Surface area, silica materials

In an exploratory experiment, 13 different powder materials were tested in a FFB ACE unit. Most of the results were unremarkable except for three catalysts a low Z/M commercial maximum distillate catalyst (the same LZM catalyst used in the pilot riser experiment), a spray dried low surface area silica (inert) and the minimum aromatics breakthrough (MAB) catalyst. The inert material was included in the study to represent thermal cracking. The catalysts were steam deactivated in the fixed bed steamer prior to testing. Catalysts and the VGO-B feed properties are displayed in Tables 2.3 and 2.1, respectively. LCO aromatics were measured with 2D GC. Figures 2.7 through 2.9 illustrate the main results. 

Sandrofr. C L el ul "Gas Clusters in the Quantum Size Regime Growth on High Surface Area Silica by Molecular Beam Epiiaxy," Science. 391 l July 28. 1989). Vander Veen. M.R. "Gallium Arsenide Sandwich Lasers." Advanced Materials 7 Processes, 39 (May 19881. 

Catalyst particles generally consist of a metal deposited onto the surface of a support and are denoted by metal/support, e.g. Pd/C indicates palladium metal on a carbon support. Among the metals used for catalysis, Pd is often found to be the most active metal. (Augustine 1965) For example, in the aqueous hydrodechlorination of 1,1,2-trichloroethane, Pd catalysts achieved significantly more conversion than Pt or Rh catalysts. (Kovenklioglu et al. 1992) Catalyst supports can vary in shape, size, porosity and surface area typical materials include carbon, alumina, silica and zeolites. 

The TiVOx Catalyst. Industrial waste gases frequently contain nitrous oxide emissions (N0X). This pollutant can be removed by co-proportionation with ammonia in the presence of a suitable catalyst. Vanadia (vanadium oxide) is an active material to this end and titania (titanium oxide) is often used as a support because it also has a promoting effect. To improve this catalyst, and to make it cheaper, titania and vanadia were deposited on a high-specific-surface—area silica. The most successful version was obtained by co-impregnation of the active compounds. 

Experiments were performed on DC745U and M97 silica-filled silicone polymers as described elsewhere [1-5]. The gum stocks for all formulations were co-block polymers of dimethylsiloxane, diphenylsiloxane, methylphenylsiloxane, and/or methylvinyl siloxane. The gum stock was reinforced with high surface area silica filler and crosslinked with peroxide curing agents. These materials were tested in both new as well as service return conditions. 

Solid support for stationary phases robust inert material used as support for a liquid mobile phase, has a large surface area, common materials are silica gel for HPLC, processed brick and celite particles for GC. 

After their discovery in 1992 [38], ordered mesoporous silica materials received intense attention, finding a rich variety of applications in separation, catalysis, sensors, and devices [39, 40]. Because of their highly ordered structures, large pore size, and high surface areas, mesoporous materials are good candidates for... 

Reddy and Das made a silica-supported zirconocene catalyst in situ, by subliming ZrCl4 onto a high surface area silica, then adding NaCp. This catalyst was combined with an organically modified montmorillonite (Cloisite 20A), mixed with additional MAO (Al/Zr = 500). Propylene polymerization was conducted in the gas phase, at 8 bar and 70°C. Despite the absence of an obvious mechanism for interaction between the catalyst with the clay, or the presence of a solvent to swell the clay, the composite material was claimed to contain delaminated clay on the basis of decreased basal peak intensity in the XRD. The polypropylenes showed low melting points (132°C-134°C) consistent with large amorphous fractions. 

The physical properties of cured polysiloxane materials are dramatically influenced by fillers (1,2). So-called non-reinforcing (extenders) and reinforcing fillers are typically used the most common reinforcing filler is silica. High surface area silica, called fumed silica, is formed by burning the product mixture obtained from the trichlorosilane (TCS) reaction of equation 8. Only a small amount of untreated... 

---