【摘要】 考察了不同Sn/Pt比的Pt-Sn/Al₂O₃催化剂（络合型）的丙烷脱氢反应性能。并应用原位Mossbauer谱,TPR,O₂吸附等手段对催化剂进行了表征。结果初步表明Pt-Sn/Al₂O₃经过还原后,Sn的还原状态对该催化剂的丙烷脱氢活性及稳定性有极大的影响。在550℃以下还原,Sn以氧化态形式存在,有利于丙烷脱氢反应的活性及选择性,在600℃以上高温还原时,零价锡出现使催化剂活性组分铂的表面中毒而降低活性。当Pt含量一定时,Sn载量愈高,在高温下还原时生成的Sn⁰愈多;低Sn载量的Pt-Sn/Al₂O₃无论高温还原还是低温还原都不易生成Sn⁰。更多还原

【Abstract】 Pt-Sn/Al2O3 cat’alysts with high activity and stability have been commercialized for the dehydrogenation of long-chain paraffin. In order to develop this system for the dehydrogenation of short-chain paraffin, a series of Pt-Sn/Al2O3 catalysts with different Sn/Pt atomic ratios was prepared by impregnating y-Al2O3 with various Pt-Sn-Cl complexes. Their activity and stability for the dehydrogenation of propane were determined in a flow reactor under conditions of pressure 0.5kg/cm2, LHSV 4.0h-1 and hydrogen/propane 3:1(mol). The nature of tin in these catalysts was characterized by Mossbauer spectroscopy, TPR and O2 adsorption.The results show that the valence state of tin in Pt-Sn/Al2O3 catalyst plays an important role in the activity and stability of the catalyst for dehydrogenation of propane. When the catalysts were reduced under temperature below 550℃,SnW reduced to SnII,which enhanced the activity and stability for propene formation.While Sn0, appeared only when the catalysts reduced at about 620℃, poisoned the Pt active site and lowered the conversion of propane, The larger the ratio of Sn/Pt is, the higher the extent of Sn0 formation at high reduction temperature. When Sn/Pt was lower, no Sn0 was found even reduced at high temperature.更多还原