Roibu Anca, Fransen Senne, Leblebici M Enis, Meir Glen, Van Gerven Tom, Kuhn Simon
Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, 3001, Leuven, Belgium.
Sci Rep. 2018 Apr 3;8(1):5421. doi: 10.1038/s41598-018-23735-2.
Coupling photochemistry with flow microreactors enables novel synthesis strategies with higher efficiencies compared to batch systems. Improving the reproducibility and understanding of the photochemical reaction mechanisms requires quantitative tools such as chemical actinometry. However, the choice of actinometric systems which can be applied in microreactors is limited, due to their short optical pathlength in combination with a large received photon flux. Furthermore, actinometers for the characterization of reactions driven by visible light between 500 and 600 nm (e.g. photosensitized oxidations) are largely missing. In this paper, we propose a new visible-light actinometer which can be applied in flow microreactors between 480 and 620 nm. This actinometric system is based on the photoisomerization reaction of a diarylethene derivative from its closed to the open form. The experimental protocol for actinometric measurements is facile and characterized by excellent reproducibility and we also present an analytical estimation to calculate the photon flux. Furthermore, we propose an experimental methodology to determine the average pathlength in microreactors using actinometric measurements. In the context of a growing research interest on using flow microreactors for photochemical reactions, the proposed visible-light actinometer facilitates the determination of the received photon flux and average pathlength in confined geometries.
将光化学与流动微反应器相结合，能够实现比间歇式系统效率更高的新型合成策略。提高光化学反应机理的可重复性和理解程度需要诸如化学光量测定法等定量工具。然而，由于微反应器的光程较短且接收的光子通量较大，适用于微反应器的光量测定系统选择有限。此外，用于表征500至600纳米可见光驱动反应（如光敏氧化反应）的光量计基本缺失。在本文中，我们提出了一种可应用于480至620纳米流动微反应器的新型可见光光量计。该光量测定系统基于二芳基乙烯衍生物从闭环形式到开环形式的光异构化反应。光量测定测量的实验方案简便易行，具有出色的可重复性，并且我们还提出了一种计算光子通量的分析估算方法。此外，我们提出了一种利用光量测定测量来确定微反应器中平均光程的实验方法。在对使用流动微反应器进行光化学反应的研究兴趣日益浓厚的背景下，所提出的可见光光量计有助于确定受限几何结构中接收的光子通量和平均光程。
