Fabrication and Reinforcement of Macro- and Mesoporous Bimodal Materials from Mesoporous Silica-Alumina Spheres and Their Applications to Acid Catalysts and Adsorbents

Abstract

Mesoporous silica-alumina spheres were used to create macro- and mesoporous bimodal silica-aluminas. Before removing the surfactant template for mesopores, the silica-alumina spheres were neatly stacked by sedimentation, and the contact points between the spheres were reinforced by silica. The bimodal silica-alumina was used as an acid catalyst for transesterification of triglyceride with methanol. The bimodal catalyst was readily separated from the reaction mixture. It showed the same catalytic activity as the non-sedimented spheres and higher activity than the catalyst prepared by pelletizing the silica-alumina spheres with colloidal silica binders. The bimodal materials were utilized as an adsorbent with an indicator of adsorption amount since the color changed with the amount of toluene that was adsorbed on them.