Abstract
The structures and surface acidities of F-Nb/HZSM-5 catalysts with different F/Nb mol ratio were studied using BET, NH3-TPD, FT-IR, MAS-NMR and SEM. The catalytic performance of these catalysts for ethanol dehydration to ethylene was evaluated and correlated with the characterization results. It is found that, dealumination of HZSM-5 occurred after modification and the depth of dealumination increased with the increase of the amount of F added. The extra-framework aluminum species were observed by 27Al MAS NMR with a signal appeared at -13.5. With the increase of F/Nb mol ratio, both weak and strong acid amounts decreased and a new strong acid site was found in the NH3-TPD profile at 500°C. The catalyst with F/Nb mol ratio of 0.7 gave the highest catalytic activity and selectivity. The stability of the catalyst was greatly improved by the addition of F-Nb.
| Original language | English |
|---|---|
| Pages (from-to) | 850-855 |
| Number of pages | 6 |
| Journal | Ranliao Huaxue Xuebao/Journal of Fuel Chemistry and Technology |
| Volume | 39 |
| Issue number | 11 |
| State | Published - Nov 2011 |
Keywords
- Ammonium fluoride
- Dehydration
- Ethanol
- Ethylene
- HZSM-5 molecular sieve
- Niobium oxide
- Solid acid catalyst