Synergistic Catalytic Oxidation of Ethylbenzene to Acetophenone by Metallophthalocyanine Intercalated Layered Double Hydroxide with Oxygen

Abstract

The organic‐inorganic hybrid material originated from metallophthalocyanine and layered double hydroxide has been identified as bifunctional catalyst for the oxidation of ethylbenzene to acetophenone. The hybrids exhibited excellent catalytic activity in the selective oxidation through O2/NHPI (N‐hydroxyphthalimide) system with excellent selectivity of acetophenone. The hybrid could accelerate not only the formation of hydroperoxide, but also the decomposition of hydroperoxide. Further, the catalyst also exhibited high activity in the transformation of 1‐phenylethanol to acetophenone. The present catalytic system could also catalyze the aerobic oxidation of varied alkyl arenes under the optimized reaction conditions. A series of controlled experiments suggested that the basicity of the hybrid benefited for the catalytic activity, and synergistic effect might exist between the basicity and the activity of metallophthalocyanine during the oxidation. On the basis of obtained results and Hammett experiment, a possible mechanism of the oxidation of ethylbenzene under the hybrid in the presence O2/NHPI has been proposed.

Zeolitic Imidazolate Framework-Mediated Synthesis of Co3O4 Nanoparticles Encapsulated in N-Doped Graphitic Carbon as an Efficient Catalyst for Selective Oxidation of Hydrocarbons

“…Raising the temperature (160 o C) favours for the production of higher amount of oxygen radicals which caused considerable enhancement in conversion but the reduces the selectivity of acetophenone due to over oxidation. 57 Nevertheless, with further increase of reaction time at 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 25 corresponding oxidation products at moderate conversions ( Table 3, entry 3). Comparison of conversion rate for the tetralin and indane, among these indane has shown high catalytic oxidation to respected oxidized products due to C-H low bond dissociation energy (82.9 K cal /mole) and high strained C-H bond compared to the tetralin molecule, further confirming the broader applicability of our catalysts for the selective oxidation of saturated C-H bonds.…”

Metallophthalocyanines as Catalysts in Aerobic Oxidation

“…A plausible mechanism for this catalytic process was proposed, which involved deprotonation and radical pathways. Chen and collaborators [79] found that the hybrid materials M(II)Pc(SO3 -)4@-Zn2Al-LDH (M = Co(II), Cu(II), Mn(II), and Fe(II)), obtained from the coprecipitation method of the metal complexes of the anionic tetrasulfonic phthalocyanine M(II)Pc(SO3H)4 (Figure 17) with zinc and aluminum layered double hydroxides (LDHs) showed an excellent catalytic performance in the oxidation of different olefins in the presence of O2/isobutyraldehyde, IBA [80] and are also efficient catalysts for the selective oxidation of ethylbenzene to acetophenone in the presence of O2/NHPI (N-hydroxyphthalimide), using benzonitrile as solvent at 120 °C. The best results were observed for the hybrid M = Co(II) (90% of conversion and selectivity higher than 99%) with no appreciable reduction on its activity or selectivity even after five runs.…”

“…Under the optimized reaction conditions, M(II)Pc(SO3 − )4@-Zn2Al-LDH was also able to catalyze the aerobic oxidation of other alkyl arenes (Table 4) and a series of controlled experiments suggested that a synergistic effect might exist between the basicity of the support and the activity of M(II)Pc during the oxidation. Chen and collaborators [79] found that the hybrid materials M(II)Pc(SO 3 − ) 4 @-Zn 2 Al-LDH (M = Co(II), Cu(II), Mn(II), and Fe(II)), obtained from the coprecipitation method of the metal complexes of the anionic tetrasulfonic phthalocyanine M(II)Pc(SO 3 H) 4 (Figure 17) with zinc and aluminum layered double hydroxides (LDHs) showed an excellent catalytic performance in the oxidation of different olefins in the presence of O 2 /isobutyraldehyde, IBA [80] and are also efficient catalysts for the selective oxidation of ethylbenzene to acetophenone in the presence of O 2 /NHPI (N-hydroxyphthalimide), using benzonitrile as solvent at 120 • C. The best results were observed for the hybrid M = Co(II) (90% of conversion and selectivity higher than 99%) with no appreciable reduction on its activity or selectivity even after five runs. Under the optimized reaction conditions, M(II)Pc(SO 3 − ) 4 @-Zn 2 Al-LDH was also able to catalyze the aerobic oxidation of other alkyl arenes (Table 4) and a series of controlled experiments suggested that a synergistic effect might exist between the basicity of the support and the activity of M(II)Pc during the oxidation.…”

Full use of factors promoting catalytic performance of chitosan supported manganese porphyrin

“…immobilized metalloporphyrins and their catalysis systems [31][32][33][34][35] adapting to the cleaner production process. However, the resulting yields (acetophenone and phenylethanol (ONE + OL), less than 25%) were lower than those obtained from the catalytic systems above [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] . In addition, RSM was also seldom used in the catalytic field of metalloporphyrins [14][15][16][17]19,20,[31][32][33][34][35] .…”