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.

Aggregation of asphaltenes obtained from a brazilian crude oil in aromatic solvents

Abstract: Surface and interfacial tensions in model systems formed by a Brazilian crude oil n-pentane insolubles (C5I) and n-heptane insolubles (C7I) in three different aromatic solvents: toluene, pyridine and nitrobenzene, were measured at room temperature, employing an automatic tensiometer and using the ring method. The results obtained indicated possible asphaltene aggregation and allowed the determination of critical micelle concentrations (c.m.c) for both C5I and C7I fractions in each of the three solvents considered. In toluene and pyridine solutions, the C5I fraction consistently presented higher c.m.c. values indicating a lower tendency of association for the organic fraction contained in the C5I, and absent in the C7I. In nitrobenzene solutions, this extra organic fraction appears to facilitate asphaltene association, possibly due to the formation of mixed aggregates. Average molecular areas for asphaltenes adsorbed at different interfaces were estimated using measured tensions and found to be in...

Low-temperature phase separation of a binary liquid mixture in porous materials studied by cryoporometry and pulsed-field-gradient NMR.

Abstract: The low-temperature liquid-liquid phase separation of the partially miscible hexane-nitrobenzene mixture imbibed in porous glasses of different pore sizes from 7 to 130 nm has been studied using 1H NMR (nuclear magnetic resonance) cryoporometry and pulse field gradient NMR methods. The mixture was quenched below both its upper critical solution temperature (T(cr)) and the freezing point of nitrobenzene. The size distribution of frozen nitrobenzene domains was derived through their melting point suppression according to the Gibbs-Thompson relation. The obtained data reveal small initial droplets of nitrobenzene surrounded by hexane, which are created as the temperature is decreased below T(cr) and which thereafter coalesce by a droplet-diffusion mechanism. The inter-relation between the pore size and the found size distribution and shapes of nitrobenzene domains is discussed, as well as several aspects of molecular self-diffusion.

Insights into Different Products of Nitrosobenzene and Nitrobenzene Hydrogenation on Pd(111) under Realistic Reaction Conditions

Abstract: Selective hydrogenation of nitroarene compounds is applied in many fields such as agrochemicals, pharmaceuticals, and dyes. Pd-catalyzed hydrogenation of nitrobenzene (PhNO2) and nitrosobenzene (PhNO) could exhibit different selectivities. This was regarded as the evidence to challenge the Haber mechanism for PhNO2 hydrogenation in which PhNO is an important intermediate. In this study, we systematically investigate their hydrogenation mechanisms under realistic reaction conditions based on first-principles calculations. It is found that the weak bonding between the nitro group and the Pd(111) surface leads to the flat-lying chemisorption configuration of PhNO2 and the other intermediates during PhNO2 hydrogenation. In contrast, the strong bonding between the nitroso group and the surface makes PhNO switch its chemisorption mode from flat-lying adsorption under the ultrahigh vacuum condition to vertical adsorption under reaction conditions. For the flat-lying PhNO2, the chemisorbed phenyl group makes hydr...

N-doped nanoporous carbon as efficient catalyst for nitrobenzene reduction in sulfide-containing aqueous solutions

Abstract: Metal-free N-doped porous carbon (NC) materials have been demonstrated to be promising catalysts in contaminated environment remediation. Two NC materials (NC-1 and NC-2) were prepared by sol-gel routes. Their catalytic properties were investigated for the reduction of nitrobenzene (NB) in sulfide-containing aqueous solution. Both NC-1 and NC-2 can efficiently catalyze the reduction of NB to aniline (AN) under ambient conditions, but also can be reused for more than 5 times. The reaction fits excellently to the pseudo-first-order kinetic. Compared with NC-1 material, NC-2 shows much higher removal efficiency (rate constant kobs: 0.283 h−1 vs. 2.50 h−1). The important features of NC material, including high specific surface area, suitable surface functional groups (especially nitrogen-containing groups), and enhanced electron transfer ability, should be mainly factors for its excellent catalytic activity. This work demonstrates that N-doped carbon materials have great potential for degradation of NB to AN in the natural aquatic environment.