Accurate determination of the photon flux is of major importance to evaluate and characterize photochemical reactor setups. Knowing the photon flux ensures reproducible reactor operation and facilitates predictable scale-up. Over the past years, flow reactors have proven to be the key enabling technology for photochemistry to become relevant on production scales. This is mainly due to the mitigation of the limited penetration depth of photons in typical batch reactors. However, due to the practical drawbacks of the widely accepted standard for photon flux determination (ferrioxalate actinometry) concerning precipitation and gas formation at higher conversion, reliable actinometry in flow reactors is still challenging. In this paper, three practical approaches for the ferrioxalate-based determination of the photon flux are presented, which address these problems. These “dimmed emitter,” “segment-based,” and “time-resolved” methods thus allow photon flux determination in flow reactors with higher irradiated volumes and more powerful light sources, which is of utmost importance in the context of future scale-up.

中文翻译：

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实用的草酸铁光度法测定面向生产的光流反应器中的光子通量

光子通量的准确测定对于评估和表征光化学反应器装置至关重要。了解光子通量可确保可重复的反应器操作并有助于可预测的放大。在过去的几年里，流动反应器已被证明是光化学在生产规模上变得相关的关键使能技术。这主要是由于减轻了典型间歇反应器中光子的有限穿透深度。然而，由于广泛接受的光子通量测定标准（草酸铁光度测定法）在较高转化率下有关沉淀和气体形成的实际缺陷，流动反应器中可靠的光度测定法仍然具有挑战性。在本文中，提出了三种基于草酸铁测定光子通量的实用方法，解决了这些问题。因此，这些“调光发射器”、“基于分段”和“时间分辨”方法允许在具有更高照射体积和更强大光源的流动反应器中确定光子通量，这在未来扩大规模的背景下至关重要.