title: Doped graphene as a metal-free carbocatalyst for the selective aerobic oxidation of benzylic hydrocarbons, cyclooctane and styrene.
abstract: Nitrogen (N)-, boron (B)-, and boron,nitrogen (B,N)-doped graphene (G) act as carbocatalysts, promoting the aerobic oxidation of the benzylic positions of aromatic hydrocarbons and cyclooctane to the corresponding alcohol/ketone mixture with more than 90 % selectivity. The most active material was the co-doped (B,N)G, which, in the absence of solvent and with a substrate/(B,N)G ratio of 200, achieved 50 % tetralin conversion in 24 h with a alcohol/ketone selectivity of 80 %. An FT-Raman spectroscopic study of a sample of (B,N)G heated at 100 °C in the presence of oxygen revealed new bands that disappeared upon evacuation and that have been attributed to hydroperoxide-like species formed on the G sheet based on the isotopic shift of the peak from 819 to 779 cm(-1) when (18)O2 was used as the oxidizing reagent. Furthermore, (B)G and (N)G exhibited high catalytic activity in the aerobic oxidation of styrene to benzaldehyde (BA) in 4 h. However, the product distribution changed over time and after 10 h a significant percentage of styrene oxide (SO) was observed under the same conditions. The use of doped G as catalyst appears to offer broad scope for the aerobic oxidation of benzylic compounds and styrene, for which low catalyst loading, mild reaction temperatures, and no additional solvents are required.
authors.affiliation: Departamento de Química, Univ. Politécnica de Valencia, Av. De los Naranjos s/n, 46022 Valencia, Spain.
authors.forename: Amarajothi
authors.initials: A
authors.lastname: Dhakshinamoorthy
authors.forename: Ana
authors.initials: A
authors.lastname: Primo
authors.forename: Patricia
authors.initials: P
authors.lastname: Concepcion
authors.forename: Mercedes
authors.initials: M
authors.lastname: Alvaro
authors.forename: Hermenegildo
authors.initials: H
authors.lastname: Garcia