Solvent effect on synthesis of zirconia support for tungstated zirconia catalysts

Solvothermal reaction of zirconium n-butoxide (ZNB) in different solvent media, such as 1,3-pentanediol, 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol resulted in the formation of zirconium dioxide (ZrO2) nanostructure. Then, the 15%W/ZrO2 (WZ) catalysts using different zirconia supports were prepared by impregnation method. The effects of solvent on preparation of zirconia on the catalytic performance of WZ catalysts in esterification of acetic acid and methanol at 60 °C were investigated. The experimental results showed that ZrO2 particles prepared in 1,4-butanediol (ZrO2-BG) have a spherical shape, while in other glycols the samples were irregularly-shaped particles. The reaction results of esterification illustrated that the W/ZrO2-BG catalysts had high surface acidity and showed high acetic acid conversion. The W/ZrO2-PeG catalysts (ZrO2 particles prepared in 1,5-pentanediol, PeG) exhibited the lowest surface acidity among other samples due to strong interaction of proton species and the zirconia supports as proven by TGA. One of the possible reasons can be attributed to different amounts of carbon residue on the surface of catalysts.