Immersion Microcalorimetry and13C CP/MAS NMR Study of the Structure of Organoclays

✍ Scribed by K. Khatib; M. Francois; P. Tekely; L.J. Michot; J.Y. Bottero; I. Baudin

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 124 KB
• Volume: 183
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1996.0529

✦ Synopsis

presence of a cosolvent such as methanol increases the reten-The organoclays as dimethyldistearyl ammonium montmoriltion of micropollutants like atrazine (9). Methanol helps in lonite (DDA-Mt) are interstratified clays in which pure organic the penetration of the pollutant by modifying the material's sheets and silicate layers coexist. The stacking disorder depends texture. Recently it has been shown that in the presence of on the conformation of the DDA within the interlayer. This conforwater or methanol vapor, or liquid methanol, the interlayer mation depends on the quantity of sorbed vapor methanol. Immerdistance remains the same but the stacking order of the sheets sion microcalorimetry of DDA-Mt in liquid methanol data shows increases and the material behaves as an ordered system endothermic reactions. The CH 2 /CH 2 bonds between two adjacent . The structure of the clay particles, formed with alkyl chains are disrupted at P/P 0 õ 0.6 corresponding to two turbostratic stacking of the sheets, is closely related to the methanol molecules for one polar head. Beyond this value DH is constant. 13 C CP/MAS NMR data show, by correlation, that the structure of the organic phase in the interlayer space. The mobility of the chains is strongly increased at P/P 0 ú 0.6. Mobility CH 2 groups in short-chain (tetramethylammonium) and and distance between alkyl chains vary in the same direction and long-chain (hexadecylammonium) surfactants have a high correspond to an increase in the stacking order of the sheets within local mobility as revealed by 13 C cross-polarization/magica particle.