Mesoporous carbon encapsulated with SrO nanoparticles for the transesterification of ethyl acetoacetate.

Highly basic active sites were introduced by the encapsulation of SrO nanoparticles inside the porous channels of highly ordered mesoporous carbon using wet-impregnation method. The samples prepared were thoroughly investigated employing various physico-chemical characterization techniques such as X-ray diffraction (XRD), N2 adsorption, high resolution transmission electron microscope (HRTEM) and elemental mapping. The basic sites located inside the nanochannels were quantified by the temperature programmed desorption (TPD) of CO2. XRD, N2 adsorption and HRTEM results revealed that the structural order of the parent CMK-3 support is retained even after higher loading of SrO nanoparticles. TPD of CO2 profiles confirmed that the number of basic active sites can be controlled by varying the SrO loading and the pore diameter of the CMK-3 support. The catalytic potential of the prepared samples was investigated on the transesterification of ethyl acetoacetate (EAA) as a probe reaction. Among the catalysts studied, CMK-3-150 loaded with 30 wt% of SrO nanoparticles exhibited the highest catalytic activity. The effect of various alcohols such as aryl (benzyl alcohol), aliphatic (1-butanol and 1-octanol) and cyclic alcohols (cyclohexanol and furfuryl alcohol) affecting the activity of the catalyst was also investigated. It was found that the catalyst offers maximum conversion when linear aliphatic alcohols especially, 1-butanol with shorter chain length are used. The amount of SrO loading, pore diameter of the CMK-3 support and the weight of the catalyst affecting the catalytic performance of the samples were investigated and discussed in accordance with the physico-chemical characterization data of the catalysts.