Highly selective self-condensation of cyclohexanone: the distinct catalytic behaviour of HRF5015

HRF5015, a perfluorosulfonic acid resin catalyst with unique pore structures, was investigated in the catalytic self-condensation of cyclohexanone under mild conditions. The morphology of HRF5015 was characterized by transmission electron microscopy (TEM) and atomic force microscope (AFM), and the reaction mechanism was studied by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The effects of reaction time and temperature on the yield of dimer were investigated under the nitrogen atmosphere. The results show that the reaction temperature is low, and especially, the selectivity of the dimer is close to 100%. The apparent activation energy for the dimer formation reaction is 54 kJ mol(−1). Synergistic action of cluster structure formed by sulfonic groups and nanopores in HRF5015 may be the key factor of high-efficiency catalytic activity and high selectivity. In situ infrared spectra indicate that the intermediate is stable in the reaction process. HRF5015 is environmentally friendly and re-usable, which shows good potential in a future application.