Stereo-Preference in the degradation of the erythro and threo isomers of β-O-4-type lignin model compounds in oxidation processes. part 2: In the reaction with hydroxyl and oxyl anion radicals under hydrogen peroxide bleaching conditions

Predominant formation of aromatic aldehyde and acid from a dimeric β-O-4-type lignin model compound under hydrogen peroxide bleaching conditions with high pH levels

“…The synthesis of compound 1 and separation of the E and T isomers were described in our previous studies [29,30]. The 1 H-and 13 C-NMR spectral data of compound 1 were reported in our previous study [29].…”

“…All chemicals except compound 1 were commercially available and used without further purification [29,30]. The synthesis of compound 1 and separation of the E and T isomers were described in our previous studies [29,30].…”

“…The total amount of hydrogen peroxide added was about 1.8 mmol. The detailed procedures were reported in our previous study [30]. This system is described as the H 2 O 2 system in the following text.…”

“…The addition of 20 μL of a 30% hydrogen peroxide solution was repeated ten times at intervals of 10 min [30]. The total amount of hydrogen peroxide added was about 1.8 mmol.…”

“…1), was individually treated with alkaline oxygen or hydrogen peroxide to examine the E or T stereo-preference of active oxygen species (AOS) generated in the system under conditions simulating a practical pulp bleaching process [29,30]. This study reports that 3,4-dimethoxybenzaldehyde (veratraldehyde, Fig.…”