Preparation of Alumina Pillared Montmorillonite Clays Employing
Ultrasonics and Their Catalytic Properties
Suhas P. Katdare, Veda Ramaswamy and A.V. Ramaswamy
Catalysis & Inorganic Chemistry Division National Chemical Laboratory, Pune-411 008, India
An accelerated diffusion of alumina precursor species in-between the gallery region of montmorillonite
clays by the use of ultrasonic technique is described. This method offers a faster, efficient and attractive route for the synthesis of alumina-pillared clay catalysts. Out of the several preparative parameters studied, the role of pre-exchanged cations influenced the optimum duration of ultrasonic agitation and treatment for the pillaring process. By comparing ultrasonic route and conventional preparation procedure, it is revealed that uniform spacing of alumina pillars in the clay means homogeneously distributed acid centers. The influence of calcination temperature on the acidity and hence the catalytic activity is described. The choice of three different montmorillonite clays with different cation exchange capacities enables one to tune the pore dimensions of the pillared clays. The catalytic applications include studies on cumene cracking, dehydration of propan-2-ol and alkylation of benzene with linear olefins.