| Popis: |
Comparative study of Pt-loaded tungstated zirconia and sulfated zirconia catalysts in the isomerization of n-heptane and n-hexane was carried out. According to the FTIR-spectroscopy of adsorbed pyridine, it was found that the Pt/SZ catalyst is characterized by the presence on the surface of stronger Lewis acid sites (a.b. 1448 cm−1) and Bronsted acid sites (a.b. 1543 cm−1) in comparison with the Pt/WZ catalyst (a.b. 1445 and 1538 cm-1, respectively). Moreover, the catalysts are characterized by a different distribution of acid sites: for Pt/SZ, the amount of LAS is five times higher than the number of BAS; for the Pt/WZ catalyst, on the contrary, the number of Bronsted sites exceeds the fraction of LAS by about two times. The difference between the tungstated and sulfated zirconia systems in terms of strength and the number of acid sites explains various regularities of C6-C7 alkane isomerization. |
