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.

Vapor phase nitration of benzene over solid acid catalysts: III. Nitration with nitric acid (2); mixed metal oxide treated with sulfuric acid and heteropolyacid partially neutralized

Abstract: Vapor phase nitration of benzene over solid acid catalysts is expected to be a clean process without sulfuric acid waste. In this research we investigated the vapor phase nitration of benzene by dilute nitric acid. We found that the catalytic activity of mixed metal oxides containing TiO2 or ZrO2 was improved greatly by the treatment with sulfuric acid at 500°C and that the catalytic activity of heteropolyacid can be increased greatly by partial neutralization with Cs or Tl. The reasons for these enhancements were identified as the increase of acid strength and the active surface area, respectively. The catalytic activity is very stable, especially for the mixed oxide treated with sulfuric acid. The TiO2(4)–MoO2(1) after treatment with sulfuric acid at 500°C showed a high activity: 87% yield of nitrobenzene (STY=0.72 kg/kg cat h) for more than 528 h on stream.

Contribution to the Thermodynamics of Complexes of Alkali Metal Cations with Benzo-18-Crown-6 in the Water–Nitrobenzene Extraction System

Abstract: From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+(aq) + NaL+(nb) ⇔ ML+(nb) + Na+(aq) taking place in the two–phase water–nitrobenzene system (M+ = Li+, K+, Rb+, Cs+; L = benzo-18-crown-6; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Further, the stability constants of the ML+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order Cs+ < Rb+ < Li+ < Na+ < K+.

Linear, Single-Strand Heteroaromatic Polymers from Superacid-Catalyzed Step-Growth Polymerization of Ketones with Bisphenols

Abstract: Novel, linear, high-molecular-weight single-strand heteroaromatic polymers and copolymers containing 9H-xanthene moieties in the backbone were synthesized by metal-free superacid-catalyzed stoichiometric and nonstoichiometric step-growth polymerizations of carbonyl compounds bearing electron-withdrawing substituents with bisphenols. The electrophilic aromatic substitution reactions of ketones with phenol fragments occur exclusively in ortho-positions to the hydroxy phenol group and followed by highly efficient cyclodehydration reaction of hydroxyl-containing intermediates to give corresponding substituted 9H-xanthene-2,7-diyl polymers. The polymerizations were performed at room temperature in the Bronsted superacid trifluoromethanesulfonic acid (CF3SO3H, TFSA) and in a mixture of TFSA with methylene chloride and nitrobenzene.

A new method based on headspace adsorptive accumulation using a carboxylated multi-walled carbon nanotubes modified electrode: application for trace determination of nitrobenzene and nitrotoluene in water and wastewater

Abstract: A carboxylated multi-walled carbon nanotubes modified glassy carbon (MWCNTs-GC) electrode was fabricated via the drop-casting of a carboxylated carbon nanotubes suspension onto a glassy carbon electrode. A headspace adsorptive accumulation on the surface of the multi-walled carbon nanotubes modified glassy carbon electrode coupled with cyclic voltammetry has been established for analyzing nitrobenzene and 4-nitrotoluene in water samples. Factors which affect the extraction efficiency (modifier amount, pH, extraction temperature, extraction time, salt addition) have been investigated. The calibration plot for the determination of nitrobenzene and 4-nitrotoluene are linear in the wide ranges of 10–4000 ng mL−1 and 20–6000 ng mL−1 respectively. Under optimal extraction conditions, the detection limits (at S/N = 3) for nitrobenzene and 4-nitrotoluene were 3.0 ng mL−1 and 6.0 ng mL−1 respectively. The proposed method has been applied successfully for the determination of nitrobenzene and nitrotoluene in water and wastewater samples within a recovery range of ca. 97.5–103.33%.