长链烷烃(n-C_(10～12))脱氢制单烯烃催化剂的研究Ⅱ.Pt-Sn/MgAl_2O_4催化剂上C_(12)脱氢反应行为

Investigation on the catalysts for dehydrogenation of long chain paraffins (n-C_(10-13)) to mono-olefins Ⅱ. Dodecane dehydrogenation behaviors over Pt-Sn/MgAl_2O_4 catalysts

采用真空浸渍法制备Pt-Sn/MgAl_2O_4和Pt-Sn/γ-Al_2O_3催化剂。对两种催化剂进行C_(12)脱氢催化性能评价比较,并使用BET、XRD、CO吸附、TPR、NH_3-TPD和TG等手段对催化剂进行表征。NH_3-TPD测定结果表明,Pt-Sn/MgAl_2O_4催化剂比Pt-Sn/γ-Al_2O_3催化剂具有较弱的酸性。Pt-Sn/MgAl_2O_4催化剂的初始转化率(21.6%)比Pt-Sn/γ-Al_2O_3催化剂初始转化率(22.6%)低,但其单烯烃选择性(83.9%)比后者(73.6%)高。

Pt-Sn/MgAl2O4 and Pt-Sn/γ/-Al2O3 catalysts were prepared by vacuum impregnation method and used for dodeeane dehydrogenation. The catalysts were characterized by BET, XRD, CO chemisorp- tion, TPR, NH3-TPD and TG. NH3-TPD results showed that acidity of Pt-Sn/MgAl2O4 was weaker than that of Pt-Sn/γ-Al2O3. Pt-Sn/MgAl2O4 exhibited lower initial conversion （21.6% ） than Pt-Sn/γ-Al2O3 catalyst （22.6%）, but higher selectivity to mono-olefins （83.9%） than Pt-Sn/γ-Al2O3 （73.6%）.