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Higher alcohol production from ethanol over occluded [Mg4(OH)4]4+ clusters in MgO/KNaX
Author(s)
Date Issued
February 25, 2022
Type
Article
Abstract
Conversion of ethanol to higher alcohols was studied over MgO/KNaX, prepared by ion exchange with Mg(OAc)2, followed by KOH washing. The catalysts were characterized by XRF, XRD, SEM, BET, 27Al MAS NMR, EXAFS, NH3- and CO2-TPD. All catalysts showing MgO nanopetals and aggregates on the external surface, contained occluded [Mg4(OH)4]4+ clusters in the zeolite cavities, providing medium basic (Mb) and acid (Ma) sites. Ethanol conversion and higher alcohols selectivity (up to 78%) increased with Mb/Ma ratio due to the increase in both MgO (4–6 wt%) and K (14.7–17.3 wt%) loadings. Decreasing occluded [Mg4(OH)4]4+ clusters and/or increasing MgO aggregates led to the lower conversion and yields of higher alcohols. The essential role of the occluded [Mg4(OH)4]4+ clusters in producing higher alcohols was verified by the reactions using various control catalysts. The MgO/KNaX showed high stability even after steaming at 380 °C, as well as being regenerated by calcination (450 °C in air).
Citation
Applied Catalysis A General, 632, 2022