DFRC METHOD FOR LIGNIN ANALYSYS - 1 - NEW METHOD FOR BETA-ARYL ETHER CLEAVAGE - LIGNIN MODEL STUDIES

A new method for selective and efficient cleavage of arylglycerol-beta -aryl (beta-O-4) ether linkages in lignins is described and applied to several Lignin beta-ether models. The term ''DFRC'' was coined for de rivatization followed by reductive cleavage. Derivatization, accompani ed by cell wall solubilization, is accomplished with acetyl bromide (A cBr); reductive cleavage of resulting beta-bromo ethers utilizes zinc in acetic acid. Degradation monomers, 4-acetoxycinnamyl acetates, from beta-ether cleavage by the DFRC method were identified by NMR, CC-MS, and comparison of GC retention times with authentic compounds. Under the conditions used in this study, the beta-ether linkage of all model s was cleaved in very high (> 92%) yield. The DFRC method produces sim pler mixtures of monomers with higher yields than alternative hydrolyt ic methods. Because of its relative simplicity, mild conditions, and e xceptional selectivity, this method should become a powerful analytica l method for lignin characterization.