Promoting the selective catalytic oxidation of diethylamine over MnOx/ZSM-5 by surface acid centers

Herein, we demonstrated the selective catalytic oxidation of diethylamine to N-2 over MnOx/ZSM-5 catalysts. It was found that oxidation activity of diethylamine over MnOx/ZSM-5 catalysts increased when the loading of Mn increased, but the N-2 selectivity decreased at 420 degrees C obviously. MnO x /ZSM-5(360) catalysts showed higher oxidation activity of diethylamine than MnOx/ZSM-5(18) catalysts with equivalent Mn loading, which was as- cribed to the presence of MnO x species easily reduced and enriched on ZSM-5(360) support surface. However, MnOx/ZSM-5(18) catalysts containing moderate and strong surface acid centers in addition to the weak acid centers gave signi ficantly higher N-2 selectivity than MnOx/ZSM-5(360) catalysts possessing only weak surface acid centers. 20MnO(x)/ZSM-5(18) catalyst had relatively high oxidation activity of diethylamine and N-2 se- lectivity, of which the lowest reaction temperature for diethylamine conversion at 98% (T 98 ) is 240 degrees C and the N-2 selectivity is exceeding 95.5% at 420 degrees C. Furthermore, 20MnO(x)/ZSM-5(18) catalyst showed wider temperature window (Delta T = 180 degrees C) with N-2 selectivity over 95% than 20MnO(x)/ZSM-5(360) catalyst (Delta T = 80 degrees C). It can be concluded that the easily reduced and surface enriched MnOx species are favorable for the oxidation of die- thylamine, the moderate and strong surface acid centers are bene ficial to activation of diethylamine and the generation of N-2 .