Selective Hydrodeoxygenation of Guaiacol Catalyzed by Platinum Supported on Magnesium Oxide
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, with others including methane, n-butane, butenes, n-pentane, and carbon monoxide. The predominant reactions were hydrodeoxygenation (with about 70 % of the guaiacol that was converted forming products that were reduced in oxygen). In contrast, when the catalyst incorporated an acidic support, Pt/γ-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 at guaiacol conversions in the range of about 6–20 %. Pt/MgO underwent deactivation less rapidly than Pt/γ-Al2O3, consistent with a lower rate of coke formation and with observations by scanning transmission electron microscopy showing that the average platinum cluster diameter, approximately 1–2 nm in each catalyst, did not change significantly during operation. The results point to the advantages of basic supports for noble metal hydrodeoxygenation catalysts.
KeywordsHydrodeoxygenation Platinum MgO support Biomass conversion Lignin Biofuels
This research was funded by a fellowship provided by Chevron (T.N.), by the Ernest Gallo Endowed Chair in Viticulture and Enology, and by DOE (Basic Energy Sciences) Grant No. DE-FG02-03ER46057 (C.A.), Grant No. DE-SC0005822 (J.L.), and the University of California Lab Fee Program. We thank Kevin Tay and Leng Mut for help with the experiments. An Agilent Technologies Foundation Research Project Gift provided a GC7890 Refinery Gas Analyzer. We acknowledge beam time and the support of the DOE Division of Materials Sciences for its role in the operation and development of beam line X-18B at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. We thank the beamline staff for valuable support.
- 3.Calvo-Flores FG, Dobado JA (2010) Chem Sus Chem 3:1227Google Scholar
- 9.Zhao HY, Li D, Bui P, Oyama ST (2010) Appl Catal A 391:305Google Scholar
- 10.Bui VN, Laurenti D, Afanasiev P, Geantet C (2010) Appl Catal B 101:239Google Scholar