A Complexation Promoted Organic N‐Hydroxy Catalytic System for Selective Oxidation of Toluene

Abstract

Complexation was innovatively utilized to design a novel catalytic system for the selective oxidation of toluene, which runs contrary to the traditional definition of organic metal complex catalysis. In the present system, an N-heteroaromatic ringcontaining N-hydroxy compound acts as the catalytically active component. Through an electron-withdrawing effect produced by the occurring complexation with proper metal salts, which was characterized by real-time in situ Fourier transform infrared spectra, the activity of the organic molecule could be remarkably improved. The combination of copper(II) chloride with 6-hydroxy-pyrroloA C H T U N G T R E N N U N G [3,4-b]pyrazine-5,7-dione showed the best activity, and an inert hydrocarbon such as toluene could be efficiently transformed with 70.9% conversion and 93.5% selectivity to benzoic acid at 90 8C within 2 h.

Hydrogen Atom Transfer (HAT) Processes Promoted by the Quinolinimide-N-oxyl Radical. A Kinetic and Theoretical Study

“…NHQI was synthesized by reaction of pyridine-2,3-dicarboxylic acid anhydride 37 with hydroxylamine hydrochloride following a procedure reported in the literature. 10 Toluene, ethylbenzene, cumene, p-xylene, p-methoxytoluene, miodotoluene, 4-methylacetophenone, p-tolunitrile, cyclohexane, adamantane, methanol, ethanol, 2-propanol, tetrahydrofuran, N,Ndimethylformamide, and p-chlorobenzaldehyde were commercially available at their highest purity and used as received.…”

“…Via this connection, Xia et al showed that the catalytic activity of NHQI in the aerobic oxidation of toluene is significantly higher than that of NHPI either in the absence or in the presence of a metal cocatalyst. 10 More recently, it was reported that NHQI, in combination with 4-carboxyl-N-hydroxyphthalimide, showed excellent activity in the aerobic oxidation of ethylbenzene. 11 In this study, we report the ultraviolet−visible (UV−vis) and electron paramagnetic resonance (EPR) spectroscopic characterization of QINO and a kinetic investigation of the HAT reactivity of QINO with a series of organic substrates, including aliphatic hydrocarbons, alkylaromatics, alcohols, ethers, aldehydes, and amides.…”

Remarkable Effect of PEG-1000-based Dicationic Ionic Liquid for N-hydroxyphthalimide-catalyzed Aerobic Selective Oxidation of Alkylaromatics

“…3) led to a slightly lower conversion with comparable selectivity toward the formation of BAC (Run 5 and 6). When both Co(OAc) 2 and Mn(OAc) 2 were used, 15 the conversion increased but the selectivity for BAC was slightly decreased (Run 7).…”

“…In contrast to the traditional NHPI/Co(OAc) 2 6 11 were also tested, however, poor conversions were observed (Run 15 and 16). The reaction in PEG 1000 -DIL (PEG 1000-based dicationic ionic liquid) resulted in slightly lower conversion and selectivity due to its lack of acidity (Run 17).…”

“…1 The success of these oxygenations always depends largely on the development of catalysts to promote productivity, the rate of reaction, as well as the selectivity of products. 2 In recent years, due to its highly catalytic efficiencies even under mild conditions for the aerobic oxidation of various organic compounds in the presence of some metallic compounds or non-metallic compounds, Nhydroxyphthalimide (NHPI) is attracting continuous attention. 3−6 However, the progress of using NHPI suffers from difficulties encountered in the reuse of catalyst for new reactions 7 and employed corrosive acetic acid.…”