Aniline

Abstract: The properties of iron metal that make it useful in remediation of chlorinated solvents may also lead to reduction of other groundwater contaminants such as nitro aromatic compounds (NACs). Nitrobenzene is reduced by iron under anaerobic conditions to aniline with nitrosobenzene as an intermediate product. Coupling products such as azobenzene and azoxybenzene were not detected. First-order reduction rates are similar for nitrobenzene and nitrosobenzene, but aniline appearance occurs more slowly (typical pseudo-first-order rate constants 3.5 × 10-2, 3.4 × 10-2, and 8.8 × 10-3 min-1, respectively, in the presence of 33 g/L acid-washed, 18−20 mesh Fluka iron turnings). The nitro reduction rate increased linearly with concentration of iron surface area, giving a specific reaction rate constant (3.9 ± 0.2 × 10-2 min-1 m-2 L). The minimal effects of solution pH or ring substitution on nitro reduction rates, and the linear correlation between nitrobenzene reduction rate constants and the square-root of mixing ra...

Abstract: The selective formation of aromatic azo compounds at preparative or industrial levels requires stoichiometric amounts of environmentally unfriendly transition metals or nitrites. Here, we show that gold nanoparticles supported on titanium dioxide (TiO2) and nanoparticulated cerium dioxide (CeO2) catalyze the aerobic oxidation of aromatic anilines to aromatic azo compounds with yields above 98% under mild reaction conditions. Gold on TiO2 can also act as a reductive catalyst to access the compound directly from nitroaromatics through a two-step, one-pot reaction. The catalytic process shows promise for efficient synthesis of symmetric aromatic azo compounds, and even a range of asymmetric aromatic azo compounds.

Abstract: In experiments modeling the reactions of the reductive acetyl–coenzyme A pathway at hydrothermal temperatures, it was found that an aqueous slurry of coprecipitated NiS and FeS converted CO and CH 3 SH into the activated thioester CH 3 -CO-SCH 3 , which hydrolyzed to acetic acid. In the presence of aniline, acetanilide was formed. When NiS-FeS was modified with catalytic amounts of selenium, acetic acid and CH 3 SH were formed from CO and H 2 S alone. The reaction can be considered as the primordial initiation reaction for a chemoautotrophic origin of life.

Abstract: Phenols are widely used as starting materials in both industrial and academic society. Dearomatization reactions of phenols provide an efficient way to construct highly functionalized cyclohexadienones. The main challenge to make them asymmetric by catalytic methods is to control the selectivity while overcoming the loss of aromaticity. In this tutorial review, an up to date summary of recent progress in CADA reactions of phenol and aniline derivatives is presented.