CHEMICAL AND SPECTRAL CHARACTERISTICS OF ANNUAL PLANT LIGNINS MODIFIED BY HYDROXYMETHYLATION REACTION

摘要

This paper aims at the synthesis and chemical and spectral characterization of lignins from annual plants (LI - lignin from wheat straw, and L2 - lignin from grass), modified by hydroxymethylation with formaldehyde in alkaline environment. The derivatives synthesized by this reaction were characterized by the introduced functional groups, which has been related to the consumption of formaldehyde under different conditions. Subsequently, additional information on the changes has been obtained by spectral studies (FTIR, 'H NMR) and high performance steric exclusion chromatography (HPSEC). Studies have revealed some functional changes, related to both different reactivity of lignins and reaction conditions.