Enhanced activity over alkyl/aryl functionalized porous pillared-zirconium phosphates in liquid-phase reaction

• Alkyl/aryl functionalized porous pillared phosphate has been synthesized.
• Enhanced activities were observed over these hybrid materials.
• The improvement in activity is due to the increase in surface hydrophobicity.
• The accessible acid sites play an important role in liquid-phase reactions.

A series of porous pillared-zirconium phosphates functionalized with methyl, ethyl, propyl and phenyl groups were prepared and characterized by SEM, 29Si MAS NMR, TG and N2 adsorption. Their total surface acidity and accessible one were measured by potentiometric titration of n-butylamine and liquid phase 2,6-di-tert-butyl-pyridine adsorption, respectively. The catalytic behaviors of these hybrid materials for alkylation of hydroquinone and esterification of lauric acid were compared. Not the total acid sites but the accessible ones play a crucial role in both reactions of alkylation and esterification. The accession for acid sites can be enhanced by the introduction of alkyl/aryl groups, due to the improved hydrophobicity of the surface.

Figure optionsDownload high-quality image (102 K)Download as PowerPoint slide