Exploration on the Unusually Strong Basic Properties of KNO₃/Al₂O₃ and K₂CO₃/Al₂O₃

Dispersions of KNO₃ or K₂CO₃ loaded on Al₂O₃ was examined by means of XRD and XPS,while the basic properties of these unusually strong solid bases,derived from the Al₂O₃ supported KNO₃ or K₂CO₃,were evaluated by use of CO₂-TPD,titration and the isomerization of butene at 0℃.
If the amount of KNO₃ or K₂CO₃ loaded is below its monolayer dispersion threshold on Al₂O₃,all of them can be well disersed and consequently a basic strength (H^-) of 18.4 is produced.When the amount loaded is above the threshold,however,a lot of KNO₃ seems to locate in the pore of Al₂O₃ and a new phase such as K₂ Al (NO₃)₅ is formed.Evacuation at 600℃ caused not only the decomposition of residual KNO₃ and K₂ Al (NO₃)₅, but also the migration of potassium species from the inner to the external surface of Al₂O₃.As a result,sever layers of basic species such as K₂O may overlap on the Al₂O₃,because the KNO₃ dispersed and decomposed has exceeded the monolayer threshold.It is important to find that some superbasic sites iwth a basic strength (H^-) of 27.0 are formed on both 20%K₂CO₃/Al₂O₃ and 29%KNO₃/Al₂O₃ smples.Based on the advantages in preparation and storage,these new unusual strong solid bases are expected to be used as the nwe basic catalysts in industrial.