Surface Acidity, Acid Strength Distribution and Catalytic Activity of some Binary Metal Oxides Based on Alumina

Department of Chemistry, Central College, Bangalore University, Bangalore 560001 Manuscript received 7 September 1972; revised 22 January 1973; accepted 7 May 1973 Surface acidity and acid strength distribution on the surface of metal oxides based on alumina has been measured. It is observed that the acidities and acid strengths decrease in the followlag order : Al2O3-MoO3 > Al2O3-WO3 > Al2O3-V2O2 > Al2O3-MgO > Al2O3-BeO > Al2O3-ThO2. Al2O3-MoO3 has on its surface an acid strength equivalent to Ho = —5.6, where as other mixed oxides have on their surfaces an caid strength equivalent as follows, A.1203-WO3 and Al2O3-V2O5 have Ho = —3.0, Al2O3-MgO and Al203-BeO have Ho = +3.3 and Al2O3-ThO2 has Ho = +4.8. A study of the depolymerisation of paraldehyde by these catalysts indicates that only those catalysts having an acid strength equivalent to H0 = —3.0 are able to catalyse the depolymerisa­tion of paraldehyde