Synthesis and characterization of a new epoxidation catalyst by grafting cis-MoO 2(salpr) complex to functionalized MCM-41

Abstract

The mesoporous molecular sieve MCM-41 was covalently grafted with 3-chloropropyl trimethoxylsilane and was then reacted with N, N′-bis(3-salicylidenaminopropyl)amine(salpr) to afford MCM-41 containing salpr ligand, salpr/Si-MCM-41. Powder X-ray diffraction and nitrogen adsorption–desorption analyses revealed that not only the textural characteristics of the support were preserved during the grafting experiments but also the channels remained accessible despite sequential reduction in surface area, pore volume and pore size. The salpr/Si-MCM-41 material was then reacted with MoO 2(acac) 2 to give MoO 2(salpr)/Si-MCM-41 catalyst with molybdenum loading of 1.75 wt.%. The molybdenum-containing MCM-41 was shown to successfully catalyze the epoxidation of 1-hexene, 1-octene, cyclohexene and cyclooctene with tert-butylhydroperoxide (TBHP) quantitatively with 95–99% selectivity toward the corresponding epoxides under mild conditions.