Aldol condensation reaction of acetone on MgO nanoparticles surface: An in-situ drift investigation

Acetone adsorption and catalytic interactions with a MgO nanoparticle surface was studied using in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) at room temperature. Acetone showed adsorption bands at 2965, 1717, 1597, 1422, 1415, 1367, 1238, 1229, and 1204 cm(-1). The MgO was found to be a good catalyst for the activation of the aldol condensation reaction of acetone to form di-acetonealcohol (DAA). The OH group role on the MgO surface was found to be a suppression agent to the further dehydration of DAA to mesityl oxide. This is probably because the OH group blocks the active sites on the MgO surfaces that adsorbed the water formed from the dehydration of DAA. This conclusion was confirmed by identifying the basic site concentrations on MgO surface using DRIFTS and TPD studies of CO2 adsorption/desorption on MgO nanoparticles surface. The high-strength basic sites which are required to dehydrate DDA to mesityl oxide was found to represent only 17.5 % of the total basic site concentration, while the low-strength basic sites resulted from hydroxyl surface group represent 22.5 %. On the other hand, the acetone interaction with the MgO surfaces produced several components such as formaldehyde, acetate, ethoxide, as well as other carbonate species such as bicarbonate, bidentate carbonate, and monodentate carbonate. The results of the present investigation supply important essential insights into catalytic reactions resulted from acetone adsorption on MgO nanoparticle surfaces.