Cu2+-phthalocyanine and Co2+-perfluorophthalocyanine incorporated inside Yfaujasite and mesoporous MCM-41 as heterogeneous catalysts for the oxidation of cyclohexane

A series of Cu2+-phthalocyanine and Co2+-perfluorophthalocyanine has been p repared inside the pores of MCM-41 (MPcMCM-41) by synthesis from o-dicyanob enzene. The complexes were characterized by comparison of the W-Vis diffuse reflectance and IR spectra with that of the same unsupported complexes. Tr ansition metal ion exchange levels higher than 40% were found necessary for the success of the synthesis, o-Cyanobenzoic acid and phthalic anhydride w ere isolated as byproducts, Differential scanning calorimetry indicates tha t the complexes are more stabilized inside MCM-41 than within the supercage s of Y faujasite. This has been interpreted as a reflection of the differen t conformations (planar for MCM-41 and distorted for Y faujasite) depending on the pore size of the host. The catalytic performance of novel MPcMCM-41 for cyclohexane oxidation was compared with that of the same unsupported c omplexes or when encaged within Y faujasite, tert-Butyl hydroperoxide was f ound as a more convenient oxidizing reagent than hydrogen peroxide. No leac hing of the MPc or uncomplexed metal ions was observed. It was found that C oF16PcMCM-41 was more active and selective than CoF16PcY or unsupported COF 16PC However, in the case of the CuPc complex, the highest activity and sel ectivity was achieved using CuPcY. Our work shows the influence that the vo id dimensions of the porous host can play in the performance of metallophth alocyanines as oxidation catalysts. (C) 1999 Elsevier Science B.V. All righ ts reserved.