Biomimetic vanadate and molybdate systems for oxidative upgrading of iono- and organosolv hard-and softwood lignins
DATA:
2020-09-16
IDENTIFICADOR UNIVERSAL: http://hdl.handle.net/11093/1546
VERSIÓN EDITADA: https://www.mdpi.com/2227-9717/8/9/1161
MATERIA UNESCO: 3303.03 Procesos Químicos ; 3303.01 Tecnología de la Catálisis ; 3312.13 Tecnología de la Madera
TIPO DE DOCUMENTO: article
RESUMO
Recently reported acetosolv soft- and hardwood lignins as well as ionosolv soft- and hardwood lignins were transformed into monomeric aromatic compounds using either a vanadate or a molybdate-based catalyst system. Monomers were generated with remarkable, catalyst-dependent selectivity and high depolymerisation yields via oxidative exo- and endo-depolymerisation processes. Using the vanadate–hydrogen peroxide system on acetosolv pine lignin, vanillin and isovanillin were produced as main products with depolymerisation yields of 31%. Using the molybdate system on acetosolv and ionosolv lignin, vanillic acid was the practically exclusive product, with depolymerisation yields of up to 72%. Similar selectivities, albeit with lower depolymerisation yields of around 50% under standardised conditions, were obtained for eucalyptus acetosolv lignin, producing vanillin and syringaldehyde or vanillic acid as products, by using the vanadate- or the molybdate-based systems respectively.