Fig. HSQC Spectrum of Aromatic Region for oven dried lignin reference sample 4-1
Fig. HSQC Spectrum of Aliphatic Region for oven dried lignin reference sample 4-1
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Aromatic Region:
Significant reduction in signal intensity, particularly for G5 and G6 peaks, is evident. This indicates partial degradation or condensation reactions affecting guaiacyl and syringyl units at higher drying temperatures. The pronounced condensation results in a loss of structural resolution.
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Aliphatic Region:
A sharp decline in methoxy (OMe) and side-chain linkages is observed, reflecting extensive cleavage of aliphatic ether bonds. The degradation is consistent with the harsher drying conditions.