Improved method for kinetic studies in microreactors using flow manipulation and noninvasive Raman spectrometry.
Improved method for kinetic studies in microreactors using flow manipulation and noninvasive Raman spectrometry.
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DOI：
10.1021/ja1102234
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发表时间：
2011-03
影响因子：
15
通讯作者：
Sergey Mozharov;A. Nordon;D. Littlejohn;C. Wiles;P. Watts;Paul H. Dallin;J. Girkin
中科院分区：
文献类型：
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作者：
Sergey Mozharov;A. Nordon;D. Littlejohn;C. Wiles;P. Watts;Paul H. Dallin;J. Girkin
设计了一种新方法来获取微流体系统中反应的动力学信息。与传统的克诺文格尔缩合反应程序相比，在获得数据所需的时间（减少五倍）和试剂的有效使用（减少十倍）方面，已经证明了其优势。该程序基于从低流速（例如，0.6 μL min(-1)）到高流速（例如，14 μL min(-1)）的阶跃变化以及流线末端的实时无创拉曼测量，无需沿微反应器通道移动测量探头即可获得特定位置的信息。为了验证该方法，采用两种不同的实验方法获得了有效反应级数 n 的值。使用这些 n 值，计算并比较速率常数 k。在 10 和 40 °C 下，由该方法得出的 k 值分别为 0.0356 ± 0.0008 mol(-0.3) dm(0.9) s(-1) (n = 1.3) 和 0.24 ± 0.018 mol(-0.1) dm(0.3) s(-1) (n = 1.1)，而使用更费力的传统方法是 0.0335 ± 10 °C 时为 0.0032 mol(-0.4) dm(1.2) s(-1) (n = 1.4)，40 °C 时为 0.244 ± 0.032 mol(-0.3) dm(0.9) s(-1) (n = 1.3)。新方法不仅限于拉曼光谱分析，还可以与不同的技术一起使用，这些技术可以合并到流路的末端以提供快速测量。
A novel method has been devised to derive kinetic information about reactions in microfluidic systems. Advantages have been demonstrated over conventional procedures for a Knoevenagel condensation reaction in terms of the time required to obtain the data (fivefold reduction) and the efficient use of reagents (tenfold reduction). The procedure is based on a step change from a low (e.g., 0.6 μL min(-1)) to a high (e.g., 14 μL min(-1)) flow rate and real-time noninvasive Raman measurements at the end of the flow line, which allows location-specific information to be obtained without the need to move the measurement probe along the microreactor channel. To validate the method, values of the effective reaction order n were obtained employing two different experimental methodologies. Using these values of n, rate constants k were calculated and compared. The values of k derived from the proposed method at 10 and 40 °C were 0.0356 ± 0.0008 mol(-0.3) dm(0.9) s(-1) (n = 1.3) and 0.24 ± 0.018 mol(-0.1) dm(0.3) s(-1) (n = 1.1), respectively, whereas the values obtained using a more laborious conventional methodology were 0.0335 ± 0.0032 mol(-0.4) dm(1.2) s(-1) (n = 1.4) at 10 °C and 0.244 ± 0.032 mol(-0.3) dm(0.9) s(-1) (n = 1.3) at 40 °C. The new approach is not limited to analysis by Raman spectrometry and can be used with different techniques that can be incorporated into the end of the flow path to provide rapid measurements.