Study on the physicochemical and isomerization property of Pt/SAPO-11 catalysts promoted by metallic additive
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摘要: 通过浸渍法制备了Pt/SAPO-11催化剂,分步浸渍法制备了LaPt/SAPO-11、CePt/SAPO-11和SnPt/SAPO-11双金属催化剂。通过X射线衍射、低温氮物理吸附、氨程序升温脱附、氢气化学吸附和吡啶吸附红外等手段对所得样品进行了表征。实验结果表明,助剂的引入导致了催化剂的比表面积和微孔孔容降低,B酸量减少而L酸量增加,总酸量有所下降,Pt组分的分散度提高。在360℃时, 对正庚烷的临氢异构化反应中,Pt/SAPO-11催化剂的正庚烷转化率为65.14%,C7异构体收率为61.67%;当分别加入La和Ce,Pt/SAPO-11的正庚烷转化率提高至77.40%和78.12%,C7异构体收率分别提高至69.72%和68.48%;而加入Sn后,Pt/SAPO-11的正庚烷转化率和C7异构体收率分别降至63.22%和59.09%。
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关键词:
- Pt/SAPO-11催化剂 /
- 稀土 /
- 助剂 /
- 正庚烷 /
- 临氢异构化反应
Abstract: Monometallic catalyst Pt/SAPO-11 was prepared by impregnation method. Bimetallic catalysts including LaPt/SAPO-11, CePt/SAPO-11 and SnPt/SAPO-11 were prepared by sequential impregnation method. X-ray diffraction (XRD), nitrogen adsorption, temperatureprogrammed desorption of ammonia (NH3-TPD), chemisorption of hydrogen and Fourier transform infrared spectroscopy (FT-IR) techniques were employed to characterize the catalyst. The results showed that BET surface areas, microporous volume, the amount of Bronsted acid and the total acidity of catalysts decreased slightly with the addition of metal additive La, Ce or Sn. However, the addition could lead to an increase in the amount of Lewis acid. Meanwhile, the introduction of the additive was feasible to promote the dispersity of Pt. In addition, the catalytic performances of catalysts for the hydroisomerization of n-heptane were studied. At 360℃, addition of La and Ce to Pt/SAPO-11 catalyst could increase its conversion of n-heptane from 65.14% to 77.40% and 78.12% respectively, and yield of i-C7 from 61.67% to 69.72% and 68.48%, respectively. While the conversion of n-heptane and yield of i-C7 over SnPt/SAPO-11 catalyst was 63.22% and 59.09% respectively.-
Key words:
- Pt/SAPO-11 /
- rare earths /
- additive /
- n-heptane /
- hydroisomerization
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