Study of mesoporous catalysts for conversion of 2,3-butanediol to butenes

- Conversion of 2,3-butanediol to butenes was studied over mesoporous Cu catalysts.
- Mesopores favor the production of C8= from oligomerization of butenes.
- Micropores favor the production of C3= and C5=-C7= from cracking reaction.
- Selectivity of C8= increases with increasing pore size of the catalysts.
- Hierarchical Cu/meso-ZSM-5 shows higher stability than conventional Cu/ZSM-5.

In this study, three different types of mesoporous materials (Al-MCM-48, Al-SBA-15 and hierarchical ZSM-5 (meso-ZSM-5) where mesoporosity was introduced into ZSM-5 by sodium hydroxide treatment) were loaded with ∼20 wt% CuO and investigated in the conversion of 2,3-butanediol to butenes. The results showed that the introduction of mesopores on the catalysts (Al-MCM-48 and Al-SBA-15 types) could decrease the production of cracking products, especially C3= and C5=-C7= by comparison to the catalyst with ∼20 wt% CuO loaded on HZSM-5; meanwhile, the selectivity of C8= from oligomerization of butenes was found to increase with increasing pore size of the catalysts. In addition, Cu/meso-ZSM-5 catalyst has a performance with similarities to both Cu/ZSM-5 catalyst and mesoporous copper catalysts (Cu/Al-MCM-48 and Cu/Al-SBA-15) since both micropores (diameter of ∼0.55 nm) and mesopores (pore size of ∼23 nm) exist on meso-ZSM-5. Therefore, Cu/meso-ZSM-5 showed high activity for both cracking reactions (C3= and C5=-C7=) and oligomerization (C8=).

57