Main content area

N-Methylation of amines and nitroarenes with methanol using heterogeneous platinum catalysts

Jamil, Md.A.R., Touchy, Abeda S., Rashed, Md. Nurnobi, Ting, Kah Wei, Siddiki, S.M.A. Hakim, Toyao, Takashi, Maeno, Zen, Shimizu, Ken-ichi
Journal of catalysis 2019 v.371 pp. 47-56
aromatic amines, catalysts, density functional theory, hydrogen, methanol, nanoparticles, platinum
We report herein the selective N-methylation of amines and nitroarenes with methanol under basic conditions using carbon-supported Pt nanoparticles (Pt/C) as a heterogeneous catalyst. This method is widely applicable to four types of N-methylation reactions: (1) N,N-dimethylation of aliphatic amines under N2, (2) N-monomethylation of aliphatic amines under 40 bar H2, (3) N-monomethylation of aromatic amines under N2, and (4) tandem synthesis of N-methyl anilines from nitroarenes and methanol under 2 bar H2. All these reactions under the same catalytic system showed high yields of the corresponding methylamines for a wide range of substrates, high turnover number (TON), and good catalyst reusability. Mechanistic studies suggested that the reaction proceeded via a borrowing hydrogen methodology. Kinetic results combined with density functional theory (DFT) calculations revealed that the high performance of Pt/C was ascribed to the moderate metal–hydrogen bond strength of Pt.