For the synthesis of coumarin derivatives using the Pechmann condensation scheme, an acidic ionic liquid catalyst, abbreviated as [EBsImH][HSO₄], was prepared from the ring opening of 1,4‐butanesultone by 1‐ethylimidazole, followed by the addition of 1 equiv. H₂SO₄(c). The [EBsImH][HSO₄]‐catalyzed Pechmann condensation reactions proceeded smoothly in a batch setup, with recyclable [EBsImH][HSO₄] showing great catalytic activity. The acidic ionic liquid catalyst [EBsImH][HSO₄] was recovered from EtOAc/H₂O extraction of the product mixture, where the H₂O layer was worked up and dried for reuse in consecutive runs of the Pechmann condensation reactions, maintaining >85% conversion for four times. The catalytic reactions were also carried out in a microfluidic flow setup. The flow parameters, the reactant molar amounts, and the additional H₂SO₄ as a modifying acid catalyst were optimized in the current case study. A minimum conversion rate of 2.8 g/hr of coumarin derivatives was demonstrated.

中文翻译：

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Pechmann缩合反应在微流系统中香豆素衍生物的合成：案例研究

为了使用Pechmann缩合方案合成香豆素衍生物，从1，4-丁磺酸内酯与1-乙基咪唑的开环反应中制备了一种酸性离子液体催化剂，缩写为[EBsImH] [HSO ₄ ]。 1当量 H ₂ SO ₄（c）。的[EBsImH] [HSO ₄ ] -催化的在间歇设置顺利pechmann缩合反应的反应，使用可回收[EBsImH] [HSO ₄ ]表现出极大的催化活性。从EtOAc / H _2中回收酸性离子液体催化剂[EBsImH] [HSO ₄ ]O萃取产物混合物，在其中处理H ₂ O层并干燥以在Pechmann缩合反应的连续运行中重复使用，保持＞ 85％的转化率四次。催化反应也以微流体流动装置进行。在当前案例研究中，优化了流量参数，反应物摩尔量以及作为改性酸催化剂的附加H ₂ SO ₄。香豆素衍生物的最低转化率为2.8克/小时。