A. Jimenezlopez et al., PILLARED CLAYS PREPARED FROM THE REACTION OF CHROMIUM ACETATE WITH MONTMORILLONITE, Clays and clay minerals, 41(3), 1993, pp. 328-334
Refluxing chromium (III) acetate with a Na+-montmorillonite suspension
gives rise to the intercalation of linear Cr(III) polyhydroxo-acetate
oligomers. Thermally stable chromia pillared montmorillonite material
s are obtained upon calcination under ammonia up to 625-degrees-C, and
basal expansions up to 6 angstrom are maintained. The porous material
s retain high surface areas (366-464 m2 g-1), a micropore volume of 0.
1 cm3 g-1 and narrow pore size distributions centered between 7.5 and
12 angstrom. The most thermally stable materials in air were those pre
pared under ammonia at 625-degrees-C, containing NH4+ as the exchangea
ble ion.