镍沉积对HZSM-5沸石裂解性能的影响

THE EFFECT OF DEPOSITION QF Ni ON CATALYTIC CRACKING PERFORMANCE OF ZSM-5

本文以环烷酸镍浸渍模拟镍在ZSM-5中的沉积.以正十六烷裂解考察了浸渍的镍对ZSM-5裂解性能的影响.浸渍的镍对ZSM-5的裂解活性没的影响,而只改变了其选择性.镍的脱氢作用特别明显.利用电子顺磁共振技术(ESR)考察了在裂解中Ni的价态变化.裂解反应使镍的价态从正二价变到正一价,而在空气中再生,ZSM-5中低价态镍可以变回到正二价.水热处理不引起镍的价态变化.

In this investigation the deposition of Ni in ZSM-5 was simulated by impregnating ZSM-5 with Ni naphthenate. Cracking performance of Ni-impregnated ZSM-5 was observed, using the cracking of nhexadecane as the moldel reaction. Impregnating Ni in ZSM-5 has no effect on the cracking activity of HZSM-5, but changes the selectivity of ZSM-5. By using electron-paramagnetic resonance technique the change of valence Ni was traced. Cracking of n-hexadecane causes the valence of Ni to change from+2 to +1 , whereas regeneration of ZSM- 5 in air causes the valence of Ni changing back to +2. Steam treatment has no effect on the change of Ni valence.