Study Of Catalytic Synthesis Of2-methylpyrazine Over Cu-La-Al-O Oxide And Others

Pyrazine and its derivatives are valuable industrial chemicals.2-methylpyrazine (2-MP), the lower alkyl-substituted pyrazine, is widely used in the synthesis of perfumery, pharmaceutical and agricultural chemical industries. Since the wide applications, the synthetic study of2-MP get more attentions.In this paper,2-MP was synthesized by catalytic reaction of ethylene diamine and propylene glycol. On the basis of previous exploration, the catalytic properties of the Cu-La-A1-O oxide catalysts and the modified13X zeolite catalysts were studied.Firstly, the CuO/LaO3/γ-Al2O3oxides were prepared by an improved amorphous citric precursor (IACP) method and characterized by X-ray diffraction, temperature programmed desorption of ammonia, and temperature programmed reduction techniques. The influences of metal mole ratios, calcination temperature, reaction temperature, gas hourly space velocity (GHSV) on the catalytic activity were investigated. The results demonstrated that the performance of the CuO/La2O3/γ-Al2O3catalyst with n (Cu):n (Al)=4:6at the calcinations temperature of700℃was the best. As the reaction temperature at 320℃, using a feed of ED, PG, and water as1:1:2molar ratio and the space velocity as1815h-1, the yelid of2-MP reached to82.7%, while the conversion of PG was about100%. In addition, the catalyst life and regeneration were studied. The catalyst began to inactivative when it was used10hour continuely, and its catalytic properties could be recovered to its original state by burning charcoal and reducting.Secondly, in order to investigate the influence of catalyst preparation on their performance, CuO/La2O3/γ-Al2O3catalysts were prepared by a2-step IACP method, and their catalytic properties were tested. The results showed that the property of10%CuO/37%La2O3-γ-Al2O3had the best performance and the yield of2-MP reached84.0%.Lastly, to understand the modified13X zeolite catalysts well, we choosed copper, silver species as loading metal to study the catalytic properties of the dual-component metal modified13X zeolite catalysts. The best catalytic performance was obtained for7%Cu//10%Ag/13X zeolite catalyst, and the yield of2-MP was73.4%.In conclusion, the performance of the Cu-La-Al-O catalyst was observed to be better than that of others.