β沸石作为一种重要的酸催化剂,结构和酸性对其催化性质有重要影响。通过两种不同的联合处理方式(酸-焙烧处理、酸-水热处理)对其结构和性质进行了调变,并对改性所得的β沸石进行了低温氮气物理吸附、X射线电子能谱(XPS)和红外(IR)的表征分析,最后以正辛烷为原料在500℃下进行了催化裂化反应性能评价。研究发现,可通过不同的处理方法调变最终改性沸石的比表面积和两种Lewis酸性(L1445和L1455)。经焙烧和酸处理后所得样品较经水热和酸联合处理所得样品具有更好的正辛烷裂化活性。前者较高的BET比表面积和Lewis酸是其催化裂化活性好的原因。通过这两种不同的改性方式,β沸石的B酸和两种L酸酸量及其织构性质得到调变,从而使最终沸石的催化性能产生差异。
β-Zeolite, an important acidic catalyst, its structure and acidity can significantly influence the catalytic activity. Through two combinational treatments of acid-calcination and acid-steaming, the structure and acidity of β-zeolite were tuned. After treatment, the modified β-zeolites was characterized by N2 adsorption and desorption, X-ray photoelectron spectroscopy(XPS), and infrared spectra(IR). The activity for catalytic cracking of n-octane at 500℃ was evaluated. It showed that BET specific area and Lewis acid sites(L1445 and L1455) were tuned by different treatments. The catalyst by acid-calcination treatment exhibited better activity for catalytic cracking of n-octane than acid-steaming treatment. The higher BET surface area and the Lewis acid sites account for the higher catalytic cracking activity of the catalyst by acid-calcination treatment. The concentrations of Br?nsted acid and two types of Lewis acid as well as textural properties were tuned, which lead to the difference in catalytic activity between the original and final β-zeolites.