Post 214730 (https://www.thevespiary.org/talk/index.php?topic=11470.msg21473000#msg21473000)
(halfapint: "The Hibbert Ketones of Lignin", Novel Discourse)
Post 190600 (missing)
(halfapint: "Lignin Syringaldehyde Again", Novel Discourse)
Post 190973 (not existing)
Post 165712 (missing)
(drone 342: "Need full article - anyone?", Chemistry Discourse)
Improved Alkaline Oxidation Process for the Production of Aldehydes (Vanillin and Syringaldehyde) from Steam-Explosion Hardwood Lignin
Guoxiong Wu, Michele Heitz, and Esteban Chornet
Ind. Eng. Chern. Res. 33, 718-723 (1994) (https://www.thevespiary.org/rhodium/Rhodium/pdf/syringaldehyde.hardwood.lignin.pdf)
(https://www.thevespiary.org/rhodium/Rhodium/pdf/syringaldehyde.hardwood.lignin.pdf)
Abstract
The production of aldehydes from a steam-explosion hardwood lignin is the main objective of this paper. It is demonstrated that the combined aldehydes yield (vanillin + syringaldehyde + hydroxybenzaldehyde) can reach 14.6 wt% of the lignin isolated from the steam-explosion process. This represents 12.2 wt% of the Klason lignin present in the initial hardwood (Populus tremuloides) and 2.5 wt% of the dry wood. The process steps are relatively simple: aqueous alkaline (13.5 wt% NaOH) oxidation (pure O2) of lignin in the presence of Cu2+ and Fe3+ as catalysts, at 170°C and with 10 min as reaction time. The high yields of aldehydes observed in our work far exceed those obtained in the conventional alkaline air oxidation of spent sulfite liquors. Our results support the concept that biomass-derived oxyaromatic chemicals via improved process strategies may soon challenge existing petroleum-derived routes (vanillin is currently produced via the sequence benzene (https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000318233-file_mxzy.gif) cumene (https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000318233-file_mxzy.gif) phenol (https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000318233-file_mxzy.gif) guaiacol (https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000318233-file_mxzy.gif) vanillin).