The catalytic dehydrogenation of ethylbenzene to styrene is coupled with the catalytic hydrogenation of nitrobenzene to aniline in a simulated integrated reactor formed of two fixed beds separated by ...a hydrogen-selective membrane, where both hydrogen and heat are transferred across the surface of membrane tubes. A pseudo-homogeneous model of the two fixed beds predicts the performance of this novel configuration first proposed by Moustafa and Elnashaie Simultaneous production of styrene and cyclohexane in an integrated membrane reactor. Journal of Membrane Science 178 (1), 171–184. Both co-current and counter-current operating modes are investigated and the simulation results are compared with corresponding predictions for an industrial adiabatic fixed bed reactor operated at the same feed conditions. The conversion of ethylbenzene and the yield of styrene in the membrane reactor are predicted to exceed by a wide margin those in the industrial adiabatic fixed bed reactor. Aniline is also produced as an additional valuable product in a favorable manner, and autothermality is achieved within the reactor. The results suggest that coupling of these reactions could be feasible and beneficial. Experimental proof-of-concept is needed to establish the validity and safe operation of the novel reactor.
High concentrations of 2,4,6-trinitrotoluene (TNT) and related nitroaromatic compounds are commonly found in soil and groundwater at former explosive plants. The bacterium, Raoultella terrigena ...strain HB, isolated from a contaminated site, converts TNT into the corresponding amino products. Radio-HPLC analysis with ¹⁴CTNT identified aminodinitrotoluene, diaminonitrotoluene and azoxy-dimers as the main metabolites. Transformation rate and the type of metabolites that predominated in the culture medium and within the cells were significantly influenced by the culture conditions. The NAD(P)H-dependent enzymatic reduction of nitro-substituted compounds by cell-free extracts of R. terrigena was evaluated in vitro.
Cyclic voltammetry (CV) and preparative electrolysis techniques were used to investigate the reduction of nitrobenzene into (NB) p-aminophenol (p-Ap). The electrodes used in CV experiments were ...glassy carbon (GC), TiO2/Ti, Sn and Pb. The preparative electrolyses were carried out by the use of Pb, Sn, carbon cloth and TiO2/Ti electrodes. The CV data were evaluated according to Nicholson-Shain criteria, and it was deduced that the reductions on TiO2/Ti and GC electrodes were irreversible and monitored by an electrochemical-chemical-electrochemical mechanism. No reduction peak was observed with Sn and Pb electrodes. Preparative electrolyses were carried out under current-controlled conditions in the presence and absence of solvent. The best yield of (p-Ap) was obtained with a circulating neat NB electrolysis system on a TiO2/Ti electrode.
The ion-transfers of sodium and potassium cations, facilitated by naptho-15-crown-5, N15C5, were studied at an interface between water and nitrobenzene using current-scan polarography. A ...polarographic wave caused by the facilitated transfer of sodium cation was observed under the condition that the concentration of sodium cation was much higher than that of N15C5, Na+_??_N15C5. It is inferred from an analysis of the wave that a sodium cation trasfer is facilitated due to the formation of a 1:1 complex of metal-to-ligand ratio, Na(N15C5)+. However, since no wave was observed under the condition N15C5_??_Na+, a 1:2 complex may not exist in this condition. On the other hand, since a clear facilitated wave of potassium cation was only obtained under the condition N15C5_??_K+, the transfer of a 1:2 complex, K(N15C5)2+, is inferred. Since an indistinct wave overlapped by an anodic final current rise in K+_??_N15C5 appeared, a small stability of a 1:1 complex, K(N15C5)+, is expected. Considering the EC mechanisms for those transfers, the stability constants of those complexes in the nitrobenzene phase were determined. The values are 5.0×106M-1 for Na(N15C5)+ and 6.0×108M-2 for K(N15C5)2+ These results are quite consistent with the results from a solvent extraction study of these complexes.
Zusammenfassung
Hintergrund und Ziel der Arbeit
Bestimmte Arbeitsplätze weisen eine Kombination von Schadstoffexposition und Kälte auf. Es gibt Hinweise, dass Nitrobenzol zelltoxisch ist. Ziel dieser ...Studie war es, die toxische Wirkung von Nitrobenzol auf Organe wie Leber, Niere, Nebenniere, Milz und Schilddrüse zu untersuchen.
Material und Methoden
Diese Experimente erfolgten an 24 geschlechtsreifen männlichen Ratten des Stammes WAG. Jeder Versuchsgruppe (2 × 6 Tiere) wurde insgesamt 30-mal Nitrobenzol (70 mg/kg des Tiergewichtes) an 5 Tagen pro Woche und 6 Wochen lang in den Magen eingeleitet. Die Tiere der Kontrollgruppe (2 × 6 Tiere) erhielten eine äquivalente Menge Aqua destillata. Die Tiere wurden für 4 h Temperaturen der thermischen Behaglichkeit (25 ± 2 °C) oder der Kälte (4 ± 2 °C) ausgesetzt. Nach einer 30-tägigen Rekonvaleszenzzeit wurden die Daten neu erhoben, um der Fragestellung der Reversibilität nachzugehen.
Ergebnisse
Die Nitrobenzolwirkung führte in beiden Versuchsgruppen zu strukturellen Veränderungen in den untersuchten Organen, die jedoch nur bei der Versuchsgruppe unter Kälte irreversibel und schwerwiegender waren. Beispielsweise fanden sich Hinweise auf eine akute Hepatitis, aktivierte Immunreaktionen in Milz und Schilddrüse und Glomerulonephritis.
Diskussion
Es konnte im Tierversuch eine verstärkte und irreversible ubiquitäre zelltoxische Wirkung von Nitrobenzol unter Kältebedingungen nachgewiesen werden. Somit können die histologisch untersuchten Organe als Zielorgane für die toxische Wirkung von Nitrobenzol betrachtet werden.
The reaction of acid fluorides with N-heterocyclic carbenes (NHCs) produces anhydrous acyl azolium fluorides. With appropriate selection of acid fluoride and NHC, these salts can be used for the room ...temperature SNAr fluorination of a variety of aryl chlorides and nitroarenes.
Cake-like anatase/rutile mixed phase TiO2 (A/R TiO2) was successfully prepared through pyrolyzation of metal-organic frameworks MIL-125. Its morphology, structure and photocatalytic performance for ...degradation of nitrobenzene under UV light irradiation were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, nitrogen adsorption-desorption isotherms, UV–Vis absorption spectroscopy, photocurrent and photoluminescence spectroscopy, respectively. The results show that the cake-like A/R TiO2 exhibits excellent photocatalytic performance with a maximum nitrobenzene degradation rate of 97% and corresponding mineralization rate of 77% at 100 min under UV light irradiation, which is better than those of cake-like rutile TiO2 and anatase TiO2. The improved photocatalytic performance is ascribed to the reduced electron-hole pair recombination in cake-like A/R TiO2.
•Photocatalysis is an environmental-friendly technology for nitrobenzene removal.•Cake-like anatase/rutile TiO2 is fabricated by pyrolyzing metal-organic frameworks.•It exhibits excellent photocatalytic performance in degradation of nitrobenzene.•A high degradation rate of 97% in 100 min is achieved under UV light irradiation.
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