CHARACTERIZATION AND ACTIVITY OF PRASEODYMIUM OXIDE CATALYSTS PREPARED IN DIFFERENT GASES FROM PRASEODYMIUM OXALATE HYDRATE - MICROSCOPIC, THERMOGRAVIMETRIC AND IR SPECTROSCOPIC STUDIES
Gam. Hussein, CHARACTERIZATION AND ACTIVITY OF PRASEODYMIUM OXIDE CATALYSTS PREPARED IN DIFFERENT GASES FROM PRASEODYMIUM OXALATE HYDRATE - MICROSCOPIC, THERMOGRAVIMETRIC AND IR SPECTROSCOPIC STUDIES, Journal of the Chemical Society. Faraday transactions, 91(9), 1995, pp. 1385-1390
Citations number
27
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
PrO1.833 and Pr2O3 catalysts have been obtained as final decomposition
products of Pr-2 (C2O4)(3) . 10H(2)O in different gases (O-2, N-2, an
d H-2). The decomposition processes were characterized by thermogravim
etric (TG) and differential thermal analysis (DTA), X-ray diffraction
(XRD) and IR spectroscopy of the solid-phase products. The results ind
icate that the compound dehydrates in three steps at 100, 150 and 380
degrees C and that the anhydrous oxalate decomposes at 445 degrees C t
o form two phases of Pr2O2(CO3) depending upon the atmosphere used for
the reaction. On further heating PrO1.833 is formed at 550 degrees C
in O-2 and at 650 degrees C in N-2. In contrast, Pr2O3 was formed at 6
50 degrees C in H-2. Surface area measurements and scanning electron m
icroscopy (SEM) have shown that PrO1.833 produced at 700 degrees C has
a different surface area depending on the gas used: 43 and 64 m(2) g(
-1) for O-2 and N-2, respectively. The surface area of Pr2O3 formed in
H-2 is 59 m(2) g(-1). The texture of the catalyst has been found to d
epend upon the decomposition atmosphere. IR spectroscopy has been used
to analyse (qualitatively and quantitatively) the gas-phase reaction
products between room temperature and 400 degrees C from the dehydroge
nation and dehydration reactions of propan-2-ol over PrO1.833 and Pr2O
3, catalysts. The results revealed that Pr2O3 is a selective dehydrati
on catalyst at 275 degrees C, decomposing propan-2-ol into propene (ca
. 80%). However, PrO1.833 is a dual function dehydration/dehydrogenati
on catalyst.