Sodium montmorillonite (Na+-MMT) organically modified with regioselectively synthesized (ω-1)- morpholinododecanoic acid: preparation and characterization

In this study, an organically modified sodium montmorillonite (Na+-MMT) was prepared by intercalation with a regioselectively synthesized (ω-1)-morpholinododecanoic acid. Regioselective synthesis of the organic modifier involved the preliminary preparation of (ω-1)-chlorododecanoic acid and its subsequent amination with morpholine. The synthesized aminated product was then intercalated into the interlayer spacing of montmorillonite via a cation exchange reaction. Gas chromatography (GC) results showed that 98.40% of the product was chlorinated dodecanoic acid, 45.66% of which indicates chlorination at the ω-1 position. Seventy two (72)-hour amination led to the production of 58.80% morpholinated dodecanoic, with 39.64% of the morpholino moiety positioned at ω-1. Characterization of the aminated product by infrared (IR) spectroscopy revealed the presence of C-N and C-O stretches at 116.78 cm -1 and 1240.23 cm-1, respectively, indicating successful synthesis of the morpholinated product. IR spectra of the (ω-1)-morpholinolauric acid modified montmorillonite (MLA-MMT) not only showed characteristic bands belonging to MMT but also several new absorption bands belonging to (ω-1)- morpholinolauric acid such as the aliphatic stretches at 2929.87 cm -1 and 2858.51 cm-1, C-O-C stretch at 1539.20 cm-1, and C-N stretch at 1624.06 cm-1. The presence of new peaks both for MLA-MMT indicated strong interaction of the organic modifier and the clay interlayer implying successful intercalation. X-ray diffraction (XRD) patterns of Na+-MMT and MLA-MMT showed reflection peaks at 20 = 7.0 degree and 20 = 6.5 degree, resulting to increased basal spacings from 1.31 nm to 1.38 nm. This increase in the interlayer spacing of montmorillonite proved the the organically modified clay has been successfully prepared. (author)