sodium-nitrite and 4-nitrophenol

Oxidative degradation of p-nitrophenol (PNP) was investigated with NaNO(2) as the catalyst and dioxygen as the oxidizing agent in the presence of trichlorophenol (TCP). Although degradation of PNP alone was proved to be inefficient toward the NaNO(2)-mediated oxidative degradation system, when PNP in combination with TCP was used as the substrate, NaNO(2) showed relatively high catalytic activity for eradicating both PNP and TCP with molecular oxygen. Reaction conditions to the degradation system, e.g., temperatures, reaction time, pH, NaNO(2) and TCP concentrations were optimized. PNP could be highly efficiently degraded in the NaNO(2)/TCP/O(2) system (more than 99% removal for PNP) and the TOC removal of the mixture of PNP and TCP could reach 71% at 150 degrees C, 0.5 MPa oxygen pressure. Degradation products were determined, and 93% carbon atom was clarified. A plausible overall mechanism for the formation of active species is described, in which peroxylnitrite was believed to be a dominating active intermediate being responsible for destroying the substrates, PNP and TCP. The novel NaNO(2)-based concurrent oxidation system for PNP and TCP provides a potential application in treatment of multi-component industrial effluents.

Topics: Catalysis; Chlorophenols; Hydrogen-Ion Concentration; Models, Chemical; Molecular Structure; Nitrophenols; Oxygen; Sodium Nitrite

We examined the production of nitric oxide (NO) from various nitro-containing compounds (500 microM and 100 microM solutions in Krebs buffer, pH 7.4). Sealed vials containing solutions of NaNO2, N-nitro-L-arginine, 4-nitrophenol, BAY K 8644, or N-nitro-L-arginine methyl ester were stored in the dark, under normal room light, or were exposed to ultraviolet light (365 nm), for 30 min (24 degrees C). NO was measured in the vial headspace after 30 min, using a sensitive assay previously established in our laboratory. Production of NO was found to be dependent on the intensity of light exposure for all compounds, and the highest degree of light-induced production of NO was found for NaNO2 and BAY K 8644 solutions. Since NO is a relaxant of smooth muscle, these results help explain the increased sensitivity to relaxation by UV light of vascular and other types of smooth muscle in the presence of NaNO2, BAY K 8644 and N-nitro-L-arginine, as observed by other investigators.

Topics: 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; Arginine; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitro Compounds; Nitroarginine; Nitrophenols; Photochemistry; Sodium Nitrite; Ultraviolet Rays