Effect of Al2O3 doped on SO 2-/ZrO type solid superacid
Solid superacid SO 2-/ZrO (SZ) and SO 2-/ZrO -Al O (SZA) were prepared by the impregnation-deposition method.
Influence of WO3 doped on SO42-/ZrO2 type solid superacid.
This is because using 0.5 M (NH4)2SO4 is insufficient to provide necessary SO4 2-to form superacid; while using the high concentration (1.5 M), NH3 the decomposition product of NH4 is nucleophile inhibiting the formation of Bronsted acid sites.
Catalytic performance and reusability of composite solid superacid SZWA
The results show that the optimal conditions for preparation of composite solid superacid SZWA are as follows: the mass ratio of WO3/ZrO2 is 1 : 1, aging temperature is -10AoC, the mass ratio of Al2O3/ZrO2 is 3.5: 1, impregnation concentration is 1.0 M (NH4)2SO4 and the calcination temperature is 550AoC.
Since 1963 Olah and his coworkers have used superacid media, particularly [HSO.sub.3.F] - [SbF.sub.5], to obtain stable solutions of a wide variety of alkyl carbenium ions.
Other superacids that have been extensively studied include HF [8,9] for which [-H.sub.0] = 15 and [CF.sub.3.SO.sub.3.H] (trifluoromethane sulfonic acid commonly known as triflic acid) for which [-H.sub.0] = 14.1.
Superacids such as [HSO.sub.3.F] and [HSO.sub.3.F] - [SbF.sub.5] have been used to study the protonation of many weak bases.
Many other applications of superacids in organic chemistry have been described by Olah .
A very early application of the use of superacids in inorganic chemistry was the demonstration that the nitronium ion is formed in a solution of nitric acid in sulfuric acid 
A more recent interesting application of superacids has been the preparation of stable solutions and crystalline salts of a variety of novel cations of non metallic elements that are too highly electrophilic to be obtained in aqueous media.