Phosphate-ZrO2-Si2O catalysts were synthesized by sol-gel method using trib
utyl phosphite, zirconium propoxide, and tetraethyl orthosilicate as precur
sors. They were characterized by N-2 adsorption, P-31 CP MAS NMR, and DRIFT
S. At lower P content, monomeric phosphates were formed on the surface of t
he catalysts, which were mainly responsible for the isopropanol dehydration
activity. At higher P content, polyphosphates were formed, and thus, the d
ehydration activity decreased. An optimum P content for dehydration activit
y was found to be at 10 mol%.