Dynamic Modification of Palladium Catalysts with Chain Alkylamines for the Selective Hydrogenation of Alkynes

Selective hydrogenation of alkynes plays a pivotal role in the field of chemical production but still suffers from restrained catalytic activity and low alkene selectivity. Herein, a dynamic modification strategy was utilized by preferentially attaching diethylenetriamine (DETA) to the surface of the support to modify the Pd catalyst. The DETA-modified Pd catalyst demonstrates unprecedented reactivity (14,412 h(-1)) and selectivity as high as 94% for the semihydrogenation of 2-methyl-3-butyn-2-ol at 35 degrees C, presenting a 36-fold higher reactivity than the Lindlar catalyst. Moreover, the yield exceeds 98.2% at full conversion under no solvent and organic adsorbate conditions, indicating the potential applications for industrial production. Systematic studies reveal that flexible DETA serves in a reversible breathing pattern for the molecular discrimination by constructing dynamic metals-upport interaction (DMSI), enabling selective exclusion of alkenes from the Pd surface. DETA is competent to dynamically adjust the adsorption behaviors of reactants and effectively boost the intrinsic activity of the modified catalyst. Impressively, the DETA-modified Pd catalyst exhibits exceptional stability even after being recycled 20 times. This work sheds light on a novel and applicable method for the rational design of heterogeneous catalysts via DMSI.

Automated summary

Selective hydrogenation of alkynes is crucial in chemical production, but faces challenges such as low catalytic activity and alkene selectivity. A dynamic modification strategy involving DETA was used to enhance the reactivity and selectivity of the Pd catalyst, achieving unprecedented results. DETA plays a key role in adjusting the adsorption behaviors of reactants dynamically, leading to enhanced intrinsic activity of the catalyst.