Premium
Oxidative Coupling of 2‐Methyl‐1‐naphthol: A Comparison between Bismuth‐Promoted Pt, Pd and Ag Catalysts
Author(s) -
Maphoru Mabuatsela V.,
Heveling Josef,
Kesavan Pillai Sreejarani
Publication year - 2018
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201801148
Subject(s) - catalysis , nitromethane , physisorption , solvent , oxidative coupling of methane , chemistry , yield (engineering) , bismuth , particle size , high resolution transmission electron microscopy , nuclear chemistry , coupling reaction , metal , noble metal , inorganic chemistry , materials science , organic chemistry , nanotechnology , metallurgy , transmission electron microscopy
Catalyst development for the oxidative coupling of naphthols is important for the synthesis of biomimetic compounds and pharmaceuticals. Carbon supported 5%M‐5%Bi catalysts (M=Pt, Pd, Ag) were prepared by electroless deposition. The resulting nanocomposites were characterized by N 2 physisorption, XRD, SEM, HRTEM, EDX and TGA. Narrow particle size distributions of the noble metals were obtained, corresponding to an average particle size of 3.1–3.2 nm. Oxidative coupling of 2‐methyl‐1‐naphthol with H 2 O 2 as the oxidant was the test reaction. The catalyst activities increase in the order Ag < Pd ≪ Pt. The outcome of the reaction depends on M, the solvent and the reaction temperature. Over Pt and Pd the binaphthol (3,3’‐dimethyl‐1,1’‐binaphthalenyl‐4,4’‐diol) can be obtained with yields of 89–94% in refluxing nitromethane. Under otherwise identical conditions, Ag gives the binaphthone (3,3’‐dimethyl‐1,1’‐binaphthalenylidene‐4,4’‐dione) with an isolated yield of 80%. The results show that apart from the solvent and the reaction temperature, also the choice of the catalytic metal can have an important influence on the outcome of the reaction.