【摘要】 本文利用正己烷、正庚烷、甲基环戊烷及环己烷等纯烃为原料,在连续微反或脉冲微反装置中进行重整反应,考察钡改性前后Pt/KL分子筛催化剂的反应性能、表面酸性以及抗硫性能的变化。实验结果表明,经钡改性后的Pt/BaKL分子筛催化剂的芳构化活性提高,表面酸性增强,抗硫性能也有所改善。Pt/BaKL分子筛催化剂虽然具有表面酸性,而且也表现出一些双功能的反应特征,但在芳构化反应过程中,单功能的反应机理仍然起着相当重要的作用。更多还原

【Abstract】 The difference between the catalytic property of Pt/alkaline zeolite Pt/KL and its Ba-modified version Pt/BaKL was studied with catalytic reforming of model compounds in pulse and continuous flow type microreactors. At the same conversion level of n-hexane, Pt/BaKL is more selective for hydrocracking reactions than Pt/KL, but its aromatization selectivity is a little bit lower. For methylcyclopentane (MCP) conversion, Pt/BaKL exhibits a better aromatization selectivity and its hydrocracking selectivity is significantly higher than Pt/KL. The dehydrogenation activity of cyclohexane is enhanced by introducting Ba into the catalyst. These results seem to indicate that the incorporation of Ba increased the activity of metal sites and may also have imparted some dual-functional nature to the catalyst. In order to elucidate this point, the acidity of Pt/KL and Pt/BaKL catalysts were determined. By using Raman spectroscopy, the relative intensites of bands due to pyridine chemisorption indicated the Presence of Lewis acidic sites on Pt/BaKL but not on Pt/KL. The resistance to sulfur poisoning was also studied, indicating that the sulfur resistance of Pt/BaKL is better than Pt/KL.These observations can be explained by the joint effect of the enhancement of the metal function and the presence of some dual-functional catalysis in Pt/BaKL. However, even though considerable acidity was found on Pt/BaKL, the results of model compound reforming studies, as the whole, seem to indicate that the predomenating catalytic behaviour of Pt/BaKL remains to be mono-functional as Pt/KL.更多还原