Nitric oxide catalysis

Tajima, N., Hashimoto, M., Toyama, F. et al. (1999) A theoretical study on the catalysis of Cu-exchanged zeolite for the decomposition of nitric oxide, Phys. Chem. Chem. Phys., 1, 3823. 

Shiny silvery metal that is relatively soft in its pure form. Forms a highly resistant oxide coat. Used mainly in alloys, for example, in construction steel. Tiny amounts, in combination with other elements such as chromium, makes steel rustproof and improves its mechanical properties. Highly suited for tools and all types of machine parts. Also applied in airplane turbines. Chemically speaking, the element is of interest for catalysis (for example, removal of nitric oxides from waste gases). Vanadium forms countless beautiful, colored compounds (see Name). Essential for some organisms. Thus, natural oil, which was formed from marine life forms, contains substantial unwanted traces of vanadium that need to be removed. 

Simultaneous generation of nitric oxide and superoxide by NO synthases results in the formation of peroxynitrite. As the reaction between these free radicals proceeds with a diffusion-controlled rate (Chapter 21), it is surprising that it is possible to detect experimentally both superoxide and NO during NO synthase catalysis. However, Pou et al. [147] pointed out that the reason is the fact that superoxide and nitric oxide are generated consecutively at the same heme iron site. Therefore, after superoxide production NO synthase must cycle twice before NO production. Correspondingly, there is enough time for superoxide to diffuse from the enzyme and react with other biomolecules. 

Marletta, M. A., Nitric oxide synthase aspects concerning structure and catalysis, Cell 78 (1994), p. 927-930... 

Non-noble metals such as Ni, Co, Mo, W, Fe, Ag and Cu have been added to zeolites for use in catalysis. In addition to CO, nitric oxide (NO) has been shown to be a good adsorbate for probing the electronic environment of these metals. When NO chemisorbs on these metals, it can form mononitrosyl (M-NO) and dinitrosyl species (ON-M-NO). The monontrosyl species has a single absorption band and the dinitrosyl species has two bands due to asymmetric and symmetric vibrational modes of the (ON-M-NO) moiety. Again, there have been many studies reported in the literature on the use of NO and/or CO adsorption on non-noble metals supported on zeolites and they are too numerous to list here. Several examples have been selected and summarized to provide the reader with the type of information that can be provided by this method. 

Nitrous acid catalysis also takes place in the nitration of such compounds (naphthalene) that are unable to undergo nitrosation on the given conditions or whose nitrosation proceeds slower than nitration. As accepted, the nitrosonium ion is formed from HNOj in acid media. The nitrosonium ion oxidizes an aromatic substrate into a cation-radical and transforms into nitric oxide. The latter reduces nitronium cation to nitrogen dioxide that gives a a-complex with the aromatic cation-radical ... 

The thiol-dependent release of nitric oxide may well involve metal catalysis from trace contamination of copper or iron in buffers. The disulfide radical may also reduce another nitrosothiol to produce more nitric oxide. 

Pufahl, R. A., and Marietta, M. A. (1993). Oxidation of N -Hydroxy-L-arginine by nitric oxide synthase Evidence for the involvement of the heme in catalysis. Biochem. Biophys. Res. Commun. 193, 963-970. 

Gttretski, J., and Hollcx her, T. C. (1991). Catalysis of nitrosyl transfer by denitrifying bacteria is facilitated by nitric oxide. Biochem. Biophys. Res. Commun. 175, 901-905. 

From the thermodynamic data of Appendix C, show that the product of the reaction of ammonia gas with oxygen would be nitrogen, rather than nitric oxide, under standard conditions and in the absence of kinetic control by, for example, specific catalysis of NO formation by platinum. (Assume the other product to be water vapor.)... 

Nitric Acid Catalysis in the Oxidation of Aromatic Hydrocarbons... 

Air Oxidation of Alcohols to Esters via Bromine-Nitric Acid Catalysis... 

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