915962-66-2Relevant academic research and scientific papers
Degradation of β-O-4 model lignin species by vanadium Schiff-base catalysts: Influence of catalyst structure and reaction conditions on activity and selectivity
Parker, Heather J.,Chuck, Christopher J.,Woodman, Timothy,Jones, Matthew D.
, p. 40 - 47 (2016)
In the pursuit of value-added products from the degradation of the abundant aromatic biopolymer lignin, homogeneous catalysis has the potential to provide a mild, selective route to monomeric phenols. Homogeneous vanadium catalysts have previously been shown to effectively cleave dimeric β-O-4 model lignin compounds, with selectivity for C-C or C-O cleavage, or benzylic oxidation, depending on the ligand structure and oxidation state of the metal. In this study, a systematic kinetic investigation was undertaken in order to gain further understanding of the role of ligand structure and reaction conditions on the activity of vanadium Schiff-base catalysts towards a non-phenolic β-O-4 model lignin dimer, and the selectivity of these species towards C-O bond cleavage. Catalytic activity was found to be increased by the addition of bulky, alkyl substituents at the 3′-position of the phenolate ring, whereas electron-withdrawing substituents were found to dramatically reduce activity irrespective of their size. Selective depolymerization of a phenolic β-O-4 dimer was also achieved.
Non-oxidative vanadium-catalyzed co bond cleavage: Application to degradation of lignin model compounds
Son, Sunghee,Toste, F. Dean
supporting information; experimental part, p. 3791 - 3794 (2010/08/22)
(Chemical Equation Presented) New direction: Changes In the ligand structure divert the reactivity of vanadium (V) oxo complexes from alcohol oxidation to a novel non-oxidative C-O bond cleavage. Thus, highly functionalized aryl enones can be selectively generated from lignin model compounds by vanadium-catalyzed cleavage of the β-O-4 linkage (see scheme; N blue, O red).
