Achieving a Large Reactivity Activity Improvement in Adenine Modified Pd/Co-MOFs Catalyst for Quinoline Hydrogenation

The chemo-selective hydrogenation of quinoline is a critical reaction, producing high-value chemical intermediates such as pharmaceuticals, pesticides, and dyes. Traditional heterogeneous catalysts for this reaction typically require higher and more stringent reaction conditions due to the stable π-conjugated structure of quinoline. To achieve this transformation, some innovative strategies must be developed to enhance the catalytic properties of conventional catalysts. In this work, adenine was employed as a novel structural modifier to finish Co-MOFs materials and prepare Pd/Co-MOFs_(A) catalysts. The introduction of adenine efficiently enhanced structural stability and catalytic efficiency of original Pd/Co-MOFs catalyst. A remarkable increase of approximately 441% in catalytic conversion was obtained compared to the unmodified catalyst. This substantial improvement in catalytic performance could be attributed to mass transfer enhancement. The N-heterocyclic conjugated structure facilitated π–π stacking interactions and hydrogen bonding between the catalyst and quinoline, thereby accelerating mass transfer and improving catalytic efficiency. Under mild reaction conditions, the Pd/Co-MOFs_(A) catalyst fully demonstrated its high catalytic performance, achieving a 99.0% quinoline conversion and a 99.9% selectivity toward 1,2,3,4-tetrahydroquinoline. Finally, the Pd/Co-MOFs_(A) catalyst presented in this study could pave the way for enhancing the catalytic performance of traditional heterogeneous catalysts through alkaloid modification in quinoline hydrogenation.