Synthesis of zeolite Beta from nonalkaline fluoride aqueous aluminosilicate gels

Critical Factors in the Seed‐Assisted Synthesis of Zeolite Beta and “Green Beta” from OSDA‐Free Na+–Aluminosilicate Gels

“…CBS1 exhibits two signals at d = 53 and 0 ppm, which correspond to the tetrahedrally and octahedrally coordinated aluminum, respectively (Figure 5 a). [20,31,38] The latter is possibly formed by de-alumination upon calcination of TEA + -containing beta seeds. [17,42] In contrast, the OSDA-free beta (Figure 5 b) and green beta (Figure 5 c) products exhibit only one signal centered at 57 ppm, which indicates that all aluminum atoms are incorporated in the *BEA zeolitic framework and that no extraframework aluminum exists in both products.…”

“…Control over the Si/Al ratio of zeolite beta has therefore been extensively investigated by many researchers, and the ratio can now be controlled in the range of 3.9:1 to infinity by various methods. [14][15][16][17][18][19][20][21][22][23][24][25][26][27]38] In these syntheses, TEAOH has been used as the OSDA; it is known that the TEA + cation has a vital role in the formation of the zeolite beta framework, and about six TEA + cations per unit cell are usually occluded in the final product. [28][29][30][31] However, from a practical viewpoint, the quantity of TEAOH used in the synthesis of zeolite beta should be as low as possible because it is expensive, it gives rise to complex synthesis processes, and it requires high energy consumption, which leads to a high environmental burden.…”

Investigations of the formation of zeolite ZSM-39 (MTN)

“…The facts that the Si signals due to T1 and T2 sites in the MTN structure appear in the direct-excitation 29 Si NMR spectra later than the T3 Si and that 19 F NMR signal at due to Foccluded in [5 12 ] cages (see below) only appears after 66 h heating clearly indicates that the [5 12 6 4 ] cages form first and they only join together in a later stage to form the 3D MTN structure. It is apparent that the ZSM-39 crystallizes very quickly as soon as the [5 12 (Figure 4), the 57.2 ppm peak is assigned to the -CH 3 carbon atom in the TMA + ion which is trapped in the framework of crystalline ZSM-39, since this peak can be seen in the final product as well. The 56.2 ppm signal is due to the -CH 3 resonance of TMA + ions that are still surrounded by the amorphous gel present in the reaction mixture because the reaction is not yet completed.…”

“…Over the past few decades, there have been attempts to synthesize zeolites in non-aqueous systems containing organic solvents or in mixed solvents. [11][12][13][14][15][16][17][18] More recently, a newer synthetic strategy using ionic liquid (IL) to prepare framework structures has been developed. One class of ILs is deep eutectic solvents (DESs).…”

Compositional and kinetic studies on the crystallization of zeolite beta using cost-efficient TEABr without seed under static and stirred conditions

“…Like other high silica zeolite, however, it requires organic template. Various organic templates such as tetraethylammonium hydroxide (TEAOH) [1,[4][5][6][7][8][9][10][11][12][13][14][15][16], dibenzyl 1,4-diazabicyclo [2.2.2]octane [17,18] [19,20] and dibenzyl dimethylammonium cation [21] have been reported. In addition, various co-templating systems, such as TEAOH and TEABr [22], TEAOH and TEAF [23], TEABr and seed [24], TEABr, diethanolamine and seed [25], TEABr, triethanolamine and TEAOH [26], TEABr, NH 4 [27], etc.…”