Selective anion-exchange intercalation of isomeric benzoate anions into the layered double hydroxide [LiAl2(OH)6]Cl·H2O

✍ Scribed by Lixu Lei; Aamir Khan; Dermot O’Hare

• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 226 KB
• Volume: 178
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2005.09.012

✦ Synopsis

All the geometric isomers of the benzoate derivatives, XC 6 H 4 CO 2 À (X ¼ F, Cl, Br, OH, OCH 3 , NO 2 , CO 2 CH 3 , NH 2 , N(CH 3 ) 2 ) can be intercalated into the layered double hydroxide [LiAl 2 (OH) 6 ]Cl Á H 2 O in 50% (v/v) water/ethanol solution at 80 1C to give fully anionexchanged first stage intercalation compounds [LiAl 2 (OH) 6 ]G Á yH 2 O (G ¼ a substituted benzoate). The observed interlayer separations of the intercalates vary from 14.3 A ˚for [LiAl 2

Competitive intercalation studies using mixtures of isomeric benzoates showed that the 4-isomers and 2-isomers are the most and the least preferred anions, respectively. Comparing the calculated dipole moments of the anions with the observed isomeric intercalation preferences suggests that dipole moment may be a good general index for the preference; however, it should be remembered that the bulkiness and electronegativity of the other substituent could be very important factors that affect the preferential intercalation.