Unusual Intercalation of Cationic Smectite Clays with Detergent‐Ranged Carboxylic Ions

Abstract

Abstract Summary: The organic intercalation of cationic smectite clays is achieved by using alkali salts of alkyl carboxylic acids, instead of using conventional quaternary ammonium salts as ionic exchanging agents. Various organic acid salts, such as CH 3 (CH 2 ) 16 COO − Na + , can be incorporated into divalent montmorillonite (M 2+ ‐MMT) with a 30–40 wt.‐% organic embedding and an X‐ray diffraction basal spacing of 43 Å from the pristine 10 Å. The intercalation is generalized for carboxylate salts of different alkyl lengths and for alkali metal ions, including sodium and potassium ions, but is specific for the divalent MMT clay. This new type of organic species for clay modification allows the preparation of organoclays in the absence of quaternary ammonium salts. It is proposed that the organic embedding is driven by the formation of a thermodynamically stable RCOO − /M 2+ /SiO − complex. Graphical illustration of the carboxylic acid salt complex with the divalent cations on silicate K10. magnified image Graphical illustration of the carboxylic acid salt complex with the divalent cations on silicate K10.