Unlocking ketone dimerization efficiency with multifunctional Zr and Hf based UiO-66 and NUS-6 MOFs: A synergy of experiment and theory

Heterogeneous catalysis is highly desirable for the self-condensation of cyclohexanone, an important step in producing intermediates for fine chemicals and polymers. Conventional methods often rely on toxic reagents and long reaction times, limiting their industrial viability. In this study, Zr- and Hf-based metal–organic frameworks (UiO-66 and NUS-6) were developed as efficient, environmentally friendly catalysts for the self-condensation of cyclohexanone. Their high surface area and hierarchical porosity, combined with bifunctional Brønsted and Lewis acid sites introduced through partial linker substitution, enable excellent catalytic performance. UiO-66(Zr) achieved 81 % conversion in 6 h and 98 % in 48 h, while NUS-6(Zr) reached 85 % and 86 % under the same conditions, with high selectivity toward the desired dimer products. The catalysts also showed strong thermal stability and reusability, maintaining activity at elevated temperatures. This work demonstrates a sustainable catalytic pathway for cyclohexanone dimerization, avoiding corrosive chemicals while offering both efficiency and selectivity.