School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, P.R. China.
Anal Chem. 2021 Sep 28;93(38):12987-12994. doi: 10.1021/acs.analchem.1c02710. Epub 2021 Sep 14.
Process analysis of heterogeneous catalytic reactions such as lignin depolymerization is essential to understand the reaction mechanism at the molecular level, but it is always challenging due to harsh conditions. Herein, we report an operando process analysis strategy by combining a microbatch reactor with high-resolution mass spectrometry (MS) via a reactor-integrated electrospray ionization (R-ESI) technique. R-ESI-MS expands the applications of traditional in situ MS to a heterogeneous and high-pressure liquid-phase system. With this strategy, we present the evolution of a series of monomers, dimers, and oligomers during lignin depolymerization under operando conditions (methanol solvent, 260 °C, ∼8 MPa), which is the first experimental elucidation of a progressive depolymerization pathway and evidence of repolymerization of active monomers. The proposed R-ESI-MS is crucial in probing depolymerization intermediates of lignin; it also provides a flexible strategy for process analysis of heterogeneous catalytic reactions under operando conditions.
杂化催化反应（如木质素解聚）的过程分析对于在分子水平上理解反应机制至关重要，但由于条件苛刻，这一直是一个挑战。在此，我们通过将微反应池与通过反应器集成电喷雾电离（R-ESI）技术的高分辨率质谱（MS）相结合，报告了一种操作过程分析策略。R-ESI-MS 将传统原位 MS 的应用扩展到了多相高压液相体系。通过该策略，我们在操作条件下（甲醇溶剂、260°C、约 8 MPa）展示了木质素解聚过程中一系列单体、二聚体和低聚物的演变，这首次从实验上阐明了渐进解聚途径，并证实了活性单体的再聚合。所提出的 R-ESI-MS 对于探测木质素解聚中间体至关重要；它还为操作条件下杂化催化反应的过程分析提供了一种灵活的策略。
