title: The Influence of Zeolites on Radical Formation During Lignin Pyrolysis.
abstract: Lignin from lignocellulosic biomass is a promising source of energy, fuels, and chemicals. The conversion of the polymeric lignin to fuels and chemicals can be achieved by catalytic and noncatalytic pyrolysis. The influence of nonporous silica and zeolite catalysts, such as silicalite, HZSM5, and HUSY, on the radical and volatile product formation during lignin pyrolysis was studied by in situ high-temperature electron paramagnetic resonance spectroscopy (HTEPR) as well as GC-MS. Higher radical concentrations were observed in the samples containing zeolite compared to the sample containing only lignin, which suggests that there is a stabilizing effect by the inorganic surfaces on the formed radical fragments. This effect was observed for nonporous silica as well as for HUSY, HZSM5, and silicalite zeolite catalysts. However, the effect is far larger for the zeolites owing to their higher specific surface area. The zeolites also showed an effect on the volatile product yield and the product distribution within the volatile phase. Although silicalite showed no effect on the product selectivity, the acidic zeolites such as HZSM5 or HUSY increased the formation of deoxygenated products such as benzene, toluene, xylene (BTX), and naphthalene.
authors.affiliation: Research Dept. Energy and Environment, Paul Scherrer Institut, 5232, Villigen, PSI, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Bährle
authors.affiliation: D-CHAB, Institute for Chemical and Bioengineering, Wolfgang-Pauli-Str. 10, 8093, Zürich, Switzerland.|Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institut, 5232, Villigen, PSI, Switzerland.
authors.forename: Victoria
authors.initials: V
authors.lastname: Custodis
authors.affiliation: D-CHAB, EPR Research Group, Wolfgang-Pauli-Str. 10, 8093, Zürich, Switzerland.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Jeschke
authors.affiliation: D-CHAB, Institute for Chemical and Bioengineering, Wolfgang-Pauli-Str. 10, 8093, Zürich, Switzerland.|Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institut, 5232, Villigen, PSI, Switzerland.
authors.forename: Jeroen A
authors.initials: JA
authors.lastname: van Bokhoven
authors.affiliation: Research Dept. Energy and Environment, Paul Scherrer Institut, 5232, Villigen, PSI, Switzerland. frederic.vogel@fhnw.ch.|Institut für Biomasse und Ressourceneffizienz, Fachhochschule Nordwestschweiz, Klosterzelgstrasse 2, 5210, Windisch, Switzerland. frederic.vogel@fhnw.ch.
authors.forename: Frédéric
authors.identifier: 0000-0001-9762-065X
authors.initials: F
authors.lastname: Vogel
mesh_terms: D002384:Catalysis; D005609:Free Radicals / Q000737:chemistry; D006358:Hot Temperature; D008031:Lignin / Q000737:chemistry*; D017641:Zeolites / Q000737:chemistry*
chemical_list: D005609:Free Radicals; D017641:Zeolites; D008031:Lignin
keywords: EPR spectroscopy; green chemistry; heterogeneous catalysis; pyrolysis; radicals