原位生成Fe基催化剂催化木质素快速热解生成单环芳香烃的研究

Fast catalytic pyrolysis of lignin into monocyclic aromatic hydrocarbons over in-situ generated Fe-based catalyst

探讨了铁矿石原位生成的Fe基催化剂对硫酸盐木质素催化热解的情况。研究使用透射电子显微镜对反应前后的催化剂进行表征,以探究催化剂形态变化;通过分段热解反应器联合飞行时间质谱评估催化剂的性能。结果表明,反应前催化剂呈颗粒状,而反应后催化剂几乎烧结。与未还原铁矿石和商业Fe_(2)O_(3)相比,还原铁矿石显著促进了单环芳香烃的产生。在最优反应温度550℃下,单环芳香烃的相对含量高达到81%,其中苯、甲苯、二甲苯和三甲基苯的相对含量分别为46%、34%、13%和7%。基于脱羟基和脱甲氧基的反应原理,提出了硫酸盐木质素催化热解的可能途径。使用的低成本铁矿石催化剂有望应用于硫酸盐木质素热解,以生产有价值的生物基芳香烃。

This study examined the catalytic pyrolysis of kraft lignin using an in-situ generated Fe-based catalyst from iron ore.The fresh and spent catalysts were characterized by a transmission electron microscope to investigate the morphological changes of the catalysts.To evaluate the catalysts′performance,a segmented pyrolysis reactor coupled with time-of-flight mass spectrometry was employed.The results showed that the fresh catalysts had a particle-like morphology,while the spent catalysts appeared sintered.Compared to unreduced iron ore and commercial Fe_(2)O_(3),reduced iron ore significantly promoted the production of monocyclic aromatic hydrocarbons.A yield of monocyclic aromatic hydrocarbons reached 81%at the optimized reaction temperature of 550℃,with benzene,toluene,xylene and trimethylbenzene accounting for 46%,34%,13%and 7%respectively.Moreover,the possible pathway for kraft lignin via catalytic pyrolysis was proposed based on dehydroxylation and demethoxylation.This work suggests that a low-cost iron ore catalyst could potentially be applied to pyrolyze kraft lignin to produce valuable bio-based aromatic hydrocarbons.