Acid Sites in Sulfated and Metal-Promoted Zirconium Dioxide Catalysts

One‐Step Preparation of Efficient and Reusable SO42−/ZrO2‐Based Hybrid Solid Catalysts Functionalized by Alkyl‐Bridged Organosilica Moieties for Biodiesel Production

“…[9,31] Second, the acid capacity of the tested catalysts was measured by titration with diluted KOH, and was expressed by the number of equivalents of H + in the catalysts (A titration , Tables 1 and 2). [32][33][34] From the results summarized in Table 1, it is found that SO 4 2À /ZrO 2 exhibits a high acid capacity of 1070 meq g À1 (entry 1 in Table 1).…”

Acidity-Reactivity Relationships in Catalytic Esterification over Ammonium Sulfate-Derived Sulfated Zirconia

“…A suspension of the parent zirconia is moderately acidic (pH = 4.68). Sulfation for loadings 1.7 wt % increased the acidity (pH = 2.82); however, additional surface sulfate did not further increase acidity (pH = 2.96), indicating that the strongest acid sites were associated with surface bisulfate species just prior to saturation of the monolayer [38,39], with pyrosulfate (species III) formed at higher loadings possessing slightly weaker acidity. N-propylamine has been described by Gorte and co-workers as a probe for Brønsted acidity [36]; however, n-PA adsorption on Lewis acid sites is also reported [40].…”

Investigation of factors influencing catalytic activity for n-butane isomerization in the presence of hydrogen on Al-promoted sulfated zirconia

“…When some promoters such as Fe, Mn, Ni and Cr were introduced into sulfated zirconia [12][13][14][15][16][17], it was found that these promoters significantly increased catalytic activity on n-butane isomerization at low temperature. However, rapid deactivation was still observed [18][19][20] and the marked promoting effect disappeared if the reaction was performed at high temperature (523 K) in the presence of hydrogen [21,22].…”