(715c) Tunable Mixed Metal Oxides for Selective Hydrogenation and Ring-Opening of Furfuryl Alcohol

Lignocellulosic biomass can be broken down to furfural and furfuryl alcohol, major platform chemicals, which can be further catalytically converted into fuel additives (2-methylfuran, 2-MF) and polymer precursors (1,5-pentanediol, 1,5-PD) under hydrogen atmosphere. A shift towards catalysts based on multi-metal systems has shown promise in developing more selective catalysts for biomass conversion. Prior work for vapor phase hydrogenolysis to 2-methylfuran conducted over Ni-Fe/SiO₂[1], Mo₂C[2], and Co-Al[3] demonstrated yields of 80% (250 °C), 55% (180 °C), and 42% (155 °C), respectively. In liquid phase batch systems other bifunctional catalysts such as Ir-ReO_x[4] and Pt/Co-Al[5] are active for ring-opening of furanics. However, there is still a desire to increase yields to these value-added products, reduce the need for expensive precious metals, and further our understanding of the electronic environment of bifunctional catalysts.

The work presented demonstrates the versatility of mixed metal oxides (MMO) derived from layered double hydroxides (LDH) to conduct furanic chemistry after undergoing a reduction pretreatment. By either doping small amounts of Fe or Cu into a Co-Al oxide matrix improvements towards selectivity and activity are observed for side chain hydrogenolysis and ring-opening, respectively. The resulting multi-metal catalysts can achieve yields of 82% towards 2-MF (Co-Fe-Al) [6] and 42% towards 1,5-PD (Cu-Co-Al) under optimizing conditions, which is comparable or better than prior catalysts with similar mechanisms. To better understand the electronic environment, various spectroscopic experiments were used to develop a model of how each oxide species was changed under reducing conditions.

This work provides a comprehensive account of the versatility of non-precious metal MMO catalysts for biomass conversion. By tuning the metal addition, various chemistries can be targeted in furanic conversion.

References

1. Sitthisa, S., An, W., and Resasco, D.E., J. Catal.284, 90 (2011).

2. Lee, W.-S., Wang, Z., Zheng, W., Vlachos, D. G., and Bhan, A., Catal. Sci. Technol. 4, 2340 (2014).

3. Sulmonetti, T. P., Pang, S. H., Claure, M. T., Lee, S., Cullen, D.A., Agrawal, P. K., and Jones, C. W., Appl. Catal., A 517, 187 (2016).

4. Koso, S., Furikado, I., Shimao, A., Miyazawa, T., Kunimori, K., and Tomishige, K. Chem. Commun. 2035 (2009).

5. Xu, W., Wang, H., Liu, X., Ren, J., Wang, Y., and Lu, G. Chem. Commun.47, 3924 (2011).

6. Sulmonetti, T. P., Hu, B., Ifkovits Z., Lee, S., Agrawal, P. K., and Jones, C. W., ChemCatChem (2017) Accepted.