Evaluation of the acidic properties of the B2O3–Al2O3 and Pt/B2O3–Al2O3 systems by spin probe EPR spectroscopy and their correlation with the occurrence of the joint hydroisomerization of heptane and benzene

Abstract

The acidity of a series of borate-containing aluminum oxide samples with the concentrations of B₂O₃ from 0.9 to 27.5 wt % and Pt-containing catalysts obtained on their basis was studied by spin probe EPR spectroscopy. With the use of anthracene and the TEMPO nitroxide radical as probe molecules, it was established that an increase in the B₂O₃ content of the B₂O₃–Al₂O₃ and Pt/B₂O₃–Al₂O₃ systems leads to a symbatic increase in the number of medium-strength Brønsted acid sites (BASs). In this case, the yields of target hydroisomerization products (isoheptanes and methylcyclopentane) correlate with the number of BASs.