Functionalization of Mesoporous Carbon with Superbasic MgO Nanoparticles for the Efficient Synthesis of Sulfinamides

Highly basic MgO nanoparti- cles with different sizes have been suc- cessfully immobilized over mesoporous carbon with different pore diameters by a simple wet-impregnation method. The prepared catalysts have been char- acterized by various sophisticated tech- niques, such as XRD, nitrogen adsorp- tion, electron energy loss spectroscopy, high-resolution TEM, X-ray photoelec- tron spectroscopy, and the tempera- ture-programmed desorption of CO2. XRD results reveal that the mesostruc- ture of the support is retained even after the huge loading of MgO nano- particles inside the mesochannels of the support. It is also demonstrated that the particle size and dispersion of the MgO nanoparticles on the support can be finely controlled by the simple adjustment of the textural parameters of the supports. Among the support materials studied, mesoporous carbon with the largest pore diameter and large pore volume offered highly crys- talline small-size cubic-phase MgO nanoparticles with a high dispersion. The basicity of the MgO-supported mesoporous carbons can also be con- trolled by simply changing the loading of the MgO and the pore diameter of the support. These materials have been employed as heterogeneous catalysts for the first time in the selective syn- thesis of sulfinamides. Among the cata- lysts investigated, the support with the large pore diameter and high loading of MgO showed the highest activity with an excellent yield of sulfinamides. The catalyst also showed much higher activity than the pristine MgO nano- particles. The effects of the reaction pa- rameters, including the solvents and re- action temperature, and textural pa- rameters of the supports in the activity of the catalyst have also been demon- strated. Most importantly, the catalyst was found to be highly stable, showing excellent activity even after the third cycle of reaction.