Properties versus application requirements of solubilized lignins from an elm clone during different pre-treatments.
Kraft pulping, organosolv process and acid hydrolysis were applied on an elm clone. The solubilized lignins were recovered and analyzed. Kraft pulping and acid hydrolysis led to lignins with higher phenolic OH content as result of extensive cleavage of β-O-4' linkages, as revealed by 13C solid state and 13C-1H heteronuclear single quantum coherence nuclear magnetic resonance. This depolymerization also yielded lower molecular weight lignins inferred by size exclusion chromatography. Contrarily, organosolv process gave rise to a lignin with a more preserved structure, maintaining a large number of β-O-4' linkages. Consequently, organosolv lignin presented lower phenolic OH content and higher molecular weight. Moreover, the high content of the labile native β-O-4' linkages in organosolv lignin resulted in a lower thermostability as compared to the kraft and acid lignins. On the other hand, the solubilized lignins from kraft and acid processes displayed an enrichment of S-units, whereas lignin from organosolv process was slightly enriched in G-units, containing all of them different native as well as pre-treatment derived units. These results could help to increase the inventory of lignin sources available for future lignin-based products, for which knowledge of the lignin properties versus application requirements is crucial.
['Eugenio|María E|ME|', 'Martín-Sampedro|Raquel|R|', 'Santos|José I|JI|', 'Wicklein|Bernd|B|', 'Martín|Juan A|JA|', 'Ibarra|David|D|']
D066241:Carbon-13 Magnetic Resonance Spectroscopy D002999:Clone Cells D008031:Lignin D008968:Molecular Conformation D008970:Molecular Weight D012995:Solubility D017550:Spectroscopy, Fourier Transform Infrared D013696:Temperature D013818:Thermogravimetry D034403:Ulmus
Solubilized lignins Chemical and structural features Ulmus minor clone