Pt在APO-5和APO-11分子筛上的分散及催化性能

DISPERSION AND CATALYTIC PROPERTIES OF Pt SUPPORTED ON APO-5 AND APO-11 MOLECULAR SIEVES

Pt 在 APO-11上比在 APO-5上易于分散。环己烷是正己烷在 Pt/APO-5和 Pt/APO-11上芳构化的中间体;Pt/APO-5和 Pt/APO-11显示出单功能芳构化催化剂的某些性质,并适合于正庚烷的芳构化,但大多数 Pt 脱氢中心缺乏终端环化能力。异丙醇分解在 Pt/APO-5和Pt/APO-11上有脱水或脱氢的竞争反应,Pt 的分散有利于丙酮的生成。

H_2 -TPD,TEM and TG -DTA were employed to investigate the effects of de- composition temperature and reduction method on the dispersion of Pt in Pt/APO-5 and Pt/ APO-11.It was found that Pt was dispersed easier on APO-11 than on APO-5 due to the different pore system of the two samples.Both the acidity and pore structure of molecular sieves were important factors affecting the dispersion of Pt and the catalytic property of Pt active centres.Cyclohexane was proved to be the intermediate of n-hexane aromatization on Pt/APO-5 and Pt/APO-11,which exhibited some characteristics of mono-functional aromatization catalysts.Both Pt/APO-5 and Pt/APO-11 were found to be suitable for n- heptane aromatization,but most dehydrogenation active centres of Pt on them lacked termi- nal cyclization ability.Isopropanol could be either dehydrated to form water and propene or dehydrogenated to form hydrogen and acetone on Pt/APO-5 and Pt/APO-11.The disper- sion of Pt favours the formation of acetone.