Saturated Nitrous Oxide

The next experiments consisted of irradiating the unbleached TMP pulp suspension in the presence of 1% hydrogen peroxide or 0,3% sodium borohydride. This was done to measure the influence of an oxidizing and a reducing chemical co-irradiated with the pulp suspension. Also, H202 is known to react with e solv to produce OH (equation 8). The effect of saturated nitrous oxide in pulp suspension was also studied. In presence of yrays, N20 is known to react with e-solv to generate OH. The experimental results are shown in Figure 5. 

If an aqueous solution of nitrourea is boiled, nitrous oxide escapes and the cyanic acid which is produced escapes in part, polymerizes in part, and in part remains in the aqueous liquid where it may react with various substances which may be introduced. If aniline is added to a saturated... 

By pulse radiolysis of nitrous oxide-saturated aqueous solutions of ferricyanide (2 X 10 " M) and various alcohols (0.1 M), Adams and Willson " were able to obtain absolute rate coefficients for the ferricyanide oxidation of the radicals derived from the alcohols by attack of the solvent irradiation product, OH-. 

The complexed halide atoms are produced by high energy radiation in solutions of colloids that contain halide anions X and are saturated with nitrous oxide. Hydrated electrons formed in the radiolysis of the aqueous solvent react with NjO according to NjO -f e -f H O - Nj -t- OH -I- OH to form additional OH radicals. Ions X are oxidized by OH, the atoms X thus formed react rapidly with X to yield XJ radicals. 

Nitrous oxide Nitric oxide Sulfur dioxide Standardized smoke Saturated and Olefinic Hydrocarbons Ozone... 

Charge alteration on the surfaces of nanosized metallic silver particles has been investigated by simultaneously monitoring absorption and conductivity changes during pulse-radiolytic experiments [506]. Pulse radiolysis of a nitrous-oxide-(N20) saturated aqueous solution of 3.0 nm diameter metallic silver particles containing 0.2 M 2-propanol resulted in electron injection to the colloid. NzO functions to double the yield of hydroxyl radicals ( OH) generated in water... 

The behavior of nitrous oxide during irradiation seems quite unusual. Whereas, as an irradiation atmosphere, 18 types of well-known inorganic gases and 4 types of saturated hydrocarbon gases were tested previously, the species which evidently showed such a singular effect were limited to nitrous oxide and xenon. In the work reported here, three types of polymers having different types of molecular structure were examined, but examination showed many points of similarity in the behavior of nitrous oxide. 

Andrews J, Martin-Bertram El, Elagen U (1984) SI nuclease-sensitive sites in yeast DNA an assay for radiation-induced base damage. Int J Radiat Biol 45 497-504 Antoku S (1983) Radiosensitization and radioprotection of E. coli by thiourea in nitrous oxide saturated suspensions. Int J Radiat Biol 43 451-458... 

Roots R, Chatterjee A, Blakely E, Chang P, Smith K, Tobias C (1982) Radiation responses in air-, nitrous oxide-, and nitrogen-saturated mammalian cells. Radiat Res 92 245-254 Roots R, Chatterjee A, Chang P, Lommel L, Blakely EA (1985) Characterization on hydroxyl radical-induced damage after sparsely and densely ionizing irradiation. Int J Radiat Biol 47 157-166 Roti Roti JL, Cerutti PA (1974) Gamma-ray induced thymine damage in mammalian cells. Int J Radiat Biol 25 413-417... 

Irradiation Procedure. 30% w/w solutions of poloxamer were prepared in distilled water by the cold process and saturated with nitrous oxide. This agent is a known scavenger of hydrated electrons and is known to enhance crosslinking of poly(oxyethylene) chains (9). Vials containing these solutions were irradiated at ambient temperature in a 2000 Ci ° Co source at a dose rate of 0.5 Mrad h- Physicochemical measurements were performed on solutions prepared by dilution of these irradiated samples. 

Nitrous oxide is relatively soluble in water (2 x 10 2 M at atmospheric pressure), it reacts very rapidly with eaq( 7 x 109 M 1 s 1) and is practically inert toward OH and H (for the latter, k < 104 M 1 s 1). Because of partial scavenging of e q from the spurs G(OH) in N20-saturated solutions is 6-0. Hydrogen peroxide also converts ejq into OH very efficiently [reaction (6)], but it has... 

There are very few cases of reactions of zero total order, and so these equations do not have wide application. Most of the known cases involve heterogeneous reactions occurring on surfaces, such as the decomposition of nitrous oxide gas on hot platinum wire, 2N2O 2N2 + O2, and the de-e.omposition of ammonia gas on a hot platinum wire, 2NH3 N2 + 3H2. The explanation seems to be that the reaction occurs only at the surface of the catalyst, and if the surface becomes saturated at a given gas or liquid concentration, further increase in the concentration in these phases cannot further change the surface concentration and so, beyond this point, the reaction seems to proceed at a rate independent of concentration in the gas phase. 

Fig. 4. Absorption kinetics over the time range of 1.7 ms of (SCN) " at 515 nm in an aqueous solution of 10 M of thiocyanate saturated with nitrous oxide after a 5-ps pulse of The dose was 4 Gy/pulse and the number of accumulations was 3899 with a repetition rate of 20 Hz. ...

Nitrous oxide saturation in surface waters of the Bay of Bengal is relatively smaller, averaging 125% (range 89-214%). The modest supersaturation, presumably caused by the strong thermohaline stratification, supports a lower flux to the atmosphere (0.04-0.12 Tg N2O year ) from the Bay of Bengal than that from the Arabian Sea (Naqvi et al., 1994). 

Figure 16.10 (A) Nitrous oxide (N2O) concentrations and isotopic composition for water samples collected at Station ALOHA. [Left] Depth profile of N2O showing a distinct mid-depth maximum of 60 nM coincident with the dissolved oxygen minimum. [Center] N isotope composition of N2O. [Right] 0 isotope composition of N2O. Data from Dore et al. (1998) and B. Popp and J. Dore (unpublished). (B) N2O saturation state, expressed as a percentage of air saturation, for the upper portion of the water column at Station ALOHA during the period September 1992— September 1994. The vertical dashed line indicates equilibrium (100% saturation) with atmospheric N2O. With the exception of one measured value on cruise HOT-45, all determinations indicate significant N2O saturation relative to the atmosphere which implies both a local source and a net ocean-to-air gas flux.From Dore and Karl (1996a).

Knight and Sutton (see section 5.12) in their study of y-ray irradiation of saturated solutions of nitric oxide examined the effect of adding nitrous oxide to the solution. From the results obtained in these experiments they were able to estimate the ratio 152/ 154 = 2.5+0.2, where ki64 refers to... 

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