Grafted organic derivatives of kaolinite: II. Intercalation of primary n-alkylamines and delamination

Abstract

Kaolinite was intercalated with n-hexylamine, n-octadecylamine and n-docosanamine, using methanol-kaolinite as the precursor. The intercalation compound with n-docosanamine presented the largest basal spacing for a kaolinite derivative thus far reported (64.2 Å). Five grafted derivatives of kaolinite were directly intercalated with n-hexyl- and n-octadecylamine. During intercalation, the grafted molecules rearrange from parallel to perpendicular orientation to the kaolinite surface, in order to maximize the interaction with the amine and minimize the interlayer expansion needed. The octadecylamine intercalation compounds were delaminated in toluene, accompanied by the deintercalation of the amine molecules. Thin kaolinite particles rolled into a halloysite-like morphology, but forming much smaller tubes, some of which possibly consist of single kaolinite layers. The delamination was more efficient with the grafted kaolinites than with raw kaolinite.

From platy kaolinite to aluminosilicate nanoroll via one-step delamination of kaolinite: Effect of the temperature of intercalation

“…Some efforts have been made to synthesize high-quality halloysitelike nanotubes during the last decades (Gardolinski and Lagaly, 2005;Kuroda et al, 2011). As high-quality kaolinite is readily available at low cost, one of the most attractive methods for synthesizing aluminosilicate nanotubes is based on the delamination and rolling of kaolinite layers.…”

“…Subsequently, Singh and Mackinnon (1996) experimentally demonstrated the formation of halloysite-like nanosized tubes through the use of repeated intercalation and deintercalation of kaolinite using potassium acetate. Gardolinski and Lagaly (2005) proposed a method for the transformation from platy kaolinite to halloysite-like nanotubes with high transformation efficiency. Kaolinite was first interlayer-grafted with alkanols, diols, and glycol mono-ethers and intercalated with n-alkylamines; the obtained intercalation compound was then delaminated in toluene, which was accompanied by the deintercalation of the amine molecules.…”

Characterization of Aluminum(III) Complexes in Coal Organic Matter

“…It seems that these compounds can originate from a gibbsite layer in kaolinite, which occurs frequently in coal and lignite. It is well known that an outstanding property of dispersed kaolinite particles is delamination into individual silicate and gibbsite layers [61] [62]. This delamination to octahedral gibbsite and tetrahedral silicate layers preceded the formation of the Al complexes.…”

Effect of Intercalation Agents on Morphology of Exfoliated Kaolinite

“…As an intermediate to further intercalate large guest species, methoxy-modified kaolinite has been paid great attention to [15,[22][23][24][25]. So far, the intercalation of kaolinite by inserting series alkylamines [15,22,26], series quaternary ammonium salts [23,27], series silanes with an amino group, benzyl alkyl ammonium chlorides [28,29], series fatty acids and salts [30,31] into kaolinite layers by taking a methanol-grafted kaolinite compound as a precursor has been successfully performed. When n-docosanamine was intercalated into kaolinite, the basal spacing of the corresponding intercalation compound was the largest, increasing up to 6.42 nm [26].…”

“…So far, the intercalation of kaolinite by inserting series alkylamines [15,22,26], series quaternary ammonium salts [23,27], series silanes with an amino group, benzyl alkyl ammonium chlorides [28,29], series fatty acids and salts [30,31] into kaolinite layers by taking a methanol-grafted kaolinite compound as a precursor has been successfully performed. When n-docosanamine was intercalated into kaolinite, the basal spacing of the corresponding intercalation compound was the largest, increasing up to 6.42 nm [26]. It is widely accepted that remarkable interfacial adhesion, such as hydrogen bonds, van der Waals forces and dipole-dipole interactions, impedes kaolinite lamella exfoliation.…”