Allylic oxidation of olefins to the corresponding α,β-unsaturated ketones catalyzed by chromium aluminophosphate-5

Supported Gold Nanoparticles Catalysts for Solvent-free Selective Oxidation of Benzylic Compounds into Ketones at 1 atm O2

“…1-indanol (1-InOl) (Scheme 1) [8]. It can be seen from Table 2 that without catalyst, the conversion was only 5% and 1-indan hydroperoxide was the major product (entry 1).…”

“…Meanwhile, diphenylmethane was oxidized with 25% conversion 95% selectivity of benzophenone (entry 5). Alkylbenzenes (C 2 to C 4 ) were oxidized to their corresponding phenones with poor yields (entries [6][7][8]. For instance, ethylbenzene and propylbenzene gave 26 and 18% of conversion and 85 and 90% selectivity of acetophenone and propiophenone, respectively.…”

“…Reaction products were also identified by GC-MS (Varian CP 3800, 1200L Quadrupole MS/MS, column: HP-1). It is known that alkyl hydroperoxide is the initial intermediate of the oxidation of benzylic compounds [8]. However, its yield cannot be measured directly by GC analysis because of its thermolability.…”

“…Yet, excessive use of these reagents, along with difficult work-up of the hazardous metal residues and lack of recyclability of homogeneous catalytic systems makes such procedures environmentally objectionable. As a consequence, many effective and recyclable transition metal based heterogeneous catalytic systems have been studied for the liquid phase oxidation of benzylic compounds [7][8][9][10][11]. However, these catalytic systems are generally performed in volatile and/or toxic organic solvents such as dichloromethane [7], chlorobenzene [8,10,11], methanol [9] etc., in combination with hydroperoxidebased oxidants and are often prone to leaching of metal ions leading to homogeneous processes.…”

“…Reaction conditions: m(substrate) = 1 g; m(Au/TiO 2 ) = 50 mg; t = 24 h; entries (1-4,6,7), T = 90°C; entries(5,8),…”