Silica plasma synthesis

Gas-phase nucleation Flame synthesis of particles (e.g., carbon black, silica) cluster formation in chemical vapor deposition manufacture of high-purity silicon cluster structure and energetics plasma synthesis of refractory materials and coatings. 

Most of the plasma conversion processes are conducted after the discharge, where only the energy-carrier gas (often argon) is heated up (see Section 7.5.5). Conversion of a solid oxide into a carbide can be also performed inside of the RF-ICP discharge. As an example, consider the plasma synthesis of silicon carbide from silica in the presence of CH4 and H2 (Evans etal., 1968 Ttrmanov, 1981) ... 

Kwakman et al. [65] described the synthesis of a new dansyl derivative for carboxylic acids. The label, N- (bromoacetyl)-A -[5-(dimethylamino)naphthalene-l-sulfonyl]-piperazine, reacted with both aliphatic and aromatic carboxylic acids in less than 30 min. Excess reagent was converted to a relatively polar compound and subsequently separated from the derivatives on a silica cartridge. A separation of carboxylic acid enantiomers was performed after labeling with either of three chiral labels and the applicability of the method was demonstrated by determinations of racemic ibuprofen in rat plasma and human urine [66], Other examples of labels used to derivatize carboxylic acids are 3-aminoperylene [67], various coumarin compounds [68], 9-anthracenemethanol [69], 6,7-dimethoxy-l-methyl-2(lH)-quinoxalinone-3-propionylcarboxylic acid hydrazide (quinoxalinone) [70], and a quinolizinocoumarin derivative termed Lumarin 4 [71],... 

Plasma chemical synthesis, 1 717 Plasma chemical vapor deposition (PCVD), in fiber optic fabrication, 11 139-140 Plasma coatings, 5 665 Plasma deposition, in vitreous silica manufacture, 22 414, 415 Plasma derivatives, 12 129t... 

Niobium and titanium incorporation in a molecular sieve can be achieved either by hydrothermal synthesis (direct synthesis) or by post-synthesis modification (secondary synthesis). The grafting method has shown promise for developing active oxidation catalyst in a simple and convenient way. Recently, the grafting of metallocene complexes onto mesoporous silica has been reported as alternate route to the synthesis of an active epoxidation catalyst [21]. Further the control of active sites, the specific removal of organic material (template or surfactant) occluded within mesoporous molecular sieves during synthesis can also be important and useful to develop an active epoxidation catalyst. Thermal method is quite often used to eliminate organic species from porous materials. However, several techniques such as supercritical fluid extraction (SFE) and plasma [22], ozone treatment [23], ion exchange [24-26] are also reported. 

Despite the efficiency and purity of this reaction, however, our engineering group required that residual OsOx contaminants be purged not only from the synthetic products but also from large-scale multipurpose production equipment. Inductively coupled plasma mass spectrometry accurately determined residual osmium levels and could be used to monitor residuals to as low as 0.04 ppm. Silica gel filtration of reductive amination product 13 (from the next step) effectively removed all residual osmium (< 0.04 ppm). Nevertheless, dedicated equipment or facilities would be required for this step if the synthesis were to be considered for commercial manufacture.34... 

Another recent report describes the large scale synthesis of ahgned carbon nanotubes, of uniform length and diameter, by passage of acetylene over iron nanoparticles embedded in mesoporous silica [107]. The latter two methods, based on the pyrolysis of organic precursors over templated/catalysts supports, are by far superior by comparison with plasma arcs, since other graphitic structures such as polyhedral particles, encapsulated particles and amorphous carbon are notably absent (Fig. 16). 

Analysis of nicotinic acid, nicotinamide, and its metabolites in biological materials, i.e., blood, plasma, urine, and tissues, is important in studies on biochemical pathways (Hengen and deVries, 1985). Finder et al. (1971) described several paper and thin-layer chromatographic systems useful for the differentiation of nucleotides in tissues derived from nicotinamide and nicotinic acid. Hengen and deVries (1985) provided a table summarizing the Rp values of nicotinic acid, nicotinamide, and various intermediates of NAD+ and NADP-I- synthesis for both paper and thin-layer chromatography. Haworth and Walmsley (1972) used two-dimensional TLC on silica gel for the identification of tryptophan metabolites in urine and resolved 32 compounds including nicotinic acid and nicotinamide. Kala et al. (1978) used silica gel TLC to examine urine for nicotinic acid and its metabolites after administration of nicotinyl alcohol. They... 

Jiao, F. Frei, H. (2009). Nanostructured Cobalt Oxide Clusters in Mesoporous Silica as Efficient Oxygen-Evolving Catalysts. Angew. Chem., Vol. 121, pp. 1873-1876 Karthikeyan, J. Berndt, C.C. Tikkanen, J. Reddy, S. Herman, H. (1997). Plasma Spray Synthesis of Nanomaterial Powders and Depwsits. Mater. Sci Eng. A, Vol. 238, pp. 275-286... 

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