1. Two different types of framework-substituted aluminophosphate catalysts were prepared and their catalytic potential was evaluated in the selective oxidation of cyclohexane at 100 C using O2 as oxidant. Catalyst A was synthesised using cobalt (II) acetate as the metal precursor whilst silica was employed as the metal precursor for the synthesis of Catalyst B. The structure-directing agent (methyl dicyclohexyl amine) was removed, in both cases, by calcination in O2 at 550 C, which resulted in the generation of a three-dimensional channel having the AFI topology.

(i) Outline and sketch the type of substitution mechanisms that could be facilitated in the design of these catalysts and describe the nature of the active sites.

(ii) Sketch the type of oxidation products that are likely to be generated at the frameworkactive sites in catalysts A and B post-calcination and highlight the nature of the active site with respect to the substitution mechanism.