Polymer-Supported N-Hydroxyphthalimide as Catalyst for Toluene and p-Methoxytoluene Aerobic Oxidation

N-Hydroxyphthalimide Immobilized on Poly(HEA-co-DVB) as Catalyst for Aerobic Oxidation Processes

“…In this paper, the application of poly(HEA-co-DVB) as support for NHPI has been reported for the first time. In contrary to previously reported the polystyrene-supported NHPI [22] and GMA/MMA-supported NHPI [23], the new catalyst HEA/DVB-NHPI is characterized by higher NHPI loading. The formed linker is longer than in polystyrene and similar to GMA/MMA supported N-OH groups.…”

“…The pendant functional groups are used for the formation of stable covalent bonds with molecules of a catalyst. The pendant functional groups in commercially available polystyrenes, such as NH 2 and OH, have been previously used by us to immobilize trimellitic anhydride acid chloride (TAC), which is the precursor of NHPI [22]. Nevertheless, commercially available polymers contain only small amount of these functional groups.…”

“…These catalytic systems are especially attractive due to simple separation from the reaction mixture. Examples of heterogeneous NHPI catalysts include NHPI immobilized on silica gel by physical interaction [19], NHPI immobilized by chemical bonds on silica gel [20,21], polystyrene [22], copolymer microspheres of glycidyl and methyl methacrylate (GMA/MMA) [23] or glycidoxypropyl-SBA-15 [24] and NHPI incorporated into metal organic framework [25][26][27][28][29]. On the other hand, silica supported cobalt(II) [30,31], cobalt and manganese supported hexagonal mesoporous silicas [32] or cobalt Shiff base complex anchored on starch-coated magnetic nanoparticles [33] were also examined in the presence of homogeneous NHPI.…”

“…On the other hand, silica supported cobalt(II) [30,31], cobalt and manganese supported hexagonal mesoporous silicas [32] or cobalt Shiff base complex anchored on starch-coated magnetic nanoparticles [33] were also examined in the presence of homogeneous NHPI. The activity of these catalytic systems was demonstrated in aerobic oxidations of cyclohexane and other cyclic hydrocarbons [19,25,[27][28][29]32], toluenes [20][21][22]24], ethylbenzenes [23,25,30,31,33], styrenes [26] as well as other alkyl aromatic compounds [29,31,33] and benzylic alcohols [33]. For example, when toluene was oxidized with oxygen in the presence of both NHPI and Co(II) chemically bonded to silica gel in AcOH as solvent, conversion of 18 % was achieved (100 °C, 0.1 MPa, 20 h) [20].…”

“…Similar conversion was obtained when toluene was oxidized under pressure of oxygen in the presence of N,Ndihydroxypyromellitimide (NDHPI) supported on glycidoxypropyl-SBA-15 in MeCN (Co(II), 70 °C, 1.6 MPa, 7 h) [24]. When NHPI immobilized on commercial polystyrene via amide or ester bonds was applied in p-methoxytoluene oxidation with oxygen in AcOH or solvent-free condition conversions of 18 and 2.3 %, respectively, were achieved (Co(II), 80 °C, 0.1 MPa, 6 h) [22]. The final effect of NHPI immobilization on a solid carrier by means of covalent bond depends on quantity, quality and distribution of functional groups in a carrier.…”