Hot oxygen atoms

Translationally hot species may also have enhanced reaction rates. Reuben and Linnett have proposed that such hot oxygen atoms are formed in the thermal decomposition of nitrous oxide, and that these react at an accelerated rate with further nitrous oxide. Williams and Ogg have shown that hydrogen atoms with 42 kcal.mole" of translational energy react at an enhanced rate with hydrogen iodide, and have demonstrated a similar effect in the reactivity of hot methyl radicals. 

A recent study of the vibrational-to-vibrational (V-V) energy transfer between highly-excited oxygen molecules and ozone combines laser-flash photolysis and chemical activation with detection by time-resolved LIF [ ]. Partial laser-flash photolysis at 532 nm of pure ozone in the Chappuis band produces translationally-hot oxygen atoms 0( P). In the chemical-activation step they react with ozone to form an electronic ground-state Oi(X S , u")with up to v" = 27 quanta of vibrational excitation in an excess of thermally populated... 

Raman spectroscopy has shown that 25 3 % of the available energy (3.27 eV) appears as vibrational energy. It was shown that the vibrationally excited N2 is a primary product of the reaction and is not produced by collisions of translationally hot oxygen atoms with N2. 

Acetylene is oxidized to ketene by hot air (24JCS(125)1534). Oxirene is probably not involved since molecular oxygen is not a donor of singlet oxygen atoms (see the remarks on this point in (64JA4866)). 

The two types of hot eorrosion eause different types of attaek. High-temperature eorrosion features intergranular attaek, sulfide partieles and a denuded zone of base metal. Metal oxidation oeeurs when oxygen atoms eombine with metal atoms to form oxide seales. The higher the temperature, the more rapidly this proeess takes plaee, ereating the potential for failure of the eomponent if too mueh of the substrate material is eon-sumed in the formation of these oxides. 

Many chemical changes are reversible reactions. Burning carbon in the form of coal, for instance, is highly exothermic. Oxygen atoms combine with carbon to produce carbon dioxide and heat. But passing carbon dioxide over a bed of hot carbon causes an endo-... 

The above conclusion was confirmed by control experiment. It is well known [47] that freshly deposited silver films are very efficient in adsorption of atomic oxygen at room temperature. Therefore, the attachment covered by Ag-film similar to that with a Co304-covering should completely stop the flux of oxygen atoms. (The experiment with the known source of oxygen atoms - hot Pt-filament - confirms the efficiency of above attachment). It occurred [44] that in case of particles leaving the Ag surface such an attachment completely shuts down the flux of particles from the surface of the sample under investigation. 

The cleavage of kojic acid by hot alkali, to fragments containing one to three carbon atoms, could not be definitely shown to commence at the ring oxygen atom, but what was said earlier about y-pyrones in general renders this conclusion probable. 

Hydrothermal Of the hot-water systems that are present at acUve mid-ocean spreading centers. Hydroxyl A chemical group composed of an oxygen atom bound to a hydrogen atom (i.e., -OH). Hypersaline Water with a salinity in excess of that at which halite will spontaneously precipitate. Hypoxic Waters with dissolved oxygen concentraUons less than 2 to 3 ppm (2mL/L). 

NbCl5 and TaCls metallate porphyrins in benzonitrile at 210 °C and in phenol at 295 °C respectively.173 38 The trichloride is hydrolyzed to M(Por) 2(0)3 in which three oxygen atoms are bridging two metal ions.21 The tn-p-oxo dimer dissociates to oxoacetates MO(Por)(OCOMe) in hot acetic acid and to trihalides M(Por)X3 in hydrohalic acid (HF, HC1, HBr).17a 38 NbO(OEP)X (X = I3, F, acac) complexes are also known (Scheme 11).39... 

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