Hydroperoxidation of Tertiary Alkylaromatics Catalyzed By N‐Hydroxyphthalimide and Aldehydes under Mild Conditions

Abstract

A metal-free catalytic system consisting of an aldehyde and N-hydroxyphthalimide (NHPI) for the selective oxidation of tertiary alkylaromatics with molecular oxygen has been developed. Cumene was oxidized efficiently to the corresponding hydroperoxide under mild conditions. The molecule-induced homolysis between peracids generated in situ and NHPI ensured the formation of the phthalimide N-oxyl (PINO) radical even at room temperature. Investigations on aldehyde, solvent and temperature effects allowed us to achieve good conversions with high selectivity in hydroperoxide. The optimized procedure was successfully extended to phenylcyclohexane, a valuable alternative for the production of phenol. The mechanism is discussed in detail

Aerobic oxidation of isopropylaromatic hydrocarbons to hydroperoxides catalyzed by N-hydroxyphthalimide

“…The hydroperoxide in cumene oxidation reaction catalyzed by NHPI/CH 3 CHO system under moderate conditions at 25°C was obtained with a yield of approximately 50 % [13]. In contrast, the products of the oxidation of isopropylaromatic hydrocarbon catalyzed by NHPI and variable-valence metal salt systems primarily contained the corresponding alcohols and ketones [14][15][16][17].…”

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

“…1 H NMR (500 MHz) and 13 C NMR (125 MHz) were recorded on a Bruker 500 spectrometer using D 2 O as the solvent with tetramethylsilane (TMS) as an internal standard. IR spectra were recorded on a Bruker Vector 22 infrared spectrometer, as KBr pellets with absorption in cm −1 .…”

“…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.…”

Aerobic Oxidation of Alkylaromatics using a Lipophilic N‐Hydroxyphthalimide: Overcoming the Industrial Limit of Catalyst Solubility

“…According to our previous works, [18,19] this temperature could be considered as a good compromise of the need to obtain significant energy savings, good process yields with the reduced formation of byproducts, and the importance of preserving the catalyst from decomposition. Table 3 reports the maximum HC/ACN ratio (v/v) at which 1 (1 or 2 mol % with respect to the HC) could be found completely in solution.…”

“…[18,19] Aldehydes may generate PINO radicals, even at room temperature, through the formation of the corresponding peracetic acid under an oxygen atmosphere and consequent molecule-induced homolysis with 1 (Scheme 3). [37][38][39] In line with our previous works, we decided to perform the oxidation of CU, EtB, and CHB by using propionaldehyde as the initiator and comparing the performances of 1 and 3 at 70 8C.…”