Sample records for phenylhydroxylamine
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The fate of phenylhydroxylamine in human red cells.
Kiese, M; Taeger, K
1976-01-01
Phenylhydroxylamine added to human red cells under aerobic conditions and in the presence of glucose was partly reduced to aniline. About half the hydroxylamine was recovered as amine after a 2-hr incubation. The aniline, after acetylation, was identified as acetanilide by melting point, Rf-value in TCL as well as UV, IR, and NMR spectroscopy. The fate of the remaining phenylhydroxylamine was followed by use of 14C-labeled phenylhydroxylamine. About 30% of the total radioactivity was bound to hemoglobin or other proteins and about 20% was found in highly polar low-molecular substances which were insoluble in organic solvents. The elucidation of the sites at which phenylhydroxylamine was bound to hemoglobin was complicated by the lability of the bonds. When purified human hemoglobin had reacted with radioactive phenylhydroxylamine, large proportions of the radioactivity bound to hemoglobin were removed by treatment with acid or with PMB for separation of alpha- and beta-chains. The radioactive compound liberated from hemoglobin by acid was found to be aniline. After reaction with phenylhydroxylamine the number of SH groups titrable with PMB was found to be diminished. Pretreatment of hemoglobin with N-ethylmaleimide or PMB decreased the amount of phenylhydroxylamine bound to hemoglobin but did not fully prevent the reaction. Tryptic digestion of hemoglobin after reaction with radioactive phenylhydroxylamine yielded tryptic peptides with lower specific activity than that of hemoglobin. Chymotryptic digestion of the tryptic core yielded a core with specific activity much higher than that of hemoglobin. Fingerprinting of the tryptic or chymotryptic hydrolyzates showed the presence of peptides with high and other ones with low or no radioactivity and of radioactive compounds which did not react with ninhydrin. In the covalent binding of phenylhydroxylamine to globin the SH group beta93 plays an important role, but other yet unknown sites are also reactive.
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NASA Astrophysics Data System (ADS)
Romanenko, Yu. E.; Merkin, A. A.; Komarov, A. A.; Lefedova, O. V.
2014-08-01
The kinetics of the hydrogenation of intermediates in the reduction of nitrobenzene in aqueous 2-propanol with acetic acid and sodium hydroxide additions on nickel catalysts was studied. A kinetic description of liquid-phase hydrogenation of azobenzene and phenylhydroxylamine was suggested. A kinetic model was developed. The dependences that characterize the variation of the amounts of the starting compound, reaction product, and absorbed hydrogen during the reaction were calculated. The calculated values were shown to be in satisfactory agreement with the experimental values under different reaction conditions.
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NITROBENZENE CARCINOGENICITY (1998)
Nitrobenzene (NB, CAS No. 98-95-3) oxidizes to p-aminophenol and p-nitrophenol in animals and humans, while being reduced also to nitrosobenzene, phenylhydroxylamine, and aniline. The reductants are known to cause methemoglobinemia and anemia. NB is negative for mutagenicity syst...
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The kinetics and mechanism of the ferrate(VI) oxidation of hydroxylamines.
Johnson, Michael D; Hornstein, Brooks J
2003-10-20
Aqueous solutions of potassium ferrate(VI) cleanly and rapidly oxidize hydroxylamine to nitrous oxide, N-methylhydroxylamine to nitrosomethane, N-phenylhydroxylamine to nitrosobenzene, and O-methylhydroxylamine to methanol and nitrogen. The kinetics show first-order behavior with respect to each reactant and a two term component representing acid dependent and independent pathways. A general mechanism involving intermediate formation coupled with a two-electron oxidation is proposed.
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Biotransformation and toxicity of aniline and aniline derivatives of cyanobacteria.
Cerniglia, C E; Freeman, J P; Van Baalen, C
1981-12-01
Agmenellum quadruplicatum strain PR-6 and Oscillatoria sp. strain JCM grown photoautotrophically in the presence of aniline metabolized the aromatic amine to formanilide, acetanilide and p-aminophenol. The metabolites were isolated by either thin-layer, gas-liquid or high pressure liquid chromatography and identified by comparison of their chromatographic, ultraviolet absorbance and mass spectral properties with those of authentic compounds. The toxicity of aniline derivatives towards Agmenellum quadruplicatum strain PR-6 indicated that the cyanobacterium was extremely sensitive to o-, m- and p-aminophenols, and phenylhydroxylamine.
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Eco-Contribution for the Production of N-Arylnitrones: Solvent-Free and Assisted by Microwaves
Reyes, Leonor; Corona, Sandra; Arroyo, Gabriel; Delgado, Francisco; Miranda, René
2010-01-01
A simple green approach for the production of benzylideneaniline oxides is offered. This contribution was performed via the condensation of phenylhydroxylamine with several aryl aldehydes, in the absence of both catalyst and solvent, and using microwave irradiation as the activating reaction mode. In addition, good yields of the products were achieved in a short time. It is also worth noting that the work-up procedure is simple and the products do not require further purification. Finally, an interesting comparison without the use of microwave irradiation is also discussed. PMID:20640169
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Gasita, S.M.; Iota, B.Z.; Malachkov, A.G.
1985-11-01
An extraction procedure has been developed for successive isolation of tungsten (/sup 178/W and /sup 181/W) and tantalum (/sup 179/Ta and /sup 182/Ta) isotopes without supports from ..cap alpha..particle-irradiated hafnium targets. The target, irradiated on a cyclotron, is dissolved in hydrofluoric acid. Tantalum isotopes are extracted with tributyl phosphate (TBP) from 1-5 M HF and are then reextracted with a 1:1 ammonia solution, and hydrofluoric acid is removed by heating. Tungsten isotopes are extracted with a chloroform solution or N-benzoyl-N-phenylhydroxylamine (BPHA) from 11-12 M H/sub 2/SO/sub 4/ or ..cap alpha..-benzoin oxime from 4.5-5.5 M H/sub 2/SO/sub 4/ and are thenmore » reextracted with a l:l ammonia solution. The yield of tungsten isotopes is not less than 95%, and the content of radioactive impurities of other isotopes is not more than 0.1%.« less
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Zhang, Qing; Liu, Yanming; Chen, Shuo; Quan, Xie; Yu, Hongtao
2014-01-30
Effective electrode materials are critical to electrochemical reduction, which is a promising method to pre-treat anti-oxidative and bio-refractory wastewater. Herein, nitrogen-doped diamond (NDD) electrodes that possess superior electrocatalytic properties for reduction were fabricated by microwave-plasma-enhanced chemical vapor deposition technology. Nitrobenzene (NB) was chosen as the probe compound to investigate the material's electro-reduction activity. The effects of potential, electrolyte concentration and pH on NB reduction and aniline (AN) formation efficiencies were studied. NDD exhibited high electrocatalytic activity and selectivity for reduction of NB to AN. The NB removal efficiency and AN formation efficiency were 96.5% and 88.4% under optimal conditions, respectively; these values were 1.13 and 3.38 times higher than those of graphite electrodes. Coulombic efficiencies for NB removal and AN formation were 27.7% and 26.1%, respectively; these values were 4.70 and 16.6 times higher than those of graphite electrodes under identical conditions. LC-MS analysis revealed that the dominant reduction pathway on the NDD electrode was NB to phenylhydroxylamine (PHA) to AN. Copyright © 2013 Elsevier B.V. All rights reserved.
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Li, Jie; Zhong, Li-feng; Tu, Xiang-lin; Liang, Xi-rong; Xu, Ji-feng
2010-05-15
A simple and rapid analytical method for determining the concentration of rhenium in molybdenite for Re-Os dating was developed. The method used isotope dilution-inductively coupled plasma-mass spectrometry (ID-ICP-MS) after the removal of major matrix elements (e.g., Mo, Fe, and W) from Re by solvent extraction with N-benzoyl-N-phenylhydroxylamine (BPHA) in chloroform solution. The effect on extraction efficiency of parameters such as pH (HCl concentration), BPHA concentration, and extraction time were also assessed. Under the optimal experimental conditions, the validity of the separation method was accessed by measuring (187)Re/(185)Re values for a molybdenite reference material (JDC). The obtained values were in good agreement with previously measured values of the Re standard. The proposed method was applied to replicate Re-Os dating of JDC and seven samples of molybdenite from the Yuanzhuding large Cu-Mo porphyry deposit. The results demonstrate good precision and accuracy for the proposed method. The advantages of the method (i.e., simplicity, efficiency, short analysis time, and low cost) make it suitable for routine analysis.
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Enhanced Nitrobenzene reduction by zero valent iron pretreated with H2O2/HCl.
Yang, Zhe; Ma, Xiaowen; Shan, Chao; Fang, Zhuoyao; Pan, Bingcai
2018-04-01
In this study a novel iron-based reducing agent of highly effective reduction toward nitrobenzene (NB) was obtained by pretreating zero valent iron (ZVI) with H 2 O 2 /HCl. During the H 2 O 2 /HCl pretreatment, ZVI undergoes an intensive corrosion process with formation of various reducing corrosion products (e.g., Fe 2+ , ferrous oxides/hydroxides, Fe 3 O 4 ), yielding a synergetic system (prtZVI) including liquid, suspensions and solid phase. The pretreatment process remarkably enhances the reductive performance of ZVI, where a rapid reduction of NB (200 mg L -1 ) in the prtZVI suspension was accomplished in a broad pH range (3-9) and at low dosage. Nitrosobenzene and phenylhydroxylamine are identified as the intermediates for NB reduction with the end-product of aniline. Compared with the virgin ZVI as well as another nanosized ZVI, the prtZVI system exhibits much higher electron efficiency for NB reduction as well as higher utilization ratio of Fe 0 . A rapid reduction of various nitroaromatics in an actual pharmaceutical wastewater further demonstrated the feasibility of the prtZVI system in real wastewater treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Asadollahi, Tahereh; Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji
2010-06-30
A novel dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFO) for separation/preconcentration of ultra trace amount of vanadium and its determination with the electrothermal atomic absorption spectrometry (ETAAS) was developed. The DLLME-SFO behavior of vanadium (V) using N-benzoyl-N-phenylhydroxylamine (BPHA) as complexing agent was systematically investigated. The factors influencing the complex formation and extraction by DLLME-SFO method were optimized. Under the optimized conditions: 100 microL, 200 microL and 25 mL of extraction solvent (1-undecanol), disperser solvent (acetone) and sample volume, respectively, an enrichment factor of 184, a detection limit (based on 3S(b)/m) of 7 ng L(-1) and a relative standard deviation of 4.6% (at 500 ng L(-1)) were obtained. The calibration graph using the preconcentration system for vanadium was linear from 20 to 1000 ng L(-1) with a correlation coefficient of 0.9996. The method was successfully applied for the determination of vanadium in water and parsley. Copyright 2010 Elsevier B.V. All rights reserved.
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Hepiegne, P; Dall'ava, D; Clement, R; Degros, J P
1995-06-01
A chemical separation method has been developed for the determination of (99)Tc in various types of radioactive wastes. Such a method includes (i) fusion with NaOH, (ii) extraction in a column containing methyltrioctylammonium chloride, (iii) extraction by solvent with N-benzoyl-N-phenylhydroxylamine and, (iv) measurement by inductively-coupled plasma mass spectrometry (ICP-MS). From the performance standpoint, the recovery of (99)Tc, using (99m)Tc as a yield tracer, is higher than 70%. This analytical method, as developed, ensures effective decontamination with respect to the radionuclides, insofar the decontamination factors are greater than 10(+5), whenever the residual activity may be measured. Taking into account a 3sigma counting error, the detection limit obtained with the ICP-MS technique is 1.9 mBq/ml; the method enabling hence to detect activities as low as 0.3 Bq/g, with analysed samples of 0.2 g and a radiochemical yield of 70%. Studies have been dedicated to the (99)Tc measurement, using the electrothermal vaporization ICP-MS technique, which lowers the detection limit by a factor 10, with the standard solution (0.3 pg/ml), compared with the previous ICP-MS technique.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Jensen, Stephen C.; Bettis Homan, Stephanie; Weiss, Emily A.
2016-01-28
This paper describes the use of cadmium sulfide quantum dots (CdS QDs) as visible-light photocatalysts for the reduction of nitrobenzene to aniline through six sequential photoinduced, proton-coupled electron transfers. At pH 3.6–4.3, the internal quantum yield of photons-to-reducing electrons is 37.1% over 54 h of illumination, with no apparent decrease in catalyst activity. Monitoring of the QD exciton by transient absorption reveals that, for each step in the catalytic cycle, the sacrificial reductant, 3-mercaptopropionic acid, scavenges the excitonic hole in ~5 ps to form QD•–; electron transfer to nitrobenzene or the intermediates nitrosobenzene and phenylhydroxylamine then occurs on the nanosecondmore » time scale. The rate constants for the single-electron transfer reactions are correlated with the driving forces for the corresponding proton-coupled electron transfers. This result suggests, but does not prove, that electron transfer, not proton transfer, is rate-limiting for these reactions. Nuclear magnetic resonance analysis of the QD–molecule systems shows that the photoproduct aniline, left unprotonated, serves as a poison for the QD catalyst by adsorbing to its surface. Performing the reaction at an acidic pH not only encourages aniline to desorb but also increases the probability of protonated intermediates; the latter effect probably ensures that recruitment of protons is not rate-limiting.« less
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Noguchi, M; Nitoh, S; Mabuchi, M; Kawai, Y
1996-04-01
In experiment 1, the amount of aniline (AN) metabolites in the primary cell culture medium of the liver cells obtained from ethionine (ET)-treated rats was compared with that of the control (normal) rats. Although the metabolites detected in both groups were p-aminophenol (p-AP), N-acetyl-p-AP (AAP), acetoanilide (AAN), AAP-glucuronide (AAPG), phenylhydroxylamine sulfate (PHAS) and p-AP-glucuronide (p-APG), the amount of AAP was lower and that of p-APG was markedly higher in the ET-treated rats than in the control rats. In experiment 2, phenobarbital (PB) was orally administered to the ET-treated and control rats at a dose of 100 mg/kg. The time course changes in AN metabolites in the primary cell culture medium of liver cells obtained at 2 or 48 hr after PB treatment were compared with those without PB treatment. In the ET-treated rats, the amount of PHAS was slightly higher at 2 hr after PB treatment, and that of AAP was lower and that of p-APG was higher at 48 hr after PB treatment as compared with those without PB treatment. In the control rats, the amounts of AAP, AAN, p-AP and p-APG at 2 hr after PB treatment remained lower than those without PB treatment, and that of AAP was markedly lower and that of p-APG was higher at 48 hr after PB treatment as compared with those without PB treatment. These findings indicated greater detoxication in the primary liver cell culture in the ET-treated rats than in the control rats. Furthermore, detoxication was greater in the primary cell culture of liver cell obtained from the ET-treated rats after PB treatment than from those without PB treatment, because the production of acetylates (AAP) decreased and p-APG increased (induction of conjugated enzyme) in the PB treatment group.