Immobilization of Cobalt Phthalocyanine and Tetrasulfophthalocyanine onto MCM-41 and MCM-48: Effect of Immobilization Method on Catalytic Activity

Mahtab Pirouzmand,Nasser Safari,Mostafa M Amini,Touba Hamoule

doi:10.5935/0103-5053.20130233

Abstract

Cobalt tetrasulfophthalocyanine (CoPcS) was chemically anchored to amine-modified MCM-41 and MCM-48 surface. These mesoporous silica were prepared by hydrothermal procedure. Physical mixtures of CoPc in MCM-41 and in MCM-48 were also prepared for comparison purposes. The four prepared catalysts, 10 wt.% CoPcS/NH2-MCM-41, 10 wt.% CoPcS/NH2-MCM-48, 10 wt.% CoPc/MCM-41 and 10 wt.% CoPc/MCM-48, were characterized by X-ray diffractometry (XRD), diffuse reflectance UV-Vis spectroscopy and BET specific surface analysis. The catalytic activity of the immobilized catalysts was tested in the aerobic epoxidation of cyclohexene. CoPcS/NH2-MCM-41 and CoPcS/NH2-MCM-48 showed relatively high epoxide selectivity but low conversion of cyclohexene compared to CoPc/MCM-41 and CoPc/MCM-48. No leaching of metallophthalocyanine from the catalysts immobilized by chemical bonding into the reaction medium was observed and these catalysts could be reused four times.

Highlights

Molecular oxygen has been recently utilized as an attractive and environmentally benign oxidant for oxidation reactions because it is of easy accessibility, inexpensive and non-toxic
Mercaptant removal from the petroleum catalyzed by cobalt phthalocyanines, especially cobalt tetrasulfophthalocyanine (CoPcS), is one of the primary methods used for the deodoration of petroleum products (Merox process).[20]
The immobilization of cobalt tetrasulfophthalocyanine (CoPcS) complex on the inner surface of the pores of NH2-MCM-41 or NH2-MCM-48 occurs by means of chemical bonding with the amine groups

Summary

Introduction

Molecular oxygen has been recently utilized as an attractive and environmentally benign oxidant for oxidation reactions because it is of easy accessibility, inexpensive and non-toxic. Oxidation of cyclohexene with dioxygen in the presence of mesopore-encapsulated metallophthalocyanines as Immobilization of Cobalt Phthalocyanine and Tetrasulfophthalocyanine onto MCM-41 and MCM-48 J. Using MCM-41 and MCM-48 as support, the CoPcS catalyst was immobilized by a multi-step grafting method.

Results

Conclusion