Tandem dehalogenation–hydrogenation reaction of halogenoarenes as model substrates of endocrine disruptors in water: Rhodium nanoparticles in suspension vs. on silica support

Magnetically Recoverable Palladium(0) Nanocomposite Catalyst for Hydrogenation Reactions in Water

“…The reactivity of bromobenzene is lower than of the chloroarenes (Table 2, entry 7 vs. 2), as already reported. [49][50][51] This result could be explained by the lower electron affinity of Br (3.364 eV) than that of Cl (3.615 eV), which results in a less effective activation of the bromo reactant through surface s-complex formation. The additional presence of a second chloro group (Cl or Br) on the ring leads to a deactivating effect, lowering the halogenoarene reactivity because the halogen substitution reduces the electron density associated with the ring carbons (entries 8-9).…”

“…This result was attributed to the production of chlorine species in the reaction mixture, which acts as a poison towards the catalytic system, as already reported. [48][49] The addition of chlorohydric acid hydrochloric acid in the hydrogenation of 1-tetradecene in n-hexane after 5 min led to deactivation of the catalyst, with a 40 % conversion after 2 h, instead of a complete transformation under classical conditions (Table 1, entry 2). Moreover, the maghemite (gFe 2 O 3 ) support was totally inactive towards the dechlorination reaction of 2-chloroanisole in water ( Table 2, entry 5), with no production of anisole after 24 h. In a second set of experiments, the scope of the reaction was extended to other halogenoarenes in neat water ( Table 2, entries 7-9).…”

Chiral Ammonium‐Capped Rhodium(0) Nanocatalysts: Synthesis, Characterization, and Advances in Asymmetric Hydrogenation in Neat Water

“…[34] Cinchona-based ammonium derivatives in the bromide and lactate series led to a higher cis-product ratio of around 70 % under hydrogen pressure compared with chiral skeletons based on N-methylephedrine or N-methylprolinol (Table 5, (Table 5, entries 1-4). Moreover, in a few cases, small traces of methylcyclohexanone were detected, as reported for the hydrogenation of anisole derivatives with nanocatalysts in solution [15b] or on supports, [35] but the formation of significant amounts of byproducts, such as partially reduced or hydrogenolysis compounds, was not observed. Finally, the structures of the salts do not seem to have an effect on the reaction enantioselectivity and no ee was obtained.…”

Efficient catalytic ozonation by ruthenium nanoparticles supported on SiO 2 or TiO 2 : Towards the use of a non-woven fiber paper as original support

“…Three different supports were used for the heterogeneization of Ru (0) The Ru(0) nanospecies were deposited on these various supports through a wet impregnation methodology, already reported in the literature [25,26,29]. First, 100 mL of an aqueous suspension of ruthenium NPs was prepared by reducing ruthenium chloride precursor (3.8 x 10 -4 mol RuCl 3 .…”