Chromium oxide zirconia solid acid catalyst for n-pentane isomerization

Abstract

New catalyst based on zirconia (ZrO2) supported by chromium oxide (CrO3) for isomerization of n-pentane was studied. CrO3-ZrO2 was prepared with chromium nitrate by the titration and sol-gel technique. The physical properties of the catalysts were characterized by XRD, BET surface area analyzer, and TEM. The acidity and structure of catalysts were determined by pyridine and lutidine preadsorbed FTIR spectroscopy. The isomerization of n-pentane was carried out at 523 K under hydrogen stream. CrO3-ZrO2 shows the differences in terms of physical properties where the introduction CrO3 partially eliminated the monoclinic phase of ZrO2 and developed new peaks assigned to tetragonal phase of ZrO2. CrO3-ZrO2 also shows a higher specific surface area where it increases in the pore volume of the catalyst compare to its parent zirconia. The IR results indicated that CrO3-ZrO2 catalyst have strong Lewis and weak Brønsted acid sites. The conversion of n-pentane for CrO3-ZrO2 was 32% respectively, while the selectivity to iso-pentane was 100%.