Oxidative degradation of monomeric and dimeric phenylpropanoids: reactivity and mechanistic investigation

Analysis of printing and writing papers by using direct analysis in real time mass spectrometry

“…However, upon close inspection, there are more differences than similarities between the DART-MS spectra and those obtained by using Py-MS. The two lowest mass resonance stabilized monomeric benzofuran products in the DART-MS spectra (m/z 131 and m/z 161) have no apparent analogs in Py-MS spectra: Benzofurans can be formed from oxidation of phenylcoumaran lignin structures [52]. Peaks that represent molecular ions of coniferyl and sinapyl alcohols (m/z 180 and m/z 210, respectively) are seen in Py-MS spectra, but DART-MS spectra instead reveal peaks from the resonance stabilized allylic carbenium ions (m/z 163 and m/z 193, respectively) that arise by loss of water from the (M + H) + ions of the two alcohols [50].…”

Catalytic Conversion of Lignocellulosic Biomass to Value-Added Organic Acids in Aqueous Media

“…Based on the different structure of the lignin precursors, the oxidation reaction pathways can be divided into three categories. First, p-coumaryl alcohol resembling lignin model compounds to 4-hydrobenzaldehyde [18,26,41,43] and then 4-hydrobenzoic acid [106]; Second, coniferyl alcohol resembling lignin model compounds to vanillin [9,81] and vanillic acid [36]; Third, sinapyl alcohol resembling lignin model compounds to syringaldehyde and syringic acid.…”

Electrochemical and IR spectroscopic detection of oxidation products of the monomer and dimer of vanillyl alcohol in a sol–gel processed silicate matrix

“…5) product 4 is indeed formed in the silicate film. As reported in the literature the aliphatic hydroxyl group may also undergo further oxidation to a conjugated carbonyl group [40]. Our results suggest that a 1,4-quinone derivative (compound 5) is the next product of the Van oxidation reaction.…”

“…On the other hand, phenols may be also the products of the oxidation reaction. The formation of the carboxylic group indicates breaking of the ether bond of the dimer molecule, which indeed was detected in the oxidation of various lignin model compounds in the presence of different catalysts [40][41][42][43][44]. Two [40,42,44].…”