Highly efficient oxidation of ethyl lactate (ELA) to ethyl pyruvate (EP) was realized over TS-1 in the presence of aqueous H₂O₂ (30 wt %) at low temperature without other solvent. A 100% ELA conversion and 97.8% EP yield were obtained at 50 °C after 9 h. The conversion rate of ELA is sensitive to the reaction temperature. High reaction temperature (70 °C) leads to an increase in conversion rate of ELA but causes the fast hydrolysis and decarboxylation of EP to form byproducts of acetic acid and CO₂. On the basis of the characterization (pyridine-FTIR and UV–vis) and reaction results, active species of Ti(OOH) were proven. In addition, a nonradical mechanism for conversion of ELA to EP for this catalytic system was proposed. By kinetic analysis, the formation of Ti(OOH) is confirmed as the rate-determining step. The apparent activation energy (103.4 kJ mol^–1) was also obtained. Furthermore, TS-1 was highly stable for the oxidation of ethyl lactate. There were almost no change in ELA conversion and EP yield throughout 10 reaction runs.

中文翻译：

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TS-1在温和条件下将乳酸乙酯高效氧化为丙酮酸乙酯

在含水H ₂ O ₂（30 wt％）的存在下，在没有其他溶剂的情况下，在TS-1上实现了将乳酸乙酯（ELA）高效氧化为丙酮酸乙酯（EP）。9小时后，在50°C下获得100％的ELA转化率和97.8％的EP收率。ELA的转化率对反应温度敏感。高反应温度（70°C）导致ELA转化率提高，但会导致EP快速水解和脱羧，形成乙酸和CO ₂副产物。根据表征（吡啶-FTIR和紫外可见）和反应结果，证明了Ti（OOH）的活性物种。另外，提出了用于该催化体系的将ELA转化为EP的非自由基机理。通过动力学分析，确定Ti（OOH）的形成是确定速率的步骤。还获得了表观活化能（103.4 kJ mol ^–1）。此外，TS-1对于乳酸乙酯的氧化是高度稳定的。在整个10次反应运行中，ELA转化率和EP收率几乎没有变化。