New Azo Derivatives of Ethanol Lignin: Synthesis, Structure, and Photosensitive Properties

• Published in: Materials Vol. 16; no. 4; p. 1525
• Main Authors: Borovkova, Valentina S, Malyar, Yuriy N, Vasilieva, Natalia Yu, Skripnikov, Andrey M, Ionin, Vladislav A, Sychev, Valentin V, Golubkov, Viktor A, Taran, Oxana P
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 11-02-2023; MDPI
• Subjects: Acetaldehyde; Alcohol; Alcohol, Denatured; Aqueous solutions; Azo compounds; azo lignins; Biomass; Chromatography; cis–trans isomerism; Coupling; Diazo compounds; diazonium compounds; Ethanol; Fourier transforms; Infrared spectroscopy; Laboratories; Lignin; Lignocellulose; Liquid chromatography; Macromolecules; Molecular weight; Nitrogen; NMR; Nuclear magnetic resonance; Photosensitivity; Polyethylene glycol; Polymers; Potassium; Software; Substitution reactions; Germany; Russia; United States > US; lignin; photosensitivity; cis–trans isomerism; azo lignins; diazonium compounds
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma16041525

Water-soluble azo derivatives of lignin were synthesized by the azo coupling reaction using organosolv ethanol lignin and diazonium salts based on sulfanilic acid and p-nitroaniline. The structure of azo derivatives of lignin were studied by nuclear magnetic resonance, Fourier-transform infrared spectroscopy, and gel permeation chromatography. It was found that the azobenzene bonds formed in the azo coupling reaction of macromolecules impart the photosensitive properties to the synthesized polymers via cis-trans photoisomerization of the diazobenzene group. It was shown experimentally that the synthesized polymers exhibited good solubility both in the aqueous media in a wide (2-12) pH range and in DMSO and THF organic solvents, which opens up new prospects for their application.