One-Step Synthesis of Alkyltrimethylammonium-Intercalated Magadiite

Abstract

Abstraet--Cetyltrimethylammonium-and tetradecyltrimethylammonium-intercalated magadiites were prepared by direct syntheses, starting from sodium metasilieate (NaaO/SiO2 = 1.0) and nitric acid. Total substitution of sodium by cetyltrimethylammonium or tetradecyltrimetbylammoniurn cations was not achieved in the range of surfactant : silicon molar ratios used in this study. When a phosphoniun-based surfactant replaces the ammonium surfactants in the same procedure, the result of the synthesis is a mixture of quartz and unmodified surfactant. If dodecylammonium bromide is used, an MCM-41 molecular sieve is obtained. The substitution of the silicon source by tetramethylammonium silicate or of nitric acid by hydrochloric, hydrofluoric, or acetic acids also yields MCM-41 molecular sieves, indicating that the formation of magadiite is greatly dependent on the presence of sodium cations and nitrate anions.

Effect of thermal dehydration and rehydration on Na-magadiite structure

“…The Na-magadiite (Mag) was synthesized under highly alkaline conditions and sodium ions were present as expected in the claylike solid structure [23]. Under the basic conditions of silica gel under hydrothermal conditions at 150 • C, hydroxide ions have reacted with acid sites of silica producing water and leaving behind negative sites, which are counterbalanced by the sodium ions originally associated with the hydroxide ions.…”

Green and Cost-Effective Preparation of Small-Sized ZSM-5

“…The aggregates of the nano-sheets might be ascribed to Magadiite phase (Fig. 1d) 28 . The ZSM-5 exhibited conventional coffin-like morphology, with the crystal size of up to ~5 μm.…”

“…This leads to the slight decrease of the relative crystallinity (Table 1). It should be pointed out that when the active seeds were replaced by TPAOH (TPAOH/SiO2 ratio = 0.00175, which was equal to that when 0.5% of active seeds were used), impurity of obvious Magadiite phase could be observed for sample Z-TPA-120, leading to the further decreasing of the relative crystallinity 28 . This proved the effectiveness of the active seeds in directing to the synthesis of zeolite ZSM-5.…”

Synthetic, layered nanoparticles for polymeric nanocomposites (PNCs)

“…66 The new process was reported to be more economic. Structural diversity of MAG has been documented by Scholzen et al 67 The layered silicic acids (MAG, kenyaite, octosilicate/ ilerite and kanemite) have been also prepared hydrothermally with good control of platelets dimensions, 68 by means of templated preparations that led to organomodified materials, 69 using a one-pot method with structure directing agents, 70 or by using solid-state reactions. 71 Beneke et al also reported syntheses of layered lithium sodium silicate (silinaite).…”