title: Aromatic chemicals by iron-catalyzed hydrotreatment of lignin pyrolysis vapor.
abstract: Lignin is a potential renewable material for the production of bio-sourced aromatic chemicals. We present the first hydrotreatment of lignin pyrolysis vapors, before any condensation, using inexpensive and sustainable iron-silica (Fe/SiO2 ) and iron-activated carbon (Fe/AC) catalysts. Lignin pyrolysis was conducted in a tubular reactor and vapors were injected in a fixed bed of catalysts (673 K, 1 bar) with stacks to investigate the profile of coke deposit. More than 170 GC-analyzable compounds were identified by GCxGC (heart cutting)/flame ionization detector mass spectrometry. Lignin oligomers were analyzed by very high resolution mass spectrometry, called the "petroleomic" method. They are trapped by the catalytic fixed bed and, in particular, by the AC. The catalysts showed a good selectivity for the hydrodeoxygenation of real lignin vapors to benzene, toluene, xylenes, phenol, cresols, and alkyl phenols. The spent catalysts were characterized by temperature-programmed oxidation, transmission electron microscopy (TEM), and N2 sorption. Micropores in the Fe/AC catalyst are completely plugged by coke deposits, whereas the mesoporous structure of Fe/SiO2 is unaffected. TEM images reveal two different types of coke deposit: 1) catalytic coke deposited in the vicinity of iron particles and 2) thermal coke (carbonaceous particles ≈1 μm in diameter) formed from the gas-phase growth of lignin oligomers.
authors.affiliation: CNRS, Lorraine University, Reactions and Process Engineering Laboratory, ENSIC, 1, Rue Grandville, 54000 Nancy France.
authors.forename: Roberto Nicolas
authors.initials: RN
authors.lastname: Olcese
authors.forename: George
authors.initials: G
authors.lastname: Lardier
authors.forename: Mohammed
authors.initials: M
authors.lastname: Bettahar
authors.forename: Jaafar
authors.initials: J
authors.lastname: Ghanbaja
authors.forename: Sébastien
authors.initials: S
authors.lastname: Fontana
authors.forename: Vincent
authors.initials: V
authors.lastname: Carré
authors.forename: Frédéric
authors.initials: F
authors.lastname: Aubriet
authors.forename: Dominique
authors.initials: D
authors.lastname: Petitjean
authors.forename: Anthony
authors.initials: A
authors.lastname: Dufour
mesh_terms: D056804:Biofuels; D002384:Catalysis; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008031:Lignin / Q000737:chemistry*; D010578:Petroleum; D016062:Porosity; D014835:Volatilization
chemical_list: D056804:Biofuels; D006841:Hydrocarbons, Aromatic; D010578:Petroleum; D008031:Lignin; D007501:Iron
keywords: bio-oil; biorefinery; catalysis; hydrodeoxygenation; lignin