Synthesis of Supported Gold Nanocatalysts for the Oxidation of Alkyl Benzenes

摘要

Selective oxidation of alkyl benzene, to its corresponding oxygen containing products, is a crucial reaction in organic researches and industrial manufacturing. In particular, the direct oxidation of lavish and cheapest aromatics, having carbon-hydrogen bonds, into corresponding ketones are the key transformations as the oxidation products are very important platform compounds for the production of useful prime, special chemicals and high economic valued fine chemicals, agrochemicals, pharmaceutical and perfumes in large scale. However, the oxidations of aromatic hydrocarbons have been remaining a challenging task due to the limitations of a suitable catalyst and requirement of chemical treatments (potassium permanganate/dichromate and ammonium cerium nitrate) which have been proven to be corrosive, not reusable, hazardous, and environmentally unfriendly and, also, have no selectivity at all. Instead of, scientists are paying more attention to use heterogeneous green catalysts along with support as well as novel oxidants e.g. hydrogen peroxide, tert-butyl peroxide and so on, due to its ecofriendly nature and availability. Silica/carbon/metal oxide supported nanoporous gold is a favorable catalyst due to its three dimensional open pore network structures, high surface to volume ratio, high reusability, distinct optolectronic and physio-chemical properties. Mesoporous carbon/silica/metal oxide supports provide well scattering of metal nanocatalysts and facilitate the transportation of molecules through the nanopores/nanochannels, thus increase the product with lowest cost and time. This paper has reviewed various gold-skeleton green catalysts and their synthetic method and mechanistic schemes for the selective oxidation of alkyl substituted aromatics.