Microencapsulation of STA to Retain Its Catalytic Activity

Silicotungstic acid (STA) is microencapsulated in a silica shell to retain its activity during repeated use as a catalyst. A modified synthesis procedure of sol-gel microencapsulation is used. The encapsulated catalyst is characterized using SEM for morphology and FTIR  and INAA for elemental composition.  The surface area, pore size and distribution of the catalyst is determined by BET. The activity of the catalyst is tested in a variety of reactions such as an esterification reaction. The catalyst used is washed, dried and re-used in repeated runs to determine the activity of the catalyst in repeated runs The amount of leaching of the active material from the catalyst structure after repeated use in the reactions is also determined.   Results obtained will be presented.