Tetrapropylammonium fluoride

Silicalite-1 was synthesised according to published recipe [5], Fumed silica was added to an aqueous solution of tetrapropylammonium bromide and ammonium fluoride, and... 

In an attempt to produce TS-1 at low cost, alternative, cheaper sources of Ti and Si and other bases such as binary mixtures of (tetrabutylammonium and tetraethylammonium hydroxides), (tetrabutylphosphonium and tetraethylpho-sphonium hydroxides), (tetrapropylammonium bromide and ammonia, water, hexanediamine, n-butylamine, diethylamine, ethylenediamine, or triethanolamine) in place of TPAOH have been used (284—294). TS-1 was synthesized in the presence of fluoride ions but the material thus formed contained extraframework Ti species (295-297). 

Dissolved titanium method. Hydrothermal synthesis using tetrapropylammonium peroxytitanate (prepared from TEOT, distilled water, 30% aqueous H2O2, and 25% aqueous TPAOH) as the source of Ti and colloidal silica (Ludox AS-40) as the source of Si and TPAOH as template. All additions done at 278 K Preparation using TiCl2, 14% aqueous TPAOH, 30% colloidal silica, and demineralized water Preparation at low pH using fluoride ions as mineralizing agent... 

Starting materials for the direct synthesis of (Si,B)-ZSM-5 were fumed silica (Cabosil), tetrapropylammonium bromide (TPA-Br), ammonium fluoride and orthoboric acid (16). The source of silica was mixed with TPA-Br and water and then a mixed solution of NH4F and H3BO3 was added under vigorous stirring. The resultant gel was homogenized for 1.5 h and transferred into a Teflon-lined stainless steel autoclave which was then heated at 200°C for 17 days. Zeolite crystals were washed, dried at 60°C and hydrated in a desiccator. 

Figure 6. Effect of extra-framework material on XRD powder patterns. Calculated XRD patterns for ZSM-5 with and without ordered tetrapropylammonium and fluoride ions in the unit cell.

Chromium silicaiite has been prepared via three different routes, NH3, F, H2SO4 (see text). However, here we describe the use of the fluoride anion route. 18.1 g of Aerosil 200, 2.5 g of ammonium fluoride, 10 g of tetrapropylammonium hydroxide were added to DMW (178 ml), and the mixture stirred for 18 h. (solution A). Chromium(lll) chloride (2.2 g in 14 ml of DMW) was added to solution A, and aged in an homogenizer for 30 minutes. The mixture was then placed in a 300 ml Teflon bottle, and placed in a stainless steel autoclave, and heated at 169 °C under autogeneous pressure for 25 days. After the reaction was quenched, the green solid was filtered off, and the mother liquor diluted with hot water to facilitate isolation of the material. The product was dried at 70 °C for 12 h. under vacuum, followed by calcination at 550 °C for 24 h. The xrd pattern was in agreement with a ZSM-5 type zeolite structure. 

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