Fig xA XRD pattern of the

To intercalate large-size guest molecules into kaolinite, the intercalation UM 171 of kaolinite/methanol (KM) was confirmed as a highly efficient intermediate [1] and [4]. The intercalation ratio (I.R.) of KM is a key factor influencing the displacement intercalation. The reported methods to prepare KM have the disadvantages of long reaction times and low I.R., although some precursors, such as the intercalation compound of kaolinite/DMSO (KD), were used. For example, the (001) diffraction peak of kaolinite is detected clearly for the reaction time of 5–7 days [1], [5], [6] and [7]. From the I.R. point of view, the I.R. of KM is relative low even using the PTFE-lined autoclave and intercalating at high reaction temperature and long time of 200–270 °C and 89 h [8].
Using KM as an intermediate, Gardolinski and Lagaly achieved nanotubes with relative high yield by a cycle of intercalation and deintercalation of alkylamines [9]. Kaolinite nanotubes were fabricated by Kuroda et al. using N-Hexadecyl trimethyl ammonium chloride (CTAC) as a guest molecule [10]. Moreover, the structural order of kaolinite has an important effect on the formation of nanotubes [11] and [12]. The yield of nanotubes is significantly increased in high structural ordered kaolinite. The increasement of yield is mainly contributed by the grafting reaction with methanol and the subsequent reaction with long-chain octadecylamine [12]. However, all these processes mentioned above are extremely time-consuming in steps of stirring, intercalation/deintercalation and rolling.