Fluoride route

Sodium LAS synthesized via aluminum chloride catalysis dissolves better than sodium LAS from the hydrogen fluoride route. The main difference is the tetralin content. Dialkyltetralinsulfonates (DATs) function as hydrotropes and this influence can be larger than that of the 2-phenylalkane content. For a homolog (equal alkyl side chains), the higher the DAT content, the lower the... 

The double fluoride, ammonium hexafluorovanadate ((NH4)3VF6), forms from the oxide at 210 to 250 °C, but decomposes at 600 to 700 °C to yield pure vanadium fluoride. Examples of metal fluorides obtainable through the double fluoride route include uranium tetrafluoride, beryllium difluoride and the rare earth fluorides ... 

MFI-type zeolitee with Si PARTLY SUBSTITUTED by TIII(T=B. Al, Fe. Qa). The fluoride route can be used to prepare MFI-type zeolitea with... 

The fluoride route of synthesis seems very rich and already provided four among the six most open frameworks described up to now in the litterature in the category of microporous compounds (0 < A) VSB-1 [22] cloverite [11], ULM-5 [23] and ULM-16 [24] with tunnels limited by 24, 20,16 and 16 polyhedra respectively. These four solids are really porous, the porosity being generated by the elimination of the template either by thermal or chemical methods which preserve the inorganic framework. 

In the fluoride route, which was primitively applied to silica based and A1P04 and GaP04 materials, the first chemical parameter is the nature of the metallic species, since the reactivity of Si toward F is completely different from that of A1 or Ga. 

The fluoride route also works under "dry" conditions, i.e., in systems to which no water has been added [24, 25]. A typical synthesis system then consists only of silica, the SDA and NH4F, This solid mixture is filled into the autoclave and heated. Of course, the reaction of silica with NH4F to form fluoride-containing Si complexes liberates water, but the amount formed is very small. This may be important for SDAs that are sensitive to water. 

As for all other zeolite crystals prepared with the fluoride route, the crystals of the structure types FER TON and HTT are of very large size in the absence of seeds. The FER-type crystals are aggregates of plates, the size of which can be larger than 200 pm. The other structure types (TON and HTT) show a fibrous aspect, the length being over 100 pm for a diameter below 1 pm (Figure 5). 

Kessler et al. 1994 Fluoride route in the synthesis of microporous materials [24]... 

From that time, the synthesis of zeolites by the so-called fluoride route has developed to a large extent, with great contributions by Guth et It has been successfully appHed to pure-silica, alumi-... 

Structure-Direction Issues in the Fluoride Route to Pure-Silica Zeolites... 

However, there are at least two additional important structure-direction factors interplaying with that of fluoride in the synthesis of pure-silica zeolites by the fluoride route the OSDA and the degree of dilution of the synthesis gel. Villaescusa and Camblor have shown that the general concepts outlined above regarding structure-direction by OSD As can be successfully used in the search for new pure-silica materials, as shown for instance by the synthesis strategies that finally lead to the three-dimensional large pore zeolite ITQ-7. Nonetheless, we would like to point out at least one peculiarity, in this respect, of the fluoride route small cations may show by this route a rather specific structure-direction effect (like 1,3,5-trimethylimidazolium, which has a (C- -N)/N ratio of 8 but shows a rather large specificity towards zeolite ITQ-12 in fluoride aqueous medium). 

VAPO-11 — — Obtained via fluoride route Oxidation of ethylbenzene (199)... 

Villaescusa L, Camblor M (2003) The fluoride route to new zeolites. Recent Res Dev Chem 1 93-141 Wagner T, Waitz T, Roggenbuck J, Froba M, Kohl C-D, Tiemann M (2007) Ordered mesoporous ZnO for gas sensing. Thin Solid Films 515 8360-8363... 

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