酸改性天然斜发沸石上丙烷氧化脱氢制丙烯的研究

Oxidative Dehydrogenation of Propane to Propylene over Acid-modified Natural Clinoptilolite

采用不同浓度盐酸对天然斜发沸石进行改性处理,考察了酸改性天然斜发沸石对C3H8氧化脱氢制C3H6反应的催化活性,并对其进行N2物理吸附-脱附、X射线粉末衍射(XRD)、扫描电子显微镜配合X射线能量色散谱(SEM-EDS)、H2程序升温还原(H2-TPR),NH3程序升温脱附(NH3-TPD)等表征.结果表明,小于3.0mol/L的盐酸处理可有效增大天然斜发沸石的比表面积,并改变其酸中心位置、酸量及酸量比例,从而改善其对C3H8氧化脱氢制C3H6反应的催化性能.位于200～250℃的弱酸中心很可能是C3H8氧化脱氢制C3H6反应的活性中心,其酸量及与强酸中心位酸量的比例直接影响催化效果.

In this study,the natural clinoptilolite from Mongolia was modified by using hydrochloric acid leaching.Then,the catalytic activities of some samples were tested using the model reaction of oxidative dehydrogenation of propane（ODP） to propylene.The modified samples were characterized by N2-adsorption desorption,XRD analysis,SEM-EDS,H2-TPR and NH3-TPD.It was found that the weak acid site,acid amount and its ratio with the strong one can be changed effectively by hydrochloric acid（less than 3.0 mol/L）.The weak acid site at 200~250 ℃ is the active center for ODP,possibly.Furthermore,the acid amount and ratio with the strong acid amount affect their catalytic performance directly.