Mechanochemical synthesis of the [Al_(13)O4(OH)_(24)(H2O)_(12)]~(7+) Keggin ion

摘要

In this study, we demonstrate the synthesis of the [Al_(13)O4(OH)_(24)(H2O)_(12)]~(7+) Keggin ε-Al_(13) ion by a mechanochemical reaction between [Al(H2O)6]Cl3 and (NH4)2CO3 reactants. Five grams of the starting mixture corresponding to a molar ratio of (NH4)2CO3/[Al(H2O)6]Cl3 = 0.45:2,1:2,1.5:2,2:2,2.25:2,2.55:2 and 3:2 was milled for 5 min. The existence of ε-Al_(13) was observed at molar ratios of (NH4)2CO3/ [Al(H2O)6]Cl3 = 2:2 and higher. Our results show that more than 50% mass of Al from a starting [Al(H2O)5]Cl3 was bonded to the polymeric [Al_(13)O4(OH)_(24)(H2O)_(12)]~(7+) ionic form at a molar ratio of 2.55:2.