Template-free synthesized samples

Some of the samples were synthesized ithout A190 . The syntheses with tetrapropylammonium iodide (TPA J ) as template were carried out with a varying Si09/Al90 ratio in the range 25 - 400. The batch composition of the template-free synthesis was... 

Muller (11) scanned a 200 n ZSM-5 crystal from a sample with a Si/Al ratio of 62, which is highly zoned with very little A1 in the core of the crystal (Fig. 4). A comparison of A1 distribution in ZSM-5 synthesized with and without a template (16) is shown in Fig. 5. The template free scan (Fig. 5 a) shows an almost uniform distribution of A1 while the crystal synthesized in a TPA base (Fig. 5b) shows a much higher A1 concentration in the core but is still highly zoned. Both crystals are considerably smaller than the one in Fig. 6. 

Sihcates with MFI structure were synthesized in alkali- and template-free medium by Wallau et al. [521] and characterized, inter alia, via IR spectroscopy. The zeohtes synthesized from template-containing gels showed almost exclusively Bronsted addity, whereas the samples produced from template-free synthesis mixtures possessed a large number of Lewis add sites. 

It has been previously reported [21, 22] that metal colloids are formed by radiochemical reactions in water/alcohol solutions, in which the reduction of metal salts takes place by solvated electrons and free radicals produced under UV or y-ray irradiation. Ichikawa et al. have applied this photoreduction method to the surface-mediated reaction of metallic ions and succeeded in synthesizing metal/aUoy nanowires in the constrained cavities of mesoporous supports such as FSM-16 and MCM-41 [18-20, 23-25]. The adsorbed water and alcohol work not only as solvents in the nanoscale silica void space but also as a source of reducing species for metallic ions to metals under UV-vis and y-ray [11, 18, 19] irradiation. The results indicate the dense formation of Pt nanowires inside the charmels of mesoporous supports, such as FSM-16, which act as the templates. In fact, no any Pt wire is observed on the external surface of FSM-16 or amorphous silica surface. Short wires, 10 nm long, are also observed as a minor species in the samples in the initial stage of UV and y-ray irradiation. 

TS-1 were synthesized following example 1 of the original patent [1] using tetraethyl-orthosilicate (98% Aldrich), tetraethylorthotitanate (Aldrich) and alkali-free tetrapropyl-ammonium hydroxyde solutions (TPAOH). The occluded templating molecules were removed from the zeolite channels upon calcination in air at 550°C for lOh. The Ti content was obtained by atomic absorption, after solubilization of the samples in HF-HCl solutions. 

A series of ZSM-5 zeolites synthesized using carbon black Black Pearls 2000 as secondary template was compared with ZSM-5 prepared by confined space synthesis and carbon-free ZSM-5. By secondary templating approach it is possible to prepare highly crystalline materials with mesopore diameter of 12 ran corresponding to the size of carbon black particles. Mesopore volume and mesopore surface area of obtained materials increase with increasing amount of carbon black in the reaction mixture. Observed decrease in micropore volume can be attributed to the increasing amount of Si04 tetrahedra on the mesopore surface. In the case of the sample prepared by eonfined space... 

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