n-Alkane isomerization on heteropolyacids. 1. The influence of acid-base properties of alumina systems on the state of supported 12-tungstophosphoric heteropolyacid in Pt-containing catalysts and their activity in n-pentane isomerization

Article abstract of DOI:10.1007/BF02496342

Acid-base properties of bulk 12-tungstophosphoric heteropolyacid (HPWA) and HPWA supported on alumina and fluorinated alumina were studied by DRIFT spectroscopy using adsorption of probe molecules. Catalytic properties of Pt-containing catalysts carried by these supports were studied in n-pentane isomerization. It was shown that the Pt/HPWA/Al2O3 system is almost inactive in isomerization as a result of the interaction of HPWA with basic sites of the alumina support. On the contrary, the presence of acidic sites in fluorinated alumina prevents HPWA destruction and favors the uniform distribution of HPWA on the support surface. As a result, enhancement of the activity and selectivity of the Pt/HPWA/Al2O3-F catalyst in n-pentane isomerization is observed.