Revisión de la influencia de la modificación de la hidrofobicidad de las silicalitas de titanio sobre su actividad catalítica (Influence of the hydrophobic modification of titanosilicates on their catalytic activity: A review).

Abstract

: Titanosilicates are catalysts which have been successfully used in selective oxidation reactions whereby, some alternatives have been developed to enhance their activity. One of these is the modification of x x the hydrophobicity of the catalyst surface. The hydrophobicity of these materials plays an important role on the adsorption/desorption processes and consequently, on the catalytic performance. Several researchers have studied the hydrophobization of titanosilicates, but the effect on their catalytic activity has not been reviewed yet. In addition, the methodologies to measure the hydrophobicity differ in each work making difficult the comparison of this property. For this reason, in this work crystalline and amorphous titanosilicates that have been modified hydrophobically were addressed. A comparison and discussion of the methodologies for hydrophobic modification, the analytical techniques for characterization of hydrophobicity, and the effect of hydrophobization on their catalytic activity were performed. A significant improvement of hydrophobicity characterization has been reached as a result of the combination of two or more analytical techniques. However, the improved catalytic activity cannot be totally attributed to the hydrophobic modification due to the complexity of the reaction systems, interactions between catalyst surface and liquid medium. Thus, more extensive studies including kinetic, thermodynamic, spectroscopy, and computational analysis are required to gain more understanding of the effect of hydrophobizing the surface of titanosilicates and other porous solid catalysts.