The study examines Ni/ZSM-5 catalysts in vapor phase hydrogenation of levulinic acid (LA) under continuous flow conditions (ambient pressure, 210–250 °C). Advanced characterization revealed the interplay between Al and Ni. This was further reinforced by new approach of microkinetic modeling, which demonstrates a pioneering work on mathematical description of pulse H sorption, TPD kinetics, DRIFT-supported determination of sorption energy barriers and (de)sorption kinetics. The Ni/ZSM-5 (3.7 wt.% Ni, Si/Al = 28) emerged as the optimal choice for obtaining γ-valerolactone (GVL) as the desired product. Al-rich catalysts with high acid site amounts and low metallic Ni active site concentrations favored esterification, reducing hydrogenation activity, and impeding further hydrogenation of GVL to pentanoic/valeric acid (PA). To enhance PA formation, Ni/ZSM-5 (4 wt.% Ni, Si/Al = 750) with a high Si/Al ratio, was identified as crucial. The combination of described experiments and modelling is demonstrated beneficial for insightful investigation of the structure–activity relationship of Ni/ZSM-5 or any other mono/bi-functional catalysts.

中文翻译：

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乙酰丙酸气相加氢过程中 Ni/ZSM-5 的创新微动力学模型支持结构-活性分析


该研究考察了 Ni/ZSM-5 催化剂在连续流动条件（环境压力，210–250 °C）下乙酰丙酸 (LA) 气相加氢中的作用。先进的表征揭示了铝和镍之间的相互作用。微动力学建模的新方法进一步强化了这一点，该方法展示了脉冲 H 吸附的数学描述、TPD 动力学、DRIFT 支持的吸附能垒测定和（解）吸附动力学的开创性工作。 Ni/ZSM-5（3.7 wt.% Ni，Si/Al = 28）成为获得 γ-戊内酯 (GVL) 作为所需产品的最佳选择。具有高酸性位点数量和低金属镍活性位点浓度的富铝催化剂有利于酯化反应，降低加氢活性，并阻碍 GVL 进一步加氢为戊酸/戊酸（PA）。为了增强 PA 的形成，具有高 Si/Al 比的 Ni/ZSM-5（4 wt.% Ni，Si/Al = 750）被认为是至关重要的。事实证明，所述实验和建模的结合有助于深入研究 Ni/ZSM-5 或任何其他单/双功能催化剂的结构-活性关系。