(476e) Selective Hydrodeoxygenation of Guaiacol Catalyzed by Pt/MgO

T. Nimmanwudipong, C. Aydin, J. Lu, R. C. Runnebaum, K. Brodwater, N. D. Browning, D. E. Block, and B. C. Gates

The conversion of guaiacol catalyzed by Pt/MgO in the presence of H₂ was investigated with a flow reactor at 573 K and 140 kPa.  Among the dozens of reaction products identified by gas chromatography (GC) and GC/mass spectrometry, the predominant ones were phenol, catechol, and (surprisingly) cyclopentanone, and others included methane, n-butane, n-pentane, butenes,  and carbon monoxide. The predominant reactions were hydrodeoxygenation (with about 70% of the total products being reduced in oxygen), but when the catalyst incorporated an acidic support, Pt/g-Al₂O₃, other reactions became kinetically significant, exemplified by transalkylation, and the selectivity to deoxygenated products was reduced to about half the value observed with Pt/MgO. Pt/MgO underwent deactivation slightly more slowly than Pt/g-Al₂O₃, consistent with the lower rate of coke formation and with the observations by transmission electron microscopy showing the lack of sintering of the platinum (the average platinum particle size (which was approximately 1–2 nm in each catalyst) did not change significantly during operation.