SYNTHESIS, CHARACTERIZATION AND ACID-BASE PROPERTIES OF LAYERED DOUBLE HYDROXIDES PILLARED WITH TUNGSTOSILICATE ANIONS

Layered double hydroxides (LDHs) pillared with heteropolyanions, SiW(1 1)M . (H2O)O-39(6-) (M is the first row transition metals), were synth esized by means of direct ion-exchange reaction and were characterized by elementary analysis, XRD, IR and DTA. The results show that the in terlayer space of the pillared products increase from 0. 92 nm to 1. 4 7 nm, and there is an increase in the thermal stability of the pillare d product with the heteropolyanion intercalating into the LDH. The pil lared products shows the acid-base bifunctional catalysis over the iso propanol conversion, and the acidity is relatively stronger.