Lignin hydroconversion on MoS2-based supported catalyst: Comprehensive analysis of products and reaction scheme
Résumé
The hydroconversion of a wheat straw soda lignin was studied in a batch
reactor, in tetralin solvent, with a NiMoS/Al2O3 catalyst under H-2
pressure at 350 degrees C. Gaseous, solid and liquid products were
separated, quantified and detailed analyses were performed in order to
describe and to understand the various reactions occurring versus
residence time. In those operating conditions, the weakest beta-O-4 and
alpha-O-4 ether linkages of the lignin were first cleaved. The lignin
was thus progressively converted into smaller hydrogenated and
deoxygenated fragments called lignin residues which were extensively
characterized by GPC and NMR. In the liquid phase, smaller monomers and
dimers were identified by GC x GC/MS and quantified by GC x GC/FID. The
evolution of these molecules was investigated as a function of residence
time in order to investigate the catalytic transformation scheme of
lignin. (C) 2015 Elsevier B.V. All rights reserved.