Synthesis, Characterization, and Catalytic Activity of Metallo Octamethylcalix (4) Pyridino Complexes Encapsulated in MCM-41

Abstract

The synthesis and encapsulation of M⁺ⁿ-octamethylcalix(4)pyridino complexes using acetone and pyridine in H-MCM-41 have been achieved and presented. These hybrid catalysts are characterized by x-ray diffraction, infrared, thermal analysis, Brunauer–Emmett–Teller (BET) surface area, and scanning electron microscopy and tested for catalytic activity. They are active in the liquid-phase oxidation of p-xylene using H₂O₂ as oxidant and acetic acid as solvent in the temperature range of 30–100 °C. The variation of central transition-metal cation and the heterocyclic ring in the metallomacrocycle influence the catalytic activity.

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GRAPHICAL ABSTRACT

Keywords:

• Encapsulation
• MCM-41
• metallomacrocycles
• molecular sieves
• oxidation

Notes

^a Molar ratio = p-xylene/H₂O₂ = 1:4, solvent = AcOH, catalyst = Co-OMCPy-MCM-41 = 100 mg, time = 20 h, 4-methylbenzyl alcohol, 1,4-benzenedicarboxaldehyde, etc.

^a Molar ratio = p-xylene/H₂O₂ = 1:4, solvent = AcOH, catalyst = Co-OMCPy-MCM-41 = 100 mg, temp. = Room temp, 4-methylbenzyl alcohol, 1,4-benzenedicarboxaldehyde, etc.

^a Time = 20 h, temp. = room temp., solvent = AcOH, catalyst = Co-OMCPy-MCM-41 = 100 mg, 4-methylbenzyl alcohol, 1,4-benzenedicarboxaldehyde, etc.

^a Molar ratio = p-xylene/H₂O₂ = 1:4, catalyst = Co-OMCPy-MCM-41, temp. = room temp., Time = 20 h, 4-methylbenzyl alcohol, 1,4-benzenedicarboxaldehyde, etc.

^a Molar ratio = p-xylene/H₂O₂ = 1:4, solvent = AcOH, temp. = room temp., time = 20 h, catalyst = 100 mg, 4-methylbenzyl alcohol, 1,4-benzenedicarboxaldehyde, etc.

^a Molar ratio = p-xylene/H₂O₂ = 1:4, time = 20 h, 100 mg catalyst = Co-OMCPy-MCM-41, temp. = room temp.