Investigation of structure of milled wood and dioxane lignins of Populus nigra and Cupressus sempervirens using the DFRC method

In this study, derivatisation followed by reductive cleavage (DFRC) were used to investigate milled wood lignin (MWL) and dioxane lignin (DL) structures of Populus nigra and Cupressus sempervirens . After the DFRC reactions, the constituents obtained from these two kinds of lignin were recognised structurally using several chromatographic and spectral methods such as 13 C NMR, GC-MS, and GPC. Comparative results showed that the dominant structural components of the two kinds of lignin are obtained from the cleavage of β -O-4 bonds. The main component of DL and MWL of P. nigra is 4-hydroxy-3,5-dimethoxy-1-phenyl- γ -hydroxypropene (syringyl structures). Also, some guaiacyl structures were observed. The dominant component identified in both lignins of C. sempervirens is 4-hydroxy-3-methoxy-1-phenyl- γ -hydroxypropene (guaiacyl structures). The cleavage method has a good performance for both P. nigra and C. sempervirens and the results obtained are in good agreement with previously published data.