The surface area of kaolinite-benzamide (K-Bz) 6.62 m2 g−1, which is noticeably lower than that of kaolinite-dimethyl sulphoxide (K-DMSO) 14.61 m2 g−1, the co-perturbation of the inner-surface hydroxyl features at 3697 and 3650 cm−1, and the increase of d(001) value by 7.44 Å are all related to the benzamide species inserted into the kaolinite structure through the replacement of the K-DMSO composites. Disappearance of the DMSO reflections and emergence of well-defined features at 6.04(2θ) and 11.16(2θ), 001 and 002 reflections with d values of 14.62 and 7.92 Å, respectively point out that the DMSO species were substituted efficiently by benzamide molecules. The thermal stability of the K-Bz derivative up to 300°C can be attributed to the slightly tilted aromatic ring keying into the gibbsitic sheets via the –NH2 groups.
1 Lagaly, G1984Philos. Trans. R. Soc. LondonA 311315.