Cellulose esters of hydroxycinnamic acids, namely ferulic-, p-coumaric-, and caffeic acid, are synthesized by Mitsunobu esterification applying triphenylphosphine and diisopropyl azodicarboxylate in N,N-dimethylacetamide/LiCl. The reaction is found to be highly selective and took place at primary hydroxyl groups at position 6 of cellulose without undesired conversion of double bonds and phenolic hydroxyl groups. Molecular structure characterization is performed by FTIR- and NMR spectroscopy. The products are soluble in dimethyl sulfoxide and possessed degree of substitution (DS) values of up to 0.5. DS values are determined by two independent methods, namely H-1 NMR spectroscopy of peracetylated derivatives and UV spectroscopy of extracted ferulic acid. The synthesis of cellulose hydroxycinnamates is very important to design lignocellulosic model systems and antioxidative bioinspired materials.
|Number of pages
|Macromolecular chemistry and physics : MCP
|Published - Nov 2021
- cellulose, ferulic acid, hydroxycinnamate, Mitsunobu reaction, selective esterification, ANTIOXIDANT ACTIVITY EVALUATION, FERULIC ACID