Intercalation of benzamide into kaolinite

Well-crystallized kaolinite (K) was initially reacted at 60 degrees C with a water/dimethylsulfoxide (DMSO) mixture and the resulting intercalation de rivative (K-DMSO) was characterized by powder X-ray diffractometry (PXRD), thermal analysis (simultaneous TG and DSC), and Fourier-transformed infrare d spectroscopy (FTIR), Benzamide crystals were then melted with the K-DMSO derivative at 140 degrees C for 4 days, when a gradual displacement of DMSO by benzamide was observed within the interlayer spacing of the modified ka olinite. The resulting material, after extensive washing with acetone, was characterized and compared to the results obtained previously for the K-DMS O composite. Benzamide intercalation proceeded by gradual displacement of D MSO molecules until completion. The structural stabilization of the K-BZ de rivative was explained through the establishment of hydrogen bonds between the carbonyl oxygen atoms of the intercalated benzamide and aluminol groups present at the surface of the kaolinite layer. The interlamellar spacing o f K-BZ was shown to be possibly occupied by benzamide molecules that were l ocated at a 68 degrees orientation in relation to the layer surface. Unlike most intercalation molecules such as DMSO, variations in the interplanar s pacing of kaolinite were consistent with the nonkeying of any other part of the molecule between the aluminosilicate interlayers. (C) 2000 Academic Pr ess.