Comparative study of Caribbean pine (Pinus caribaea L.) wood and bark dioxane lignin

The objective of this paper was to depict some differences between Caribbean pine bark and wood lignin. Gas chromotography (GC) of nitrobenzene oxidation products of extracted wood and bark meals and of corresponding dioxane lignins was performed. The isolated lignins were submitted to IR and UV spectrometry, gel permeation chromatography and differential thermo-gravimetry. The data obtained indicate differences in the contents of condensed bis-guaiacyl structures in the lignins. Contents of phenolic hydroxyl and α-carbonyl groups in both lignins do not markedly differ. There are also certain differences in the thermostability and the molecular weights of compared dioxane lignin preparations.