MCM-41 supported H~3PW~1~2O~4~0(PW) catalysts were prepared and characterized. PW crystal phase was not observed in X-ray diffraction patterns at PWloading as high as 70%(quality fraction). The chemical interation between PW and the support was stronger on MCM-41 than on amorphous SiO~2. The acid sites in bulk PW were uniform and strong with differential heat of NH~3 adsorption in the range of 160- 180kJ/mol, whereas in PW/MCM-41 catalysts the acid sites became less uniform and weaker due to the strong interaction between PW and the support. The quantity and distribution of acid sites in PW/MCM-41 catalysts could be adjusted by varying PW loading. The catalytic activities of PW/MCM-41 catalysts toward acid-catalyzed reaction requiring different acid strengths were tested, and the results showed that they were promising catalysts for medium strong and weak acid-catalyzed reactions.

Key words: PHORSPHORIC ACID, TUNGSTIC ACID, HETEROPOLYACID, MOLECULAR SIEVE, CATALYTIC ACTIVITY, X-RAY DIFFRACTION ANALYSIS