A New Method for Immobilization of NDHPI on SBA-15 Carrier Used as Catalyst for Selective Oxidation of Toluene

Mesoporous molecular sieve SBA-15 immobilized N,N-dihydroxypyromellitimide (NDHPI) was prepared by a new method, which was realized through the coupling NDHPI with pre-grafted glycidoxypropyl chains of glycidoxypropyl-SBA-15. SBA-15 immobilized N-hydroxyphthalimide (NHPI) by impregnation method was also prepared for comparison. The two catalysts were characterized by Fourier transform infrared spectroscopy, N-2 adsorption-desorption technique, thermogravimetric analyses, X-ray diffraction, scanning electron microscope, transmission electron microscope and X-ray photoelectron spectroscopy. Then the catalysts and N,N-bis(salicylidene) ethylenediiminocobalt (Cosalen) complex were used into oxidation of toluene with molecular oxygen. The more active and reusable catalyst was the immobilized one coupled by NDHPI with glycidoxypropyl-SBA-15, which improved the total selectivity of benzaldehyde and benzyl alcohol to 46.0 % with the conversion of toluene 14.8 % at 90 A degrees C for 7 h. Mesoporous molecular sieve SBA-15 immobilized N,N-dihydroxypyromellitimide (NDHPI) was prepared by a new method, which was realized through the coupling NDHPI with pre-grafted glycidoxypropyl chains of glycidoxypropyl-SBA-15. SBA-15 immobilized NHPI by impregnation method was also prepared for comparison. Their structure was characterized and their catalytic performance combined with Cosalen complex in the molecule oxidation of toluene were compared. Their reusability performance was also discussed. [GRAPHICS]