Preparation of silicotungstenic acid-containing mesoporous materials.

Silicotungstenic acid (STA)-containing mesoporous materials were directly synthesized in a nonaqueous medium by sol-gel method. X-ray powder diffraction showed that both as-synthesized and calcined materials possess mesoporous structure. STA contents in extraction solutions were analyzed with inductively coupled plasma. When STA/silica ratio changed from 1:100 to 1:4, the immobilization of STA is lower than 70%. However, when the STA/silica ratio reached 1:1 or higher, STA species was totally incorporated with surface area greater than 80 square meter per gram.