Propane transformation over H-ZSM5 zeolite modified with germanium
Propane transformation over H-ZSM5 zeolite modified with germanium
复制标题
锗改性 H-ZSM5 沸石上的丙烷转化
DOI：
10.1023/a:1019032316270
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发表时间：
1997
影响因子：
2.8
通讯作者：
M. Schmal
中科院分区：
文献类型：
--
作者：
C. Salguero;Y. L. Lam;M. Schmal
研究了Ge、Pt和Pt-Ge改性H-ZSM5沸石的丙烷芳构化反应。芳构化在微反应器中在773K和大气压下进行。在 H-ZSM5 上添加锗提高了丙烷转化活性，但降低了对芳香族化合物的选择性。丙烷在Pt/H-ZSM5上的转化表明活性显着增加，而对芳烃的选择性降低，而在双金属Pt-Ge/H-ZSM5催化剂上，活性和对芳烃的选择性均增加。在 773 K 下通过 GeO2/SiO2 进行丙烷脱氢，在 673 K 下通过 H-ZSM5 和 Ge/H-ZSM5 进行正庚烷转化。结果证实了 GeO2 的脱氢能力，并且在 H-ZSM5 和 Ge/H-ZSM5 上显示出相似的正庚烷转化活性和选择性。通过TPD/NH3 和IR/Py 分析测定了催化剂的酸性。结果表明，总酸度和强酸度均随着锗的添加而降低。因此，锗似乎由于GeO2的脱氢能力而影响丙烷转化的活性，而由于环化能力较低，通过降低酸度和强酸位点的数量，芳烃的选择性降低。相比之下，Pt-Ge/H-ZSM5催化剂对芳烃具有最高的选择性（53.4%），这是由于铂氢解能力的降低。 Pt-Ge/H-ZSM5催化剂的TPR结果表明Pt-Ge之间存在相互作用，从氢消耗中可以看出Ge4+部分还原为Ge2+，这归因于金属铂的存在。
The propane aromatization was studied over H-ZSM5 zeolite modified by Ge, Pt and Pt-Ge. The aromatization was performed in a micro-reactor at 773K and at atmospheric pressure. The addition of germanium on H-ZSM5 increases the activity for propane transformation but decreases the selectivity toward aromatic compounds. The transformation of propane on Pt/H-ZSM5 indicates a significant increase in the activity and a decrease in the selectivity toward aromatics, while on the bimetallic Pt-Ge/H-ZSM5 catalyst both the activity and the selectivity toward aromatics increase. The dehydrogenation of propane over GeO2/SiO2 at 773 K and the n-heptane transformation overH-ZSM5 and Ge/H-ZSM5 at 673 K were performed. Results confirm the dehydrogenation capacity of GeO2 and show similar activity and selectivity for n-heptane conversion on H-ZSM5 and Ge/H-ZSM5. The acidic properties of the catalysts were determined by TPD/NH3 and IR/Pyanalyses. Results show that both the total and strong acidity decrease with the addition of germanium. Therefore, it seems that germanium affects the activity of propane conversion due to the dehydrogenation capacity of GeO2,while the selectivity toward aromatics decreases due to the lower capacity of cyclization, by decreasing the acidity and the number of strong acid sites. In contrast, the Pt-Ge/H-ZSM5 catalyst presents the highest selectivity toward aromatics (53.4%) which is attributed to the decrease in hydrogenolysis capacity of platinum. The TPR results of the Pt-Ge/H-ZSM5 catalyst indicate interaction of Pt-Ge, and from the hydrogen consumption it was seen that Ge4+ is partially reduced to Ge2+, which is attributed to the presence of metallic platinum.