LiNO_3改性ZSM-5分子筛催化乳酸制丙烯酸的失活行为研究  

Deactivation Behavior of ZSM-5 Zeolites Modified by LiNO_3 in Dehydration of Lactic Acid to Acrylic Acid

作　　者：赵庚香 刘华彦[1] 朱秋莲[1] 张泽凯[1] 卢晗锋[1] 陈银飞[1] 

机构地区：[1]浙江工业大学化学工程学院,浙江杭州310014

出　　处：《分子催化》2017年第2期152-158,共7页Journal of Molecular Catalysis(China)

摘　　要：采用X射线粉末衍射(XRD)、傅里叶变换红外光谱(FT-IR)、热重-差示扫描量热分析(TG-DSC)、X射线光电子能谱(XPS)对新鲜和再生Li-ZSM-5催化剂在乳酸脱水制丙烯酸反应中的失活原因进行了研究.结果表明,催化剂失活主要是因为乙醛和丙烯酸在酸性位点结焦生成酮类或醛类积碳前驱体、低聚烃类和高聚烃类积碳,导致活性位减少而失活.催化剂经焙烧再生,若碳物种不能脱除干净,将导致积碳速率增加,活性位减少的速度加快,稳定性降低.The deactivation behavior of fresh and regenerated Li-ZSM-5 catalyst in the dehydration of lactic acid to acrylic acid was studied by X-ray Powder Diffraction （XRD）, Fourier transform infrared spectroscopy （FT-IR） and thermogavimetry- differential scanning calorimetry（TG-DSC） and X-ray photoelectron spectroscopy （XPS）. It was found that the catalyst deactivation was mainly due to the formation of ketones or aldehydes coke precursors from ac- etaldehyde and acrylic acid at the acid sites, furthermore carbon deposits of low hydrocarbons and high hydrocar- bons resulted in decrease of active sites. Incomplete removal of the carbon species deposited in the catalyst surface during the regeneration by calcining will lead to an increase in carbon deposition rate during the next cycle, and ac- celerating the rate of active sites reduction, so the stability of Li-ZSM-5 decrease.

关 键 词：失活 乳酸脱水 Li-ZSM-5分子筛 积碳 稳定性 

分 类 号：O643.32[理学—物理化学]