压力对USY催化甲苯裂解结焦及其前驱体的影响

研究了压力对USY催化剂催化甲苯裂解结焦及其前驱体的影响。采用热重、红外、13C固体核磁、元素分析、色质联用、程序升温氧化法等手段对催化剂上的焦炭和液相产物中的焦炭前驱体进行了考察。结果表明，沉积在催化剂上的焦炭主要为缩合度较高的多环芳烃，随着压力的升高，总的结焦量减少，液相产物中多环芳烃的环数和质量分数呈增加趋势，证明了超临界流体对焦炭前驱体有萃取效果。并探讨了超临界条件下甲苯催化裂解结焦的机理。

Effects of pressure on coke and formation of its precursors during catalytic cracking of toluene over USY catalyst

The effect of pressure on coke and its precursor's formation was studied during catalytic cracking of toluene over USY catalyst.The coke and its precursors were characterized by TGA,FT-IR,solid-state 13C NMR,elemental analysis,GC-MS,and temperature-programmed oxidation(TPO) analysis.The results indicate that coke deposited on the catalyst is mainly composed of polyaromatic hydrocarbons(PAHs).It reveals that the total amount of coke decreases,whereas the number of the rings of PAHs and yields of PAHs in the liquid phase increase with increasing cracking pressure.It is concluded that supercritical fluid plays an important role in extracting coke precursors during catalytic cracking.Finally,the mechanism of coke formation was proposed.