In order to synthesize pillared micas having larger basal spacing with controlled microporous properties, expandable Li-exchanged fluorine micas having different layer charges (x) [Li
xMg3
3-xLi
xSi
4O
10F
2(x=O.5, 0.8)] were allowed to react with various polynuclear hydroxochromium (III) ion solutions having different OH/Cr ratios at different temperatures, and the effects of reaction temperature on formation and properties of chromia pillared fluorine micas were studied. When intercalation was carried out above 80°Cusing solution of OH/Cr = 2.0, more highly polymerized Cr (III) -species were intercalated, compared with the case of intercalation at room temperature. The cation selectivity caused by layer charge of host mica crystals changed with reaction temperature; this resulted in larger amount [2.01mol (Si
4O
10)
-1] of intercalation of highly polymerized Cr (III)-species above 80°C even when layer charge of host crystals was large (x= 0.8). Consequently, pillared micas intercalated above 80°C showed more expanded basal spacings than those intercalated at room temperature. Pillared micas having larger layer charge (0.8) also kept larger basal spacings than those having smaller layer charge (0.5) when heated at 400-700°C, showing basal spacings of 1.1-1.4 nm. Moreover, pillared micas obtained by the reaction above 80°C showed larger specific surface area than those obtained at room temperature in the heating temperature range of 200-300°C.
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