Reactivity of the Ruddlesden−Popper Phase H₂La₂Ti₃O₁₀ with Organic Compounds: Intercalation and Grafting Reactions

Abstract

A protonated form of the Ruddlesden−Popper-type ion-exchangeable layered perovskite H2La2Ti3O10 (H2LaTi) has been modified with n-alkylamine and n-alcohols to yield intercalation compounds and alkoxy derivatives, respectively. As concerns the intercalation of n-alkylamines into H2LaTi, no reaction of H2LaTi with n-butylamine occurred in anhydrous solvent, and the addition of water was required for the successful intercalation of n-butylamine into H2LaTi. The successful uptake of n-butylammonium ions from an n-butylammonium hydroxide aqueous solution suggests that the intercalation mechanism is of the ion-exchange type rather than the acid−base type. For interlayer surface modification with n-alcohol, no direct reaction of H2LaTi with n-alcohol occurred, but the n-propoxy derivative of H2LaTi formed by using the intercalation compound of H2LaTi with n-butylamine as an intermediate. In addition, reactions between the n-propoxy derivative of H2LaTi and n-alcohols (n-butanol, n-octanol, n-decanol, and n-dodecanol) led to the formation of various n-alkoxy derivatives via an alcohol-exchange-type reaction. As the model for n-alkoxy derivatives of H2LaTi, a bilayer arrangement of the n-alkyl chain possessing an all-trans ordered state with a 75° tilting angle is proposed. The reaction mechanisms of these reactions are also discussed.