Nitrobenzene

About: Nitrobenzene is a research topic. Over the lifetime, 5285 publications have been published within this topic receiving 83368 citations. The topic is also known as: essence of mirbane & nitrobenzol.

Reversible anion radical–dianion redox equilibria involving ions of simple aromatic compounds

Abstract: Anthracene, benzophenone, nitrobenzene, and several other simple aromatic compounds undergo two consecutive reversible one-electron transfers to give first the anion radical and then the dianion, both species being stable during the time scale of cyclic voltammetry in several electrophile-free solvents.

Cu/CuxO and Pt nanoparticles supported on multi-walled carbon nanotubes as electrocatalysts for the reduction of nitrobenzene

Abstract: Cu/CuxO and Pt nanoparticles supported on multi-walled carbon nanotubes (MWCNTs) were studied as electrocatalysts for the reduction of nitrobenzene in a half-cell set-up. This reaction not only produces valuable chemicals, but has the potential to generate electricity if applied in a fuel cell device. MWCNTs with and without functional groups were investigated as supports for the nanoparticles, employing either ethylene glycol (EG) or H2 gas as reductant. Cu/CuxO nanoparticles supported on pristine multi-walled carbon nanotubes prepared using H2 as reductant (Cu/MWCNT-H2) were identified as the best electrocatalyst for the reduction of nitrobenzene on the basis of its onset potential and of the number of electrons transferred per nitrobenzene molecule. This material consists of well-dispersed Cu/CuxO nanoparticles with an average size of 8 nm. The stability of Cu/MWCNT-H2 was tested by cyclic voltammetry (CV) for 1000 cycles, showing that the activity of this electrocatalyst does not deteriorate over time. The electrochemical reduction of nitrobenzene over Cu/MWCNT-H2 in acidic ethanolic medium at −0.62 V vs. Fc/Fc+ led to 44% conversion with an overall selectivity toward azoxybenzene (AOB) of 82%.

Gas-phase reaction of OH radicals with benzene: products and mechanism

Abstract: The gas-phase reaction of OH radicals with benzene was studied in O2/He mixtures under flow conditions in the temperature range 276–353 K and at pressures of 100 and 500 mbar using on-line FT-IR spectroscopy and GC-MS measurements. The reaction conditions were chosen so that the initially formed OH/benzene adduct predominantly reacted either with O2 or O3. Under conditions of a predominant reaction of the OH/benzene adduct with O2 the product formation was studied for variable NO concentrations. Identified products were the isomers of hexa-2,4-dienedial, phenol, nitrobenzene, p-benzoquinone and glyoxal. Furan was found in small amounts. For increasing NO concentrations there was a decrease of the phenol yield and the yields of trans,trans-hexa-2,4-dienedial and nitrobenzene increased, resulting in maximum values of 0.36 ± 0.02 and 0.11 ± 0.02, respectively (100 mbar, 295 K). The p-benzoquinone yield of 0.08 ± 0.02 was found to be independent of the NO concentration. The temperature dependence of the phenol yield was measured in the range of 276–353 K for initial ratios of [NO]/[O2] = 1–20 × 10−6 at 500 mbar. For a fixed [NO]/[O2] ratio, a distinct increase of the phenol yield with increasing temperature was observed; initial [NO]/[O2] = 1–1.2 × 10−6, phenol yield: 0.18 ± 0.04 (276 K) and 0.68 ± 0.05 (353 K). Generally, the total yield of carbonylic substances was found to be anti-correlated to the phenol yield. When the OH/benzene adduct reacted with O3, trans,trans-hexa-2,4-dienedial, phenol and formic acid were identified as main products with formation yields of 0.28 ± 0.02, 0.20 ± 0.05 and 0.12 ± 0.02, respectively (100 mbar, 295 K). Further products were p-benzoquinone, CO and unidentified carbonylic substances. For the different experimental conditions, reaction mechanisms are proposed explaining the formation of the observed products. A simple model describing the temperature and NOx-dependence of the phenol yield is presented.