is approximately 3 × 10⁻⁴ s under the selected concentration combinations, which provides significant advantages for the micromixing assessment in the strong turbulent fluid environment. In the same stirred tank, the critical feed time of new test reaction is shorter than that of the Villermaux–Dushman reaction. Overall, this work provides practical ideas for screening other desired esters for fast hydrolysis to construct more test reactions for micromixing.

中文翻译：

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一种用于微量混合的新型高灵敏度测试反应：草酸乙酯的酸碱中和和碱水解


化学反应器中的微混合可以通过对混合敏感的测试反应来表征。这项工作提出了一对新的平行竞争反应，包括酸碱中和和草酸二乙酯水解。它具有明确的原理和对微量混合的高度敏感性，具有定量准确性和操作简单性。从停流光谱获得的测量结果表明，草酸二乙酯的碱性水解遵循二级动力学，速率常数符合阿伦尼乌斯方程 k ₂ = 2.331 × 10 ⁸ exp（−26.92 × 10 ³ /RT） （L/mol/s）。在选定的浓度组合下，估计的水解半衰期约为 3 × 10 ⁻⁴ s，这为强湍流环境中的微混合评估提供了显着优势。在同一个搅拌罐中，新测试反应的临界进料时间短于 Villermaux-Dushman 反应。总的来说，这项工作为筛选其他所需的酯类以进行快速水解以构建更多的微混合测试反应提供了实用思路。