Ionic Liquid assisted Synthesis of Zeolite-TON

Abstract

An ionic liquid assisted strategy for the synthesis of zeolitic material is reported. This strategy is a solid state synthetic method and the ionic liquid is employed as structure directing agent. A TON-type zeolite, which contains one-dimensional 10-member-ring, is successfully synthesized with the assistance of the ionic liquid, 1-ethyl-3-methylimidazolium bromide. This finding improves our understanding about the challenge of ionothermally synthesizing siliceous and aluminosilicate zeolites.

Keywords: Ionic liquids, Green chemistry; Solid-phase synthesis; Synthetic methods; Zeolites.

Figure 1

(a) TON type zeolite structure viewed along the 10-member ring channels. (b) Reported SDA structure for the synthesis of ZSM-22.[52] (c) Structure of the ionic liquid for the ionic liquid assisted synthesis of TON zeolite in this work.

Figure 2

PXRD patterns of (a) simulated TON type structure; (b) as-made pure TON sample (No. 7); (c) as-made pure TON sample synthesized with addition of water (No. 8) and (d) as-made TON sample which contains impurity of *MRE (No. 2, the asterisks indicate the reflections from the impurity).

Figure 3

SEM images of as-made TON crystals, which are taken at (a) low magnification (Scale bar is 50 μm) and (b) high magnification (scale bar is 10 μm).

Figure 4

²⁷Al MAS NMR spectra of calcined TON-zeolite obtained from (a) sample 5, (b) sample 7, and (c) sample 10.

Figure 5

¹³C MAS NMR spectrum of as-synthesized TON-zeolite from sample 7: the inserted figure shows the structure of the Emim⁺ cation and the corresponding carbon atoms to the resonances.

Figure 6

TGA curve of as-made TON-zeolites calcined to 800 °C in air.

Figure 7

N₂ isothermal plots of calcined TON-zeolites.