STUDY ON THERMAL-PROPERTY OF HETEROPOLYAC IDS WITH KEGGIN STRUCTURE

In this paper, the thermal stability of heteropolyacids with Keggin st ructure H(n)XM(12)O(40) (X = Si, P, Ge; M = Mo, W) were studied system atically by DSC, TG-DAT, X-ray diffraction, IR spectra at various temp eratures and solubility experimental methods. The new criterion of the rmal decomposition for heteropoly compounds was proposed. The mechanis m of thermal decomposition for heteropolyacids with Keggin structure w as presented. A semi-empirical equation being used to predict the ther mal decomposition temperatures was obtained. The reaction order and ac tivation energy in every step of loss weight was calculated.