Oxynitrides synthesis

Vapor—sohd reactions (13—17) are also commonly used ia the synthesis of specialty ceramic powders. Carbothermic reduction of oxides, ia which carbon (qv) black mixed with the appropriate reactant oxide is heated ia nitrogen or an iaert atmosphere, is a popular means of produciag commercial SiC, Si N, aluminum nitride [24304-00-3], AIN, and sialon, ie, siUcon aluminum oxynitride, powders. 

Generally, metal nitride and oxynitride catalysts have been prepared by the temperature programmed ammonolysis method. This technique was originally applied by Volpe and Boudart to M0O3 precursors to produce y-Mo2N which was pseudomOrphic with the precursor, with surface areas up to 225 m g The resultant surface area of materials is known to be a strong function of the synthesis parameters as demonstrated in Table 1. ... 

Antonelli and co-workers have recently demonstrated that room temperature stoichiometric ammonia synthesis is possible with their mesoporous titanium and niobium oxide catalysts. In this study, they proposed that the ammonia species are formed via the reaction activated nitrogen with the underlying moisture of the support. Reversible, inter-conversion of and NH2 species via exposure to moist air for aluminophosphate oxynitride catalysts has been observed by FTIR and XPS by Marquez and co-workers. There has been a lot of interest in the literature in the development of novel routes for the low temperature stoichiometric conversion of nitrogen to ammonia, e.g.. However, in principle this could be realised by the nitridation of Li, followed by hydrolysis, although the kinetics would be very slow. 

Nitridated silica surfaces are very important in the semi-conductor and microelectronic industries. However, direct ammoniation of silica is -so far- a very uncontrollable procedure the required reaction temperatures are very high (> 1500 K), a lot of side products are formed (typically Si2N20, silicon-oxynitride) and the nitride diffuses into the silica matrix. Direct nitridation of silica should therefore be considered as a bulk synthesis, and not as a surface modification technique. 

The method of choice for the synthesis of unsaturated arylsulfones is the Knoevenagel condensation of arylsulfonylalkanes with aldehydes. The condensation between aldehydes and phenylsulfonyl acetonitrile, has been performed in the presence of various solid base catalysts (MgO, Cs-exchanged X zeolite, Al-Mg mixed oxide, and aluminophosphate oxynitride) at 373 K in the absence of solvents.1641 The most active catalyst for this transformation was the aluminophosphate oxynitride, but MgO and the Al-Mg mixed oxide also were found to have excellent activity, yielding the Knoevenagel adduct in yields of 86 and 71 %, respectively, after 2 h in a batch reactor. 

Gundiah. G.. Madhav. G. V. Govindaraj. A. Rao, C. N. R. Synthesis and characterization of silicon carbide, silicon oxynitride and silicon nitride nanowires. J. Mater. Chem. 2002 12. 1606-1611. 

The last three chapters summarize unique structural and chemical features of a variety of glasses. They also provide an overview of the important aspects of the glass systems. Chapters 12 and 13 discuss respectively oxide and chalcogenide glasses particularly in view of their chemistry, structure and a number of special phenomena associated with them. In chapter 14, synthesis, structure and properties of halide, oxyhalide, oxynitride and metallic glasses are discussed. Some aspects of glass-like carbon have also been presented. 

In this work, we used oxynitride block catalysts produced by self-propagating high-temperature synthesis (SHS) [3,4] for purification of the gaseous mixtures modeling exhaust gases from carbon monoxide, hydrocarbons,and nitrogen oxide. 

In the present study, we will desribet the link between the nitridation parameters and the performances of oxynitrides for the synthesis of jasminaldehyde. Jasminaldehyde (a-amylcinnamaldehyde) is obtained through the aldol condensation of heptanal with benzaldehyde, in the liquid phase. It is a fine chemical of commercial interest [2], as it is used by the flavour and perfume industry. On top of its industrial interest, the aldol condensation reaction between heptanal and benzaldehyde is an interesting test reaction to assess the acid-base properties of heterogeneous catalysts. Heptanal is more reactive than... 

Gandia, LM Malm, R Marchand, R Conanec, R Laurent, Y Montes, M. Application of a new hydrogenated aluminophosphate oxynitride (AlPON) as a catalytic support for the one-step synthesis of methyl isobutyl ketone from acetone. Applied Catalysis A General, 1994 114, LI-L7. 

C. Synthesis of Silicon Nitride and Silicon Oxynitride Fibers from Polycarbosiianes... 

Synthesis of Silicon Nitride (Si3N4) and Oxynitrides by Non-Thermal Plasma Conversion of Silane (Sil-14)... 

Challenged by the successful syntheses of dihalides of Sm and Yb as well as of Eu, synthetic inorganic chemists sought to make SmO and YbO. Brauer et al. [52] summarized earlier efforts but this experienced team of synthetic inorganic chemists was unable to synthesize lower oxides of Nd, Sm, or Yb. Soon thereafter a claim was made for synthesis of YbO, also with the NaCl structure [53]. Within months two of these authors admitted that YbO was actually Yb20C [54]. (Similarly, claimed PuO and AmO appear to be oxycarbides or oxynitrides.) McCarthy and White [55] provided a thermodynamic basis for the successfiil synthesis of EuO and EU3O4 but not of corresponding oxides of other rare earths. 

Fuertes A (2010) Synthesis and properties of functional oxynitrides - Irom photocatalysts to CMR materials. Dalton Trans 39 5942-5948... 

Silicon nitride is receiving considerable attention as a structural ceramic, which requires a fully dense material, but it is also of interest to consider whether it could be prepared in high surface area forms. Our work in this direction has led to a synthesis of a high surface area silicon oxynitride. We summarise here the synthetic work and then report data on the stability of the surface. 

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